echocardiography: systolic velocity V1/V2 ratio of aortic valve with stress
echocardiography: systolic velocity v1/v2 ratio of aortic valve with stress
echocardiography: systolic velocity V1/V2 ratio of aortic valve with stress (procedure)
echocardiography: systolic velocity v1/v2 ratio of aortic valve with stress (procedure)