A decade of clinical trial developments in postmyocardial infarction, congestive heart failure, and sustained ventricular tachyarrhythmia patients: from CAST to AVID and beyond. Cardiac Arrhythmic Suppression Trial. Antiarrhythmic Versus Implantable Defibrillators

Ventricular Arrhythmias in Patients with Implanted Cardiac Devices at High Risk of Obstructive Sleep Apnea

Background and Objectives: Patients with pre-existing cardiac disease have a higher prevalence of Obstructive Sleep Apnea (OSA). OSA has been associated with an increased risk of supraventricular and ventricular arrhythmia. We screened subjects with implanted pacemakers and automated implantable cardioverter defibrillators (AICD) for OSA with the Berlin Questionnaire and compared the incidence of ventricular arrhythmias and automated implantable cardioverter defibrillator (AICD) firing between high and low OSA risk groups. Materials and Methods: We contacted 648 consecutive patients from our arrhythmia clinic to participate in the study and performed final analyses on 171 subjects who consented and had follow-up data. Data were abstracted from the electronic health record for the incidence of non-sustained ventricular tachycardia (NSVT), ventricular tachycardia (VT), ventricular fibrillation (VF) and AICD firing and then compared between those at high versus low risk of OSA using the Berlin Questionnaire and multivariate negative binomial regression. Results: The average follow-up period was 24.2 ± 4.4 months. After adjusting for age, gender and history of heart failure, those subjects at high risk of OSA had a higher burden of NSVT vs. those with a low risk of OSA (33.4 ± 96.2 vs. 5.82 ± 17.1 episodes, p = 0.003). A predetermined subgroup analysis of AICD recipients also demonstrated a significantly higher burden of NSVT in the high vs. low OSA risk groups (66.2 ± 128.6 vs. 18.9 ± 36.7 episodes, p = 0.033). There were significant differences in the rates of VT, VF or AICD shock burden between the high and low OSA risk groups and in the AICD subgroup analysis. Conclusions: There was increased ventricular ectopy among pacemaker and AICD recipients at high risk of OSA, but the prevalence of VT, VF or AICD shocks was similar to those with low risk of OSA.

Amiodarone: what have we learned from clinical trials?

Amiodarone is an antiarrhythmic agent commonly used in the treatment of supraventricular and ventricular tachyarrhythmias. This paper reviews clinical trials in which amiodarone was used in one of the treatment arms. Key post-myocardial infarction trials include EMIAT and CAMIAT, both of which demonstrated that amiodarone reduced arrhythmic but not overall mortality. In patients with congestive heart failure (CHF), amiodarone was associated with a neutral survival in CHF/STAT and improvement in survival in GESICA. In patients with nonsustained ventricular tachycardia, the MADIT trial demonstrated that therapy with an implantable cardioverter-defibrillator (ICD) improved survival compared with the antiarrhythmic drug arm in such patients, most of whom were taking amiodarone. In sustained VT/VF patients, the CASCADE trial demonstrated that empiric amiodarone lowered arrhythmic recurrence rates compared with other drugs guided by serial Holter or electrophysiologic studies. Several trials including AVID, CIDS, and CASH have demonstrated the superiority of ICD therapy compared with empiric amiodarone in improving overall survival. Clinical implications of these trials are discussed.

A review of clinical trials assessing the efficacy and safety of newer antiarrhythmic drugs in atrial fibrillation

Clinical trials assessing the efficacy of anti- arrhythmic drugs for terminating atrial fibrillation have demonstrated that rate control drugs have little to no added efficacy compared to placebo; however, spontaneous conversion of recent-onset atrial fibrillation is common. Antiarrhythmic drugs such as oral dofetilide, oral bolus-flecainide and propafenone and intravenous ibutilide all have a role in terminating atrial fibrillation. Active comparator trials have demonstrated that amiodarone is more efficacious in maintaining sinus rhythm than propafenone and sotalol. Multiple trials have demonstrated the safety of amiodarone, sotalol, dofetilide and azimilide in a post-myocardial infarction population and amiodarone and dofetilide in a congestive heart failure population. Newer antiarrhythmic agents, some with novel mechanisms of action, will add to the pharmacologic armamentarium in treating atrial fibrillation.

