Spontaneous cardioversion and mitral valve repair: A role for surgical cardioversion (Cox-maze)?

OBJECTIVE: The objectives of this study are to describe: (1) Theincidence of change in pre-operative rhythm (cardioversion) with mitralvalve repair early and at 1 year's review after surgery (late). (2) Thecharacteristics of those patients who remain in atrial fibrillation (AF) orsinus rhythm (SR) at late follow up. (3) The characteristics of thosepatients whose rhythm is seen to change (cardiovert) from SR to AF, or AFto SR and to remain so at 1 year. In this way it is hoped to more clearlydefine those patients who would benefit from the combination of mitralvalve repair and surgical cardioversion (Cox-maze procedure). METHODS:Retrospective study was made of the case notes of all patients undergoingmitral repair at our hospital during the 3 years between January 1st, 1991and December 31st, 1993. Early (hospital discharge) and late (1 year) postoperative e.c.g. rhythm was compared to pre-operative e.c.g. rhythm. Thestudy explored the association of cardioversion with pre-operative rhythm,patient age, aetiology of mitral valve lesion (mitral regurgitation orstenosis) and echo cardiographic estimations of left atrial size and leftventricular dimensions. RESULTS: Patients (89) underwent repair with a 30day mortality of 2.2% (2 of 89). Of these, 55 were male with an average ageof 65 +/- 12 years. Regurgitation was the valvular lesion in 93% and 18%were associated with coronary artery disease, 48 (55%) were in SR beforesurgery. Both deaths occurred in patients with AF as a pre- operativerhythm. Of the 39 survivors originally in AF, only one was of recent onset( < 6 months). The frequency of an enlarged left atrium (> or = 5.0cm) was significantly greater in those with AF compared to SR (P