thiopental and Arrhythmias--Cardiac

Topics: Anesthesia, Conduction; Anesthetics, Local; Animals; Apnea; Arrhythmias, Cardiac; Barbiturates; Central Nervous System; Critical Care; Diazepam; Drug Hypersensitivity; Epinephrine; Female; Humans; Infusions, Parenteral; Intubation, Intratracheal; Male; Monitoring, Physiologic; Oxygen Inhalation Therapy; Pregnancy; Procaine; Seizures; Succinylcholine; Thiopental

Topics: Anesthetics; Arrhythmias, Cardiac; Catecholamines; Digitalis Glycosides; Electroshock; Heart Diseases; Humans; Hypercapnia; Hypertension; Hypothermia, Induced; Hypoxia; Intubation; Neostigmine; Potassium; Scopolamine; Succinylcholine; Surgical Procedures, Operative; Thiopental

Thiopental prolongs the QT interval more than propofol, and the two induction agents were compared in patients with subarachnoid haemorrhage predisposed to electrocardiographic abnormalities and cardiac dysrhythmias.. Twenty-nine patients were studied randomly. Anaesthesia was induced with either thiopental or propofol and fentanyl; vecuronium was used as a neuromuscular blocking agent. The electrocardiogram and arterial blood pressure were monitored from before the induction of anaesthesia to 2 min after endotracheal intubation.. The median QT interval was at baseline 423 ms in the thiopental group and at 432 ms in the propofol group, and it increased in the thiopental group to 446 ms and decreased in the propofol group to 425 ms (P < 0.01 between groups). After induction and endotracheal intubation, the number of patients with increased QT dispersion was greater in the propofol group (P < 0.05). The incidence of cardiac dysrhythmias was similar in the study groups.. Thiopental and propofol are equally suitable for the induction of anaesthesia in patients with subarachnoid haemorrhage.

Topics: Anesthesia, Intravenous; Anesthetics, Intravenous; Arrhythmias, Cardiac; Electrocardiography; Female; Heart Rate; Humans; Male; Middle Aged; Monitoring, Intraoperative; Propofol; Subarachnoid Hemorrhage; Thiopental; Time Factors

The aim of this study was to compare the effect of three different induction techniques, with or without neuromuscular block, on tracheal intubation, haemodynamic responses and cardiac rhythm. Ninety children, aged 1-3 years, undergoing day-case adenoidectomy were randomly allocated to three groups: group TS received thiopentone 5 mg kg-1 and suxamethonium 1.5 mg kg-1, group H 5 Vol.% halothane and group PA alfentanil 10 micrograms kg-1 and propofol 3 mg kg-1 for induction of anaesthesia. No anti-cholinergics were used. Holter-monitoring of the heart rate and rhythm was started at least 15 min before induction of anaesthesia and continued until 3 min after intubation. Tracheal intubation was performed by an anaesthetist blinded to the induction method and judged as excellent, moderate or poor according to ease of laryngoscopy, position of vocal cords and incidence of coughing after intubation. Tracheal intubation was successful at the first attempt in all children in groups TS and H and but only in 80% in group PA (P = 0.001). Intubating conditions were excellent in 22 (73%), 22 (73%) and one (3%) of the patients in groups TS, H and PA, respectively (P = 0.001). Cardiac dysrhythmias (supraventricular extrasystole or junctional rhythm) occurred in two (7%) patients in groups PA and H each (NS). Bradycardia occurred in 0 (0%), four (14%) and six (21%) children in groups TS, H and PA, respectively (P = 0.007 PA vs. TS, P = 0.03 H vs. TS). In conclusion, induction of anaesthesia with propofol 3 mg kg-1 and alfentanil 10 micrograms kg-1 without neuromuscular block did not provide acceptable intubating conditions in children 1-3 years, although it preserved arterial pressure better than thiopentone/suxamethonium or halothane. Cardiac dysrhythmias were few regardless of the induction method.

Topics: Adenoidectomy; Alfentanil; Ambulatory Surgical Procedures; Anesthesia; Anesthetics, Combined; Anesthetics, Inhalation; Anesthetics, Intravenous; Arrhythmias, Cardiac; Blood Pressure; Child, Preschool; Electrocardiography, Ambulatory; Female; Halothane; Heart Rate; Hemodynamics; Humans; Infant; Intubation, Intratracheal; Male; Neuromuscular Depolarizing Agents; Propofol; Succinylcholine; Thiopental

In a double-blind study the effect of esmolol and alfentanil on the QT interval of the ECG corrected by the heart rate (QTc), heart rate and arterial pressure during anaesthetic induction was studied in 59 oxycodone- and atropine-premedicated ASA class I-(II) patients with a mean age of 26 yr (range 15-50 yr). The patients were randomly allocated to one of the four groups: saline, esmolol 2 mg.kg-1, esmolol 3 mg.kg-1 or alfentanil 0.03 mg.kg-1. Both doses of esmolol prevented the prolongation of the QTc interval after thiopental and suxamethonium, but not after laryngoscopy and intubation. Alfentanil prevented the prolongation of the QTc interval following thiopental, suxamethonium and laryngoscopy but not after intubation. Esmolol did not prevent the increase in the heart rate and arterial pressure in response to laryngoscopy and intubation. No cardiovascular responses to laryngoscopy and intubation occurred in the patients treated with alfentanil. No cardiac arrhythmias occurred in the esmolol 3 mg.kg-1 group, whereas the frequency of ventricular ectopic beats was 40% in the saline group and 13-20% in the other groups.

Topics: Adolescent; Adrenergic beta-Antagonists; Adult; Alfentanil; Anesthesia; Anesthetics, Intravenous; Arrhythmias, Cardiac; Blood Pressure; Double-Blind Method; Electrocardiography; Heart Rate; Humans; Intubation, Intratracheal; Laryngoscopy; Middle Aged; Propanolamines; Succinylcholine; Thiopental

It is common practice to administer atropine before a first dose of succinylcholine in infants and children. However, the administration of succinylcholine without atropine has not been investigated in children. This study was designed to compare cardiovascular changes after the administration of either atropine with succinylcholine or succinylcholine alone. In 41 ASA I or II patients aged from 1 to 12 yr anaesthesia was induced with thiopentone 5 mg.kg-1. Patients were randomly allocated to receive either atropine 20 micrograms.kg-1 and succinylcholine 1.5 mg.kg-1 (n = 20) or succinylcholine 1.5 mg.kg-1 alone (n = 21). Heart rate and rhythm were recorded continuously from two minutes before induction until two minutes after tracheal intubation. Blood pressure was measured non-invasively before and after induction of anaesthesia and both immediately and two minutes after laryngoscopy. One self-limiting episode of bradycardia was recorded during laryngoscopy in a child who received atropine. Heart rate increased in both groups compared with baseline values (108 +/- 25), with a greater increase in patients who had received atropine (150 +/- 13) than in those who had not (128 +/- 18) (P < 0.05). There was no difference in mean arterial pressure or incidence of arrythmias between the two groups. No recorded arrythmias were judged to be clinically important by a cardiologist. The incidence of bradycardia after succinylcholine in the absence of atropine in children aged from 1 to 12 yr appears to be lower than previously estimated. The use of atropine before a single dose of succinylcholine in children deserves to be reconsidered.

Topics: Adjuvants, Anesthesia; Anesthesia, Intravenous; Anesthetics, Intravenous; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Atropine; Blood Pressure; Bradycardia; Child; Child, Preschool; Female; Heart Rate; Humans; Incidence; Infant; Intubation, Intratracheal; Laryngoscopy; Male; Neuromuscular Nondepolarizing Agents; Succinylcholine; Thiopental

Seventy-five healthy patients were randomly allocated to receive thiopentone, thiopentone/ketamine or ketamine for induction of anaesthesia for elective Caesarean section. Thiopentone resulted in the most pronounced and ketamine in the smallest drop in blood pressure, while the combination induced only moderate haemodynamic changes. Intra-operative awareness occurred in one patient in the thiopentone group, six of the ketamine patients had nightmares, and one patient of the combination group reported pleasant dreams but no awareness. The muscle tone of neonates in the thiopentone group was more reduced than in neonates in the other two groups. Infants delivered after uterine incision-to-delivery intervals exceeding 3 min more often had Apgar scores < 7 than those delivered in less than 3 min.

Topics: Adult; Anesthesia, Intravenous; Anesthesia, Obstetrical; Apgar Score; Arrhythmias, Cardiac; Awareness; Blood Pressure; Cesarean Section; Dreams; Drug Combinations; Female; Fetal Blood; Heart Rate; Humans; Infant, Newborn; Ketamine; Muscle Contraction; Pregnancy; Thiopental

The incidence and intensity of muscle fasciculations as well as the occurrence of cardiac arrhythmias following succinylcholine were evaluated in 36 premedicated children (1.0-5.7 years) after intravenous induction with thiopentone or after inhalation induction with isoflurane (3.75 vol-% in 70% nitrous oxide in oxygen). The study was randomized. In the thiopentone group, fasciculations were seen in all children and in the isoflurane group in 5 of 18 children (P < 0.001). The median of the duration of fasciculations was 15 s with a minimum of 5 s and maximum of 36 s (1st quartile 9 s and 3rd quartile 20 s) in the thiopentone group and 0 (0-15) s with a 1st quartile of 0 and a 3rd quartile of 3 s in the isoflurane group (P < 0.001). No cardiac arrhythmias were noted in either group. In conclusion, isoflurane in nitrous oxide inhibits succinylcholine-induced muscle fasciculations in children.

Topics: Anesthesia, Inhalation; Anesthesia, Intravenous; Arrhythmias, Cardiac; Child, Preschool; Fasciculation; Female; Heart Rate; Humans; Infant; Intubation, Intratracheal; Isoflurane; Male; Nitrous Oxide; Succinylcholine; Thiopental; Time Factors

Sixteen ASA class II or III male patients (aged, 52 to 66 years) undergoing elective cardioversion were randomly assigned to receive either thiopental or etomidate according to an observer-blinded, parallel study design. The appropriate drug was administered in 2-mL aliquots every 15 seconds until the patient no longer responded to verbal commands, at which time cardioversion was attempted. The total dose for induction was 0.22 +/- 0.2 mg/kg and 3.2 +/- 0.4 mg/kg for etomidate and thiopental, respectively. The cardiorespiratory data after induction were evaluated for maximal percent change from baseline. The baseline heart rate was 106 +/- 6 beats/min and 98 +/- 8 beats/min for the etomidate and thiopental groups, respectively (mean +/- SEM). The heart rate decreased 5% after induction with etomidate and increased 7% with thiopental (P less than 0.05). The baseline mean arterial pressure (MAP) was 96 +/- 3 mm Hg and 105 +/- 11 mm Hg for the etomidate and thiopental groups, respectively (mean +/- SEM). The MAP decreased 4% with etomidate and 3% with thiopental. Respiratory rate was significantly increased by 22% after etomidate compared with a 22% decrease in respiratory rate with thiopental (P less than 0.05). Seven of eight patients in the thiopental group required only one countershock, whereas four of eight patients in the etomidate group required only one shock. One patient in each group could not be successfully cardioverted. Recovery time and clinical side effects were similar between groups except for mild myoclonus in the etomidate group. Titration to effect of either etomidate or thiopental provided satisfactory anesthesia for elective cardioversion in hemodynamically stable patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aged; Anesthesia, Intravenous; Arrhythmias, Cardiac; Atrial Fibrillation; Atrial Flutter; Electric Countershock; Etomidate; Humans; Male; Middle Aged; Prospective Studies; Thiopental

Elective cardioversion is a short procedure performed under general anesthesia for the treatment of cardiac dysrhythmias. Selection of the anesthetic agent is important, because a short duration of action and hemodynamic stability are required. Forty-four patients scheduled for elective cardioversion in the coronary care unit were studied prospectively. All patients were randomly assigned, according to the last digit of their clinical record number, to receive one of the four anesthetic agents studied: group 1, 12 patients who received 3 mg/kg of sodium thiopental; group 2, 10 patients who received 0.15 mg/kg of etomidate; group 3, 12 patients who received 1.5 mg/kg of propofol; and group 4, 10 patients who received 0.15 mg/kg of midazolam. All patients also received 1.5 micrograms/kg of fentanyl 3 minutes before induction. All four drugs provided satisfactory anesthesia for cardioversion and there were no major complications. Midazolam produced a more prolonged duration of effect and more interindividual variability. Propofol was associated with hypotension and a higher incidence of apnea, and its duration of action was similar to that of etomidate or thiopental. Etomidate produced myoclonus and pain on injection; however, it was the only agent that did not decrease arterial blood pressure. Thiopental reduced blood pressure but otherwise seemed an appropriate anesthetic for this procedure. In conclusion, all four anesthetic agents were acceptable for cardioversion, although their pharmacological differences suggest specific indications for individual patients.

