Acute left ventricular failure (Acute LVF)

Question 1

1) When does LVF occur?
2) What is pulmonary oedema?
3) How does acute LVF then cause pulmonary oedema?

Answer 1

1) When the LV is unable to adequately move blood through the left side of the heart causing a backlog of blood in the left atrium, pulmonary veins and lungs
2) Condition where the lung tissues and alveoli become full of interstitial fluid - interfering with gas exchange
3) The increased volume of blood in the lungs due to acute LVF increases the pressure inside, which causes more fluid to leak out from the vessels and less fluid to be reabsorbed, This increases the amount of fluid in the surrounding tissues causing pulmonary oedema

Question 2

Name 2 causes or triggers of acute LVF

Answer 2

• Iatrogenic i.e. aggressive IV fluids in patients with already impaired LV function
• Sepsis
• MI
• Arrhythmias

Question 3

1) How does acute LVF typically present?
2) What exacerbates the typical presentation of acute LVF?
3) What type of respiratory failure does acute LVF cause and what does this mean?

Answer 3

1) Rapid onset breathlessness
2) Lying down
3) Type 1 - low oxygen without an increase in CO2 in the blood

Question 4

Name 2 features that may be seen on examination of a patient in acute LVF

Answer 4

• Increased respiratory rate
• Decreased oxygen saturations
• Tachycardia
• 3rd heart sound
• Bilateral basal crackles on auscultation
• Raised JVP and peripheral oedema if there’s also right HF

Question 5

1) Which hormone is released when the ventricles are stretched?
2) How does this hormone work?
3) What does a high BNP result indicate?
4) Comment on the sensitivity and specificity of a BNP test
5) A positive BNP result can have other causes as well as HF - name 2 of these

Answer 5

1) B-type natriuretic peptide
2) It relaxes SM in blood vessels to reduce resistance and decrease BP and it acts as a diuretic in the kidney
3) The heart is overloaded with blood
4) It’s sensitive but not specific
5) tachycardia, sepsis, pulmonary embolism, COPD and a renal impairment

Question 6

1) In the context of acute LVF, what is an echocardiography useful to assess?
2) What is the main measurement an echocardiography is used for, and what does it mean?

Answer 6

1) LV function and any structural abnormalities of the heart
2) Ejection fraction - percentage of blood in the LV that’s squeezed out of every contraction

Question 7

1) What is the management of acute LVF? (5)
2) How is severe acute pulmonary oedema/cardiogenic shock managed?

Answer 7

1) Stop IV fluids, sit patient upright, oxygen, loop diuretics i.e. IV furosemide, monitor fluid balance
2) Non-invasive ventilation i.e. CPAP (intubation and ventilation if NIV doesn’t work) and occasionally IV opiates for vasodilation and inotropes i.e. noradrenaline infusion to strengthen heart contractions. However by this point the patient would need to be in an ICU