The influence of respiration and of vagal stimulation on the location of the cardiac pacemaker and on the form of the ventricular electrocardiogram has been reviewed by Wilson,1 and need not be detailed here. In brief, so far as man is concerned, the pacemaker may be displaced from its normal location at the sino-auricular node to the auriculoventricular node, and vagal stimulation may affect the form of the ventricular electrocardiogram by producing a bundle branch block. In the case described below, marked alterations in the cardiac mechanism were associated with Cheyne-Stokes respiration and were brought about by vagal stimulation. In this instance, changes in the form of the ventricular complexes were due to displacement of the pacemaker into the branches of the His bundle, and it is the purpose of this paper to report such a disturbance in the cardiac mechanism.
REPORT OF CASE
The patient, a colored man, aged