Anne B. Curtis

Frequency of Symptomatic Atrial Fibrillation in Patients Enrolled in the Atrial Fibrillation Follow‐up Investigation of Rhythm Management (AFFIRM) Study

AF Frequency. Introduction: The frequency of symptomatic paroxysmal atrial fibrillation (AF) may identify subsets with different characteristics. Because the approach to AF now is so varied, ranging from drug therapy to surgery and catheter ablation, the frequency of AF may have important therapeutic implications if the frequency identifies subsets with distinguishing features.

Prevention of sudden cardiac death: when is a woman just like a man?

Cardiovascular disease is the leading cause of death in both men and women, with sudden cardiac death (SCD) accounting for approximately half the total mortality.1 Strategies to prevent SCD are critical in order to improve overall survival. The implantable cardioverter defibrillator (ICD) has become the mainstay of therapy in this area because of its extremely high efficacy in terminating potentially lethal ventricular arrhythmias. Although it is clear that SCD is a significant public health problem, there are known differences in the epidemiology of SCD in men and women that may impact strategies for risk stratification and prevention. Women have a lower incidence of SCD compared to men, and their event rates lag 10 to 20 years behind those in men. In the Framingham study, only 37% of women who had SCD had a history of coronary heart disease, whereas 56% of the men had such a history.2 With only a minority of women having an overt history of cardiac disease prior to SCD, risk stratification and primary prevention become difficult undertakings. In addition, among patients with known coronary heart disease, women have one fourth the risk of SCD found in men. Of the total mortality due to coronary heart disease in the Framingham study, half of the deaths in men were SCD compared to only one fourth in women.2 In the Nurses’ Health Study, 28% to 35% of all cardiac deaths were due to SCD, and although the risk of SCD increased with advancing age, the percentage of all cardiac deaths that were sudden actually decreased.3 The reasons for the lower incidence of SCD in women are not known. Hormonal influences are a possibility, but the mechanisms certainly are not clear. Clinical trials of ICD therapy have rightly focused for the most part on total mortality as an endpoint. However, ICDs can only prevent death due to arrhythmias; thus, their impact on mortality will necessarily be due to a reduction in SCD. The validity of this statement was confirmed recently by an analysis of mode of death in the Multicenter Automatic Defibrillator Implantation Trial (MADIT) II trial, in which the reduction in total mortality was almost entirely explained by a reduction in SCD.4 With women having a lower incidence of SCD than men in the setting of coronary artery disease, the potential value of ICD therapy in women for improving survival could be less as well, which is interesting, potentially problematic, and clearly worth exploring.