Underrepresentation of women in implantable cardioverter defibrillator trials

There are sex differences in the epidemiology and presentation of ventricular arrhythmias. Sudden cardiac death (SCD) is less common in women than in men. Women have been under-represented in implantable cardioverter defibrillator (ICD) trials evaluating the benefit of ICD therapy for primary and secondary prevention of SCD. Following ICD implantation, women are less likely to experience appropriate ICD therapy for ventricular arrhythmias, consistent with epidemiological findings of a lower rate of SCD in women. Sex differences in ICD implantation rates have also been noted for primary and secondary prevention of SCD in registries and large observational cohort studies. Reasons for these differences are unclear. Age and comorbidities at the time of presentation may be partially responsible, although sex bias, patient preference, or contribution of social determinants of health cannot be excluded. There are many unanswered questions regarding reasons for sex differences in ICD usage and under-representation of women in clinical device trials. Additional investigation is needed to better understand these differences to improve outcome of all patients who are at risk for sudden cardiac arrest.