Cardiac Electrophysiological Study Prior To And Following Transcatheter Closure Of Ventricular Septal Defects

Part one:Study on the Impact of Cardiac Conductin Function following Transcatheter Closure of Ventricular Septal DefectsBackground and objective:Ventricular septal defect(VSD) accounts for about20%-30%of congenital heart disease.Transcatheter closure of VSDs has experienced a stage of rapid development during the past decade owing to the improvement and nationalization of the VSD occluder in China.The cases of transcatheter closure of VSDs had increased dramatically in the recent few years.however the complication of atrioventricular block(AVB) has to be taken into consideration and has become one of the safety disputes.The incidence of AVB reported in literature was1.9%-31.6%.In this study the impact of transcatheter closure of VSDs on the cardiac conduction dunction was evaluated by invasive cardiac electrophysiological (EPS) methods,seeking high rick factor of post-closure arrhythmia especially AVB.Material and methods:From March2011to March2012,66patients underwent transcather closure of VSD in Zhongshan Hospital affiliated to Fudan University.According to history and left ventricular angiography,patients were confirmed as follows:47cases of perimembranous VSDs.5cases of muscular VSDs,7cases of intracristal VSDs,5cases of residual shunts after VSD surgical repair,2cases of ventricular septal rupture after myocardial infarction.All patients were devided into two groups which were PMVSD group and nonPMVSD group.Body surface electrocardiogram(ECG) and His bundle electogram(HBE) were taken pre-and post-implatation of occluders which were made in China.PR interval、QRS complex interval.A-H interval,His duration and H-V interval were measured.Surface ECG was performed at the24th hour,48th hour,lst month,3nd month and6th month after the procedure for each patient who had successful closure of VSD.Results:The defects were successfully closed in59/66patients (success rate of89.3%).No significant change for PR interval on surface ECG was observed before and after closure (P=0.091). But the QRS complex interval showed a significant prolongation(P=0.003).As for the invasive EPS parameters,A-H interval、His duration and H-V interval showed the similar significant difference pre-and post-procedure,which were82.4±16.9vs88.8±19.4ms(P=0.000)、19.6±2.5vs20.5±2.5ms(P=0.008).45.3±7.0ms vs48.7±7.8ms(P=0.000) respectively.But only H-V prolongation has significant difference in PMVSD group compared with nonPMVSD group.Follow-up duration after closure was1-12months,there were23cases(39.7%) of new-onset of arrhythmia including:3cases of I degree atrioventricular block(AVB),l case of left anterior hemiblock(LAH),l case of complete left bundle-branch block(CLBBB),7cases of complete right bundle-branch block(CRBBB),5cases of incomplete right bundle-branch block(IRBBB),l cases of I degree AVB combined with CRBBB,3cases of paroxysmal accelerated atrioventricular junction rhythm.1case of atrial premature beat,l cases of atrioventricular junction premature beat.Except1case sustained paroxysmal accelerated atrioventricular junction rhythm1year after closure,other22cases of arrhythmia recovered.No occluder displacement、high degree AVB、hemolysis、valve and chordate tendineae injury and other serious complications related to electrophysiological study were noted.H-V interval prolongation more than3.5ms can be used as a predictor of postoperative conduction disturbance with sensitivity of71.4%, specificity of70.1%and odds ratio (OR) of6.14. As for PMVSD group, H-V interval prolongation more than2.5ms can be used as a predictor with sensitivity of77.8%, specificity of66.7%and OR of7.0.Conclusion:Transcatheter closure of VSDs with occluder made in China is a safe and effective option with limited complications.The impact on cardiac conduction system lies mainly in the conductive bundle beneath the atrioventricular node.Transient injury of cardiac conduction system is a common complication.H-V interval prolongation if more than3.5ms can be used as a predictor of postoperative conduction disturbance.Intracardiac EPS does not increase the risk of complications. Part two:The Clinical Study of Rhythm Disturbance after Transcatheter Closure of Ventricular Septal Defects.Background and objective:Transcatheter closure of ventricular septal defect has a high success rate with perioperative complications rate around3%.The heart rhythm abnormalities are common complications.The aim of this study was to retrospectively analysis the clinical risk factors and prevention measures of rhythm disturbance after transcatheter closure.Material and methods:From March2011to March2012,59patients had successful completion of transcatheter occlusion of VSDs in cardiovascular department of Zhongshan Hospital Affiliated to Fudan University.The clinical types of VSDs are as follows:simple perimembranous VSD(PMVSD) in44cases,simple muscular VSD (MVSD) in5patients, intracristal VSD (icVSD) in4cases, residual shunts after surgical repair of VSDs in4cases, post myocardial infarction ventricular septal perforation in2cases. The occluders implanted were produced in China.Surface ECGs were taken before and after the procedure immediately.and follow-up at the24th hour,48th hour,lst month,3nd month.and6th month after closure.Heart rhythm abnormality events were noted combined with data of clinical,ultrasonic cardiography.angiocardiography,to analysis the risk factors and prognosis of rhythm disturbance.Results:There were23cases(39.7%) of new-onset of arrhythmia including:3cases of I degree atrioventricular block(AVB).l case of left anterior hemiblock(LAH),l case of complete left bundle-branch block(CLBBB).7cases of complete right bundle-branch block(CRBBB),5cases of incomplete right bundle-branch block(IRBBB).l cases of I degree AVB combined with CRBBB.3cases of paroxysmal accelerated atrioventricular junction rhythm,1case of atrial premature beat,l cases of atrioventricular junction premature beat.Except1case sustained paroxysmal accelerated atrioventricular junction rhythm1year after closure,other22cases of arrhythmia recovered(total recover rate95.7%).Between rhythm disturbance group and non-rhythm disturbance group, there were significant differences in the respect of VSD type, distance from VSD rim to aortic valve and tricuspid valve, pulmonary pressure (P<0.05).While no significant differences were observed in aspect of age,body mass index(BMI),VSD size, membranous aneurysm, the type, size and manufacturer of occluder,residual shunts,procedure and fluoroscopy time(P>0.05). Pulmonary pressure was mainly related to the size and shunts of VSDs,so it was excluded from the risk factors.Further Logistic regression analysis of VSD type (PMVSD or nonPMVSD), distance from VSD rim to aortic valve and tricuspid valve revealed that these three factors had no correlation with postoperative rhythm disturbance (P value was0.212,0.066and0.6respectively). But for PMVSD group,Logistic regression analysis of VSD size,distance from VSD rim to aortic valve and tricuspid valve showed the most closely correlation between the latter and postoperative rhythm disturbance (P=0.021). Receiver operating characteristics curve (ROC curve) about the distance from VSD rim to tricuspid valve and incidence of no postoperative rhythm disturbance indicated that the area under the curve was0.732(with95%CI:0.587-878,P=0.008).According to the ROC curve,the cut-off point of the distance value prediction was12.5mm with the sensitivity of76.7%, specificity of61.1%, accuracy of70.8%, the positive predictive value of61.1%,the negative predictive value of76.7%and OR of5.16.Conclusion:The rhythm disturbance was common complication short term after transcatheter closure of VSDs,while mosty could recover to sinus rhythm.Preoperative accurate measurement of the distance from VSD rim to tricuspid valve using ultrasonic cardiography is very necessary.But what factors are exactly related to postoperative arrhythmia,and whether rhythm abomormalities affect the prognosis still need further study.