The loss of a partner is an emotionally devastating experience that can leave you heartbroken — literally. New research published in the online journal Open Heart found that the death of a life partner can increase the risk of developing an irregular heartbeat for up to a year.

An abnormal heartbeat, also known as atrial fibrillation, is the most common type of heart arrhythmia, affecting an estimated 2.7 to 6.1 million people in the United States according to the Centers for Disease Control and Prevention. The condition, which is marked by a change in the heart’s beating pattern, is a risk factor for death, stroke, and heart failure.

Researchers collected data from nearly 89,000 people newly diagnosed with atrial fibrillation and more than 886,000 age-matched and sex-matched healthy controls between 1995 and 2014. They looked at several factors that might contribute to the risk of developing an irregular heartbeat, including age, sex, and underlying heart conditions, such as heart disease and diabetes. Of those diagnosed with atrial fibrillation, more than 17,000 had experienced partner bereavement, or a state of grief due to the loss of a spouse or lover, as had nearly 167,000 of the comparison group.

The data showed that among those with the condition, underlying illnesses like cardiovascular disease and diabetes were common. However, healthy individuals who had been bereaved had a 41 percent higher risk of developing an irregular heartbeat for the first time than those who had not experienced such a loss. This risk was greatest eight to 14 days after a death and highest among people under the age of 60 — this group was more than twice as likely to develop an irregular heartbeat if they had been bereaved. After a year, their risk was similar to that of someone who had not lost a loved one.

Researchers found that the risk was even higher in those whose partners’ death had been completely unexpected. This group, whose partners seemed relatively healthy the month prior to their death, were 57 percent more likely to develop atrial fibrillation. This increase was not seen in those whose partners were already in bad shape health-wise before they died.

Losing a partner is a major life-altering experience that can bring on an emotional turmoil of grief and depression. These intense feelings have been shown to manifest in physical, sometimes life-threatening, ways, with studies linking bereavement to an increased risk of cardiovascular disease, mental illness, and even death .

The factors underlying bereavement and atrial fibrillation are unknown. However, researchers believe the acute stress associated with losing a partner may adversely impact heart rhythms, prompting the production of chemicals that are involved in inflammation, which is undoubtedly present in atrial fibrillation.

Source: Graff S, Fenger-Gron M, Christensen B, et al. Long-Term Risk of Atrial Fibrillation After the Death of a Partner. Open Heart. 2016.