5. LV Dysfunction and Heart Failure (1)

Question 1

What is NICE’s definition of heart failure?

Answer 1

HF is a complex clinical syndrome of symptoms that suggest the efficiency of the heart as a pump is impaired

Question 2

What is ESC’s definition of heart failure?

Answer 2

HF can be defined as an abnormality of cardiac structure or function leading to failure of the heart to deliver oxygen at a rate commensurate to the requirements of metabolising tissues, despite normal filling pressures (or at expense of increased filling pressures)

Question 3

What are the 2 distinctions of heart failure?

Answer 3

• Heart failure due to left ventricular systolic dysfunction (LVSD)
• Heart failure with preserved ejection fraction (HFPEF)

Question 4

What are 2 causes of heart failure?

Answer 4

• Structural abnormalities of heart (aortic stenosis/mitral regurgitation)
• Functional abnormalities

Question 5

What is the most common cause of heart failure?

Answer 5

Coronary artery disease - blockage leads to cardiac muscle death and scarring and heart becomes dysfunctional

Question 6

What type of therapy gives the most benefit in heart failure?

Answer 6

Vasodilator therapy via neurohumoral blockade (SNS and RAAS) to treat peripheral effects

Question 7

Are LV dysfunction and heart failure the same thing?

Answer 7

No LV dysfunction can lead to heart failure but not always

Question 8

What is the result of reduced cardiac output (forward flow) in heart failure?

Answer 8

• Causes impairment of flow to lungs and skeletal muscle

- Results in fatigue and exercise intolerance

Question 9

What is the result of increased filling pressures (backward flow) in heart failure?

Answer 9

• Increased LV pressure = back pressure goes to left atrium and then to pulmonary venous circulation to cause pulmonary oedema (hence why patients sit upright and use all accessory respiratory muscles to increase air intake)
• Increased RV pressure = back pressure goes to right atrium and then to peripheral venous circulation to cause peripheral oedema, ascites, pleural effusion and increased jugular venous pressures

Question 10

How does heart failure affect the Frank-Starling mechanism?

What does this mean?

Answer 10

• It shifts the curve downwards and to the right

- A large chance in LV EDP is required for a small change in SV/CO

Question 11

What happens if cardiac output decreases below a certain level?

Answer 11

Get symptoms of low CO:

• Fatigue
• Failure to maintain blood pressure

Question 12

What happens if LV EDP increases beyond a certain level?

Answer 12

Get symptoms of high LV EDP:

• Pulmonary oedema (breathlessness)
• Peripheral oedema

Question 13

What can be given to a patient with heart failure and increased LV EDP?
Does this affect cardiac output?

Answer 13

• Patient can be given a diuretic and vasodilator to decrease LV EDP
• Without sacrificing CO level

Question 14

How do diuretics work?

Answer 14

Cause sodium and water loss in urine to decrease preload and therefore decrease LV EDP

Question 15

What is the evidence for the effectiveness of Spironolactone in heart failure patients?

Answer 15

• At 12 months patients receiving Spironolactone have an increased survival probability (80%) compared to patients receiving a placebo (75%)
• As time progresses, the difference between the 2 groups increases

Question 16

What is the evidence that some vasodilator treatments are effective in heart failure patients?

Answer 16

• Patients received either placebo, Prazosin (alpha blocker = vasodilator) or Hydralazine-Isosorbide Dinitrate combination
• No difference between placebo and Prazosin mortality rates
• Significant decrease in mortality rates in Hyd-Iso combination group (also showed increased LV ejection fraction)