The Comparison Of Short-term Outcomes Of Radiofrequency Ablation For Atrial Fibrillation Between Two Surgical Procedures

BackgroundAtrial fibrillation(AF)is the most common clinical arrhythmia[1].The electrocardiogram(ECG)shows that the sinus rhythm electrical activity was replaced by the fast and complex atrial electrical activity,while the atrioventricular downlink rate was not very irregular and the speed is different and highly variable.The prevalence of atrial fibrillation among men and women over 35 years old was 0.74%and 0.72%[2],respectively,in China.In the patients with valvular disease,coronary heart disease,hypertension,hyperthyroidism and other pathophysiological conditions,atrial fibrillation may occur,which is particularly common in patients with valvular disease.In patients with mitral valve disease,the incidence of atrial fibrillation can be as high as 60%[3].Atrial fibrillation(AF)enable atrial systolic function loss,cause hemodynamic disorder and left atrial blood stasis followed by thrombosis,increasing the incidence of stroke,lowering the patients’ life expectancy.In patients with mitral valve disease combined with atrial fibrillation,ablation is essential for the treatment of atrial fibrillation in the same period[3,4].At present,the atrial fibrillation mechanism mainly includes the leading ring with multiple reentrant wave micro reentry,lung(cavity)vein muscle sleeves bureau stove trigger,imbalance of the autonomic nervous tension,renin-aldosterone system activation,hemodynamic overload,inflammatory/oxidative stress and atrial electrical/anatomical remodeling[5-7].However,the pathogenesis of atrial fibrillation in different patients may be different,the top of the left atrium and pulmonary vein were paid more and more attention in the pathogenesis of valvular atrial fibrillation.The atrial septum and right atrium of patients with atrial fibrillation may also be involved in the initiation and maintenance of atrial fibrillation[8].Park Hyung-Wook et al believed that the relationship between atrial fibrillation and autonomic nervous system,sympathetic and vagus nerve is the most common cause of paroxysmal atrial tachycardia and paroxysmal atrial fibrillation.The regulation of autonomic nervous system can inhibit the activation of stellate ganglion and reduce the occurrence of paroxysmal atrial tachycardia[9].But there is still no exact theory to explain all the mechanisms of the occurrence of atrial fibrillation,which may be due to the atrial fibrillation is a variety of mechanisms coexist and combined action.It is not entirely clear that the cause of atrial fibrillation,authors had proposed and created a lot of treatment measures to study the mechanism of formation of the atrial fibrillation,but still can not completely cure all kinds of atrial fibrillation.Since the advent of the Cox maze,has obtained good effect of treatment of atrial fibrillation.However,the traditional Cox maze operation is complex and has a lot of trauma and more complications,which limited the technique appliction.The Maze operation which represented with bipolar radiofrequency ablation has been proved to be an effective method for the treatment of chronic atrial fibrillation and drug refractory atrial fibrillation[10,11].In order to simplify the operation,many cardiac surgeons use various energy to ablate atrial tissue to replace the traditional cutting/stitching technique develop ablation linear to modify the original operation.Khargi etc[12]meta-analysis compared the various energy ablation(radiofrequency,microwave,frozen)with classic maze surgery for the treatment of atrial fibrillation,postoperative maintain sinus rhythm in ablation and classic maze group was 78.3%add 84.9%respectively(P = 0.03),but when control the type and duration of atrial fibrillation and the accompanying heart surgery,the difference was no longer have statistical significance(P=0.26).At present,there is no controversy over the application of ablation energy can replace the traditional method of cutting and sewing.But for atrial fibrillation in cardiac linear lesion question there is still no consistent conclusion[13-15]Domestic literature reports,compared with the treatment of isolated left atrial ablation,the effect of double atrial ablation is better[16].In recent years,the foreign reports have showed that the left atrial ablation plus simplified right atrial ablation,that is,the sinus and the narrow portion ablation,can obtain the similar efficiency as double atrial ablation,but less surgical trauma and atrial function loss,less postoperative complications,especially significantly reduce the risk of installed pacemakers.The current atrial fibrillation linear lesion formulation is still controversial,and the epidemiological characteristics of China valvular heart disease with atrial fibrillation is different with Europe and the United States and other developed countries,it is necessary to conduct relevant studies to develop simple,feasible,good effect linear lesion.ObjectiveTo study the methods of atrial fibrillation radiofrequency ablation for patients with valvular disease and atrial fibrillation,compare the efficiency and outcomes of technique of left atrial ablation plus simplified right atrial ablation with double atrial ablation,and to provide a guidance for making decision during operation.