Circulatory failure has long been recognized as a frequent cause of death in cases of diphtheria. Investigators differ as to the exact mechanism of this process. Some believe that the fall of blood pressure and the circulatory collapse is a result of a myocardial weakness, while others insist that it is due to primary failure of the vasomotor apparatus, either central or peripheral.
Electrocardiographic studies1 made during the acute stage of the infection show evidences of myocardial damage in a majority of cases. Changes during the acute period are chiefly those of disturbances in auriculoventricular and intraventricular conduction. It is well known that in the late and convalescent periods, an acute collapse or sudden death may occur, usually after slight exertion. There are no reliable clinical criteria by which such a cardiac involvement may be detected during this stage. With a view of determining whether the string galvanometer may give