Intermittent complete left bundle-branch block: phonocardiographic and mechanocardiographic study of one case.

Since the work of Wolferth and Margolies (1935), the modifications of both the heart sounds and the sequence of ventricular events induced by left bundle-branch block have been well known. Yet there has been some disagreement on details, mainly because left bundle-branch block is seldom aft isolated abnormality. The opportunity was offered to record the heart sounds, the indirect carotid pulse, and the apex cardiogram in the same patient, in conditions of both normal and abnormal left intraventricular conduction, making it possible to describe the changes due to the complete bundlebranch block alone.