Causes of death in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial

OBJECTIVES This study analyzed the causes of death in the Antiarrhythmics V ersus Implantable Defibrillators (AVID) Trial. BACKGROUND Both implantable cardioverter-defibrillators (ICDs) and antiarrh ythmic drugs (AADs) are used as mainstays of treatment for life-threatening ventricular arrhythmias in patients who have survived either ventricular f ibrillation or sustained ventricular tachycardia with hemodynamic compromis e and serious syptoms. The AVID Trial compared the effectiveness of these t wo therapies. Survival was better with the ICD. Assessment of the cause of death should help to determine the mechanism of improvement in survival wit h the ICD. METHODS Of 1,016 patients enrolled in the AVID Trial. 202 patients died. Th e mode of death was determined by the unblinded Principal Investigator and independently by an Events Committee, which reviewed materials meticulously blinded with respect to treatment. Deaths were classified as cardiac or no ncardiac. Cardiac deaths were further classified as arrhythmic or nonarrhyt hmic, and causes of noncardiac death were identified. RESULTS Deaths were more frequent in patients treated with an AAD (n = 122) , compared with patients treated with the ICD (n = 80), unadjusted p < 0.00 1, p = 0.012 adjusted for sequential monitoring. In AVID, 157 deaths were c ardiac, and 79 were arrhythmic, The major effect of the ICD was to prevent arrhythmic death (AAD = 55, ICD = 23, nominal unadjusted p < 0.001). Nonarr hythmic cardiac deaths were equal (AAD = 39, ICD = 39). Patients treated wi th an AAD had a slightly greater incidence of noncardiac deaths (28 vs. 17, p = 0.053), primarily due to pulmonary and renal causes. CONCLUSIONS The ICD is more effective than an AAD in reducing arrhythmic ca rdiac death, while nonarrhythmic cardiac death is unchanged. Of note, appar ent arrhythmic death still seems to constitute 38% of all cardiac deaths de spite treatment with an ICD. However, the ICD remains superior to an AAD in prolonging survival after life-threatening arrhythmias. (C) 1999 by the Am erican College of Cardiology.