A Comparative Study Of Short-term Clinical Effect Difference Of The Optimal Position Of Right Ventricular Septal Pacing And Right Ventricular Apex Pacing

Objective: This study was designed to explore the optimal position of right ventricularseptum（RVS）pacing by assessing QRS duration and a comparison of short-termclinical effect difference of RVS pacing and right ventricular apex pacing.Methods:1.Pacing and electrocardiography recording were underwent at， rightventricular septum（RVS），were divided into3pans(high，middle and low)(Thedefinition of right ventricular septal based on Ding Li［1］)respectively in40patientsheat who accept electrophysiological examination. Then the duration and morphologyof QRS complex paced in different right ventricular locations were analysed andcompared. The best stimulation place of Stimulation was the position which results thenarrowest QRS durations.2. We selected45patients with permanent cardiac pacemaker implantation，whoimplanted type DDD or DDDR pacemaker for the first time，pacemaker，andseparated them into three groups according to different ventricular lead placement anddifferent pacing ratio of right ventricular：the matched group，right ventricularapex(RVA) pacing group and right ventricular septum(RVS) pacing group. Threegroups were analysed preoperation、one week after operation and three months afteroperation in terms of echocardiogram feature、the level of plasma BNP and12-leadelectrocardiogram. Three groups were analysed one week after operation and threemonths after operation in recording threshold，perception，impedance parameterswhen programming pacemaker.The following parameters were obtained:Leftventricular end diastolic dimension(LVEDD)、 left ventricular ejection fraction（LVEF）and the velocity time integral aorta （AVTI）were to asses left ventricularcontractive function. After operation，tissue synchronization imaging (TSI) obtainedsimultaneously the apical4-chamber,3-chamber and2-chamber of long-axis views ofthe left ventricular apex.The data were post-processed offline, and a TSI surface mapof left ventricular colorized according to the time-to-positive peak systolic velocity(TTP)was generated to reflect the segment TTP semi-quantitatively. The segmentalTTP of the six-basal and six-mid segments of left ventricular was measured andcompared to assess intraventricular synchrony. Results:1.the width of post—pacing QRS was narrowest at middle septal (136.7±16.1ms)，had significant difference compared with he low septal（149.8±18.0ms）and high septal（154.9±16.7ms）(P<0.001).2. Threshold、perception and impedance parameters were measured during implantation and at each follow-up visit，there was no significant differences in pacing parameters.3. After operation，the QRS duration was significantly prolonged in the RVApacing group then RVS pacing group [(146.5±11.1ms) vs (162.2±11.6ms)P<0.001]。4. Preoperation、one week after operation in the matched group、the RVA pacing group and the RVS pacing group，the level of plasma BNP had no significant deference(P>0.05)， three months after operation，compared to thematched group（85.3±44.9pg/ml）and the RVS pacing group（145.0±116.1pg/ml） the level of plasma BNP in the RVA pacing group（225.5±148.9pg/ml）rose significantly (P<0.05).5. There were no significant differences in the parameters of LVEDD、LVEFand AVTI in the matched group，right ventricular apex(RVA) pacing group and right ventricular septum(RVS) pacing group.(P＞0.05).6. After operation， the time-to-positive peak systolic velocity (TTP) of Leftventricular had better intraventricular synchrony in the RVS group，had significantdifference compared with the RVA pacing group (P<0.05).Conclusions：The width of post—pacing QRS wave in the middle septum group isnarrowest.After short time of follow-up，the RVS pacing group is safety andfeasibility，which is superior to the RVA pacing group in terms of intraventricularsynchrony and has smaller effects on heart function than the RVA pacing group.