Atrial Fibrillation in Heart Failure:

AF in Heart Failure. Atrial fibrillation and congestive heart failure are commonly occurring cardiac disorders that often exist concomitantly. The prognostic significance of the presence or absence of atrial fibrillation, as an independent risk factor, in patients with heart failure remains controversial. Antiarrhythmic drugs with good hemodynamic profiles and neutral effects on survival are preferred treatments for converting atrial fibrillation and maintaining sinus rhythm. Other standard therapies for congestive heart failure, such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and beta-blockers also have a role in the treatment of these coexisting disease states. The article presents an overview of atrial fibrillation in patients with heart failure and reviews the prevalence, prognostic significance, and efficacy of various antiarrhythmic agents for the conversion and maintenance of sinus rhythm.

ICD Therapy for the Prevention of Sudden Cardiac Death in Post-MI Patients

Implantable cardioverter-defibrillators (ICDs) are unequivocally the treatment of choice for patients who have already experienced a near-fatal tachyarrhythmic event. Recently, studies have conclusively demonstrated that extending the benefits of ICD therapy to postinfarction patients with resultant left ventricular dysfunction results in dramatic additional lifesaving without the need for complex risk- stratification procedures. The landmark Multicenter Automatic Defibrillator Implantation Trial II (MADIT II) shows that patients with reduced left ventricular function (ejection fraction < 30%) 1 month after a myocardial infarction should receive an ICD to prevent sudden cardiac death.

Old and new antiarrhythmic drugs for converting and maintaining sinus rhythm in atrial fibrillation: comparative efficacy and results of trials

In managing atrial fibrillation (AF), the main therapeutic strategies include rate control, termination of the arrhythmia, and the prevention of recurrences and thromboembolic events. Safety and efficacy considerations are important in optimizing the choice of an antiarrhythmic drug for the treatment of AF. Recently approved antiarrhythmics, such as dofetilide, and promising investigational drugs, such as azimilide and dronedarone, may change the treatment landscape for AF. For medical conversion of recent-onset AF, class IC antiarrhythmic drugs, administered as an oral bolus, have been demonstrated to be the most efficacious pharmacologic conversion agents. Intravenous ibutilide and oral dofetilide both have efficacies superior to placebo in controlled trials for converting persistent AF. Comparative trials in paroxysmal AF have demonstrated that flecainide, propafenone, quinidine, and sotalol are equally effective in preventing recurrences of AF. Amiodarone has been demonstrated to be more efficacious than propafenone or sotalol in the Canadian Trial of Atrial Fibrillation. In persistent AF, twice-daily dofetilide has been shown to be as or more effective than low-dose sotalol given twice daily for the maintenance of sinus rhythm in patients with AF. Trials have demonstrated that subjective adverse effects are less frequent with class IC drugs, sotalol, and dofetilide compared with such drugs as quinidine. In patients without structural heart disease, flecainide, propafenone, and D,L-sotalol are the initial drugs of choice, given their reasonable efficacy, low incidence of subjective side effects, and lack of significant end-organ toxicity. Treating AF in patients with left ventricular dysfunction can be difficult because of associated electrophysiologic derangements, potential proarrhythmic concerns, and negative inotropic effects of antiarrhythmics. Some data exist suggesting that angiotensin-converting enzyme inhibitors and angiotensin receptor blockers can prevent AF either by preventing atrial dilation and stretch-induced arrhythmias or by blocking the renin-angiotensin system. In post-myocardial infarction patients, D,L-sotalol, dofetilide, and amiodarone-and in congestive heart failure patients, amiodarone and dofetilide-have demonstrated neutral effects on survival in controlled trials. In the Congestive Heart Failure Survival Trial of Antiarrhythmic Therapy (CHF-STAT), amiodarone lowered the frequency of AF development and improved left ventricular ejection fraction over time. In CHF-STAT, there was lower mortality in patients who converted from AF to sinus rhythm. Dofetilide decreased rehospitalization for congestive heart failure in the Danish Investigations of Arrhythmia and Mortality on Dofetilide (DIAMOND) trials. Neutral effects on survival and favorable hemodynamics have positioned amiodarone and dofetilide as the antiarrhythmics of choice in patients with left ventricular dysfunction. In post-myocardial infarction patients, sotalol is an additional agent to consider for treatment of AF in this setting.

