echocardiography: pre-ejection period (PEP) of aortic valve at rest
echocardiography: pre-ejection period (pep) of aortic valve at rest
echocardiography: pre-ejection period (PEP) of aortic valve at rest (procedure)
echocardiography: pre-ejection period (pep) of aortic valve at rest (procedure)