Cardiac Arrest in Seattle: Conventional Versus Amiodarone Drug Evaluation (the CASCADE study). This randomized study evaluates survivors of out-of-hospital ventricular fibrillation (VF) not associated with a Q-wave acute myocardial infarction who are deemed to be at a high risk of recurrence of VF. It compares the outcome of treatment with empirically administered amiodarone with the outcome of treatment with other antiarrhythmic agents guided by electrophysiologic testing or Holter recording, or both. The goal of therapy guided by electrophysiologic testing is to suppress inducible ventricular tachycardia (VT) or VF. Holter recording is used as the primary means of adjusting therapy only if patients are noninducible at the baseline electrophysiologic study. Patients are stratified according to cardiac diagnosis, ejection fraction, and whether they had previously received an antiarrhythmic agent that failed to suppress their arrhythmias. The primary end point of the study is total cardiac mortality. The first patient was enrolled in a pilot study on April 26, 1984. By October 1988, 142 patients had been enrolled in the full study and, as of May 1990, 199 patients have been enrolled. Compliance with therapy has been good, with no patients lost to follow-up and 8% of patients, equal in both drug groups, crossing over to alternate therapy. Baseline clinical characteristics remain similar in amiodarone and conventional drug groups. Pulmonary toxicity with amiodarone is 7% at 1 year, with no patients dying of pulmonary toxicity. In the first 142 patients, the overall 1-year cardiac mortality was 19%, with a 17% arrhythmic mortality (either VF or presumed arrhythmic death). 