A team of researchers based in the United States and affiliated with the Division of Cardiology in the Department of Medicine at the University of California conducted a randomized crossover trial to learn more about inhaled cannabis use and its impact on cardiovascular health. What they found was surprising.

“Inhaled cannabis is widely legal in the United States. Data regarding cardiovascular effects are conflicting and generally arise from observational studies.” the researchers wrote. “The goal was to evaluate the acute effects of cannabis inhalation on cardiac ectopy.”

Cardiac ectopy refers to an extra or early heartbeat that is irregular compared to a person’s normal regular heartbeat rhythm. The word ‘ectopic’ is derived from the Greek language, meaning “out of place.” Most of the time, ectopic heartbeats are harmless. However, if they are coupled with other issues, such as shortness of breath or chest pain, or if they are happening frequently, it could be indicative of a bigger issue that warrants going to see a doctor.

The randomized crossover trial conducted by researchers affiliated with the University of California involved 108 participants. The subjects were all self-reported cannabis consumers who smoked or vaped cannabis and did not have a history of cardiac arrhythmias. Participants were randomly assigned daily to either inhale cannabis or abstain over 14 days. The researchers’ findings were published in the Journal of the American College of Cardiology.

“Inhaled cannabis resulted in a statistically significant 9% reduction in ectopic beats (rate ratio [RR]: 0.91; 95% CI: 0.85-0.98; P = 0.02). Daily premature atrial contractions decreased by 10% (RR: 0.90; 95% CI: 0.82-0.97; P = 0.012), whereas premature ventricular contractions showed no significant change. Each cannabis inhalation was associated with a 2% reduction in ectopic beats (RR: 0.98; 95% CI: 0.97-0.99; P = 0.043). No significant differences were observed for step counts, sleep duration, or glucose levels.” the researchers found.

“In a pragmatic crossover design including habitual cannabis users, randomization to inhaled cannabis was associated with less cardiac ectopy, driven by fewer premature atrial contractions.” the researchers concluded.