Subclinical episodes of atrial fibrillation (AF) predict a significantly increased risk for stroke, according to an international study in the New England Journal of Medicine.

Researchers recruited some 2600 patients aged 65 and over who’d just received a pacemaker or an implantable cardioverter-defibrillator. None had previous episodes of clinical AF. By 3 months, the devices detected subclinical episodes of AF (a heart rate of 190 or more per minute and lasting longer than 6 minutes) in about 10% of patients. Over a mean follow-up of 2.5 years, those with subclinical AF had more than twice the risk for ischemic stroke or systemic embolism as those without subclinical AF.

Asked to comment, Journal Watch Cardiology‘s Dr. Mark Link writes: “Although the current findings are by no means definitive for guiding anticoagulation decisions, they do support taking device-documented subclinical AF seriously. If an asymptomatic patient’s CHADS2 score is high and subclinical episodes are frequent or prolonged, I would consider anticoagulation.”

source:NEJM