What is the Connection Between Atrial Fibrillation and Stroke?

Atrial fibrillation (AF) is a cardiac arrhythmia, or abnormal heart rhythm. It sometimes is connected to a stroke, which occurs when blood flow to an area of the brain is blocked. Atrial fibrillation and stroke occur together when the unsynchronized heart rhythm causes blood to and pool and become sluggish. The pooled blood can form clots. If a clot leaves the heart and travels to the brain, it can block flow of blood through the cerebral arteries and result in a stroke.

Millions of people around the world are affected by AF, and there are countless undiagnosed cases. By itself, atrial fibrillation is not necessarily life-threatening, but it should be treated as a medical emergency. Complications from atrial fibrillation can be debilitating and sometimes fatal. The most serious concern is the connection between atrial fibrillation and stroke.

Atrial fibrillation occurs when electrical impulses to the heart degenerate, causing the two upper chambers of the heart, known as the atria, to beat with an irregular and chaotic rhythm out of coordination with the heart's lower chambers, or ventricles. This rhythm might feel like a fluttering or quivering heartbeat and is often very rapid and weak. The result of this rapid heart rate is poor blood flow, and it is often manifested in symptoms such as shortness of breath, fatigue, weakness and heart palpitations. These symptoms might be disturbing, but the major threat is the possibility of stroke.

The connection between atrial fibrillation and stroke is well documented. Research has shown that about 15 percent of people who have strokes also have atrial fibrillation. A person with atrial fibrillation is five times more likely to suffer a stroke than the person who does not have AF. Atrial fibrillation can occur at any age, but is most likely to affect older people. Approximately 5 percent of people older than 65 have atrial fibrillation, and it is more likely to appear in people who have heart disease, lung disease or high blood pressure.

Strokes caused by blood clots are called ischemic strokes. Ischemic strokes account for about 75 percent of all strokes. The outcome of a stroke depends on where the stroke occurs and how much of the brain is affected. Larger strokes often result in paralysis or death; smaller strokes might leave the victim with weakness on one side of the body, difficulty speaking or other more minor problems.

Proper medical care can manage atrial fibrillation and stroke. Most strokes resulting from atrial fibrillation can be prevented. Diagnosis is critical. Following diagnosis, atrial fibrillation can be treated with therapies designed to return the heart to normal sinus rhythm.

Many patients who have atrial fibrillation are also prescribed blood thinners or anticoagulants that will prevent clots from forming. Anticoagulants can reduce the risk of stroke in atrial fibrillation patients by more than 60 percent. These medications are constantly monitored, and the patient usually makes frequent trips to the doctor’s office to adjust medication levels. Some patients do not need strong prescription medications and are put on aspirin therapy to thin the blood.

As research increases the medical profession’s understanding of atrial fibrillation and stroke, new therapies likely will be developed. Stroke is not the inevitable result of atrial fibrillation, but it is a significant threat. People who have atrial fibrillation are at risk for a stroke and should be under the care of a qualified physician.