Analysis And Comparison Of The Different Pacing Modes In Patients With Sick Sinus Syndrome

Objective:Analyze and compare the acute hemodynamic,the frequency of atrial arrhythmias and the heart function of patients with sick sinus syndrome in different pacing modes.Such as AAI mode,DDD mode and VVI mode.In order to find the optimal pacing mode for the patients with sick sinus syndrome.Methods:20 patients with sick sinus syndrome were selected for the study during the period from June 2007 to January 2008 in Tianjin Chest Hospital.They were implanted DDD pacemakers.They were programmed short AV delay:pace AV130-150ms, sense AV 110-130ms after the operation.One week later,programmed the pacemakers again and found the percentage of ventricular pacing(VP%)＞50%.The levels of atrial natriuretic factor(ANP).plasma endothelin(ET),angiotensin(AngⅡ), ang aldosterone(ALD) were measured,programmed the AV delay to protect VP%is 100%,hemodynamic parameters were measured by Doppler echocardiography including the diastolic function:E peak.A peak,E/A.the duration of E peak,and the duration of A peak.the systolic function:aortic flow velocity time integral(AVTI), left ventricular ejection fraction,and the velocity of aortic,the parameters of asynchrony:aorta pre-ejection interval APEI,pulmonary artery pre-ejection interval PPEI,and calculated PPEI-APEI.measure the duration of QRS from start to the left ventricular lateral wall conduction and the duration of QRS from start to the ventricular septum conduction.and calculate the difference.after the exam.programmed the pacemaker again and prolong the PAV to 250 -300ms,SAV to 230 - 280ms,and the pacemaker is on atrial pacing -ventricular sensing mode(AP-VS),the QRS wave is thin.After 5 min.measured the factor again.follow-up was done after 2 weeks,the percentage of ventricular pacing(VP%) was＜1%,the levels 4of ANP,,ET,AngⅡ,ALD.were measured again.60 patients of SSS were selected during June 2007 to January 2008 in outpatient department.And the patients were divided into 3 groups:AAI group,DDD group and VVI group.the basic clinical criteria had no statistical difference of clinical.All patients underwented pacing for more than 1 year.The VP%of DDD group is more than 50%.Hemodynamic parameters were measured by Doppler echocardiography including the LVEF,diameter of left atrium and right atrium.The follow-up was down to monitor atrial arrhythmia and statistical analysis was done above mentioned parameters.Results:1 hospitalized patients(control groups)1.1 The level of plasma ANP,ET,AngⅡ,ALD in patients with DDD mode were higher than AAI mode and have statistical difference.ANP(0.14±0.04 vs 0.18±0.04 t=5.358 p?0.01):ET(86.06±25.33 vs 91.98±21.64 t=2.727 p＜0.05);AngⅡ(67.46±19.36 vs 74.82±10.92 t=2.102 p＜0.05);ALD(0.06±0.02 vs0.07±0.02t=3.812 p＜0.01). 1.2 The hemodynamic parameters changes at the time of adjustment:AVTI was higher in AAI mode than DDD mode and had statistical differences.(28.30±4.37 vs 27.23±4.02 t=4.413 p＜0.01) ventricular diastole(E+A) was shorter in DDD mode than in AAI mode.ventricular synchronism of the two chamber was larger in DDD mode than in AAI mode but have no statistical significance.The diameter of LA and LV.and LVEF has no statistical difference.The width of QRS was wider in DDD mode than in AAI mode(161.1±11.4 vs 95.0±14.0),and have statistical significance.(p＜0.05 )2 outpatient department patients(3 groups )2.1 the level of ANP,ET has the tendency to raise from AAI group to DDD group and to VVI group.and have statistical difference.2.2 the level of AngⅡ.ALD has the tendency to decrease from AAI group to DDD group and to VVI group,but have no statistical difference.2.3 The incidence of atrial fibrillation in 3 groups has statistical difference(X 2=8.125 p＜0.05).the incidence of atrial fibrillation has statistical difference between AAI group and VVI group(X2=7.025 p＜0.01).there is on statistical difference between the other groups.2.4 the diameter of LA and RA has the tendency to larger from AAI group to DDD group and to VVI group,and have statistical significance.Conclusion:1 The percentage of unwanted ventricular pacing may increase in patients with normal atrial-ventricular node conduction in DDD mode.Compared with AAI mode.the DDD mode will activate neuroendocrine,in short term and has adverse effect to hemodynamics.2 My study suggests that ventricular desynchronization imposed by right ventricular apical pacing resulted in adverse effect of the systolic and diastolic function.3 The percentage of atrial fibrillation will be lower if the AV and ventricular synchrony is preserved.And the atrial reconfiguration will be improved.4 The unnecessary ventricular pacing may resulted in the SSS patients with normal AV conduction after DDD pacemaker implanted with out AV delay adjustment.So my suggestion is AVD must be adjusted to optimal AVD.5 In patients with SSS and normal atrioventricular conduction AAI pacing mode is more physiological,simple,economy than other pacing mode and can avoid right ventricular apex pacing effectively.