Chronic His bundle block. Clinical, electrocardiographic, electrophysiological, and follow-up studies on 16 patients

Abstract

This report describes 16 patients with block within the His bundle seen over a period of 55 months. Ten were women and 6 men, with an average age of 76 years, range, 42 to 98 years. All patients had His bundle recordings showing split His bundle potentials ( Hand H') (13 patients) or narrow QRS with block distal to the His bundle potential (3 patients). Of the 16 patients, 10 had complete heart block, 4 second degree AV block (2 patients with Mobitz type II, A and 2 with 2:1), and 2firsVt degree block. Ten patients had a narrow QRS in the conducted beats or escape rhythms. Intravenous atropine (1 to 2 mg) had a variable effect on A V conduction and the rate of the escape rhythm. Twelve patients have had a permanent pacemaker implanted. During the follow-up period, 10 patients died 1 to 31 months from the time of initial examination. The remaining 6 patients (5 with pacemaker) are alive 3 to 58 months later.