A regular intake of up to 300 milligrams of coffee a day appears to be safe and may even protect the heart from rhythm disorders, including atrial fibrillation (AFib), according to a new review published April 16 in the Journal of the American College of Cardiology.
“Many clinicians continue to counsel patients with atrial or ventricular arrhythmias (VA) to avoid all caffeinated beverages, particularly coffee, despite an absence of evidence to support this approach,” wrote lead author Peter M. Kistler, MBBS, PhD, with the Baker IDI Heart and Diabetes Institute in Melbourne, Australia, and colleagues. “If, in individual cases where a clear temporal association between arrhythmia episodes and caffeine intake is apparent, then avoidance is sensible. Large-scale population-based studies and randomized controlled trials suggest coffee and tea are safe and may even reduce the incidence of arrhythmia.”
The researchers conducted a comprehensive review of published studies to better understand the link between coffee intake and arrhythmias. In a study in more than 228,000 patients, consumption of coffee cut the frequency of AFib by 6 percent. Another study with more than 115,000 patients saw a 13 percent reduction.
In a third study of more than 130,000 people, only 2.4 percent of patients were hospitalized for arrhythmia during a 17-year follow-up.
The researchers also noted that caffeine does not increase the likelihood of ventricular arrhythmias. A study of 22 patients with a history of ventricular arrhythmias who underwent electrophysiological study before and one hour after coffee consumption had no significant difference in inducibility of ventricular arrhythmias.
In five placebo-controlled trials, consumption of 500 mg, or six cups of coffee, did not increase the frequency of ventricular arrhythmias. In a study of 103 patients with post-myocardial infarction, regular caffeine consumption improved heart rate variability, increased parasympathetic activity and did not produce significant arrhythmias compared to the control group.
Of eight studies involving more than 232,000 patients, six studies demonstrated no association between coffee consumption and ventricular arrhythmias. Two older studies did demonstrate an association between coffee consumption and ventricular arrhythmias—but the levels of intake were more than nine cups per day.
The researchers did note patients with heart conditions should avoid caffeinated drinks. Their research showed about 75 percent of patients with heart conditions who drank two or more energy drinks in a day had palpitations within 24 hours of consumption.
As a senior news writer for TriMed, Subrata covers cardiology, clinical innovation and healthcare business. She has a master’s degree in communication management and 12 years of experience in journalism and public relations.