[Proceedings: Vectorcardiographic study of right bundle-branch block with left axis deviation].

The electrocardiographic pattern of right bundlebranch block in the precordial leads associated with left axis deviation in the limb leads has been noted by others. Wilson, Johnston, and Barker (1934) were the first to describe a small wide R and S wave in lead I, with a wide and deep S wave in leads II and III, and a typical RBBB pattern in the praecordial leads. Recently, Lepeschkin (1964) reviewed the various cardiographic and pathological alterations associated with this pattern. There now appears to be general agreement that the basic lesion consists ofpredominant right bundle-branch block associated with defects in the distribution of the left bundlebranch. Left and right ventricular hypertrophy, as well as infarction and fibrosis of variable location and extent, are frequently present (Lepeschkin, 1964). The present study was undertaken to determine whether additional and more specific information could be obtained under these circumstances by a detailed study of the spatial vectorcardiograph. The results obtained are the basis for a proposed classification of possible clinical utility.