digoxin and Tachycardia--Ventricular

Antiarrhythmic drug therapy, broadly defined, is the mainstay of treatment and prevention of ventricular tachycardia (VT)/ventricular fibrillation (VF), which can lead to sudden death. This article evaluates the evidence for and appropriate use of class I antiarrhythmic drugs, class III antiarrhythmic drugs, beta-blockers, nondihydropyridine calcium-channel blockers, statins, angiotensin enzyme inhibitors, angiotensin receptor blockers, aldosterone blockers, and digoxin for antiarrhythmic benefits in patients who have a propensity for VT/VF and therefore are at risk of sudden death.

Topics: Adrenergic beta-Antagonists; Anti-Arrhythmia Agents; Carbazoles; Carvedilol; Digoxin; Heart Conduction System; Humans; Hydantoins; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Imidazolidines; Piperazines; Propanolamines; Randomized Controlled Trials as Topic; Renin-Angiotensin System; Sotalol; Tachycardia, Ventricular

Digoxin's pharmacological, hemodynamic, and electrophysiological properties are well understood. However, in modern heart failure (HF) treatment, its effect has yet to be fully investigated.. The aim of the present study was to determine the effects of digoxin on outcomes in patients with mild HF implanted with an implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy with defibrillator (CRT-D) device.. We investigated the effect of digoxin treatment on the end points of HF/death, HF alone, death alone, and ventricular tachycardia or ventricular fibrillation (VT/VF) in 1820 patients with mild HF (New York Heart Association class I and II), prolonged QRS duration (≥130 ms), and reduced left ventricular ejection fraction (≤30%) enrolled in the Multicenter Automatic Defibrillator Implantation Trial - Cardiac Resynchronization Therapy trial. Multivariate Cox proportional hazards regression models were used to determine the effect of time-dependent digoxin usage on the end points.. Digoxin therapy was not associated with an increased or decreased risk of HF/death (hazard ratio [HR] 1.07; 95% confidence interval [CI] 0.86-1.33; P = .0.56), HF alone (HR 1.1.04; 95% CI 0.82-1.32; P = .76), or death alone (HR 0.93; 95% CI 0.67-1.32; P = .71). However, digoxin was associated with a significant 41% increased risk of VT/VF (HR 1.41; 95% CI 1.14-1.75; P = .002), which was driven by a significantly increased risk of VT/VF with heart rate ≥200 beats/min (HR 1.65; 95% CI 1.27-2.15; P ≤ .001), whereas no increased risk of VT/VF with heart rate <200 beats/min was evident (HR 1.20; 95% CI 0.92-1.57; P = .19). No significant differences in digoxin's effect on any of the end points were found between patients with ICD and patients with CRT-D (interaction P > .5).. The use of digoxin in patients with mild HF implanted with an ICD or CRT-D device was not associated with reductions in HF/death events. However, digoxin therapy was associated with an increased risk of high-rate VT/VF (≥200 beats/min).

Topics: Canada; Cardiac Resynchronization Therapy; Cardiotonic Agents; Digoxin; Dose-Response Relationship, Drug; Electrocardiography; Europe; Female; Follow-Up Studies; Heart Failure; Heart Rate; Humans; Incidence; Male; Middle Aged; Prognosis; Retrospective Studies; Risk Factors; Survival Rate; Tachycardia, Ventricular; Time Factors; United States

To compare the clinical efficacy of intravenous diltiazem, digoxin, and amiodarone for acute ventricular rate (VR) control in patients with acute symptomatic atrial fibrillation (AF) necessitating hospitalization.. Randomized control trial.. Acute emergency medical admission unit in a regional teaching hospital in Hong Kong.. One hundred fifty adult patients with acute AF and rapid VR (>120 bpm).. Patients were randomly assigned in 1:1:1 ratio to receive intravenous diltiazem, digoxin, or amiodarone for VR control.. The primary end point was sustained VR control (<90 bpm) within 24 hours; the secondary end points included AF symptom improvement and length of hospitalization. At 24 hours, VR control was achieved in 119 of 150 patients (79%). The time to VR control was significantly shorter among patients in the diltiazem group (log-rank test, p < 0.0001) with the percentage of patients who achieved VR control being higher in the diltiazem group (90%) than the digoxin group (74%) and the amiodarone group (74%). The median time to VR control was significantly shorter in the diltiazem group (3 hours, 1-21 hours) compared with the digoxin (6 hours, 3-15 hours, p < 0.001) and amiodarone groups (7 hours, 1-18 hours, p = 0.003). Furthermore, patients in the diltiazem group persistently had the lowest mean VR after the first hour of drug administration compared with the other two groups (p < 0.05). The diltiazem group had the largest reduction in AF symptom frequency score and severity score (p < 0.0001). In addition, length of hospital stay was significantly shorter in the diltiazem group (3.9 +/- 1.6 days) compared with digoxin (4.7 +/- 2.1 days, p = 0.023) and amiodarone groups (4.7 +/- 2.2 days, p = 0.038).. As compared with digoxin and amiodarone, intravenous diltiazem was safe and effective in achieving VR control to improve symptoms and to reduce hospital stay in patients with acute AF.

