Prolonged complete heart-block, without lesion of the bundle of His and with frequent changes in the idio-ventricular electrical complexes

Electrocardiograms were obtained at intervals from an old hemiplegic patient who was known to have complete heart-block from February 26, 1912, up to the day of his death, December 31 of the same year. During many months of this period he had pronounced Cheyne-Stokes respiration. The interest in this case lies in the fact that there were frequent changes in the electrical complexes of the ventricular beat and correlated with this the fact that histological examination revealed no organic lesion to account for the block, in the auriculo-nodal junction, the node of Tawara, or the main stem and its branches. The nodal artery was sclerotic.The variations in the ventricular complexes were seen not only from one examination to the next, but often from beat to beat.The waves Q, R, S and T all showed variations; for example with leads I and II the wave R was sometimes upright, sometimes inverted. With lead III the wave R was always inverted.The auricular rate was strikingly reduced during the dyspneic period (44.49 beats per minute), as compared with its rate during apnea (94.17 beats per minute). The ventricular rate was only slightly reduced during dyspnea (30.46 beats per minute as compared with 31.25 beats per minute). In other words the vagus still had a marked chronotropic effect on the auricle and little if any on the ventricle. Two atropin tests were made during which the heartblock was not relieved; and, again, the auricular rate was decidedly increased, the ventricular rate very slightly so.To explain the divergent types of ventricular complexes we may consider the possibility that the intrinsic ventricular pacemaker was frequently shifting, or that the different impulses started at the same point and traveled either along different routes, or at varying rates along the same route.