SEX-DIFFERENCES IN CARDIAC-ARREST SURVIVORS

Background Important sex differences in the epidemiology of sudden dea th and in the results of electrophysiological testing in survivors of cardiac arrest have been identified. These differences are currently p oorly understood. Methods and Results Three hundred fifty-five consecu tive survivors of out-of-hospital cardiac arrest (84 women and 271 men ) referred for electrophysiologically guided therapy were analyzed ret rospectively for sex differences in underlying pathology and predictor s of outcome. Women were significantly less likely to have underlying coronary artery disease than men (45% versus 80%) and more likely to h ave other forms of heart disease or structurally normal hearts (P<.000 1). The mean left ventricular ejection fraction was higher in women (0 .46+/-0.18 versus 0.41+/-0.18, P<.05), and women were more likely to h ave no inducible arrhythmia at baseline electrophysiological testing ( 46% versus 27%, P=.002), although when the patients were stratified by coronary artery disease status, these sex differences were no longer present. The independent predictors of outcome differed between men an d women. In men, a left ventricular ejection fraction of <0.40 was the most powerful independent predictor of total (relative risk, 2.8; 95% CI, 1.6 to 5.0; P<.0001) and cardiac (relative risk, 6.3; 95% CI, 2.9 to 13.5; P<.0001) mortality. In contrast, the presence of coronary ar tery disease was the only independent predictor of total (relative ris k, 4.5; 95% CI, 1.5 to 13.4; P=.003) and cardiac (relative risk, 4.4; 95% CI, 1.2 to 15.6; P=.012) mortality in women. Conclusions Female su rvivors of cardiac arrest are less likely to have underlying coronary artery disease. The predictors of total and cardiac mortality differ b etween male and female survivors. Coronary artery disease status is th e most important predictor in women, and impaired left ventricular fun ction is the most important predictor in men.