Novel Rat Model of Ischemic Cardiomyopathy Induced by Repetitive Myocardial Ischemia/Reperfusion Injury While Conscious

Background A rodent model of ischemic cardiomyopathy (ICM) induced by repetitive brief ischemia/reperfusion (I/R) injury while conscious has not been previously established. Methods and Results A newly developed coronary occluder was implanted in male Wistar rats. A repetitive I/R protocol (20 s, 2 min, followed by main 30 min - ischemia, every 48 h, for 4 weeks) was introduced while the animals were conscious. The I/R protocol did not induce transmural scar formation but induced (1) residual myocytes with scattered infiltration of fibrosis (Masson trichrome stain), (2) coronary hypoperfusion (201Tl-Cl autoradiogram), (3) reduced coronary microvascular volume fraction (microCT), and (4) gradually progressive left ventricular (LV) dilation (echocardiography). These parameters of ICM showed interindividual variation; however, the percent increase in LV diastolic area on day 3 was significantly correlated with LV dilation (r=0.91, p