Topics: Aged; Amiodarone; Anti-Arrhythmia Agents; Atrial Fibrillation; Cohort Studies; Digoxin; Diltiazem; Female; Humans; Infusions, Intravenous; Length of Stay; Male; Middle Aged; Tachycardia, Ventricular; Treatment Outcome

Implantable cardioverter defibrillator (ICD) therapy with backup ventricular pacing increases survival in patients with life-threatening ventricular arrhythmias. Most currently implanted ICD devices provide dual-chamber pacing therapy. The most common comorbid cause for mortality in this population is congestive heart failure.. To determine the efficacy of dual-chamber pacing compared with backup ventricular pacing in patients with standard indications for ICD implantation but without indications for antibradycardia pacing.. The Dual Chamber and VVI Implantable Defibrillator (DAVID) Trial, a single-blind, parallel-group, randomized clinical trial.. A total of 506 patients with indications for ICD therapy were enrolled between October 2000 and September 2002 at 37 US centers. All patients had a left ventricular ejection fraction (LVEF) of 40% or less, no indication for antibradycardia pacemaker therapy, and no persistent atrial arrhythmias.. All patients had an ICD with dual-chamber, rate-responsive pacing capability implanted. Patients were randomly assigned to have the ICDs programmed to ventricular backup pacing at 40/min (VVI-40; n = 256) or dual-chamber rate-responsive pacing at 70/min (DDDR-70; n = 250). Maximal tolerated medical therapy for left ventricular dysfunction, including angiotensin-converting enzyme inhibitors and beta-blockers, was prescribed to all patients.. Composite end point of time to death or first hospitalization for congestive heart failure.. One-year survival free of the composite end point was 83.9% for patients treated with VVI-40 compared with 73.3% for patients treated with DDDR-70 (relative hazard, 1.61; 95% confidence interval [CI], 1.06-2.44). The components of the composite end point, mortality of 6.5% for VVI-40 vs 10.1% for DDDR-70 (relative hazard, 1.61; 95% CI, 0.84-3.09) and hospitalization for congestive heart failure of 13.3% for VVI-40 vs 22.6% for DDDR-70 (relative hazard, 1.54; 95% CI, 0.97-2.46), also trended in favor of VVI-40 programming.. For patients with standard indications for ICD therapy, no indication for cardiac pacing, and an LVEF of 40% or less, dual-chamber pacing offers no clinical advantage over ventricular backup pacing and may be detrimental by increasing the combined end point of death or hospitalization for heart failure.

Topics: Adrenergic beta-Antagonists; Aged; Amiodarone; Angiotensin-Converting Enzyme Inhibitors; Anti-Arrhythmia Agents; Anticoagulants; Arrhythmias, Cardiac; Cardiac Pacing, Artificial; Cardiovascular Agents; Catheter Ablation; Defibrillators, Implantable; Digoxin; Diuretics; Female; Heart Failure; Humans; Male; Middle Aged; Pacemaker, Artificial; Single-Blind Method; Survival Analysis; Tachycardia, Ventricular; Ventricular Dysfunction, Left; Warfarin

Atrial fibrillation (AF) shortens the atrial effective refractory period (ERP) and predisposes to further episodes of AF. The acute changes in atrial refractoriness may be related to tachycardia-induced intracellular calcium overload. The purpose of this study was to determine whether digoxin, which increases intracellular calcium, potentiates the acute effects of AF on atrial refractoriness in humans.. In 38 healthy adults, atrial ERP was measured at basic drive cycle lengths (BDCLs) of 350 and 500 ms after autonomic blockade. Nineteen patients had been treated with digoxin for 2 weeks. After a several-minute episode of AF, atrial ERP was measured serially at alternating BDCLs. Compared with pre-AF ERPs, the first post-AF ERPs were significantly shorter in both the digoxin and the control groups (P:<0.001). The post-AF ERP at a BDCL of 350 ms shortened to a greater degree in the digoxin group (37+/-16 ms) than in the control group (20+/-13 ms, P:<0.001); similar changes occurred at a BDCL of 500 ms. During post-AF determinations of the atrial ERP, secondary AF episodes occurred significantly more often in the digoxin group (32% versus 16%; P:<0. 04).. After a brief episode of AF, digoxin augments the shortening that occurs in atrial refractoriness and predisposes to the reinduction of AF. These effects occur in the setting of autonomic blockade and therefore are more likely to be due to the effects of digoxin on intracellular calcium than to its vagotonic effects.