Topics: Adult; Aged; Anesthesia, Intravenous; Arrhythmias, Cardiac; Atrial Fibrillation; Atrial Flutter; Electric Countershock; Etomidate; Female; Humans; Male; Midazolam; Middle Aged; Propofol; Prospective Studies; Thiopental

In a randomized open study, 120 healthy female patients were included. For short gynaecological procedures they were anaesthetized with either propofol 2.5 mg X kg-1 (n = 60) or thiopentone 5 mg X kg-1 (n = 60) in combination with nitrous oxide/oxygen (67%/33%). Supplementary doses of propofol (10-20 mg) or thiopentone (25-50 mg) were given when necessary during the procedure. Induction characteristics for propofol and thiopentone 1 min after start of induction were similar. Propofol seemed to have a more depressant effect than thiopentone on the circulatory response to anaesthesia. Recovery times from the end of the operative procedure until the patients opened their eyes on command and were orientated were shorter in the propofol patients compared to the thiopentone patients. In the propofol group, patients recalled discomfort on injection more often than patients anaesthetized with thiopentone. Otherwise, the side-effects were similar in both groups. We conclude that propofol is similar to thiopentone in its anaesthetic qualities during induction and maintenance of short anaesthetic procedures. Propofol was associated with a more rapid emergence from anaesthesia than thiopentone.

Topics: Anesthesia, Intravenous; Anesthetics; Arrhythmias, Cardiac; Dilatation and Curettage; Female; Hemodynamics; Humans; Pain; Phenols; Propofol; Thiopental

The occurrence of cardiac arrhythmias and changes in pulse rate and blood pressure during mask anaesthesia with enflurane was investigated in 92 patients with special reference to the influence of atropine (0.01 mg kg-1 5 min before anaesthesia) and thiopental. The average duration of anaesthesia was a little less than 1 h in all four groups. More than five ventricular extrasystoles occurred in one patient (38 min after atropine). Supraventricular (mainly nodal) arrhythmias were significantly (P less than 0.005) more common in the atropine groups (15/45) than in the non-atropine groups (4/47). Following atropine, heart rate increased by about 25 beats min-1, whereas only very slight increases were seen in the non-atropine groups. Blood pressure fell at the induction but was almost back to normal at the end of anaesthesia. Blood pressure was unaffected by atropine. Slightly lower values of blood pressure were suggested in the thiopental groups, whereas thiopental did not modify cardiac rhythm or pulse rate. Suction of the pharynx was necessary in only one patient. In conclusion, the present study does not support the routine administration of atropine before enflurane anaesthesia with or without thiopental induction.

Topics: Adolescent; Adult; Aged; Anesthesia, Inhalation; Arrhythmias, Cardiac; Atropine; Blood Pressure; Clinical Trials as Topic; Enflurane; Heart Rate; Hemodynamics; Humans; Male; Middle Aged; Preanesthetic Medication; Pulse; Random Allocation; Thiopental

The effects of glycopyrrolate and atropine given prior to thiopental-N2O-halothane anesthesia on bradyarrhythmias associated with the administration of succinylcholine were studied and compared. Sixty healthy adult patients were allocated at random to one of three groups. Three minutes before induction of anesthesia with thiopental (4 to 5 mg/kg) one group received glycopyrrolate, 0.0045 mg/kg IV, the second group, glycopyrrolate, 0.008 mg/kg IV, and the third group, atropine, 0.009 mg/kg IV. Succinylcholine, 1 mg/kg of body weight, was given 1 minute and 6 minutes after the conclusion of the thiopental injection. ECG monitoring was continuous, and serum K+ levels as well as PaO2 and paCO2 were repeatedly measured. In all three groups patients were adequately and equally protected against serious bradyarrhythmias following the second dose of succinylcholine by atropine and glycopyrrolate in the doses used.

Topics: Adult; Anesthesia; Arrhythmias, Cardiac; Atropine; Female; Glycopyrrolate; Halothane; Heart Rate; Humans; Male; Middle Aged; Nitrous Oxide; Preanesthetic Medication; Pyrrolidines; Succinylcholine; Thiopental

To study the mechanism of dysrhythmias during microlaryngoscopy, heart rate-corrected QT-times (QTc) were measured in three different methods of anaesthesia. A balanced anaesthesia was induced by Althesin in 96 patients, or by thiopentone in 68 patients. Halothane anaesthesia was induced by Althesin in 23 patients. In all groups the mean QTc-time was significantly longer during the manipulation of vocal cords than before the induction of anaesthesia. Dysrhythmias are also most common during the procedure. With the Althesin-halothane combination, however, the prolongation of QTc-time was most pronounced: Control X +/- SE 408.4 +/- 5.5 msec, manipulation 432.3 +/- 6.7 msec, p less than 0.001. Among those patients who had dysrhythmias during the procedure, only the patients in the Althesin-halothane group had significantly longer QTc-time than before anaesthesia. In patients with supra-ventricular dysrhythmias, differences of QTc-time did not reach significant level. Significant prolongation of QTc-time occurred in patients with ventricular ectopic beats (p less than 0.05) and junctional rhythm (p less than 0.02) but only in the Althesin-halothane group.

Topics: Adult; Alfaxalone Alfadolone Mixture; Anesthesia; Arrhythmias, Cardiac; Drug Combinations; Electrocardiography; Female; Halothane; Heart Rate; Humans; Laryngoscopy; Male; Middle Aged; Thiopental

Eighty healthy adult patients randomly allocated to four groups received pancuronium 0.01, 0.015, 0.02 mg kg-1 or gallamine 0.3 mg kg-1 i.v. 3 min before induction. Just before induction of anaesthesia, the patients were examined for signs and symptoms of neuromuscular blockade. After induction of anaesthesia with thiopentone, suxamethonium 1.5 mg kg-1 was administered i.v. Five minutes later the second dose was injected. No serious arrhythmia was seen in any of the four groups following the repeated dose of suxamethonium. However, the highest dose of pancuronium (0.02 mg kg-1) caused an unacceptably high frequency of partial neuromuscular blockade.

Topics: Adolescent; Adult; Anesthesia, General; Arrhythmias, Cardiac; Drug Administration Schedule; Female; Gallamine Triethiodide; Halothane; Humans; Male; Middle Aged; Nitrous Oxide; Pancuronium; Premedication; Succinylcholine; Thiopental

Continuous ECG recording (Holter technique) was carried out in 25 patients undergoing similar ophtalmological surgery for retinal detachment. The patients were selected at random and divided into two groups. Premedication (alimemazine 25 mg. atropine 0.5 mg given one hour before the operation) and induction (penthiobarbital 4 mg.kg-1 and succinylcholine iodide 1 mg.kg-1) were given in the same way. General anaesthesia was maintained in Group I (n = 12) with halothane and in group II (n = 13) using neuroleptanalgesia. There was no significant difference in the percentage of arrhythmias between the two groups. There was a remarkablly high prevalence of sinus bradycardia and ventricular pauses (8/25). The respective role of atropine and of retrobulbar local anaesthesia in prevention is discussed in the light of data from the literature. If arrhythmias occurring at the time of intubation are included, the total percentage of rhythm disturbances was 80 p. 100 (20/25).

Topics: Arrhythmias, Cardiac; Atropine; Bradycardia; Electrocardiography; Humans; Retinal Detachment; Succinylcholine; Thiopental; Time Factors; Trimeprazine

The effect of barbiturates on cardiac rate and rhythm during halothane anesthesia without intubation was studied in a triple-blind, randomized trial with 28 patients. The test group was premedicated with pentobarbital and induced with thiopental, while the control group was anesthetized with halothane and nitrous oxide only. There was a significant preponderance of sinus-bradycardia and supraventricular disturbances in the control group. It is concluded that the use of barbiturates is advantageous because of their ability to suppress enhanced vagal tone.

Topics: Adult; Aged; Anesthesia, General; Arrhythmias, Cardiac; Blood Pressure; Carbon Dioxide; Halothane; Heart Rate; Humans; Middle Aged; Pentobarbital; Preanesthetic Medication; Thiopental

Three groups of 50 patients were anaesthetized with diazepam 0.32 mg/kg or thiopentone 3.7 mg/kg or propanidid 4.6 mg/kg for elective carfioversion. Propanidid caused more hypotension than diazepam or thiopentone. Apnoea was most frequent following thipentone and excitatory side-effects were most prominent following propanidid; the electric countershock worsened the excitatory phenomena. The success rate of conversion was higher in the diazepam group than in the other groups, but the difference was not statistically significant. Diazepam failed to produce amnesia in about 33% of the patients. Thiopentone is suitable and pleasant for cardioversion. Diazepam is recommended in poor-risk patients and in emergency situations.

Topics: Adult; Aged; Amnesia; Anesthesia, General; Apnea; Arrhythmias, Cardiac; Blood Pressure; Cardiac Complexes, Premature; Diazepam; Electric Countershock; Female; Heart Rate; Humans; Male; Middle Aged; Propanidid; Thiopental

A technique of nebulizing lidocaine in the upper airways was developed and its effectiveness in preventing cardiovascular responses to laryngoscopy and intubation was documented. In ten pre-treated patients the average percentage-rise in systolic blood pressure was 10.3 per cent and there were no arrhythmias. The pulse rate increased by 16.8 per cent. In ten control patients, the systolic blood pressure increased by 56 per cent and the incidence of arrhythmias was 40 per cent. The pulse rate increased by 38.8 per cent. The significance and application of these results is discussed and compared to other available methods. The opinion is expressed that the effect of the aerosol, especially as it relates to the suppression of arrhythmias, is partly due to systemic absorption of lidocaine.

