Curves from a case of transient complete heart block,showing constantly varying ventricular complexes

Abstract

The patient from whom the curves were taken has been under observation since August, 1910. He was at that time suffering from cardiac decompensation. It was clear from the physical examination that he had a valvular defect. Combined arterial and venous curves were made. These showed that for short periods every impulse from the auricles was answered by a ventricular contraction, while at others the ventricular contractions responded to every second beat of the auricles. Curves were taken in February and March, 1911. These were volume curves from the jugular vein and radial artery and likewise curves of the cardiac action current, registered with an Edelmann stringgalvanometer. At first the ventricles responded to every second auricular beat, but somewhat later there was complete dissociation between the two pairs of cavities. Before the patient left the hospital, the relation between the auricles and ventricles was normal. Electric curves were taken on December 19, 1911, when the ventricles responded to every auricular contraction.

The curves which are of interest date from the period of complete auriculo-ventricular dissociation. Each ventricular complex is represented by R-, S-, and T-waves. They vary from each other in that, when the R- is large, the S-wave is small; and that when the S-wave is large, the R-wave is small. The R-wave gradually increases in size and then gradually diminishes, when the S-wave gradually increases in size and as gradually diminishes. If the apexes of succeeding R- and S-waves, i. e., the significant wave in each complex were joined, a waved line would result. So diagrammatic a sequence as this did not occur frequently, but there was a tendency to approximate to this description. Sometimes the transition from complexes of one type to those of another was abrupt.