Survival after closed-chest ablation of His bundle with DC shock for supraventricular arrhythmias was analyzed for a 10-year period (May 1982-December 1992) with 317 consecutive patients (167 males, 150 females; mean age 66 years; range 33-93 years). Of these, 54 patients died (17.3%) and 5 were lost to follow-up. The mean age at ablation was 70.3 +/- 8.3 years with a range of 49-93 years. Of those who died, the mean survival was 30.5 +/- 28.6 months with a range of 36 hours to 120 months; the diagnosis of heart disease was: hypertension (n = 14), cardiomyopathy (n = 8), ischemic (n = 7), valvular (n = 6), cor pulmonale (n = 3), valvular and ischemic (n = 2), hypertension and ischemic (n = 1), miscellaneous (n = 3), and none (n = 10). Of the patients who died after ablation, the arrhythmias at the time of the ablation were atrial fibrillation (AF; n = 33), sick sinus syndrome (n = 5), atrial flutter (AFL; n = 4), paroxysmal AV junctional tachycardia (PAVJT; n = 4), AF + AFL (n = 4), atrial tachycardia (n = 2), PAVJT + AFL (n = 1), and AF +AFL + atrial tachycardia (n = 1). Death was sudden in 13 patients (25%), due to heart failure in 10 (19.2%), myocardial infarction in 4 (7.7%), stroke in 4 (7.7%), aortic vascular accident in 3 (5.8%), miscellaneous in 18 (34.6%), and undetermined in 2.(ABSTRACT TRUNCATED AT 250 WORDS)