Clinical Study Of Right Ventricular OutflowTract Pacing

Objectiv:To compare the pacing parameters, contraction synchrony and cardiac performance between RVA and RVOT pacing and provide evidence for more reasonable pacing modeMethod:sixty patients (average age 66.40±16.09 years,male cases 29,female cases 31 ) with bradyarrhythmia were randomized into RVA group (n=30 ,average age 68.83±15.88 years,male cases 13,female cases 17 ) and RVOT group (n=30 ,average age 63.97±16.21 years,male cases 16,female cases 14 ), the pacing parameters and operative complications were collected to evaluate the feasibility of RVOT pacing, the ventricular synchrony was evaluated by QRS duration,APEI -PPEI and Ts-SD-12( standard deviation of time to regional peak systolic velocity),while the cardiac performance was appraised by the diameters of left atrium, left ventricle and LVEF.Results:All the patients underwent implantation smoothly and no significant differences were noted in complications,mean follow-up time was 11.47±1.67 months ,there was no statistics difference as compared with threshold and sensitivity of pre-implantation and post-implantation inter- and intra-groups, compared with pre-implantation,the impedance of two groups was significantly lower at 3 and 12months post- implantation(P<0.01),which was more lower in RVOT group than that of RVA group(P<0.01),the enlargement of QRS duration could be observed immediately after ventricular pacing, but the degree of RVOT group was significantly alleviated,APEI—PPEI and Ts-SD were significantly changed immediately after ventricular pacing(P<0.01),and the value of RVA group were great than those of RVOT group ,the left atrial dimension( LAD) and left ventricular end-systolic diameters( LVESD) of two groups were not statistically changed ,the left ventricular end-diastolic diameter (LVEDD )of RVA group increased significantly 12 months later compared with pre-implantation(P<0.05),the left ventricular ejection fraction (LVEF) decreased significantly between two groups at 12 months post-implantation, (RVOT group, P<0.05;RVA group, P<0.01). Correlation analysis:The cumulative percentage of right ventricular pacing (Cum%VP) had a positive relationship with△LVEDD(r=0.78, P<0.01)in RVA group, and there was a significant negative correlation between LVEF and QRS duration post-implantation (r=-0.58, P<0.01).Conclusions:RVOT pacing proved to be feasible and stable ,which results in a better ventricular contraction synchrony and cardiac performance,correlation may exist between Cum%VP and cardiac dysfunction...