To determine the correlation of regional contraction abnormalities with ventricular activation in patients with coronary artery disease, intraoperative epicardial mapping was performed in 24 patients who underwent surgery for coronary artery disease. The results were compared with ventriculographic findings. Nine patients had normally contracting ventricles, 5 had areas of hypokinesis and 10 had areas of akinesis or dyskinesis. Four patients with asynergy had documented ventricular tachycardia or fibrillation. The earliest epicardial activation occurred in the anterior right ventricle in patients with and without asynergy. Each patient with normal contraction or areas of hypokinesis had 2 left ventricular epicardial breakthrough sites, whereas patients with areas of akinesis or dyskinesis had an average of 1.2 ± 0.6 left ventricular epicardial breakthrough sites (p < 0.05). Breakthrough did not occur in areas of akinesis or dyskinesis. The latest epicardial activation occurred at the base of either ventricle in all patients with normal ventricles or areas of hypokinesis, but in only 4 of 10 patients with akinesis or dyskinesis (p < 0.05). In 6 of 10 patients with akinesis or dyskinesis, the latest activation was over an abnormally contracting segment. Regional activation time in hypokinetic zones was not significantly delayed in akinetic and dyskinetic zones. Among patients with asynergy, there was no difference in epicardial activation pattern between those with and those without malignant arrhythmias. It is concluded that akinesis and dyskinesis, but not hypokinesis, are associated with marked changes in epicardial activation patterns.