After a median follow-up of more than 20 years, researchers found an increased risk of non-ST elevation myocardial infarction (non-STEMI) in patients with atrial fibrillation even when adjusting for cardiovascular and other risk factors. However, there was no association between atrial fibrillation and STEMI.
Lead researcher Elsayed Z. Soliman, MD, director of the Epidemiological Cardiology Research Center at Wake Forest Baptist Medical Center, and colleagues published the findings of the Atherosclerosis Risk in Communities study online in Circulation on April 27.
Approximately two-thirds of MI’s in the U.S. each year are non-STEMI, according to the researchers. In addition, an estimated 2.7 million to 6.1 million people in the U.S. have atrial fibrillation, which is a risk factor for stroke. However, researchers said it was unclear if the disease was a risk factor for MI.
In this community-based population study, researchers examined 15,792 adults who were interviewed and visited a clinic between 1987 and 1989. They followed up with them on several occasions from 1990 to 2013 and excluded patients who did not have quality echocardiograms at baseline and those with coronary heart disease.
The final analysis included 14,462 patients. The mean age was 54 years, 56 percent of patients were women and 26 percent were African American.
Of the patients, 31 had atrial fibrillation at baseline and 1,514 had atrial fibrillation during the follow-up period before having MI.
During a median follow-up period of 21.6 years, researchers identified 1,374 incident MI events by contacting patients and examining hospital medical records. There were 829 non-STEMI events and 249 STEMI events. The mean time from atrial fibrillation diagnosis to MI was 4.82 years.
Researchers found atrial fibrillation was associated with a 63 percent increased risk of MI. There was a significantly higher rate of MI in women with atrial fibrillation compared with men.