Left ventricular regional contraction abnormalities by echocardiographic speckle tracking in combined right bundle branch with left anterior fascicular block compared to left bundle branch block

Background: In contrast to LBBB patients less is known about patients with RBBB + LAFB regarding LV contractile abnormalities and the potential role of CRT. This study investigated whether patients with RBBB + LAFB morphology have echocardiographic mechanical strain abnormalities between the inferior and anterior LV walls, similar to abnormalities between septal and lateral walls in LBBB. Methods and results: Ten healthy volunteers with no-BBB, 28 LBBB and 28 RBBB + LAFB heart failure patients were included in this retrospective study. Two-dimensional regional-strains were obtained by speckle-tracking. Scar was assessed by CMR. Response on echo was defined as normal, classical, borderline or other pattern. The number of classical patterns in LBBB was significantly higher than in RBBB + LAFB and no-BBB groups (p <0.001 for both). Contrary, the RBBB + LAFB group showed a significantly higher number of borderline patterns compared to other groups (LBBB: p = 0.042, no-block: p = 0.012). In addition, RBBB + LAFB patients had more scar than LBBB patients (9.9% vs 3.4%, p = 0.041), and the average amount of scar in each wall was also higher in RBBB + LAFB (