Topics: Administration, Oral; Adrenergic beta-Antagonists; Adult; Atrial Fibrillation; Calcium; Cardiac Pacing, Artificial; Cardiotonic Agents; Digoxin; Electrocardiography; Female; Heart Atria; Heart Rate; Humans; Infusions, Intravenous; Intracellular Fluid; Male; Parasympatholytics; Reaction Time; Tachycardia, Supraventricular; Tachycardia, Ventricular

We examined clinical outcomes associated with non-randomised digoxin therapy in a postmyocardial infarction population with clinical heart failure (AIRE study). Our results raise concern about the safety of digoxin in this population.

Topics: Adult; Cardiotonic Agents; Digoxin; Female; Follow-Up Studies; Heart Failure; Humans; Male; Middle Aged; Myocardial Infarction; Product Surveillance, Postmarketing; Tachycardia, Ventricular; Treatment Outcome

A population of 283 patients with recent onset (< 72 hours) AF, without heart failure, who received a single 450- or 600-mg oral dose of propafenone, or digoxin 1 mg, or placebo for conversion to sinus rhythm (SR), was studied to determine whether a routine admission to the hospital for drug administration is justified. Previous bradyarrhythmias or sick sinus syndrome (SSS), and concomitant use of antiarrhythmic drugs were exclusion criteria. None of the 283 patients studied experienced VT or VF and none of them needed implantation of a temporary pacemaker. Periods of atrial tachyarrhythmias with regularization of atrial waves and 1:1 AV conduction were observed in only two cases, both receiving placebo. No predictor of proarrhythmia was found among the clinical variables considered (age, etiology, arrhythmia duration, atrial dimension, and blood potassium). No serious hemodynamic adverse effects were noted in either group. The rates of conversion to SR after 4 hours were: 80 (57%) of 141 patients who received propafenone and 35 (25%) of 142 patients who received digoxin or placebo (P < 0.001). Acute oral treatment with propafenone is simple and effective for the conversion of recent onset AF to SR in patients without clinical signs of heart failure. The routine admission of these patients to the hospital is not necessary. Home-based administration of oral propafenone to a selected group of patients could significantly increase the cost effectiveness of this treatment.

Topics: Administration, Oral; Age Factors; Anti-Arrhythmia Agents; Atrial Fibrillation; Atrial Function; Atrioventricular Node; Bradycardia; Cost-Benefit Analysis; Digoxin; Female; Forecasting; Heart Rate; Hemodynamics; Home Care Services; Humans; Male; Middle Aged; Pacemaker, Artificial; Patient Admission; Placebos; Potassium; Propafenone; Retrospective Studies; Sick Sinus Syndrome; Tachycardia; Tachycardia, Ventricular; Ventricular Fibrillation

In this study 24-h Holter electrocardiographic recordings were used to measure the effects of an angiotensin converting enzyme inhibitor, enalapril given for 4 weeks, on the frequency of cardiac arrhythmias in 24 patients (14 patients had enalapril, 30 patients had placebo) with congestive heart failure (New York Heart Association Functional Class 3) receiving maintenance therapy with digoxin and furosemide. Although the placebo group had no change in the frequence of arrhythmias, enalapril-treated patients showed significant decrease in the frequency of premature ventricular complexes couplet, bigemine VPS and ventricular tachycardia. Moreover, it was observed that six cases of atrial fibrillation returned to sinus rhythm. During enalapril treatment, some patients experienced increased serum potassium levels, but there was no change in serum digoxin levels. We also observed echocardiographic improvement in left ventricular function as well as clinical symptoms of congestive heart failure. Finally we observed that there was an antiarrhythmic effect of enalapril in congestive heart failure. We thought that the antiarrhythmic effect of enalapril in congestive heart failure was probably due to hemodynamic improvement.

