Dual-chamber Pacing In Different Av Interval On The Synchronization Of The Heart And Blood Flow Dynamics Affect

Objective:To observe changes of the AV interval and its effect on the electric synchronism as well as hemodynamics inⅢ°AVB patients with dual-chamber pacemakers.Method:From March 2005 to January 2009,36 patients implantend pacemaker forⅢ°atrioventricular block were divided into two groups according to the pacing site, HRVS pacing group(21 patients) and RVA pacing group(15 patients). Use two-dimensional echocardiogram to record mitral Doppler flow spectrum, optimize AV interval by observing the relative relationship of diastolic early and late peak (E peak and A peak)filling velocity. Take the best relationship of E peak and A peak as OAVD or as the optimal AV delay(OAVD). LVESV, LVEDV, LRVPEI, SPWMD, LVEF and MR were measured at OAVD, OAVD-20ms, OAVD+20ms in 3th months,6th months and 12th months after the implantation. At last, all the data undergoing statistical analysis.Results:There was no significant difference in clinical characteristics between HRVS pacing group and RVA pacing group before pacemaker implantation(P>0.05). After pacemaker implantation 3 months, OAVD of HRVS pacing group was160.95±21.89ms, compared with the 159.33±16.24ms of RVA pacing group had no significant difference(P>0.05). At OAVD, the SPWMD and LRVPEI of HRVS pacing group was smaller than that of RVA pacing group(P<0.05), other dates were similar between the two groups(P>0.05). In HRVS pacing group, the LRVPEI of OAVD was smaller than that of OAVD-20ms, and OAVD+20ms (P<0.05), other dates had no significant difference(P>0.05). In RVA pacing group, There was no significant difference beween OAVD and OAVD-20ms, OAVD+20ms(P>0.05). After pacemaker implantation 6 months, OAVD of HRVS pacing group was157.62±17.86ms, compared with the 157.33±26.04ms of RVA pacing group had no significant difference(P>0.05). At OAVD, the LRVPEI and SPWMD of HRVS pacing group was smaller than that of RVA pacing group(P<0.05), other dates were similar between the two groups(P>0.05). In HRVS pacing group, the LRVPEI,SPWMD and LVESV of OAVD had significant difference compared with those of OAVD-20ms, and OAVD+20ms (P<0.05), LVEF,LVEDV had no significant difference(P>0.05). In RVA pacing group, the LRVPEI,SPWMDå'ŒLVESV of OAVD had significant difference with those of OAVD-20ms, and OAVD +20ms (P<0.05), LVEDVå'ŒLVEF had no significant difference(P>0.05). MR of OAVD was smaller than that of OAVD+20ms (P<0.05). After pacemaker implantation 12 months, OAVD of HRVS pacing group was 152.38±17.29ms ms, compared with the150.67±21.87ms of RVA pacing group had no significant difference(P>0.05). At OAVD, the LRVPEI,SPWMD and LVESV of HRVS pacing group was smaller than that of RVA pacing group(P<0.05), the LVEF of HRVS pacing group was more than that of RVA pacing group(P<0.05), the LVEDV was less than that of RVA pacing group, but there were no significant difference beween two groups(P>0.05). In HRVS and RVA pacing group, the LRVPEI,SPWMD and LVESV of OAVD had difference compared with those of OAVD-20ms, and OAVD+20ms (P<0.05), LVEDV,LVEF had no significant difference(P>0.05). The change of OAVD of the same individual at different times had significant difference(P>0.05). Theâ–³LVEF had a good correlation withâ–³LRVPEI andâ–³SPWMD of two groups after 3 months,6 months and 12 months.Conclusions:OAVD of the different pacing sites has no significant difference. OAVD of the same persons changes over time. The different pacing sites and the different AV delay both inpact electric synchrony and hemodynamics.