3.6 Hypertension + Heart Failure

Question 1

What is preload, afterload, and overload?

Answer 1

Preload = volume of blood in heart chambe during filling phase

Afterload = peripheral resistance to eject blood, dependent on BP + vascular tone

Volume overlaod = too much blood in heart chambers during preload

Question 2

How is normal blood pressure (120/80 mmHg) regulated?

Answer 2

Baroreceptor (and chemoreceptor) = short term

Renin-angiotensin system (RAS) = long term

Question 3

What is hypertension?

Answer 3

High blood pressure (>130/85 mmHg)

Increase in blood volume via RAS

Increase in vascular resistance (vessel diameter) via SNS OR atherosclerosis

Involves reset of baroreceptor

Question 4

What are the two types of hypertension and their unique characteristics?

Answer 4

1. Essential = no clear cause, removing risk factors may reduce pressure but NOT cure, 95% of all hypertension cases
2. Secondary = caused by another medical condition, usually cured if causational factor is removed, eg pregnancy

Question 5

What are the risk factors for hypertension?

Answer 5

Age, race, weight, and family history

Physcial inactivity

Smoking + alcohol

Diet (high salt or lacking potassium = activates RAS)

Stress + other conditions eg diabetes or high cholesterol

Question 6

Hypertension can cause damage to end organs due to both underlying disease conditions like atherosclerosis + high blood pressure. How does this happen?

Answer 6

High BP = vascular remodelling

Stiffness of wall = less elasticity + easy rupture

Vessel wall thinning

Damages endothelial lining = increase atherosclerosis

Question 7

All organs can be affected by hypertension and suffer end organ damage. However, what are the 4 most commonly affected organs?

Answer 7

1. Brain = stroke, both infarction + haemorrhage
2. Heart = left ventricular hypertrophy, heart failure, heart attack
3. Eye = haemorrhage, loss of eyesight
4. Kidney = failure (ischemic + aedemic changes = fibrosis)

Question 8

Heart failure occurs when the heart fails to circulate blood effectively. What are the consequences of this?

Answer 8

Not enough fresh blood = hypoxia + malnutrition in tissue = cells damaged + becomes fibrotic

Venous blood cannot return to heart = oedema in tissue + oragns

Cardiac hypertrophy = enlargement of heart due to compensatory attempt

Question 9

What are the two types of heart failure?

Answer 9

1. Right sided
2. Left sided

Question 10

75% of left sided congestive heart failure is due to MI + hypertension. What are the possible lasting consequences of left sided heart failure?

Answer 10

Lungs = pulmonary oedema (difficult to breathe)

Heart = eccentric hypertrophy from MI, concentric hypertrophy from hypertension

Peripheral tissue = Poor perfusion

Death = asphyxiation

Question 11

What are the possible lasting consequences of right sided heart failure?

Answer 11

1. Heart = hypertrophy / dilation
2. Systemic + generalised oedema = hepatomegaly, indigestion, ankle
3. Death = multi organ failure