Beta Blockers in Heart Failure

Question 1

What 3 compensatory mechanisms are there in heart failure?

Answer 1

1. Increased sympathetic activity
2. Activation of renin-angiotensin-aldosterone system
3. Myocardial hypertrophy

Question 2

What is decompensated heart failure?

Answer 2

When adapted mechanisms fail to maintain cardiac output

Question 3

What is the most common cause of heart failure?

Answer 3

Left ventricular systolic dysfunction (LVSD)

Question 4

In a normal heart, what is the resting cardiac output?

Answer 4

5L/min (approx)

Question 5

In a normal heart, what is the mean heart rate?

Answer 5

70bpm

Question 6

In a normal heart, what is the stroke volume?

Answer 6

70ml

Question 7

In a normal heart, what is the volume of filled ventricle?

Answer 7

130ml

Question 8

In a normal heart, what is the residual volume?

Answer 8

60ml

Question 9

In a normal heart, what is the fraction ejected of the ventricular contents?

Answer 9

50%

Question 10

In LVSD, what is the ejection fraction?

Answer 10

<45%

Question 11

In LVSD, at what ejection fraction do symptoms occur?

Answer 11

<35%

Question 12

In LVSD, at what ejection fraction is there risk of thrombus formation?

Answer 12

<10%

Question 13

In LVSD, when there is risk of thrombus formation, what drug is required?

Answer 13

Anti-coagulant

Question 14

What changes happen to the heart in systolic dysfunction?

Answer 14

Heart increases in size, chambers dilate and become more rounded

Question 15

What are the causes of systolic dysfunction?

Answer 15

Excessive elongation of the muscle fibres which causes weaker contractions

Altered shape of the ventricles reduces ability to eject blood

Question 16

What are the causes of diastolic dysfunction?

Answer 16

Hypertrophy - wall thickening - decrease in ventricular volume

Decreases ability to relax and receive blood

Question 17

What is systolic failure?

Answer 17

Ventricle unable to pump efficiently

Question 18

What is diastolic failure?

Answer 18

Ventricle unable to fill adequately -> inadequate cardiac output

Question 19

What is the result of increased and sustained sympathetic drive?

Answer 19

Left ventricular dysfunction and remodelling

Down regulation and desensitisation of cardiac beta receptors

Question 20

What does down regulation and desensitisation of cardiac beta receptors lead to?

Answer 20

Impairment of myocardial reserve and exercise tolerance

Question 21

What are the cellular abnormalities in the heart manifested by?

Answer 21

1. Defects in calcium handling of the sarcoplasmic reticulum
2. Defects in myocardial energetics
3. Ongoing loss of cardiomyocytes through necrosis or apoptosis

Question 22

Carvedilol

What receptor(s) is this selective for, and what dosage?

Answer 22

Beta-1 antagonist, Alpha-1 antagonist

Twice daily

Question 23

Metoprolol

What receptor(s) is this selective for, and what dosage?

Answer 23

Beta-1 selective antagonist

Once daily

Question 24

Bisoprolol

What receptor(s) is this selective for, and what dosage?

Answer 24

Beta-1 selective antagonist

Once daily

Question 25

Nevibolol

What receptor(s) is this selective for, and which patients is this approved for?

Answer 25

Beta-1 selective antagonist

Patients over 70