Pacemaker Implantation Changes In The Postoperative Cardiac Structure And Cardiac Function Study

The First Part Study the difference of ventricular function and structure between right ventricular apex pacing and outflow tract pacingAimsTo compare changes of ventricular function between patients without cardiac failure,paced in either right ventricular apex(RVA) or outflow tract(RVOT).To observe how cardiac chambers changed,and if right outflow pacing was better than right ventricular apex in patients with normal heart function.How would ventricular diastolic function change?MethodsEighty-two patients without prior heart failture were included in the study,including 46 male (56 percent),36 female(44 percent),from 32 years old to 87 years old,on an average of 69.26±11.55 years old.Atrial fibrillation was excluded.All these patients were randomized to RVA group or RVOT group.Then echocardiography was examed before pacemaker implantation,and after six months later echocardiography was repeated.The conventional biological and chemical examination were performed before the pacing operation.Through echocardiography,the sizes of the four cavities,ejection fraction,and pulmonary pre-ejection time(PPET),aortic pre-ejection time(APET) and their difference(AP), Ts-SD,LVEDV,LVESV,SV and CO were measured.The pacemaker parameters such as thresholds,impedances,R-range,QRS widen were measured at follow-up.Results1.The time to inseart the lead to satisfactional site of RVOT was longer than to RVA.2.Pacing threshold in RVOT was higher than RVA(P＜0.05) in operation time.No difference between two group after six months later.Impedances was lower in RVOT than in RVA,no matter how before or after pacemaker implantation.QRS widen was no difference between two group(P＞0.05).3.The heart structure were measured by echocardiography.There are no significant statistical different change in LA and RA.Anteroposterior diameter of LV in diastolic was decreased in RVOT than in RVA group(P＜0.05).Left and right diameter of right ventricle was increased in RVOT group than in RVA group(P＜0.05).The other sizes of heart were of no significant statistical difference.4.About cardiac function:there are no significant statistical difference compared with pre-operation in LVEDV,LVESV,CO,and no significant difference between two group RVA and RVOT.EF is decreased in RVOT group than pre-operation(P＜0.05).And SV was decreased in two group than pre-operation(P＜0.05).5.There were no significant difference between two group in A-P,PPET and APET.But compared with pre-operation,A-P,PPET and APET were increased in two group(P＜0.001).It means anywhere pacing can cause dissynchronization between two ventricles.6.There were no significant difference between two group in Ts-SD.Compared with pre-operation,IVST and IVST-MAX were increased in two group(P＜0.001).But there was no significant different between two group.It means anywhere pacing can cause dissynchronization in left ventricle.7.Preoperative Ts-SD＞32.6ms of the subgroup analysis of patients:In RVOT group,left and right diameter of left atrium was increased than in RVA group.Right ventricular diameter was increased in RVA than pre-operative.Left ventricular diastolic diameter was slightly decreased in RVOT group.There were no differences between the two groups.The other four sizes of the cavity were no significant changes(P＞0.05).Pacing in different parts of pre-operative and postoperative,EF,SV,CO did not change.There was no difference between the two groups in the inter-ventricular synchrony.Compared with pre-operation,PPEI and APEI were increased in two group.AP no change in the RVOT group.Ts-SD unchanged.8.Diastolic function:There was no significant difference in ventricular diastolic function between the two groups.But no matter which part of pacing,the group has a number of indicators about left ventricular asynchrony is significant changed.But this change has nothing to do with the site of pacing.ConclusionsRight ventricular pacing in different parts is a controversial issue.Our research shows that both apical pacing or outflow tract can be satisfied with the stability and function of the pacing. The pacing in different parts can cause each heart chamber a different but the most minor change, that show less clinical significance.Pacing can cause SV or EF reduced,but no significantly statistical difference in different parts of pacing.There were no significantly statistical differences in sync between right and left ventricles or inter ventricle.But significantly statistical differences in sync were showed in two groups than pre-operation Analysis the sub-group which Ts-SD＞32.6 before the pacemaker implantation,the conclusions were similar to those in front.There is no deterioration in