Frequent pot smokers are more than twice as likely to suffer a stroke compared with those who don’t partake, the first study found.
They’re also more likely to be hospitalized for a dangerously erratic heart rhythm, according to the second study.
Both studies are to be presented at an upcoming meeting of the American Heart Association (AHA), in Philadelphia, Nov. 16 to 18. Research presented at meetings is typically considered preliminary until published in a peer-reviewed journal.
The findings are “thought provoking at a time when there is a great push to legalize marijuana, and the herb and its metabolites are being promoted as a cure-all for a myriad of medical conditions and ailments,” said Dr. Ranjit Suri, an electrophysiologist at Mount Sinai St. Luke’s in New York City. Suri was not part of either study.
The first study found that non-smokers who use marijuana more than 10 days a month are nearly 2.5 times more likely to have a stroke versus non-users.
For the study, researchers evaluated federal survey data on more than 43,000 adults, aged 18 to 44, of whom about 14% reported using pot in the last 30 days.
The study team was surprised that people so young had such an elevated stroke risk, said lead author Tarang Parekh, a health policy researcher at George Mason University in Fairfax, Va.
“Young cannabis users, especially those who use tobacco and have other risk factors for strokes, such as high blood pressure, should understand that they may be raising their risk of having a stroke at a young age,” he said.
Prior studies have shown that marijuana can increase blood clotting and cause arteries to narrow, both of which can increase the risk of stroke, Parekh said.
This might explain the observed association.
In the second study, researchers found that people who compulsively use cannabis have an up to 50% greater risk of being hospitalized for an arrhythmia – an erratic heartbeat that can increase risk of stroke, heart attack or heart failure.
The team compared more than 570,000 people hospitalized with an arrhythmia against more than 67 million patients hospitalized for other reasons, looking specifically at those diagnosed with cannabis-use disorder.
People aged 25 to 34 who compulsively used cannabis were 52% more likely to land in the hospital suffering an arrhythmia, the researchers found, while those aged 15 to 24 were 28% more likely to be hospitalized for an irregular heartbeat.
“The effects of using cannabis are seen within 15 minutes and last for around three hours.
At lower doses, it is linked to a rapid heartbeat.
At higher doses, it is linked to a too-slow heartbeat,” said lead researcher Dr. Rikinkumar Patel, a resident physician in the department of psychiatry at Griffin Memorial Hospital in Norman, Okla.
Doctors need to ask new stroke and heart patients about their marijuana use to better inform their treatment options, both sets of researchers concluded.
“The risk of cannabis use linked to arrhythmia in young people is a major concern, and physicians should ask patients hospitalized with arrhythmias about their use of cannabis and other substances because they could be triggering their arrhythmias,” Patel said.
However, both studies were observational and do not establish a direct cause-and-effect link between marijuana use and these conditions, Suri noted.
With increasing legalization, marijuana has become the most commonly abused substance in the United States.
Together with the introduction of more potent marijuana products over the years, more adverse events are being reported and clinically characterized. Delta-9-tetrahydrocannabinol (THC) is the active psychotropic component of marijuana, which acts mainly on G-protein cannabinoid receptors CB1 and CB2.
Multiple isolated cases of arrhythmias associated with marijuana use have been published. In this manuscript we conduct a scoping study of a total of 27 cases of arrhythmia associated with marijuana. Most cases were reported in young males (81%) with a mean age of 28 ± 10.6 years.
Atrial fibrillation (26%) and ventricular fibrillation (22%) were the most common arrhythmias reported. Brugada pattern was reported in 19% of the patients.
Marijuana associated arrhythmia resulted in a high mortality rate of 11 %.
While the exact mechanisms of arrhythmias associated with marijuana are not clear, several hypothesis have been introduced including the effect of marijuana on cardiac ion channels as well as its effects on the central nervous system.
In this paper we discuss the possible mechanisms of marijuana induced arrhythmia citing the evidence available to-date.
Marijuana is the most common drug of abuse in the United States .
In 2016, a national drug survey indicated that lifetime marijuana use in ages 12 years or older was approximately 118 million in the United States .
The potency of marijuana has seen a tenfold rise in the past decade . Implementation of medical marijuana laws in the period from 2004–2012 lead to an overall 15 percent increase in the probability of almost daily or daily marijuana use among adults aged 21 years or above .
Certain states in the United States of America which have legalized marijuana for recreational use have reported a higher rates of marijuana use when compared to states where all forms of marijuana is illegal [5,6,7].
Multiple isolated cases of arrhythmias associated with marijuana use have been reported. We present a scoping of the same.
On August 27th, 2018, a systematic search was conducted using Pubmed, Google Scholar, CINAHL, Cochrane CENTRAL and Web of Science databases. Studies listing the keywords “Marijuana, cannabis, arrhythmias, atrial arrhythmia, ventricular arrhythmia” were used to identify cases of myocardial arrhythmias associated with marijuana use (Figure 1).
The reference list of each report was reviewed for potential additional cases. All cases were reviewed in detail. Data reviewed included demographic data, cardiovascular (CV) risk factors, electrocardiography (EKG) findings, troponin levels, transthoracic echocardiography, electrophysiology study, urine drug screen findings, and management when available.
A total of 27 cases of arrhythmias associated with marijuana use were identified from 24 papers (Table 1) (8–31). The mean age was 28 ± 10.6 years (median age 24 years) and 81% were males. The other reported risk factors were: smoking in 22%, hypertension in 11%, alcohol abuse in 11%, use of other drugs of abuse in 11%, hyperlipidemia in 7.4%, coronary artery disease in 3.7%, and family history of sudden cardiac death in 3.7%.
Atrial fibrillation was the most common arrhythmia (26%) followed by ventricular fibrillation (22%). Brugada pattern was reported in 19%. All reported arrhythmias have been summarized in table 2. Urine toxicology screen was positive for marijuana in 41% of the cases. The management strategy employed has been summarized in table 1. Death occurred in 3 cases (11%) of which ventricular fibrillation was the cause in 2 cases (7.4%) sudden cardiac death in one (3.7%).
More information: Harvard Medical School has more about marijuana and heart health.