A hospitalized patient has an ejection fraction of 0.4, a hea rate of 95 beats/min, and a cardiac output of 3.5 L/min. What is the patient's end-diastolic volume?

First, calculate stroke volume from the cardiac output and hea rate: Cardiac output = stroke volume x hea rate; thus, stroke volume = cardiac output/ hea rate = 3500 mL/95 beats/min = 36.8 mL. Then, calculate end-diastolic volume from stroke volume and ejection fraction: Ejection fraction = stroke volume/end-diastolic volume; thus end-diastolic volume = stroke volume/ejection fraction = 36.8 mL/0.4 = 92 mL.