Heart Failure Flashcards
What is congestive heart failure (CHF)?
- Progressive condition
- Damage to one or both ventricles affects ability to maintain cardiac output
Pulmonary oedema is a cardinal sign of CHF, involving, primarily, the left ventricle. Use your understanding of Starling’s principle of fluid exchange to suggest how left ventricle failure leads to pulmonary oedema.
- Less blood pumped out of the heart ∴ less cardiac output
- Accumulation of fluid in the lung area ∴ hydrostatic pressure in vessels increases
- More fluid released from the vessels, causing pulmonary oedema.
Peripheral oedema (eg. legs, feet) is often present with right or biventricular failure. Explain. PART 1
- Right ventricle cannot pump efficiently to the lungs ∴ reduced volume of blood that becomes oxygenated
- Build-up of blood in the veins/capillaries ∴ increase in hydrostatic pressure.
Peripheral oedema (eg. legs, feet) is often present with right or biventricular failure. Explain. PART 2
- Increase in hydrostatic pressure overcomes the osmotic pressure and favors filtration into the interstitial fluid, causing oedema.
Hypertension is a risk factor for CHF. Explain how long-term hypertension may lead to an increased blood volume.
- Hypertension - an increase in blood pressure. Pressure in arteries rises
- Greater pressure required within the ventricles to open the aortic valve.
- To increase pressure, blood volume would also need to be increased.
How does this increase in blood volume lead to heart failure? Refer to Laplace’s Law. PART 1
- Greater volume in the ventricles ∴ radius of the ventricles increases.
- Greater wall stress.
- Increased afterload, and the heart has to pump harder in order to get the blood out of the chamber.
How does this increase in blood volume lead to heart failure? Refer to Laplace’s Law. PART 2
- Greater strain on the heart, causing enlargement of the heart - hypertrophy. This can progress to heart failure due to continuous contraction of heart.
