Short-Term Caffeine Use Isn't Associated with Arrhythmias in Heart Failure Patients

Caffeine is believed to increase risk for ventricular and atrial arrhythmias, especially in patients with cardiac disease, but data to support this concern are sparse and mostly observational. In this crossover trial from Brazil, researchers examined the effects of high-dose, short-term caffeine consumption in 51 adults (mean age, 61) with heart failure and moderate-to-severe left ventricular systolic dysfunction (mean ejection fraction, 29%); 61% of participants had implantable cardioverter-defibrillator devices. After a 7-day caffeine-abstinent washout, participants were randomized to receive 100 mL of decaffeinated coffee plus either 100 mg of caffeine (the amount in a typical cup of coffee) or placebo hourly for 5 hours, followed by tre…