Gender differences in cardiac remodeling secondary to chronic volume overload

Background: Gender differences in the prevalence of cardiovascular disease, both clinical and experimental, led us to evaluate the influence of gender on ventricular remodeling induced by chronic volume overload. Methods and Results: Chronic volume overload was induced in male and female rats via infrarenal aortocaval fistula. Ventricular function was assessed 8 weeks after fistula surgery in surviving rats. Left ventricular, right ventricular, and lung weights were measured. Mortality in female rats was 10-fold less than in male rats after 8 weeks of volume overload. Both sexes had significant increases in left ventricular weights relative to controls (77% increase for female nu 114% for male rats; P < .05). Corresponding increases were also observed in right ventricular weight (134% for female nu 161% for male rats; P < .05). However, lung weight was significantly increased only in males. In contrast to males, female rats had no indications of congestive heart failure. Male rats had marked dilatation and increased compliance, whereas female rats had no significant change in left ventricular dilatation or compliance. Conclusions: There are clear gender-specific differences in ventricular function, structural remodeling, and mortality induced by chronic volume overload in this model of heart failure.