The Effects Of Different Pacing Sites Of Right Ventricle On ECG And Left Ventricular Function

Background and AimsSince the last century 50 years, Pacemakers have been used in clinical. Cardiac pacing has not only brought new life to patients, and improved the quality of life in patients. In the past, right ventricular apical (RVA) pacing has been widely used. In this position, pacing electrodes easily be fixed.But recent studies have shown that RVA pacing may cause abnormal electrical emotion model, lead to non-synchronous myocardial contraction, have adverse effects on hemodynamics, long-term RVA pacing ventricular function can be directly damaged, affecting myocardial perfusion and lead to myocardial remodeling. While the right ventricular septal (RVS) near the His bundle, you can directly implement the "near His-bundle pacing". Double ventricular electrical synchronous conducive to the left and right ventricular mechanical synchronization contraction, can improve LVEF, to obtain better acute hemodynamic effects. Therefore, the hemodynamic parameters of RVS pacing were superior to RVA pacing.This study compared right ventricular pacing in different parts of QRS duration of the ECG,left ventricular eiection(LVEF)and left ventricular end-diastolic diameter(LVEDD),to evaluate the effects of pacing in RVS and RVA on ECG and heart function. Methods19 cases have selected from the Sir Run Run Shaw Hospital and Jiangshan City People's Hospital, from October 2007 to October 2009. All the cases are in line with permanent cardiac pacemaker Class I indications. All patients were New York Heart functional classⅠ-Ⅱlevel, and there is no intraventricular conduction block. Accordance with the ventricular electrode site,39 with implanted DDD pacemaker patients were randomly divided into two groups. A group of septal pacing (RVS group, 20 cases,12 males and 8 females), (70.2±11.7) years of age; the other group apical pacing (RVA group,19 patients,11 males and 8 females), (69.7±9.5) years of age.In age, gender, pre-operative QRS wave width and cardiac function, the two groups was no significant difference. QRS wave width,LVEF and LVEDD of two preoperation groups and after operation groups with 3-month following-up were compared.Results1. The width of QRS wave in ECGⅡlead RVA group preoperative (0.11±0.05) S vs postoperative (0.20±0.03) S(P< 0.01), postoperative the width of QRS wave was significantly enlarged;RVS group preoperative(0. 11±0.02) vs postoperative (0.12±0. 04)S(P> 0.05), postoperative the width of QRS similar to preoperative; Contrast postoperative the width of QRS of RVS group and of RVA group, the former significantly narrower than the latter(P <0.01).2. Indicators of cardiac function①LVEF:RVA group preoperative(62.36±3.47)% vs postoperative three-months (49.65±4.31)%(P< 0.05), postoperative three-months LVEF Significantly decreased; RVS group preoperative (61.24±2.87)% vs postoperative three-months 60.31±3.89)%(P> 0.05), postoperative three-months LVEF is no obvious change; Contrast postoperative three-months LVEF of RVS group and of RVA group,RVA group also decreased significantly(P< 0.05).②LVEDD:RVA group preoperative (45.13±5.67) mm vs postoperative three-months (51.45±4.57) mm(P< 0.05), postoperative three-months LVEDD significantly increased; RVS group preoperative(44.36±4.36)mm vs postoperative three-months (46.02±3.89) mm (P> 0.05), postoperative three-months LVEDD is no obvious change; Contrast postoperative three-months LVEDD of RVS group and of RVA group,RVA group also increased significantly(P< 0.05).ConclusionsThis study showed that:QRS wave after RVA pacing was obviously enlarged compared with the preoperative, Showed left bundle branch block graphics, Compared with RVS pacing also significantly widened. after RVA pacing LVEF was significantly decreased, LVEDD was significantly increased, Compared with RVS pacing also were significantly different.RVA pacing electrical pulses to the interventricular septum from the apex of retrograde conduction, Most left ventricle through the cardiac conduction, Depolarization speed is slow, Left ventricular itself and biventricular depolarization is not synchronized. Interventricular septum, apex and left ventricular posterior wall motion was abnormal, Cardiac contraction is not synchronized, the loss of the overall coordination, and to reduce ventricular compliance, And thus on hemodynamics and cardiac function produces a wide range of adverse effects. The RVS pacing QRS-wave width, LVEF, LVEDD, and surgery had no significant difference than preoperative. As the right ventricular septal close to the His bundle, you can directly implement the "near His-bundle pacing," pairs of ventricular depolarization time, as far as possible to maintain the normal ventricular activation sequence pairs and pairs of ventricular synchronous mechanical contraction, and get more good hemodynamic results.Therefore, for those patients need implanted pacemakers and inadvertent intraventricular conduction block, from the perspective of long-term cardiac function, RVS pacing is better than RVA pacing pacing.