INTERMITTENT BUNDLE-BRANCH BLOCK

Abstract

INTERMITTENT bundle-branch block, a not uncommon electrocardiographic finding, is encountered mainly in elderly people or patients with organic heart disease.¹ Rarely it is found in a person with an otherwise normal heart,² though its mere presence is taken by some³ to be evidence of heart disease. The rarity of this condition in the absence of heart disease was borne out by the study of Comeau, Hamilton, and White³ wherein they found only 6 patients of a total of 77 with intermittent bundle-branch block in whom myocardial disease could not be implicated. In reviewing the pertinent medical literature since Comeau's analysis, Sandberg and co-workers⁴ reached a similar conclusion; they found that only 6 patients of a total of 82 with intermittent bundle-branch block had no apparent heart disease. Because of the underlying disease in patients with this condition, the conducting system becomes so modified that a point is reached where even