There is ongoing discussion among the medical community concerning whether minimal or extensive cardiac ablation is the best treatment for atrial fibrillation. This is the most common cardiac arrhythmia that can sometimes be silent and at other times present with very symptomatic palpitations. Atrial fibrillation can often lead to cerebral infarcts or strokes.
An expert in the field, Dr. José A. Martel, Medical Director of the Cardiac Electrophysiology Department at Kendall Regional Medical Center, in Miami, Florida, explains that ‘fibrillation’ is the spontaneous and uncontrolled electrical discharge of the cardiac muscle fibers. ‘Ablations’ are small, therapeutic burns that cardiac electrophysiologists perform in the heart to create scars. These scars act as barriers to interrupt the irregular electrical currents. These procedures are performed via small catheters placed through veins and arteries in the groin.Atrial fibrillation is the irregular electrical discharge of the atria, or upper chambers of the heart, that can cause rapid beating of the ventricles, which are the lower chambers of the heart. The irregular beating can cause pooling of blood within the heart that can lead to clot formation. These clots can in turn dislodge from the heart and plug arteries in the brain or other parts of the body.
Patients with atrial fibrillation should be evaluated by their physicians to asses their risk for stokes. In the case where they are deemed to be high risk, warfarin (Coumadin) is necessary to protect the patient from clot formation. Besides thinning the blood, management also needs to focus on how to treat the symptoms of atrial fibrillation. This can be done through rate control (patient remains in atrial fibrillation, but medications are used to control high heart rates) or rhythm control (medications or ablation are used to attempt maintenance of normal heart rhythm). Both of these strategies are acceptable, and the decision of which one to follow is a clinical choice made between the patient and his/her physician.
Patients who do not respond to medical therapy may benefit from an ablation procedure. A group of French doctors, led by Dr. Michel Haïssaguerre, were the first to describe the electrical source in many cases of atrial fibrillation to be from the pulmonary veins in the left atrium. These are the blood vessels that return blood from the lungs back to the heart. By “ablating” within these veins, they were able to electrically isolate them from the heart and terminate atrial fibrillation successfully. This procedure is becoming progressively popular today. In some forms of atrial fibrillation, an ablative procedure can result in cure 70-80% of the time. In the remaining cases, repeat ablation may be necessary.
As this procedure continues to be perfected, debate has arisen as to which approach is best. Essentially, ablation can be targeted close to the connection between the pulmonary veins and the left atrium or further away from the veins. This latter strategy is referred to as wide area circumferential ablation (WACA). An ablation close to the veins usually results in shorter procedure time, but long-term benefits are being questioned.
Dr. Martel explains that, in fact, data in the medical literature increasingly is in favor of wide area ablation of the pulmonary veins to cure atrial fibrillation. In performing wider area ablation, other structures within the heart that have recently been found to contribute to atrial fibrillation can also be electrically isolated.
According to the AHA, atrial fibrillation affects more than two million people in the United States. Approximately 15% of strokes occur in people with this heart condition. The potential for developing atrial fibrillation increases with age. Three to five percent of people older than 65 years of age, and ten percent of those older than 80, have this condition.
