CVS - heart failure

Question 1

effects of heart failure

Answer 1

heart pumps less effectively -> more blood remains in the ventricles (increase preload) -> heart becomes overstretched and contracts less forcefully
- decrease CO
increase venous pressure -> - decrease GFR
water and electrolytes retention -> edema

Question 2

3 groups of CHF therapy

Answer 2

1. inotropic drugs - for the heart to pump more efficiently
2. vasodilators
3. misc
   CHF tend to have poor prognosis :(

Question 3

Inotropic drugs

Answer 3

• glycosides
• beta agonists
• PDE inhibitors (antithrombotic)

Question 4

Vasodilators

Answer 4

(ANALS)

• sodium nitroprusside (SNP)
• nitrates
• ATR1 antagonist
• loop diuretics
• ACE inhibitors

Question 5

nitroprusside clinical use

Answer 5

chronic/ refractory HF

IV - allows for careful monitoring for ADR

Question 6

nitroprusside ADR

Answer 6

• hypotension
• cyanide poisoning (SNP is made of cyanide)
• methemoglobin causing hypoxia (SNP is made up of methemoglobin) - decrease O2 binding capacity of RBC

Question 7

loop diuretics

Answer 7

• Inhibit Na+/K+/Cl- cotransporter in thick ascending limb of LOH
• Decrease reabsorption of Na+
• Activation of RAAS system -> increase GFR
• Also inhibit Mg2+ and Ca2+ reabsorption
• Increase excretion of Mg2+ and Ca2+
• Induce renal prostaglandin synthesis
• Increase renal blood flow
• High conc of solutes in collecting duct -> decrease osmotic drive - decrease water reabsorption -> increase urination

Question 8

loop diuretics drugs

Answer 8

• furosemide
• bumetanide
• ethacrynic acid

Question 9

loop diuretics clinical use

Answer 9

• acute pulmonary edema/ all edema
• acute hyperkalemia
• acute renal failure
• anion overdoes - through toxic ingestion
  IV - rapid absorption

Question 10

glycosides drugs

Answer 10

digoxin

digitoxin

Question 11

glycosides effects

Answer 11

• increase contractility - decrease preload and afterload
• increases parasympathetic activity -> decrease AV conduction -> increase PR interval, decrease ventricular rate
• increase intracellular Ca2+

Question 12

glycosides clinical use

Answer 12

• systolic (ventricular contraction) dysfuction

- atrial fibrillation

Question 13

glycosides ADR

Answer 13

• GIT: anorexia, nausea, vomitting
• CNS: headache, fatigue, confusion, blurred vision
• could potentially cause more dysrythmia - through AV block

Question 14

how to deal with digitalis toxin

Answer 14

discontinue glycosides

lidocaine, propanolol

Question 15

when to use digoxin vs digitoxin

Answer 15

if pt has liver failure: use digoxin - digitoxin metabolised by liver
renal failure: use digitoxin - dioxin excreted renally