Arrhythmias in Patients with Heart Failure

Both atrial and ventricular arrhythmias are very common in patients with congestive heart failure, and their presence is associated with symptoms, significant morbidity, and mortality. Studies have attempted to determine the prognostic significance of atrial and ventricular arrhythmias in patients with heart failure. Whether atrial fibrillation is an independent risk factor of mortality remains controversial. The presence of ventricular arrhythmias in patients with ischemic cardiomyopathy identifies patients at high risk for sudden death. However, in patients with nonischemic cardiomyopathy there is not a strong correlation between ventricular arrhythmias and increased risk for sudden death. Multiple trials using antiarrhythmic drugs, pharmacologic therapy, and implantable cardioverter defibrillators have been performed in an attempt to improve survival in patients 1) post-myocardial infarction; 2) with congestive heart failure, with and without nonsustained ventricular tachycardia; and 3) with sustained ventricular tachycardia and those who have survived an out-of-hospital cardiac arrest. The purpose of this article is to present an overview of arrhythmias in patients with heart failure and discuss the prevalence, prognostic significance, complications, mechanisms, and trials that have formed the current therapies presently used.

Maintaining stability of sinus rhythm in atrial fibrillation: antiarrhythmic drugs versus ablation

In managing atrial fibrillation, the main therapeutic strategies include rate control, termination of the arrhythmia, and pr vention of recurrences and thromboembolic events. Rate control with digoxin, b-blockers, verapamil, and diltiazem may be preferred in drug refractory and sedentary patients with markedly dilated left atrium and atrial fibrillation of long duration. Drugs useful in the maintenance of sinus rhythm include quinidine, procainamide, disopyramide, sotalol, amiodarone, dofetilide, flecainide, and propafenone. In patients with structural heart disease, the class III antiarrhythmics are the initial drugs of choice, given their neutral effects on survival in a post-myocardial infarction and congestive heart failure population. Due to high recurrence rates with pharmacologic therapy, nonpharmacologic options of therapy include atrioventricular junction ablation, atrial defibrillators, catheter ablation of pulmonary vein foci, and attempts to perform an atrial Maze procedure using catheters. Hybrid therapy using drugs in combination with nonpharmacologic approaches will be used more frequently in the future for refractory patients.

Do ACE inhibitors or angiotensin II antagonists reduce total mortality and arrhythmic mortality? A critical review of controlled clinical trials

ACE-inhibitors (ACE-I) represent effective drugs more and more widely used in acute myocardial infarction (AMI) patients, in post AMI patients and mainly, today, in CHF patients.A complete review of the scientific literature and of all the randomized controlled clinical trials (RCTs), where ACE-I have been tested directly or in association with other drugs, have been performed. ACE-I effects on total mortality (TM) and arrhythmic mortality (AM) and other composite clinical endpoints have been evaluated. It is well known that frequent ventricular arrhythmias (VA) and a high incidence of sudden death (SD) can be documented in CHF patients; nevertheless a direct relationship between VA, TM, and AM has not been clearly demonstrated; neither beneficial effects, on the same endpoints, of the treatment and suppression of ambient VA in CHF. Conversely, sometimes clear negative effects on both TM and AM have been observed. According to individual studies and two recent complete and large metanalysis, ACE-I were unable to reduce AM, but they reduced TM. Furthermore, they can affect and modify many, if not all, of the triggering factors of VA and SD in this context. Differently from ACE-I, betablockers (BB) have been clearly associated with a reduction in TM and AM, in the same context. Thus, at present time, ACE-I, with or without BB, should be considered the standard therapy in all patients with CHF, if not contraindicated. Angiotensin II antagonists (AII-a) probably represent a comparably effective treatment, in all CHF patients and mainly in those patients, suffering from side effects or showing intolerance to ACE-I, but we are still lacking definitive data from RCTs. In many RCTs, conducted with traditional antiarrhythmic drug therapy (ADT), these drugs have been widely used, contributing probably, in a consistent way, to some of the positive results of these studies. All primary and some secondary implantable defibrillators (ICD) RCTs, in the prevention of SD, have included these drugs as the standard treatment of the underlying cardiac disease, with or without CHF. The same therapeutical strategy is regularly applied in all biventricular pacing (BP) RCTs, with or without the ICD. These trials are supposed to assess the reduction in TM and AM, preventing deterioration or progression of CHF and improving the quality of the patients' s life.Finally, according to these clinical evidences, in the last part of the review, we stress the need for a more widespread implementation of ACE-I and AII-a in treating CHF patients.

