Sustained left ventricular diastolic dysfunction following ischemia reperfusion injury in an acute myocardial infarction rat model

The aim of this study was to investigate cardiac function in a rat myocardial ischemia/reperfusion injury model during the early phase using echocardiography. Adult male Sprague-Dawley rats underwent myocardial ischemia and reperfusion (I/R) injury by ligation of the left anterior descending coronary artery (LAD). Echocardiography was performed at 2 hours, 24 hours, 3 days, and 7 days after the induction of myocardial infarction (MI). The ejection fraction (EF) and fractional shortening (FS), indexes that reflect left ventricular systolic function, of the MI group were significantly decreased compared with those of the sham group at 2 hours and on day 1 (P ＜ 0.01). To assess left ventricular (LV) diastolic dysfunction, we measured the peak velocity of the transmitral flow at early filling (E), the early diastolic mitral annular velocity (E’) at the medial mitral annulus and the E/E’ ratio. During the entire experimental period, the E’ values were significantly decreased and the E/E’ values were significantly increased in the MI group compared to the sham group. These results suggest that, unlike systolic function, diastolic dysfunction does not recover in the early phase of ischemic reperfusion injury in rats; this may be important for the development of effective therapies for acute MI. Moreover, this animal model and ultrasound-based assessment of cardiac function can be used in translational research and in the development of new heart failure drugs.