Endocardial atrial pacing lead, implantation and midterm follow-up in young patients with sinus node dysfunction after the Fontan procedure

The purpose of the study was to investigate the results of endocardial lead implantation, lead performance, and follow-up in young patients after the Fontan procedure. A retrospective study was conducted with patients who had endocardial atrial pacing for SND and intact AVN function after Fontan from two pediatric centers. Patient demographics, pacing, and sensing data of endocardial atrial leads were analyzed at the time of pacemaker implantation and follow-up visits. Fifteen patients (weight 42.6 +/- 35 kg) had transvenous endocardial atrial lead implantation at an average age of 11.4 +/- 6.5 years. Active-fixation leads were used in all patients and steroid elution was present in 12 (80%) patients. Adequate P wave sensing was obtained in patients with sinus rhythm (n = 10); the remaining four patients had junctional rhythm without measurable P waves. Lead failure was not observed in any patient during the follow-up period of 2.9 +/- 2.1 years. The energy threshold at implantation was 1.46 +/- 1.5 muJ, 1.54 +/- 0.75 muJ at 3 months, 0.62 +/- 0.45 muJ at 1 year, 0.72 +/- 0.65 muJ at 2 years, 0.75 +/- 0.55 muJ at 3 years, and 0.8 +/- 0.85 muJ at 5 years postimplant. The lead impedance was 648 +/- 298 Omega at implantation, 714 +/- 163 Omega at 3 months, 744 +/- 195 Omega at 1 year, 734 +/- 198 Omega at 2 years, 800 +/- 142 Omega at 3 years and 830 +/- 200 Omega 5 years postimplant. Anticoagulation therapy (aspirin n = 5, warfarin n = 8) was continued by 13 patients. Complications consisted of a pneumothorax at implantation and a transient ischemic attack in one patient 4 years after pacemaker implant. Endocardial atrial leads offer low energy thresholds and can be implanted relatively safely in Fontan patients.