9. Heart Failure

Question 1

Define heart failure.

Answer 1

A state in which the heart fails to maintain an adequate circulation to meet the needs of the body.

Question 2

What is the primary cause of HF?

Answer 2

Ischaemic heart disease - atheromatous plaque in coronary arteries

Question 3

What 4 things affect cardiac output?

Answer 3

1. Myocardial contractility - muscle function
2. Venous capacity - preload
3. Afterload - hypertension increases impedence
4. Heart Rate - slight increase is more efficient but too fast decrease efficiency.

Question 4

How does Starlings curve change in patients with severe HF?

Answer 4

Reduced contractility
Once past a certain point, increased filling doesn’t increase CO and it begins to decrease.
If filling too great -> oedema, dilation and worsened symptoms

Question 5

What pathological changes occur in LV systolic dysfunction?

Answer 5

Thinning of myocardial wall
Dilitation - mitral valve incompetence
Neuro-hormonal activation
Risk of cardiac arrythmias

Question 6

The SNS is activated in HF, how does this cause deleterious effects in the long term?

Answer 6

• Activates RAAS
• Increased HR and contractility leads to LV hypertrophy
• Vasoconstriction
• Direct cardiotoxicity causes myocyte damage

Question 7

Which angiotensin receptor is responsible for inducing organ damage?

Answer 7

AT1 receptor

Question 8

Why is RAAS commonly activated in HF?

Answer 8

1. Reduced renal blood flow

2. SNS induction of renin

Question 9

Which molecule is detected in blood tests to aid diagnosis of HF?

Answer 9

BNP - elevated in HF

Question 10

What type of HF is associated with peripheral oedema?

Answer 10

Right-sided

Question 11

What type of HF is associated with pulmonary oedema?

Answer 11

Left-sided

Question 12

How does R-sided HF lead to peripheral oedema?

Answer 12

Back log from RA increases capillary hydrostatic pressure.

Question 13

What is HF with preserved ejection fraction?

Answer 13

Reduced LV compliance and impaired myocardial relaxation.

• Thicker and shorter cardiomyocytes
• Increased deposition of collagen

Question 14

What is impaired in HF with preserved ejection fraction?

Answer 14

Diastolic filling of LV - increased LA and PA pressure

Can lead to RV dysfunction

Question 15

What symptoms are associated with L-sided HF?

Answer 15

fatigue, exertional dysoneoa, orthopnea, paroxysmal nocturnal dyspneoa

Question 16

What clinical signs may appear as LVSD progresses?

Answer 16

Tachycardia
Cardiomegaly - displaced apex beat
Basal pulmonary crackles
Peripheral oedema

Question 17

What are common causes of R-sided HF?

Answer 17

• Congestive lung disease
• Pulmonary embolism/hypertension
• L to R shunts
• Most frequent cause is secondary to left HF

Question 18

What are the symptoms and signs of R-sided HF?

Answer 18

Fatigue, dyspneoa, anorexia, raised JVP, hepatic enlargement, putting oedema, ascites, pleural effusion

Question 19

What is the name given to isolated HF due to lung disease?

Answer 19

Cor pulmonale

Question 20

How does chronic lung disease cause right HF?

Answer 20

Ventilation-perfusion ratio:
In alveolar hypoxia, pulmonary vessels vasoconstrict to divert blood, ensuring ventilation matches perfusion. Increasing vascular resistance in the lungs means RV hypertrophies.

Question 21

AngII has direct harmful effects in HF due to its action on which receptor?

Answer 21

AT1 receptor

Question 22

How can HF result in hyponatraemia?

Answer 22

HF increases ADH release via RAAS, excess H20 absorption leads to hyponatraemia.