Impact Of Different Right Ventricular Site Pacing On Cardiac Hemodynamics And Myocardial Motion

Objective:To investigate the impact of High septum, Low septum and Right ventricular apex pacing on cardiac hemodynamics,electrocardio-activation and systolic synchronicity for patients with auriculo-ventricular block.Methods:Seventy-five patients having been implanted VVI pacemaker because of arriculo-ventricular block were selected at first.The last 60 patients were eligible participate in this study for the last follow-up visit result of pacing percent >40%,and were randomly divided into group A, B and C, according to different electrode pole site. The group A is Rihgt ventricular apex pacing group and have 20 patients (12 male and 8 female); The group B is High septum pacing group and have 20 patients (11 male and 9 female); and the Group C is Low septum pacing group and have 20 patiengs(10 male and 10 female )too. The general data of preoperation and postoperative follow-up 12 mounths was recorded. Pacing ECG in quiescent condition,hemodynamic parameters (LVEF,LVFS,LVSV)measured by echocardiography from the long axis view of left ventricle,the doppler imaging from the apical four chamber view and the apical two chamber view and left ventricular long axis view in the TVI mode during pacing as well as were recorded. The time-speed curve of the movement of right ventricular lateral wall,interventricular septum and left ventricular lateral wall from the apical four chamber view was harvested, the time-speed curve of the movement of left ventricular anterior wall, inferior wall,left ventricular anterior septal,posterior wall the apical two chamber view and left ventricular long axis view was collected too, the interval of contractile and diastolic time at basal and middle parts of left and right ventricular were measured for to evaluate the variation of myocardial motion at different right ventricular point pacing.Result:1. General data was compared before operation:All of the groups'general data (sex,age,based cardio disease, hemodynamics, electrode materials,threshold frequency, percent pacing rate)has no different(P>0.05). 2. Hemodynamics(LVEF,LVFS,LVSV) were compared after operation follow up 12 mounths: There were no significant different of hemodynamics before implantation pacemaker among all groups(P>0.05);there have lower than before implantation pacing maker within all groups(P<0.05);the high septum pacing group was highest in all groups, the low septum pacing group followed,the Right ventricular apex pacing group was lowest (P<0.05).3. Pacing simultaneous ECG QRS complex width was compared after operation follow up 12 mounths:There were significant different among all groups, Pacing simultaneous ECG QRS complex width of the high septum pacing group was shortest in all the groups, the low septum pacing group follow up, the right ventricular pacing group was longest (P<0.05).4. Myocardial motion data in pacing condition was compared after operation follow up 12 mounths: There were significant different of systole during R wave peak time and diastole during peak time deferent left ventricular segments in one cardiac cycle among all groups in different right ventricular point pacing(P<0.05).R wave systole peak time:left ventricular lateral wall basal segment and middle segment ;interventricular septum middle segment; right ventricular free wall basal segment, left ventricular inferior wall basal segment and middle segment; left ventricular anterior septum middle segment; left ventricular posterior basal segment and middle segment;septum basal segment has delayed in during systole time. R wave diastole peak time:left ventricular lateral wall basal segment and middle segment;right ventricular free wall basal segment and middle segment;left ventricular inferior wall basal segment and middle segment;left ventricular anterior septum wall middle segment;left ventricular posterior wall basal segment and middle segment;left ventricular basal segment has delayed in during diastole time.Ventricular mechanical systole synchronism:There have significant different of the dispersion of left ventricular systole Ts-SD(standard deviation of systole peak time of deferent left ventricular segments in one cardiac cycle)and the range of systole peak time in left ventricular Ts-maxD(the equation of maximal value and minimum value of systole peak time of deferernt in one cardiac cycle) among the high septum pacing group,the low septum pacing group and right ventricular pacing group and between the right ventricular with the left ventricular (P<0.05).5. After operation follow up 12 mounths, Corelation analysed pairwise comparison group between Pacing simultaneous ECG QRS complex width, Hemodynamics (LVEF,LVFS,LVSV), Myocardial motion data in pacing condition:Pacing simultaneous ECG QRS complex width negatively corelate with hemodynamic, pearson LVEF,LVFS -0.696,LVSV -0.174;and positively correlate myocardial motion, pearson inter left ventricular Ts-SD 0.611,Ts-maxD 0.679, between left and right ventricular Ts-SD 0.602,Ts-maxD 0.733. there have significan correlation between electric conduction and myocardial motion. Left ventricular mechanical motion correlate negatifely with hemodynamics.in different right ventricular point pacing.Conclusion:1. It is proved that the high septum pacing group has the best of electro-synchronism and mechanical systole synchronism and hemodynamics,and that the low septum follow,and that the right ventricular pacing group has the worst by tissue dopplar.2. It is proved that ventricular electro-asynchronism is relating with hemodynamics deteriorated,cardic electro-asynchronism is relating with ventricular mechanical systole asynchronism, and ventricular mechanical systole asynchronism is relating with hemodynamics deteriorated by tissue dopplar.