Cannabis linked to fewer short-term extra heartbeats in users

Inhaled cannabis is widely legal in the United States. Data regarding cardiovascular effects are conflicting and generally arise from observational studies. The goal was to evaluate the acute effects of cannabis inhalation on cardiac ectopy. We conducted a prospective, randomized, crossover trial to assess effects of inhaled cannabis on cardiac ectopy, mean glucose levels, step counts, and sleep durations. Adults who smoked or vaped cannabis on a regular basis without a history of cardiac arrhythmias were enrolled. Participants were randomly assigned each day to inhale vs abstain from cannabis via text messages for 14 days. Adherence was assessed using time-stamped Zio patch button presses at the time of cannabis use, daily surveys, and, in a subset, salivary mass spectrometry. The primary outcome was daily cardiac ectopy (daily premature atrial contractions and premature ventricular contractions). Of 108 participants (mean age 32 ± 10 years, 59% women, and 37% non-Hispanic White) experiencing a total of 713 days randomized to inhaled cannabis and 616 days randomized to abstinence, randomization adherence was imperfect but generally supportive of assignment adherence. 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. 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. Potential withdrawal effects, moderate adherence, and co-intervention limit interpretation of causal mechanism. (Marijuana and Acute Risk of Arrhythmia-Joint Abstinence and Exposure [MARY-JANE]; NCT06021613).