synchronization and function of heart in two group.There was no significantly statistical difference in diastolic function and sync between two group.But varying degrees changed in diastolic sync after pacemaker implantation was showed significantly difference than before operation in all groups.For patients with normal heart function,anyplace pacing did not cause significantly changes in sizes of four heart cavities and heart function,but synchronization in systolic and diastolic were changed.Right ventricular outflow tract pacing has not shown better than apical pacing.As a result,the regions which the level of technology is limited,economic conditions is not rich,apical pacing is still a reliable pacing site.At present,into the outflow tract of pacing era is too early. The second part Using Real-time 3D echocardiography evaluated heart function and heart contraction synchronization in patients with right ventricular pacingResearch purposesIn patients without significantly change in the structure of heart and normal cardiac function, explore changes in ventricular systolic function and the characteristics of simultaneous contraction of the situation before and after pacemaker implantation.And further on the various pacing sites of pacemaker patients with real-time 3D echocardiography capacity-time curve analysis of real-time 3D echocardiography in the evaluation of patients with left ventricular systolic synchronicity of the mechanical aspects of the application.Information and methodsA total of 21 patients with normal cardiac function and pacemaker implantation were selected, of which 14 cases of male and female 7 cases.Cardiac echocardiography was measured preoperative and postoperative one month,three months.The instruments included conventional two-dimensional echocardiography,ultrasound diagnostic apparatus of Philips IE33 3D echocardiography,used in machines with the QLAB 6.0 3-D image analysis software.Acquisition of left ventricular 16 were calculated by sub-paragraph 16 of the left ventricle each time the volume and left ventricular automatically show overall and 16 of the volume - time curve(as shown in Figure 1),the calculation of the sections of the contraction Displacement of the mean, standard deviation,maximum and minimum.These values are measured three times in a row from the average of measurementsResultsIn the group of patients with left ventricular volume,and the risk of a left ventricular ejection fraction is normal.The overall size of the left ventricular displacement is the normal range,and between the various segments of the same uniform,each section of the displacement and the average standard deviation of the measurement results no significant difference(p＜0.05).Sections of the left ventricle to a minimum volume of time in between sections of the same uniform distribution(p＜0.05).One month and three-month real-time 3D echocardiography follow-up: compared with the former,with left ventricular volume,the risk of LVEF and no significant difference,displacement and sections of the left ventricle and the overall displacement There was no standard deviation also change(P＞0.05).To different parts of atrial pacing,pacing in the right atrial appendage patients,compared with the preoperative and postoperative left ventricular base of the wall after the middle of the wall and displacement increased,and the interval before the middle of the displacement are reduced.And to achieve significant difference(in the former vs after:the basement of the left ventricular wall after 4.1±0.5ram vs 5.6±0.8mm,P= 0.03.the middle of the wall under 4.3±0.4mm vs 5.2±0.6mm,P= 0.04,Before the middle of the interval 5.1±0.4mm vs 4.6±0.Smm,P = 0.02).In the interval pacing patients,compared with the preoperative and postoperative left ventricular basement of the interval before the displacement increased,the middle of the wall under the displacement and to reduce the significant difference (in the former vs after:Left Room basement before the interval of 3.9±0.6mm vs 5.3±0.6mm,P = 0.02,the middle of the wall under 4.4±0.6mm vs 3.6±0.7mm,P = 0.03).The remaining segment of the systolic displacement was no significant difference(P＞0.05).ConclusionIn patients with normal heart function,the apex and outflow pacing,the volume of the left ventricle,the LVEF,as well as the overall and left ventricular segmental contraction has not changed,but different parts of the atrium and the right atrial appendage from the interval risk arising from different segments of the left ventricle contraction change.Therefore,the outflow pacing heart function in the normal population is not necessary to choose the pacing site.The different parts of atrial pacing will bring what about the clinical significance which need us to explore further.