A new study into the effects of marijuana on heart failure patients has shocked researchers by suggesting that marijuana can actually reduce symptoms and risks of death, LiveScience.com reports.

The findings suggest that marijuana users weren’t as likely to suffer from atrial fibrillation, a condition marked by an irregular heartbeat that can cause strokes, heart failure, and blood clots. The study compared patients with heart failure who use marijuana to those who don’t.

While the study is currently unpublished, Dr. Oluwole Adegbala, a medical resident at Englewood Hospital and Medical Center in New Jersey, presented it at the recent American Heart Association’s Scientific Sessions’ meeting in California. The outcome stood in contrast to what Adegbala and the other investigators expected.

Other research suggests a connection between smoking marijuana and poor cardiovascular health. “One of the few things scientists know for sure about marijuana and cardiovascular health is that people with established heart disease who are under stress develop chest pain more quickly if they have been smoking marijuana than they would have otherwise,” reads a Harvard University article on marijuana and heart health. “Research suggests that the risk of heart attack is several times higher in the hour after smoking marijuana than it would be normally…Although the evidence is weaker, there are also links to a higher risk of atrial fibrillation or ischemic stroke immediately following marijuana use.” Photo via Flickr/Simon Fraser University
And yet, after studying data from over 6 million heart failure patients admitted to the hospital between 2007 and 2014, Adegbala found that marijuana users were less likely to experience atrial fibrillation. Even more striking, dependent marijuana users—those who use the drug frequently, on a daily basis—were 31 percent less likely to suffer atrial fibrillation than nonusers. This number is even higher than nondependent marijuana users, who were 18 percent less likely to suffer atrial fibrillation, according to LiveScience. The dependent patients, the study found, also lowered their risk of fatality while in the hospital by 58 percent compared to non-users, with nondependent patients lowering their risk by 46 percent. In other words, the more weed the patients smoked, the better off they were.

“I was very surprised,” Adegbala told LiveScience.

Adegbala says that the discrepancy between this study and other findings may have to do with factors that weren’t previously accounted for, like other drug use. This may have resulted from the difficulty in studying marijuana as a Schedule I drug.

Adegbala speculates that marijuana’s positive effect on heart failure patients may have to do with the plant’s anti-anxiety properties, which reduce blood pressure, and anti-inflammatory properties.

Despite these findings, the researchers do not currently recommend using marijuana as a treatment for heart conditions as further research needs to be done. It’s also important to note that Adegbala’s study is yet to appear in a peer-reviewed journal.

For now, heart failure patients should take these findings with a grain of salt. One study, especially when not peer-reviewed or published, is not nearly enough to call the evidence conclusive. But it’s a start.