Application Of Electrophysiological Mapping And Atrial Fibrillation Induction In Cox-Maze Surgery For Valvular Atrial Fibrillation

ObjectiveTo observe the perioperative,6 months’ and 1 year’s safety and effectiveness of electrophysiological mapping assisted Cox maze Ⅳsurgery(Electrophysio-Maze),and to study the correlation between the integrity of main ablation lines and the inducibility of atrial fibrillation,as well as the correlation between the long-run atrial fibrillation recurrence with the integrity of main ablation lines and the inducibility of atrial fibrillation during Cox-Maze procedure.MethodsInpatients with aortic valve or mitral valve disease and persistent atrial fibrillation in the department of cardiac surgery of the Second Xiangya Hospital of Central South University will be prospectively and continuously enrolled into the Electrophysio-Maze group and the control group respectively.The maze Ⅳ procedure was performed during the valve operation in the Electrophysio-Maze group,and then the integrity of left atrial “box” ablation line,mitral isthmus ablation line and tricuspid valvular annulus ablation line was measured with a 10-pole electrophysiological catheter which was connected to a 64-channel electrophysiological recording system.Whether to conduct supplementary ablation in incomplete tricuspid valvular annulus ablation lines will depend on the stability of the patient’s clinical condition independently judged by the operator.However,for the sake of safety,incomplete ablation lines in "box" area or mitral annular isthmus will not be supplemented.Atrial fibrillation induction procedure was performed before and after maze Ⅳ.Amiodarone hydrochloride will be administered for 3 months in every patients.24-hour ambulatory electrocardiogram and color Doppler echocardiography will be performed after 6 months in both groups.In Electrophysio-Maze group,24-hour ambulatory electrocardiogram will be performed again after 1 year.Follow up and treatment were performed by doctors independent of the principal investigator.Recurrence of atrial fibrillation is defined as atrial fibrillation or atrial flutter lasting more than 30 seconds.Results:42 patients were enrolled into the Electrophysio-Maze group and 38 patients were enrolled into the control group.The baseline data of the two groups were balanced.Compared with the control group,the bypass time and aorta clamp time were longer,but the hospital stay was shorter in Electrophysio-Maze group.In Electrophysio-Maze group,one patient was hospitalized again due to chest wound infection and recovered after debridement,but there was no significant difference in main safety indicators such as stroke and death between the two groups.In Electrophysio-Maze group,atrial fibrillation was induced in 88.1%(37/42)of patients before operation and in 14.3%(6/42)of patients after operation.The rate of "box" ablation line integrity immediately after Cox-Maze Ⅳ was 100%,and the rate of mitral isthmus ablation line disintegrity or tricuspid annulus ablation line disintegrity in maze groups was 23.8%(10/42).Counting two cases of supplementary ablation,the overall rate of ablation line disintegrity was 19.0%(8/42).There was significant correlation between disintegrity of main ablation lines with atrial fibrillation inducibility immediately after Cox maze Ⅳ.All patients took amiodarone hydrochloride for 3 months.There was no death,stroke or pacemaker implantation caused by delayed atrioventricular block in both groups during 6 months’ follow-up.Compared with the control group,the Electrophysio-Maze group’s diameters of left atrium,right atrium,left ventricle and right ventricle decreased,the left ventricular ejection fraction increased,and the rate of free of atrial fibrillation increased(88.1% vs 13.2%,P<0.001)after 6 months.In Electro Physio-Maze group,there was still no death,stroke or pacemaker implantation after 1 year,and except three patients who have not accepted24-hour ambulatory electrocardiogram examination,the rate of free of atrial fibrillation 1 year after surgery in remained 39 cases is 89.7%.There was significant correlation between the recurrence of atrial fibrillation 6 months and 1 year after surgery with the disintegrity of main ablation lines and the atrial fibrillation inducibility in Cox-Maze procedure.ConclusionElectrophysiological mapping assisted Cox-Maze procedure has advantages in promoting better changes in cardiac remodeling and higher remission rate of atrial fibrillation after 6 months,and in Electro Physio-Maze group,the remission rate of atrial fibrillation after 1year is no less than that of 6 months’.Electrophysiological mapping in Cox-Maze can find out incomplete valvular annulus ablation lines and guide assisted ablation.Because there was significant correlation between the recurrence of atrial fibrillation 6 months and 1 year after surgery with the disintegrity of main ablation lines,there might be possibility for the cure of recurrence of atrial fibrillation by supplementary catheter or hybrid ablation in the future.