The WHI Strong and Healthy SilenT Atrial febrillation Recording study (WHISH STAR)

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and confers significant risk of morbidity and mortality. There are approximately 2.2 million people in the US with AF1, which accounts for up to 100,000 strokes per year2 and is associated with increased mortality.3 AF is also linked to congestive heart failure, myocardial infarction4 , sudden cardiac death5 and dementia. Women comprise 60% of individuals with AF over the age of 75,6 are more likely than men to develop stroke and MI, and have a higher mortality risk than men with AF.2, 3, 7 Current AF treatments are limited and novel preventive strategies are needed. Lifestyle weight loss intervention, which includes low intensity exercise, can reduce AF episodes8. We found that moderate degrees of physical activity (PA) were associated with a reduction in incident AF in the Women’s Health Initiative (WHI)9. Others report higher rates of AF after high endurance exercise10-16. A challenge for interventions to reduce AF is that many AF events are thought to be asymptomatic and undetected. The significance of asymptomatic AF is not clear, but in patients with cryptogenic stroke, 12.2% of patients have silent AF found on implantable monitors17. Wearable patch monitors are used to screen for AF with high compliance18, however, the prevalence of silent AF and efficacy of subsequent interventions are not known. Our long term goal is to reduce rates of AF with safe and appropriate lifestyle recommendations. The WHI Strong & Healthy (WHISH) trial is an NIH-funded study where women will be randomized to receive exercise instructions via mailings and an interactive voice response system and followed for subsequent cardiovascular outcomes. We propose this ancillary study, WHISH STAR (Figure 1), designed to study the effects of PA on atrial fibrillation. Our overall hypothesis is that physical activity intervention reduces rates of clinical and silent AF. AF and risk factors were measured at baseline WHI