Heart Arrhythmias Unknown Stroke Cause

Paroxysmal atrial fibrillation may cause unexplained strokes

(RxWiki News) About 33 percent of stroke survivors leave the hospital unsure of the cause. A new finding suggests about 20 percent of strokes with an undetermined cause may have been prompted by a heart arrhythmia episode.

The strokes were caused by intermittent atrial fibrillation, a common heart rhythm disorder that can be a permanent condition for some patients, a new study found.

"Talk to your doctor about how to lower your risk of a recurrent stroke."

Dr. Daniel J. Miller, the study’s first author and a senior staff neurologist at Henry Ford Hospital, said that identifying patients with a temporary heart arrhythmia could reduce recurrence of stroke by 40 percent as compared to simply treating them with aspirin.

The research confirmed the findings of a smaller 2008 study, which suggested that 23 percent of stroke survivors whose stroke had been caused by an unidentified cause had intermittent atrial fibrillation. Episodes can last for several seconds or several days.

That study had suggested that abnormal heart rhythms lasting less than 30 seconds could lead to longer atrial fibrillation episodes that cause small blood clot formation in patients' hearts.

During the current study researchers reviewed the medical records of 156 patients, evenly split between men and women, who received three weeks of outpatient cardiac monitoring about six months after a stroke or mini stroke. Most were not taking prescription blood thinners.

They found that 17.3 percent of participants had at least one atrial fibrillation episode during monitoring, and the number increased the longer they were monitored. After two days 3.9 percent had atrial fibrillation episodes. That number rose to 9.2 percent after one week, 15.1 percent after two weeks and hit 19.5 percent at three weeks.

Patients found to have premature atrial contractions, a common form of erratic heartbeat, when they entered the study were 13.7 times more likely to experience intermittent atrial fibrillation than those without an abnormal heart rhythm.

Other stroke risk factors researchers identified included those with a reduction in blood pumped by the heart or whose heart's left atrium was enlarged by at least one centimeter in diameter. Women also were found to have a risk 6.2 times higher than men of developing intermittent atrial fibrillation.

In order to prevent future strokes, researchers urge that patients receive outpatient cardiac monitoring for at least three weeks to potentially identify atrial fibrillation that could lead to another stroke.

The research was presented Thursday at the American Stroke Association’s International Stroke Conference 2012 in New Orleans.

Review Date: 
February 1, 2012