Sex‐specific clinical outcomes after cardiac resynchronization therapy in left bundle branch block‐associated idiopathic nonischemic cardiomyopathy: A NEOLITH II substudy

Abstract

Background: Sex differences in clinical outcomes for left bundle branch block (LBBB)associated idiopathic nonischemic cardiomyopathy (NICM) after cardiac resynchronization therapy (CRT) are not well described. Methods: A retrospective cohort study at an academic medical center included subjects with LBBB-associated idiopathic NICM who received CRT. Cox regression analyses estimated the hazard ratios (HRs) between sex and clinical outcomes. Results: In 123 total subjects (mean age 62 years, mean initial left ventricular ejection fraction 22.8%, 76% New York Heart Association class III, and 98% CRT-defibrillators), 55 (45%) were men and 68 (55%) were women. The median follow-up time after CRT was 72.4 months. Similar risk for adverse clinical events (heart failure hospitalization, appropriate implantable cardioverter-defibrillator shock, appropriate antitachycardia pacing therapy, ventricular assist device implantation, heart transplantation, and death) was observed between men and women (HR, 1.20; 95% confidence interval [CI] 0.57-2.51; p = 0.63). This persisted in multivariable analyses. Men and women had similar risk for all-cause mortality in univariable analysis, but men had higher risk in the final multivariable model that adjusted for age at diagnosis, QRS duration, and left ventricular end-diastolic dimension index (HR, 4.55; 95% CI, 1.26-16.39; p = 0.02). The estimated 5-year mortality was 9.5% for men and 6.9% for women. Conclusions: In LBBB-associated idiopathic NICM, men have higher risk for all-cause mortality after CRT when compared to women. K E Y W O R D S cardiac resynchronization therapy, clinical outcomes, left bundle branch block, nonischemic cardiomyopathy, sex-specific How to cite this article: Wang NC, Mezu-Chukwu U, Adelstein EC, et al. Sex-specific clinical outcomes after cardiac resynchronization therapy in left bundle branch block-associated idiopathic nonischemic cardiomyopathy: A

The Canadian Women’s Heart Health Alliance Atlas on the Epidemiology, Diagnosis, and Management of Cardiovascular Disease in Women — Chapter 6: Sex- and Gender-Specific Diagnosis and Treatment

“…CRT-D may confer greater benefits to women than to men in the setting of NICM and LBBB. 175 , 176 , 177 , 178 Subgroup analysis of the M ulticenter A utomatic D efibrillator I mplantation T rial With C ardiac R esynchronization T herapy (MADIT-CRT) study identified women as exceptional responders to CRT, with a 72% decrease in all-cause mortality and greater reduction in left atrial and ventricular volumes. 178 Despite men typically being younger at diagnosis, in a retrospective study conducted by Wang et al., women were found to have a lower risk of death, compared with men in LBBB-associated NICM, after controlling for age at diagnosis.…”

“…178 Despite men typically being younger at diagnosis, in a retrospective study conducted by Wang et al., women were found to have a lower risk of death, compared with men in LBBB-associated NICM, after controlling for age at diagnosis. 176 Women have a shorter baseline QRS duration (QRSd) and smaller LV volumes than men. Therefore, women have relatively more dysynchrony for any prolonged QRSd, which may contribute to a better outcome with CRT.…”