It is now well known that auriculoventricular conduction is frequently impaired in the course of rheumatic fever and that this disturbance affords valuable evidence of myocardial involvement.1 In a number of instances of partial or complete heart block2 and in one case showing only prolonged auriculoventricular conduction,3 postmortem examination of the heart has disclosed characteristic rheumatic lesions involving the auriculoventricular node or bundle. Such lesions have consisted of cellular infiltration and edema during the acute stages of the disease, or of scar tissue after healing has taken place. The transitory nature of conduction disturbances in many cases indicates that the inflammatory process may subside without graphic evidence of permanent damage to the heart muscle.
In following a series of cases of rheumatic fever in which frequent electrocardiograms were made, the diagnostic importance of disturbances in auriculoventricular conduction became apparent. The present study covers a period of nine years. Most of