Randomized Clinical Trial Finds Inhaled Marijuana Associated With Fewer Irregular Heartbeats
- The randomized clinical trial found that inhaling marijuana led to a modest but statistically significant 9% reduction in irregular heartbeats (cardiac ectopy) among regular cannabis users, mainly driven by a 10% decrease in premature atrial contractions (PACs).
- The study involved 108 adults who regularly smoked or vaped marijuana and had no history of cardiac arrhythmias; participants alternated daily between cannabis inhalation and abstinence over 14 days while wearing cardiac monitoring patches.
- No significant changes were observed between cannabis use and abstinence days in terms of premature ventricular contractions (PVCs), daily step counts, sleep duration, or average glucose levels.
- Researchers cautioned that the results do not prove protective effects of cannabis on heart rhythm due to imperfect adherence and potential confounding factors, but the findings offer controlled data beyond previous observational studies on marijuana's cardiovascular impacts.
Inhaling marijuana was associated with a modest but statistically significant reduction in certain irregular heartbeats among regular cannabis users, according to a new randomized clinical trial.
The study, published in the Journal of the American College of Cardiology, involved researchers from the University of California and examined the acute cardiovascular effects of inhaled cannabis.
Researchers enrolled 108 adults who regularly smoked or vaped marijuana and had no history of cardiac arrhythmias. Over a 14-day period, participants were randomly instructed each day to either inhale cannabis or abstain.
Participants wore Zio cardiac monitoring patches, allowing researchers to track premature atrial contractions (PACs) and premature ventricular contractions (PVCs), collectively known as cardiac ectopy.
Across 713 days assigned to cannabis use and 616 days assigned to abstinence, inhaled marijuana was associated with a 9% reduction in ectopic beats compared with abstinence.
The difference was primarily driven by PACs, which were 10% lower on cannabis-use days. Researchers found no statistically significant change in PVCs.
The study also found that each reported episode of cannabis inhalation was associated with a 2% reduction in ectopic beats.
No significant differences were observed between cannabis and abstinence days for daily step counts, sleep duration or average glucose levels.
The findings are notable given that previous research examining marijuana and cardiovascular health has largely relied on observational data, which can make it difficult to determine whether cannabis itself is responsible for an observed effect.
Researchers cautioned against interpreting the results as evidence that marijuana protects against heart rhythm problems. Adherence to the assigned cannabis or abstinence days was imperfect, and the authors said potential withdrawal effects and other behavioral changes could have influenced the results.
“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,” researchers concluded.
The trial, called Marijuana and Acute Risk of Arrhythmia-Joint Abstinence and Exposure, or MARY-JANE, is registered under clinical trial number NCT06021613.