By Matthew J. Price, MD, and Douglas Gibson, MD, Scripps Health
A new device currently being studied at select hospitals across the country may eliminate the need for blood thinning medications in some patients who have a heart condition known as atrial fibrillation (“AF”). The most common cause of irregular heartbeat, AF affects more than two million people in the United States. Although it is often seen in patients with high blood pressure, coronary artery disease, lung disease and other conditions, the cause of AF is often unknown. It does become more common with age, especially after age 60, and affects one in ten people over age 80. By the year 2050, it is expected that more than five million Americans will suffer from AF.
AF occurs when the electrical impulses that control the way the heart beats become irregular. Every time the heart beats, the two upper chambers of the heart (the atria) contract, followed by the two lower chambers (the ventricles) in a coordinated and organized fashion. In comparison, during AF the electrical activity in the upper chambers (the atria) becomes very fast and disorganized. When this occurs, the upper chambers (atria) quiver and do not pump blood effectively. Normally, the heart beats between 60 and 100 times per minute, but in people with AF, the heart can race very fast. This can lead to symptoms including shortness of breath, fatigue, chest discomfort and dizziness, although some people with AF have no symptoms at all.
Whether patients have symptoms or not, AF can cause blood to stagnate or pool in the left atrium, creating an ideal environment for blood to clot. These clots most commonly occur in a part of the left atrium called the left atrial appendage. These clots can break loose and travel through the bloodstream and up to the brain, where they can cause a stroke; indeed, patients with AF have six times the risk of stroke than people who have a normal heart rhythm.
In order to reduce the risk of stroke caused by these blood clots, many AF patients take a blood-thinning drug called warfarin (brand name Coumadin). But treatment with warfarin can be challenging for the patient and doctor: if the blood is too thin, it can cause bleeding problems that may be severe and life-threatening, and if the blood is not thin enough, the patient will be at a continued risk for stroke. The level of warfarin can be affected by many things, such as meals, fluctuating weight, medicines, and other factors; therefore, frequent blood tests are required to monitor the thickness of the blood.
A new device, however, may revolutionize the way AF patients are treated. A clinical study underway at Scripps Green Hospital is evaluating the effectiveness of a tiny, parachute-like device called the WATCHMAN® that may reduce the risk of stroke and eliminate the need for blood thinning medications in some AF patients. This novel treatment is the currently the only one of its kind in the United States.
The WATCHMAN is designed to close off the left atrial appendage (the area in the heart where blood can pool and clot), thereby preventing blood clots from going to the brain and enabling patients to safely discontinue warfarin. The device is implanted into the heart without surgery: the patent is given a local anesthetic, and the catheter is inserted through a small incision in the groin and threaded through the vein up to the heart. The procedure takes one to two hours, and patients usually spend one night in the hospital. Patients can stop warfarin 45 days after a successful WATCHMAN implant.
Eligible participants must be eligible to take warfarin and have a history of AF with or more risk factors for stroke, such as age more than 75 years, diabetes, high blood pressure, prior stroke or transient ischemic attack, heart failure. As with any surgical procedure, there are risks, but they are very low. The WATCHMAN study is scheduled to conclude in 2012, and new patient enrollments will likely close that year. Evaluation by the FDA for approval for use of the device in the United States is anticipated in 2013. Patients who are interested in participating should speak with their cardiologists and/or contact research coordinator Maria Reyes at (858)554-8931.
Scripps Health interventional cardiologist Matthew J. Price, MD and Scripps Health cardiac rhythm specialist Douglas Gibson, MD are the principal investigators of the WATCHMAN study. To Your Health is brought to you by the physicians and staff of Scripps Health. For a referral to a Scripps physician, please call 1-800-SCRIPPS.