Radiofrequency Modified Maze Procedure Combined With Valvular Surgery For Rheumatic Atrial Fibrillation

1. Efficiency of Radiofrequency Modified Maze Procedure Combined with Valvular Surgery for Rheumatic Atrial Fibrillation:A Prospective and Randomized StudyObjective:The aim of this randomized, prospective trial was to evaluate the effectiveness of intra-operative radiofrequency cooled tip ablation in a modified MAZE procedure during mitral valve surgery. In a randomized fashion we evaluated the efficacy of patients undergoing a modified MAZE procedure, in addition to mitral valve replacement, in patients with long-term persistent atrial fibrillation and rheumatic heart disease. Is there a rationale for the addition of anti-arrhythmic surgery in patients undergoing open heart surgery?MethodsBetween March2008and May2010,160patients were randomized to two groups:radiofrequency group (n=80) and amiodarone group (n=80). Patients from radiofrequency group were underwent valvular surgery concomitant with radiofrequency modified maze III procedure. The amiodarone group patients underwent valvular surgery alone and received amiodarone to control cardiac arrhythmia for12months after surgery. All patients were scheduled followed up before discharge and at1st,3rd,6th and12th postoperative months. The data about rhythms, strokes were collected after clinical evaluation, electrocardiogram,24-hr Holter-electrocardiographic and echocardiogram. Atrial transport function was evaluated during the last follow-up using echocardiogram with Doppler analysis of mitral and tricuspid flows. ResultsAll patients have successfully completed the surgery and the1-year follow-up. Patients in radiofrequency group and patients in amiodarone group did not differ in regard to age, sex distribution, preoperative duration of atrial fibrillation, left atrial diameter in echocardiography, left ventricle end-diastolic diameter and pre-operative left ventricular ejection fraction.Radiofrequency group had80cases, including30males and50females, mean age was53.8±10.9years old, the average atrial fibrillation duration preoperative was29.9±19.7months, and the left atrium diameter was53.3±6.7mm. Among them,56underwent mitral valve replacement surgery,24cases underwent bivalve replacement surgery (mitral and aortic valve replacement, and34cases combined with tricuspid valvuloplasty surgery. The amiodarone group had80cases,33males and47females mean age was54.1±10.1years, the average atrial fibrillation duration preoperative was32.2±26.7months, and the preoperative left atrium diameter was51.9±10.0mm, and49underwent mitral valve replacement surgery,31underwent bivalve replacement surgery and38cases combined with tricuspid valvuloplasty surgery.The extracorporeal circulation time and the aortic clamping time increased obviously in the radiofrequency group compared with the amiodarone group (p<0.05). No perioperative death occurred in both groups. In the radiofrequency group patients, one had a reoperation for bleeding; two patients had a permanent pacemaker implantation for degree Ⅲatrioventricular blockage, one IABP implantation for low cardiac output, one sudden death4months after surgery in radiofrequency group. No stroke was presented during the follow-up time in both groups, there is no significant difference between two groups considering the complications and the mortality during the perioperative period and the follow-up time (P>0.05).The sinus rhythm restoration rate of the radiofrequency group were much better than the amiodarone group at hospital discharge,1month,3months,6months and lyear follow-up time postoperative (55%VS.25%,57.5%VS.27.5%,62.5%VS.23.8%,70%VS.22.5%, and70%VS.23.8%, P<0.001respectively).There were significant reduce of the left ventricle end-diastolic diameter in both groups after surgery (P<0.05), but there was no statistical significance in comparison of two groups (P>0.05). The postoperative left atrial diameter reduced obviously in both groups (P<0.05), and it was more obviously in the radiofrequency group than the amiodarone group.At the latest follow up, the atrial contractile function was detected by the Doppler echocardiography in the patients who were returned to the sinus rhythms. The results showed that there was no significant difference in the left and right atrial contractile function restoration rate between the radiofrequency and the amiodarone groups (P>0.05).The radiofrequency group patients were assigned to sinus rhythm restoration group and atrial fibrillation recurrence group according to the results of the6-months follow-up. The atrial fibrillation recurrence group had significant higher left atrial diameter than the sinus rhythm restoration group (p<0.001), whereas there was no difference in regard to age, preoperative duration of atrial fibrillation, left atrial size in echocardiography, and pre-operative left ventricular ejection fraction.Among age, left atrial diameter, preoperative atrial fibrillation duration, Left ventricular ejection fraction, aortic cross-clamp duration and whether combined with tricuspid plastic surgery, multiple logistic regression analysis failed to show an independent risk factor for the sinus rhythm restoration after the radiofrequency modified MAZE III procedure.ConclusionsA modified MAZE operation using cooled-tip radiofrequency ablation can be safely combined with rheumatic valve surgery and is highly effective in restoring sinus rhythm. Sinus rhythm cardioversion is not equivalent to recovery of atrial contraction. The radiofrequency modified Maze procedure has no adverse effects on the recovery of atrial function restoration. This study failed to show an independent risk factor for the sinus rhythm restoration after the procedure. 2. Impact of matrix metalloproteinase-2expression on long-term outcome following radiofrequency modified maze procedureBackgroundWe aimed to study the expression of matrix metalloproteinase-2(MMP-2) and its specific tissue inhibitors of metalloproteinases (TIMP-2) in left atrial appendage of patients with rheumatic valvular disease and persistent atrial fibrillation treated with radiofrequency modified maze procedure and assesses their influence on the efficacy of radiofrequency modified maze procedure.Methods56patients with sinus rhythm maintained were compared to24patients with AF recurred at6months postoperative. The mRNA and protein expression were determined by RT-PCR and Western blotting. Picrosirius red was used to stain collagen.ResultsAt6month's follow-up, AF recurred in24of the80AF patients. The mRNA and protein expression of MMP-2and type Ⅰ collagen volume fraction (CVF-Ⅰ) in AF recurred group were increased significantly than in the SR maintained group (p<0.001). While, the mRNA and protein expression of TIMP-2and the type Ⅲ collagen volume fraction did not reveal any difference between the2groups (p>0.05). The mRNA and protein expression of MMP-2were positively correlated with CVF-Ⅰ (r=0.575, p<0.001; r=0.637, p<0.001, respectively) and left atrial dimension (r=0.465, P=0.003; r=0.571, p<0.001, respectively).ConclusionThe expression of MMP-2was positively correlated with the CVF-Ⅰ in left atrial appendage and associated with the AF recurrence after radiofrequency modified maze procedure in patients with rheumatic valve disease.