Marijuana use may increase the chances of developing an often temporary but still frightening heart condition, suggests new preliminary research presented this week at the annual American Heart Association Meeting.

Researchers analyzed records from the country’s largest database on hospital stays, called the National Inpatient Sample (NIS). They looked at over 33,000 people hospitalized with stress cardiomyopathy, better known as “broken heart syndrome,” from 2003 to 2011. When they focused on the 210 patients who reported using marijuana soon before they experienced its telltale symptoms, which closely resemble a heart attack, they found noticeable differences between them and the typical sufferer. Not only were these patients often younger men instead of older women, but they had fewer known risk factors for the condition, like high blood pressure or type 2 diabetes. They were also slightly more likely to go into cardiac arrest and require an implanted defibrillator to prevent later cardiac events (2.4 percent vs 0.6 percent).

These differences could indicate that marijuana alone can increase the risk of stress cardiomyopathy, the researchers concluded. After accounting for other known factors, they estimated that users were nearly twice as likely to develop it than non-users.

“The effects of marijuana, especially on the cardiovascular system, are not well known yet. With its increasing availability and legalization in some states, people need to know that marijuana may be harmful to the heart and blood vessels in some people,” said study author Dr. Amitoj Singh, chief cardiology fellow at the St. Luke’s University Health Network in Bethlehem, Pennsylvania, in a statement.

Stress cardiomyopathy, as previously explained by Medical Daily, is a peculiar uncommon heart condition first reported among Japanese women. It describes a sudden weakening of the heart that triggers chest pain, shortness of breath, and other heart attack-like symptoms. As both its formal and catchier name imply, it usually happens after someone experiences a great deal of emotional or physical stress. There’s no surefire way to know when it will occur in someone, but age and other factors common to cardiovascular disease do seem to make people more vulnerable. Unlike other heart conditions, though, its symptoms are typically temporary, rarely lasting more than a day, and sufferers aren’t more likely to get it again down the road — usually at least.

As Singh notes, marijuana’s role in causing heart issues has been difficult to pin down. Some research has found an increased frequency of cardiovascular disease among users, and a study of mice published earlier this July found evidence that its secondhand smoke can be just as harmful to blood vessels as plain old tobacco smoke. Elsewhere, however, other researchers have theorized that while marijuana smoke can be harmful, its active components (THC and cannabinoids) may actually slow down the progression of atherosclerosis, or the hardening and narrowing of arteries. So conflicting are these findings that some have coined it the “marijuana paradox.”

This latest study can only point to a possible link between pot and a broken heart, Singh cautioned, and its findings have not yet been published in a peer-reviewed journal. Regardless, his team hopes their efforts can guide further research in the area as well as highlight marijuana’s potential health risks — risks particularly relevant given that five more states have passed resolutions to legalize its recreational use this past election.

“If you are using marijuana and develop symptoms such as chest pain and shortness of breath, you should be evaluated by a healthcare provider to make sure you aren’t having stress cardiomyopathy or another heart problem,” Singh said.

Source: Singh A, Agrawal S, Fegley M, et al. Marijuana (Cannabis) Use is an Independent Predictor of Stress Cardiomyopathy in Younger Men. American Heart Association Scientific Sessions 2016. 2016.