Topics: Aged; Arrhythmias, Cardiac; Cardiac Complexes, Premature; Digoxin; Double-Blind Method; Electrocardiography, Ambulatory; Enalapril; Female; Heart Failure; Heart Rate; Humans; Male; Middle Aged; Myocardial Contraction; Placebos; Potassium; Tachycardia, Ventricular; Ventricular Function, Left

To establish the value of adjuvant dl-sotalol to digoxin for control of the ventricular response in chronic atrial fibrillation, 60 patients were evaluated in a multicenter, randomized, double-blind, parallel, placebo-controlled study. Patients were evaluated with serial ambulatory ECG monitoring and exercise testing during stable digoxin dosing and then with the addition of either a placebo or dl-sotalol, 80 mg/day, or dl-sotalol, 160 mg/day. The combination of digoxin and dl-sotalol, at either 80 or 160 mg/day, resulted in a statistically significant reduction in heart rate at rest and with exercise during both exercise testing and ambulatory monitoring. No significant difference was observed between the two doses of dl-sotalol. There was no significant difference with regard to symptoms or side effects among the three groups. In summary, dl-sotalol was noted to be a safe and effective adjuvant to digoxin for control of the ventricular response in chronic atrial fibrillation.

Topics: Atrial Fibrillation; Chronic Disease; Digoxin; Double-Blind Method; Drug Therapy, Combination; Electrocardiography, Ambulatory; Female; Humans; Male; Middle Aged; Sotalol; Tachycardia, Ventricular

Topics: Adult; Aged; Aged, 80 and over; Arrhythmias, Cardiac; Atrial Fibrillation; Digoxin; Double-Blind Method; Drug Combinations; Female; Heart Rate; Humans; Magnesium; Male; Middle Aged; Placebos; Prospective Studies; Tachycardia, Ventricular; Time Factors; Ventricular Function

Topics: Aged; Anti-Arrhythmia Agents; Atrial Fibrillation; Digoxin; Electrocardiography; Humans; Potassium; Tachycardia, Ventricular

Topics: Acute Kidney Injury; Aged, 80 and over; Amoxicillin; Anti-Arrhythmia Agents; Anti-Bacterial Agents; Atrial Fibrillation; Bradycardia; Bundle-Branch Block; Clarithromycin; Digoxin; Drug Interactions; Electrocardiography; Female; Helicobacter Infections; Helicobacter pylori; Humans; Hyperkalemia; Immunoglobulin Fab Fragments; Omeprazole; Tachycardia, Ventricular

Topics: Administration, Oral; Aged, 80 and over; Cardiovascular Agents; Coronary Angiography; Diagnosis, Differential; Digoxin; Electrocardiography; Female; Heart Rate; Humans; Predictive Value of Tests; Tachycardia, Ventricular

Topics: Aged; Antibodies; Digitalis; Digoxin; Electrocardiography; Female; Humans; Injections, Intravenous; Tachycardia, Ventricular

In a woman with rheumatic heart disease, atrial flutter with a rapid ventricular response, and congestive heart failure, treatment with digoxin slows conduction in the atrioventricular node and thus allows atrioventricular conduction to occur by way of a previously unrecognized accessory pathway.

Topics: Anti-Arrhythmia Agents; Atrial Flutter; Atrioventricular Node; Digoxin; Electrocardiography; Female; Heart Failure; Humans; Middle Aged; Rheumatic Heart Disease; Tachycardia, Ventricular

"Digitalis toxicity, often candidly indexed as poisoning, has plagued the medical profession for over 200 years. The situation qualifies as a professional disgrace on the basis of three items: the situation persists, physicians are often slow to recognize it and, over the decades, writers have been harsh in their denunciation of fellow physicians when toxicity has occurred…." These are the opening remarks of an essay published in 1983 on the 2nd centenary of William Withering's 'magic potion from foxglove's extract for dropsy.' Even today, after many decades, these words appear relevant! We present and discuss an interesting ECG of digitalis toxicity.

Topics: Adult; Cardiomyopathy, Dilated; Cardiotonic Agents; Digoxin; Electrocardiography; Female; Heart Conduction System; Humans; Tachycardia, Ventricular

Topics: Aged; Atorvastatin; Cardiovascular Agents; Digoxin; Drug Therapy, Combination; Female; Furosemide; Heptanoic Acids; Humans; Isosorbide Dinitrate; Lisinopril; Nitroglycerin; Pyrroles; Recurrence; Tachycardia, Ventricular; Warfarin

