Echocardiographic response from left bundle branch area pacing optimized cardiac resynchronization therapy (LOT-CRT) vs traditional CRT.

BACKGROUND

Traditional cardiac resynchronization therapy (CRT) with biventricular pacing (BVP) may be less effective in patients with nonspecific intraventricular conduction delay (NIVCD). Left bundle branch area pacing (LBBAP) combined with left ventricular (LV) coronary venous lead pacing (LOT-CRT) may be more effective in these patients.

OBJECTIVE

We assessed the echocardiographic response of LOT-CRT in patients with left bundle branch block (LBBB) or NIVCD and compared it with a propensity-matched BVP cohort.

METHODS

Patients with conventional CRT indications and preferentially NIVCD were recruited. Echocardiographic parameters, including absolute percentage change in LV ejection fraction (LVEF) and relative percentage change in LV end-systolic volume (LVESV), were evaluated at implantation and 6-month follow-up. The BVP cohort was from an independent study, selected using 1:1 propensity-matching. LOT-CRT patients were subclassified into "successful LOT-CRT" (LBBAP; presence of r' in electrode electrocardiography [ECG] V1) and "deep septal optimized therapy" (DOT-CRT) (functional deep septal capture).

RESULTS

LOT-CRT patients (N = 34; age 64 years, women 38%, NIVCD 47%, LBBB 53%, implantable cardiac monitor 21%, QRSd 175 ms, and LVEF 27.6%) had significantly greater LVEF improvement (16.1% vs 6.1%; P <.01) and LVESV reduction (-43.5% vs -20.9%; P <.01) compared with BVP patients. After adjusting for baseline characteristics, LOT-CRT patients still had significantly greater LVEF improvement (7.5%; P <.01) and LVESV reduction (18.4%; P <.01) than BVP patients. The response was consistent across LBBB and NIVCD subgroups. LOT-CRT patients with QRS ≥ 171 ms showed greater benefit (P = .04; both LVEF and LVESV). No significant differences were observed between successful LOT-CRT and DOT-CRT.

CONCLUSION

LOT-CRT resulted in superior LVEF and LVESV improvements compared with BVP in NIVCD and LBBB patients and enhanced CRT response.