Long-term results after ablation for long-standing atrial fibrillation concomitant to surgery for organic heart disease: Is microwave energy reliable?

Abstract

Microwave ablation has been reported as efficient for the surgical treatment of long-standing atrial fibrillation. However, the influence of ablation lesions on long-term results is not known. From August of 2000 to November of 2003, 41 patients underwent a left atrial endocardial microwave ablation procedure after a Cox-Maze-like lesion set for long-standing atrial fibrillation concomitant to surgery for valvular or coronary artery disease. Mitral valve surgery alone or combined was performed in 31 cases (75.6%). The mean diameter of the left atrium was 7.19 +/- 1.44 cm. The mean duration of preoperative atrial fibrillation was 4.7 +/- 3.6 years. Patient follow-up was conducted by means of direct clinical examination, electrocardiography, and transthoracic echocardiography. The mean follow-up was 5.37 +/- 0.91 years. Patient follow-up was achieved in 82% of cases (n = 28). Seven patients (17%) died during follow-up. Stroke was the cause of death in 1 patient with persistence of atrial fibrillation. Major complications occurred in 4 (14.3%) of the patients that were related to the persistence of atrial fibrillation. At 5 years follow-up, 39.3% of patients (11/28) were in sinus rhythm. Seventeen patients (60.7%) were in New York Heart Association classes I and II, and 11 patients (39.3%) were in New York Heart Association class III at the time of follow-up. In our experience, left atrial endocardial microwave ablation for long-standing atrial fibrillation after a Cox-Maze-like ablation lesion set during surgery for organic heart disease is not a reliable method of achieving long-term conversion to sinus rhythm.