Safety and feasibility of conduction system pacing in patients with congenital heart disease

Introduction Conduction system pacing (CSP) has emerged as an ideal physiologic pacing strategy for patients with permanent pacing indications. We sought to evaluate the safety and feasibility of CSP in a consecutive series of unselected patients with congenital heart disease (CHD). Methods Consecutive patients with CHD in which CSP was attempted were included. Safety and feasibility, implant tools and electrical parameters at implant and at follow-up were evaluated. Results A total of 20 patients were included (10 with a previous device). A total of 10 patients had complex forms of CHD, 9 moderate defects and 1 a simple defect. CSP was achieved in 75% of cases (10 His bundle pacing, 5 left bundle branch pacing) with left ventricular septal pacing in the remaining 5 patients. Procedure times and fluoroscopy times were prolongued (126 +/- 82 min and 27 +/- 30 min, respectively). Ventricular lead implant times widely varied ranging from 4 to 115 min, (mean 31 +/- 28 min) and the use of multiple delivery sheaths was frequent (50%). The QRS width was reduced from 145 +/- 36 ms at baseline to 116 +/- 18 ms with CSP. Implant electrical parameters included: CSP pacing threshold 0.95 +/- 0.65 V; R wave amplitude 9.2 +/- 8.8 mV and pacing impedance 632 +/- 183 Ohms, and remained stable at a median follow-up of 478 days (interquartile range: 225-567). Systemic ventricle systolic function and NYHA class (1.50 +/- 0.51 vs. 1.10 +/- 0.31; p = .008) significantly improved at follow-up. Lead revision was required in one patient at Day 4. Conclusions Permanent CSP is safe and feasible in patients with CHD although implant technique is complex.