Abstract P2129: Myocardial Stunning Model in Rats

Background: Myocardial stunning is a temporary loss of contractility without irreversible histological damage. In myocardial infarction(MI), stunning could lead to acute ischemic heart failure (AIHF). We aim to establish a model of myocardial stunning in rats. Methods: Rats were randomized to either two 5 min cycles of preconditioning(PC) or non-preconditioning (NPC) before ligating LAD for 13.5 min. Echocardiography (ECHO) derived wall motion score index (WMSI). Speckle tracking assesed heart function. TTC staining determined infarction size Results: PC-13.5 yielded akinesia at 4h and recovery at 48h by WMSI. Speckle tracking showed a worsening in LVEF, global longitudinal strain (GLS), and time to peak radial strain (TP) in the ischemic segment at 4h which normalized at 48h. In NPC-13.5 at 48h, LVEF, GLS, and TP radial strain didn′t recover. TTC staining showed minimal necrosis in PC and substantial necrosis in NPC. Conclusion: The study characterized a reproducible model of myocardial stunning. ECHO showed a human-like course of myocardial stunning. TTC showed absence of irreversible damage.