Role of Antiarrhythmic Therapy in Patients at Risk for Sudden Cardiac Death: An Evidence-Based Review

Sudden cardiac death (SCD) accounts for more than half of all cardiac deaths occurring each year in the United States. Although it has several causes, patients at greatest risk are those with coronary artery disease and impaired left ventricular function, heart failure secondary to ischemia or idiopathic dilated cardiomyopathy, hypertrophic cardiomyopathy, documented sustained ventricular tachycardia or ventricular fibrillation, and survivors of cardiac arrest. The presence of asymptomatic ventricular arrhythmias, positive signal-averaged electrocardiogram (ECG), low heart rate variability index, or inducible ventricular tachycardia or ventricular fibrillation increases the risk. In primary prevention trials in patients with ischemic heart disease, beta-blockers reduced both total mortality and SCD, whereas class I antiarrhythmic drugs, especially class IC, increased mortality. Among class III agents, d,l-sotalol and dofetilide have a neutral effect on mortality, whereas d-sotalol increases mortality. Amiodarone has a neutral effect on total and cardiac mortality but does reduce the risk of arrhythmic death and cardiac arrest. Three primary prevention trials in patients with ischemic heart disease were conducted with implantable cardioverter-defibrillators (ICDs). Patients with low ejection fractions (EFs), asymptomatic ventricular arrhythmias, and inducible ventricular tachycardia or ventricular fibrillation had significant reductions in total, cardiac, and arrhythmic death with ICDs compared with either no drug therapy or conventional antiarrhythmic agents. The ICDs did not reduce mortality in patients with low EFs and a positive signal-averaged ECG undergoing coronary bypass graft. In those with heart failure, beta-blockers reduced total and SCD mortality, but dofetilide and amiodarone had a neutral effect on mortality. In the secondary prevention of SCD, antiarrhythmic drugs alone generally are not thought to improve survival. In three trials in patients with documented sustained ventricular tachycardia or ventricular fibrillation, or survivors of SCD, ICDs reduced cardiac and arrhythmic mortality. Total mortality, however, was significantly reduced in only one of these trials. The role of antiarrhythmic drugs in secondary prevention of SCD is limited to patients in whom ICD is inappropriate or in combination with ICD. Antiarrhythmics can be given selectively with ICDs to decrease episodes of ventricular tachycardia or fibrillation to reduce ICD discharges, to suppress episodes of nonsustained ventricular tachycardia that trigger ICD discharges, to slow the rate of ventricular tachycardia to increase hemodynamic stability, to allow effective antitachycardia pacing, or to suppress supraventricular arrhythmias.

A semi-automatic algorithm for reducing the time spent on routine follow-up of cardioverter defibrillators

Background

The routine follow-up of cardioverter defibrillators (CD) is a time-consuming procedure.

Aim of the Study and Methods

The present study was a prospective randomized cross-over evaluation on the clinical usefulness of a specific semi-automatic software algorithm (Quick Check) for CD follow-up, available in CPI Guidant systems (CD and programmer). Time-saving, while ensuring all the required data and patient safety, was evaluated in a large group of patients (105), recruited in different centers. In the same session and under a physician's supervision all patients underwent a follow-up with the aid of Quick Check or a standard follow-up, in a randomized sequence. Each patient served as his own control.

Results

In the overall population of 105 patients, the time spent for follow-up was reduced by Quick Check from 186±105 sec to 106±67 sec (p<0.0001) (43% reduction). The reduction in time spent for follow-up with Quick Check was the same (43% reduction) in patients with detected episodes (n=38) (from 241±144 sec to 138±95 sec (p<0.0001)) and in patients without detected episodes (n=67) (from 154±52 sec to 88±34 sec (p<0.0001)). No adverse events or deletion of potentially useful data was detected by the supervising physician.

Conclusions

Use of a specific software algorithm for routine follow-up of implanted CDs allows a significant shortening of the time spent on routine follow-up, thus reducing costs. The supervision of a physician is a guarantee of patient safety.

