Exercise-induced left bundle branch block: resolution after coronary angioplasty

Influence of underlying coronary artery disease on the natural history and prognosis of exercise-induced left bundle branch block

The long-term prognosis of exercise-induced left bundle branch block (BBB) in patients with and without underlying coronary artery disease (CAD) was examined by following 15 patients (7 with normal coronary arteries and 8 with CAD) for an average of 6.6 years (range 2.2 to 11.2). Over the follow-up interval, permanent left BBB developed in 8 of the 15 patients. Seven of these 8 had underlying CAD, compared to 0 of 6 patients with normal coronary arteries and normal left ventricular function (p less than 0.002). In 1 patient with normal coronary arteries and a left ventricular ejection fraction of 0.34, permanent left BBB developed. During follow-up, 4 patients died; 3 had significant CAD and 1 had depressed left ventricular function. In no patient did high-grade atrioventricular block develop and no patient required pacing. Thus, development of permanent left BBB in patients with exercise-induced left BBB is related to presence or absence of underlying CAD or myocardial disease. When left BBB is found in the absence of underlying heart disease, there does not tend to be progression of the conduction disturbance and the prognosis is excellent.

Exercise-induced left bundle branch block: resolution after calcium antagonist therapy

We describe a middle-aged man who developed angina and transient left bundle branch block during an exercise test. Coronary arteriography failed to shown significant atherosclerotic lesions and therapy with calcium antagonist nifedipine resolved both the symptoms and the electrocardiographic abnormalities. Previous reports of transient conduction defects have been related to severe obstructive lesions of the coronary arteries. The minimal lesions found in our patient suggest that coronary spasm may have been the causative mechanism.