Late outcome of survivors of out-of-hospital cardiac arrest with left ventricular ejection fractions greater than or equal to 50% and without significant coronary arterial narrowing. In a retrospective survey of 1,195 survivors of out-of-hospital ventricular fibrillation, 43 patients were identified in whom left ventricular ejection fraction was greater than or equal to 0.50 and in whom no coronary artery stenosis of greater than or equal to 50% luminal diameter were present. Thirteen (30%) of these patients had hypokinesia on left ventriculography, and 20 patients (47%) had a persistently abnormal electrocardiogram. Seven patients (16%) had recurrent out-of-hospital cardiac arrest during an average follow-up of 86 +/- 54 months. The presence of either wall motion or electrocardiographic abnormalities defined patients with a several-fold higher risk of recurrent cardiac arrest than those without such abnormalities. The risk for recurrent cardiac arrest within 5 years was 30% in those with abnormal electrocardiograms versus 5% in the others (p less than 0.03). Age was an independent predictor of recurrent cardiac arrest in this group (p less than 0.01); surprisingly, recurrent cardiac arrest was occurring more often among younger patients. Although cardiac arrest is unusual in patients without major structural heart disease, its recurrence in such survivors is common. Patients at relatively high risk for recurrent ventricular fibrillation can be identified by their youth and by abnormalities detected on the surface 12-lead electrocardiogram or by contrast left ventriculography. 