Investigations and Management of Heart Failure

Question 1

What are the two key questions to ask if a patent has suspected heart failure?

Answer 1

1. Does the patient have heart failure?
   
   • What has the history /clinical examination told you?
   • Differential diagnosis?
2. Why does the patient have heart failure?
   
   • Ischaemia vs non-ischaemia

Question 2

What are the functional classifications of heart failure?

Answer 2

• Class I
  
  • No symptomatic limitation of physical activity
• Class II
  
  • Slight limitation of physical activity
  • Ordinary physical activity results in symptoms
  • No symptoms at rest
• Class III
  
  • Marked limitations of physical activity
  • Less than ordinary physical activity results in symptoms
  • No symptoms at rest
• Class IV
  
  • Inability to carry out physical activity without symptoms
  • May have symptoms at rest
  • Discomfort increases with any degree of physical activity

Question 3

What investigations would you do on a patient with suspected heart failure?

Answer 3

• Full Blood Count - anaemia not an umcommon presentation.
• Electrolyte and renal function - kidney failure can lead to symtoms and signs of heart failure.
• Glucose / hbA1C - Cardiovascular risk
• Lipid profile

Also do a BNP (brain natriuretic peptide) -This is a specialist blood test.

Question 4

Why is BNP useful?

Answer 4

Naturitic petides are a marker of cardiac stress - it is a common step in the diagnosis of heart failure.

A normal BNP almost excludes heart failure but a raised BNP points towards heart failure.

The higher th BNP, the more severe the heart failure.

BNP can give us a diagnosis and it can tell us the severity of the disease.

Question 5

What other tests can be condicted to help diagnose heart failure?

Answer 5

• ECG - Abnormal ECG + raised BNP = heart failure 95% of the time
• Chest X-ray - particularly if breathless, will show pulmonary oedema
• Echocardiogram - show reduced pressure ejection fraction
• These tell is if its IHD or something else (tells us why):
  
  • Thyroid function tests
  • Viral titres
  • Specialist cardiac imaging e.g. MRI
  • Coronary angiography

Question 6

How do you manage acute heart failure?

Answer 6

• Hospital!
• Oxygen
• Ferosemide - intravenous loop-diuretic
• Heparin (prevent DVT)
• Patient may also require
  
  • Additional ventilator support (CPAP)
  • Intravenous ‘nitrates’ - preload reduction +/- coronary vasodilation - if ongoing myocardial ischaemia.

Question 7

What does ferosamide do?

Answer 7

• It reduces filling or end-diastolic pressure so taht cardiac output is as much as it can be
• It has an immediate venodilatory effect - Reduce the pre-load
• Onset of diuretic action within 30 mins
• Peak action about 60-90 minutes
• Higher dose required in renal failure (as need to get accross the glomerulus to have action)
• Minitoring is key
  
  • Patient observations: PR, RR, BP. O₂ sats
  • Urine output!

Question 8

What are the key principles of managing heart failure long term?

Answer 8

• Correct the underlying cause
• Non-pharmacological measures
• Pharmacological therapy
  
  • Symptomatic improvement
  • Delay progression of heart failure (stop hypertrophy worsening)
  • Reduce mortality
• Treat complications / associated conditions / CVS risk factors
  
  • e.g. arrythmias

Question 9

What neuro-hormonal systems do most heart failure drugs target?

Answer 9

• Sympathetic nervous system
• Renin-Angiotensin-Aldosterone System

Question 11

What happens to the sympathetic nervous system during heart failure?

Answer 11

• Baroreceptor-mediated response
• Early compensatory mechanism to improve cardiac output:
  
  • Cardiac contractility
  • Arterial and venous vasoconstriction
  • Tachycardia
• However, long-term deleterious effects:
  
  • B-adrenergic receptors are down-regulated / uncoupled
  • Nor-adrenaline
    
    • Induces cardiac hypertrophy / myocyte apoptosis and necrosis via a-receptors
    • Induce up-regulation of the RAAS
• Reduction in heart rate variability (reduced parasympatheitc and increased sympathetic nervous system)

Question 12

What are the physiological effects of B-blockers in heart failure?

Answer 12

1. Reduce heart rate (cardiac beta receptor)
2. Reduce BP (…reduce cardiac output)
   
   • 1+2 = reduced myocardial oxygen demand
3. Redice mobilisation of glycogen
4. Negate unwanted effects of catecholamines - stop noradrenaline putting the heart into arrhythmia and causing sudden death.

Question 13

How do you give beta-blockers to patients in heart failure?

Answer 13

With care! As the failing myocardium is dependant on heart rate.

• Wait into the patient is stable
• Initiate at a low dose
• Titrate slowly up
• May have to alter concomitant medication (e.g. diuretics)

Question 14

What can you give to treat the RAAS system in heart failure?

Answer 14

• ACE inhibitors
• Angiotensin R blockets

They both have similar clinical effects and there is little advantage of giving both.

Question 15

How can patients modify their lifestyle to help manage heart failure?

Answer 15

• Reduce salt
• Reduce alcohol
• Increase aerobic exercise
• Decrease BP

Question 16

What is spironolactone?

Answer 16

This is an aldosterone receptor antagonist.

• In spite of ACE inhibits / ARB therapy, aldosterone concentration returns to normal.
• Aldosterone “escape”
• This blocks the affect of aldosterone and has a diuretic effect.

Question 17

What inverventions can be used to treat heart failure?

Answer 17

• Treat underlying cause
  
  • Valve surgery
  • Revascularisation
• Heart transpant (rare)
• Mechanical assist devices
• Inplantable pacemakers - Biventricular pacing
• Implatable defibrilators