Effect of mitral valve repair/replacement surgery on atrial arrhythmia behavior

BACKGROUND AND AIMS OF THE STUDY: Few data have been published on the effects of mitral valve surgery on atrial rhythm. The study aims were to determine the effects of surgery on: (i) persistence of atrial fibrillation (AF); (ii) measures of left atrial and ventricular dimensions; and (iii) ECG P-wave duration. METHODS: A retrospective case-note review of 92 patients with chronic mitral regurgitation was undertaken. Variables determined included prevalence and duration of AF; incidence of new-onset or persistence of AF after surgery; rhythm changes in relation to age, gender, left atrial and ventricular dimensions and function, anti-arrhythmic drug usage and ECG P-wave duration in sinus rhythm prior to surgery. RESULTS: Only 4/47 (8.5%) patients with any history of AF before surgery were in sinus rhythm at six months after surgery. All 28 patients with persistent AF for >12 months and 41/45 (91%) in sinus rhythm before surgery retained these rhythms after surgery. The left atrial dimension was decreased after surgery, in the whole group (51.3 +/- 9.0 versus 48.4 +/- 9.5 mm; p = 0.011) and in the subgroup in sinus rhythm, but not in the subgroup in AF. The left ventricular end-diastolic dimension decreased in the group as a whole (60.6 +/- 6.2 versus 53.0 +/- 8.7 mm; p = 0.0001) and in both subgroups after surgery. In 24 patients with 12- lead ECGs in sinus rhythm before and three months after surgery, P-wave duration remained unchanged. However, this measure decreased in the 18 patients in sinus rhythm consistently, but increased in the six patients continuing to have paroxysmal AF after surgery. CONCLUSION: Mitral valve surgery alone restored sinus rhythm in only 8.5% of patients with any previous history of AF. Concomitant anti-arrhythmic procedures should be considered for all patients with AF who undergo mitral valve surgery.