Acute Left Ventricular Failure

Question 1

What is acute left ventricular failure?

Answer 1

occurs when an acute event results in the left ventricle being unable to move blood efficiently through the left side of the heart and into the systemic circulation.

Question 2

What is cardiac output?

Answer 2

volume of blood ejected by the heart per minute.

Question 3

What is stroke volume?

Answer 3

volume of blood ejected during each beat.

Question 4

What is the equation for stroke volume?

Answer 4

CO = SV x HR

Question 5

What is the main clinical sign in acute LV failure?

Answer 5

Pulmonary oedema

Question 6

What are the main triggers of acute LV failure? (5)

Answer 6

• Iatrogenic (e.g., aggressive IV fluids in a frail elderly patient with impaired left ventricular function)
• Myocardial infarction
• Arrhythmias
• Sepsis
• Hypertensive emergency (acute, severe increase in blood pressure)

Question 7

What are the symptoms of acute LV failure? (3)

Answer 7

• Shortness of breath (exacerbated lying flat)
• Looking and feeling unwell
Cough with frothy white or pink sputum

Question 8

What type of respiratory failure does acute LV failure cause?

Answer 8

type 1 respiratory failure (low oxygen without an increased carbon dioxide)

Question 9

What signs on examination are seen in acute LV failure? (6)

Answer 9

• Raised respiratory rate
• Reduced oxygen saturations
• Tachycardia (fast heart rate)
• 3rd heart sound (GALLOP RHYTHM S3)
• Bilateral basal crackles (sounding “wet”) on auscultation of the lungs
• Hypotension in severe cases (cardiogenic shock)

Question 10

What investigations are done in acute LV failure? (5)

Answer 10

• ECG to look for ischaemia and arrhythmias
• Bloods for anaemia, infection, kidney function, BNP, and consider troponin if suspecting myocardial infarction
• Arterial blood gas (ABG)
• Chest x-ray
• Echocardiogram

Question 11

Where is BNP released from?
When does this occur?

Answer 11

Heart ventricles
When cardiac muscle is stretched beyond normal range

Question 12

What does a raised BNP suggest?

Answer 12

Heart is overloaded and can’t pump effectively

Question 13

What is the normal action of BNP? (2)

Answer 13

relax the smooth muscle in blood vessels. This reduces systemic vascular resistance, making it easier for the heart to pump blood through the system.

acts on the kidneys as a diuretic to promote water excretion in the urine.
• This reduces the circulating volume, helping to improve the function of the heart in someone that is fluid-overloaded.

Question 14

What are some other causes of raised BNP aside from heart failure? (5)

Answer 14

• Tachycardia
• Sepsis
• Pulmonary embolism
• Renal impairment
• COPD

Question 15

What is a normal ejection fraction?

Answer 15

Over 50%

Question 16

What CXR findings are seen in acute LV failure? (3)

Answer 16

Cardiomegaly

Upper lobe venous diversion

Signs of fluid overload

Question 17

What is upper lobe venous diversion?

Answer 17

• Usually, when standing erect, the lower lobe veins contain more blood, and the upper lobe veins remain relatively small.
• In acute LVF, there is such a back-pressure that the upper lobe veins also fill with blood and become engorged.
• This is referred to as upper lobe diversion. This is visible as increased prominence and diameter of the upper lobe vessels on a chest x-ray.

Question 18

What signs of fluid overload can be seen on a cxr?

Answer 18

• Bilateral pleural effusions
• Fluid in interlobar fissures (between the lung lobes)
• Fluid in the septal lines (Kerley lines)

Question 19

What is the basic management of acute LV failure?

Answer 19

Sodium

• S – Sit up
• O – Oxygen
• D – Diuretics
• I – Intravenous fluids should be stopped
• U – Underlying causes need to be identified and treated (e.g., myocardial infarction)
• M – Monitor fluid balance

Question 20

What specialist treatment can be given in acute LV failure? (6)

Answer 20

• Intravenous opiates, such as morphine, which act as vasodilators
• Intravenous nitrates act as vasodilators, and may be considered in severe hypertension or acute coronary syndrome
• Inotropes, such as dobutamine, to improve cardiac output
• Vasopressors, such as noradrenalin, to improve blood pressure
• Non‑invasive ventilation
• Invasive ventilation (involving intubation and sedation)

Question 21

What is the action of morphine when given in acute LV failure?

Answer 21

Vasodilator

Question 22

What is the action of initropes?

Answer 22

Improve cardiac output by increasing contractility of the heart

Question 23

What is the action of vasopressors in acute LV failure?

Answer 23

Vasoconstriction to increase BP