Topics: Aerosols; Aged; Arrhythmias, Cardiac; Blood Pressure; Carbon Dioxide; Clinical Trials as Topic; Electrocardiography; Halothane; Humans; Hypertension; Intubation, Intratracheal; Laryngoscopy; Lidocaine; Male; Middle Aged; Nitrous Oxide; Oxygen; Potassium; Pulse; Thiopental

Topics: Anesthesia, Intravenous; Arrhythmias, Cardiac; Atropine; Cardiac Complexes, Premature; Electric Countershock; Hemodynamics; Humans; Injections, Intramuscular; Preanesthetic Medication; Prevalence; Randomized Controlled Trials as Topic; Thiopental

We aimed to investigate whether mitochondrial ATP-sensitive potassium (mitoKATP) channels play any role on cardiovascular effects of thiopental (TP) or ketamine (K) anesthesia in rats.. mitoKATP channels are the end-effectors of cardioprotection induced by some anesthetics. TP and K are the most frequently used anesthetics with their own cardiovascular effects in experimental studies. To the best of our knowledge, there is no study investigating the cardiovascular effects of TP and K associated with mitoKATP channels.. The experimental groups: TP control, K/Xylazine (X) control, TP+5-hydroxydecanoate (5-HD; mitoKATP channel blocker) and K/X+5-HD. Mean arterial blood pressure (MABP), heart rate (HR) and standard limb lead II ECG were recorded and arrhythmia parameters were evaluated.. Blockage of mitoKATP channels by 5-HD increased MABP and decreased HR in the TP+5-HD and K/X+5-HD groups, respectively. 5-HD caused an increase in ventricular ectopic beat (VEB) incidence. Moreover, VEB incidence was significantly different in TP+5-HD (100%) than K/X+5-HDgroup (66.6%) and ventricular tachycardia was only seen in TP+5-HD (incidence was 88.3%).. mitoKATP channels play different roles in influencing cardiovascular effects of K/X and TP anesthesia in rats. The differences in hemodynamic parameters and arrhythmia scores of these anesthetics should be considered when they are used in an experimental study associated with mitoKATP channels (Fig. 3, Ref. 35).

Topics: Anesthetics, Dissociative; Anesthetics, Intravenous; Animals; Arrhythmias, Cardiac; Arterial Pressure; Cardiovascular System; Decanoic Acids; Electrocardiography; Heart Rate; Hydroxy Acids; Ketamine; Male; Potassium; Potassium Channel Blockers; Potassium Channels; Rats; Thiopental

To investigate the influence of thiopental (85 mg/kg, intraperitoneally (ip)), and ketamine+xylazine (ketamine 75 mg/kg and xylazine 8 mg/kg, ip) anesthesia on the incidence and duration of ischemia/reperfusion-induced arrhythmias.. Myocardial ischemia was induced by a 6-min ligation of the left anterior descending coronary artery, followed by a 6-min reperfusion. Measurements were taken of the incidence and duration of ventricular arrhythmias, the mean arterial blood pressure and heart rate, and the pressure rate-product (as an.index of myocardial oxygen consumption).. The arrhythmia score and the incidence of ventricular fibrillation and tachycardia were significantly decreased in the ketamine+xylazine-anesthetized rats compared with the thiopental-anesthetized group (arrhythmia score: 2.0 ± 2.1 versus 3.7 ± 1.2, P < 0.05). The heart rate was significantly lower in the ketamine+xylazine group during the entire experiment, whilst the pressure-rate product was also significantly lower in the ketamine+xylazine group at different time points of the ischemia and reperfusion periods.. Ketamine+xylazine anesthesia has a strong antiarrhythmic effect and an apparent depressive action on the heart rate and the myocardial oxygen consumption index. Therefore, ketamine+xylazine anesthesia is not appropriate for the evaluation of possible antiarrhythmic agents. Thiopental anesthesia is preferable to ketamine+xylazine anesthesia in the in vivo ischemia-reperfusion arrhythmia model.

Topics: Anesthetics, Combined; Anesthetics, Intravenous; Animals; Arrhythmias, Cardiac; Blood Pressure; Heart Rate; Ketamine; Myocardial Reperfusion Injury; Oxygen Consumption; Rats, Wistar; Thiopental; Xylazine

Despite earlier research studying the influence of anesthetics in arrhythmia models, a lot of controversy remains. The aim was to compare the influence of three anesthetics (60 mg/kg thiopental, 1200 mg/kg urethane, 60 mg/kg pentobarbital intraperitoneally) on ventricular arrhythmias and to combine it with measured hemodynamic parameters to find the most suitable agent for such experiments.. In the model of ischemia- and reperfusion-induced arrhythmias in Sprague-Dawley rats, after left anterior descending coronary artery occlusion (7 minutes) and reperfusion (15 minutes), the following parameters have been measured or calculated: mortality index; ventricular fibrillation and tachycardia incidence and duration; systolic, diastolic, and mean arterial blood pressure; heart rate; myocardial index of oxygen consumption; and plasma creatine kinase concentration.. Evident depressive action of urethane on heart rate, blood pressures, and myocardial index of oxygen consumption should be reason enough to exclude it from use in such studies. Pentobarbital had no effect on arrhythmias, whereas thiopental was antiarrhythmic.. Pentobarbital is the most suitable anesthetic offering stable hemodynamic values during arrhythmia studies. These hemodynamic values, which were similar to physiological values in awake rats, the long arrhythmia duration during reperfusion and approximately 50% mortality index are crucial parameters for evaluating antiarrhythmic drugs.

Topics: Adjuvants, Anesthesia; Anesthetics, Intravenous; Animals; Arrhythmias, Cardiac; Blood Pressure; Disease Models, Animal; Heart Rate; Male; Myocardial Reperfusion Injury; Oxygen Consumption; Pentobarbital; Rats; Rats, Sprague-Dawley; Thiopental; Urethane

Drug-induced torsade de pointes (TdP) arrhythmias can readily be induced in anesthetized dogs with remodeled hearts [chronic complete atrioventricular block (CAVB) dogs]. Similar studies in conscious CAVB dogs reveal lower TdP incidences. Regulations forced us to reconsider our anesthetic regimen, which consist of pentobarbital followed by halothane (P + H). We investigated the relevance of anesthesia for this enhanced susceptibility (part 1) and compared 3 anesthetic regimens (part 2).. Part 1-Ten CAVB dogs paced from the high septum at 1000 milliseconds were challenged with dofetilide (25 microg x kg(-1) x 5 min(-1)) twice: once under anesthesia and once awake. Anesthesia consisted of P + H (n = 5) and thiopental maintained by isoflurane (T + I). Part 2-In CAVB dogs (n = 6) with spontaneous idioventricular rhythm, the electrophysiological and arrhythmogenic consequences of different anesthetic regimens (P + H, T + I, and P + I) were serially compared.. Part 1-In paced dogs, dofetilide-induced TdP was higher under anesthetized than in conscious circumstances, with the more severe outcome seen after T + I as compared with P + H or control (2x): 5/5, 2/5, 0/5, and 0/5, respectively; P < 0.05. Part 2-Electrophysiologically, T accelerated idioventricular rhythm, increased QTc, and transiently induced polymorphic ventricular tachycardias in 2 of 6 dogs. This was not seen after P. At 120 minutes (end of the preparation), QTc increase was highest after T + I, intermediate with P + I, and the smallest after P + H. Dofetilide in combination with T + I induced the most severe arrhythmogenic outcome.. Thiopental anesthesia causes arrhythmias sec, whereas anesthesia in general predisposes for drug-induced TdP in the CAVB dog. In combination with dofetilide, T + I has a more arrhythmic outcome than P + I or P + H.

Topics: Anesthesia; Animals; Arrhythmias, Cardiac; Atrioventricular Block; Dogs; Female; Halothane; Heart Block; Isoflurane; Male; Phenethylamines; Sulfonamides; Thiopental; Torsades de Pointes

The objective of this study was to assess the type and frequency of cardiac dysrhythmias occurring after routine ovariohysterectomy or orchidectomy in young, healthy dogs by using 2 anesthetic protocols (group I: propofol and isoflurane; group II: thiopental and halothane). Fifty dogs under 2 years of age, judged to be clinically normal by physical examination and standard electrocardiography, were evaluated by using 24-hour ambulatory electrocardiography. The most common dysrhythmias in the postoperative period were 2nd degree atrioventricular block (44%), ventricular premature complexes (44%), and atrial premature complexes (32%). For study purposes, more than 100 ventricular or atrial premature complexes per 24 hours, or any occurrence of R-on-T phenomenon, ventricular or atrial tachycardia were classified as clinically significant arrhythmias. Significant arrhythmias were observed in 9 dogs in the postoperative period, 5 of which were in group I and 4 in group II. All of these dogs were under 1 year of age. The R-on-T phenomenon occurred in 4 dogs in group II and 1 dog in group I. Results from this study show that significant arrhythmias, including R-on-T phenomenon, can occur in the perioperative period in young, healthy dogs undergoing routine surgeries with both protocols used.

Topics: Animals; Animals, Newborn; Arrhythmias, Cardiac; Dog Diseases; Dogs; Electrocardiography, Ambulatory; Female; Halothane; Hypnotics and Sedatives; Isoflurane; Male; Orchiectomy; Ovariectomy; Postoperative Complications; Postoperative Period; Propofol; Random Allocation; Thiopental; Time Factors

Diabetics with cardiovascular autonomous neuropathy (CAN) can show severe hypotension during the course of anaesthesia. To improve the safety of anaesthesia, pre-operative evaluation of this concomitant disorder is recommended. The conventional test battery described by Ewing and Clarke to diagnose CAN is relatively time-consuming and complex. The aim of this study was to evaluate whether patients at risk could be reliably identified with less diagnostic effort.. Fifty patients with diabetes mellitus undergoing an ophthalmosurgical procedure were investigated. To evaluate their cardiovascular reflex status, the following tests were performed one day before surgery: determination of heart rate variation (HRV) under deep respiration (6 breaths/min), and the response of heart rate (max/min 30:15 ratio) and blood pressure after getting up from a supine position. Anaesthesia was induced with thiopental and fentanyl and maintained with enflurane/N (2)0; vecuronium was administered for tracheal intubation. Patients whose systolic blood pressure fell below 90 mm Hg during the induction phase were assigned to Group H (hypotensive), the remaining patients to Group N (non-hypotensive). The groups were compared regarding the pre-operatively collected variables.. The demographic data were comparable in the two groups with exception of the length of diabetes. Regarding blood pressure reaction during orthostatic load, there was no significant difference between the groups. In contrast, the parameters of HRV under deep respiration (with exception of the "mean circular resultant") and the max/min 30 : 15 ratio were significantly lower in patients of Group H than in Group N. The best differentiation between the groups offered the E/I ratio (= quotient resulting from the longest R-R interval during expiration (E) and the shortest R-R interval during inspiration (I) under deep breathing) as a measure of respiratory sinus arrhythmia. The incidence of hypotension during anaesthetic induction in patients with a normal E/I ratio was 8.7 %, but in patients with a pathologically reduced E/I ratio 51.9 % ( P = 0.0019). The sensitivity of this test concerning hypotension that occurred was 87.5 %, the specificity 61.7 %.. The available results prove the close connection between the pre-operatively measured breadth of respiratory sinus arrhythmia and blood pressure response during anaesthetic induction. Patients at risk of hypotension can be identified reliably and quickly during pre-operative screening with the help of a single, simple test procedure.

