Echocardiogram: how can i have a 55-60% ejection fraction with a 37 ml stroke volume?

Diastolic heart fail: In constrictive heart diseases (like constrictive cardiomyopathy, pericarditis, diastolic dysfunction, & hypertensive heart diseases), the heart fails to relax in diastole to bring enough blood to the left ventricle. In that situation, you may be only getting about 70 mL in the LV, so an ejection fraction of 55-60% (which is "normal") only puts out about 37 mL (as opposed to 140 mL in, 70 mL out).