Systems Pathology: Heart failure Flashcards

1
Q

Two main problems/failures in heart failure:

A
  • Fluid congestion (backward failure)
  • Inadequate blood flow to tissues (forward failure)
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2
Q

What happens in actute heart failure?

A

In acute failure events take place rapidly and consequence is forward (shock)

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3
Q

What happens in chronic heart failure?

A

In chronic failure compensatory mechanisms may be brought into play and backward failure dominates (congestion)

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4
Q

3 Compensatory Mechanisms in Heart Failure

A
  • Ventricular chamber enlargment: increases amount of blood in ventricle, so ejeccts more, but at cost of fluid retention
  • Muscle mass increases: can eject more, but requires more oxygen to larger muscle
  • Sympathetic stimulation: increases heart rate, contractility, redistribution and retention of fluid
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5
Q

Ways of stimulation renin release from kidney

A
  • Sympathetic stimulation(b-adrenoceptors)
  • Renal artery hypotension
  • Decreased somdium delivery to distal tubules
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6
Q

Functions of angiotensin II

A
  • Constricts resistance vessels, thereby increasing systemic vascular resistance and arterial pressure
  • Causes aldosterone release from adrenal cortex; acts on kidney to increase sodium and fluidd retention
  • Stimulates ADH release, increases fluid retention
  • Stimulates thirst
  • NA release from sympathetic nerve endings, and inhibits its reuptake; Enhances sympathetic adrenergic function
  • Stimulates hypertrophy of cardiac muscle and arterial smooth muscle
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7
Q
A
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8
Q

What happens in cardiac remodelling and what brings it on?

A
  • Hypertrophy in response to increased demands
  • Adrenergic stimuli, cytokines (TNFa), and Angiotensin II mediate effects
  • Beneficial in increasing cardiac output but these stimulants also have adverse effects
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9
Q

Benefits and harm brought about by adrenergic stimuli in cardiac remodelling

A

+ve: Contractility, Hypertrophy

-ve: Myocyte apoptosis, Myocyte toxicity

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10
Q

Benefits and harm brought about by angiotensin II in cardiac remodelling

A

+ve: hypertrophy

-ve: Changes expression of contractile proteins

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11
Q

Benefits and harm brought about by Ctyokines(TNFa) in cardiac remodelling

A

+ve: hypertrophy

-ve: Remodelling of matrix, dilation

A dilating chamber is a failing chamber

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12
Q

Signs of LVF

A
  • Raised end diastolic BP
  • Raised left atrial pressure
  • Raised pulmonary capillary pressure
  • Increased diffusion barrier for gas exchange
  • Increased pulmonary oedema
  • Breatlessness
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13
Q

Causes of LVF

A
  • Acute ventricular dysrhytmias (VF)
  • Myocardial infarction and ichaemic heart disease
  • Longstanding hypertension
  • Valve disease (aortic and mitral)
  • cardiomyopathies and drugs
  • congenital heart disease

Insufficient pump power- problem with heart muscle

Obstruction of outward flow- valve, aorta, arteries, arterioles

Obstruction of inflow- pericardial effusion, constrictive pericarditis

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14
Q

Signs and symptosm of RVF

A
  • Raised end diastolic pressure
  • Raised right atrial and JVP
  • Raised central venous pressure
  • Liver distension (abdominal discomfort)
  • Increased interstitial fluid formation (peripheral oedema)
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15
Q

Causes of RVF

A
  • Most common cause is LVF
  • Acute right ventricular failure - massive pulmonary thromboembolism
  • Chronic right ventricular failure due to chronic lung disease and pulmonary hypertension (cor pulmonale)
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16
Q

How can pulmonary emphyseme cause cor pulmonale

A
  • Emphysema destroys alveolar walls
  • Loss of lung capilarues
  • Failure of lung ventilation
  • Hypoxia CONSTRICTS pulmonary arteries
  • Pulmonary hypertension
17
Q

Congetive cardiac failure

A
  • CCF is a combination of both RVF and LVF
  • Commonest cause of CCF is ischaemic heart disease followed by other cause sof LVF
  • Cardiomyopathies and drugs may also cause it
18
Q

Causes of high output cardiac failure

A

Heart muscle essentially normal but output cannot adequately perfuse tissue​

  • Arteriovenous fistula-blood bypass tissue
  • Septic shock-vasodilation
  • Anaemia -oxygen requirements not mett
  • Thyrotoxicosis-increased tissue ddemand
19
Q
A