Cannabis, methamphetamine, cocaine, and opiate use are associated with a significant increase in atrial fibrillation (an irregular heartbeat), according to a new observational study by the American Heart Association. The research suggests the substances could increase the risk of long-term heart conditions.
“To my knowledge, this is the first study to look at marijuana use as a predictor of future atrial fibrillation risk,” said principal investigator Gregory Marcus in a statement.
To understand how recreational drugs may affect atrial fibrillation (AF), the researchers analyzed over 23 million California residents that had required medical intervention from 2005-2015. Many of them reported using cannabis (132,000), while a smaller proportion had used methamphetamine (98,000), cocaine (49,000), and opiates (10,000).
Across the 10 years, almost one million people in the cohort developed AF. When adjusted for risk factors and factoring in drug use, the researchers discovered a significant increase in the risk of developing AF for those using various substances. Methamphetamine posed the greatest risk at 86 percent – but a surprising result was cannabis increasing the risk by 35 percent.
“Despite exhibiting a weaker association with incident AF than the other substances, cannabis use still exhibited an association of similar or greater magnitude to risk factors like dyslipidemia, diabetes mellitus, and chronic kidney disease. Furthermore, those with cannabis use exhibited similar relative risk of incident AF as those with traditional tobacco use,” the study authors write.
The study was not looking for a link between AF and cannabis, but the connection was clear. It likely stems from inhaled particulates leading to inflammation, which is a known risk factor for AF, but there could also be other mechanisms at work.
“It’s also intriguing to consider that inhaled substances travel directly from the lungs to pulmonary veins, which empty into the left atrium, and that the pulmonary veins and the left atrium are especially important in generating AF,” Marcus continued.
AF is often a precursor to more serious conditions, often resulting in a blood clot forming and blocking vital blood vessels. AF-related strokes cause over 150,000 deaths each year in the US, and affects an estimated 12.1 million people in the US alone. If commonly-used substances are significantly boosting rates of AF, this should be involved in clinical advice, particularly for high-risk patients.
The study was published in European Heart Journal.