16. Cardiac Output and Contractility

Question 1

What does decreasing afterload do to the velocity of ventricular contraction?

Answer 1

Increases velocity

Question 2

What is the equation for stroke volume?

Answer 2

SV = End Diastolic Volume - End Systolic Volume

Question 3

What is the equation for ejection fraction

Answer 3

Ejection Fraction % = Stroke Volume / End Diastolic Volume

Question 4

What is the equation for cardiac output?

Answer 4

Cardiac Output = Stroke Volume * Heart Rate

Question 5

What is the normal ejection fraction?

Answer 5

55%

Question 6

What would and increase in preload do to the stroke volume?

Answer 6

Increased preload increases stroke volume

(Frank-Starling principle)

Question 7

What does an increase in afterload reduce in terms of the pressure / volume loop?

Answer 7

Stroke volume

Question 8

What does an increased chronotropic effect do to contractility, assuming the ventricles have time to fill?

Answer 8

Increases contractility