Heart Failure Pharmacology

Question 1

What are the principles of treating heart failure? (4)

Answer 1

Reduce Preload
Reduce Afterload
Increase Contractility
Restrict Cardiac Work

Question 2

How does reducing preload help treat cardiac failure?

Answer 2

Increase stroke volume
by improving the position on the contractility curve (more initial stretching of myofibrils)

Also reduces pulmonary capillary hydrostatic pressure
- Reduce pulmonary oedema

Question 3

How does reducing afterload help treat cardiac failure?

Answer 3

Increase stroke volume

by increasing the amount ejected during systole

Question 4

How does increasing contractility help treat cardiac failure?

Answer 4

more contraction = higher stroke volume

Question 5

What is increasing contractility at the expense of?

Answer 5

Cardiac work

Question 6

What are the drug classes used in heart failure?(4)

Answer 6

Vasodilators
Diuretics
Postive inotropes
Cardio-inhibitors

Question 7

What are some examples of vasodilators used in heart failure?

Answer 7

ACEIs / ARBs / nitrates / PDEIs

Question 8

What is a PDEI?

Answer 8

A phosphodiesterase inhibitor
a drug that blocks one or more of the five subtypes of the enzyme phosphodiesterase (PDE)
preventing the inactivation of the intracellular second messengers cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) by the respective PDE subtype(s).

Question 9

What are some examples of diuretics used in heart failure?

Answer 9

Loop / thiazides / MRAs (spironolactone, potassium sparing diuretics)

Question 10

What is an MRA?

Answer 10

mineralocorticoid receptor antagonist
aldosterone antagonist

increase sodium excretion
reduces extracellular fluid volume

Question 11

What is the mechanism of a thiazide diuretic?

Answer 11

inhibit sodium reabsorption in the DCT

Question 12

What is the mechanism of a loop diuretic?

Answer 12

sodium-potassium-chloride cotransporter in the thick ascending limb
NKCC in Loop of Henle
increase water loss and sodium loss
reduce extracellular fluid volume

Question 13

What are some examples of positive inotropes used in heart failure?

Answer 13

beta agonists / PDEIs / digoxin / levosimenden

Used acutely and closely monitored

Question 14

What are some examples of cardio-inhibitors used in heart failure?

Answer 14

beta blockers

Question 15

What is the difference between beta-agonists and beta-blockers

Answer 15

Overall, the effect of β-agonists is cardiac stimulation (increased heart rate, contractility, conduction velocity, relaxation) and systemic vasodilation.
Increase contractility.

β-blockers prevent binding of adrenaline and noradrenaline, inhibiting normal sympathetic effects

Question 16

Management of confirmed heart failure with reduced ejection fraction (systolic)

Answer 16

Ensure drugs which may cause or worsen heart failure are reviewed and stopped if appropriate

Loop diuretic - reduce symptoms of fluid overload
- titrate dose and adjust as new medications added

Prescribe both an ACE Inhibitor and a Beta-Blocker

• only start one at a a time
• —-ACE first in diabetics or signs of fluid overload
• —-NOT ACE in person with clinical suspicion of haemodynamically significant valve disease
• —- if unable to tolerate ACE, give ARB
• ——-Beat blocker first if person has angina

If BB + ACE doesn’t work, refer to cardiology

consider anti-platelet in people with atherosclerotic arterial disease
consider statin if indicated
ensure comobidites and causes are managed

screen for depression/anxiety

supervised exercise group
assess nutrition status

influenza and pneumococcal vaccine

Question 17

Management of heart failure with preserved ejection fraction (diastolic)

Answer 17

Ensure drugs which may cause or worsen heart failure are reviewed and stopped if appropriate.

Prescribe a loop diuretic - up to 80 mg furosemide (or equivalent), if necessary, to relieve symptoms of fluid overload.

Refer the person to a specialist for further advice on management.

consider anti platelets and statins

ensure comorbidities and causes are treated

screen for depression and anxiety

supervised exercise group and nutritional advice

influenza (annual) and pneumococcal (once) vaccines

Question 18

Side effects of ACE inhibitors

Answer 18

Dry Cough
Angioedema 
- above both from kinin build up - 
Hypotension
Renal compromise - hyperkalaemia, impaired autoregulation

Question 19

Side effects of ARBs

Answer 19

Symptomatic hypotension
Hyperkalaemia
Delayed onset angioedema

Doesn’t suppress aldosterone, no kind side effects

Question 20

Side effects of loop diuretics

Answer 20

Hyponatraemia
Hypokalaemia
Deafness
Renal toxicity (with dehydration)

Limited effectiveness alone

Question 21

Side effects of MRAs

Answer 21

Hyperkalaemia
Gynaecomastia (competes with testosterone at receptor)
Limited effectiveness alone

Question 22

MRAs and Loop Diuretics have limited effectiveness alone, how is this combatted?

Answer 22

given together

spironolactone with furosemide

Question 23

Side effects of Beta-agonists

Answer 23

Tremor
Headaches
Tachycardia

Not effective in Chronic heart failure
- only used in acute heart failure with reduced ejection fraction

Question 24

Side effects of PDEIs

Answer 24

Hypotension - vasodilation
Reflex tachycardia
Arrhythmias

Worsens survival in chronic heart failure

Question 25

Mechanism of cardiac glycosides (digoxin)

Answer 25

ion exchange in the cardiac myocyte
inhibit sodium/potassium pump
secondary inhibition of sodium/calcium exchange
rise in intracellular calcium - positive ionotropicity

slows AV conduction

Question 26

Side effects of cardiac glycosides (digoxin)

Answer 26

Arrhythmias

Contraindicated

• hypokalaemia (alters toxicity level of digoxin)
• renal impairment
• AV block

Question 27

Side effects and Unwanted effects of beta-blockers

Answer 27

Worsens contractility acutely
Bronchospasm in asthmatics
Cold hands and feet
Fatigue

Tachycardia
Increased cardiac work
Arterioconstriction
Venoconstriction
Renin release
- sympathetic nervous system -

Question 28

Which beta-blockers have specific advantages?

Answer 28

Bisoprolol - highly selective to beta-1 receiptors - main BB
Carvedilol - also has mild alpha-1 receptor blocking action
Nebivolol - highly selective for b1 receptors, enhances vasodilatation mediated by nitric oxide