Topics: Adult; Aged; Anesthesia; Anesthetics, Inhalation; Anesthetics, Intravenous; Arrhythmias, Cardiac; Blood Pressure; Diabetes Mellitus; Enflurane; Female; Fentanyl; Hemodynamics; Humans; Hypotension, Orthostatic; Intubation, Intratracheal; Male; Middle Aged; Monitoring, Intraoperative; Ophthalmologic Surgical Procedures; Predictive Value of Tests; Risk; Thiopental

Atrial tachyarrhythmias (AT) frequently complicate the perioperative period. Alcohol intoxication is a recognized causative factor for dysrrhythmias. We studied the effects of propofol and thiopental on atrial electrophysiology and vulnerability to AT in a closed-chest porcine model in which AT are facilitated by ethanol.. Thirty-eight pigs were randomly assigned to thiopental (T-group, n=19) or propofol (P-group n=19). All animals were assigned to undergo a right atrial electrical stimulation protocol (RASP) at baseline. Thirty pigs were assigned to undergo additional RASP during ethanol infusion, while the remaining eight were assigned to undergo additional RASP during saline infusion (control group). We analysed effective refractory period (ERP), and intra-atrial conduction interval (ICI) (between atrial sites 4 cm apart), at several cycle lengths (CL).. There were no significant differences at baseline. During ethanol infusion, propofol produced a greater rate-dependent decrease in excitability, manifested by a longer minimum paced CL with 1:1 atrial capture: 145 (11) vs 164 (27) ms in the T- and P-group, respectively (P=0.01). Propofol was associated with a greater rate-related slowing in conduction: difference between ICI at CL of 300 ms and ICI at minimum CL: 30 ms in P-group and 22 ms in T-group (P<0.03). In the P-group we observed a longer duration of induced arrhythmias (145 (131) vs 74 (91) s, P<0.03) and a higher proportion with atrial flutter (AFl) (76 vs 19%, P<0.001).. Propofol in this model was more arrhythmogenic than thiopental, as manifested by a longer duration of induced arrhythmias, particularly AFI.

Topics: Alcoholic Intoxication; Anesthetics, Intravenous; Animals; Arrhythmias, Cardiac; Atrial Flutter; Atrial Function, Right; Disease Models, Animal; Electrophysiology; Ethanol; Propofol; Random Allocation; Swine; Thiopental

Halothane more so than isoflurane potentiates an alpha1-adrenoceptor (alpha1-AR)-mediated action of epinephrine that abnormally slows conduction in Purkinje fibers and may facilitate reentrant arrhythmias. This adverse drug interaction was further evaluated by examining conduction responses to epinephrine in combination with thiopental and propofol, which "sensitize" or reduce the dose of epinephrine required to induce arrhythmias in the heart, and with etomidate, which does not, and responses to epinephrine with verapamil, lidocaine, and l-palmitoyl carnitine, a potential ischemic metabolite.. Action potentials and conduction times were measured in vitro using two microelectrodes in groups of canine Purkinje fibers stimulated at 150 pulses/min. Conduction was evaluated each minute after exposure to 5 microm epinephrine (or phenylephrine) alone or with the test drugs. Changes in the rate of phase 0 depolarization (Vmax) and the electrotonic spread of intracellular current were measured during exposure to epinephrine with octanol to evaluate the role of inhibition of active and passive (intercellular coupling) membrane properties in the transient depression of conduction velocity.. Lidocaine (20 microm) and octanol (0.2 mm) potentiated alpha1-AR-induced conduction depression like halothane (0.4 mm), with maximum depression at 3-5 min of agonist exposure, no decrease of Vmax, and little accentuation at a rapid (250 vs. 150 pulses/min) stimulation rate. Thiopental (95 microm), propofol (50 microm), and verapamil (2 microm) similarly potentiated epinephrine responses, whereas etomidate (10 microm) did not. Between groups, the decrease of velocity induced by epinephrine in the presence of (10 microm) l-palmitoyl carnitine (-18%) was significantly greater than that resulting from epinephrine alone (-6%; 0.05

Topics: Action Potentials; Adrenergic alpha-Agonists; Anesthetics; Animals; Arrhythmias, Cardiac; Dogs; Drug Synergism; Epinephrine; Etomidate; Fatty Acids; Halothane; Heart; In Vitro Techniques; Lidocaine; Neural Conduction; Octanols; Palmitoylcarnitine; Propofol; Purkinje Fibers; Receptors, Adrenergic, alpha-1; Thiopental; Verapamil

Arrhythmia due to ischaemia and/or reperfusion is an important problem, especially in open heart surgery and for patients with ischaemic heart diseases undergoing non-cardiac surgery. This experimental study is planned to evaluate the effects of midazolam on ischaemia and/or reperfusion-induced arrhythmias by comparison with thiopentone in two sets of experiments (n = 20 for every group). In total ischaemia-reperfusion experiments, hearts were perfused in constant pressure conditions. In the control group, after a stabilisation period, perfusion was totally stopped for 30 min and the hearts were reperfused for 10 min. For the experimental groups, hearts were pretreated for 5 min with either 10-6 mol 1-1 midazolam or 10-5 mol 1-1 thiopentone before total ischaemia and reperfused for 10 min with the same concentrations of the drugs. In low-flow ischaemia-reperfusion experiments, hearts were perfused at a constant flow of 10 ml g-1 heart per min initially. In the control group, after a stabilisation period, perfusion rate was decreased successively 1 ml g-1 heart per min for 10 min (mild ischaemia) and to 0.2 ml g-1 heart per min for another 10 min (severe ischaemia). The ischaemic hearts were then reperfused for an additional 10 min at a flow rate of 10 ml g-1 heart per min. Electrogram recordings were evaluated before ischaemia and at the 5th and 10th min of mild ischaemia, severe ischaemia and reperfusion. Midazolam, 10-6 mol 1-1, or thiopentone, 10-5 mol 1-1, were added to the perfusion solution in the midazolam and thiopentone groups, respectively. In these two groups, hearts were perfused according to perfusion rates mentioned above in the control group. As a commonly used i.v. anaesthetic, thiopentone was arrhythmogenic for hearts exposed to ischaemia-reperfusion by increasing ventricular premature beat (% incidences for control, midazolam and thiopental groups in the 10th min of reperfusion were 25, 15 and 65 in total ischaemia-reperfusion experiments, P < 0.01) and ventricular tachycardia (respective % incidences were 0, 5, 25, P < 0.05) incidences, but in our experiments were found out that the new agent midazolam does not have more arrhythmia incidence than the respective control group in any criteria evaluated. None of the agents exerted atrioventricular conductance abnormalities. So we conclude that midazolam is a safe agent for ischaemic hearts and might also be antiarrhythmic and the mechanism of action of this effect remains to be further inv

Topics: Adjuvants, Anesthesia; Anesthetics, Intravenous; Animals; Arrhythmias, Cardiac; Female; Heart; In Vitro Techniques; Male; Midazolam; Myocardial Reperfusion Injury; Rats; Rats, Wistar; Thiopental

Although thiopental is known to potentiate halothane-epinephrine arrhythmias, the precise mechanism of this potentiation is obscure. The authors investigated the comparative role of alpha 1 and beta adrenergic actions in the thiopental-induced potentiation of halothane-epinephrine arrhythmias in dogs. Adult mongrel dogs were anesthetized with halothane alone (1.3%) or thiopental (20 mg kg-1) plus halothane and monitored continuously for systemic arterial pressures and for premature ventricular contractions. The arrhythmogenic doses of phenylephrine and isoproterenol were determined during the two anesthetic methods and the effect of thiopental on the arrhythmogenic action of alpha 1 and beta agonists was examined. Thiopental failed to exert a significant potentiation of arrhythmogenic effect of phenylephrine or isoproterenol, when these agents were administered separately. On the other hand, the potentiation of arrhythmogenicity by thiopental was remarkable in the case of combined administration of both the agonists, that is, thiopental enhanced the synergistic interaction between phenylephrine and isoproterenol for inducing arrhythmias during halothane anesthesia. In addition, the potentiation was more prominent when a low dose of isoproterenol and a high dose of phenylephrine was combined than that when a high dose of isoproterenol and a low dose of phenylephrine was given in combination. The results indicate that thiopental significantly potentiates the arrhythmogenic interaction of alpha 1 and beta adrenergic agonists administered concurrently, although individual potentiation of these agonists is not significant.

Topics: Anesthetics; Animals; Arrhythmias, Cardiac; Dogs; Drug Synergism; Epinephrine; Female; Halothane; Male; Receptors, Adrenergic, alpha-1; Receptors, Adrenergic, beta; Thiopental

In this study, our induction methods of endotracheal anesthesia was evaluated with reference to electrocardiogram, hemodynamic status and arterial blood gas analysis on 153 patients. From the beginning of induction, electrocardiogram was recorded continuously to the completion of intubation. The blood pressure and heart rate were also measured. Arterial blood samples were taken at 40 seconds of apneic period after the mask was removed from the patient's face (CONT group), at 40 seconds of apnea with intratracheal spray (LIDO group), and after intubation following intratracheal spray (INT group). In the electrocardiographic survey, arrhythmias during intubation were rare (1/113, 0.9%). PaCO2 values in INT group showed a significant elevation (+ 14.0 mmHg; p < 0.01) compared to these in CONT group. As a result of careful and gentle induction techniques, the incidence of arrhythmias during intubation was very low. However, an elevation of PaCO2 was not avoidable, even in smooth and successful intubation. In conclusion, the importance of more adequate ventilation coupled with skillful intubation in a shorter period to avoid hypercapnia and arrhythmias is appreciated again in the endotracheal anesthesia for the maxillofacial surgical patients with anatomical airway problems.

Topics: Adult; Anesthesia, Dental; Anesthesia, General; Anesthetics, Inhalation; Anesthetics, Intravenous; Apnea; Arrhythmias, Cardiac; Blood Pressure; Carbon Dioxide; Ethers; Female; Heart Rate; Humans; Intubation, Intratracheal; Isoflurane; Male; Methyl Ethers; Middle Aged; Oxygen; Partial Pressure; Sevoflurane; Thiopental; Time Factors

The authors investigated the role of alpha 1- and beta-adrenoceptors on induction of ventricular arrhythmias during thiopental anesthesia in dogs and compared with that during halothane anesthesia. Throughout this study, arrhythmogenic threshold of epinephrine during thiopental anesthesia was designed to be comparable with that during halothane anesthesia. Phenylephrine, an alpha 1-agonist, and isoproterenol, a beta-agonist, consistently failed to provoke arrhythmias during thiopental or halothane anesthesia. The interaction between phenylephrine and isoproterenol in inducing arrhythmias was synergistic and additive during halothane and thiopental anesthesia, respectively, indicating that adrenoceptor mechanism in thiopental-epinephrine arrhythmias is different from that in halothane-epinephrine arrhythmias. During thiopental anesthesia, incidence of arrhythmias with blood pressure elevation by epinephrine, phenylephrine, or angiotensin II was not different, and increasing heart rate by electrical pacing did not replace isoproterenol in the arrhythmogenic interaction between isoproterenol and phenylephrine. The results indicate that blood pressure elevation due to the combined inotropic action of alpha 1- and beta-adrenoceptor agonists is a critical factor in the genesis of thiopental-epinephrine arrhythmias.

