Association of QRS Notch Resolution During LV-Only Fusion Pacing With Early Left Ventricular Reverse Remodeling After Cardiac Resynchronization Therapy.

BACKGROUND

Cardiac resynchronization therapy (CRT) improves outcomes in patients with heart failure and left bundle branch block (LBBB); however, many patients remain non-responders. Identifying effective electrical resynchronization early remains an important clinical need.

OBJECTIVE

To investigate the association between resolution of V5-V6 R-wave notching/slurring during left ventricular-only pacing (LV-only pacing), combined with an LV-only pacing percentage ≥ 50% at 1 month, and early left ventricular reverse remodeling in patients with complete LBBB (CLBBB) undergoing CRT.

METHODS

We retrospectively studied 49 patients with CLBBB who underwent CRT. Patients with resolution of V5-V6 R-wave notching/slurring during LV-only pacing at implantation and an LV-only pacing percentage ≥ 50% at 1 month were classified as the R-Notch Resolution group; all others were classified as the Non-R-Notch Resolution group. The primary endpoint was left ventricular reverse remodeling at 1 month, defined as a ≥ 15% reduction in left ventricular end-systolic volume (LVESV) from baseline. Logistic regression analysis was performed to identify associated factors.

RESULTS

Fifteen patients were classified into the R-Notch Resolution group and 34 into the Non-R-Notch Resolution group. One-month left ventricular reverse remodeling occurred more frequently in the R-Notch Resolution group (80.0% vs. 47.1%). In multivariable logistic regression analysis, R-Notch Resolution group status remained independently associated with 1-month left ventricular reverse remodeling.

CONCLUSION

Resolution of V5-V6 R-wave notching/slurring during LV-only pacing, combined with an LV-only pacing percentage ≥ 50% at 1 month, was independently associated with early left ventricular reverse remodeling after CRT.