Ventricular tachycardia and ventricular fibrillation are recognized complications of cardiac catheterization. Despite numerous reports documenting the frequency of these occurrences, their significance has not been systematically examined. Accordingly, the outcome of 108 patients who experienced either ventricular tachycardia or ventricular fibrillation during coronary angiography between 1975 and 1979 in the Coronary Artery Surgery Study (CASS) Registry were examined. There were 20,142 patients analyzed. Patients with ventricular tachyarrhythmias had more objective evidence of left ventricular impairment, clinical heart failure, and ventricular arrhythmia recorded as a clinical symptom. The overall 5-year survival rates were 83% and 88% for patients with and without ventricular tachyarrhythmias, respectively (p = 0.07). When ventricular function, age, gender, angina, and previous myocardial infarction were added in a stepwise Cox survival analysis, the presence of arrhythmias was not significant (p = 0.66). At 5 years, 80% of the medically treated patients and 82% of the surgically treated patients remained alive (p = 0.95). The only statistically significant differences in the patients with ventricular arrhythmias who were treated medically or surgically were age (medically treated patients 52 +/- 10 years, surgical patients 57 +/- 9 years, p = 0.01) and number of diseased vessels (p less than 0.001). In a stepwise Cox survival analysis, functional impairment secondary to congestive heart failure was the only significant covariate to affect survival in the medical and surgical groups (p = 0.0001). Surgical therapy itself was not significant (p = 1.00). The incidence of sudden death during 5 years for patients with and without ventricular tachyarrhythmias during catheterization was 5% and 4%, respectively (p = 0.28).(ABSTRACT TRUNCATED AT 250 WORDS)