Pathology of the conduction system in cardiac rejection.

Correlation of electrocardiographic abnormalities occurring postoperatively with lesions of the conduction system found at autopsy was done in 20 dogs which had received cardiac homografts. The incidence of arrhythmias closely paralleled the severity of rejection injury found within the heart and specifically within the conduction system. Severe pathological changes in the conduction system (grade D) were uniformly associated with arrhythmias. These disturbances, as well as decrease in electrocardiographic voltage, have consistent anatomic correlates in acute rejection of cardiac homografts and are of primary importance in the clinical diagnosis of acute rejection.