Comment on the implantable defibrillator backlash

Implantable cardioverter-defibrillator therapy in 300 patients with coronary artery disease presenting exclusively with ventricular fibrillation

To determine outcomes of implantable cardioverter-defibrillator (ICD) therapy in a uniform population of survivors of sudden cardiac death, we used epicardial defibrillation lead systems to study 300 patients with coronary artery disease (CAD) presenting exclusively with ventricular fibrillation (VF) unassociated with acute myocardial infarction. Operative (30-day) mortality, 2.7% overall, was lower (0.6%) in patients with ejection fractions (EF) > or = 0.30. Over a median follow-up of 1.9 years, cumulative actuarial shock incidence was similar in patients who underwent concomitant coronary artery bypass graft (CABG) surgery (38%) and in those who did not. The 2-year cumulative actuarial incidences of any or appropriate shocks were 65% and 38%, respectively. Sudden death survival at 2 years was 92.5% and 99.3% for patients with EFs < or = 0.30 and > 0.30, respectively. The total mortality rate was similar in shocked and in unshocked patients. Multivariate analysis identified EF and female gender as significant predictors of any and appropriate shock occurrence (all p values < or = 0.05) and EF as a significant predictor of sudden, cardiac, and total mortality (all p values < 0.03). We conclude that in CAD patients presenting exclusively with VF unassociated with acute myocardial infarction and treated with thoracotomy-requiring ICD therapy: (1) operative (30-day) mortality is minimal for patients with an EF > or = 0.30; (2) device use is high and sudden death rates low regardless of concomitant CABG; (3) low EF is a significant predictor of cumulative shock occurrence and mortality (sudden, cardiac, and total); (4) female gender may be a predictor of shock occurrence; and (5) similar mortalities and low sudden-death rates in shocked and nonshocked ICD patients imply that ICD therapy improves survival in shocked patients to a level observed in comparable patients in whom ventricular tachyarrhythmia does not recur.

Antiarrhythmic drugs versus implantable defibrillators: the need for a randomized controlled study

The implantable cardiac defibrillator was first used in 1980 and has gained widespread acceptance. However, no randomized controlled trials have been reported that compare the implantable cardiac defibrillator with antiarrhythmic drugs. Most published studies have used historical control subjects or nonrandomized concurrent patients for comparison with patients who received an implantable defibrillator. To reduce bias, studies are needed that compare therapies randomized between antiarrhythmic drugs and implantable defibrillators. The Antiarrhythmics Versus Implantable Defibrillators (AVID) Study was designed to evaluate the nonthoracotomy, tiered-therapy implantable defibrillator compared with drug therapy (amiodarone or sotalol). Patients are eligible for randomization if they have a history of recent cardiac arrest caused by ventricular fibrillation or have hemodynamically serious ventricular tachycardia. A pilot study to enroll 200 patients began on June 1, 1993, before the start of the main study of 1000 patients. Analysis of the main study by intention to treat will assess the primary endpoint of total mortality.

Prevention of sudden cardiac death: the ICD, or an electrical end-point with preceding opportunities for intervention?

Sudden cardiac death (SCD) is usually due to monomorphic ventricular tachycardia and/or ventricular fibrillation. However, in the vast majority of patients these arrhythmias are associated with advanced structural disease. In our society, this is usually due to coronary artery disease (CAD). The implantable cardioverter--defibrillator is the logical approach to management in survivors of SCD. Its rational use must be guided by electrophysiology study. However, a realistic and cost-effective approach to the prevention of a first cardiac arrest must be multifaceted and take cognisance of other aspects including primary prevention. Limitation of the size of myocardial infarction (MI) is vital. Trials already suggests that effective thrombolysis may impinge long-term on arrhythmic end-points. Following infarction, ventricular arrhythmias and sudden death may also be decreased by aspirin, beta-blockers, and possibly angiotensin converting enzyme inhibitors and amiodarone. Many post-infarction studies employ a combined end-point of death and clinical arrhythmias. However, death is usually confined to those with an ejection fraction < 35%. In them, treatment of associated heart failure is often a consideration and if the ejection fraction < 15-20%, depending on donor availability, transplantation may even be the preferred therapeutic option to the cardioverter-defibrillator.