(The content of this research is from the national "twelfth five-year" science and technology support project.The project design and the ablation procedures referenced the method formulated by Professor MengXu of Beijing AnZhen Hospital.)Research objects,using instruments and methods1.Criteria:(1)a history of atrial fibrillation in line with the long-term sustained atrial fibrillation or persistent atrial fibrillation(AF)for more than 3 years;(2)both men and women,age in 20～75 years old(including);(3)no atrial thrombus,left atrial diameter(left ventricular long axis view)is less than or equal to 70 mm;(4)left ventricular end diastolic diameter(left ventricular long axis view)is less than or equal to 70 mm;(5)left ventricular ejection fraction(LVEF)is more than or equal to 50%;(6)Clinical diagnosis of rheumatoid heart valve disease and combine the atrial fibrillation.(7)All patients signed the informed consent.The exclusive criteria as following:the preoperative diagnosis is not in conformity with the inclusion criteria or need tricuspid valve replacement,can not cooperate with the requirements,who are participating in other clinical trials,patients with serious brain,heart,lung,kidney,liver or other important organ dysfunction,or the patient who was judged not suitable by other researchers.According to the above criteria,73 patients with rheumatic valvular disease complicated with atrial fibrillation were selected from January 2015 to June 2015,including 18 males and 55 females,aged from 24 to 75 years.The selected cases were randomly divided by the Microsoft Excel 2003 RAND()function into two groups:left atrial ablation plus simplified right atrial group(n=29),double atrial ablation group(n=44),.2、the main instruments:Atricure bipolar radiofrequency system or Medtronic bipolar radiofrequency ablation system,blood gas analyzer system,extracorporeal circulation machine,multi function monitor,ventilator,micro injection pump.3、research methods:After randomly assigned into two groups,all patients underwent a general clinical data comparison.Left atrial ablation plus simplified right atrial ablation group,29 cases,while double atrial ablation group 44 cases.Atrial fibrillation time in Left atrial ablation plus simplified right atrial ablation group was(43.52 ± 43,32)months,double atrial ablation group(32.02 ± 38.74)months,there was no statistical difference(P>0.05)between the two groups.There was no significant difference in age,gender,duration of atrial fibrillation,left atrial size,NYHA heart function classification,and left ventricular ejection fraction(P>0.05)in the two groups.Patients in both groups were carried out in the shallow hypothermia cardiopulmonary bypass.The double atrial ablation group’s ablation methods were as follows:cut of the ligament of Marshall,bilateral pulmonary vein isolation,resection of the left atrial appendage,clip and ablation the left atrial from the posterior wall to left atrium roof,set the following ablation line meanwhile:left superior pulmonary vein to the left atrium appendage ablation lines,interatrial sulcus incision connected right pulmonary veins to the mitral valve annulus ablation line;both sides of the pulmonary vein ablation connected lines,namely via the left atrium posterior wall form the right superior pulmonary vein to the left superior pulmonary vein and from right inferior pulmonary vein to the left inferior pulmonary vein ablation line.For right atrial ablation,an ablation line from coronary sinus to right atrial incision and to tricuspid annulus.Furthermore,set the following ablation lines in right atrial:from the right atrial incision to the direction of inferior vena cava(IVC)ablation lines;through the right atrial incision to the superior and inferior vena cava;from the right atrial incision to the right atrial appendage,and ablating the right atrial appendage.The ablation methods of left atrial ablation plus simplified right atrial ablation group were as same as double