Pathophysiology of Heart Failure

Question 1

Define “pre-load”

Answer 1

The pressure in the ventricle before it starts to contract

Question 2

Define “after-load”

Answer 2

The pressure against which the heart has to eject blood

Question 3

Define “diastole”

Answer 3

Part of cardiac cycle where heart refills with blood after systole

Question 4

Define “systole”

Answer 4

Part of cardiac cycle where heart contracts following refilling

Question 5

Describe Starling’s Law of the Heart

Answer 5

The more you load the heart with blood, the harder it will work

Question 6

What is Diastolic Heart Failure?

Answer 6

When the heart can’t fill enough blood prior contraction

Question 7

What is Systolic Heart Failure

Answer 7

When the heart has a reduced force of contraction

Question 8

Left sided heart failure is usually caused by Systolic failure. Give some underlying pathologies of this

Answer 8

Usually Systolic failure:

• Damage to myocardium in Ischaemic heart disease (reduced force of contraction)
• Long standard HTN causing Left Vetricular Hypertrophy, causing increased O2 demand but compressed coronary arteries (reduced contraction)
• Dilated cardiomyopathy, whereby chamber enlargement grows to accommodate pre-load but is non sustainable

Question 9

Left sided heart failure can be caused by Diastolic failure - how?

Answer 9

• Long standing hypertension, can cause Left ventricular hypertrophy which causes reduces room in chamber for ventricular filling

Question 10

Right sided heart failure is mainly caused by Left sided heart failure. But what are some other causes?

Answer 10

• L to R cardiac shunt, i.e. in ASD or VSD, which means right ventricle receives high pressure blood and causes Hypertrophy. Can lead to Ischaemia (systolic dysfunction) and Smaller volume of heart (diastolic dysfunction)
• Chronic Lung Disease