Experimental Research on the Evaluation of Left Ventricular Function by Layered Speckle Tracking in a Constrictive Pericarditis Rat Model.

Abstract

In animal models with constrictive pericarditis (CP), detecting the function of cardiac systole by conventional noninvasive ultrasound is a challenge. We aimed to detect cardiac dysfunction in rat models with CP in the early stage by layered speckle tracking. We compared a rat CP model (n = 23, injected with a solution of 1-mg/mL lipopolysaccharides [0.5 mL] and a 10% talc suspension [0.5 mL]) with a control group (n = 20, no injection). After 8 weeks, conventional echocardiography and layered speckle tracking were used to assess the left ventricular structures and functions in the groups. The global circumferential strain (CS) and longitudinal strain (LS) were decreased in the CP group (P < .05). The CS of the epicardial and middle layers in the CP group was decreased (P < .05), but the endocardial layer was not statistically different. The LS of the epicardial layer was decreased (P < .05), but the middle and endocardial layers were not statistically different. The global free-wall and septal-wall CS of the CP group was decreased (P < .05), mainly due to the decrease of CS of the epicardial and middle layers. The global free-wall LS of the CP group was decreased (P < .05), mainly due to the decrease of LS of the epicardial and middle layers. There were no significant differences between the groups in global LS of the septal wall. In the early stage of CP, subepicardial myocardial damage precedes that of the subendocardial myocardium, and free-wall damage precedes that of the septal wall.