Comparison Of QRS Complex Duration And Synchrony Of Ventricular Among Different Right Ventricular Septum Pacing Sites

Objective To investigate the difference of different right ventricular septum(RVS)pacing sites on QRS complex duration(QRSd) and the index of synchrony of ventricular contraction and seek the best site of physiologic pacing.Methods Sixty-three patients(mean age67.00±10.8)with sick sinus syndrome scheduled for a permanent pacemaker implantation were divided into three groups according to the ventricular electrode pacing site,high septum(Group A20patients),mid septum(Group B25patients) and low septum(Group C18patients).Then the QRSd,early systolic mitral annular velocity(LV-Sm),interventricular mechanical delay(IVMD) and septal to posterior wall motion delay(SPWMD) were measured and compared before pacemaker implantation and24hours after programmed in DDD mode.Results After the pacemaker worked in DDD mode for24hours,the QRSd(ms)(Group A90.0±8.49vs135.65±6.58, Group B86.9±7.67vs112.08±9.58, Group C92.±11.31vs152.22±5.4IVMD (ms)(Group A7.80±2.04vs15.15±2.76, Group B6.20±3.04vs10.68±3.81, Group C7.22±3.77vs15.17±3.71) and SPWMD(ms)(Group A70.20±9.46vs106.10±9.86, Group B70.24±5.84vs89.96±8.55, Group C70.72±10.06vs114.72±10.87)of three RVS sites were significantly increased compared with ones before the implantation (P<0.05).Besides, the QRSd,IVVMD and SPWMD of mid septum was the shortest among three groups.Compared with group A(QRSd112.08±9.58vs135.65±6.58, SPWMD89.96±8.55vs106.10±9.86, IVMD10.68±3.81vs15.15±2.76) and group C(QRSd112.08±9.58vs152.22±5.44, SPWMD89.96±8.55vs114.72±10.87, IVMD10.68±3.81vs15.17±3.77;,there are both statistically significant(P<0.05).LV-Sm of three RVS sites presented the trend of decreasing,but there is no significant difference between them(P=0.069-0.442).There is significantly positive correlation between△QRSd and△SPWMD (rA=0.748, PA<0.001, rB=0.924, PB<0.001, rc=0.649, Pc=0.004),as well as△QRSd and△IVMD(rA=0.525, PA=0.017, rB=0.795, PB<0.001, rc=0.626, Pc=0.005).Conclusion RVS pacing of three different sites can lead to electric and mechanical asynchrony of ventricular contraction decrease.And the electric activity was related to mechanical synchrony.Mid septum may be the best choice for RVS pacing site.