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To determine the relation between the intraoperative defibrillation threshold and successful postoperative termination of induced ventricular fibrillation (VF) with the automatic implantable cardioverter defibrillator (AICD), 33 patients who underwent AICD implantation were studied. The defibrillation threshold, determined after at least 10 seconds of VF, was 5 J in 2, 10 J in 6, 15 J in 10, 20 J in 10 and 25 J in 5 patients. The AICD energy rating on the first discharge was 28 +/- 1.8 J. Defibrillation of induced VF was demonstrated postoperatively in 29 of 33 (88%) patients. The AICD terminated VF postoperatively in all 18 patients with a defibrillation threshold less than or equal to 15 J. Only 11 of the 15 (73%) patients with a defibrillation threshold greater than or equal to 20 J (p less than 0.04) had VF terminated postoperatively. In all 4 patients in whom the AICD failed to terminate induced VF, the energy difference between the AICD rating and the defibrillation threshold was less than or equal to 10 J. Among the 14 patients with a difference of less than or equal to 10 J between the AICD energy rating and the defibrillation threshold, there were no significant differences between the 4 patients with and the 10 without successful VF termination with respect to the duration of VF induced postoperatively or the AICD lead system. In summary, failure to terminate VF with the AICD is not uncommon (27%) when the defibrillation threshold approaches the energy delivering capacity of the AICD.(ABSTRACT TRUNCATED AT 250 WORDS)

Subendocardial resection and implantation of an automatic implantable cardioverter/defibrillator are the current preferred treatments for the management of drug-resistant malignant ventricular arrhythmias and sudden cardiac death. We reviewed retrospectively the case histories of 269 patients who had subendocardial resection and 77 patients who had defibrillator implantation to define clinical characteristics of each group and compare operative and long-term results. All patients treated by subendocardial resection had recurrent sustained ventricular tachycardia as a result of a myocardial infarction. From the standpoint of arrhythmia substrate and cardiac disease, patients receiving the defibrillator were a more heterogeneous group. Forty-eight (62%) had coronary artery disease, 28 (36%) cardiomyopathy, and one patient had a primary electrical abnormality. Among patients receiving the defibrillator, 55% had sustained ventricular tachycardia and 45% polymorphic ventricular tachycardia or ventricular fibrillation. Overall ventricular function was similar in the two groups. Operative mortality rate was better in the group having defibrillator implantation (3% versus 15%). Complications related to the defibrillator device or implantation occurred in 46 (60%) patients, with asymptomatic shocks occurring in 35 patients (45%). Since the defibrillator was not designed to prevent arrhythmias, the arrhythmia-free survival rate was much better in the group having subendocardial resection (95% versus 44% at 3 years). Fewer patients treated by subendocardial resection required antiarrhythmic medications (33% versus 66%). The actuarial survival rate was similar in the two groups (approximately 60% at 4 years), with heart failure the most common cause of death. Thus both subendocardial resection and defibrillator implantation are highly effective in preventing sudden cardiac death. The choice of procedure depends on (1) arrhythmia diagnosis, (2) cardiac disease, and (3) intangible factors.

Twenty-six patients with refractory ventricular arrhythmias received the automatic implantable cardioverter-defibrillator. A patch lead only was placed during arrhythmia surgery in 7 other patients. During 13 +/- 6 (SD) months, the device discharged in 10 patients because of a sustained ventricular arrhythmia. No sudden deaths occurred. There were 31 complications in 17 patients, including postoperative refractory heart failure, coronary artery erosion, subclavian vein thrombosis, postoperative stroke after conversion of atrial fibrillation, atelectasis with pneumonia, symptomatic pleural effusions, and infection at the generator site. The cardioverter-defibrillator discharged in 9 asymptomatic patients, failed to terminate ventricular fibrillation during postoperative testing in 3 patients, and had premature battery failure in 4 patients. Tachycardia slowing during chronic amiodarone therapy and unipolar ventricular pacing during ventricular fibrillation precluded or delayed arrhythmia sensing. Thus, the cardioverter-defibrillator can be life saving, but its potential complications and interactions with antiarrhythmic drugs and pacemakers must be considered at patient selection.

Clinical results are reviewed in 269 patients who underwent subendocardial resection for recurrent sustained ventricular tachycardia secondary to ischemic heart disease. Operative mortality is 15%. Factors increasing operative mortality rates are ejection fraction less than 20%, emergency operation, and history of previous heart operation. Use of amiodarone preoperatively does not alter operative risk. Clinical control of ventricular tachycardia is achieved in 93% of operative survivors. Two thirds of these patients do not need antiarrhythmic agents. Five-year actuarial survival is approximately 60%. Patient results with the automatic internal cardioverter defibrillator at the Hospital of the University of Pennsylvania and nationwide are also reviewed. As of June 1987, almost 1,500 patients had one or more devices implanted. Most patients had a prior documented cardiac arrest. Coronary artery disease is the cause of heart disease in over 70% of patients. Operative mortality is low (0.8-3.9%). Approximately 50% of patients have had therapeutic discharge of the device; however, asymptomatic discharge occurs in up to 45% of patients. Incidence of sudden death is 1.5% at 1 year and 5% at 5 years. Five-year actuarial survival is approximately 60%. Long-term mortality is primarily from heart failure.