The indications for prophylactically placing implantable cardioverter defibrillator (ICD) patches at cardiac surgery are unclear. Over the past 4 years, 25 patients have undergone placement of prophylactic ICD patches at the authors' institution. Indications were severe coronary artery disease with ventricular tachycardia (VT) (n = 14) or ventricular fibrillation (VF) (n = 2), and left ventricular aneurysmectomy and/or subendocardial resection (SER) (n = 9). Four patients died in-hospital, three from refractory VT (which could be transthoracically cardioverted until recurrence was unremitting), and one from congestive heart failure (CHF). All of the remaining 21 patients underwent post-operative electrophysiologic studies (EPS), and 12 had inducible VT (8/14 CABG, 4/7 SER). Eight of the 12 inducible patients had generators implanted, whereas 3 patients were controlled medically. One patient refused generator implantation and died at home from sudden cardiac death, and one initially non-inducible patient required late ICD generator placement, yielding a total of nine patients who received generators. All nine of these patients are currently alive at 14 +/- 7 months follow-up, and five have subsequently received appropriate ICD discharges. In patients undergoing cardiac surgery considered preoperatively or intraoperatively to be at increased risk for VT/VF and too unstable for preoperative EPS, prophylactic ICD patches should be considered.