Systems Pathology: Heart Failure

Question 1

Heart failure

Answer 1

Condition caused by impairment of heart’s function as pump

Question 2

Clinical manifestations of heart failure

Answer 2

Fluid congestion (backward failure)
Inadequate blood flow to tissues (forward failure)

Question 3

Compare acute and chronic heart failure

Answer 3

In acute failure, events are rapid and consequence is forward failure (shock)

In chronic, compensatory mechanisms are brought into play and backward failure dominates (congestion)

Question 4

Compensatory mechanisms in chronic heart failure

Answer 4

Ventricular chamber enlargement - increases amount of blood in ventricle, so more is ejected at cost of fluid retetion

Muscle mass increase - Can eject more but more O2 required for larger muscle

Sympathetic stimulation - Increase in heart rate and contractility, redistribution and retention of fluid

Question 5

Cardiac remodelling that occurs in heart failure

Answer 5

Hypertrophy in response to greater demand

Adrenergic stimuli, cytokines & angiotensin II mediate effects

These increase cardiac output at cost of adverse effects

Question 6

Benefit/Harm from adrenergic signals to remodel heart after failure

Answer 6

Benefit

• Contractility
• Hypertrophy

Harm

• Myocyte apoptosis
• Myocyte toxicity

Question 7

Benefit/Harm from angiotensin II to remodel heart after failure

Answer 7

Benefit
- Hypertrophy

Harm
- Changed expression of contractile proteins

Question 8

Benefit/Harm from Cytokines (TNFa) to remodel heart after failure

Answer 8

Benefit
- Hypertrophy

Harm

• Remodelling of matrix
• Dilatation

Question 9

What does a dilating chamber indicate

Answer 9

A dilating chamber is a failing chamber

Question 10

Main 3 Types of heart failure

Answer 10

Left Ventricular Failure
Right Ventricular Failure
Congestive cardiac failure

Question 11

Consequences of LV failure

Answer 11

Raised end diastolic pressure –> raised LA pressure –> Raised pulmonary capillary pressure –>

Increased diffusion barrier for gas exchange & pulmonary oedema leading to breathlessness

Question 12

NY heart association - classification of heart failure

Answer 12

Class I No limitation of physical activity
Class II Slight limitation of activity (breathlessness/fatigue with moderate exercise)
Class III Marked limitation of activity (breathlessness with minimal exercise)
Class IV Severe limitation of activity (symptoms at rest)

Question 13

LVF on CXR

Answer 13

Alveolar oedema
kerly B Lines
Cardiomegaly
Dilated Upper lobe vessels
pleural Effusion

(ABCDE)

Question 14

Causes of LVF

Answer 14

Acute ventricular dysrythmias (VF)
MI/Ischaemic heart disease
Longstanding hypertension
Valve disease (Left side)
Cardiomyopathies & Drugs
Congenital heart disease

Question 15

Consequences of RV Failure

Answer 15

Raised end diastolic pressure –> raised RA & jugular venous pressures –> Raised central venous pressures –>

Hepatomegaly (abdominal discomfort) & pulmonary oedema

Question 16

Causes of RVF

Answer 16

Left Heart Disease
Lung disease
Thromboemboli
Haematopathologies
Pulmonary Arterial Hypertension (rare)

Question 17

RVF due to LV disease

Answer 17

Coronary artery disease causes myocyte damage; LV dilates & fails, increasing backward pressure in RA and pulmonary capillary bed
Pressure increases in pulmonary arteries to compensate leading to further damage to pulmonary arterial wall and greater resistance

Question 18

Emphysema causing RVF

Answer 18

Destruction of alveolar walls and loss of lung capillaries; failure of lung ventilation so hypoxia constricts pulmonary arteries and causes pulmonary hypertension and RVF

Question 19

Cor pulmonale

Answer 19

RVF as result of respiratory disease

Question 20

Congestive heart failure and causes

Answer 20

Combination of both LVF & RVF

Commonest cause of CCF is ischaemic heart disease followed by other causes of LVF
Also cardiomyopathies/drugs

Question 21

High Output Cardiac Failure

Answer 21

Heart muscle essentially normal but output cannot adequately perfuse tissue

Question 22

Consequences of High Output Cardiac Failure

Answer 22

Arteriovenous fistula - blood bypasses tissue
Septic shock
Anaemia
Thyrotoxicosis