Mechanism of the Wolff-Parkinson-White Syndrome

The Wolff-Parkinson-White syndrome has been described frequently during the past few years, and there is considerable evidence now that the short P-R interval associated with an aberrant QRS is probably due to short circuiting of an auricular stimulus through one or more accessory bundles. Hunter, Papp, and Parkinson (1940) came to the conclusion that the syndrome represented a double rhythm by two interfering pacemakers, one near the sinus and the other in one bundle branch, but Wolferth and Wood (1941) raised objection to this hypothesis, and adhered to their previous theory (1933) put forward to explain this type of cardiogram, namely, that the ventricular asynchronism is due to premature stimulation of one ventricle by conduction through the bundle of Kent. Parkinson and others described gradual changes of P coinciding with gradual changes in the ventricular complex, and argued against the bundle of Kent hypothesis. Wolferth and Wood, however, thought there was as much variation between the P waves before aberrant as there was before normal complexes, and quoted a case of Tung (1936) in which the P waves became smaller and the QRS complexes normal twenty minutes after the injection of atropine; thirty minutes after the injection the P waves had returned