benzofurans and Tachycardia--Paroxysmal

Topics: Administration, Oral; Amiodarone; Arrhythmias, Cardiac; Benzofurans; Cardiomyopathy, Hypertrophic; Heart; Heart Conduction System; Humans; Tachycardia, Paroxysmal; Thyroid Diseases; Thyroid Gland; Wolff-Parkinson-White Syndrome

Topics: Adrenergic alpha-Antagonists; Adrenergic beta-Antagonists; Amiodarone; Angina Pectoris; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Benzofurans; Clinical Trials as Topic; Drug Evaluation; Humans; Hypothyroidism; Myocardial Contraction; Oxygen Consumption; Parasympatholytics; Structure-Activity Relationship; Tachycardia, Paroxysmal; Thyroid Gland; Vascular Resistance; Vasodilator Agents; Wolff-Parkinson-White Syndrome

Topics: Adrenergic beta-Antagonists; Aged; Amiodarone; Anti-Arrhythmia Agents; Atrial Fibrillation; Benzofurans; Cardiac Complexes, Premature; Clinical Trials as Topic; Female; Humans; Male; Middle Aged; Tachycardia, Paroxysmal; Time Factors

Topics: Adrenergic alpha-Antagonists; Adrenergic beta-Antagonists; Amiodarone; Angina Pectoris; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Benzofurans; Clinical Trials as Topic; Drug Evaluation; Humans; Hypothyroidism; Myocardial Contraction; Oxygen Consumption; Parasympatholytics; Structure-Activity Relationship; Tachycardia, Paroxysmal; Thyroid Gland; Vascular Resistance; Vasodilator Agents; Wolff-Parkinson-White Syndrome

Repetitive supraventricular tachycardia is an uncommon arrhythmia which usually occurs in patients free of structural heart disease. It is characterized by incessant short salvos of supraventricular tachycardia separated by only one or two normal sinus beats. Therapy with conventional antiarrhythmic drugs is usually ineffective. This report describes three patients with repetitive supraventricular tachycardia in whom evidence for associated sinus node dysfunction was observed. Amiodarone therapy, with ventricular pacing in two patients, has provided effective control of this arrhythmia in all three patients.

Topics: Adult; Aged; Amiodarone; Atrial Fibrillation; Atrial Flutter; Benzofurans; Dose-Response Relationship, Drug; Electrocardiography; Heart Atria; Humans; Male; Middle Aged; Tachycardia, Paroxysmal

In clinically euthyroid subjects on long-term amiodarone therapy free thyroxine (T4) concentrations were increased and free triiodothyronine (T3) levels reduced. There was also a marked increase in reverse T3 in the treated group. These changes are consistent with inhibition of peripheral deiodination of T4 and reverse T3. Despite the rise in T4 serum thyrotrophin (TSH) levels were increased, suggesting an effect of amiodarone on the anterior pituitary. To investigate the interaction of amiodarone with the cellular actions of thyroid hormones we examined the influence of the drug in vitro on the binding of T3 to isolated nuclei prepared from rat anterior pituitary tissue. Amiodarone inhibited the nuclear binding of T3 in a dose dependent fashion. Addition of amiodarone in vitro also stimulated TSH release from cultured rat anterior pituitary cells, consistent with a T3 antagonistic effect. These studies provide evidence for a direct influence of amiodarone on the thyrotroph, mediated via nuclear T3 receptor binding.

Topics: Adult; Aged; Amiodarone; Animals; Arrhythmias, Cardiac; Benzofurans; Cell Nucleus; Coronary Disease; Female; Humans; Male; Middle Aged; Pituitary Gland, Anterior; Protein Binding; Rats; Rats, Inbred Strains; Tachycardia, Paroxysmal; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Topics: Adult; Aged; Amiodarone; Atrioventricular Node; Benzofurans; Electrocardiography; Female; Heart Conduction System; Humans; Male; Middle Aged; Tachycardia, Paroxysmal

Topics: Adolescent; Amiodarone; Benzofurans; Female; Humans; Infusions, Parenteral; Intracranial Pressure; Male; Middle Aged; Pseudotumor Cerebri; Tachycardia, Paroxysmal

Topics: Adult; Amiodarone; Benzofurans; Electrocardiography; Electrophysiology; Female; Humans; Injections, Intravenous; Male; Middle Aged; Tachycardia, Paroxysmal

