Yes, physicians warn, cannabis is bad for the heart

Cannabis use is on the rise throughout the United States, but it is not as harmless as some people may believe. In fact, according to a new in-depth analysis in Nature Reviews Cardiology, regular cannabis use increases a person’s risk of multiple adverse cardiovascular outcomes, including myocardial infarction, arrhythmias and cardiomyopathy.[1]

The study’s authors, a group of researchers with the Stanford Cardiovascular Institute, explored a wide variety of topics, including ongoing policy trends related to cannabis and the science behind why it appears to make such a significant impact on the cardiovascular system. The group also emphasized that it will be important to learn more about the long-term impact of cannabis use as time goes on. 

“Cannabis is emerging as a risk factor for adverse cardiovascular health,” wrote first author Mark Chandy, MD, PhD, who is now an assistant professor at Western University in Ontario, Canada, and colleagues. “With changing public perceptions and an overall decline in tobacco use, cannabis is poised to replace tobacco as a legal drug of choice. Previous restrictions are ending with the widespread decriminalization and legalization of cannabis, boosting use of the drug. A public perception that cannabis is harmless and therapeutically beneficial persists, despite mounting evidence from preclinical and clinical studies showing that cannabis use can harm the cardiovascular system and pose other serious health problems, not unlike tobacco.”

Exploring the link between cannabis use and cardiovascular disease

Chandy et al. noted that “robust evidence from basic science and clinical studies” has already linked cannabis use to an increased likelihood of developing cardiovascular disease. These risks appear to become more severe depending on how often the drug is used. 

Another key takeaway from the group’s assessment was the evidence that cannabis use can increase the risk of new-onset arrhythmias such as atrial fibrillation (AFib) and atrial flutter. 

“Cannabis use disorder, defined as an inability to stop using marijuana despite adverse health effects or social problems, is associated with increased occurrence of AFib, hospital admissions for uncontrolled AFib and thromboembolic events,” the authors wrote. “Moreover, cannabis use disorder and associated arrhythmias are more common in younger patients. After cannabis exposure, heart rate transiently increases due to increased sympathetic tone and decreased parasympathetic tone. The chronic use of cannabis results in bradycardia due to reversal of autonomic tone. Moreover, the burden of cannabis-related arrhythmic events is exacerbated in individuals with ischemic heart disease compared with those without.”

The regular use of cannabis also appears to increase a person’s risk of developing cardiomyopathy, and some studies have linked it to an increased heart failure risk. 

Synthetic cannabis: a cause for concern?

The authors also warned that there are now synthetic marijuana strands that “exert strong depressant effects when combined with alcohol” and are “far more potent” than traditional cannabis. 

“Clinical reports and case studies provide insight into the acute adverse effects and potential complications associated with the recreational use of synthetic cannabinoids, including respiratory depression, cardiovascular events, neuropsychiatric symptoms and death,” the authors wrote. “The use synthetic cannabinoids has also been linked to myocardial infarction, myocardial ischemia and other cardiovascular complications, particularly in pediatric patients.” 

Consuming tobacco and cannabis together could lead to even greater risks

The review also examined the fact that more and more people are now using cannabis and tobacco together, creating the potential for even worse patient outcomes. At this point, little is known about the long-term effects of combining these two substances, but the short-term evidence we have so far all points to “harmful health outcomes.”

Click here to read the full review, which covers decade of research and includes nearly 150 references.