Atrial fibrillation is a heart rhythm disturbance that originates from heart chambers at the top of the heart, called the atria. The abnormal rhythm is fast and irregular and cannot adequately squeeze blood into the pumping chambers of the heart, the ventricles. According to the Cleveland Clinic, the goals for treatment of atrial fibrillation is to restore a normal rhythm, slow the heart rate, improve symptoms and decrease the risk of a blood clot forming from stagnant blood. Medications are usually used as the first line of therapy but are not always effective or tolerated. Pulmonary vein ablation, also known as pulmonary vein antrum isolation, or PVAI, is a form of therapy in which a small catheter threaded through the arm or leg vessels applies energy to create scarring around the pulmonary veins--small vessels entering the left atrium from the lungs--to control the atrial fibrillation. It is an increasingly used procedure but is not without complications.
Pulmonary Vein Stenosis
At one time, pulmonary vein stenosis--narrowing of a pulmonary vein blocking blood flow from the lungs to the heart--occurred frequently, according to a research report in the May 2006 issue of "Heart Rhythm." In recent years, scars are made around the pulmonary veins, rather than inside the vessels, which has significantly reduced the incidence of pulmonary vein stenosis to 1 percent of cases.
Stroke
Blood clots can form in the chambers of the heart as a result of atrial fibrillation as well as from the ablation procedure itself. Blood clots may travel to the brain and cause a stroke in about 0.5 percent of cases, reports Cleveland Clinic. The incidence of strokes as a complication from pulmonary vein ablation has decreased with the use of blood-thinning medications during and for two months after the procedure.
Heart Perforation
In up to 6 percent of cases, the ablation catheter inadvertently makes a hole, called a perforation, in the heart tissue, according to Virtual Medical Centre, an Australian medical information site. Often the hole will close on its own; however, bleeding through the hole into the space surrounding the heart may result in the heart unable to pump effectively, called cardiac tamponade. This is a life-threatening emergency that requires surgical intervention to drain the blood and sometimes repair the hole.
Damage to Esophagus
The Cleveland Clinic reports that damage to the esophagus, the feeding tube connecting the mouth to the stomach, can occur during a pulmonary vein ablation with an incidence of less than 1 percent. Sometimes the esophagus is injured by the ablation catheter; other times it is damaged by the probe, or scope, used in the throat to visualize the heart during the ablation. Surgical intervention may be necessary to repair the esophageal injury.
Persistent Atrial Fibrillation
Dr. D. Patel and colleagues reported in the October 2009 issue of "Heart Rhythm" that pulmonary vein ablation is unsuccessful in controlling atrial fibrillation in 31.5 percent of women and 22.5 percent of men who undergo the procedure. The difference in success rates is thought to be related to the longer duration of atrial fibrillation in women as well as anatomical differences. Success rates of ablation may improve with additional attempts.
References
- Cleveland Clinic: Pulmonary vein ablation
- "Heart Rhythm": How to select patients for atrial fibrillation ablation; H. Oral and F. Morady; May 2006
- Virtual Medical Centre: Cardiac Ablation for the treatment of Atrial Fibrillation
- "Heart Rhythm": Outcomes and complications of catheter ablation for atrial fibrillation in females; D. Patel et al; October 2009
