CVS: Heart Failure

Question 1

Define heart failure.

Answer 1

A state in which the heart fails to maintain an adequate circulation for the needs of the body despite an adequate filling pressure.

Question 2

Describe some causes of heart failure.

Answer 2

• IHD is the primary cause of systolic HF
• Hypertension
• Dilated cardiomyopathy (e.g. In pregnancy)
• Valvular heart disease
• Pericardial disease
• Arrhythmias

Question 3

Explain potential pathophysiology of heart failure.

Answer 3

1. Heart rate (rises when CO is too low)
2. Venous capacity (LV preload)
3. Aortic and peripheral impedance (afterload)
4. Myocardial Contractility (muscle may weaken)

Question 4

Describe the drawing of a normal relationship between central venous pressure (end diastolic pressure) and CO.

Answer 4

The greater the central venous pressure (end diastolic pressure) the greater the cardiac output.

Question 5

Describe how the relationship between central venous pressure (end diastolic pressure) and CO alters with increasing severity of heart failure.

Answer 5

Up to a point, increasing central venous pressure (end diastolic pressure) causes an increase in CO. However this peaks until eventually an increase in central venous pressure (end diastolic pressure) will result in a decrease in CO.

NOTE: This is important when managing patients with HF

Question 6

Desire the effect sympathetic activation has on HF.

Answer 6

Basically the activation of the sympathetic system due to HF makes the HF even worse. It does this by…

• Activates RAAS which leads to fluid retention , leading to increased wall stress and subsequent hypertrophy
• Activates vasoconstriction which leads to increased wall stress and increased myocardial oxygen demand. All of this leads to decreased contractility
• Leads to increased heart rate and myocyte damage

Question 7

Describe the involvement of the RAAS system in HF.

Answer 7

As there is reduced renal blood flow, the RAAS system is commonly activated in HF.

This leads to elevated angiotensin II production which promotes salt and water retention through aldosterone release and it promotes vasoconstriction.

Question 8

Give an equation for NET filtration pressure.

Answer 8

Hydrostatic pressure- Osmotic pressure

Question 9

Why does oedema develop during heart failure?

Answer 9

Increased capillary hydrostatic pressure means more fluid moves out into the interstitum.

Question 10

Name some drugs that can be given to patients during HF.

Answer 10

• Beta blockers (reduce the hearts demand for oxygen)
• Diuretics to increase water loss from kidneys
• Digoxin to slow ventricle rate
• Bloof thinners such as heparin or warfarin

Question 11

What is left ventricular systolic dysfunction?

Answer 11

When there is increased LV capacity and reduced LV cardiac output.

Question 12

What is heart failure with preserved ejection fraction? (HFpEF)

Answer 12

Reduced LV filling as the ventricles don’t fully relax and becomes dependant on high LA pressure.

Question 13

Give some clinical features of left sided heart failure.

Answer 13

• Tachycardia
• Cardiomegaly (displayed apex beat)
• Murmur due to mitral valve regurgitation
• Pulmonary crackles
• Peripheral oedema

Question 14

Give some clinical features of right sided heart failure.

Answer 14

• Raised JVP
• Hepatic enlargement
• Pleural effusion