Assessment of left ventricular systolic function using contrast two-dimensional echocardiography with a high-frequency transducer in the awake murinemodel of myocardial infarction

The estimation of global left ventricular function using M-mode echocardiog raphy has technical limitations in the murine model of myocardial infarctio n (MI), but the recent improvements in 2-dimensional (2-D) echocardiography using a high-frequency transducer provide more accessible images. Furtherm ore, intravenous injection of contrast agent has the additional benefit of enhancing the endocardial border in the murine heart. The present study was designed to evaluate the value of 2-D echocardiography with intravenous in jection of contrast agent in the assessment of global systolic function of the murine heart with MI. Two-dimensional and M-mode echocardiography witho ut and with intravenous injection of contrast agent (Optison, 0.1-0.15 ml) were performed in 76 awake mice 2 days before and 2 days after left coronar y artery ligation. Fractional shortening (FS) was calculated from the end-d iastolic and end-systolic diameters on M-mode echocardiography, and fractio nal area change (FAC) from the end-diastolic and end-systolic areas on 2-D echocardiography. Both FS and FAC were compared with the areas of hypoperfu sion observed in the pathological samples. The use of contrast agent improv ed the number of hearts that could be evaluated by both the M-mode and 2-D method (M-mode: non-contrast 87% vs contrast 99%, p<0.01; 2-D: non-contrast 26% vs contrast 89%, p<0.001). FAC from the 2-D method correlated better w ith the region of hypoperfusion in the pathological samples than did FS fro m the M-mode method (FAC: r=0.84 vs FS: r=0.51). In conclusion, FAC obtaine d from 2-D contrast echocardiography is useful for noninvasive assessment o f global systolic function in infarcted murine hearts and can be used to se rially assess systolic function in various models of the murine heart.