Atrial Fibrillation (cont.)
Daniel Lee Kulick, MD, FACC, FSCAI
Dr. Kulick received his undergraduate and medical degrees from the University of Southern California, School of Medicine. He performed his residency in internal medicine at the Harbor-University of California Los Angeles Medical Center and a fellowship in the section of cardiology at the Los Angeles County-University of Southern California Medical Center. He is board certified in Internal Medicine and Cardiology.
Charles Patrick Davis, MD, PhD
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
In this Article
- Atrial fibrillation facts
- What is atrial fibrillation?
- What causes atrial fibrillation?
- What are the symptoms of atrial fibrillation?
- What are the complications of atrial fibrillation?
- What are the risk factors for developing atrial fibrillation?
- How is atrial fibrillation diagnosed?
- What is the treatment for atrial fibrillation?
- Reversing the risk factors that cause atrial fibrillation
- Slowing the heart rate with medications
- Anticoagulation to prevent blood clots and strokes
- Converting atrial fibrillation to a normal rhythm
- Procedures for treating and preventing atrial fibrillation
- What is new in atrial fibrillation?
- Atrial Fibrillation - Slideshow
- Take the Atrial Fibrillation Quiz!
- Heart Disease - Slideshow
- Atrial Fibrillation A-Fib FAQs
- Find a local Cardiologist in your town
What is new in atrial fibrillation?
Pulmonary vein isolation
The four pulmonary veins are blood vessels that carry oxygen-rich blood from the lungs to the left atrium. There is a narrow band of muscle cells that surrounds the openings of the pulmonary veins where they enter the left atrium. This band of muscle cells may begin to actively discharge electrically, and this discharge may initiate atrial fibrillation. During pulmonary vein isolation (PVI), the band of muscle cells is destroyed by energy applied through a catheter. This effectively blocks the electrical discharges from crossing over from the band to the left atrium and hence, prevents atrial fibrillation.
Procedure. Before PVI, the doctor performs a history and physical examination, an EKG, a 24-hour Holter monitor, and a transesophageal echocardiogram to exclude blood clots in the atria, and, sometimes, a CAT scan of the chest. The doctor also may ask the patient to stop certain medications, particularly blood thinners such as aspirin, clopidogrel (Plavix), or warfarin, several days before the procedure. The doctor may check a blood prothrombin time and INR level to make sure that blood clotting is adequate for the procedure.
PVI is usually performed under deep conscious sedation (but occasionally general anesthesia) in a cardiac electrophysiology laboratory and takes 3 to 6 hours. Several catheters are inserted through large veins (in the neck, arm, or groin) and fed into the left atrium under X-ray (fluoroscopy) guidance. One of the catheters is equipped with an ultrasound transducer that allows the doctor to view the structures inside the heart during the procedure. The junction of the pulmonary veins with the left atrium is identified, and energy is then applied through another catheter to this area. This results in the destruction of the band of muscle cells and their replacement by a scar. This process is repeated at the opening of each of the four pulmonary veins into the left atrium.
Course postpulmonary vein isolation. After PVI, patients remain in the hospital telemetry unit so that the heart's rhythm can be monitored.
Many patients will experience atrial fibrillation and palpitations (irregular heart beat) while in the hospital and during the first 2 or 3 months following PVI. Therefore, they are given medications such as amiodarone to prevent episodes of atrial fibrillation and anticoagulation with medications such as warfarin to prevent strokes. The palpitations and episodes of atrial fibrillation gradually decrease. By 3 months after the procedure, the majority of patients will have a normal rhythm, and the doctor may stop warfarin and amiodarone.
Patients usually will have an EKG and a CAT scan of the chest 3 months after PVI. The CAT scan is done to make sure that there is no narrowing of the pulmonary veins (pulmonary vein stenosis) due to the scarring.
Effectiveness of pulmonary vein isolation. PVI in the U.S. is a relatively new procedure. When performed by experienced doctors, PVI can be expected to prevent atrial fibrillation in 70% to 80% of patients during the first year. Some patients may need additional PVI procedures to prevent further atrial fibrillation episodes. Because this procedure is new, it is difficult to know whether successfully-treated patients will continue in a normal rhythm for a prolonged period of time.
Risks of pulmonary vein isolation. When performed by doctors experienced in PVI, the procedure is safe. The risks of pulmonary vein isolation include cardiac tamponade (bleeding into the pericardium, the sac surrounding the heart), narrowing of the openings of the pulmonary veins, injury to the phrenic nerve that controls the function of the diaphragm, injury to peripheral blood vessels, and, in rare cases, death.
In the early years of PVI, doctors were trying to destroy the tissues inside the pulmonary veins. This led to narrowing (due to scarring) of the pulmonary veins which, in turn, led to pulmonary hypertension, a condition in which the blood pressure in the pulmonary veins and arteries increases. Pulmonary hypertension is a serious condition that can lead to heart failure and even death. Doctors no longer try to destroy tissue inside the pulmonary veins. Instead, they try to destroy the tissues only at the junction of the pulmonary veins and the atria. The current technique is not only safer but is more effective and simpler.
Candidates for pulmonary vein isolation. Generally, good candidates for PVI include:
- Patients with chronic sustained atrial fibrillation or paroxysmal (intermittent) atrial fibrillation
- Patients who develop recurrent atrial fibrillation while on medications
- Patients with recurrent atrial fibrillation who cannot tolerate the side effects of long-term medications
- Patients with recurrent atrial fibrillation who do not wish to continue taking long-term medications or anticoagulation
Wann, Samuel L., et al. "2011 ACCF/AHA/HRS focused update on the management of patients with atrial fibrillation (Updating the 2006 Guideline): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines." Journal of the American College of Cardiology 57.2 (2011): 223-242.
Previous contributing author: Dennis Lee, MD
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