Antiarrhythmics versus Implantable Defribrillators (AVID)

Objectives:

To evaluate if use of an implantable cardiac defibrillator (ICD) results in reduction in total mortality, when compared with conventional pharmacological therapy, in patients resuscitated from sudden cardiac death who are otherwise at very high risk of mortality from arrhythmic causes.

Background:

Sudden cardiac death is believed to account for a substantial portion of deaths with evidence of cardiovascular disease. The majority of sudden cardiac deaths are thought to be due to ventricular fibrillation or tachycardia. Currently the most common approach to preventing sudden cardiac death has been using drugs that suppress ventricular ectopy. However, given the disappointing results of most pharmacologic approaches to preventing sudden death, many investigators have turned to non-pharmacologic approaches such as surgery (endocardial resection, stellate ganglionectomy) or the implantation of devices that recognize VT or VF and deliver a shock. The greatest interest has been generated by work on the implantable cardiac defibrillator.

Subjects:

The study was designed in two phases. The pilot phase enrolled 200 patients between June 194 and June 1994. Data collected during the pilot phase cofirmed the trial was feasible. An additional 1,000 patients was subsequently enrolled.

Design:

At approximately 28 clinical sites, patients with ventricular tachycardia or ventricular fibrillation were screened. Patients meeting the criteria were randomized to treatment with an ICD or treatment with antiarrhythmic drug therapy. Patients were followed every 3 months for assessment of secondary endpoints, to record therapies delivered by the ICD and potential adverse effects of the ICD, and to assess compliance and potential adverse symptoms in patients treated with anti arrhythmic drugs.