Topics: Adrenergic alpha-Agonists; Adrenergic beta-Agonists; Animals; Arrhythmias, Cardiac; Blood Pressure; Dogs; Drug Synergism; Epinephrine; Female; Halothane; Heart Rate; Male; Receptors, Adrenergic, alpha; Receptors, Adrenergic, beta; Thiopental

The present study was carried out to evaluate the effect of anesthetics on reperfusion arrhythmias. Male Wistar rats (200-300 g) were injected ip with heparin (200 IU), followed by anesthesia with thiopental (40 mg/kg), pentobarbital (30 mg/kg), urethane (1.2 g/kg), either, or halothane and sacrificed by decapitation. The isolated heart (5 to 8 per group) was perfused with Locke solution by the Langendorff method and the left coronary artery was ligated for 10 min. The incidence of reperfusion arrhythmias (100%) was similar in hearts of control and previously anesthetized rats, but the duration of the arrhythmias was significantly increased by anesthesia (5-fold with thiopental, 15-fold with pentobarbital, ether and halothane, and 30-fold with urethane). In hearts taken from unanesthetized rats and perfused with Locke solution containing anesthetics (5-7 per group), the duration of reperfusion arrhythmias decreased with thiopental (0.23 +/- 0.15 min), did not change with pentobarbital (1.14 +/- 0.26 min) and increased with urethane (16.10 +/- 5.60 min). Our results show that anesthetics alter the duration of reperfusion arrhythmias in the isolated rat heart.

Topics: Anesthetics; Animals; Arrhythmias, Cardiac; Male; Myocardial Reperfusion; Pentobarbital; Rats; Rats, Wistar; Thiopental; Urethane

1. The primary aim of this investigation was to ascertain the effects of thiopentone sodium and diethyl ether as anaesthetics on plasma catecholamine levels of Sprague-Dawley and Long-Evans rats. A secondary aim was to investigate the effect of norepinephrine on susceptibility to electrically induced arrhythmia in the Langendorff perfused isolated rat heart. 2. Thiopentone sodium anaesthesia resulted in significantly lower plasma norepinephrine and epinephrine levels when compared with diethyl ether anaesthesia. 3. Long-Evans rats exhibited significantly higher epinephrine levels regarding both anaesthetics in comparison with their Sprague-Dawley counterparts. 4. If plasma catecholamines are an indicator of the level of induced stress then diethyl ether anaesthesia resulted in more stress both of a psychological and physiological origin when compared with thiopentone sodium anaesthesia. 5. Long-Evans rats seem to be more prone to the physiologically-induced component of stress than Sprague-Dawley rats. 6. In isolated hearts, norepinephrine increased susceptibility (P less than 0.002) to electrically induced arrhythmia. This occurred at a concentration corresponding to measured upper levels of total catecholamines in diethyl ether anaesthetised animals.

Topics: Animals; Arrhythmias, Cardiac; Dose-Response Relationship, Drug; Epinephrine; Ether; Heart; Heart Rate; In Vitro Techniques; Male; Norepinephrine; Perfusion; Rats; Rats, Sprague-Dawley; Thiopental

The purpose of this study was to evaluate epinephrine-aminophylline-induced arrhythmias during halothane anaesthesia after induction with thiopentone or midazolam. Ten mongrel dogs were studied during 1 MAC halothane and 50% N2O:O2 anaesthesia while maintaining constant acid-base status. The minimal arrhythmogenic infusion rate of epinephrine (MAIRE) and the corresponding plasma concentration of epinephrine (MAPC) required to produce ventricular arrhythmias before and after aminophylline were higher following induction of anaesthesia with midazolam than with thiopentone (P less than 0.05); the MAIREs decreased stepwise with aminophylline (P less than 0.05). The correlation coefficient between individual MAIREs and MAPCs was 0.93 (P less than 0.001). Epinephrine alone and in combination with aminophylline was less arrhythmogenic after induction with midazolam than with thiopentone.

Topics: Aminophylline; Anesthesia, Inhalation; Anesthesia, Intravenous; Animals; Arrhythmias, Cardiac; Blood Pressure; Dogs; Drug Interactions; Epinephrine; Female; Halothane; Heart Rate; Infusions, Intravenous; Male; Midazolam; Potassium; Thiopental; Time Factors

Previous studies in dogs of anesthetic-epinephrine arrhythmias have used logdose or bracketed epinephrine infusion protocols to determine the arrhythmic dose of epinephrine (ADE) or plasma level of epinephrine at arrhythmias (PCE). Reported logdose ADE values for halothane preceded by thiopental induction (thiopental-halothane) are twice those with the bracket protocol. There are no reported PCE data for the bracket protocol, and neither protocol has been directly compared in the same dogs. Therefore, direct comparisons were made of thiopental-halothane ADE and PCE in seven dogs (group 1). Dogs were induced with thiopental (20 mg/kg), followed by halothane inhalation at end-tidal concentrations equivalent to MAC 1.25. Epinephrine infusion protocols were compared on two weekly test occasions, with the sequence and order of protocol testing randomized. Logdose ADE for four or more ventricular beats within 15 s was 3.92 +/- 0.60 micrograms/kg (mean +/- standard error), higher than the bracket ADE (2.54 +/- 0.34 micrograms/ml) (P less than 0.05). PCE at ADE were similar for both protocols, but six separate infusions of epinephrine were required to establish ADE with the logdose compared to four with the bracket protocol (P less than 0.05). These findings suggested enhanced epinephrine clearance with the logdose protocol. Therefore, five additional but similarly anesthetized dogs (group 2) were tested to determine if physiologic or hemodynamic conditions prior to epinephrine infusions ("initial conditions") were equivalent for both protocols. Protocols were modified to avoid provocation of ventricular arrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Arrhythmias, Cardiac; Dogs; Epinephrine; Female; Halothane; Hemodynamics; Infusions, Intravenous; Male; Random Allocation; Thiopental

This study was designed to assess in vitro the effects of Thiopental alone and Thiopental--Dobutamine association on control and on Diltiazem pretreated papillary muscle. The Diltiazem treatment do not increase the negative inotropic effect of Thiopental but the effect of Dobutamine is less important in pretreated group. The Diltiazem treatment protect to arrhythmogenic action of Thiopental and Thiopental-Dobutamine association.

Topics: Animals; Arrhythmias, Cardiac; Diltiazem; Dobutamine; Drug Interactions; Guinea Pigs; Models, Biological; Myocardial Contraction; Papillary Muscles; Thiopental

The aim of the study was to assess the influence of general anaesthesia on electrocardiographic and arrhythmogenic responses to left anterior descending coronary artery occlusion.. Pigs weighing 18-20 kg were anaesthetised with alpha chloralose 100 mg.kg-1 (n = 9) or thiopentone 30 mg.kg-1 (n = 9) and the arrhythmogenic effects of coronary artery occlusion were examined by sequential electrocardiographic measurements every 5 min and arrhythmia analysis every minute over a 60 min period.. alpha Chloralose predisposed to lower ST segment elevation (analysis of variance for repeated measurements p less than 0.002), less marked epicardial conduction delay (p less than 0.01) with slower progression to monophasic potentials, and in contrast, to a greater number of episodes of ventricular premature beats (p less than 0.005), ventricular tachycardia (51 v 32 episodes), and ventricular fibrillation (6 v 2 pigs) than barbiturate anaesthesia.. alpha Chloralose and barbiturates exerted opposite electrocardiographic and arrhythmogenic effects in a porcine model of acute myocardial ischaemia. Due to its proarrhythmic effect chloralose should probably be used in studies dealing with spontaneous and induced ischaemic arrhythmias.

Topics: Anesthesia, General; Animals; Arrhythmias, Cardiac; Cardiac Complexes, Premature; Chloralose; Coronary Disease; Electrocardiography; Heart; Swine; Thiopental; Ventricular Fibrillation

Anesthesia was induced in 91 children using one of three induction regimens: (a) thiopental, atropine, and succinylcholine (T group); (b) halothane, atropine, and succinylcholine (H group); and (c) halothane, thiopental, atropine, and succinylcholine (H/T group). The incidence of dysrhythmias was significantly greater in the H group (85%) than in the T group (6%) and H/T group (20%). Fewer dysrhythmias occurred in the H/T group compared to the H group despite similarly prolonged QTc intervals in both groups. We conclude that induction of anesthesia with thiopental is appropriate and reduces the incidence of cardiac rhythm disturbances in children and that administration of thiopental to children during induction of anesthesia with halothane, atropine, and succinylcholine may reduce the incidence of cardiac dysrhythmias.

Topics: Anesthesia, General; Anesthesia, Intravenous; Arrhythmias, Cardiac; Atropine; Child; Child, Preschool; Electrocardiography; Halothane; Humans; Infant; Succinylcholine; Thiopental

This study examined the interaction between thiopental and epinephrine in inducing ventricular arrhythmias in dogs. The arrhythmogenic threshold of epinephrine was determined during anesthesia with either halothane alone, thiopental alone, etomidate plus different doses of thiopental, or halothane plus different doses of thiopental. The arrhythmogenic dose and the corresponding plasma concentration of epinephrine during thiopental anesthesia (plasma thiopental concentration: 46-57 micrograms/ml) were 0.77 +/- 0.04 micrograms.kg-1.min-1 and 10.7 +/- 1.5 ng/ml, respectively. During halothane anesthesia (end-tidal: 1.3 MAC) they were 2.59 +/- 0.49 micrograms.kg-1.min-1 and 45.3 +/- 9.2 ng/ml, respectively. The dose-effect relationship for the thiopental action was examined during etomidate plus thiopental and halothane plus thiopental anesthesia. The arrhythmogenic plasma concentration of epinephrine was inversely proportional to the plasma thiopental concentration during both anesthetics. During etomidate plus thiopental anesthesia, at plasma thiopental concentrations of 0, 11.2 +/- 0.83, 20.1 +/- 1.34, and 33.2 +/- 1.95 micrograms/ml, the corresponding epinephrine concentrations were 201.3 +/- 34.3, 142 +/- 19.5, 69.1 +/- 21.2, and 22.7 +/- 4.5 ng/ml. During halothane plus thiopental anesthesia, at plasma thiopental concentrations of 0, 10 +/- 0.86, 18.3 +/- 0.87, and 31.8 +/- 1.05 micrograms/ml, the corresponding epinephrine concentrations were 45.3 +/- 9.2, 34.6 +/- 8.9, 16.2 +/- 1.74, and 15.1 +/- 1.32 micrograms/ml, respectively. These results suggest that thiopental sensitizes the heart to epinephrine in a dose-dependent manner. This sensitizing action of thiopental would in part explain the thiopental potentiation of hydrocarbon anesthetic-epinephrine arrhythmias.

Topics: Anesthetics; Animals; Arrhythmias, Cardiac; Dogs; Dose-Response Relationship, Drug; Drug Synergism; Epinephrine; Etomidate; Female; Halothane; Male; Thiopental

Local anaesthetic systemic toxicity is a rare but often dramatic complication of regional anaesthesia. Convulsions often follow warning signs, easily recognized when looked for; but they may occur from the first. They are rapidly followed by hypoxia and hypercapnia which greatly enhance the risk of severe cardiac depression, mainly with bupivacaine or etidocaine. Thiopentone is able to stop convulsions quickly, but may further depress the cardiovascular system. Diazepam has been shown to be effective in the treatment of local anaesthetic-induced convulsions. It gives less myocardial depression, but is much slower in effect. Midazolam, a new short-acting benzodiazepine, should be the best choice. Should tracheal intubation become necessary, suxamethonium can be used. Indeed, the principal use of these drugs is to make ventilation easier, so as to restore rapidly correct oxygenation. Severe cardiac depression, often leading to cardiac arrest, may occur from the first or after the appearance of convulsions. It generally follows a regional block carried out with bupivacaine. A few antiarrhythmic drugs have been used to treat ventricular arrhythmias, either in experimental studies (lidocaine, bretylium) or after clinical accidents (lidocaine). Their efficacy and innocuity have to be proved before they can be proposed to treat these accidents. Bradycardia only needs treatment with atropine when it causes severe haemodynamic disturbances. When cardiac arrest occurs, cardiopulmonary resuscitation must be carried out; its mainstays are: oxygen, sodium bicarbonate, adrenaline, calcium and perhaps glucagon. This must be continued for a long time, as late successes have been published.

