The Heart Institute at Virginia Mason in Seattle provides diagnosis and treatment for atrial fibrillation.
Atrial fibrillation (AF) occurs when the upper chambers of the heart "fibrillate" or beat unusually fast. It is a common heart rhythm disorder affecting more than 2 million people in the United States. Each year more than 160,000 new cases are diagnosed. The risk of AF increases with age but can be seen in people as young as 40. It is commonly associated with high blood pressure and heart disease.
Atrial fibrillation is caused by a disturbance in the electrical conduction system in the heart, resulting in the atrial (upper) and ventricular (lower) chambers beating out of sync with one another. Untreated, the condition can lead to the formation of blood clots, increasing the risk of stroke. Symptoms can include a sensation of the heart beating rapidly (palpitations), shortness of breath, fatigue, fainting, and difficulty breathing when lying down.
Diagnosing atrial fibrillation
During a physical exam, your physician may hear a rapid heartbeat with a stethoscope. He or she also may detect an irregular or rapid pulse and low blood pressure. Tests to confirm a diagnosis of atrial fibrillation — and any underlying heart condition that may be causing it — might include the following:
This test, performed in the electrophysiology lab, measures your heart's electrical activity. Electrodes attached to your skin record electrical impulses that appear as waves on a monitor. During atrial fibrillation, the waves appear irregular and taller and closer together than do normal heart rhythms.
To determine the extent or frequency of atrial fibrillation, your physician may recommend that you wear a Holter monitor for 24 hours to record — similar to the ECG — your heart's electrical activity. This small recording device can be worn on a belt or tucked inside a pocket.
This procedure uses sound waves (ultrasound) to produce a video image of your heart beating. A complete survey is taken of your heart chamber sizes and function, as well as the shape and function of all of the heart valves and heart pressures. Therapy of atrial fibrillation is directed toward eliminating the rhythm disturbance as well as improving any underlying heart abnormality. Echocardiography can be performed before and right after an exercise test to look for signs of coronary blockage.
Cardiac catheterization and angiography
During this exam, a catheter is inserted into a blood vessel in your arm or groin and carefully maneuvered toward your heart. The coronary arteries are evaluated by gentling injecting dye along with blood flowing into the arteries, to identify areas of cholesterol blockage. You will have a mild sedative to help you relax before undergoing this procedure.
Your ability to walk a short distance across a room or walk on a treadmill while wearing electrodes attached to your skin (ECG exercise testing) allows your physician to determine your exercise capacity, look for rhythm disturbances and to look for indirect signs of coronary blockage.
Treating atrial fibrillation
Medical therapy versus surgery
Medical treatment for atrial fibrillation includes warfarin or aspirin and a heart rate-controlling drug such as a calcium channel blocker or beta blocker. Antiarrhythmic agents such as beta blockers or more potent drugs such as sotalol, amiodarone, dofetilide, or propafenone are frequently used; however, the medications come with side effects and have not always worked to control the arrhythmia. Studies have shown that medications to keep the heart in regular rhythm are no better than using rate control and blood thinning drugs. Catheter ablation or Surgery offers the best chance of curing atrial fibrillation.
Catheter ablation of atrial fibrillation involves tracking a sterile set of tubes and wires into the upper heart chambers, identifying the source of the atrial fibrillation at the top of the left atrium where the blood flows in from the lungs (pulmonary veins). Radiofrequency energy is used to produce a series of scars which isolate the atrial fibrillation source from the rest of the heart tissue, and prevent re-occurrence of atrial fibrillation.
Who is a candidate for minimally invasive ablation surgery for atrial fibrillation?
Patients with intermittent (paroxysmal or persistent) atrial fibrillation are the best candidates for this procedure, and they are candidates even if their condition has been long standing. Patients with this type of atrial fibrillation see a cure rate above 80 percent with minimally invasive ablation surgery.
Patients with continuous, or permanent, atrial fibrillation — the more intractable or harder to treat form — may have relief of symptoms about 50 percent of the time. Men and women who are extremely limited in their activities because of atrial fibrillation, as well as patients who have failed previous medical treatments or ablations, are eligible for this surgery.
Minimally invasive ablation surgery
Patients arrive at Virginia Mason in the morning for pre-op procedures then undergo a two- to three-hour surgery in the afternoon. The procedure involves placement of three entry ports, each one-half to three-fourths inches in size, in the chest. Cardiothoracic surgeons then access the surface of the heart through the ports using a catheter that delivers microwave energy, causing heat injury — ablation — to targeted tissue.
While the patient is in the operating room, electrophysiology studies are taken to determine that normal conduction (electrical flow) has been blocked. Most patients are able to maintain a stable heart rhythm after surgery.
What patients can expect following surgery
A small drainage tube is inserted in the chest following surgery. Most patients have a one-night stay in the hospital and are home the following day. Patients might experience three days of decreased energy, but most are back to their normal activities in one week.
The catheter ablation and the new surgery are often so successful that patients, particularly those with paroxysmal atrial fibrillation, may be able to stop taking their medications. However, some patients will need to continue medical therapy.