The Authors evaluated the effectiveness and the tolerance of intravenous Amiodarone in 50 cases of recent onset paroxysmal supraventricular tachyarrhythmias. Fifty consecutive patients, aged 17 to 84 (mean 52 years), presenting with paroxysmal supraventricular tachycardia (PSVT, 33 cases) or atrial flutter (11 cases) or atrial fibrillation (6 cases), were given 300 mg of Amiodarone intravenously within 2 min, followed in 4 patients by 150 mg after 15 min. All patients were monitored for 1 hour; ECG and blood pressure were recorded at fixed times. Within 15 min sinus rhythm was restored in 88% of PSVT, in 27% of atrial flutter and in 17% of atrial fibrillation cases; the other cases of atrial flutter and fibrillation always showed a 48-81% reduction of the average heart rate within 15 min. We have evidenced neither significant modifications of blood pressure and ECG parameters (P-Q, QRS and Q-T duration) nor particular side effects, except for 2 cases in which brief hot flushes were reported. The Authors believe Amiodarone to be an effective and well tolerated drug for the above mentioned arrhythmias, particularly promptly acting in PSVT cases, in whom sinus rhythm was restored within 15 min in 88% and within 1 hour in 100% of the cases.

Topics: Adolescent; Adult; Aged; Amiodarone; Atrial Fibrillation; Atrial Flutter; Benzofurans; Female; Humans; Injections, Intravenous; Male; Middle Aged; Tachycardia, Paroxysmal

Topics: Adult; Aged; Amiodarone; Benzofurans; Drug Resistance; Female; Humans; Male; Middle Aged; Recurrence; Tachycardia, Paroxysmal

Topics: Adult; Amiodarone; Benzofurans; Humans; Hyperthyroidism; Male; Tachycardia, Paroxysmal

In eight patients who had previously responded to treatment with oral amiodarone for prevention of recurrent supraventricular paroxysmal tachycardia, a new regimen of oral amiodarone dosing was evaluated. Each patient received the entire dose, previously taken throughout one week (600 to 1,200 mg), on a single day, once each week. After six weeks on this regimen, all patients were still free of arrhythmias and there were no adverse reactions to the drug. In the first week of the new treatment, amiodarone plasma levels gradually fell from 1.83 mg/l, to 0.48 mg/l, on average. The trough level was similar to that obtained when the drug was given on a daily basis. It is concluded that this new regimen can be used for patients receiving oral amiodarone, and it may be advantageous in improving the compliance of some patients.

Topics: Amiodarone; Benzofurans; Female; Humans; Kinetics; Male; Tachycardia, Paroxysmal

Sixteen patients were examined hemodynamically with echocardiography, calibrated apexcardiography, and systolic time intervals before treatment, after 1 week treatment with amiodarone 600 mg daily and after 2-4 months treatment with 300 mg daily. During the treatment thyroid function was controlled. The echocardiogram showed a small increase in shortening fraction, while left ventricular dimensions did not change significantly. The apexcardiogram revealed minor changes, which could not be interpreted as being due to changes in contractility. The systolic time intervals showed marked decreases in preejection period index and preejection period/left ventricular ejection time. These changes could not be correlated to changes in serum thyroxine, which was the only thyroid parameter to change significantly. The hemodynamic changes during amiodarone treatment were interpreted as mainly being due to a decrease in afterload while possible changes in preload and myocardial contractility were of minor importance.

Topics: Adult; Aged; Amiodarone; Benzofurans; Blood Pressure; Echocardiography; Female; Heart Rate; Hemodynamics; Humans; Kinetocardiography; Male; Middle Aged; Systole; Tachycardia, Paroxysmal; Thyroid Hormones

Topics: Aged; Amiodarone; Benzofurans; Female; Heart Ventricles; Humans; Male; Middle Aged; Tachycardia, Paroxysmal

A study was performed to assess whether plasma and myocardial concentrations of amiodarone correlated with changes on the surface electrocardiogram. Nine patients--seven with angina and two with paroxysmal ventricular tachycardia--were treated with oral amiodarone (200-400 mg daily) for at least nine months before undergoing cardiac surgery. QT intervals were measured from lead II of the surface electrocardiograms recorded before amiodarone treatment and immediately before surgery. Patients with prominent U waves after taking amiodarone were excluded from the study. Plasma and myocardial samples were collected at the beginning of the surgical procedure for estimating plasma and myocardial concentrations using the high performance liquid chromatographic technique. Amiodarone caused a significant lengthening of the QTc interval. There was a good correlation between plasma and myocardial concentrations, and both correlated well with the percentage increase in the QTc interval. Although there was a strong correlation between the dosage given (mg/kg/day) and both plasma and myocardial concentrations, the correlation with the percentage increase in the QTc interval was weaker but still highly significant. Despite previous reports to the contrary, the findings indicate that the plasma concentration of amiodarone does correlate well with the myocardial concentration. The degree of lengthening of the QTc interval may be used clinically to estimate the myocardial concentration of amiodarone.

