Noninvasive monitoring of cardiac function in a chronic ischemic heart failure model in the rat: Assessment with tissue Doppler and non-Doppler 2D strain echocardiography

OBJECTIVES: Feasibility of noninvasive monitoring of cardiac function after surgically induced ischemic cardiomyopathy with tissue Doppler and non-Doppler 2D strain echocardiography in rats. BACKGROUND: The optimal method for quantitative assessment of global and regional ventricular function in rats with chronic heart failure for research purposes remains unclear. METHODS: 20 rats underwent suture ligation of the left anterior descending coronary artery via a left thoracotomy to induce ischemic cardiomyopathy. Echocardiographic examination with estimation of left ventricular wall thickness, diameters, fractional shortening, ejection fraction, wall velocities as well as radial strain were performed before and 4 weeks after surgery. RESULTS: Mean LVEF decreased from 70 ± 6% to 40 ± 8% (p < 0.0001) one month after the operation. LVEDD increased from 7 ± 1 mm to 9 ± 1 mm (p < 0.0001), systolic anterior velocity decreased from 0.79 ± 0.25 cm/s to 0.18 ± 0.19 cm/s (p < 0.0001). Radial 2D strain was significantly reduced after myocardial infarction of the septal (18.2 ± 6.6% vs 7.0 ± 5.9%, p < 0.001), anteroseptal (17.3 ± 5.2% vs 4.6 ± 3.0%, p < 0.0001), anterior (18.9 ± 5.9% vs 5.6 ± 2.5%, p < 0.0001), lateral (21.4 ± 4.9% vs 8.1 ± 3.5%, p < 0.0001) as well as posterior myocardial segments (19.3 ± 5.2% vs 15.4 ± 5.5%, p < 0.01). Inferior segments (19.2 ± 7.9% vs 17.8 ± 7.9%, ns) did not change at all. CONCLUSION: It is feasible to assess dimensions, global function, and regional contractility with echocardiography in rats suffering from chronic heart failure after myocardial infarction. Particularly regional function can be exactly evaluated if tissue Doppler and 2D strain is used.