The effect of sex on ventricular arrhythmic events in patients with congestive heart failure.

The propensity to develop specific arrhythmias varies between the sexes. Patients with congestive heart failure (CHF) have a high prevalence of ventricular ectopy. However, it is not known if sex related differences exist in the susceptibility to arrhythmias in the setting of CHF. The study population included 159 men and 77 women (mean age 61 +/- 14 years) admitted for decompensated CHF. The severity of atrial and ventricular arrhythmias was assessed by 24-hour Holter monitoring. None of the patients were on parenteral vasoactive therapy during Holter recording. All measures of ventricular ectopy were markedly lower in women compared to men. The mean hourly ventricular pairs (283 +/- 67 vs 106 +/- 30, P = 0.04), mean hourly repetitive ventricular beats (28 +/- 7 vs 10 +/- 3, P = 0.04), and the frequency of ventricular tachycardia episodes per 24 hours (31 +/- 9 vs 7 +/- 3, P = 0.01) were significantly lower in women. After inclusion of clinical variables and drug therapies in a multivariate analysis, the negative relationship between female sex and the frequency of ventricular pairs (P = 0.04), repetitive ventricular beats (P = 0.04), and ventricular tachycardia episodes (P = 0.0005) remained independent. No differences in atrial ectopy between men and woman were found. Complex ventricular ectopy and episodes of ventricular tachycardia are significantly lower in women with CHF. Whether these finding are relevant to female survival advantage in the setting of heartfailure can only be determined by a prospective study. Further understanding of the mechanisms involved in the protection conferred by the patient's sex would advance our understanding about arrhythmias in heart failure.