Study Of The Dependability Between Patent Ductus Arteriosus(PDA) And Left Ventricular Asynchrony

Background and objective Patent ductus arteriosus(PDA)is a frequent congenital heart disease,is about 2%in congenital heart disease case by autopsy and is about 18.5%in operation case,4.75%in liveborn infant.PDA can cause severe status in preterm infant,large patent ductus arteriosus may lead to enlargement of left auricle and left ventricular,congestive heart failure,repeatedly respiratory infection, developmental disorder and proceed pulmonary artery hypertension(PH)and so on. Arterial duct should close after foetus born,procedure of closure separate to two stage:1.medio-smooth muscle(SM)of Arterial duct contracts,causes to ductus short and wall thickness increasing,and intruding thickening intimal lumens to lead to functional closure,it usually takes place in 10h～15h after term infant born.2.Two stage closure is completed in 2～3w after term infant born,because endodermis forms plica,endomembrane underlayer accrementits and breaks,takes place small focus haemorrhage and necrosis,produces connective tissue and fibrosis,to make the ductus permanently close.If with various kinds patho-condition induce lumens cannot close,that is PDA.This kind of deform's main pathophysiology is left-to-fight shunt,at this time a part of blood what left ventricle(LV)rows to aorta in period of contraction of left ventricle enter to pulmonary artery by arterial duct, which is left-to-right shunt at artery level.Due to left-to-right shunt at artery level result in blood volume what pulmonary vein return to LA and LV increasing,preload of LV increases,stroke volume of LV increases.Because of working quantum of LV increasing,parieses of left ventricle thicken,cardiac muscle reconstitute,left chambers heart augment,which leads to left heart failure in the long time.Before studying cardiac ventricle synchronism by exterior and interior of state mainly concentrate on middle-age and senile patient,including inside ventricle derangement,inter-ventricle derangement,atria and ventricle derangement as well as resynchronization therapy.PDA patients mainly exist in premature infants,infants and young children,when they occur cardiac muscle reconstitution,chambers heart enlarge,and congestive cardiac failure,if wall motion of left ventricle synchronize and the relation with patency arterial duct,there is no any report exterior and interior. To assess myocardial asynchrony,the traditional methods of echocardiography are M-mode,color kinesis and so on.Because of a few sample sites and being dependent on two dimensional imaging,their use is limited.At present time,Doppler tissue imaging(DTI)provides us a simple and valuable method for assessing the myocardial asynchrony.The quantitative tissue velocity imaging(QTVI)is a new DTI method and can analyze many segments of myocardium simultaneously along long-axis of heart,having significant advantages in assessing myocardial asynchrony. However there is little similar study domestically yet.this study is to detect these index of myocardial synchronization of left ventricle by QTVI technology between unimpaired children and PDA patients,it's purpose is:1.To evaluate the LV synchrony in different segments of normal children and to find the factors related to the time of electromechanical systole and diastole of myocardium.2.To evaluate the LV asynchrony in different segments of patients with PDA.3.To evaluate the relation with the LV asynchrony and function of LV,remodeling of LV and mitral regurgitation and so on.Materials and methods twenty normal subjects(10 men,10 women),age 1～18 years,mean age(6.7±4.4)years;thirty patients with PDA(12 men,18 women),age 1～21 years,mean age(7.2±5.1)years.Clinical manifestation,case history,health examination,electrocardiogram(ECG),X-ray,ultrasonic cardiogram(UCG)and cardiac catheter contrast examination accord with cardiology diagnostic criteria of PDA,evacuating PDA with ventricular septal defect(VSD),atrial septal defect(ASD) and other cardiac anomalies,acute or subacute infective endocarditis, cardiopericarditis,heart valvular affection and serious hypertention(≥160/95mmHg)。Equipment apply for Philips iE33 color Doppler ultrasound machine by Philips corporation produced,detective head frequency is 2.0～4.0MHz, equipping with QTVI image quantitative analysis and postprocessing software,by left ventricle long-axis view,two-chamber view and four-chamber view from denom apex cordis position,taking DTI image from LV lateral,anteroseptal,posteroseptal, anterior,inferior and posterior segments at basal,middle and apical levels.The time from onset of QRS complexes to peak velocity during systole and diastole(Ts and Te) were measured.TS and Te represent the time of electromechanical systole and diastole of myocardium respectively.The maximal difference in Ts and Te with in the same wall(Intra-△Ts and Intra-△Te),the same segment(Inter-△Ts and Inter-△Te) and all 18 segments(Max-△Ts and Max-△Te)of LV were calculated. Parameters of LV function and the other measured Indexes included:1.Ejective fraction of left Ventricle(LVEF along apical four-chamber view by Simpson's equation);2.The mean of systolic peak velocities and early diastolic peak velocities of mitral annulus of six walls(Mean Vs and Mean Ve,along apical long-axis view, four-chamber view,two-chamber view by DTI);3.End diastolic diameter of left ventricle(LVEDD,along LV long-axis view by M-mode);4.End systolic diameter of left ventricle(LVESD,along LV long-axis view by M-mode);5.End diastolic volume left ventricle(LVEDV)and end systolic volume left ventricle(LVESV):along LV long-axis view or four-chamber view by M-mode;6.CO.Results1.Ts and Te with in the same segment and the same wall of LV had no significant difference in normal subjects(P＞0.05).Both Ts and Te were not significantly correlated with heart rate,age,systolic blood pressure,diastolic blood pressure and body surface area.2.Inter-△Ts,Inter-△Te,Intra-△Ts,Intra-△Te,Max-△Ts and Max-△Te in PDA group were significantly prolonged,compared with these parameters of the control group(P＜0.05 or P＜0.01).3.In PDA group,Max-△Ts was correlated with LVEDD,LVEDV,MeanVs (r=0.774,P＜0.01;r=0.589,P＜0.01;r=0.632,P＜0.05;respectively),but it was not correlated with LVEF,LVESD,LVESV,CO,BSA and QRS duration.Max-△Te was correlated with Mean Ve and MRA/LAA(r=0.559,P＜0.01;r=0.681,P＜0.01) and it was not correlated with LVEF,LVESD,LVESV,CO,BSA and QRS duration.Conclusions1.In normal persons,the time of electromechanical systole and diastole of myocardium within different segments of LV is same.The result illustrates that systole and diastole movement is highly synchronized in LV.2.Asynchorny exists within the same wall and the same segment of LV in patients with PDA.3.The parameters of asynchrony of myocardium movement have close relations with function of LV,mitral regurgitation and remodeling of LV with PDA.4.QTVI is a rapid,noninvasive,quantitative method to detect systolic and diastolic asynchrony;it is very useful to evaluate the clinical treatment of PDA.