Cardiac MRI scar patterns differ by sex in an implantable cardioverter-defibrillator and cardiac resynchronization therapy cohort.

BACKGROUND

Recent meta-analyses suggest that the effectiveness of cardiac devices may differ between genders. Compared to men, women may not benefit as much from implantable cardioverter-defibrillators (ICDs), yet benefit more from cardiac resynchronization therapy (CRT). Myocardial scar burden is associated with increased incidence of appropriate ICD shocks but decreased response to CRT and may explain gender differences in device benefit.

OBJECTIVE

To test the hypothesis that the extent of myocardial scar is less in women than men.

METHODS

In 235 patients referred for primary prevention ICDs who underwent cardiac magnetic resonance imaging, we compared scar size by gender. Analyses were performed for all patients (ICD cohort) and those receiving biventricular pacemakers (CRT subgroup).

RESULTS

In the ICD cohort, women (vs men) had a higher prevalence of nonischemic cardiomyopathy (NICM; 64% vs 39%; P<.001), which accounted for a smaller overall scar burden (0.5% vs 13%, P<.01). Likewise, in the CRT subgroup, the higher prevalence of NICM in women (83% vs 46%; P = .01) also contributed to a smaller scar size (0% vs 13%; P<.01). Women also had significantly less scarring of the inferolateral left ventricular wall.

CONCLUSIONS

In a cohort of patients undergoing clinically indicated ICD and CRT, women had less myocardial scar than did men. This difference was primarily driven by a higher prevalence of NICM in women. These findings may have important implications for the future study of gender disparities in ICD and CRT outcomes.