Afterload is defined as what?

Afterload is defined as what?

• A. The force of ventricular contraction
• B. The heart rate
• C. The resistance to ventricular ejection of blood
• D. The amount of blood returning to the heart

Answer: (C)

Afterload is the pressure the ventricle must overcome to eject blood during contraction. It represents the resistance to ventricular ejection, coming from the arterial system (systemic vascular resistance and arterial pressure) and any impedance from the aortic or pulmonary valves. This is different from preload, which is the amount of blood returning to the heart, and from contractility, which is the force of the ventricular contraction itself. When afterload increases (as with hypertension or aortic stenosis), the heart has to work harder to push blood out, which can reduce stroke volume if contractility doesn’t compensate.

Afterload is the pressure the ventricle must overcome to eject blood during contraction. It represents the resistance to ventricular ejection, coming from the arterial system (systemic vascular resistance and arterial pressure) and any impedance from the aortic or pulmonary valves. This is different from preload, which is the amount of blood returning to the heart, and from contractility, which is the force of the ventricular contraction itself. When afterload increases (as with hypertension or aortic stenosis), the heart has to work harder to push blood out, which can reduce stroke volume if contractility doesn’t compensate.