Topics: Anesthetics, Local; Anti-Anxiety Agents; Arrhythmias, Cardiac; Benzodiazepines; Calcium Gluconate; Epinephrine; Glucagon; Heart Arrest; Heart Diseases; Humans; Seizures; Succinylcholine; Thiopental

The haemodynamic response to tracheal intubation was compared in 303 patients in whom anaesthesia was induced with either thiopentone 4 mg/kg, etomidate 0.3 mg/kg or propofol 2.5 mg/kg, with and without fentanyl 2 micrograms/kg. There was after propofol alone a significant decrease in arterial blood pressure, which did not increase above control values after intubation. Significant increases in arterial pressure followed intubation in patients induced with thiopentone or etomidate alone. Increases in heart rate occurred with all agents after laryngoscopy. The use of fentanyl resulted in arterial pressures lower than those after the induction agent alone, and in an attenuation, but not abolition of the responses to laryngoscopy and intubation.

Topics: Adolescent; Adult; Anesthesia, Intravenous; Anesthetics; Arrhythmias, Cardiac; Etomidate; Female; Hemodynamics; Humans; Intraoperative Complications; Intubation, Intratracheal; Male; Middle Aged; Phenols; Propofol; Thiopental

Topics: Adult; Anesthesia, Intravenous; Arrhythmias, Cardiac; Blood Pressure; Fiber Optic Technology; Heart Rate; Humans; Intubation, Intratracheal; Laryngoscopy; Light; Thiopental; Time Factors

The central nervous toxicity of local anaesthetics has long been thought to be limited to the generalized tonicoclonic convulsions which follow the appearance of such symptoms as sleepiness, tingling of the lips, slurred speech, numbness, etc. Also the central nervous system was considered to be more sensitive than the cardiovascular system. However, recent experimental studies would seem to indicate that at least the more potent local anaesthetics, such as bupivacaine, have deleterious effects on parts of the brain other than the cerebral hemispheres. This may point to an involvement of the central nervous system (the amygdala and vasopressor areas of the floor of the fourth ventricle) in the pathogenesis of the hypotension and arrhythmias which may be seen at the same time as central nervous system signs of systemic toxicity. This is important for the treatment of such accidents: should a convulsion occur alone, sodium thiopentone, a muscle relaxant and a benzodiazepine, with oxygen and assisted breathing, will be the treatment; should an arrhythmia occur, its treatment should also include an anticonvulsant drug, such as a benzodiazepine. The prophylactic use of benzodiazepines should also be encouraged.

Topics: Anesthetics, Local; Arrhythmias, Cardiac; Benzodiazepines; Brain Stem; Central Nervous System; Humans; Seizures; Thiopental

Topics: Adult; Anesthesia; Arrhythmias, Cardiac; Electrocardiography; Female; Fentanyl; Heart; Humans; Hysterectomy; Isoflurane; Long QT Syndrome; Propranolol; Thiopental; Vecuronium Bromide

Epinephrine-induced dysrhythmias were studied in 19 dogs anesthetized with 1.25 MAC enflurane or isoflurane, or the same preceded by thiopental (20 mg/kg). In 11 (group 1) dogs, thiopental reduced the dose of epinephrine required for production of ventricular ectopy, bigeminy and tachycardia with enflurane, and only ventricular tachycardia with isoflurane (P less than 0.05). Thiopental potentiation of epinephrine-induced dysrhythmias with enflurane lasted 4 hr after induction. In eight (group 2) dogs, the arrhythmic dose (ADE in microgram/ml) and plasma level of epinephrine (PLE in ng/ml) for four or more ventricular extrasystoles in 15 sec were determined in the same animal under each of the four test conditions. ADE and PLE values (X +/- SEM) were, respectively, enflurane, 9.1 +/- 1.0 and 141 +/- 24 (8/8 dogs); enflurane-thiopental, 5.0 +/- 0.6 and 63 +/- 16 (8/8 dogs); isoflurane, 28.3 and 330 (1/7 dogs); and isoflurane-thiopental, 15.2 +/- 2.8 and 265 +/- 59 (5/7 dogs). In addition, thiopental had no effect on plasma epinephrine levels reached during epinephrine infusions with 1.0 (enflurane only), 2.0 (enflurane, isoflurane) and 4.0 micrograms X kg-1 X min-1 (isoflurane only). Nor were epinephrine levels reached during enflurane or enflurane-thiopental different from those reached during isoflurane or isoflurane-thiopental. It is concluded that thiopental potentiates several types of epinephrine-induced ventricular dysrhythmias with enflurane, but only ventricular tachycardia with isoflurane. Furthermore, isoflurane or isoflurane-thiopental were less sensitizing than enflurane or enflurane-thiopental. Finally, neither thiopental nor the anesthetic agents affected plasma epinephrine levels reached during epinephrine infusions lasting 3 min.

Topics: Animals; Arrhythmias, Cardiac; Blood Gas Analysis; Blood Pressure; Cardiac Complexes, Premature; Dogs; Drug Interactions; Enflurane; Epinephrine; Female; Heart Ventricles; Infusions, Parenteral; Isoflurane; Male; Methyl Ethers; Potassium; Thiopental

We have used immature commercial swine (13-25 kg) successfully in a variety of experimental cardiopulmonary surgical procedures in our laboratories since 1981. Multiple drug anesthetic protocols using barbiturates, narcotics, paralytic and antiarrhythmic agents have been employed in over 400 procedures per year. Complications, including fatal cardiac arrhythmias, have been greatly reduced by anesthetic protocols and surgical procedures developed through experience.

Topics: Acepromazine; Anesthesia; Animals; Arrhythmias, Cardiac; Bradycardia; Cardiopulmonary Bypass; Cardiovascular Surgical Procedures; Female; Fentanyl; Halothane; Heart Transplantation; Male; Pancuronium; Pentobarbital; Pneumonectomy; Succinylcholine; Swine; Thiamylal; Thiopental; Ventricular Fibrillation

Electrocardiographic (ECG) changes were studied in 82 adult patients with a mean age of 49 years undergoing microlaryngoscopy. The patients were pretreated with practolol 0.15 mg/kg i.v. 5 min before induction of anaesthesia with thiopental. Anaesthesia was maintained with nitrous oxide in oxygen, fentanyl and suxamethonium-infusion. ECG changes occurred in 49% of the patients before anaesthesia and procedure. Pre-existing ECG changes increased or new changes occurred in 39% of the patients during intubation and in 38% during the procedure. The most common preanaesthetic ECG changes were flat or negative T-wave (18%), sinus tachycardia (13%), ischaemic S-T segment depression (8.5%) and intraventricular conduction disturbance (8.5%). ECG changes during intubation were sinus tachycardia (16%), ventricular ectopic beats (12%), supraventricular ectopic beats (10%) and ischaemic S-T segment depression (10%). The most common changes during microlaryngoscopy were supraventricular ectopic beats (16%), T-wave flattening or inversion (15%), ischaemic S-T segment depression (11%) and sinus bradycardia (10%). In all patients ECG changes disappeared without any special treatment. Unlike our earlier identical study without practolol pretreatment, neither sinus tachycardia nor junctional rhythm occurred during microlaryngoscopy in the present study. The results suggest that practolol pretreatment before microlaryngoscopy is especially useful when sinus tachycardia and junctional rhythm should be avoided.

Topics: Adult; Anesthesia, General; Arrhythmias, Cardiac; Electrocardiography; Female; Fentanyl; Humans; Intubation, Intratracheal; Laryngoscopy; Male; Middle Aged; Nitrous Oxide; Practolol; Preanesthetic Medication; Succinylcholine; Thiopental

The cardiovascular and electroencephalographic (EEG) effects of thiopental were investigated, with and without preceding global brain ischemia (GBI). Four groups of pigtailed monkeys were used: Group I received thiopental 90 mg/kg over 1 h after 16 min GBI. Group II received thiopental 90 mg/kg over 1 h without preceding brain ischemia. Group III received 90 mg/kg over 1, 3, 6, or 8 h with varying infusion rates and no brain ischemia. Group IV, after 16 min GBI, received thiopental 90 mg/kg over 12 h with a gradually reduced infusion rate, keeping thiopental serum levels around 120-140 mumol X l-1 throughout the infusion. Large doses of thiopental (Group II) produced serious cardiovascular side-effects. With co-existing brain ischemia (Group I), these side-effects were much worse; five of six animals not receiving lidocaine prophylaxis suffered circulatory arrest. A prolongation of the Q-T interval on the electrocardiogram may be of pathogenetic importance. In contrast, lower thiopental blood levels, sufficient to depress the EEG to burst suppression or isoelectricity, were well tolerated with and without preceding brain ischemia (Groups IV and III).

Topics: Animals; Arrhythmias, Cardiac; Brain; Brain Ischemia; Electrocardiography; Electroencephalography; Female; Heart Arrest; Heart Block; Hemodynamics; Macaca nemestrina; Male; Thiopental

Epinephrine-induced ventricular arrhythmias were studied in 8 dogs anesthetized at weekly intervals with halothane (1.09% end-tidal concentration) preceded by thiamylal or thiopental (20 mg/kg of body weight). Lead II, bundle of His and high right atrial electrograms, and femoral artery and airway pressures were recorded. Epinephrine was infused in logarithmically spaced increasing rates (initial rate = 0.25 micrograms/kg/min) for a maximum of 2.5 minutes. The maximal (greater than or equal to 4 ventricular premature depolarizations within 15 s of each other) and minimal (all other ventricular or junctional rhythms) arrhythmogenic doses were calculated (infusion rate X time to arrhythmia). The mean (+/- SD) minimal arrhythmogenic dosages for the thiamylal-halothane, thiopental-halothane, and halothane-only groups were 1.84 +/- 0.66, 1.83 +/- 0.64, and 3.69 +/- 1.32 micrograms/kg, respectively; the mean (+/- SD) maximal arrhythmogenic dosages were 2.32 +/- 0.77, 3.37 +/- 1.30, and 8.86 +/- 4.40 micrograms/kg, respectively, with no change after 4 hours of anesthesia. During infusion of the maximal arrhythmogenic dosages, the mean infusion of the maximal arrhythmogenic dosages, the mean percentage increase in serum K+ for thiamylal-halothane, thiopental-halothane, and halothane-only groups was 33 +/- 14%, 31 +/- 13%, and 38 +/- 18%, respectively.

Topics: Anesthesia, General; Animals; Arrhythmias, Cardiac; Blood Pressure; Dog Diseases; Dogs; Drug Synergism; Epinephrine; Halothane; Heart Rate; Heart Ventricles; Thiamylal; Thiopental

Barbiturate, nitrous oxide, and oxygen are commonly used by the oral and maxillofacial surgeon to anesthetize the ambulatory oral surgery patient. The authors report three cases of ventricular dysrhythmia occurring from surgical stimulation during nitrous oxide-oxygen-thiopental anesthesia. These dysrhythmias were most likely mediated via direct neural stimulation of cardiac sympathetic nerves. Concomitant with adrenergic stimulation, a rise in the arterial plasma norepinephrine level was documented, along with an increase in the rate-pressure product. Immediate recognition and treatment of ventricular dysrhythmia is mandatory to preclude further serious cardiovascular complications or death.

