How is cardiac output calculated?

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Multiple Choice

How is cardiac output calculated?

Cardiac output is the amount of blood the heart pumps per minute, determined by how often the heart beats and how much blood is ejected with each beat. The amount ejected per beat is the stroke volume, which equals end-diastolic volume minus end-systolic volume. Multiply heart rate (beats per minute) by stroke volume (mL per beat) to get cardiac output (mL per minute): CO = HR × SV. For example, with a heart rate of about 70 beats per minute and a stroke volume of about 70 mL per beat, CO ≈ 4900 mL/min (roughly 5 L/min). The other expressions don’t match the units or the physiological meaning: adding HR and SV would be incorrect, EDV − ESV gives stroke volume, and SV divided by HR would not yield a flow rate.

Cardiac output is the amount of blood the heart pumps per minute, determined by how often the heart beats and how much blood is ejected with each beat. The amount ejected per beat is the stroke volume, which equals end-diastolic volume minus end-systolic volume. Multiply heart rate (beats per minute) by stroke volume (mL per beat) to get cardiac output (mL per minute): CO = HR × SV. For example, with a heart rate of about 70 beats per minute and a stroke volume of about 70 mL per beat, CO ≈ 4900 mL/min (roughly 5 L/min). The other expressions don’t match the units or the physiological meaning: adding HR and SV would be incorrect, EDV − ESV gives stroke volume, and SV divided by HR would not yield a flow rate.

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