ACTION OF DIGITALIS ON CONDUCTION IN THE SYNDROME OF SHORT PR INTERVAL AND PROLONGED QRS COMPLEX

Abstract

It is stated that the effect of digitalis on the heart can simulate almost every type of electrocardiographic abnormality due to cardiac disorders with the exception of intraventricular conduction defects.¹ As far as the normal electrocardiogram is concerned, this statement is undoubtedly true. The observations of Hart,² however, have been widely cited in the literature as indicating that digitalis may occasionally cause a delay in intraventricular conduction and a consequent widening of the QRS complex. In this study prolongation of the QRS time was produced by digitalis in the course of a clinical experiment. The observations were made in a case of so-called "bundle branch block with short PR interval," a syndrome first observed by Wilson³ and subsequently described by Wolff, Parkinson and White.⁴ Bishop⁵ more recently reviewed 45 cases of this syndrome reported in the literature, but as far as we are able to