Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease (Jun 2024)

Heart Size Difference Drives Sex‐Specific Response to Cardiac Resynchronization Therapy: A Post Hoc Analysis of the MORE‐MPP CRT Trial

  • Nadeev Wijesuriya,
  • Vishal Mehta,
  • Felicity De Vere,
  • Sandra Howell,
  • Steven A. Niederer,
  • Haran Burri,
  • Johannes Sperzel,
  • Leonardo Calo,
  • Bernard Thibault,
  • Wenjiao Lin,
  • Kwangdeok Lee,
  • Andrea Grammatico,
  • Niraj Varma,
  • Marianne Gwechenberger,
  • Christophe Leclercq,
  • Christopher A. Rinaldi

DOI
https://doi.org/10.1161/JAHA.123.035279
Journal volume & issue
Vol. 13, no. 12

Abstract

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Background Studies have reported that female sex predicts superior cardiac resynchronization therapy (CRT) response. One theory is that this association is related to smaller female heart size, thus increased relative dyssynchrony at a given QRS duration (QRSd). Our objective was to investigate the mechanisms of sex‐specific CRT response relating to heart size, relative dyssynchrony, cardiomyopathy type, QRS morphology, and other patient characteristics. Methods and Results This is a post hoc analysis of the MORE‐CRT MPP (More Response on Cardiac Resynchronization Therapy with Multipoint Pacing) trial (n=3739, 28% women), with a subgroup analysis of patients with nonischemic cardiomyopathy and left bundle‐branch block (n=1308, 41% women) to control for confounding characteristics. A multivariable analysis examined predictors of response to 6 months of conventional CRT, including sex and relative dyssynchrony, measured by QRSd/left ventricular end‐diastolic volume (LVEDV). Women had a higher CRT response rate than men (70.1% versus 56.8%, P<0.0001). In subgroup analysis, regression analysis of the nonischemic cardiomyopathy left bundle‐branch block subgroup identified QRSd/LVEDV, but not sex, as a modifier of CRT response (P<0.0039). QRSd/LVEDV was significantly higher in women (0.919) versus men (0.708, P<0.001). CRT response was 78% for female patients with QRSd/LVEDV greater than the median value, compared with 68% with QRSd/LVEDV less than the median value (P=0.012). The association between CRT response and QRSd/LVEDV was strongest at QRSd <150 ms. Conclusions In the nonischemic cardiomyopathy left bundle‐branch block population, increased relative dyssynchrony in women, who have smaller heart sizes than their male counterparts, is a driver of sex‐specific CRT response, particularly at QRSd <150 ms. Women may benefit from CRT at a QRSd <130 ms, opening the debate on whether sex‐specific QRSd cutoffs or QRS/LVEDV measurement should be incorporated into clinical guidelines.

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