Atrial Fibrillation: A Leading Risk Factor for Stroke
Heartmail Winter 2019
DECEMBER 20, 2018
Treatment options include medications and non-invasive procedures
Atrial fibrillation, so named because it causes rapid, irregular beating of the heart’s upper chamber, or left atrium, is the most common type of heart rhythm disorder.
Afib affects 3 to 6 million individuals in the U.S., resulting in symptoms that include a racing heartbeat, dizziness and shortness of breath.
“Because rapid contractions are much weaker than the steady contractions of a normal beating heart, blood flow in the atrium significantly slows down in patients with atrial fibrillation,” says Zimetbaum (right), Associate Chief of Cardiovascular Medicine and Director of Clinical Cardiology at Beth Israel Deaconess Medical Center and the Richard A. and Susan F. Smith Professor of Medicine at Harvard Medical School. “As a result, blood fails to move out of the atria and can then pool and clot. Blood clots are especially prone to form in a pouch-like area of the atria called the left atrial appendage.”
If a blood clot breaks loose and travels to the brain, it can cause a stroke. In fact, patients with atrial fibrillation have a five times higher risk of stroke than the general population, according to the American Heart Association/American Stroke Association.
Preventing strokes is a key factor in determining treatment strategies for atrial fibrillation. Depending on the individual patient, therapies might include medications or minimally invasive procedures.
Anticoagulant Medications for Stroke Prevention
Anticoagulants, or blood thinning medications, are typically the first step in managing atrial fibrillation. These include warfarin as well as a newer class of blood thinners.
Lynn Schweikart first experienced symptoms of atrial fibrillation about 10 years ago when she awoke with a “pounding” heart. Although that episode resolved itself, several years later, her racing heartbeat recurred and episodes gradually began to increase in frequency, eventually occurring every few months.
“Even though these periods of rapid heartbeats became more frequent, they always went away on their own,” says Schweikart, a writer and marketing consultant. “When I did begin seeing Dr. Zimetbaum, he recommended I start taking a blood thinner, which I wasn’t crazy about.”
Although warfarin is effective in preventing clots, it can be difficult for patients to keep their daily medication levels within the narrow range necessary to prevent side effects such as unwanted bleeding.
“For me, one of my biggest concerns about being on the blood thinner was a fear of falling — and the possible risk of an uncontrollable bleed,” says Schweikart. “I started avoiding some of my favorite activities, including bicycling.”
Left Atrial Appendage Occlusion
Earlier this fall, after returning from a three-week tour of South Africa with her choral group, Schweikart underwent a procedure called left atrial appendage occlusion. In this minimally invasive procedure, a tiny device called the Watchman™ is implanted at the opening of the left atrial appendage, thereby preventing blood clots from escaping and reaching the brain.
“For atrial fibrillation patients who have unsuccessfully tried other treatments, the Watchman provides another option to guard against stroke,” says Zimetbaum.
The implant functions like a small stent to close the left atrial appendage. It is inserted through a narrow tube by way of a small incision in the upper leg. The procedure is done under general anesthesia and takes about an hour. Patients commonly stay in the hospital overnight and leave the next day. The Watchman device is a one-time implant and does not need to be replaced.
“How we manage atrial fibrillation depends on the individual patient,” says Zimetbaum. “We carefully consider a patient’s age, health and lifestyle. As we continue to learn more and as new procedures and treatments become available, the need to protect atrial fibrillation patients from stroke is always a primary goal.”
Above content provided by the CardioVascular Institute at Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.