Patients who have an irregular heartbeat after surgery may be at an increased risk of suffering a stroke, according to researchers at Weill Cornell Medical College.

The study’s researchers discovered that patients who were newly diagnosed with atrial fibrillation (AF) while in the hospital for surgery were more likely to have a stroke over the next few years in comparison to patients who did not suffer from AF. Patients whose surgery did not involve the heart appeared to be at a greater risk for stroke, compared to patients who underwent cardiac surgery. This suggests that AF may trigger a reaction in the body to the emotional and physical stress of surgery, causing a higher risk of stroke.

Atrial fibrillation (AF) is the most common form of arrhythmia, or irregular heartbeat. AF occurs when rapid, disorganized electrical signals make the upper two chambers of the heart begin to fibrillate, or contact very quickly and irregularly.

One of the lead study authors, Dr. Gino Gialdini, a post-doctoral research fellow in the Feil Family Brain and Mind Research Institute at Weill Cornell, says that patients with AF following surgery need to be closely observed over time to ensure their health is kept in check.

“Many physicians view AF resulting from surgery as a temporary condition, and current guidelines don’t make specific recommendations for carefully monitoring these patients over time. Our study suggests that AF after surgery requires careful long-term follow-up. We tracked patients whose surgery led to AF and found it significantly increased their long-term risk of stroke,” said Dr. Gialdini in a statement.

The researchers looked at approximately 1.7 million patients hospitalized for surgery, and discovered that 1.4 percent of them had a new diagnosis for AF. The researchers also discovered that one percent of these patients with a new AF diagnosis suffered a stroke one year following their discharge from the hospital.

Dr. Gialdini says that even though these rates aren’t significantly high, even a brief occurrence may be a sign of stroke risk in the future.

The findings of the study are published in JAMA.