Atrial Fibrillation Complications: Blood Clots, Heart Failure

The severity of atrial fibrillation varies from individual to individual. Complications, which can include blood clots, stroke and congestive heart failure, are often directly related to the heart rate: the faster the heartbeat, the greater the chance of complications.

Once a heart rate exceeds 130 beats per minute, people usually begin to experience uncomfortable symptoms. Patients may experience noticeable heart palpitations and difficulty breathing. They may also report feeling weak or faint during episodes of atrial fibrillation.

People living with atrial fibrillation have five times the normal risk of stroke. During atrial fibrillation, the irregular heartbeat prevents the atrial chambers from contracting effectively. As a result, blood pools in the atrium, increasing the chance of developing blood clots. These blood clots may break free and leave the heart, traveling through the circulation. If the clots lodge in the brain, significant injury can result.

The increased risk of stroke is such that chronic atrial fibrillation treatment often includes anticoagulant medication. The anticoagulants reduce the risk of developing blood clots, which in turn reduce the risk of stroke.

Congestive heart failure is a chronic and life-threatening disease that occurs when the heart muscle is too damaged to pump enough blood. As congestive heart failure progresses, blood "backs up" into the lungs, causing breathing difficulties.

Atrial fibrillation can lead to congestive heart failure. Repeated incidences of irregular and rapid heart rhythms slowly weaken the heart muscle, impairing the heart's ability to contract effectively.

A gradual progression from paroxysmal (transitory) atrial fibrillation to chronic (continuing) atrial fibrillation is common. This progression can take years, but is, in many cases, an inevitable complication of the disease. At its most severe, atrial fibrillation becomes permanent: The irregular heart rate cannot be restored to a normal rhythm.

Resources

Beers, M.H. & Berkow, R. (ed). Arrhythmias . The Merck Manual of Diagnosis and Therapy, 17th Edition. Merck Research Laboratories, NJ, 1999.

Fauci, A., Braunwald, E., Isselbacher, K., Wilson, J., Martin, J., Kasper, D., Hauser, S. & Longo, D. (ed). Harrison's Principles of Internal Medicine, 14th Edition. McGraw-Hill, New York, 1998.

Mayo Foundation for Medical Research and Education. (updated 2005). Atrial fibrillation.

National Library of Medicine. (updated 2004). Atrial fibrillation/flutter. MedlinePlus Medical Encyclopedia.