Out-of-hospital cardiac arrest: electrophysiologic observations and selection of long-term antiarrhythmic therapy.

We performed electrophysiologic studies in 31 survivors of out-of-hospital cardiac arrest not associated with acute myocardial infarction. At the time of resuscitation, eight patients had sustained ventricular tachycardia and 23 patients had ventricular fibrillation. Programmed right ventricular stimulation later revealed electrically inducible ventricular arrhythmias in 25 of the 31 patients (81 per cent). Complete suppression of electrically inducible ventricular arrhythmias was achieved with antiarrhythmic therapy in 19 of these 25 patients. None of the 19 patients in whom the inducible arrhythmias was suppressed before discharge has died suddenly or had a symptomatic arrhythmia after a mean follow-up of 15 months (range, five to 26 months). Of the six patients in whom inducible arrhythmias could not be suppressed, three died suddenly (one in the hospital) within six months. We conclude that ventricular arrhythmias can be initiated and reproduced by programmed ventricular stimulation in a majority of patients who have been resuscitated after out-of-hospital cardiac arrest and that complete suppression of these arrhythmias with anti-arrhythmic therapy is highly predictive of survival for at least one year.