Topics: Anesthesia, Dental; Anesthesia, General; Arrhythmias, Cardiac; Heart Conduction System; Humans; Neurotransmitter Agents; Nitrous Oxide; Oxygen; Sympathetic Nervous System; Thiopental

Plasma levels of epinephrine which correspond to the arrhythmogenic doses were determined during halothane, enflurane, and pentobarbital anesthesia in the dog. The arrhythmogenic dose was established by a series of 3-min infusion of epinephrine at 10-min intervals. The mean values of the arrhythmogenic doses and the corresponding plasma levels of epinephrine were: 2.18 micrograms X kg-1 X min-1 and 38.7 ng/ml during halothane; 11.43 micrograms X kg-1 X min-1 and 206.3 ng/ml during enflurane; and 15.27 micrograms X kg-1 X min-1 and 296.5 ng/ml during pentobarbital anesthesia. The arrhythmogenic plasma levels of norepinephrine during halothane anesthesia was nearly the same as that of epinephrine.

Topics: Anesthesia, General; Animals; Arrhythmias, Cardiac; Dogs; Enflurane; Epinephrine; Female; Halothane; Male; Norepinephrine; Pentobarbital; Thiopental

Epinephrine-induced arrhythmias were studied in 14 dogs (Group 1) anesthetized with halothane alone (1.09% end-tidal), and on another occasion, at the same halothane concentration following intravenous thiopental (20 mg/kg). Surface (Lead II), catheter His bundle and high right atrial electrocardiograms, and airway and femoral arterial pressures were recorded. Graded doses of epinephrine (EPI-least dose 0.25 microgram . kg-1 . min-1) were infused over five minutes, but terminated sooner if ventricular tachycardia occurred (maximal sensitization). Sensitizing EPI doses (microgram . kg-1) were calculated (dose X time to arrhythmia) for: Shift in or wandering atrial pacemaker (SAP-WAP), atrial ectopy (At Ect), A-V dissociation (AVD), and ventricular ectopy, bigeminy, or tachycardia (V Ect, V Bigem, V Tach). With halothane alone, SAP-WAP occurred at the least dose of EPI followed by At Ect, AVD, V Ect, V Bigem, and V Tach in order of increasing EPI dose. Following thiopental, EPI doses for AVD, V Ect, V Bigem, and V Tach were reduced, as well as EPI dose differences for At Ect, AVD, V Ect, and V Bigem. In an additional seven dogs (Group 2), anesthesia was induced with thiopental (20 mg/kg) followed by halothane (1.09% end-tidal). These animals were observed for arrhythmias during graded EPI infusions at 1-2 h and 3-4 h following thiopental. Sensitizing EPI doses for SAP-WAP and V Tach were similar at each time period. The authors concluded that with halothane and increasing EPI dose, sensitization constitutes a spectrum of arrhythmias, beginning with atrial and progressing to severe ventricular arrhythmias. Thiopental reduces the EPI dose needed for AVD and ventricular, but not atrial, arrhythmias. It also reduces the EPI dose discrepancies for atrial and ventricular arrhythmias.

Topics: Animals; Arrhythmias, Cardiac; Blood Gas Analysis; Dogs; Drug Synergism; Epinephrine; Female; Halothane; Heart Ventricles; Hemodynamics; Male; Thiopental; Time Factors

Although lidocaine is commonly accepted as an anti-arrhythmic drug, it can also be used intravenously as an anesthetic agent. The author focuses on how lidocaine can be used as an integral part of the anesthetic itself for patients with cardiac arrhythmias, particularly premature ventricular contractions.

Topics: Aged; Anesthesia, General; Anesthesia, Inhalation; Anesthesia, Intravenous; Arrhythmias, Cardiac; Cardiovascular System; Electrocardiography; Humans; Lidocaine; Male; Nitrous Oxide; Thiopental

Myocardial infarction was produced in dogs and cats by occlusion of the left anterior descending coronary artery. Arrhythmia was present in dogs but not in cats 6 to 48 h after occlusion. The absence of arrhythmia in cats was not due to persistent myocardial depressant effects of anaesthesia administered during surgery. Studies in cats with surgically-induced heart block revealed multiple ventricular pacemakers but no change in average ventricular rate following coronary occlusion. These results suggest that sinus overdrive, although not elevated compared with the dog, is sufficient to suppress arrhythmia in the cat. Further, since small dogs developed significantly less arrhythmia than large dogs, heart size may be an additional factor in explaining the absence of arrhythmia in the cat.

Topics: Animals; Arrhythmias, Cardiac; Atrioventricular Node; Body Weight; Cats; Disease Models, Animal; Dogs; Female; Heart; Heart Conduction System; Heart Ventricles; Male; Myocardial Infarction; Organ Size; Thiopental; Vagus Nerve

The efficacy of electroimpulsive therapy with low energy discharges (up to 50 joules) in various paroxysmal arrhythmias was studied. A mild tranquilizer, seduxen (diazenam), was used as the anesthetic. Electroimpulsive therapy with low-energy discharges was found to produce a high effect in ventricular tachycardia and atrial flutter but a poor restorative effect in atrial fibrillation. The possibility of successful anesthesia with seduxen in electrical cardioversion of paroxysmal disorders of cardiac rhythm is concretized.

Topics: Adult; Aged; Anesthesia; Arrhythmias, Cardiac; Atrial Fibrillation; Atrial Flutter; Diazepam; Electric Countershock; Electrocardiography; Female; Humans; Male; Middle Aged; Propanidid; Tachycardia, Paroxysmal; Thiopental

The purpose of this study was to examine the effects of pharmacologic alterations of adrenergic terminating mechanisms by cocaine, tropolone, aminophylline, and ketamine on the ability of epinephrine to induce arrhythmias during halothane-nitrous oxide anesthesia in dogs. Because the first three drugs inhibit intraneuronal uptake of catecholamines, extraneuronal catechol-O-methyl transferase (COMT), and phosphodiesterase, respectively, they might be expected to potentiate epinephrine-induced arrhythmias. To evaluate this possibility, the authors devised a technique for determining the minimal arrhythmic dosage of epinephrine that permitted graded assessment of changes in the sensitivity of the heart to epinephrine-induced arrhythmias. When the first three drugs were administered to the same dog in the order listed at intervals of 60 minutes, they sequentially increased the ability of epinephrine to induce arrhythmias. Ketamine, according to several investigators, also appears to block reuptake of catecholamines, and when studied was also found to enhance the arrhythmogenicity of epinephrine. The extent of enhancement was comparable to that seen with cocaine. These results indicate that drugs like cocaine and ketamine that interfere with intraneuronal uptake can facilitate the development of epinephrine-induced arrhythmias and that the successive pharmacologic interference of intraneuron uptake, COMT, and phosphodiesterase leads to a stepwise increase in the arrhythmogenicity of epinephrine.

Topics: Aminophylline; Anesthesia, Endotracheal; Animals; Arrhythmias, Cardiac; Blood Pressure; Cocaine; Cycloheptanes; Dogs; Dose-Response Relationship, Drug; Epinephrine; Female; Halothane; Heart Rate; Ketamine; Male; Receptors, Adrenergic; Receptors, Adrenergic, beta; Thiopental; Tropolone

The incidences of electrocardiographic (ECG) changes during microlaryngoscopy under halothane anaesthesia were compared by using Althesin and thiopentone as induction agents. During the procedure the most common ECG change in both groups was junctional rhythm, which occurred in 37% of the patients in the Althesin group and in 29% of the patients in the thiopentone group. The next most common changes in the Althesin group were: ventricular ectopic beats (22%), ischaemic S-T segment depression (14%), and T wave flattening or inversion (14%); those in the thiopentone group were ventricular ectopic beats (18%) and rapidly ascending S-T segment depression (12%). As well as during the procedures, some ECG changes were registered in both groups during intubation. ECG changes disappeared without any special treatment after manipulation of the vocal cords or after intubation. There was no statistically significant difference in the total incidence of dysrhythmias between the Althesin and thiopentone groups, but the types of dysrhythmias were different in the two groups. There were more lower nodal rhythms, less serious ectopic beats and more ischaemic S-T segment depression in the Althesin group than in the thiopentone group. The results suggest that Althesin is useful and superior to thiopentone in patients with a tendency to develop serious ventricular ectopic beats, whereas in patients with heart and coronary arterial disease, Althesin is inferior to thiopentone and should be used with care.

Topics: Adolescent; Adult; Aged; Alfaxalone Alfadolone Mixture; Anesthesia, Inhalation; Arrhythmias, Cardiac; Child; Electrocardiography; Female; Halothane; Heart; Humans; Laryngoscopy; Male; Middle Aged; Pregnanediones; Thiopental

The effects of epinephrine (5 microgram/kg of body weight) on ten unanesthetized sheep were experimentally tested: all sheep displayed serious arrhythmias. Sheep anesthetized with thiopental and thiopental/halothane combination displayed cardiac arrhythmias of the order of 10% and 20% respectively. Challenge injections of epinephrine (5 microgram/kg of body weight) to ten sheep anesthetized with thiopental, and to the same number of animals after 45 minutes of anesthesia with thiopental/halothane, produced serious arrhythmias. However, following preanesthetic treatment with acepromazine maleate (0.5 mg/kg) to 15 sheep, serious arrhythmias were prevented in all of them when they were given arrhythmic doses of epinephrine.

Topics: Acepromazine; Anesthesia; Animals; Arrhythmias, Cardiac; Drug Synergism; Epinephrine; Female; Halothane; Heart; Male; Preanesthetic Medication; Sheep; Thiopental

The effects of dobutamine, a new catecholamine, have been studied during anaesthesia with halothane, halothane and nitrous oxide and alphaprodine. Renal blood flow is increased by dobutamine as are mean arterial pressure and heart rate. The increase in rate is less marked during alphaprodine anaesthesia than when halothane is administered. Dobutamine may prove a useful agent in the management of acute circulatory failure but it is capable of inducing dysrhythmias under the conditions of these experiments.

