| Objective: To compare ECG characteristic of different right ventricular pacing sites and the acute impact of ventricular pacing on cardiac function by ECG and speckle-tracking echocardiography(STE).Methods: Patients were divided into retrospective group and prospective group.Retrospective group: patients were implanted with dual chamber pacemakers,including sick sinus syndrome(SSS)、atrioventricular block(AVB)and SSS+AVB(n=131).According to the pacing site in medical record,retrospective group was divided into mid septum、mid-low septum、low septum and apex group.Prospective group: patients who were implanted with dual chamber pacemakers,including SSS 、 AVB and SSS+AVB(n=85).According to the proportion of ventricular pacing after surgery,they were divided into VP(the proportion of ventricular pacing≥90%)、 VP-VS(the proportion of ventricular pacing≥80% and <90%)、VS(the proportion of ventricular pacing<80%)group.QRS duration、Tp-Te interval and R height were measured by twelve led electrocardiogram in retrospective group before and after surgery.Observe the function of left ventricular before surgery 、after pacemaker implantation surgery 1 week and 2 minutes after surgery 1 week when chang the pacing mode by programming(Record the pacing mode after pacemaker implantation surgery 1 week.When the pacing mode is VP,change VP into VS by Prolonging A-V delay interval appropriately if possible;When the pacing mode is VS,change VS into VP by shortening A-V delay interval appropriately).Survey the index of left ventricular by STE: left ventricular end-systolic dimension(LVDs)、 left ventricular end-diastolic dimension(LVEDd)、Left ventricular ejection fraction(LVEF)、A peak、E/A、A peak velocity time integral(A-VTI)、Strain(S)、Strain rate(SR).Data were processed with SPSS 20.0 software.When the measurement data are subject to normal distribution and homoscedasticity,continuous variables were expressed as the mean ± standard deviation,Prospective group were compared using repeated measures.Means were compared using t test.P value of <0.05 was considered statistically significant.Results: 1.parameter in retrospective group: QRS duration is wider after surgery than in preoperative(104±27ms to 125±40 ms;103±22 ms to 139±26 ms;97±34 ms to 164±24 ms;64±35 ms to 171±57 ms,P<0.05).QRS duration in mid septum group is the shortest than in mid-low septum group、low septum group and apex group.Difference between groups is statistically significant(P<0.05).There is no significant difference in preoperative、after surgey and no significant difference between mid septum group、mid-low septum group、low septum group、apex group to Tp-Te interval and R height(P>0.05);2.parameter in prospective group:QRS duration is wider after surgery than in preoperative(94±11ms to 146±62ms;102±31ms to 133±38ms;82±27ms to 125±34ms,P<0.05).There is no significant difference in VP group、VP-VS group and VS group to QRS duration(P>0.05).About Tp-Te interval and R height,there is no significant difference in preoperative and after surgey and no significant difference between VP group、VP-VS group and VS group(P>0.05).BNP is significant decreased compared with in preoperative and after surgery(181±36pg/ml to 95±20pg/ml;201±69pg/ml to 102±47pg/ml;177±10pg/ml to 58±34pg/ml,P<0.05)and has no difference between VP group、VP-VS group and VS group(P>0.05).There is significant difference in groups to left ventricular strain(P<0.05).In VP group(-19.0±0.9%、-13.6±4.5%、-15.4±4.4%)and VP-VS group(-21.0±5.2 %、13.3±5.6 %、-15.2±5.5 %),compared with the parameter before operation,left ventricular strain decreases after surgery 1 week,while increases in 2 minutes after surgery 1 week by programming the mode from VP to VS(P <0.05).In VS group(-16.3±3.2%、-15.2±5.5%、-12.8±3.1%),compared with parameter before operation,left ventricular strain decreases after surgery 1 week,and continues decreasing in 2 minutes after surgery 1 week by programming the mode from VS to VP(P <0.05).There is no significant difference between VP group、VP-VS group and VS group to left ventricular strain(P>0.05).There is no significant difference in preoperative 、 1 week after pacemaker implantation surgery 、 2 minutes after surgery 1 week by programming(P>0.05)and no significant difference between VP group、VP-VS group and VS group(P>0.05)to Tp-Te interval、R height、LVDs、LVEDd、LVEF%、A-VTI、A、A/E、SRs、SRe and SRa.Conclusions:1 In mid septum group,the QRS duration is the narrowest than in mid-low septum group、low septum group and apex group for patients with pacemaker implanted 1 week later.2 There is no statistics difference to parameter of cardiac structure in groups and between groups(VP group、VP-VS group and VS group)for patients with different pacing proportion 1 week after pacemaker implanted.3 There is statistics difference to left ventricular Strain when change the pacing mode immediately.Left ventricular Strain increases immediately by programming the mode from VP to VS.Left ventricular Strain decreases immediately by programming the mode from VS to VP. |
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