Recent investigations have demonstrated that the occurrence of implantable cardioverter-defibrillator (ICD) shocks is associated with adverse long-term outcomes. These studies have emphasized that the risk is most reasonably due to arrhythmias rather than to the shock itself. We sought to compare the impact of shock delivery for induced ventricular arrhythmias during implantation defibrillation threshold testing and noninvasive electrophysiology study (NIPS) to clinical shocks on long-term outcomes among patients with ICDs.. This was a cohort evaluation of 1,372 patients undergoing ICD implantation at a tertiary hospital from December 1997 to January 2007. The probability of all-cause mortality and hospitalization for acute decompensated heart failure (ADHF) was evaluated based upon the type of ICD shock received using multivariable Cox proportional analyses. The four shock types analyzed were implantation shocks only (n = 694), additional NIPS shocks only (n = 319), additional appropriate shocks only (n = 128), or additional inappropriate shocks only (n = 104).. The risk of death (adjusted hazard ratio [AHR] 0.91 [95% confidence interval (CI) 0.69-1.20]; P = .491) or ADHF (AHR 0.71 [95% CI 0.46-1.16]; P = .277) were similar between recipients of NIPS shocks and recipients of implantation shocks. Receiving an appropriate ICD shock increased the risk of death (AHR 2.09 [95% CI 1.38-2.69]; P <.001) and ADHF (AHR 2.40 [95% CI 1.51-3.81]; P <.002) as compared with implantation shocks and also increased the risk of death (AHR 2.61 [95% CI 1.86-3.67]; P <.001) and ADHF (AHR 2.29 [95% CI 1.33-3.97]; P = .003) as compared with NIPS shocks.. ICD shocks delivered during induced ventricular arrhythmias at the time of NIPS testing does not increase the risk of death or ADHF as compared with recipients of appropriate ICD shocks. The occurrence of spontaneous arrhythmias in vulnerable substrates may explain the increased risk.

Topics: Aged; Anti-Arrhythmia Agents; Cohort Studies; Confidence Intervals; Connecticut; Defibrillators, Implantable; Digoxin; Electrophysiology; Female; Heart Failure; Humans; Kaplan-Meier Estimate; Male; Multivariate Analysis; Phenethylamines; Prognosis; Proportional Hazards Models; Retrospective Studies; Risk Factors; Sulfonamides; Tachycardia, Ventricular; Treatment Outcome; Ventricular Fibrillation

Of 209 patients with heart failure treated with combined cardiac resynchronization therapy and implantable cardioverter-defibrillator therapy, appropriate cardioverter-defibrillator shocks occurred at 34-month follow-up in 22 of 121 patients (18%) on statins and in 30 of 88 patients (34%) not on statins (P = .009). Deaths occurred in 3 of 121 patients (2%) on statins and in 9 of 88 patients (10%) not on statins (P = .017). Stepwise Cox regression analysis showed that significant independent prognostic factors for appropriate shocks were use of statins (risk ratio = 0.46), smoking (risk ratio = 3.5), and diabetes (risk ratio = 0.34). Significant independent prognostic factors for the time to mortality were use of statins (risk ratio = 0.05), use of digoxin (risk ratio = 4.2), systemic hypertension (risk ratio = 14.2), diabetes (risk ratio = 4.3), and left ventricular ejection fraction (risk ratio = 1.1).

Topics: Aged; Aged, 80 and over; Cardiac Pacing, Artificial; Cardiotonic Agents; Combined Modality Therapy; Defibrillators, Implantable; Diabetes Complications; Digoxin; Female; Heart Failure; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypertension; Male; Middle Aged; Odds Ratio; Proportional Hazards Models; Risk Assessment; Risk Factors; Smoking; Stroke Volume; Tachycardia, Ventricular; Time Factors; Treatment Outcome; Ventricular Fibrillation; Ventricular Function, Left

Topics: Aged; Atrial Fibrillation; Chronic Disease; Contraindications; Coronary Artery Bypass; Digoxin; Drug Interactions; Electrocardiography; Humans; Hypertension; Male; Postoperative Complications; Quinine; Syncope; Tachycardia, Ventricular; Torsades de Pointes; United Kingdom

Topics: Acute Kidney Injury; Aged; Atrial Fibrillation; Bundle-Branch Block; Digitalis; Digoxin; Electrocardiography; Humans; Male; Metoprolol; Tachycardia, Ventricular

The right ventricular outflow tract (RVOT) has been demonstrated as an important focus in idiopathic ventricular arrhythmias. However, the role of the gap junction in this region in arrhythmic events has not been fully investigated. The purpose of this study was to evaluate the expression and distribution of the gap junction protein connexin 43 (Cx43) in the myocardium of the RVOT area of normal adult rabbits. Tissue samples were obtained from 6 regions of normal rabbit heart, i.e. the left ventricle (LV) free wall, the LV papillary muscle, the RVOT free wall, and the RVOT septum which was subdivided into the RV side, the central layer, and the LV side. Immunohistochemical analysis was performed to investigate the characteristics of Cx43 distribution in the RVOT area. In the LV free wall and papillary muscle, Cx43 was abundantly, homogeneously, and approximately equally expressed in end-to-end- and side-to-side intercellular connections. In the free wall of the RVOT, Cx43 expression was poor compared to both these LV regions and side-to-side cell connections were predominant. Cx43 was as richly and homogeneously distributed in the central layer and LV side of the RVOT septum as in the two LV regions. However, in the RV side of the RVOT septum, its distribution was scant and an unstained area was noted. The heterogeneous expression of Cx43 in the RVOT area may serve as substrate for idiopathic ventricular arrhythmia.

