Interval And The Apex Of Pacemaker Ultrasonic Observation In A High Impact On Cardiac Function And Left Ventricular Systolic Synchronicity

ObjectiveTo investigate the effects of high right ventricular septal or right ventricular apical pacing on the synchronization of the left ventricular contraction and cardiac function by color ultrasonic Doppler.Method42Patients who was implanted pacemaker for sick sinus syndrome or atrioventricular block were divided into two groups according to the pacing site, high right ventricular septal (HRVS) pacing group (22patients) and right ventricular apical (RVA) pacing group (20patients). However the data of four patients was deleted because the ultrasound was disturbed. In the remain of the patients, HRVS pacing group (19patients) and RVA pacing group (19patients) were entered into the study at average21months (18to24months) observation. Left ventricular end diastolic diameter (LVEDD).left ventricular ejection fraction (LVEF), time-to-peak velocity (Ts). septal posterior wall motion delay (SPWMD) and (E/E’) were measured. All the data was analyzed statistically between the two groups.ResultsCompared with the preoperation, no significant change of LVEDD was found in HRVS pacing group, however, LVEF was significantly increased (P<0.05) in HRVS pacing group after operation. Compared with the preoperation, LVEDD was significantly increased (P<0.01) and LVEF was markedly decreased (P<0.01) in RVA pacing group after operation. The LVEF of HRVS pacing was significantly higher than RVA pacing group (P<0.01) after operation. However the LVEDD of HRVS pacing was smaller than RVA pacing group (P<0.05) after operation. E/E’ was found to be not different between the two groups after operation. Compared with HRVS group, time to-peak velocity in some myocardial segments were delayed in RVA group (P<0.05) after operation, especially in the left ventricle lateral wall and posterior wall (P<0.01). Compared with HRVS group. Ts-SD and SPWMD were higher in RVA group (P<0.05) after operation.ConclusionHigh right ventricular septal pacing is better than right ventricular apical pacing in improving the synchronization of the left ventricular contraction and cardiac function in patients with pacemaker implantation.