atrial ablation group,while the ablation line from the right atrial incision to inferior vena cava from right atrial incision superior vena cava from the right atrial iincision to right atrial appendage and the ablation line of the right atrial appendage ablation,were not performed.Only the line from coronary sinus to right incision and to tricuspid annulus was ablated.Each of the ablation lines was performed 3 times,while the left and right pulmonary vein isolation was ablated 5 times.After patients were administered into ICU,cardiac stimulant and diuretic were used preventing infection,maintaining water electrolyte balance,managing nutrition and other symptomatic support treatment,patients departed from ICU when the circulation and vital signs was stable.Patients in both groups received postoperative amiodarone through intravenous drip,and oral amiodarone when patients can eat after extubation.Continue to oral amiodarone three months totally after discharge,up to 200 mg,once per day.Observation and comparison of the contentThe clinical data,ablation time,cardiopulmonary bypass(CPB)time,arota cross clamp time,ICU stay time,ventilation time,postoperative sinus rhythm rate,mortality and follow-up results were compared between the two groups.Statistical analysisAll data analyses were performed using IBM SPSS Statistics 19 software(IBM Company Software,Inc).Continuous variables were expressed as mean ± SD or as median with range;they were compared using the t test for means of normally distributed continuous variables.Categorical variables were expressed as frequencies and percentages,with outcomes compared using chi-square test or the Fisher exact test.Multiple comparisons used LSD method to test the homogeneity of variance.The significance level was adjusted to P<0.05.ResultAll patients successfully underwent the operations,no perioperative death.Atrial fibrillation re-occurred in the left atrial ablation plus simplified right atrial ablation group was(43.52 + 43.32),the double atrial ablation group was(32.02 + 38.74),and there was no significant difference between the two groups(P>0.05).In left atrial ablation plus simplified right atrial ablation group,double valve replacement in 11 patients,mitral valve replacement in 17 patients,aortic valve replacement in 1 patients;and in double atrial ablation group,double valve replacement in 8 patients,mitral valve replacement in 36 patients;There was significant statistical difference between two groups in valve surgical procedures(P = 0.04),in Left atrial ablation plus simplified right atrial ablation group,double valve replacement was more than double atrial ablation group.Cardiopulmonary bypass(CPB)time,arota cross clamp time,ICU stay time,ventilation time in left atrial ablation plus simplified right atrial ablation group and double room group were 155.13 ± 32.00min and 144.42 ±37.64min(P=0.264).108.14 ±23.59 and 98.62 +23.34min(P=0.102),76.48 ±119.47h and 70.20±77.66h(P=0.786),23.95±22.29h and 25.23±27.96h(P=0.837)respectively.There were no significant differences in duration of operation,arota cross clamp time,days of hospitalization stay between the two groups(P>0.05).The difference of ablation time was statistically significant(P<0.05).Left atrial ablation plus simplified right atrial ablation group were shorter than the double atrial ablation group.Both group have a case of re-intubation after postoperative extubation due to hypoxia,the double atrial ablation group had a case of postoperative appear bradycardia,ECG showed heart rate was 37 beats/min.no permanent pacemaker was placed in the two groups.At the time of discharge,the restoration of sinus rhythm in the left atrial ablation plus simplified right atrial ablation group was 62.1%,and 72.7%in the double atrial ablation group,there was no significant difference between the two groups(x2=0.920,P=0.337).Patients of two groups were followed in 3 months after operation,the restoration of sinus rhythm was 69%in left atrial ablation plus simplified right atrial ablation group,and 76.2%in the double atrial ablation group,the difference was not statistically significant(x2=0.627,P=0.429).Follow up in 6 months after operation,the restoration of sinus rhythm was 79.3%in left atrial ablation plus simplified right atrial ablation group,and 75%in the double atrial ablation group,the difference was not statistically significant(x2=0.182,P=0.670).ConclusionLeft atrial ablation plus simplified right atrial ablation can achieve the similar sinus rhythm rate when compared with the double atrial ablation,but the former reduced the number of linear lesion,simplified the procedure and shorten the ablation time.