Left anterior hemiblock in adult Africans.

A total of 4,000 consecutive electrocardiograms covering an 8-yr period was studied and all cases with pure left anterior hemiblock reviewed on the basis of clinical diagnosis and subsequent follow-ups. There were 66 cases in all, representing 1.6% of the total series with an age range of 30--81 and a mean of 53.4 yr; 43 males to 23 females--a ratio of approximately 2 : 1. 34 cases (51.5%) were hypertensives all with a minimum diastolic pressure of 120 mm Hg before treatment. Congestive cardiomyopathy accounted for 16 cases (24.3%) and diabetes mellitus unassociated with other ailments for another 6 cases (9.1%). Other causes included mixed aortic valve disease with 2 cases (3%), endomyocardial fibrosis with 2 cases (3%). In 6 patients (9.1%), all above the age of 70, who had been admitted for minor surgical operations, no cause could be found. This etiological pattern differs from that seen in white populations where ischemic heart disease is by far the commonest cause. The extreme rarity to left anterior hemiblock in rheumatic mitral valve disease is considered of help in separating cases of lone rheumatic regurgitation from those of mitral regurgitation complicating congestive cardiomyopathy if and when diagnostic difficulty arises.