Don't expect left ventricular reverse remodeling after cardiac resynchronization therapy in patients with systolic heart failure and atrioventricular block: A multicenter study

Abstract Background The BLOCK HF trial showed that heart failure patients with atrioventricular block (AVB) and left ventricular systolic dysfunction (LVSD) are considered good candidates for cardiac resynchronization therapy (CRT), even though they have a narrow QRS duration. We aimed to compare the clinical response to CRT between patients with AVB combined with LVSD and patients with pre-existing CRT indications. Methods We compared the clinical data on CRT across the following 3 groups in 3 cardiovascular centers; heart failure patients with an LV ejection fraction (LVEF) of ≤35% who had a QRS duration of ≥120ms (standard indication, n=125), those needing an upgrade to CRT (upgrade, n=49), and patients with an LVEF of ≤50% who had advanced AVB (AVB with LVSD, n=27). Results The prevalence of left bundle branch block differed significantly across the groups (87.2%, 98.0% and 40.7%; P Conclusions As compared to patients with preexisting CRT indications, CRT may be similarly effective for patients with AVB and LVSD, however, LV reverse remodeling may be uncommon among them.