Sex Differences in Left Ventricular Electrical Dyssynchrony and Outcomes with Cardiac Resynchronization Therapy

ABSTRACT Background Women appear to derive more benefit from cardiac resynchronization therapy(CRT) than men, even after accounting for the higher burden of risk factors for non-response often observed in men. Objective To assess for sex-specific differences in left ventricular(LV) electrical dyssynchrony as a contributing electrophysiological explanation for the greater degree of CRT benefit among women. Methods We compared the extent of baseline LV electrical dyssynchrony, as measured by the QRS area(QRSA), among men and women with LBBB undergoing CRT at Duke University(n=492, 35% women) overall and in relation to baseline QRS characteristics using independent sample t-tests and Pearson’s correlation coefficients. Cox regression analyses were used to relate sex, QRSA, and QRS characteristics, to the risk of cardiac transplantation, LV assist device implant, or death. Results Although the mean QRS duration(QRSd) did not differ by sex, QRSA was greater for women versus men(113.8μVs vs. 98.2μVs, p Conclusions Our study suggests that sex-specific differences in LV dyssynchrony contribute to greater CRT benefit among women. Standard QRSd and morphology assessments appear to underestimate the extent of LV electrical dyssynchrony among women with LBBB.