Effect Of Right Ventricular Systolic Function By Left Univentricular Pacing In Realizing Cardiac Resynchronization Therapy

Objective To research the curative effect of realizing cardiac resynchronization therapy by using rate adaptive atrioventricular delay(RAAVD)function of triple chamber pacemaker and left univentricular pacing(LUVP),and then evaluate the influence of this pacing method on right ventricular systolic function.Methods 30 chronic heart failure patients with complete left bundle branch block(CLBBB)admitted to the Affiliated Hospital of Qingdao University from June 2015 to June2017 and met 2013 ACCF/AHA I a standard indication of implanting CRT were selected,of which 23 cases with dilated cardiomyopathy and 7 cases with ischemic cardiomyopathy all received optimal drug treatment and implanted CRT.The 1:1 matching was implemented before operation according to sex,etiology,NYHA classification and QRS duration,and then divided into LUVP group and BVP group with 15 cases in each.Under the echocardiography and electrocardiogram monitoring,the peak E was separated from peak A in LUVP group,where the interval atrioventricular with minimum malignant ventricular arrhythmia(MRA),maximum left ventricular ejection fractions(LVEF)and shortest QRS wave was regarded as optimal atrioventricular delay(AVD).Individualized AVD was set according to the regression equation of patients'heart rate and PR interval acquired by preoperative dynamic electrocardiogram,which was programmed into pacemaker.The rate adaptive function was opened to enable LUVP and track always follows physiological atrioventricular conducted activation of right ventricular to realize left univentricular fusion pacing.Similarly,in echocardiography and electrocardiogram monitoring,BVP group received optimization during AV and VV intervals.The differences between two groups were compared,including AVD,QRS duration,LVEF,left atrial diameter(LAD),left ventricular end-diastolic dimension(LVEDD),MRA,tricuspid annular plane systolic excursion(TAPSE),left ventricular filling time of the RR-interval(LVFT/RR),inter-ventricular mechanical delay(IVMD),septal to posterior wall mechanical delay(SPWMD),the time of pacemaker optimization and battery expected life.SPSS 22.0 statistical software was used to analyze the data,and P<0.05 was considered statistically significant sentence.Results Compared with pre-operation,after 12 mouth,the BVP group showed decreased post-operative AVD(150.1±5.4%vs.118.3±3.8%,P<0.05),QRS duration(173.8±11.5ms vs.145.4±8.16ms,P<0.05),LVEDD(75.1±9.2mm vs.58.3±6.0mm,P<0.05),MRA(4.7±0.8cm2 vs.3.9±0.6cm2,P<0.05),IVMD(76.9±7.2ms vs.56.7±6.4mm,P<0.05)and SPWMD(193.3±30.8ms vs.151±16.2ms,P<0.05);increased LVEF(31.4±2.2%vs.37.5±4.7%,P<0.05),TAPSE(16.8±2.4mm vs.21.6±2.6mm,P<0.05)and LVFT/RR(30.8±2.5 vs.41.8±3.8,P<0.05),the difference was statistically significant.LAD had no change(42.9±7.2mm vs.42.4±6.1mm,P>0.05).Compared with pre-operation,after 12mouth,the LUVP group showed decreased post-operative AVD(148.1±6.2ms vs.136.87±5.9ms,P<0.05),QRS duration(177.5±10.6ms vs.135.0±6.1ms,P<0.05),LAD(45.5±3.6 mm vs.42.9±2.9 mm,P<0.05),LVEDD(73.3±6.7 mm vs.55±5.5mm,P<0.05),MRA(5.1±0.8cm~2 vs.3.3±0.4cm~2,P<0.05),IVMD(79.7±6.2 mm vs.55.3±7.4 mm,P<0.05),SPWMD(209.2±27.2ms vs.150±16.5ms,P<0.05)and pacemaker battery life(7.5±0.4 years vs.5.4±0.4 years,P<0.05);increased LVEF(30.1±3.4%vs.41.4±8.4%,P<0.05),TAPSE(15.4±4.2mm vs.26.6±2.7mm,P<0.05)and LVFT/RR(32.2±2.6%vs.45.8±5.6%,P<0.05).Compared with BVP group,LUVP group showed increased post-operative AVD(136.87±5.9ms vs.110.3±3.8ms,P<0.05),TAPSE(26.6±2.7mm vs.21.6±2.6mm,P<0.05)and LVFT/RR(45.8±5.6%vs.41.8±3.8%,P<0.05),decreased QRS duration(135.0±6.1ms vs.145.4±8.16ms,P<0.05),MRA(3.3±0.4mm vs.3.9±0.6mm,P<0.05),and program control optimization time(26.3±2.5min vs.60.5±4.3min,P<0.05).Conclusions Both rate-adaptive atrioventricular delayed left univentricular pacing and traditional biventricular pacing can improve cardiac function and reverse ventricular remodeling in patients with chronic heart failure.The former is superior to the latter in extending left ventricular diastolic filling time,shortening QRS duration and improving right ventricular systolic function.Meanwhile,it can shorten the programmed optimization time and extend the battery life of pacemaker.