Echocardiography In Evaluating Ventricular Function And Ventricular Segments Motion Of The Patients With Sick Sinus S Syndrome And Atrioventricular Delay On AAI Pacing Mode And DDD Pacing Mode

DDD pacing mode, AAI pacing mode and VVI pacing mode were used for the treatment of sick sinus syndrome (SSS). Many reports showed that physiological pacing modes(DDD and AAI) were superior to VVI for the following reasons: cardiac output, complications of atrial fibrillation, thromboembolism, heart failure, the survival rate and quality-of-life. In patients with preserved AV conduction who were receiving a pacemaker mainly for SSS, AAI pacing mode had been shown to be electromechanically superior to DDD pacing mode due to the natural ventricular activation pattern. However, there was evidence suggesting that the presence of natural AV synchrony in AAI pacing mode was not enough for hemodynamic benefit to occur. The intrinsic conduction time was also an important variable.There were disadvantage factors in both pacing modes(AAI or DDD) on the patients with SSS and prolonged atrioventricular delay. The choice was a problem in these patients. The aim of the study was comparing the contribution of both pacing modes on these patients and giving an advice to lead the clinic treatment.【Objective】The aim of this study was to evaluate cardiac function and ventricular segments motion by echocardiography in patients with Sick Sinus Syndrome(SSS) and first degree atrioventricular block(AVB), who underwent AAI mode pacing or DDD mode pacing.【Methods】This study included 24 patients(13 men and 11 women, mean age 69.75±7.38(SD) years old) with DDD pacemaker for SSS and first degree AVB(PR interval＞200ms and＜260ms). The pacing mode of these patients was programmed on AAI pacing mode or DDD pacing mode with optimal atrioventricular interval. The parameters of systolic and diastolic function of left ventricular and right ventricular was measured using doppler echocardiography and tissue doppler imaging(TDI) and the parameters of ventricular segments motion were measured using quantitative tissue velocity imaging at four-chamber view, two-chamber view and apical longitudinal view. The regional parameters, including peak sustained velocity(Vs), peak early diastolic velocity(Ve), peak late diastolic velocity(Va) and peak systolic displacement(D), of the basal and middle segments in left ventricle (anterior septal, anterior, lateral, posterior, inferior and septal wall) and in the free wall of right ventricle were measured.【Results】(1) The analysis of left ventricular showed there were no significant differences in the parameters of LVEF, VTI, E, A and E/A between AAI mode group and DDD mode group [P＞0.05]. The parameters of Sm, Em and Em/Am in AAI mode group were greater than that in DDD mode group [Sm: 10.88±2.92 cm/s vs 9.06±2.49cm/s, P＜0.05; Em: 9.25±2.89cm/s vs 8.37±2.31cm/s, P＜0.05; Em/Am: 0.96±0.35 vs 0.80±0.25, P＜0.05]. The Tei index in AAI mode group was lower than that in DDD mode group [Tei index: 0.56±0.12 vs 0.80±0.40; b: 456.68±50.86ms vs 261.90±48.23ms, P＜0.05].(2) The analysis of right ventricular showed the parameters of RVPEP,RVPEP/RVET in AAI pacing mode group were lower than that in DDD pacing mode group[RVPEP: 98.28±23.02 ms vs 14.33±22.72ms, P=0.002; RVPEP/RVET: 0.33±0.09 vs 0.39±0.09, P=0.010). The Sm' measured using TDI in AAI pacing mode group was greater than that in DDD pacing mode group [14.67±3.07cm/s vs 12.78±2.72cm/s, P=0.013]. The other parameters of diastolic function and Tei index were showed no significant differences between the AAI pacing mode group and DDD pacing mode group.(3) The parameters of ventricular segments motion were analysed by QTVI. The result showed there were significant differences in the parameters(Vs, Ve) of most basal segments between AAI group and DDD group[P＜0.05]. Other parameters were no significant differences between both modes[P＞0.05].【Conclusion】(1) The systolic and diastolic function of left ventricular of the patients with SSS improved under the AAI mode pacing therapy better than under the DDD mode pacing therapy; The systolic function of right ventricular under AAI pacing mode was better than it under DDD pacing mode.(2) The change of cardiac systolic and diastolic function could be evaluated by TDI sensitively more than by doppler echocardiography;(3) Tei index is useful to determine the optimal pacing mode in patients with SSS and first degree AVB;(4) The change of ventricle segments motion can be early evaluated by QTVI in AAI and DDD mode, and it is useful to determine the optimal pacing mode in SSS patients withⅠdegree AVB.