Topics: Animals; Connexin 43; Digoxin; Electrocardiography; Female; Gap Junctions; Heart Ventricles; Male; Myocardium; Rabbits; Tachycardia, Ventricular; Ventricular Function; Ventricular Function, Right

Topics: Aged; Aged, 80 and over; Anti-Arrhythmia Agents; Atrial Fibrillation; Chronic Disease; Digoxin; Electrocardiography; Female; Humans; Tachycardia, Ventricular

Topics: Administration, Oral; Aged; Anti-Arrhythmia Agents; Atrial Fibrillation; Digoxin; Electrocardiography; Female; Humans; Tachycardia, Ventricular; Time Factors

Topics: Aged; Amiodarone; Anti-Arrhythmia Agents; Atrial Fibrillation; Digoxin; Drug Synergism; Drug Therapy, Combination; Electrocardiography; Emergency Treatment; Heart Failure; Humans; Male; Tachycardia, Ventricular

The efficacy and safety of amiodarone in the management of atrial fibrillation (AF) or flutter in 108 Japanese patients with heart failure was retrospectively examined. Thirty-four (41%) of the 82 patients who were in sinus rhythm after 1 month of amiodarone administration had their first recurrence, 70% of cases occurring within 1 year of initiation. The cumulative rates of maintenance of sinus rhythm were 0.68, 0.55, and 0.47 at 1, 3, and 5 years, respectively. Amiodarone was more effective in maintaining sinus rhythm in patients with paroxysmal AF or flutter than in those with the persistent form (p<0.05). The cumulative rates for cases that remained in permanent AF were 0.04, 0.11, and 0.14 at 1, 3, and 5 years, respectively. Apart from suppressing AF, the mean heart rate during Holter monitoring was significantly decreased with amiodarone therapy in cases of permanent AF. Adverse effects requiring the discontinuation of amiodarone therapy occurred in 16% of patients. Low-dose amiodarone therapy may prevent AF or flutter in Japanese patients with heart failure.

Topics: Amiodarone; Angiotensin-Converting Enzyme Inhibitors; Anti-Arrhythmia Agents; Atrial Fibrillation; Atrial Flutter; Cause of Death; Digoxin; Dose-Response Relationship, Drug; Female; Follow-Up Studies; Heart Diseases; Heart Failure; Humans; Male; Middle Aged; Recurrence; Retrospective Studies; Survival Analysis; Tachycardia, Ventricular; Time Factors; Treatment Outcome

Atrioventricular (AV) dissociation is an electrocardiographic syndrome; a descriptive term for a variety of conditions of abnormal cardiac conduction which all feature independent function of the atria and ventricles. AV dissociation can be subclassified as AV dissociation by default (an independent ventricular pacemaker responds to slowing of the dominant atrial pacemaker) versus AV dissociation by usurpation (acceleration of a latent pacemaker takes control of cardiac conduction by exceeding the intrinsic atrial rate). Inclusion of third degree AV block (complete heart block) as a manifestation of AV dissociation is controversial, yet is functionally appealing in that this disorder also features independent activity of the atria and ventricles.

Topics: Aged; Arrhythmias, Cardiac; Bradycardia; Calcium Channel Blockers; Coronary Disease; Diagnosis, Differential; Digoxin; Electrocardiography; Emergencies; Female; Heart Atria; Heart Block; Heart Ventricles; Humans; Male; Middle Aged; Sinoatrial Node; Suicide; Tachycardia, Ventricular

In the present study, the possible role of oxygen-derived free radicals (OFR) on digoxin- (0.6 mg/kg(-1) IV bolus) induced arrhythmias of anesthetized guinea-pigs has been investigated. Guinea-pigs (300400 g) of either sex were anesthetized with urethane (1.5 g/kg(-1),IP), and their trachea for respiration, left common carotid artery for blood pressure monitoring, and right jugular vein for drug administration were cannulated. ECG and haemodynamics were recorded throughout the experiments. None of the agents used [N-acetyl-L-cysteine (20 mg/kg(-1)IV bolus), or SOD (30,000 IU/kg(-1) IV bolus) + catalase (15,000 IU/kg(-1) IV bolus)] significantly inhibited the arrhythmias except desferrioxamine which reduced the incidence of ventricular fibrillation and arrhythmia score. Desferrioxamine, by acting intracellularly unlike other agents used, might prevent the reduction of Fe(+3) by ascorbate and superoxide anion thus inhibiting the formation of cytotoxic hydroxyl radical in this experimental setting.

