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Pharmacology (5th year) > Cardiac Failure > Flashcards

Flashcards in Cardiac Failure Deck (29):
1

Definition of cardiac failure

A clinical syndrome characterised by systemic perfusion inadequate to meet the body's metabolic demands as a result of impaired cardiac pump function

2

Causes of cardiac failure

- IHD
- hypertension
- valvular heart disease
- CMO
- thyrotoxicosis
- alcohol
- anaemia

3

Frank-Starling law

The stroke volume of the heart increases in response to an increase in the volume of blood filling the heart, when all other factors remain constant

4

The chronic heart failure cycle

- LV systolic dysfunction
- increased end diastolic pressure
- compensatory responses (vent hypertrophy, RAAS)
- increased afterload
- pulmonary oedema

5

Actions of Ang II

- vasoconstrictor
- inhibits vagal tone
- promotes aldosterone production
- stimulates norepinephrine release from sympathetic nerve terminals

6

Therapeutic objectives of cardiac failure

- reduce symptoms
- treat reversible conditions
- correct aggravating factors
- modify disease progression
- reduce hospital admissions
- reduce sudden death

7

Drug classes used in heart failure

- Renin-angiotensin system blockers
- B-blockers
- diuretics
- inotropic agents

8

MOA of furosemide

- inhibits Na-K-Cl co-transporter in ascending loop

9

MOA of HCTZ

- inhibits NaCl channel in DCT

10

MOA of spironolactone

Aldosterone antagonist (in collecting duct)

11

Explain concept of low vs high ceiling diuretics

- low ceiling = maximal response achieved at relatively low dose (thiazides and spironolactone)

12

SEs of furosemide

- electrolyte disturbances
- ototoxicity
- dehydration
- metabolic alkalosis

13

SEs of Thiazide diuretics

- electrolyte disturbances
- hyperuricaemia and gout
- hypercalcaemia
- high doses (glucose intol and adverse lipid profile)

14

Chronic management of cardiac failure

Step 1 = ACE-inhibitor + diuretics
Step 2 = add Carvedilol (BB)
Step 3 = add spironolactone
Step 4 = add Digoxin

15

SEs of ACE-inhibitors

- hyperkalaemia
- hypotension
- renal failure (GFR falls)
- chronic dry cough

16

Contraindications for ACE-I

- renal artery stenosis
- pregnancy
- previous angioedema
- aortic stenosis

17

Management of ACE-I angioedema

- withdraw ACE-I
- supportive treatment
- corticosteroids, anti-histamines, adrenalin
- discuss use of ARB

18

Principles of starting B-blocker

- start with low dose and titrate up
- add to existing ACE-I + diuretics when stable
- never stop abruptly (risk ischaemia and infarction)

19

MOA of BB

- lower myocardial energy expenditure
- prolong diastolic filling
- increase myocardial blood flow

20

Short-term risks of BB

- worsening heart failure
- bradyarrhythmias
- prolonged intraventricular conduction
- hypotension
- worsening renal function

21

Relative contra-indications to BB

- HR <60
- symptomatic hypotension
- greater than minimal evidence of fluid retention
- signs of peripheral hypo-perfusion
- PR interval >0/24 sec
- 2nd or 3rd degree AV block
- Hx of asthma or reactive airways
- PAD with resting limb ischaemia

22

Effects of aldosterone in cardiac failure

- sodium and water retention
- promote cardiac fibrosis
- endothelial dysfunction

23

MOA of spironolactone

- aldosterone antagonist
- binds to mineralocorticoid receptor and decreases ENaC

24

When is spironolactone indicated?

NYHA III and IV despite treatment with ACE-I and B-blocker

25

SEs of spironolactone

- hyperkalaemia (dont give if K >5 or Cr >120)
- affinity for other steroid receptors (gynaecomastia, hirsuitism, sexual dysfunction)

26

MOA of digoxin

- inhibits Na/K ATPase in myocardium (increases intracellular Ca)
- increases vagal activity (inhibits SA node and delayed AV nodal conduction)

27

Indications for digoxin

- AF
- BB fail to control HR <70
- mod/severe symptoms despite optimal treatment

28

Features of digoxin toxicity

- GI: Nausea, vomiting, dirrhoea
- Neuro: confusion, facial pain, coloured vision, vertigo
- CVS: palpitations, arrhythmias, syncope

29

Drugs contraindicated in cardiac failure

- Direct negative inotropic agents
- TCAs (proarrhythmic)
- NSAIDs (inhibit diuretics)
- COX 2 inhibitors
- corticosteroids (water retention)