S9) Heart Failure

Question 1

What is heart failure?

Answer 1

Heart failure is a state in which the heart fails to maintain an adequate circulation for the needs of the body despite an adequate filling pressure

Question 2

Outline the aetiology of heart failure

Answer 2

• Ischaemic Heart Disease
• Hypertension
• Dilated/hypertrophic Cardiomyopathy
• Valvular/Congenital Heart Disease
• Pericardial disease
• Arrhythmias

Question 3

What are the clinical signs of chronic heart failure?

Answer 3

• Pulmonary congestion
• Venous congestion
• Dependent oedema

Question 4

What are the symptoms of chronic heart disease?

Answer 4

• Dyspnoea
• Lethargy
• Orthopnoea

Question 5

Describe the clinical features of Class I heart failure

Answer 5

No symptomatic limitation of physical activity

Question 6

Describe the clinical features of Class II heart failure

Answer 6

• Slight limitation of physical activity
• Ordinary physical activity results in symptoms
• No symptoms at rest

Question 7

Describe the clinical features of Class III heart failure

Answer 7

• Marked limitation of physical activity
• Less than ordinary physical activity results in symptoms
• No symptoms at rest

Question 8

Describe the clinical features of Class IV heart failure

Answer 8

• Inability to carry out any physical activity without symptoms
• May have symptoms at rest
• Discomfort increases with any degree of physical activity

Question 9

What are the factors affecting cardiac output?

Answer 9

• Heart rate
• Venous capacity (preload)
• Myocardial contractility
• Arterial and peripheral impedance (afterload)

Question 10

What is Starling’s Law of the Heart?

Answer 10

“The force developed in a muscle fibre depends on the degree to which the fibre is stretched.”

Question 11

Describe the pathophysiology of Left Ventricular Systolic Dysfunction

Answer 11

• Increased LV capacity
• Reduced LV cardiac output
• Thinning of the myocardial wall

I. Fibrosis and necrosis of myocardium

II. Activity of matrix proteinases

Question 12

What are the causes of Left Ventricular Systolic Dysfunction?

Answer 12

• Mitral valve incompetence
• Neuro-hormonal activation
• Cardiac Arrhythmias

Question 13

Which structural heart changes occur after Left Ventricular Systolic Dysfunction?

Answer 13

• Loss of muscle
• Uncoordinated myocardial contraction
• Changes to the ECM (increase in collagen)
• Change of cellular structure and function (myocyte hypertrophy)

Question 14

Describe ventricular remodeling after acute infarction

Answer 14

Question 15

Describe ventricular remodeling in diastolic and systolic heart failure

Answer 15

Question 16

Label the following images:

Answer 16

Question 17

Identify the 5 different pathways for neuro-hormonal activation

Answer 17

• Sympathetic Nervous System
• Renin-Angiotensin-Aldosterone System
• Natriuretic Hormones
• Anti-Diuretic Hormone
• Endothelin

Question 18

Why is SNS stimulated in heart failure?

Answer 18

Early compensatory mechanism to improve cardiac output:

• Cardiac contractility
• Arterial and venous vasoconstriction
• Tachycardia

Question 19

Outline the long-term deleterious effects of the SNS in heart failure

Answer 19

Question 20

When is RAAS commonly activated in heart failure?

Answer 20

• Reduced renal blood flow
• SNS induction of renin from macula densa

Question 21

Outline the action of RAAS in heart failure

Answer 21

Question 22

In terms of the brain, blood vessels, heart and kidney, explain how Angiotensin II plays a key role in organ damage

Answer 22

Question 23

When are natriuretic peptides released in heart failure?

