SAN FRANCISCO — Cryothermia ablation of atrial fibrillation restored sinus rhythm in more than 80% of 114 consecutive patients undergoing concomitant mitral valve surgery, Dr. Sacha P. Salzberg said at the annual meeting of the International Society for Minimally Invasive Cardiothoracic Surgery.
The investigators retrospectively reviewed patient charts and prospectively mailed a follow-up questionnaire to the referring doctors.
Patients were treated between January 2003 and June 2005 for paroxysmal atrial fibrillation in 55% and chronic atrial fibrillation in 45%. Degenerative mitral valve disease made up the bulk of valvular problems treated; 77% of patients underwent valve repair, and 23% had valve replacement, said Dr. Salzberg, whose research was performed at Mount Sinai Medical Center, New York.
Patients had a mean age of 66 years and had atrial fibrillation for a mean of almost 3 years before the cryosurgery. A total of 4% of patients died during surgery; 85% were discharged from the hospital with their sinus rhythm restored, said Dr. Salzberg and his associates.
Several lesion sets for ablation have been described for the left or right atria; the current study primarily created lesions on the left atria and included endocardial pulmonary vein isolation with a connecting lesion to the posterior aspect of the mitral valve annulus. In 8% of patients with documented atrial flutter, the physicians also made a right atrial set of lesions, said Dr. Salzberg, now of the University of Zurich.
A new pacemaker was needed in 8% of patients: six patients with sick sinus syndrome and three with third-degree heart block.
At 1-year follow-up, approximately 80% of patients remained in sinus rhythm. Use of anticoagulants and antiarrhythmic medications declined. There were no strokes and no complications related directly to the cryothermia ablation.
Cryothermia is a relatively new alternative to surgical ablation of atrial fibrillation, a well-accepted adjunct therapy in patients undergoing valvular surgery.
Although the Cox-Maze III procedure is considered the standard for surgical treatment of atrial fibrillation because of its high cure rate and long-term patency, the surgery is technically challenging, carries a high risk for renal problems, and is seldom performed, with only about 1,000 cases done in the past decade, said Dr. Salzberg.
Cryothermia should be applied routinely to patients undergoing mitral valve surgery with a history of atrial fibrillation, the investigators suggested.
The study's lead author was Dr. Farzan Filsoufi of Mount Sinai. Dr. Filsoufi and Dr. Salzberg have no financial association with the company that makes the cryothermia instrument, which applied a temperature of −160° C to create the atrial lesions.