Clinical Investigation Of Optimal AV Delay In Differents Right Ventricular Pacing Sites Ways In Patients With Implanted DDD Pacemakers

Objective To compare the differences of heart function and the hemodynamic effects of right ventricular septum (RVS) pacing and right ventricular apex(RVA)pacing before and after optimizing in patients undergoing DDD pacemaker implantation.Methods 37 cases with third degree atrioventricular block (Ⅲ°AVB) underwent DDD pacemaker implantation, including 19 cases with RVA pacing and 18 cases with RVS pacing. Optimal AV delay was achieved in all patients. The atrioventricular delay(AVD), left ventricular Tei index ( LV-Tei ) , right ventricular Tei index ( RV-Tei ) , left ventricular ejection fraction (LVEF) , stroke volume (SV) , QRS duration of ECG of before and after optimizing were compared.Results In RVA pacing group, LV-Tei, QRS duration of ECG decreased significantly after optimization(0.42±0.12 vs 0.37±0.10; 60. 70ms±12.69ms vs 142.10ms±11.88ms, all P＜0. 01) ; and SV,LVEF increased significantly (69.55ml±17.47ml vs 82.61ml±22.81ml, P＜0.01;0.53±0.06 vs 0.55±0.06, P＜0.05) . In RVS pacing group, there was no significant change in QRS duration of ECG, AVD,RV-Tei decreased significantly after optimization (192.69ms±42.65ms vs 163.08ms±37.89ms;0.42±0.09 vs 0.38±0.09, all P＜0. 05); SV,LVEF increased significantly (76.93ml±17.57ml vs 85.74ml±20.28ml , P＜0.01;0.55±0.03 vs 0.57± 0.03,P＜0.05) .Conclusions improvement of hemodynamics and heart function were achieved in all patients after optimal atrioventricular delay. Improvement of left ventricular function in RVA pacing , while improvement of rigt ventricular function in RVS pacing, respectively.