Answer 23

• Atrial distension
• Increased blood volume and pressure

Question 24

Outline the action of natriuretic peptides in heart failure

Answer 24

Question 25

Outline the effect of ADH (vasopressin) in heart failure

Answer 25

ADH is increased in heart failure: - Increased H₂O retention - Tachycardia and increased TPR → increased CO

Question 26

Outline the action of endothelin in heart failure

Answer 26

- **Endothelin** is secreted by vascular endothelial cells resulting in renal vasoconstriction via autocrine activity - Activates RAAS (increased levels in some patients with heart failure)

Question 27

Outline the effect of other chemicals in heart failure: - Prostaglandin E₂ and I₂ - Nitric oxide - Bradykinin

Answer 27

- **Prostaglandins**: vasodilators stimulated by NA and RAAS to counter their effects - **Nitric oxide:** potent vasodilator produced by endothelial cells via NO synthase (NO synthase may be blunted in HF) - **Bradykinin**: promotes natriuresis, vasodilatation and stimulates production of PGs

Question 28

What is oedema?

Answer 28

- **Oedema** is the excessive volume of fluid within the tissues (interstitial / intracellular) which can occur due to changes in capillary dynamics - It is often seen in heart failure as there is increased capillary hydrostatic pressure

Question 29

Vascular endothelium increases in peripheral arterial resistance. Why is this?

Answer 29

- SNS - RAAS - Reduced NO - Increased endothelin

Question 30

Changes in vascular endothelium leads to skeletal muscle changes. Identify some

Answer 30

- Reduced skeletal muscle **blood flow** - Reduction in skeletal **muscle mass** (cachexia) - Abnormalities of **structure** and **function**

Question 31

Describe the renal effects associated with changes in the vascular endothelium

Answer 31

- **GFR is maintained in early HF** by haemodynamic changes at the glomerulus – increased Na⁺ /H₂O retention due to neurohormonal activation - **GFR falls in severe HF** due to reduced renal blood flow leading to a subsequent rise in serum urea and creatinine

Question 32

Describe the multi-factorial aetiology of anaemia associated with vascular endothelium changes

Answer 32

- Chronic inflammatory disease - Expanded plasma volume - Drug therapy (ACEi / Aspirin) - Iron malabsorption - Chronic renal failure

Question 33

Heart Failure with Preserved Ejection Fraction (HFpEF) occurs in almost 50% of heart failure patients. Describe the clinical features of this condition

Answer 33

- Frequently elderly and female - Often history of hypertension / diabetes / obesity - Normal LV function with concentric remodelling

Question 34

In four steps, describe the pathophysiology of HFpEF

Answer 34

⇒ **Reduced LV compliance** and impaired myocardial relaxation ⇒ **Impaired diastolic LV filling** (dependent on high LA pressure) ⇒ **RV dysfunction** results from **high LA and PA pressure** ⇒ Triggers **neuro-hormonal activatio**n as per systolic heart failure

Question 35

Identify the 5 clinical syndromes of heart failure

Answer 35

- Left Sided Heart Failure - Right Sided Heart Failure - Congestive cardiac failure - LVSD (pump failure) - HFpEF (failure of LV relaxation)

Question 36

Identify the symptoms of Left Sided Heart Failure

Answer 36

- Fatigue - Exertional dyspnoea - Orthopnoea - Paroxysmal nocturnal dyspnoea (PND)

Question 37

What are the clinical signs of Left Sided Heart Failure?

Answer 37

- Tachycardia - Cardiomegaly (displaced apex beat) - 3rd or 4th heart sound (‘Gallop rhythm’) - Functional murmur of mitral regurgitation - Basal pulmonary crackles (fluid in the lungs) - Peripheral oedema

Question 38

Describe the aetiology of Right Sided Heart Failure

Answer 38

- Chronic lung disease - Pulmonary embolism / pulmonary hypertension - Pulmonary/tricuspid valvular disease - Left-to-right shunts (ASD/VSD) - Secondary to left heart failure (most frequent)

Question 39

What are the signs and symptoms of Right Heart Failure?

Answer 39

- Fatigue - ↑ JVP - Pitting oedema - Ascites - Pleural effusion - Dyspnoea

Question 40

What is congestive (biventricular) heart failure?

Answer 40

- **Congestive heart failure** is a chronic progressive condition in which the heart's function as a pump is inadequate to meet the body's needs - Both the right and left sides of the heart fail to pump adequately, hence, the signs and symptoms of both right and left heart failure develop