Learning Curve for Left Bundle Branch Area Pacing – the Experience of a Romanian Academic Center

Abstract

Introduction: There is an increasing interest in the past decade for more physiological pacing strategies due to detrimental long-term right ventricular pacing. His bundle pacing is the most physiological one, but it has some drawbacks, mainly an increased pacing threshold. Left bundle branch area pacing (LBBAP) emerged in the recent years as the next step in conduction system pacing. We present our initial experience and learning curve with this latter procedure. Material and methods: During January 2019 and February 2021, 20 patients with pacing indications that failed initial permanent His bundle pacing underwent successful LBBAP. Results: The mean age was 65.9 ± 12.7 years. The indications for cardiac pacing were AV block in 14 patients(70%) and cardiac resynchronization therapy in 6 patients (30%). At baseline, normal QRS complex was noted in 9 patients, a left bundle branch block pattern in 10 patients and a right bundle branch block in one patient. A total of 18 dual-chamber and one single chamber pacemakers were implanted and a cardiac resynchronization therapy defibrillator (CRT-D) device. The acute pacing threshold was 0.56±0.2 V at 0.4ms, the sensing threshold was 10.3±3.9 mV and the impedance was 684.9±112.2 Ω. The overall QRS duration decreased after LBBAP from 128.5 ± 27ms to 103.6 ± 17.4ms (p= 0.001). In patients with baseline wide QRS complex there was a highly significant decrease from 148.2 ± 11.6 ms to 104.7 ± 19.4 ms (p<0.001). The fl uoroscopy time, including the time spent for His bundle location, was 13.8 ± 8.5 minutes. The pacing thresholds remained constant after three-months (0.6 ± 0.2 V vs. 0.56 ± 0.2 V at 0.4 ms). We had two intraprocedural septal perforations without any consequences and three micro dislodgements at follow-up with pure left septal capture. Conclusion: Left bundle branch area pacing is a feasible physiological pacing technique with a high success rate and the potential to overcome the limits of permanent His bundle pacing. It can be successfully performed virtually in all types of pacing indications, including cardiac resynchronization therapy as provides a rapid and synchronous activation of the left ventricle.

Keywords

• left bundle branch area
• cardiac pacing
• learning curve