Marijuana use linked with increased risk of cardiac arrhythmia

By Dr Jonathan Shurlock

The Multi-Ethnic Study of Atherosclerosis (MESA) is a medical research study initiated in 1999, including 6,000 participants, and set up to explore early or subclinical atherosclerosis. Harding et al. have taken a subset of data from this large study in order to explore the relationship between marijuana use and cardiac arrhythmias, in the context of increasing world wide use of the drug, including those over 65 years old.

The present study was a cross-sectional assessment of any association between current or past marijuana use and history of cardiac arrhythmia. 1,485 participants underwent ambulatory ECG monitoring during the most recent follow up phase of MESA. The same participants completed a survey which included questions on past and current marijuna use.

140 (10%) of participants reported marijuna use, with 3% currently using it. Compared with those who had never used marijuana, users were younger and more likely to be male.

Participants reporting current use of marijuana had more episodes of supraventricular tachycardia per day (adjusted geometric mean ratio [GMR] 1.42, 95% confidence interval [CI] 0.87 to 2.32), more premature atrial contractions/hour (GMR 1.22, 95% CI 0.72, 2.13), and more non-sustained ventricular tachycardia (NSVT)/day (GMR 1.28, 95% CI 0.95 to 1.73) than those who had never used it. More frequent marijuana use was associated with a higher burden of NSVT (GMR 1.56, 95% CI 1.13, 2.17). Interestingly a similar relationship was not seen with past marijuana use, whereby the results were primarily null.

The authors conclude that current marijuna use is associated with a greater cardiac arrhythmia burden and that the impact of this on adverse cardiovascular outcomes is unclear. These results reinforce the importance of an accurate substance history when considering the underlying pathology in patients presenting with arrhythmia.

See the full study here: