Heart Block and the Simulation of Bundle Block in Diphtheria

Cardiographic studies in diphtheria show that a wide variety of arrhythmias and abnor- malities of pattern occur. Among these heart block is familiar, not so much because it is common, but because in its more severe forms it indicates a grave prognosis. Burkhardt, Eggleston, and Smith (1938) recorded 11 cases of A-V dissociation, all fatal; some presented a terminal ventricular tachycardia. They noted a high idio-ventricular rate of 80-90 so that block was not suspected before the cardiogram was taken.