Implantable Cardioverter Defibrillator: Current Progress and Management

With greater technologic advances during the past decade, use of the implantable cardioverter defibrillator (ICD) has increased to more than 200,000 implants worldwide to date. Indications for ICD implant have expanded to include both patients who have survived sudden cardiac death (secondary prevention of cardiac arrest) and those who are at high risk for experiencing lethal arrhythmias (primary prevention of cardiac ar rest). Thus, it is likely that physicians will encounter defibrillators in their clinical practice and must be familiar with their indications for implant, basic opera tion, and long-term management of devices. Several prospective clinical trials have recently shown the long- term efficacy of ICD therapy at aborting sudden death in the high-risk patient population. Although still evolving, general guidelines and indications for ICD implant have been put forth and are discussed in this review. From the first defibrillation in humans during surgery in 1947 to the sophisticated dual-chamber pacing and memory functions of the modern device, ICD development has led to ever smaller devices with more complex technol ogy. The implant procedure of current ICDs parallels that used to place pacemakers. However, the anesthe sia team plays a vital role in initial ICD implantation by monitoring cardiopulmonary status during defibrilla tion threshold (DFT) testing. Additionally, long-term management of ICDs often requires repeat DFT testing with anesthesia involvement. Finally, possible electro magnetic (environmental) interactions with the ICD of which physicians should be aware are described in this article.

Hemodynamic and antiadrenergic effects of dronedarone and amiodarone in animals with a healed myocardial infarction

The hemodynamic and antiadrenergic effects of dronedarone, a noniodinated compound structurally related to amiodarone, were compared with those of amiodarone after prolonged oral administration, both at rest and during sympathetic stimulation in conscious dogs with a healed myocardial infarction. All dogs (n = 6) randomly received orally dronedarone (10 and 30 mg/kg), amiodarone (10 and 30 mg/kg), and placebo twice daily for 7 days, with a 3-week washout between consecutive treatments. Heart rate (HR), mean arterial pressure (MBP), positive rate of increase of left ventricular pressure (+LVdP/dt), echocardiographically assessed left ventricular ejection fraction (LVEF), and fractional shortening (FS), as well as chronotropic response to isoproterenol and exercise-induced sympathetic stimulation were evaluated under baseline and posttreatment conditions. Resting values of LVEF, FS, +LVdP/dt, and MBP remained unchanged whatever the drug and the dosing regimen, whereas resting HR was significantly and dose-dependently lowered after dronedarone and to a lesser extent after amiodarone. Both dronedarone and amiodarone significantly reduced the exercise-induced tachycardia and, at the highest dose, decreased the isoproterenol-induced tachycardia. Thus, dronedarone and amiodarone displayed a similar level of antiadrenergic effect and did not impair the resting left ventricular function. Consequently, dronedarone might be particularly suitable for the treatment and prevention of various clinical arrhythmias, without compromising the left ventricular function.

New advances in class III antiarrhythmic drug therapy

In the past 2 years, significant advances have been made in class III antiarrhythmic drug therapy. In patients with ventricular arrhythmias and implantable cardioverter defibrillators (ICDs), antiarrhythmic agents are increasingly being used as adjunct therapy to decrease the frequency of ICD discharges. Sotalol was recently shown to be effective in reducing tachyarrhythmias in patients with ICDs. Intravenous amiodarone is being used for the acute treatment of unstable ventricular arrhythmia and is being investigated for the treatment of acute out-of-hospital cardiac arrest. Class III agents are increasingly being used for prophylaxis in patients who have atrial fibrillation or atrial flutter, and data point to an important role for these agents in reducing supraventricular tachyarrhythmias after cardiac surgery. Future studies will need to directly compare these agents with pure anti-adrenergic maneuvers in postoperative patients. In addition to terminating atrial fibrillation and atrial flutter, ibutilide significantly reduces human atrial defibrillation thresholds and increases the percentage of patients who can be cardioverted from atrial fibrillation to sinus rhythm. The US Food and Drug Administration is expected to approve dofetilide for clinical use soon, and it is currently reviewing azimilide (which seems to be devoid of frequency-dependent effects on repolarization) for prophylaxis against atrial fibrillation and atrial flutter. Dronedarone, tedisamal, and trecetilide are now under active study intended to determine their usefulness in patients with cardiac arrhythmias. Experimental studies are ongoing to identify pharmacologic agents that will selectively prolong repolarization in the atria without exerting electrophysiologic effects in the ventricles.

