Evaluation Of Left Ventricular Systolic Function In Dogs With Radiation-induced Heart Disease By Two-dimensional Speckle Tracking Imaging

Objective:(1)The longitudinal and circumferential systolic functions of the left ventricle in RIHD animal models were evaluated by two-dimensional speckle tracking imaging at different times before and after irradiation.(2)To observe the difference of routine echocardiography parameters before and after irradiation in RIHD animal model.(3)To evaluate the echocardiographic parameters sensitive to left ventricular systolic function in patients with radioactive heart injury.Methods:Echocardiography was performed on 6 male beagles 1 week before irradiation and 1,3 and 6 months after irradiation(20 Gy at a single time).Before and after irradiation,conventional echocardiography was used to measure the thickness of ventricular septum(IVS),left ventricular posterior wall(LVPW),left ventricular end-diastolic diameter(LVEDD),left ventricular end-systolic diameter(LVESD)and the calculated left ventricular end-diastolic volume(LVEDV),left ventricular end-systolic volume(LVESV),and left ventricular ejection fraction(LVEF).Collect and store the left ventricular apex long axis two,three,four four-chamber view and mitral valve,papillary muscle and apex level left ventricular short axis plane for two consecutive images of the cardiac cycle,QLAB offline application software is analyzed,respectively,according to the basal,middle section,apex section analysis interval before and after the interval,lateral wall and back wall and lower wall,front wall strain,a total of 18 section,peak longitudinal and circumferential strain measuring each segments,and at the same time get left ventricular overall longitudinal and circumferential strain of the left ventricle in various aspects.The global and local systolic functions of left ventricle were compared before and after irradiation.Results:(1)Compared with before and after irradiation,IVS,LVPW,LVEDD,LVESD,EDV,ESV and LVEF of RIHD animal models showed no significant changes at 1month?3months?6 months after irradiation(all P > 0.05).(2)The longitudinal strain peaks of myocardial segments before and after irradiation in RIHD animal model were compared.Compared with that before irradiation,the radial strain peaks of basement segment of lower wall,middle segment of ventricular septum and anterior parietal apex segment were all different(P<0.05).6 months after irradiation,the longitudinal strain peak of anterior parietal apex segment decreased compared with that before irradiation,and the difference was statistically significant(P<0.05).(3)Comparing the overall myocardial longitudinal strain of each section before and after irradiation in RIHD animal model,there were differences in 2C-GLS ?4C-GLS and LV-GLS compared with that before irradiation(P<0.05).At 6 months after irradiation,2C-GLS decreased compared with that before,1 month and 3 months after irradiation(P<0.05).(4)RIHD animal models before irradiation,different time after each segment myocardial circumferential strain peak,compared with before irradiation,illuminate the first wall wall of basement under each section,the peak period of circumferential strain differences(P<0.05),and 6 months after irradiation front wall apex peak period of circumferential strain before irradiation and irradiation after 1 month,3 months after irradiation,the difference was statistically significant(P <0.05).(5)Compared with that before and after irradiation,B-GCS and A-GCS of theRIHD animal model were different in terms of the overall peripheral strain of myocardium at different time points(P<0.05).A-GCS at 6 months after irradiation was significantly lower than that before,1 month after,and 3 months after irradiation(P<0.05).Conclusion:2DSTI can objectively and quantitatively evaluate the left ventricular systolic function of RIHD,and LS,CS,2C-GLS and A-GCS can be used as early monitoring indicators of RIHD.