CRT in patients with complete LBBB without residual conduction yielded greater LVEF improvement compared to those with residual conduction (11.9% vs 3.8%, P=0.045).
Cohort (n=40)
Does the absence of ECG markers of residual left bundle conduction predict a greater response to cardiac resynchronization therapy in patients with guideline-defined LBBB?
The absence of ECG markers of residual left bundle conduction (true complete LBBB) predicts a significantly greater improvement in left ventricular function following cardiac resynchronization therapy.
Tasa de eventos absoluta: 11.9% vs 3.8%
valor p: p=0.045
AIMS: Cardiac resynchronization therapy (CRT) benefits patients with heart failure and a wide QRS complex. Still, one-third derive no clinical benefit and a majority of patients demonstrate no objective improvement of left ventricular (LV) function. Left bundle branch block (LBBB) is a strong predictor of response to CRT. We evaluated whether absence of electrocardiogram (ECG) markers of residual left bundle (LB) conduction in guideline-defined LBBB predicted a greater response to CRT. METHODS AND RESULTS: An r wave ≥1 mm in lead V1 (r-V1) and/or a q wave ≥1 mm in lead aVL (q-aVL) was used to identify patients with residual LB conduction. Forty patients with a wide QRS were prospectively enrolled and subdivided into three groups: complete LBBB (cLBBB), LBBB without r-V1 or q-aVL (n = 12); LBBB with residual LB conduction (rLBBB), LBBB with r-V1 and/or q-aVL (n = 15); and non-specific intraventricular conduction delay (IVCD), (n = 13). Following CRT: mean change in left ventricular ejection fraction was 11.9 ± 11.9% in cLBBB, 3.8 ± 5.4% in rLBBB (P= 0.045), and 2.5 ± 4.4% in IVCD (P= 0.02 cLBBB vs. IVCD); mean reduction in left ventricular end-systolic volume was 26.4 ± 39.2% in cLBBB, 14.3 ± 22.9% in rLBBB (P= 0.35), and 5.6 ± 17.3% in IVCD (P= 0.11 cLBBB vs. IVCD); mean change in native QRS duration was -8.0 ± 11.0 ms in cLBBB, -0.8 ± 8.24 ms in rLBBB (P= 0.07), and 0.15 ± 8.0 ms in IVCD (P= 0.048 cLBBB vs. IVCD). CONCLUSION: In patients with guideline-defined LBBB, the absence of ECG markers of residual LB conduction was predictive of a greater improvement in LV function with CRT.
Perrin et al. (Wed,) conducted a cohort in Heart failure with wide QRS complex (n=40). Cardiac resynchronization therapy (CRT) in complete LBBB vs. CRT in LBBB with residual conduction or IVCD was evaluated on Mean change in left ventricular ejection fraction (p=0.045). CRT in patients with complete LBBB without residual conduction yielded greater LVEF improvement compared to those with residual conduction (11.9% vs 3.8%, P=0.045).