L12 Cardiac Function

Question 0

Diastolic heart failure

Answer 0

Failure to perform in diastole; heart has a very low compliance. This inhibits the heart from properly relaxing and properly filling, which affects the CO

Muscle is stiff (MI) or is not relaxing all the way

Question 1

Systolic heart failure

Answer 1

This is a problem with systole; when the heart is contracting. Systolic heart failure relates to problems with contractility and therefore Ca handling

Question 2

Ejection Fraction

Answer 2

The fraction of blood that leaves the ventricle compared to what enters.

EDV-ESV/EDV

NOT CO. This refers to a fraction, and implies whether or not blood is left behind.
Normal EF of 60% means that 40% of blood is left behind upon ejection (this would be the ESV)

Question 3

what affects preload?

Answer 3

anything that affects filling:

ventricular filling time, HR, less compliance, less atrial kick, less blood in the body

Question 4

What affects afterload?

Answer 4

high blood pressure, stenosis, dilated heart

Question 5

What affects contractility?

Answer 5

increased HR, sympathetic nerve activity, drugs (pos. inotropes), damaged tissue is less contractile

Question 6

Pressure-Volume Diagram of the Heart

Answer 6

more preload = more shortening
more afterload = less shortening
more contractility = more shortening

more shortening = more stroke volume = faster velocity