Topics: Adult; Aged; Amiodarone; Angina Pectoris; Benzofurans; Electrocardiography; Female; Heart; Humans; Male; Middle Aged; Myocardium; Tachycardia, Paroxysmal

The efficacy of amiodarone in the prevention of atrial tachycardia is well recognised. However, there remains some controversy over its use in patients with a basal sinus bradycardia because of the risk of further depression of sinus node function. We studied the effects of acute and chronic amiodarone therapy in 13 patients with paroxysmal supraventricular tachycardia and intercritical sinus bradycardias of between 40 and 50/min. All patients underwent electrophysiological investigation under basal conditions and after 5 mg/kg IV amiodarone. Five patients were excluded from chronic oral amiodarone therapy after IV amiodarone for the following reasons : sinus bradycardia of less than 30/min; sinus node recovery times greater than 2 s; 2nd or 3rd degree sino-atrial block. The other 8 patients were administered oral amiodarone on a long term basis. They were followed up clinically with dynamic ECGs every three months over a period of 1 to 3 years. All symptoms regressed in 6 patients. In one patient, the daily attacks of palpitations decreased to one a week. One patient did not improve. No cases of sino-atrial standstill were observed, although the sinus rate remained unchanged. The results of our study show that amiodarone may be administered for long periods in patients with sinus bradycardia and attacks of paroxysmal supraventricular tachycardia if the dynamic ECG during the waking hours shows a heart rate of no less than 40/min, and if electrophysiological investigations do not show significant depression of sinus node function after acute intravenous administration of the drug.

Topics: Adult; Aged; Amiodarone; Benzofurans; Bradycardia; Female; Humans; Male; Middle Aged; Tachycardia, Paroxysmal

In Wolff-Parkinson-White (WPW) syndrome, the two most commonly occurring arrhythmias are circus movement tachycardia (CMT) and atrial fibrillation (AF). In 70% of patients with clinically documented CMT in whom the arrhythmia could be initiated by programmed electrical stimulation of the heart, the same CMT could still be initiated after long-term oral amiodarone administration. Spontaneous clinical recurrence of the arrhythmia was, however, observed in only 10% of patients. This finding suggests that the beneficial effect of amiodarone on CMT is primarily based on the prevention of the CMT-initiating premature beat. This may also apply to atrioventricular nodal reentrant tachycardia, in which amiodarone is also extremely effective in preventing relapses. The role of amiodarone in other forms of reentrant, or ectopic, supraventricular tachycardias is less well defined. During AF in WPW syndrome, the ventricular rate is related to the duration of the anterograde refractory period of the accessory pathway. Amiodarone prolongs this value, resulting in the reduction of ventricular rate during AF. Unfortunately, in the presence of a short anterograde refractory period of the accessory pathway, amiodarone results in only a small amount of lengthening of this value. In these patients the beneficial effect of amiodarone may primarily be related to the prevention of episodes of AF. We also found that the effect of oral amiodarone on the duration of the anterograde refractory period of the accessory pathway can (1) be abolished by sympathetic stimulation with isoproterenol and (2) be predicted from the effect of ajmaline or procainamide given intravenously. These observations clearly have practical clinical implications.