Topics: Animals; Antioxidants; Arrhythmias, Cardiac; Digoxin; Electrocardiography; Female; Free Radical Scavengers; Free Radicals; Guinea Pigs; Male; Reactive Oxygen Species; Tachycardia, Ventricular; Ventricular Fibrillation

Topics: Aged; Cardiotonic Agents; Diagnosis, Differential; Digoxin; Electrocardiography; Female; Humans; Hypokalemia; Syncope; Tachycardia, Ventricular; Ventricular Premature Complexes

Topics: Aged; Atrial Fibrillation; Digoxin; Electrocardiography; Female; Humans; Tachycardia, Ventricular

The main aim of the study was to test the hypotheses that (a) concentrations of endogenous digoxin-like factor (EDLF) are increased in the initial period after acute myocardial infarction (AMI) and (b) may contribute to the onset of ventricular arrhythmias. 54 patients of both sexes with a first transmural AMI were included in a retrospective study. Plasma concentrations of EDLF were measured repeatedly during days 1-14 after AMI using DELFIA digoxin fluoroimmunoassay. 16 male patients with unstable angina pectoris and suspected AMI as well as 8 healthy subjects of both sexes served as controls. Plasma concentrations of EDLF in patients during the first day of AMI were increased (1.25 + (-)0.26 ng/ml, digoxin equivalents, p < 0.05) as compared with both healthy controls (0.34 + (-)0.08 ng/ml) and patients with unstable angina pectoris (0.4 + (-)0.06 ng/ml). First day after AMI plasma levels of EDLF in 7 patients with primary ventricular fibrillation were higher (2.54 + (-)0.67 ng/ml, p < 0.03) than in 47 patients without ventricular fibrillation (1.05 + (-)0.27 ng/ml). In 14 patients with AMI and congestive heart failure (class III, Killip) plasma concentrations of EDLF were significantly lower (0.32 + (-)0.09 ng/ml, p < 0.03) than in 40 patients with AMI without congestive heart failure (1.51 + (-)0.32 ng/ml). Starting from the second day of AMI plasma EDLF decreased to the level of control and did not change during two weeks of observation. These results, being in agreement with our previous experimental data, show an increase of plasma EDLF after AMI and suggest that EDLF may be involved in myocardial ischemia-induced arrhythmogenesis and participate in pathogenesis of congestive heart failure after AMI.

Topics: Adult; Aged; Angina, Unstable; Biomarkers; Cardenolides; Digoxin; Enzyme Inhibitors; Female; Fluoroimmunoassay; Heart Failure; Humans; Male; Middle Aged; Myocardial Infarction; Prognosis; Retrospective Studies; Saponins; Sodium-Potassium-Exchanging ATPase; Tachycardia, Ventricular

Although digoxin antibodies are the definitive treatment of cardiac arrhythmias due to digoxin toxicity, magnesium can also be effective especially with low serum magnesium levels. The case report describes a patient with digoxin toxicity, ventricular tachycardia and a slightly elevated serum magnesium. Two 10 mmol doses of intravenous magnesium sulfate were associated with a more stable junctional rhythm with bigeminy. Magnesium is known to suppress early after depolarizations, and in supraphysiological doses, may act as an indirect antagonist of digoxin at the sarcolemma Na(+)-K(+)-ATPase pump. Intravenous magnesium may be used to treat cardiac arrhythmias due to digoxin poisoning where there is likely to be a delay in the availability of digoxin antibodies, even in the presence of elevated serum magnesium.

Topics: Aged; Aged, 80 and over; Digoxin; Electrocardiography; Female; Humans; Injections, Intravenous; Magnesium Sulfate; Tachycardia, Ventricular

A 55 year-old female ingested two bulbs of Urginea maritime (squill) plant as a folk remedy for her arthritic pains. Her past history was significant for Hashimoto thyroiditis and she was hypothyroid upon presentation. Subsequent effects resembling those seen with cardiac glycoside intoxication included nausea, vomiting, seizures, hyperkalemia, atrioventricular block and ventricular arrhythmias resembling digitalis toxicity. A serum digoxin level by an enzyme immunoassay method was 1.59 ng/mL. Despite supportive treatment and pacing, the patient expired from ventricular arrhythmias 30 h after ingestion. Squill has been recognized since antiquity for the clinical toxicity of its cardiac glycosides, but this appears to be the first report of a fatality since 1966.

