High degree AV block complicating cardiac surgery or interventional catheterization: Longterm follow-up of underlying AV-conduction status after pacemaker implantation

Longterm Follow-Up of Underlying AV-Conduction Status After Pacemaker Implantation. This is a retrospective report on 38 patients (pts) with different cardiac diseases who underwent pacemaker implantation because of high (2 degrees and 3 degrees) degree atrioventricular (AV) block complicating cardiac surgery or catheterization. The study followed to objects: to describe a typical population affected with this complication and to investigate the chronic postoperative time course of intrinsic AV conduction after pacemaker implantation. Twenty-nine adults and 9 children were investigated. Surgical procedures in the adult group were aortic valve replacement (n=15), mitral valve replacement (n=6), mitral and aortic valve replacement (n=2) and coronary artery bypass grafting alone in 4 pts. One patient underwent balloon aortic valvotomy, another patient with HOCM had percutaneous transcoronary septal branch occlusion. 38% of all adult patients had intraventricular conduction defects prior to the operation which caused AV block. Indications for pacing were postoperative 2 degrees AV block in 4 pts and 3 degrees AV block in 25 pts. In the children's group 5/9 pts had surgical repair of ventricular septal defect, two pts underwent outflow tract myectomy, one child had correction of a partial AV canal and another one underwent arterial switch operation. All children postoperatively revealed complete heart block. Long-term follow-up (adult group: 37 months, children: 196 months) of the intrinsic heart rhyhtm after permanent pacemaker implantation revealed presence of high degree AV block in almost all (96%) adult patients and in the majority (67%) of children, who had high degree AV block documented by multiple routine ECG recordings following surgery or catheter intervention. In a small subgroup of 6 adult patients with a short intermittent loss of AV conduction in the postoperative period, AV conduction recovered and no episode of high degree block could be found during follow-up.