Patients
The retrospective study was approved by the Ethics Committee of Changhai Hospital affiliated to Naval Military Medical University (No. 20220216; February 16, 2022). All patients have been given an opt-out participant information and signed informed consent for treatment. 126 patients with AFMR who had undergone MV repair and a concurrent maze procedure (the surgical group) in the department of cardiovascular surgery and 66 patients who had undergone catheter ablation surgery (the ablation group) in the department of cardiology were eligible for inclusion between January 2012 and December 2015. All of the patients were diagnosed with chronic HF symptoms, New York Heart Association (NYHA) functional class II or higher, persistent or long-standing persistent AF, moderate to severe MR, and left ventricular ejection fraction (LVEF) ≥ 50%. Patients were excluded if they had the following: organic MR (flail leaflet, leaflet prolapsed, chordae ruptured or elongated, annular calcification, leaflet thickening, rheumatic heart disease, leaflet perforation, cleft leaflet, parachute MV, ischemic heart disease, or cardiomyopathy), LVEF < 50%, coronary artery disease (CAD), left atrial thrombus, and paroxysmal AF. The guidelines define long-standing persistent AF as continuous AF of > 12 months' duration when it is decided to adopt a rhythm control strategy [7]. Persistent AF is defined as AF continuously sustained beyond 7 days, including episodes terminated by cardioversion (drugs or electrical cardioversion) after 7 days. Clinical and demographic information for every patient was gathered retroactively.
Surgical technique
The patients in the surgical group underwent median sternotomy. Cardiopulmonary bypass (CPB) was established by ascending aortic cannulation and bicaval venous return. The maze procedure was performed using bipolar radio frequency ablation (Atricure, Inc, Cincinnati, Ohio) with the heart arrested. The LA appendage was removed after the right Pulmonary vein (PV) were isolated, and then the left PV were ablated in a similar fashion. Each application was repeated three times. Two ablation lines were created from the right inferior PV to the left inferior PV and from the right superior PV to the left superior PV to create connecting lesions. The box lesion to the mitral annulus was created with mono-polar device with a view to reducing recurrence of AF. The right atrial maze procedures were accomplished by creating an ablation line from the superior vena cava to the inferior vena cava, an ablation line from the right atrial appendage to the atrioventricular groove, and a caudal right atrial ablation line from the atrioventricular groove to the inter atrial septum. The MV was exposed through an inter-atrial groove incision. After sizing of the intercommissural distance and anterior MV size, an annuloplasty ring (Carpentier-Edwards Physio Ring, Edwards Life Sciences, Irvine, USA; Duran Ancore Annuloplasty, Medtronic, Minneapolis, USA) was implanted. If there was a large gap between the anterior mitral leaflet and the posterior mitral leaflet owing to severe posterior leaflet tenting, posterior leaflet augmentation using autologous pericardium was performed. If moderate-severe tricuspid Regurgitation (TR) existed, the concomitant tricuspid annuloplasty (TAP) procedure was performed via DeVega technique or implanting an annuloplasty ring (BalMedic annuloplasty, BalMedic, Beijing, China).
Catheter ablation procedure
All patients underwent pulmonary vein electrical isolation, left atrial fragmentation potential ablation, mitral annulus isthmus linear ablation, left atrium top linear ablation, and cavo-tricuspid isthmus ablation. The ablation endpoint was both persistent PV isolation and no AF with repeat incremental infusion of up to 20 ug/min of isoproterenol, as previously described [4].
Echocardiographic analysis
All patients had a transthoracic echocardiogram (TTE) (Vivid E9, General Electric Company, Boston, USA) perioperatively and in follow-up. To assess the result of MV repair, patients in the surgical group had an intraoperative transesophageal echocardiogram (TEE). The severity of MR and TR were defined using an assessment of the color Doppler-derived jet area, the effective regurgitant orifice area using the proximal isovelocity surface area method. The morphology and dimensions of the LA and LV were also measured [8]. The LA volume, left ventricular end-diastolic dimension (LVEDD), left ventricular end-systolic dimension (LVESD), and interventricular septum thickness (IVST) were measured according to guidelines [9]. All echocardiograms were interpreted by one experienced cardiologists with level III training, and the echocardiography readers were not blinded to the patient data.
Patient follow-up
Patients were routinely treated with anti-arrhythmic medications. Anti-arrhythmic medications were typically discontinued at 6 to 12 weeks if patients had paroxysmal AF and at 6 months if they had persistent AF, but were continued beyond this point in selected patients based on doctor and/or patient preference even in the absence of an arrhythmia event. The patients who were implanted with an annuloplasty ring were treated with warfarin for at least 3 months in the surgical group. Warfarin was definitely given to all patients who stayed in AF but was stopped 6 months later if they reverted to sinus rhythm.
All preoperative and postoperative data, including clinical, electrocardiogram, and echocardiographic findings, were obtained from the institutional database. Follow-up information was collected through a telephone interview with surviving patients or an outpatient appointment. All patients' follow-up lasted 7.98 2.01 years and was completed 100% of the time. The observed indicators included the overall mortality, the readmission for HF, the MR degree, the recurrence of AF, the cardiac remodeling values assessed by echocardiography, and the rhythm assessed by Holter electrocardiogram in the follow-up. Electrocardiogram and echocardiographic follow-up findings were obtained by querying the institutional database.
Statistical analysis
Statistical analysis was performed with the Statistical Package for Social Sciences 19.0 (SPSS, Inc., Chicago, IL, USA). All continuous variables were expressed as mean ± standard deviation and were tested for normality. If the continuous variables conform the normal distribution, the Student t-test was used for comparison; otherwise, the Wilcoxon rank-sum test was used for comparison. Categorical variables were expressed as percentages and compared according to the Pearson chi-square test, Continuity corrected chi-square test or Fisher exact test. The univariable and multivariable analysis were estimated by the Logistic regression analysis. For all time-to-event analyses, rates were estimated by the method of Kaplan–Meier and compared by the log-rank test. A P < 0.05 was considered statistically significant. The power calculation made to minimal participant number was 0.9998.