June 19, 2008 Doctors at the Cedars-Sinai Heart Institute were among the first in California to offer an experimental therapy for atrial fibrillation using the WATCHMAN® Left Atrial Appendage System. This is a multicenter Phase II clinical trial, and Cedars-Sinai is one of about 60 centers nationwide participating in the study.
Compared to people with normal heart rhythm, patients who have atrial fibrillation -- the upper chambers of the heart quiver instead of pumping effectively -- have a five-fold increased risk of suffering a clot-related stroke. Blood clots commonly form in the left atrial appendage, a pouch attached to the left atrium, and travel to the brain, blocking the flow of oxygenated blood.
Use of the blood thinner Coumadin (warfarin) has been considered standard medical treatment to reduce the risk of stroke in atrial fibrillation patients, but it is associated with increased risk of bleeding problems. The left atrial appendage can be removed surgically -- it serves little if any useful purpose -- but surgery is not always an option.
Aging, high blood pressure, diabetes and other conditions increase stroke risk in atrial fibrillation patients. Many of these same conditions cause patients to be poor candidates for surgery and long-term blood thinner therapy.
The WATCHMAN® Left Atrial Appendage System, developed by Atritech, Inc., is designed to form a mechanical barrier that seals off the entrance to the appendage and prevents clots from forming. It is threaded to the heart through blood vessels, starting at the groin. Once in place, the umbrella-like device is deployed, plugging the entrance to the appendage, and the catheter is withdrawn.
Atrial fibrillation occurs when faulty nerve impulses cause the atria to beat erratically. Using traditional or minimally invasive operating techniques, surgeons may apply heat or freezing temperatures to interrupt these nerve messages and restore normal rhythm. They also may remove the left atrial appendage as part of the procedure to prevent the possibility of future clot formation.
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