Topics: Ajmaline; Amiodarone; Atrial Fibrillation; Benzofurans; Electrophysiology; Heart; Humans; Isoproterenol; Procainamide; Tachycardia, Paroxysmal; Wolff-Parkinson-White Syndrome

Topics: Adolescent; Adult; Aged; Amiodarone; Benzofurans; Eye; Female; Heart Rate; Humans; Hyperthyroidism; Hypothyroidism; Male; Middle Aged; Myocardial Infarction; Tachycardia, Paroxysmal

Topics: Adult; Aged; Amiodarone; Benzofurans; Drug Evaluation; Emergencies; Female; Humans; Infusions, Parenteral; Male; Middle Aged; Tachycardia, Paroxysmal

Topics: Amiodarone; Benzofurans; Electrocardiography; Humans; Male; Middle Aged; Tachycardia; Tachycardia, Paroxysmal

Topics: Adolescent; Adult; Aged; Amiodarone; Benzofurans; Child; Digitalis; Digoxin; Female; Follow-Up Studies; Humans; Male; Medigoxin; Middle Aged; Plants, Medicinal; Plants, Toxic; Tachycardia, Paroxysmal

The Authors tested the effectiveness of amiodarone hydrochloride i.v. in 50 cases of supraventricular hyperkinetic arrhythmias recently aroused. 50 patients, aged 41 to 85 years, with paroxysmal supraventricular tachycardia (PSVT, 21 cases), atrial flutter (7 cases) or fibrillation (22 cases) were treated with 4 mg/Kg of body weight of amiodarone i.v. over 2 min., followed by other 1500 mg/24 hours over 48 hours while amiodarone per os was started for antiarrhythmic prophylaxis; a 12 leads surface ECG and blood pressure were periodically recorded. The sinus rhythm was restored within 3 hours in every case of PSVT (100% of success), within 30 hours in 19 cases of atrial fibrillation (86% of success) and in 5 cases of atrial flutter (71% of success). A slowing down of ventricular frequency ranging from 15 to 40% occurred within 10 min. in case of failure of restoration of sinus rhythm; a slight and transient lengthening of P-R occurred in 1 case; no particular side effects nor noteworthy changes of blood pressure were observed. Amiodarone i.v. proved to be a very effective remedy, handy and well tolerated for the arrhythmias considered above.

Topics: Adult; Aged; Amiodarone; Arrhythmias, Cardiac; Atrial Fibrillation; Atrial Flutter; Benzofurans; Female; Humans; Injections, Intravenous; Male; Middle Aged; Tachycardia, Paroxysmal

In clinical Arrhythmology it is often necessary to associate digitalis and antiarrhythmic agents. This calls for study of possible interaction between the employed drugs. We found a statistically significant correlation between digitalis and amiodarone plasma level in patients on long term treatment with both drugs. A statistically significant linear correlation between plasma amiodarone level and digoxin (0.25 mg/day) or beta-methyldigoxin (0.20 mg/day) was documented in 33 patients. 23 patients had been treated with these drugs for paraxysmal reciprocating supraventricular tachycardia since an average of 52 months (computerized follow-up). (Amiodarone average weekly dose was 1078 +/- 168 mg after a loading dose of 12 gm given over one month). 10 patients were on chronic treatment with higher weekly doses of amiodarone (average dose 2380 +/- 731 mg per week). Thyroid function tests (T4; T3; T3UP; TSH; rT3) were checked in every patients. Further studies are warranted to understand the mechanism of the interaction between amiodarone and digitalis. As a clinical implication we point out that amiodarone-digoxin (or betamethyldigoxin) interaction in our patients has neither resulted in over-therapeutic plasma level nor in signs of digitalis toxicity.

Topics: Aged; Amiodarone; Arrhythmias, Cardiac; Benzofurans; Digoxin; Drug Interactions; Female; Humans; Male; Medigoxin; Middle Aged; Tachycardia, Paroxysmal

Oral amiodarone, an iodine-containing antiarrhythmic agent, was administered to 72 patients with recurrent paroxysmal tachycardias. Thirty-nine patients had tachycardias associated with the Wolff-Parkinson-White syndrome, 15 patients had paroxysmal atrial fibrillation unassociated with the Wolff-Parkinson-White syndrome, and 18 patients had ventricular tachycardia. In all patients, the frequency of symptomatic attacks had not been reduced by at least three other antiarrhythmic agents alone or in combination. The response to amiodarone treatment was graded according to the patients' subjective response (total suppression, partial suppression, and no effect). Overall, 57 per cent of patients had total abolition of attacks and another 22 per cent had a partial suppression of attacks. Side effects, the most common of which were photosensitivity and gastrointestinal upsets, occurred in 44 per cent and were sufficiently severe to warrant withdrawal of treatment in 15 per cent. These results confirm that amiodarone is of considerable value in the treatment of recurrent paroxysmal arrhythmias resistant to other drugs.

