Coffee does not increase the risk of arrhythmias
The Coffee and Real-time Atrial and Ventricular Ectopy (CRAVE) presented at the American Heart Association (AHA) Scientific Sessions on 14th November 2021.
Is coffee drinking OK? Some cardiologists and even professional societies warn against caffeine consumption in patients with palpitations and arrhythmias. However, the recommendations are mostly based on observational studies and there is some conflicting evidence that coffee can actually reduce the risk of arrhythmias, and diabetes. In an observational survey in 10 European countries, published in the Annals of Internal Medicine in 2017, coffee drinking was even associated with a reduced risk of death.
According to the CRAVE trial, presented on 14th November 2021 at the American Heart Association (AHA) Scientific Sessions, drinking coffee does increase the frequency of ventricular ectopics but not atrial arrhythmias. Coffee consumption was also linked to increased physical activity and reduction in sleep duration. In the trial, 200 healthy volunteers with an average age of 38 years alternated days with unlimited coffee consumption with days with no coffee. They used a smartphone app to record every coffee they had. The volunteers wore an ECG monitor and Fitbit which counted their steps and sleep duration.
Data collected over a median of 13 days showed a daily average of 13 atrial/supraventricular ectopic beats (SVEs), 8 ventricular ectopics (VEs), one episode of supraventricular tachycardia (SVT) and one non-sustained ventricular tachycardia (NSVT). Coffee consumption did not increase the number of SVEs (RR, 1.09; 95% CI, 0.98 - 1.20; P = 0.10) but it did increase the number of VEs (RR, 1.54; 95% CI, 1.19 - 2.00; P = 0.001). There was no effect of caffeine intake on the number of SVT or NSVT episodes. Coffee drinking was associated with more physical activity compared with days without coffee (95% CI, 441 - 1675 steps; P = 0.001) and shorted sleep (95% CI, 22 - 50 minutes; P < 0.001).
Coffee is enjoyed by millions of people and even a small negative health effect would be therefore highly significant. No effect on atrial ectopics is in keeping with previous trials. For patients with ventricular ectopics, it makes sense to try and reduce coffee intake for a few days to see if it makes any difference. The purported increased frequency of VEs in this trial however contradicts some previous findings, including a randomized trial published in JAMA Internal Medicine in 2016 which did not find any increase in VE frequency in patients with heart failure and left ventricular ejection fraction <45%. These were patients with much higher baseline cardiovascular risk than young healthy volunteers in CRAVE study; if caffeine was safe in them, a mild increase in VEs in low-risk patients would appear clinically insignificant.
My conclusion from this trial is that coffee is safe and apart from symptomatic patients with palpitations, frequent VEs on ECG monitor and high caffeine intake, there is no need for abstinence. Better to concentrate on stuff that matters; the big one in arrhythmias, and particularly atrial fibrillation, is undoubtedly alcohol.