Cryo-Ablation for Treating Atrial Fibrillation
Cryo-Ablation - A Promising New Tool to Treat Atrial Fibrillation
The Electrophysiology Program at St. Luke's Hospital & Health Network is employing a new technique for atrial fibrillation that Darren M. Traub, DO, says is “a promising new technology” to help patients. St. Luke's is the first hospital in the Lehigh Valley region to offer “cryoballoon” ablation for patients with symptomatic atrial fibrillation.
Atrial fibrillation is the condition of irregular and rapid contractions in the atria, or upper chambers of the heart. Some patients with atrial fibrillation are asymptomatic, while others have fatigue, palpitations and shortness of breath. For many patients, atrial fibrillation can be a debilitating disease.
The traditional way of catheter ablation for treating atrial fibrillation, Dr. Traub explains, is with radio-frequency energy, delivered by a catheter to electrically isolate the pulmonary veins from the left atrium. Radio-frequency ablation uses heat to disable unwanted electrical impulses in the pulmonary veins that cause atrial fibrillation.
Freeze the Tissue so it does not Conduct Electrical Impulses
By contrast, the cryoballoon uses refrigerant inside the balloon to freeze the vein tissue. “Instead of cauterizing, we're freezing,” Dr. Traub says. Contact with the refrigerant draws heat out of the vein tissue, causing scarring and ending its ability to conduct electrical impulses. More importantly, Dr. Traub says, the balloon is inflated with liquid nitrous oxide to fill the inside of the vein, potentially enabling him to treat, or isolate, the entire vein at once. With radio-frequency ablation, doctors make a series of smaller lesions, requiring them to keep moving the head of the catheter.
Dr. Traub says the cryoballoon procedure is indicated for patients with symptomatic paroxysmal (which comes and goes on its own) atrial fibrillation who have not responded to treatment with medicine. The procedure involves making a small incision in a patient's groin area and threading the catheter through veins to the left atrium, where it connects to the pulmonary veins.
Study Shows Patients Free of Symptoms after One Year
The cryoballoon is made by Medtronic Inc. A 2010 study called STOP-AF, for Sustained Treatment of Paroxysmal Atrial Fibrillation, looked at the cases of 245 patients treated with the cryoballoon procedure. The lead research done at the Mayo Clinic in Rochester, Minnesota, found that 70 percent of the patients were free of atrial fibrillation symptoms after one year, compared to only seven percent of patients receiving drug therapy being symptom-free.
Dr. Traub says the ablation success rates are similar with cryoablation and radio-frequency ablation. The inherent differences in the energy source make the nature of the procedure and potential risks a bit different. He believes this is a promising technology that may prove quite beneficial to patients in the long run.
He adds that having the cryoablation machine at St. Luke's allows us to ablate many arrhythmias besides atrial fibrillation in patients as young as 14 years old that would not be amenable to catheter ablation with standard radiofrequency catheters. Dr. Traub and James P. Hummel, MD, the cardiac electrophysiologists at St. Luke's, strive to offer patients the forefront of ablation technology.