A Hemodynamic Study In Patients With Righ Ventricular Septal Pacing

PerfaceSince the introduction of permanent pacing,the preferred site for ventricular stimulation has been almost exclusively the right ventricular apex(RVA);because RVA pacing provides lead stability and low capture thresholds.However,RVA pacing altered ventricular depolarization vector and increased ventricular asynchronous contraction, which resulted in deterioration of left ventricular function.Pacing from the right ventricular septal(RVS)may provide better performance of the heart because it has a almost normal ventricular activation and conduction sequence.However,previous studies have not obtained consistent results about RVS pacing,the possible reasons for this might be difference in patient selection,exactly pacing position in RVS and evaluation criteria and the time of evaluation after the implantation.More studies need for further understanding of benefits of RVS pacing.ObjectiveThis study is aimed to compare the contraction synchrony and cardiac performance between RVA and RVS pacing.Methods:Thirty-two patients(mean age 65.3±12.9 years)without structural heart disease were studied.The patients were randomized into RVA group(n=16) and RVS group(n=16).The operation time and ventricular threshold changes trend were collected to evaluate the feasibility of RVS pacing.The ventricular synchrony was evaluate by QRS duration,PPEI-APEI and Ts-SD,while the cardiac performance was appraised by Tei index.ResultsThere were no differences in operation time and threshold parameters between RVS and RVA pacing.Compared with pre-implantation the QRS duration,PPEI-APEI and Ts-SD increased significantly changed immediately after ventricular pacing(p＜0.01).The mean QRS duration was 155.3±12.7ms for RVA pacing and 143.6±6.5ms for RVS pacing(p＜0.001)..Ts-SD was 48.70±3.81 ms for RVA pacing and 41.93±3.58 ms for RVS pacing(19＜0.001).At 6 months after pacing,the Tei index was 0.509±0.07 for RVA pacing and 0.415±0.06 for RVS pacing(p＜0.05).the PPEI-APEI was-34.82±8.07ms for RVA pacing and -28.65±7.81ms for RVS pacing. Analysis suggested that compared with RVA pacing,QRS duration was shorter, ventricular contraction was more synchronimous during RVS pacing,resulting in better cardiac performance.Both the enlargement of QRS duration and absolute value of PPEI-APEI had a positive relationship with the change of Tei index.ConclusionsRVS pacing is feasible and it results in better ventricular contraction synchrony and cardiac performance.