Late onset of atrial fibrillation in patients undergoing mitral valve repair for type II dysfunction.

BACKGROUND: There are few reports regarding factors related to late-onset of atrial fibrillation (Af) after mitral valve repair, which can compromise long-term outcome. We analyzed the risk factors for late Af after mitral valve repair.

METHODS AND RESULTS: Between 2001 and 2015, 318 patients (214 males; median, 57.7 years) underwent mitral valve repair for degenerative mitral insufficiency (MI) without concomitant aortic valve disease in our institute. Patients with a history of paroxysmal or chronic Af preoperatively were excluded. Serial follow-up echocardiography was used to evaluate cardiac function. The follow-up rate was 99%. The mean follow-up period was 6.0±4.1 years. There was no early death and there were nine late deaths. A total of 29 (9.1%) patients developed late Af. Freedom from late Af was 94.0% at 5 years and 82.9% at 10 years. Small ring annuloplasty, left atrial diameter, and pressure half time, which were measured at follow-up echocardiography, were considered as significant (p<0.05) risk factors for late Af. Patients who had late Af developed recurrent MI more frequently than those who did not (p<0.05).

CONCLUSIONS: Remodeling of the atrium caused by functional mitral stenosis is important for late Af, as well as recurrent MI. To prevent these problems, avoiding selection of a small ring at primary mitral repair for type II dysfunction and durable repair are required.