Cause of atrioventricular block in patients after heart transplantation

The precise incidence and cause of atrioventricular block (AVB) after heart transplantation remain uncertain. After surgery, immediate and follow-up electrocardiograms from 1047 consecutive patients who underwent heart transplantation were reviewed for AVB and correlated with clinical symptoms, laboratory data, rejection grade, and echocardiogram and coronary angiography findings. A total of 113 patients demonstrated various kinds of AVB; the incidence was 10.8%. First-degree AVB occurred in 87 patients, 37 of whom also demonstrated persistent atrial tachyarrhythmias (ATAs). In 30 patients, first-degree AVB occurred 7 days to 120 months after heart transplantation. Among those, 88% demonstrated cellular rejection, and 20% developed transplant coronary artery disease (TCAD). Fifty patients demonstrated first-degree AVB without ATA, 32 of whom developed AVB from operative day 7 to 156 months. The incidence of cellular rejection was significantly lower (36%, P