Cardiac Cycle and Hemodynamics · USMLE Step 1

Which of the following defines afterload for the left ventricle in most physiologic descriptions?

End-diastolic filling volume of the left ventricle
Arterial pressure and resistance opposing ejection
Intrinsic contractility of the cardiac muscle fibers
Venous return of blood into the heart

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Correct answer: Arterial pressure and resistance opposing ejection

Afterload represents the resistance the ventricle must overcome to eject blood, primarily determined by arterial pressure and vascular resistance during systole.

Difficulty: Medium Question 6 of 21

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