We searched for randomized trials in MEDLINE (1980–24 September 2002), the Cochrane Controlled Clinical Trial Registry (2002, Volume 3), EMBASE (1980–2002), Web of Science, National Library of Medicine Gateway, Cardiosource, the Clinical Trials Registry, Clinicaltrials.gov, the CRISP (Computer Retrieval of Information on Scientific Projects) Database, the National Research Register, the Glaxo–Wellcome Clinical Trials Register, the LILACS (Latin American and Caribbean Health Science Literature) Database, OCLC (Online Computer Library Center) ProceedingsFirst, and the National Health Service Economic Evaluation Database. All databases were last accessed on 24 September 2002. In addition, bibliographies of relevant papers were hand searched and experts, device manufacturers, and primary authors were contacted for information on additional trials. Relevant conference proceedings were also searched. The search was not limited by language. We used the following textwords and Medical Subject Headings: ICD, AICD, implantable defibrillators (exp), heart arrest (exp), sudden cardiac death (exp), sudden death (exp), SCD, cardiac arrest, coronary disease (exp), heart disease (exp), systolic dysfunction, ventricular dysfunction (exp), heart failure (exp), ventric* arrhythmia, ventric* rhythm, ventric* fibrillation, ventric* tachycardia, arrhythmia (exp), anti-arrhythmia agents (exp), anti-arrhythmia drug*, anti-arrhythmia therap*, and antiarrhythmi*.