Late recovery of atrioventricular conduction after pacemaker implantation for complete heart block in congenital heart disease: fact or fluke?

Objectives : Pacemaker implantation is a standard recommendation for patients with persistent complete heart block with congenital heart disease. This study was performed to determine the incidence and clinical significance of late recovery of atrioventricular (AV) conduction following pacemaker implantation. Methods : A retrospective study of patients with congenital heart disease needing pacemaker implantation was performed between 1977 and 2008 at our institution. The postoperative course of all patients with complete heart block, in whom a permanent pacemaker was implanted, was followed on a semi-annual basis by clinical follow-up. Results : A total of 56 patients with complete heart block underwent pacemaker implantation. Indications for pacemaker implantation could be categorized in primary AV conduction block (n = 28; 50%) and surgically-induced AV conduction block (n = 28; 50%). After pacemaker insertion, recovery of AV conduction was recognized in two patients. The first patient was operated for atrial septal defect type ostium secundum with complete heart block preoperatively. AV block resolved 2 days after pacemaker implantation. The second patient underwent mitral valve replacement. Postoperatively, the patient developed second degree heart block, which progressed 3 years later into complete heart block. A recovery of AV conduction was seen 7.5 years later. In these patients, no late recurrence of complete heart block was found during follow-up after 8 and 4 months, respectively. Conclusions : Recovery of AV conduction was observed in one patient with primary AV conduction block and in one patient with complete heart block after congenital heart surgery. Lifelong cardiac pacing in these specific subsets of patients may not be necessary.