Study Of Optimization Of Cardiac Resynchronization Therapy And Its Application, Evaluation By Echocardiography

OBJECTIVE To explore the value of evaluating and Optimizing to cardiacresynchronization therapy(CRT) by echocardiography, and find out the key echocardiograpicparameters of optimizing cardiac resynchronization therapy and its methodology.METHOD The study subjects consists of 23 inpatients with congestive heart failurefrom April 2004 to March 2006 in the first affiliated hospital of Kunming MedicalCollege.19 of them with cardiomyopathy (dilated 15,ischemic 3,alcoholic 1) hypertensiveheart disease 3,and one rheumatic valvular disease.The duration of CRT 1-3 years,patientswere divided randomly into two groups,the optimized atrioventricular delay (AVD)group(n=17) and non-optimized AVD group (n=6) as control.Seven patients in optimizinggroup,at the same time ,received interventricular delay (VVD) optimization. AV delayoptimization was firstly programmed at 80ms,100ms,120ms,140ms,160ms and 180ms,comparing echocardiographic immediate parameters difference measured at all AV intervalsand the optimzed was set. 6 mouths later, the echocardiographic and clinical parameters ofthe two group patients were follow up and compared intergroups and intragroup. Then, afterreceiving AV delays optimization, we make 7 patients from the optimized group receive VVdelays optimization in order to compare the immediate differences of echocardiographicparameters at different VV intervals. Echocardiographic parameters include: left ventricularend diastolic volume(LVEDV), left ventricular end systolic volume (LVESV), left ventricleejection fraction (LVEF), Tei index(Tei), The maximal first derivative of left ventricularpressure (dp/dt), mitral regurgitant orifice area(MV-EROA), mitral regurgitant volume(MV_-RV),mitral velocity-time integral (VTI_Mv), left ventricle filling time(LVFT), aortic velocity-timeintegral(VTI_AV), aortic velocity-time (AV_TIME),left-right ventricle pre-ejection time delay(PET_d),standard deviation of the time to peak of systolic velocity(TS-SD), Tissuesynchronization imaging (TSI), post systolic shortening(PSS). Clinical parameters include: 6-Minute walk distance test (6MWT), Minnesota's quality of life score(QOL), New YorkHeart Association (NYHA) functional classification, and following up visit observation.RESULTS In optimized group ,the optimzed AV delay ranged from lOOms tol40ms.theindividual variability ranging from 80-160ms is considerably obvious. The optimized AVdelay parameters improved immediately, LVFT, VTI_-Mv,VTL_-AV,dp/dt and EF increased, andMV_-EROA and Tei index decreased(P＜0.05). In optimizing group, following up 6 months ofAV delay post-optimization was associated with a further increase in EF and dp/dt, decreasein Tei index , and improvement NYHA classification and 6-min walk test(eachp＜0.05)compared immediate of AV delay post-optimization, while in control group, only Teiindex reduced, the variability of 6MWT,EF,Tei indexe and dp/dt between 6 months andimmediate AV delay post-optimization in optimized group is superior to that of controlgroup's(p＜0.05).7 patients performed with VV delays optimization demonstrated that LVpre-activation was superior to simultaneous and RV pre-activation. Under such condition,Tei index, PET_d,TDI-SD,PSS decreased and dp/dt,VTI_AV increased(p＜0.05), EF alsoincreased but non significant.There was no obvious difference between simultaneous pacingand RV pre-activation measured by echocardiography.(p＞0.05).LV pre-activation delayranged from 10ms to 30ms, but there was individual variability.CONCLUSION CRT patients performed optimization of AV and VV delays under thesupervision of echocardiography obtained immediate and chronic improvement ofhemodynamic and clinical parameters.It is useful to optimize CRT system dynamically, andmay become a important means that improve CRT treatment and have a good future.