Atrial fibrillation (AF) and heart failure (HF) are morbid, costly, and incompletely understood diseases that have reached epidemic proportions worldwide. A dose-dependent relationship exists between premature atrial and ventricular contractions (PACs and PVCs) and development of AF and HF, respectively. Identifying and understanding the mechanisms of additional modifiable risk factors for ectopy has the potential to markedly reduce the healthcare burden of these diseases. In considering how to modify the prevalence of these ectopic beats, the investigators believe common exposures in daily life are prime candidates. Current guidelines suggest that caffeine may be an important trigger for frequent ectopy, although large population-based studies have not demonstrated an association between caffeine consumption and development of clinically significant arrhythmias. No study has employed an actual randomization intervention to assess the effects of caffeine on cardiac ectopy. Utilizing the Eureka platform, the investigators plan to utilize the N-of-1 strategy to rigorously investigate the real-time effect of caffeine intake on ectopy.
For two weeks, participants will be asked to wear a continuously recording heart monitor and utilize the Eureka mobile application. On the Eureka app, participants will be able to track caffeine consumption and answer questions about mood and sleep. Participants will also receive their randomization assignment through Eureka. Participants will be asked to modify caffeine intake habits in two-day blocks; these assignments are either a) to consume caffeine for one day, then avoid caffeine the next day, or b) to avoid caffeine for one day, then consume caffeine the next day. Participants will also be given a wrist-worn fitness device (Fitbit), to track sleep, step counts, and heart rate data.