Sex-Specific Response to Cardiac?Resynchronization Therapy

摘要

Abstract Objectives In this study, the authors sought to assess the impact of body and heart size on sex-specific cardiac resynchronization therapy (CRT) response rate, according to QRS duration (QRSd) as a continuum. Background Effects of CRT differ between sexes for any given QRSd. Methods New York Heart Association functional class III/IV patients with nonischemic cardiomyopathy and “true” left bundle branch block (LBBB) were evaluated. Left ventricular mass (LVM) and end-diastolic volume were measured echocardiographically. Positive response was defined by left ventricular ejection fraction (LVEF) improvement post-CRT. Results Among 130 patients (LVEF 19 ± 7.1%; QRSd 165 ± 20 ms; 55% female), CRT improved LVEF to 32 ± 14%?(p??0.001) during a median 2 years follow-up. Positive responses occurred in 103 of 130 (79%) (78% when QRSd?150?ms vs. 80% when QRSd?≥150 ms; p?= 0.8). Body surface area (BSA), QRSd, and LVM were lower in women, but QRSd/LVM ratio greater (p? 0.0001). Sexes did not differ for pharmacotherapy and comorbidities, but female CRT?response was greater: 90% (65 of 72) versus 66% (38 of 58) in males (p? 0.001). With QRSd as a continuum, the overall CRT–response relationship showed a progressive increase to plateau between 150 and 170 ms, then a decrease. Sex-specific differences were conspicuous: among females, a peak effect was observed between 135 and 150 ms, thereafter a decline, with the male response rate lower, but with a gradual increase as QRSd lengthened. Sex-specific differences were unaltered by BSA, but resolved with integration of LVM or end-diastolic volume. Conclusions Sex differences in the QRSd–response relationship among CRT patients with LBBB were unexplained?by?application of strict LBBB criteria or by BSA, but resolved by QRSd normalization for heart size using LV mass or volume. Graphical abstract Display Omitted