Topics: Digoxin; Electrocardiography; Fatal Outcome; Female; Fluorescence Polarization Immunoassay; Gastric Lavage; Humans; Medicine, Traditional; Middle Aged; Plant Poisoning; Plants, Medicinal; Tachycardia, Ventricular; Turkey

To analyze if patient selection bias could contribute to the improved prognosis reported for ventricular tachycardia (VT) and ventricular fibrillation (VF) when therapy is guided by electrophysiologic studies (EPS), we studied 90 consecutive patients admitted to a tertiary referral center with recent VT/VF who were candidates for EPS. Seventeen patients (19%) died during the initial hospital admission, and 30 (33%) died after discharge. Survival probability was 0.83 (95% confidence interval [CI], 0.74-0.90); 0.67 (95% CI, 0.56-0.75); and 0.53 (95% CI, 0.42-0.63) at 1 month, 1 year, and 3 years, respectively. Of the 56 patients (62%) who underwent EPS during their initial hospitalization, only 1 died during that admission. Patients in whom EPS could not be performed had characteristics associated with a poorer prognosis. NYHA functional class (p = 0.005), inability to perform baseline EPS (p = 0.003) and use of digoxin (p = 0.016) were independent predictors of death. Early in-hospital mortality in patients with VT/VF remains high. Thus, omission of these deaths in reports of EPS-guided therapy creates incomplete, biased cohorts. Furthermore, there may be a bias toward a healthier population among hospital survivors undergoing EPS. These findings may contribute to better outcomes in current series compared to historical controls.

Topics: Aged; Analysis of Variance; Anti-Arrhythmia Agents; Cardiac Care Facilities; Cause of Death; Cohort Studies; Defibrillators, Implantable; Digoxin; Electrophysiology; Female; Follow-Up Studies; Humans; Male; Middle Aged; Multivariate Analysis; Prognosis; Retrospective Studies; Selection Bias; Survival Analysis; Tachycardia, Ventricular; Ventricular Fibrillation

Digitalis intoxication is one of the most common adverse drug reactions. Although some arrhythmias are seen more frequently than others, virtually any rhythm disturbance, including ventricular tachycardia, may occur. However, to our knowledge, exercise-induced ventricular tachycardia as a complication of digitalis therapy has never been described before. This case presents a patient with a digitalis-induced ventricular tachycardia occurring exclusively during exercise.

Topics: Digoxin; Electrocardiography; Exercise Test; Female; Humans; Middle Aged; Tachycardia, Ventricular

Atrial fibrillation is the commonest arrhythmia observed in hypertrophic cardiomyopathy, and is associated with an acute deterioration in symptoms. Digoxin is the drug of choice in established atrial fibrillation and amiodarone the drug of choice in paroxysmal atrial fibrillation and ventricular arrhythmia. Non-sustained ventricular tachycardia occurs in 20% of patients and is the single best predictor of sudden death in adults. Sustained monomorphic ventricular tachycardia occurs only rarely. The mechanism of sudden death is likely to involve initiating factors such as arrhythmia and peripheral autonomic dysfunction causing haemodynamic instability and myocardial ischaemia. Myocardial disarray may provide the arrhythmogenic substrate such that haemodynamic instability and ischaemia results in ventricular fibrillation and sudden death.

Topics: Amiodarone; Atrial Fibrillation; Cardiomyopathy, Hypertrophic; Death, Sudden, Cardiac; Digoxin; Electrocardiography; Humans; Tachycardia, Ventricular

Topics: Adams-Stokes Syndrome; Cervix Uteri; Diagnosis, Differential; Digoxin; Electrocardiography; Female; Heart Block; Humans; Menstruation Disturbances; Phenobarbital; Succinylcholine; Surgical Procedures, Operative; Tachycardia; Tachycardia, Ventricular

Topics: Anti-Arrhythmia Agents; Atropine; Blood Pressure; Blood Pressure Determination; Digoxin; Dogs; Epinephrine; Hydrocarbons; Methoxamine; Ouabain; Pharmacology; Quinidine; Research; Tachycardia; Tachycardia, Ventricular

Topics: Atrial Fibrillation; Diagnosis, Differential; Digoxin; Electrocardiography; Humans; Procainamide; Prognosis; Quinidine; Tachycardia; Tachycardia, Ventricular; Wolff-Parkinson-White Syndrome