Predictors of failure to cure atrial fibrillation with the mini-maze operation.

BACKGROUND: Maze-III is a complex surgical procedure designed to treat chronic atrial fibrillation. A reduction in the number of right and left atrial incisions could decrease the operative time. The aim of this study was to assess the results of a mini-maze operation and to define predictors of its failure. METHODS: Between 1995 and 2000, 72 patients (mean age 64 +/- 9 years) undergoing cardiac surgery had a concomitant mini-maze operation for symptomatic chronic atrial fibrillation. Three and 12 months post-operatively, heart rhythm and left atrial transport functions were assessed by electrophysiology, echocardiography, and magnetic resonance imaging. Multivariate analysis was performed to identify predictors of failure of the mini-maze operation. RESULTS: Operative mortality was 1.4% (1/72). Death during follow-up occurred in 5.6% of patients (4/71), in one due to chronic heart failure. After 1 year, 80% of patients (48/60) were either in sinus rhythm (n = 43; 72%) or had a pacemaker (n = 5; 8%) implanted due to sick sinus syndrome. Intermittent and chronic atrial fibrillation was found in 20% of patients (12/60). Preoperative duration of atrial fibrillation (p = 0.05), preoperative left atrial diameter (p = 0.001), preoperative right atrial diameter (p = 0.02), a reduced left ventricular ejection fraction (p = 0.03), an increased left ventricular end-diastolic diameter (p = 0.04), and the presence of mitral valve stenosis (p = 0.001) were found to be univariate predictors of failure of the mini-maze operation 1 year postoperatively. Multivariate analysis defined preoperative diagnosis of mitral valve stenosis (p = 0.005; OR 117.5), longer duration of preoperative atrial fibrillation (p = 0.01; OR 1.33), and increased preoperative left ventricular end-systolic diameter (p = 0.02; OR 1.2) as incremental independent risk factors for failure of the mini-maze operation to cure chronic atrial fibrillation. CONCLUSION: The mini-maze operation is a safe procedure with similar results to that of Cox's Maze-III operation. The less-invasive mini-maze operation could be applicable even to patients with severely reduced left ventricular function, in whom complex cardiac surgery has to be performed concomitantly as well as in those presenting severe comorbidities.

Long-term follow-up after the mini-maze procedure.

BACKGROUND: Atrial fibrillation (AF) is associated with significant morbidity and mortality. The standard to treat AF surgically is the Cox maze III procedure but owing to its complexity it is not performed on a regular basis. Meanwhile several maze variants have been developed but their long-term results are still not well known. METHODS: From November 1995 until May 2002 a mini-maze procedure was performed upon 77 patients aged 64 +/- 8.7 years with chronic symptomatic AF. Electrophysiological evaluation, magnetic resonance imaging, echocardiography and electrocardiographic evaluations were performed after 3 and 12 months. After a mean follow-up of 50 +/- 2.6 months a standard questionnaire was sent to all patients. RESULTS: Early and late mortality was 1.2% and 9.3% respectively. Actuarial survival was 91%, 90%, and 87% after 1, 3, and 5 years respectively. Left bundle branch block was an independent risk factor for late death (p = 0.02). Patients who were in sinus rhythm at follow-up had significantly better survival rate as compared with the patients still in AF. Seventy-one percent of patients were in sinus rhythm or paced by an atrial pacemaker. Predictors for restoration of sinus rhythm were absence of preoperative mitral insufficiency (p = 0.03) and larger left atrium (p = 0.04). The presence of preoperative tricuspid insufficiency (p = 0.03) and larger right atrium (p = 0.017) were predictors for postoperative pacemaker implantation. CONCLUSIONS: The mini-maze procedure can be carried out with satisfactory early and long-term results regarding mortality and restoration of sinus rhythm. Prophylactic implantation of biventricular pacemakers in patients with left bundle branch block may decrease late mortality. Every effort should be done to cure AF as it affects long-term survival.

Mitral annuloplasty in patients with ischemic versus dilated cardiomyopathy.

OBJECTIVE: Mitral regurgitation is a frequent finding in patients with end-stage cardiomyopathy predicting poor survival. Conventional treatment consists medical treatment or cardiac transplantation. However, despite severely decreased left ventricular function, mitral annuloplasty may improve survival and reduce the need for allografts. METHODS: From January 1996 to July 2002, 121 patients with severe end-stage dilated (DCM) or ischemic cardiomyopathy (ICM), mitral regurgitation > or =2, and left ventricular ejection fraction < or =30% underwent mitral valve annuloplasty using a flexible posterior ring. DCM was diagnosed in 30 patients (25%), whereas ICM was found in 91 patients (75%). Concomitant tricuspid valve repair was performed in 14 (46.6%) patients in the DCM, and in 11 (12%) in the ICM group (P=0.0001), coronary artery bypass grafting in three (10%) in the DCM, and in 78 patients (86%) in the ICM group (P<0.00001). The mean follow-up time was 567+/-74 days in the DCM and 793+/-63 days in the ICM group (ns). RESULTS: Early mortality was 6.6% (8/121), and was equal for both groups. Improvement in NYHA class (DCM 3.3+0.1-1.8+/-0.16; ICM from 3.2+0.04 to 1.7+/-0.07) were equal between groups after 1 year. Seventeen (15%) late deaths occurred during the follow-up period. There was no difference in the 2-year actuarial survival between groups (DCM/ICM 0.93/0.85). Risk factors for mitral reconstruction failure, defined as regurgitation > or =2 after 1 year, were preoperative NYHA IV in the DCM group (P=0.03), a preoperative posterior infarction (P=0.025), decreased left ventricular function (P=0.043), larger ring size (P=0.026) and preoperative renal failure (P=0.05) in the ICM group. Risk factors for death were larger ring size (P=0.02) and an increased LVEDD (P=0.027) in the DCM group and the postoperative use of IABP (P=0.002), renal failure (P=0.001), and a larger preoperative LVESD (P=0.035) in the ICM group. CONCLUSION: Mitral reconstruction with a posterior annuloplasty using a flexible ring is effective in patients with severely depressed left ventricle function and has an acceptable operative mortality. Mid-term results are superior to medical treatment alone and comparable to cardiac transplantation.