Session 11 - Heart failure Flashcards

1
Q

Define heart failure

A

‘a state in which the heart fails to maintain an adequate circulation for the metabolic needs of the body despite an adequate filling pressure’.

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2
Q

Give five causes of chronic right heart failure

A
  • Pulmonary hypertension
  • Arrythmias
  • Chronic lung disease
  • Left to right shunt
  • Left heart failure
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3
Q

Give six causes of chronic left heart failure?

A
  • Systemic hypertension
  • Arrythmias
  • Coarctation of the aorta
  • Anaemia
  • Thyrotoxicosis
  • Ischaemic heart disease
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4
Q

Give two causes of acute right heart failure

A
  • Pulmonary embolism

- Rupture of tricuspid valve cusp

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5
Q

Give two causes of acute left heart failure

A
  • Myocardial infarction

- Rupture of mitral or aortic valve

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6
Q

Give three causes of congestive heart failure

A
  • Thyrotoxicosis
  • Lesions of the aortic and mitral valves
  • Anaemia
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7
Q

Give six compensatory mechanisms for heart failure

A
  • Activation of sympathetic nervous system
  • Activation of the renin-angiotensin-aldosterone system
  • Anti-diuretic hormones
  • Nitric oxide
  • Prostaglanding E2 and I2
  • Hypertrophy of cardiac muscle
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8
Q

How is sympathetic nervous system activated in heart failure?

A

Fall in blood pressure and blood volume detected by baroreceptors in the aortic arch and carotid sinus

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9
Q

How does activation of sympathetic nervous system compensate for heart failure?

A
  • Increased heart rate and contractility to increase cardiac output - increases the work load of the heart
  • Vasoconstriction of arterioles - increases blood pressure but also increases the afterload
  • Renin secretion by the kidneys
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10
Q

How does activation of renin-angotensin-aldosterone system occur?

A
  • Reduced renal blood flow
  • SNS induction of renin secretion
  • Secretion of endothelin by vascular endothelial cells, causes renal vasoconstriction > renin-angotensin-aldosterone system activated
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11
Q

Give the sequence of events which leads to RAAS activation

A

Angiotensin –> (renin) –> Angiotensin 1 –> (Angiotensin Converting Enzyme) –> Angiotensin 2

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12
Q

What does angiotensin 2 do?

A

Activated by RAAS sequence
Promotes vasoconstriction and release of aldosterone from adrenal cortex
Causes increased blood pressure and salt and water retention by kidneys, increasing blood volume and increasing venous return and stroke volume

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13
Q

How do anti-diuretic hormones compensate for heart failure?

A
  • HF increases ADH secretion resulting in water retention and increased blood volume
  • Reduced urine output by kidneys contributes to weight gain and oedema fluid
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14
Q

What happens to nitric oxide to compensate for HF?

A

A powerful vasodilators which is inhibited in heart failure

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15
Q

How do prostaglands E2 and I2 compensate for HF?

A

Act as vasodilators on afferent renal arterioles to attenuate effects of Na+/RAAS

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16
Q

What effect does hypertrophy of heart muscle have in compensation for heart failure?

A
  • Response to increased demand
  • Decreases ventricular volume which exacerbates reduced cardiac output
  • The heart may remodel and dilate
  • Increasing venous pressure may push heart to the right of starling’s curve resulting in damage to myocardium Results in reduced stroke volume for a given venous pressure..
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17
Q

Give five main symptoms of left heart failure

A
Fatigue
Exertional dyspnoea
Pulmonary oedema
Displaced apex beat and cardiomegaly
Tachcardia
18
Q

Why do you get fatigue in left heart failure?

A

Cardiac output does not meet metabolic needs, meaning some tissues insufficiently perfused - acidocis may ensue
- Pulmonary oedema impars gas exchange causing a state of hypoxia

19
Q

Why do you get exertional dyspnoea in left heart failure?

A

Heart is unable to meet the increasing metabolic demand of tissues during exercise, acidosis may occur

20
Q

Why do you get pulmonary oedema in left heart failure?

A

Increased venous pressure results in increased hydrostatic pressure in the mpulmonary capillaries. Fluid moves into the interstitium resulting in oedema.

21
Q

What are pulmonary crackles?

A

Fluid collects in base of the lungs > pulmonary crackles

22
Q

What is orthopnoea?

A

Whilst lying down fluid distributes across base of lungs, causing breathlessness due to impaired gas exchange

23
Q

What is the result of breathlessness?

A

Impairment of gas exchange

24
Q

What is cyanosis?

A

Result of imparied gas exchange leading to hypoxaemia

25
Q

Why do you get displaced apex beat and cardiomegaly in left ventricular heart failure?

A

Left ventricular hypertrophy

26
Q

Why tachcyardia in LVHF?

A

Sympathetic response to falling CO

27
Q

What are five signs and symptoms of right heart failure?

A
Fatigue
Breathlessness
Raised JVP
Peripheral oedema 'pitting oedema'
Hepatomegaly
28
Q

Why does fatigue occur in RVHF

A

Decreased flow to the lungs results in hypoxaemia due to a ventilation/perfusion mismatch. Insufficient oxygen for metabolic needs.

29
Q

What happens in breathlessness in in RVHF?

A

Decreased oxygenated blood enters systemic circulation. Hyperventilation results in order to increase the partial pressure of oxygen.

30
Q

Why do you get raised JVP in RVHF?

A

Failure of right side of the heart to pump causes a rise in venous pressure and distension of the jugular veins.

31
Q

What is peripheral oedema in RVHF?

A

Increased venous pressure also raises capillary pressure. Increased hydrostatic pressure causes fluid to move into the interstitium.
Oedema causes weight gain

32
Q

What is hepatomegaly in RHVF?

A

Back up of blood in the inferior vena cava causes congestion of the hepatic veins leading to hepatic engorgment.

33
Q

Name four targets of drugs for manipulation of cardiac output?

A

Kidneys - Regulate blood volume
Arterioles- regulate bp
Myocardium - regulates force of contraction - the force is developed in a muscle fibre,
SAN - regulates heart rate

34
Q

Give three life style changes which can be used to tackle heart failure?

A

Reduce salt
Reduce alcohol consumption
Increase aerobic exercise

35
Q

Give three anti-hypertensives that can be used to treat HF

A

a1 antagonists
Diuretics e.g. loop diurteics, spironolactone
ACE-inhibitors

36
Q

Give a drug which causes reduction of cardiac workload

A

B-blocker

37
Q

Give a positive inotropic drug

A

Digoxin - increases intracellular calcium

38
Q

Give three anti-arrhymic drugs which can be used to treat HF

A

Sodiumchannel blockers
B blocker
Calcium channel blocker

39
Q

Give four types of drugs which can be given for HF

A

Anti-hypertensives
Reduction of cardiac workload
Positive inotropes
Anti arrhythmic drugs

40
Q

What does alpha-TNF do?

A

Decreases myocardial function