| Background :chronic cardiac failure is one of primary cause to angiocardiopathy death. Left ventricular mechanical dyssynchrony is frequently observed in chronic heart failure patients,which has a close correlation with prognosis of the patients. Large clinical trials have demonstrated that CRT can retrieve the mechanical dyssynchrony in patients, and improve heart failure symptoms, heart function,and left ventricular remodeling associated with a reduction in rehospitalization for heart failure and death rate.Despite enthusiasm of giving this therapy to patients who fulfilled the current recommendation(New York Heart Association functional class III or IV, Left ventricular end diastolic diameter≥55mm,left ventricular ejection fraction<35% and a widened QRS complex>120ms),nonresponse was observed in about one-third of patients.Recent studies have suggested the vital role of assessing systolic asynchrony by echocardiography to predict effect of CRT. Real time three-dimensional echocardiography is a novel technique currently being investigated in the evaluation of left ventricular contraction synchrony.Objective1.To evaluate the prevalence of dyssynchrony in patients with different degree of LVEF decrease using Real-Time Three-dimensional echocardiographic technique .2.To assess the short-term effects of cardiac resynchronization therapy by real-time three-dimensional echocardiogrphy.3.To study the effects of cardiac resynchronization therapy in patients with heart failure of different etiology by real-time three-dimensional echocardiography.Methods1.The results of regional volume curves in fifty patients with different degree of LVEF decrease (30 with LVEF<35%,20 with 35%≤LVEF<45%) were analyzed and compared on RT3DE. The mean systolic dyssynchrony index (SDI) of more than 8.3% was considered a marker of intraventricular dyssynchrony.2. Eighteen congestive heart failure patients with mechanical dyssynchrony determined by tissue Doppler imaging were enrolled.Philips IE33 with X3-1 probe was used to perform full volume real-time three-dimensional echocardiography(RT-3DE)before and one month after CRT.The global and 17-segmental volume curves(VTCs) were obtained by the on-line Qlab software.The end diastolic volume(EDV),end systolic volume(ESV),left ventricular ejection fraction(LVEF),the dispersion of time to minimum regional volume for 16,12 and 6 left ventricular segment(Tmsv16-SD,Tmsv12-SD and Tmsv6-SD) were recorded,and the maximum difference of time to minimum regional volume for16,12 and 6 left ventricular segment(Tmsv16-Dif,Tmsv12-Dif and Tmsv6-Dif ).The short–time changes of these parameters were investigated.3. Eighteen patients(13 men and 5 women,mean age 58.8±11.8 years)with New York Heart Association(NYHA)classⅢorⅣreceived cardiac resynchronization therapy from Nov. 2006 to Aug. 2007.Among them,two groups were divided according to the etiologies of heart failure:idiopathic dilated cardiomyopathy group(n=11)and non-idiopathic dilated cardiomyopathy group(n=7).All the patients enrolled fulfilled the criteria of left ventricular end-diastolic dimension(LVEDd)> 55 mm ,left ventricular ejection fraction(LVEF)< 30% and QRS duration≥120 ms.Their heart function were evaluated before the pacemaker implantation as well as 1-month and 3-month after the operation by real-time three-dimensional echocardiography.The follow up period was 3～10 months.Results1.Dyssynchrony was observed in 4 (20.0%) with patients with 35%≤LVEF < 45% versus 21(63.9%)patients LVEF < 35%,and a significant difference was found between the prevalence of dyssynchrony derived from echo criteria in two groups(P<0.01). There were remarkably difference in standard deviation(SD)and maximal difference (Dif) of the time to point with minimal systolic volume(Tmsv)of 16 segments,12 segments (6 mid and 6 basal)and 6 segments (basal) in two groups ,P |
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