AVID trial

Exner, D., Reiffel, J., Epstein, A., Ledingham, R., Reiter, M., Yao, Q., Duff, H., Follmann, D., Schron, E., Greene, H., Carlson, M., Brodsky, M., Akiyama, T., Baessler, C., and Anderson, J., Beta-blocker use and survival in patients with ventricular fibrillation or symptomatic ventricular tachycardia The Antiarrhythmics Versus Implantable Defibrillators (AVID) trial, Journal of American College of Cardiology, Vol. 34, No. 2, 1999, pp. 325-333. 

The Antiarrhythmics versus Implantable Defibrillators (AVID) trial (7) was the largest secondary prevention trial, and helped define ICD implant indications for patients with a history of ventricular arrhythmias. In AVID, 1013 patients who presented with VF, sustained VT with syncope, or sustained VT with a LVEF of <40% were randomized to either an ICD or antiarrhythmic... 

The AVID trial, a large multicenter prospective NIH-sponsored trial, compared antiarrhythmic drug (amiodarone or sotalol) therapy to ICD implant in patients who survived life-threatening hemodynamically destabilizing ventricular arrhythmias (ventricular tachycardia and ventricnlar fibrillation). One thousand sixteen patients were randomized (45% with ventricnlar fibrillation and 55% with poorly tolerated ventricular tachycardia). The mean ejection fraction was 0.32. Patients with sustained ventricular tachycardia who were enrolled had associated syncope or a left ventricular ejection fraction < 0.40 (118). The AVID trial is the most persuasive and influential secondary prevention trial to date. At the time this trial was initiated, several centers refnsed to participate because of the belief that the ICD had already been shown to be the best therapy. Fifty-six U.S. and Canadian centers participated. 

Fig. 14.1 Survival curves for patients in the AVID trial. A significant survival benefit was observed with defibrillator therapy. AA, antiarrhythmic drug group. (From AVID investigators. N Engl J Med 1997 337 1576-1583, with permission.)...

At 24 months, there was a 15% mortality rate in the ICD arm versus a 20% mortality rate in the amiodarone arm. At 36 months, the mortality rate in the ICD arm was 25% and for the amiodarone arm was 30%. Mortality reduction was 19.6% at 3 years with the ICD (p = 0.072) (Fig. 14.2). The conclusions were consistent with the AVID trial but CDDS did not show a statistically significant benefit of an ICD for this population. In the CIDS trial, similar to the AVID trial, )3-blocker use was greater in patients randomized to ICD implantation. Older patients and less healthy patients derived the greatest benefit from an ICD. In CIDS, there was a high crossover rate 30% of the patients in the ICD arm also received amiodarone and 22% in the amiodarone arm received an ICD implant (171). 

Before the era of primary implantation, ICD therapy generally used to fit in the cost-effective range of 20,000- 40,000 (136,210-213). MushUn assessed incremental cost-effectiveness of ICD implant in the MADIT trial (214). After 4 years, ICD implants were associated with an incremental benefit of 0.8 years. Based on this survival benefit, the authors estimated that ICD cost was 22,800 for the 181 patients who received a transvenous device. The cost per life year saved for ICDs in the AVID trial was > 114,917. The reason for this extraordinarily high cost is, in part due to the short-term follow-up, and the short (2.9-month) survival advantage for the ICD group despite a 37% reduction in mortality. 

Following resuscitation from ventricular fibrillation (VF) or pulseless VT, ICD implantation is a proven strategy for the prevention of recurrent SCD. Three prospective, randomized, controlled trials, the Antiarrhythmics Versus Implantable Defibrillators (AVID) study, the Canadian Implantable Defibrillator Study (CIDS), and the Cardiac Arrest Study Hamburg (CASH), support this strategy [27-29]. 

A significant mortality benefit of ICD therapy was shown in the largest of the three studies, the AVID study. In this study, over 1,000 patients with ischemic cardiomyopathy and an EF < 40% who were resuscitated from VF or from symptomatic, sustained VT were randomized to antiarrhythmic medications (>90% amiodarone) or ICD implantation. The trial was stopped early because the ICD showed a significant survival benefit with an 11.3% absolute and 31.5% RR reduction for all-cause mortality over 3 years. Persistent benefit with the ICD was seen even after adjustment for age, beta blocker use, and baseline EF. 

AVID Antiarrhythmic drug Versus Internal Defibrillator trial CAST Cardiac Arrhythmia Suppression Trial DCC direct-current cardioversion EADs early after-depolarizations... 

Connolly SJ, Hallstrom AP, Cappato R, et al. Meta-analysis of the implantable cardioverter defibrillator secondary prevention trials AVID, CIDS, CASH studies. Eur Heart J 2000 21 (24) 2071—8. 

The original intent of the ICD was to prevent recurrent cardiac arrest due to ventricular tachycardia and fibrillation. Secondary prevention of recurrent cardiac arrest was initially the prime reason for ICD implant. Five multicenter prospective randomized secondary prevention trials have been completed AVID (Antiatrhythmics Versus Implantable Defibrillator), CASH (Cardiac Arrest Study Hamburg), CIDS (Canadian Implantable Defibrillator Study), DEBUT (Defibrillator versus beta-Blockers for Unexplained death in Thailand), and MAVERIC (The Midlands Trial of Empirical Amiodarone versus Electrophysiology-guided Interventions and Implantable (Tardioverter-defibrillators) (Table 14.3) (77,118,121,149,170). 

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