ABSTRACT
Objective To study the influence of different microembolism on left ventricular systolic synchronism in pigs by detecting the real-time dypyridamole stress contrast echocardiography (RT-MCE).Methods Eighteen miniature pigs were randomly divided into three groups and underwent microembolization injection procedure through the middle of anterior descending coronary artery with different numbers of microsphere injection,as:group A(dosage 50 thousands,3 pigs),group B (dosage 120 thousands,8 pigs) and group C (dosage 150 thousands,7 pigs).The peak values and the time-to-peak circumferential strain(Circ.Strain),radial velocity (Radial Vel.) and radial strain (Radial Strain) were obtained both at mitral valve level and papillary muscle level at left ventricle short axis views using two-dimensional speckle tracking imaging(STI)analyzed by Philips Q-Lab 8.1 workshop,respectively.Results No significant difference in the presence of contraction synchrony was observed using RT-MCE.The time-to-peak Circ.Strain of microembolism related segments were prolonged at 1 week after microembolism detecting with dypyridamole stress RT-MCE (P＜0.05,both intro-group and inter-group).While time-to-peak radial strain were extended since 6 hours after the intervention to 1 week after the procedure.Conclusions Dypyridamole stress RT-MCE can be used to measure the myocardial perfusion accurately.The elongation of time-to-peak circ.strain and radial strain were developed with time in microembolism related segments.
ABSTRACT
Objective To compare the effects of different doses of adenosine(AD)on the left coronary blood flow(CBF)and left coronary flow reserve(CFR)in mini-swine.Methods By using Doppler flow wire and intracoronary ultrasound imaging catheter at the middle segment of LAD,coronary average peak flow velocity(APV)and lumen area were measured in 10 healthy mini-swines.CBF was calculated from the equation of 0.6 APV times 0.5 lumen area.Intracoronary bolus injection of different dose AD(12μg,18μg,24 μg and 36μg,separately)was used to induce maximal coronary hyperemic reaction.CFR was defined as the ratio of hyperemic CBF to resting CBF.Results Intracoronary bolus injection of 18μg AD level induced a maximal coronary vasodilation.Significant difference in the hyperemic CBF existed between 12 μg AD dose and 24μg or 36μg AD dose(P＜0.05).No significant difference in heart rate,blood pressure,rCBF and CFR was found among three different AD dose groups(18μg,24μg,and 36μg).Conclusion CBF and CFR in mini-swine can be effectively assessed by bolus injection of AD with the dose of(18～24)μg.