title: Cause of atrioventricular block in patients after heart transplantation.
abstract: BACKGROUND
  The precise incidence and cause of atrioventricular block (AVB) after heart transplantation remain uncertain.
  
  
  RESULTS
  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<0.01), and the rejection was less severe. In 18 patients, AVB occurred early postoperatively (0-7 days), and most were secondary to surgical injury. Second-degree AVB Mobitz I occurred in six patients (four patients with TCAD and two patients undergoing percutaneous transluminal coronary angioplasty). One patient developed Mobitz II during coronary artery stenting. Complete AVB (CAVB) occurred in 19 patients. Nine episodes of CAVB occurred during endomyocardial biopsy or coronary angiography, and four occurred immediately after heart transplantation as the result of surgical insult.
  
  
  CONCLUSIONS
  These results indicate that first-degree AVB is causatively related to cellular rejection and TCAD-induced atrial conduction disturbance. Second-degree AVB and CAVB were mainly the consequences of surgical and catheter intervention injury.
authors.affiliation: Department of Medicine, UCLA Medical Center, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1679, USA.
authors.forename: Guanggen
authors.initials: G
authors.lastname: Cui
authors.forename: Jon
authors.initials: J
authors.lastname: Kobashigawa
authors.forename: Armen
authors.initials: A
authors.lastname: Margarian
authors.forename: Luyi
authors.initials: L
authors.lastname: Sen
mesh_terms: D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D017023:Coronary Angiography; D005500:Follow-Up Studies; D006084:Graft Rejection / Q000453:epidemiology; D006327:Heart Block / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality; D016027:Heart Transplantation / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D011183:Postoperative Complications / Q000209:etiology*; D011342:Procainamide / Q000627:therapeutic use; D011802:Quinidine / Q000627:therapeutic use; D012189:Retrospective Studies
chemical_list: D000889:Anti-Arrhythmia Agents; D011802:Quinidine; D011342:Procainamide