Left bundle branch area pacing delivery of cardiac resynchronization therapy and comparison with biventricular pacing

Abstract

Aims: This multicentre observational study aimed to prospectively assess the efficacy of left bundle branch area pacing (LBBAP) in heart failure patients with left bundle branch block (LBBB) and compare the 6-month outcomes between LBBAP and biventricular pacing (BVP).

Methods and results: Consecutive patients with LBBB and left ventricular ejection fraction (LVEF) ≤ 35% were prospectively recruited if they had undergone LBBAP as a primary or rescue strategy from three separate centres from March to December 2018. Patients who received BVP in 2018 were retrospectively selected by using 2 to 1 propensity score matching to minimize bias. Implant characteristics and echocardiographic parameters were assessed during the 6-month follow-up. LBBAP procedure succeeded in 81.1% (30/37) of patients, with selective LBBAP in 10 patients, and 3 of 20 patients combined non-selective LBBAP and LV lead pacing for further QRS narrowing. LBBAP resulted in significant QRS narrowing (from 178.2 ± 18.8 to 121.8 ± 10.8 ms, P < 0.001, paced QRS duration ≤ 130 ms in 27 patients) and improved LVEF (from 28.8 ± 4.5% to 44.3 ± 8.7%, P < 0.001) during the 6-month follow-up. The comparison between 27 patients with LBBAP alone and 54 of 130 matching patients with BVP showed that LBBAP delivered a greater reduction in the QRSd (58.0 vs. 12.5 ms, P < 0.001), a greater increase in LVEF (15.6% vs. 7.0%, P < 0.001), and greater echocardiographic (88.9% vs. 66.7%, P = 0.035) and super response (44.4% vs. 16.7%, P = 0.007) to cardiac resynchronization therapy.

Conclusions: LBBAP could deliver cardiac resynchronization therapy in most patients with heart failure and LBBB, and might be a promising alternative resynchronization approach to BVP.

Keywords: Cardiac resynchronization therapy; Heart failure; Left bundle branch area pacing; Left bundle branch block.

Figure 1

Schematic diagram of the lead‐to‐device connection configurations. CRT‐D: cardiac resynchronization therapy defibrillator; CRT‐P: cardiac resynchronization therapy pacemaker.

Figure 2

Pacing electrocardiogram characteristics and the location of the pacing lead for left bundle branch area pacing. Intrinsic rhythm of LBBB (A); LVAT remains stable for different pacing outputs (B and C); The transition from NS‐LBBP to S‐LBBP (discrete component in the intracardiac EGM, red arrow, D). The location of the LBB pacing lead on CT scan and 3D echocardiogram (E and F). LBB pacing with intrinsic RBB conduction. When the SAV was 110 ms, the best QRS morphology and duration were achieved (F). LBBB, left bundle branch block; LVAT, left ventricular activation time; NS‐LBBP, non‐selective left bundle branch pacing; S‐LBBP, selective left bundle branch pacing; EGM, electrogram; CT, computed tomography; LBB, left bundle branch; RBB, right bundle branch.

Figure 3

QRS duration and cardiac function at baseline and at the 6‐month follow up in LBBAP patients. Intrinsic QRS duration at baseline, narrowed QRS duration by LBBAP at implant, and final paced QRS duration at 6‐month follow‐up (A). NYHA functional class and left ventricular ejection fraction improvement from baseline to the 6‐month follow‐up (B to C). Left ventricular end‐diastolic diameter changes from baseline to the 6‐month follow‐up (D). NYHA, New York Heart Association.

Figure 4

Comparison of changes in QRS duration and cardiac functional parameters from baseline to 6 months after the procedure between BVP and LBBAP. (A) Reduction in QRS duration; (B) improvement in LVEF; (C and D) reduction in LVEDD and median improvement in NT‐proBNP level. LVEF, left ventricular ejection fraction; LVEDD, left ventricular end‐diastolic diameter.