The MUSTT study: evaluating testing and treatment

The multicenter unsustained tachycardia trial (MUSTT) tested the value of electrophysiologically guided antiarrhythmic drug therapy against no therapy in high risk coronary artery disease with poor left ventricular function (LV-EF </= 40%) and nonsustained ventricular tachycardia. Risk assessment was performed by testing inducibility of a sustained ventricular tachycardia. The primary endpoint of the study was sudden arrhythmic death or cardiac arrest. Significant information on risk stratification was gathered by the follow-up of patients that were noninducible. Although MUSTT was not a specific ICD trial for primary prevention of SCD the results of the trial revealed that only with ICD back-upa significant reduction of arrhythmic death or cardiac arrest can be achieved.EP-guided antiarrhythmic drug treatment had a lower incidence of SCD/CA compared to no treatment (12% versus 25%, p = 0.043, hazard ratio 0. 73 after 24 months and 18% versus 32% after 60 months). A subgroup analysis showed that the benefit of antiarrhythmic treatment was only due to ICD implantation. No difference was found between those inducible pts treated exclusively with antiarrhythmic drugs and those who were randomized to no drug treatment. Patients who were not inducible did significantly better than pts who were inducible wether or not treated with antiarrhythmic drugs.MUSTT results strengthen the data of the MADIT study. They confirm the inducibility testing as the most accurate risk stratifier. MUSST demonstrated the poor value of serial EP drug testing as well as the risk of stand alone antiarrhythmic drug treatment.

Amiodarone: clinical trials

Amiodarone is an antiarrhythmic agent commonly used in the treatment of supraventricular and ventricular tachyarrhythmias. This article reviews the results and clinical implications of primary and secondary prevention trials in which amiodarone was used in one of the treatment arms. Key post-myocardial infarction primary prevention trials include the European Myocardial Infarct Amiodarone Trial (EMIAT) and the Canadian Amiodarone Myocardial Infarction Trial (CAMIAT), both of which demonstrated that amiodarone reduced arrhythmic but not overall mortality. In congestive heart failure patients, amiodarone was studied as a primary prevention strategy in two pivotal trials: Grupo de Estudio de la Sobrevida en la Insuficiencia Cardiac en Argentina (GESICA) and Amiodarone in Patients With Congestive Heart Failure and Asymptomatic Ventricular Arrhythmia (CHF-STAT). Amiodarone was associated with a neutral overall survival and a trend toward improved survival in nonischemic cardiomyopathy patients in CHF/STAT and improved survival in GESICA. In post-myocardial infarction patients with nonsustained ventricular tachycardia and a depressed ejection fraction, the Multicenter Automatic Defibrillator Implantation Trial (MADIT) demonstrated that implantable cardioverter-defibrillators (ICD) statistically improved survival compared to the antiarrhythmic drug arm, most of whose patients were taking amiodarone. In patients with histories of sustained ventricular tachycardia or ventricular fibrillation, the Cardiac Arrest Study in Seattle: Conventional Versus Amiodarone Drug Evaluation (CASCADE) trial demonstrated that empiric amiodarone lowered arrhythmic recurrence rates compared to other drugs guided by serial Holter or electrophysiologic studies. However, arrhythmic death rates were high in both treatment arms of the study. Several secondary prevention trials, including the Antiarrhythmics Versus Implantable Defibrillators Study (AVID), the Canadian Implantable Defibrillator Study (CIDS), and the Cardiac Arrest Study Hamburg (CASH), have demonstrated the superiority of ICD therapy compared to empiric amiodarone in improving overall survival. Based on the above findings, amiodarone is safe to use in post-myocardial infarction and congestive heart failure patients that need antiarrhythmic therapy. Although amiodarone is effective in treating malignant arrhythmias, high-risk patients should be considered for an ICD as frontline therapy.

Antiarrhythmic drugs or implantable cardioverter defibrillators in heart failure: the "poor heart"

Ventricular tachycardia and ventricular fibrillation account for a substantial proportion of all deaths in patients with heart failure. Of currently available therapies, amiodarone and the implantable cardioverter defibrillator (ICD) appear to have the greatest potential to decrease sudden death in heart failure. In this article, the presently available information on the relative role of antiarrhythmic drugs, with a focus on amiodarone and ICDs in heart failure, is reviewed.