What Cardiologists Should Know About Marijuana and Heart Risk | Research

The takeaway

Case reports and temporal associations link marijuana inhalation to heart attacks, sudden cardiac death, stroke, and arterial disease, though controlled studies confirming causation are lacking.

Read this if you have heart concerns and want to understand marijuana's cardiovascular effects.

Temporal associations documented between marijuana and MI, sudden cardiac death, stroke, and arteritis

What the researchers found

The review documents temporal associations between marijuana use and several serious cardiovascular events: myocardial infarction (heart attack), sudden cardiac death, cardiomyopathy, stroke, transient ischemic attack, and cannabis arteritis (inflammation of blood vessels).

Marijuana is known to cause tachycardia (rapid heart rate), which could trigger cardiovascular events in vulnerable individuals. It also causes peripheral vasodilation, which can affect blood pressure and cardiac workload.

The authors emphasize that approximately 200 million people use marijuana worldwide, and as decriminalization and legalization expand, cardiologists should expect to encounter these potential complications more frequently. However, they note that the evidence is primarily based on case reports and temporal associations rather than controlled studies.

Why it matters

With expanding marijuana legalization, cardiologists need to be aware of potential cardiovascular risks, particularly for patients with pre-existing heart conditions. The review serves as a clinical alert for a risk that may increase in prevalence as marijuana use becomes more widespread.

The numbers in context

Approximately 200 million marijuana users worldwide. Documented associations: myocardial infarction, sudden cardiac death, cardiomyopathy, stroke, TIA, cannabis arteritis.

How the study worked

This is a brief narrative review focused on cardiovascular, cerebrovascular, and peripheral vascular effects of marijuana inhalation. The authors reviewed case reports, case series, and available epidemiological data linking marijuana use to adverse cardiovascular events.

What this study cannot tell us

The evidence is primarily from case reports and temporal associations, which cannot prove causation. The incidence of cardiovascular events attributable to marijuana is unknown. Many reported cases involved young people where other risk factors may have been present. Dose-response relationships have not been established.

How to read the evidence

This is a narrative review of primarily case reports and temporal associations. Controlled studies confirming cardiovascular causation are lacking.

When this study was published

Published in 2014. Larger epidemiological studies on cannabis and cardiovascular risk have been published since, with ongoing investigation.

The bigger picture

The cardiovascular effects of marijuana are less studied than its neuropsychiatric effects but may be clinically significant, particularly for older users or those with pre-existing cardiovascular disease. As the demographics of cannabis use shift with legalization, cardiovascular risks may become more apparent.

Questions still open

What is the actual incidence of marijuana-associated cardiovascular events? Are edibles safer than smoked cannabis for cardiovascular risk? Should patients with heart disease be specifically counseled about marijuana?

Common questions

How does marijuana affect the heart?

Marijuana causes tachycardia (increased heart rate) and peripheral vasodilation (widening of blood vessels). The increased heart rate can place additional demand on the heart, potentially triggering events in people with existing cardiovascular disease.

Are young people at risk for marijuana-related heart problems?

Most reported cases involved young people, which is notable because cardiovascular events are rare in this age group. However, the absolute risk appears to be very low, and these cases may represent rare events in individuals with unrecognized vulnerabilities.

Read the original research

Adverse cardiovascular, cerebrovascular, and peripheral vascular effects of marijuana inhalation: what cardiologists need to know.

The American journal of cardiology, 113(1), 187-90

View on PubMed ↗Publisher’s paper ↗

Citation

Thomas, Grace; Kloner, Robert A; Rezkalla, Shereif. (2014). Adverse cardiovascular, cerebrovascular, and peripheral vascular effects of marijuana inhalation: what cardiologists need to know.. The American journal of cardiology, 113(1), 187-90. https://doi.org/10.1016/j.amjcard.2013.09.042