Which equation expresses cardiac output in terms of SV and HR?

Study for the Echocardiography Techniques II Exam 2. Equip yourself with flashcards and multiple choice questions, each question comes with hints and explanations to prepare you for the test.

Multiple Choice

Which equation expresses cardiac output in terms of SV and HR?

Cardiac output is the volume of blood the heart pumps each minute, which depends on how much blood is ejected with each beat (stroke volume) and how many beats occur per minute (heart rate). Therefore CO = SV × HR, with HR in beats per minute and SV in mL per beat, giving CO in mL per minute (convert to L/min if needed). The extra factor of 60 would only apply if heart rate were expressed in per-second units, which isn’t the standard in this context. The expression involving velocity-time integral times cross-sectional area gives stroke volume, not cardiac output, unless you then multiply by heart rate. Dividing stroke volume by heart rate would give an incorrect relation, reducing the overall output.

Cardiac output is the volume of blood the heart pumps each minute, which depends on how much blood is ejected with each beat (stroke volume) and how many beats occur per minute (heart rate). Therefore CO = SV × HR, with HR in beats per minute and SV in mL per beat, giving CO in mL per minute (convert to L/min if needed).

The extra factor of 60 would only apply if heart rate were expressed in per-second units, which isn’t the standard in this context. The expression involving velocity-time integral times cross-sectional area gives stroke volume, not cardiac output, unless you then multiply by heart rate. Dividing stroke volume by heart rate would give an incorrect relation, reducing the overall output.

More practice questions