Assessment Of Systolic Left Ventricular Transmural Mechanics Using Quantitative Tissue Doppler Image Ultrasongraphy In Vivo: A Normal Canine Model

ObjectiveTo assess the myocardial segmental globe and the transmural segment peak radial strain(RS-peak) and peak time(T-peak) of left ventricular in physiological conditions,to quantitatively analyse the myocardial mechanical characteristics and correlations about the globe and transmural myocardial segment, to discover defor- mation characteristics and systolic sequence in time in systolic.MethodsIn the 10 open-chest Beagle canine models , the standard short-axis views of 2-D tissue Doppler imaging(TDI) at the levels of mitral annulus(MV), papillary mus- cle(PW) and apical level(AP) in three cardiac cycles were acquired. Using quantify- cation tissue doppler imaging (TDI-Q) workstation,strain-time curves were obtained about Anterior wall(AW),interseptal wall(IS),posterior wall(PW) and lateral wall(LW)of the myocardial segmental globe,all of 12 segments,and subendocaridium (subendo), medium(mid), subepicaridiums(subepi) the transmural three myocardiums ,and RS- peak and T-peak of the different segmental globe and segmental transmural myocardium were calculated.Results1. At the levels of PW and AP,the RS-peak of the PW is higher than the other segments(P<0.05).2. All segments,the RS-peak of subendocaridiums(subendo)was higher than subepicaridiums(subepi).At the level of PW,the RS-peak of mediums(mid) was higher than subepis. At IS of PW and AP , the RS-peak of subepis were negative.The RS-peak of subendo was the highest at the LW of the AP(P<0.05).3. In AW of MV,IS of PW,LW of PW,AW of AP,IS of AP,IW of AP,PW of AP,it had the correlation between subendo,mid,subepi and the segmental globe.4. The peak time of all segments were observed.It was the earliest in the AW and IS of PW and the latest in the IW and PW of AP. It was the earliest in the subendo, and the latest in the subepi.The subepi of AP was the latest.ConclusionThe myocardial segmental globe and the transmural segment peak radial strain (RS– peak) and peak time (T-peak) of left ventricular were dyssynchrony. The RS-peak of LW was the highest,and T-peak of LW was the latest. RS-peak was gradually increasing, and T-peak was gradually reducing from the suendo to the subepi. It had the correlation between subendo,mid,subepi and the segmental globe,and it had the highest correlation between mid and the segmental globe.