The effects of acute coronary occlusion on noninvasive echocardiographically derived systolic and diastolic myocardial strain rates

Purpose To compare the magnitude and rates of change of peak systolic (ε^′_SYS) and diastolic (ε^′_DIAS) strain rates, as measured using tissue Doppler echocardiography, to pressure and volumes left-ventricular indices during acute coronary occlusion. Methods Six closed-chest dogs had a combination high-fidelity conductance pressure transducer placed into the left ventricle for determination of end-diastolic and end-systolic pressures (EDP and ESP) and volumes (EDV, ESV, and ejection fraction [EF]). Other indices included the time constant of left-ventricular relaxation (τ), +dP/dt_max, -dP/dt_max, end-systolic pressure/volume index (ESPV). A coronary angioplasty catheter was positioned into the left-anterior descending coronary artery. During coronary occlusion, strain rates and hemodynamic parameters were recorded continuously for 2 minutes. Results During occlusion, significant decreases in strain rates occurred within 30 seconds. Systolic indices (ESPV and +dP/dt_max) changed at rates similar to ε^′_SYS (each p = NS). Diastolic indices (τ, EDP, EDV, -dp/dt_max) also changed at rates similar to ε^′_DIAS (each p = NS). However, EF decreased at a significantly slower rate than did strain rates (p < 0.05). CONCLUSIONS: Peak systolic and diastolic strain rates decrease with acute ischemia similar to corresponding indices of left-ventricular systolic and diastolic function. Strain rates may be used in the noninvasive assessment of ischemic-induced left-ventricular dysfunction.