Topics: Adolescent; Adult; Aged; Amiodarone; Atrial Fibrillation; Benzofurans; Child; Drug Administration Schedule; Humans; Middle Aged; Tachycardia, Paroxysmal; Wolff-Parkinson-White Syndrome

Topics: Aged; Amiodarone; Benzofurans; Bradycardia; Female; Heart Rate; Humans; Tachycardia, Paroxysmal; Wolff-Parkinson-White Syndrome

Topics: Amiodarone; Benzofurans; Cardiac Pacing, Artificial; Humans; Tachycardia, Paroxysmal

Topics: Adolescent; Adult; Aged; Amiodarone; Atrial Fibrillation; Atrioventricular Node; Benzofurans; Cardiac Pacing, Artificial; Electric Stimulation Therapy; Electrocardiography; Female; Heart Conduction System; Heart Rate; Humans; Male; Middle Aged; Refractory Period, Electrophysiological; Tachycardia, Paroxysmal; Wolff-Parkinson-White Syndrome

Topics: Adult; Amiodarone; Arrhythmias, Cardiac; Benzofurans; Female; Heart Block; Humans; Hypothyroidism; Middle Aged; Tachycardia, Paroxysmal; Thyroid Function Tests

The effects of amiodarone (2.5 mg/Kg i.v.) and of verapamil (0.1 mg/Kg i.v.) on refractory periods and on conduction of structures interested in the reciprocating circuit, as well as on the possible echo zones, were comparatively evaluated through electrophysiological test in 8 patients, four of which with W.P.W. from Kent bundle, and four with double A-V pass with reciprocating supraventricular tachicardia (RST) documented crises. None of the two drugs seems to have the theorical requirements of balanced effect to be chosen for the antiarrhythmic prophylaxis in patients with ventricular pre-excitement. In patients with double A-V pass, while both drugs have a sufficiently balanced and regular action on refractory periods and on conduction the irregularity of their effects on echo zones appears to restrict their validity in chronical therapy. According to the Authors, the only useful criteria for the choice of an antiarrhythmic drug for the prophilaxis of R.S.T. to be derived through extrapolation from these electrophysiological tests are: 1) the functional suppression of a circuit structure; 2) the evaluation of effects on echo zones; 3) the possibility or not the evoking R.S.T.

Topics: Adult; Aged; Amiodarone; Benzofurans; Drug Evaluation; Female; Humans; Male; Middle Aged; Tachycardia, Paroxysmal; Verapamil; Wolff-Parkinson-White Syndrome

The employment of Cordaron (Amidaron) in 50 patients with different arrhythmias proved effective in 86% of the cases. Cordaron was most effective in the treatment and prevention of paroxysmal tachycardia, ventricular extrasystole, paroxysmal cardiac fibrillation. It decreases the pulse rate and moderately decreases the arterial pressure without imparing the patients' state. The drug has practically no toxic effect, is well tolerated, convenient for administration and dosage. Cardiovascular insufficiency is no contraindication for its prescription. Carefulness is needed in prescribing Cordaron to patients with atrioventricular conductivity disorders.

Topics: Aged; Amiodarone; Arrhythmias, Cardiac; Atrial Fibrillation; Benzofurans; Cardiac Complexes, Premature; Drug Evaluation; Female; Hemodynamics; Humans; Male; Middle Aged; Myocardial Contraction; Tachycardia, Paroxysmal

Topics: Amiodarone; Arrhythmias, Cardiac; Benzofurans; Drug Evaluation; Electrocardiography; Female; Humans; Male; Middle Aged; Tachycardia, Paroxysmal

Topics: Amiodarone; Arrhythmias, Cardiac; Benzofurans; Cardiac Complexes, Premature; Drug Evaluation; Humans; Tachycardia, Paroxysmal; Ventricular Fibrillation

Topics: Adolescent; Adult; Aged; Anti-Arrhythmia Agents; Atrial Fibrillation; Atrial Flutter; Benzofurans; Cornea; Female; Heart Conduction System; Humans; Male; Middle Aged; Tachycardia, Paroxysmal; Wolff-Parkinson-White Syndrome

Topics: Angina Pectoris; Antihypertensive Agents; Arrhythmias, Cardiac; Atrial Fibrillation; Atrial Flutter; Benzofurans; Cardiac Complexes, Premature; Humans; Tachycardia; Tachycardia, Paroxysmal