Topics: Alphaprodine; Animals; Arrhythmias, Cardiac; Catecholamines; Dobutamine; Dogs; Halothane; Heart Rate; Kidney; Nitrous Oxide; Pancuronium; Regional Blood Flow; Thiopental; Tubocurarine

Topics: Adolescent; Adult; Aged; Anesthesia, General; Arrhythmias, Cardiac; Atropine; Blood Pressure; Diazepam; Drug Combinations; Drug Compounding; Female; Humans; Injections, Intravenous; Lung Compliance; Male; Meperidine; Middle Aged; Preanesthetic Medication; Promethazine; Pulse; Respiration; Succinylcholine; Thiopental; Tubocurarine

Topics: Anesthetics; Arrhythmias, Cardiac; Blood Pressure; Child; Drainage; Drug Combinations; Ear, Middle; Female; Heart Rate; Humans; Hydroxysteroids; Male; Nausea; Pediatrics; Preanesthetic Medication; Pregnanediones; Pulse; Reflex; Respiration; Thiopental; Tympanic Membrane; Vomiting

Topics: Anesthesia, Inhalation; Anesthesia, Local; Arrhythmia, Sinus; Arrhythmias, Cardiac; Atropine; Bupivacaine; Digitalis Glycosides; Drug Combinations; Drug Synergism; Electrocardiography; Halothane; Heart; Heart Conduction System; Heart Rate; Humans; Morphine; Nitrous Oxide; Preanesthetic Medication; Pulse; Scopolamine; Succinylcholine; Thiopental

Topics: Adolescent; Adult; Aged; Anesthesia, Inhalation; Anesthetics; Arrhythmias, Cardiac; Blood Pressure; Chlorine; Electroencephalography; Epinephrine; Ethers; Female; Fluorine; Heart Rate; Humans; Hydrocarbons, Halogenated; Intubation, Intratracheal; Male; Middle Aged; Morphine; Nitrous Oxide; Oxygen; Phenylephrine; Preanesthetic Medication; Respiration; Shivering; Thiopental; Time Factors; Tubocurarine

Topics: Acidosis; Acute Kidney Injury; Anemia; Anesthesia; Anesthesia, Epidural; Anesthesia, Spinal; Antihypertensive Agents; Arrhythmias, Cardiac; Heart Failure; Hepatitis; Humans; Hyperkalemia; Hypertension; Hypocalcemia; Hyponatremia; Kidney Failure, Chronic; Nausea; Preanesthetic Medication; Seizures; Thiopental; Uremia; Vomiting

Topics: Adolescent; Adult; Aged; Anesthesia, General; Anesthetics; Arrhythmias, Cardiac; Blood Pressure; Carbon Dioxide; Cardiac Surgical Procedures; Child; Female; Gallamine Triethiodide; Heart Rate; Humans; Hypotension; Intubation, Intratracheal; Male; Methohexital; Middle Aged; Neuromuscular Nondepolarizing Agents; Oxygen; Pancuronium; Thiopental; Toxiferine; Tubocurarine

Topics: Adolescent; Adult; Anesthesia, General; Anesthetics; Arrhythmias, Cardiac; Chlorprothixene; Female; Hemodynamics; Humans; Hypertension; Male; Methoxyflurane; Middle Aged; Phenoxybenzamine; Pheochromocytoma; Postoperative Care; Preanesthetic Medication; Premedication; Propranolol; Succinylcholine; Thiopental

Topics: Adolescent; Adult; Aged; Anesthesia, Intravenous; Arrhythmias, Cardiac; Ethanol; Eye Diseases; Humans; Male; Middle Aged; Reflex; Thiopental

Topics: Anesthetics; Animals; Arrhythmias, Cardiac; Blood Circulation; Blood Pressure; Cats; Epinephrine; Female; Halothane; Heart Rate; Ketones; Male; Pregnanes; Propanidid; Thiopental

Topics: Androstanes; Arrhythmias, Cardiac; Female; Humans; Intubation, Intratracheal; Male; Neuromuscular Nondepolarizing Agents; Piperidines; Succinylcholine; Thiopental

Topics: Amodiaquine; Animals; Arrhythmias, Cardiac; Cyclopropanes; Dogs; Electrocardiography; Epinephrine; Heart Atria; Heart Conduction System; Heart Septum; Thiopental; Vagus Nerve

Topics: Adult; Aged; Anesthesia, General; Arrhythmias, Cardiac; Ataxia; Atropine; Blood Pressure; Diazepam; Electrocardiography; Electroconvulsive Therapy; Electromyography; Female; Headache; Heart; Humans; Injections, Intravenous; Male; Mental Disorders; Middle Aged; Pulse; Respiration; Succinylcholine; Thiopental

Topics: Adult; Aged; Anesthesia, General; Arrhythmias, Cardiac; Atropine; Benperidol; Female; Fentanyl; Halothane; Heart Rate; Humans; Injections, Intravenous; Male; Meperidine; Middle Aged; Neostigmine; Nitrous Oxide; Oxygen; Tachycardia; Thiopental; Tubocurarine

Topics: Anesthesia, Endotracheal; Animals; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Atropine; Blood Pressure; Dogs; Epinephrine; Gallamine Triethiodide; Heart Conduction System; Heart Rate; Nitrous Oxide; Succinylcholine; Thiopental; Tubocurarine

Topics: Adolescent; Adult; Age Factors; Aged; Anesthesia, General; Arrhythmias, Cardiac; Benperidol; Bradycardia; Coronary Disease; Cysts; Electrocardiography; Halothane; Humans; Jaw Fractures; Lidocaine; Male; Methohexital; Middle Aged; Propanidid; Propranolol; Surgery, Oral; Tachycardia; Thiopental; Tooth Extraction

Topics: Anesthesia, Inhalation; Arrhythmias, Cardiac; Diazepam; Electric Countershock; Halothane; Humans; Nitrous Oxide; Preanesthetic Medication; Thiopental

Topics: Arrhythmias, Cardiac; Blood Pressure; Diazepam; Electric Countershock; Humans; Male; Thiopental

Topics: Anesthesia; Anesthetics; Arrhythmias, Cardiac; Atrial Flutter; Atropine; Electric Countershock; Electric Stimulation Therapy; Electroconvulsive Therapy; Humans; Mental Disorders; Methohexital; Propanidid; Succinylcholine; Tachycardia; Thiopental; Ventricular Fibrillation

Topics: Animals; Arrhythmias, Cardiac; Blood Pressure; Female; Heart; Heart Rate; Horses; Immobilization; Injections, Intravenous; Male; Oxygen; Propranolol; Respiration; Succinylcholine; Tachycardia; Thiopental

Topics: Adult; Anesthesia, Intravenous; Arrhythmias, Cardiac; Humans; Male; Nitrous Oxide; Oxygen; Respiratory Insufficiency; Thiopental

Topics: Anesthesia, Intravenous; Animals; Arrhythmias, Cardiac; Barbiturates; Dogs; Female; Heart; Heart Conduction System; Heart Ventricles; Male; Thiamylal; Thiopental

Topics: Animals; Arrhythmias, Cardiac; Dogs; Drug Synergism; Epinephrine; Halothane; Heart; Hypercapnia; Hyperventilation; Rabbits; Thiopental

Topics: Anesthesia, General; Anesthetics; Arrhythmias, Cardiac; Diazepam; Electric Countershock; Humans; Methods; Nitrous Oxide; Piperidines; Preanesthetic Medication; Thiopental

Topics: Acetylcholine; Animals; Arrhythmias, Cardiac; Cerebral Cortex; Female; Heart Atria; Heart Ventricles; Male; Myocardium; Pentobarbital; Rats; Thiopental

Topics: Anesthesia, General; Arrhythmias, Cardiac; Atropine; Electrocardiography; Electroconvulsive Therapy; Humans; Injections, Intravenous; Injections, Subcutaneous; Methohexital; Oxygen; Oxygen Inhalation Therapy; Preanesthetic Medication; Respiration; Respiration, Artificial; Succinylcholine; Thiopental; Time Factors

Topics: Amnesia; Arrhythmias, Cardiac; Diazepam; Electric Countershock; Female; Humans; Injections, Intravenous; Male; Meperidine; Methods; Middle Aged; Thiopental

Topics: Analysis of Variance; Anesthesia, General; Apnea; Arrhythmias, Cardiac; Blood Specimen Collection; Bronchoscopy; Carbon Dioxide; Catheterization; Cyanosis; Female; Humans; Hypercapnia; Hyperventilation; Lidocaine; Male; Middle Aged; Oxygen; Oxygen Consumption; Positive-Pressure Respiration; Succinylcholine; Thiopental; Vocal Cords

Topics: Anesthesia, General; Arrhythmias, Cardiac; Atropine; Cardiac Surgical Procedures; Humans; Hyperventilation; Methoxyflurane; Nitrous Oxide; Oxygen; Postoperative Complications; Preanesthetic Medication; Scopolamine; Tachycardia; Thiopental; Thoracic Arteries; Tubocurarine; Ventricular Fibrillation

Topics: Animals; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Autonomic Nervous System; Dogs; Electrocardiography; Epinephrine; Female; Hydrocarbons; Male; Phenothiazines; Thiopental

Topics: Animals; Arrhythmias, Cardiac; Consciousness; Halothane; Heart; Heart Rate; Horses; Oxygen; Propranolol; Sensory Receptor Cells; Stimulation, Chemical; Succinylcholine; Sympathetic Nervous System; Tachycardia; Thiopental

Topics: Anesthetics; Arrhythmias, Cardiac; Electrocardiography; Female; Humans; Male; Tachycardia; Thiopental

Topics: Anesthesia, Inhalation; Arrhythmias, Cardiac; Blood Gas Analysis; Cardiac Catheterization; Electrocardiography; Halothane; Heart; Humans; Nitrous Oxide; Thiopental

Topics: Arrhythmias, Cardiac; Electric Countershock; Female; Humans; Middle Aged; Thiopental

Topics: Adult; Anesthesia, General; Arrhythmias, Cardiac; Bronchoscopy; Cardiac Complexes, Premature; Electrocardiography; Female; Humans; Intubation, Intratracheal; Male; Middle Aged; Oxygen; Preanesthetic Medication; Succinylcholine; Tachycardia; Thiopental

Topics: Action Potentials; Animals; Arrhythmias, Cardiac; Atrial Function; Drug Antagonism; Electrophysiology; Epinephrine; Female; Heart; Heart Atria; Heart Rate; Male; Membrane Potentials; Norepinephrine; Pentobarbital; Rabbits; Thiopental

Topics: Adult; Aged; Anesthesia; Arrhythmias, Cardiac; Electric Countershock; Female; Humans; Male; Middle Aged; Thiopental

Topics: Adult; Aged; Anesthesia; Anesthetics, Intravenous; Arrhythmias, Cardiac; Electrocardiography; Electroconvulsive Therapy; Female; Humans; Male; Methohexital; Middle Aged; Mood Disorders; Schizophrenia; Thiopental

Topics: Administration, Intravenous; Adolescent; Anesthesia; Anesthesia, Intravenous; Arrhythmias, Cardiac; Child; Electric Countershock; Geriatrics; Humans; Thiopental

Topics: Animals; Arrhythmias, Cardiac; Blood Pressure; Bradycardia; Dogs; Electric Stimulation; Electrocardiography; Heart Rate; Isoproterenol; Pharmacology; Research; Tachycardia; Thiamylal; Thiopental; Vagus Nerve

Topics: Adolescent; Adult; Aged; Anesthesia, General; Arrhythmias, Cardiac; Blood Pressure; Cardiovascular System; Electrocardiography; Halothane; Humans; Intubation, Intratracheal; Middle Aged; Muscles; Quaternary Ammonium Compounds; Succinylcholine; Thiopental

Topics: Adult; Anesthesia, Inhalation; Arrhythmias, Cardiac; Ethyl Ethers; Evaluation Studies as Topic; Halothane; Humans; Middle Aged; Spirometry; Thiopental

Topics: Adolescent; Anesthesia; Anesthesia, Intravenous; Arrhythmias, Cardiac; Cardiac Complexes, Premature; Child; Electrocardiography; Geriatrics; Humans; Intubation; Intubation, Intratracheal; Succinylcholine; Surgical Procedures, Operative; Tachycardia; Thiopental; Ventricular Fibrillation

Topics: Anesthesia; Anesthesia, Intravenous; Arrhythmias, Cardiac; Catecholamines; Electrocardiography; Norepinephrine; Pharmacology; Physiology; Tachycardia; Thiopental; Toxicology

Topics: Arrhythmias, Cardiac; Cyclopropanes; Dogs; Drug Synergism; Electrocardiography; Epinephrine; Pharmacology; Research; Thiopental; Toxicology

Topics: Anesthesia; Anesthesia, Inhalation; Arrhythmias, Cardiac; Barbiturates; Cyclopropanes; Ether; Humans; Nitrous Oxide; Thiopental