Systematic review finds cannabis smoking linked to heart attacks and cardiovascular disease | Research

The takeaway

A systematic review of 85 publications involving over 541,000 subjects found that the large majority of Level I-III studies highlighted increased cardiovascular risk from cannabis use, including acute coronary syndrome.

Cannabis smokers, cardiologists, emergency physicians, and anyone concerned about cardiovascular health.

23% of case report patients died from cannabis-associated acute coronary syndrome

What the researchers found

Five Level I systematic reviews, 14 Level II studies (83,961 subjects), and 14 Level III studies (457,495 subjects) were identified. All but five of these highlighted increased cardiovascular risk. In 51 case reports (62 subjects, average age 31), 60% showed ST-elevation, 35% had left anterior descending artery involvement, 34% had cardiomyopathy, and 23% died.

Why it matters

Cannabis is widely perceived as cardiovascularly benign, but this extensive review shows a consistent signal of increased heart attack risk, particularly in young adults who would not typically be at risk.

The numbers in context

85 publications, 541,518 subjects. 5 Level I reviews, 14 Level II studies (83,961 subjects), 14 Level III studies (457,495 subjects). Case reports: avg age 31, 60% ST-elevation, 23% died. Only 10% female.

How the study worked

Systematic review of PubMed, Google Scholar, and OpenGrey following PRISMA guidelines. Focused on smoked phytogenic cannabis and acute coronary syndrome. 85 publications covering 541,518 subjects were included.

What this study cannot tell us

No Level I randomized controlled trials specifically address this association. Case reports are inherently biased toward severe outcomes. Most evidence involves smoked cannabis; other forms were excluded.

How to read the evidence

Moderate: large systematic review with extensive literature coverage, though limited by absence of randomized trials.

When this study was published

Published in 2019.

The bigger picture

Heart attacks in young adults who smoke cannabis may be missed or misattributed. The mechanism likely involves sympathetic activation, vascular inflammation, and platelet activation from cannabis smoke.

Questions still open

Does vaporized or edible cannabis carry the same cardiovascular risk? Is the risk dose-dependent? Would switching from smoked to non-combustion methods reduce cardiac events?

Common questions

Can cannabis cause a heart attack?

This review found a consistent association between cannabis smoking and acute coronary syndrome across multiple study types. The risk appears highest shortly after use and in younger individuals.

Is edible cannabis safer for the heart?

This review specifically excluded non-smoked cannabis, so it cannot answer that question. The combustion-related mechanisms (carboxyhemoglobin, smoke-induced inflammation) would not apply to edibles, but other risks (heart rate elevation) might still be relevant.

Read the original research

Cannabis use and acute coronary syndrome.

Clinical toxicology (Philadelphia, Pa.), 57(10), 831-841

View on PubMed ↗Publisher’s paper ↗

Citation

Richards, John R; Bing, Mary L; Moulin, Aimee K; Elder, Joshua W; Rominski, Robert T; Summers, Phillip J; Laurin, Erik G. (2019). Cannabis use and acute coronary syndrome.. Clinical toxicology (Philadelphia, Pa.), 57(10), 831-841. https://doi.org/10.1080/15563650.2019.1601735