Resynchronization effects and clinical outcomes during left bundle branch area pacing with and without conduction system capture

Background Left bundle branch area pacing (LBBAP) includes left bundle branch pacing (LBBP) and left ventricular (LV) septal myocardial pacing (LVSP). Hypothesis The study aimed to assess resynchronization effects and clinical outcomes by LBBAP in heart failure (HF) patients with cardiac resynchronization therapy (CRT) indications. Methods LBBAP was successfully performed in 29 consecutive patients and further classified as the LBBP‐group (N = 15) and LVSP‐group (N = 14) based on the LBBP criteria and novel LV conduction time measurement (LV CT, between LBBAP site and LV pacing (LVP) site). AV‐interval optimized LBBP or LVSP, or LVSP combined with LVP (LVSP‐LVP) was applied. LV electrical and mechanical synchrony and clinical outcomes were assessed. Results All 15 patients in the LBBP‐group received optimized LBBP while 14 patients in the LVSP‐group received either optimized LVSP (5) or LVSP‐LVP (9). The LV CT during LBBP was significantly faster than that during LVP (p