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44 Cards in this Set
- Front
- Back
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What normally goes wrong with the equation of CO in HF?
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Decreased stroke volume
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What is a cause of high output cardiac failure?
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Long-term severe hyperthyroidism
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How does the body compensate for decreased CO? What are the mechanisms?
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Increased BP
Increased blood volume Increased HR Increased SV SNS, renal mechanisms |
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What is the most important stimuli for the release of aldosterone?
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ATII
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What are the main groups of drugs for the treatment of HF?
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Afterload reducers (incl. ACE inhibitors)
Beta blockers Diuretics Positive inotropes |
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What are some examples of positive inotropes in the treatment of HF?
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Digoxin
Sympathomimetics |
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What is the standard combination therapy for severe, chronic CHF?
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ACE modifier + Beta blocker + Diuretic
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What are some afterload reducing drugs in CHF?
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ACE inhibitors
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What are the contraindications for ACE inhibitors?
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Pregnant
Severe renal artery stenosis |
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What are the adverse effects of ATII in HF?
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Increased peripheral vascular resistance
Increased aldosterone release Vascular, cardiac hypertrophy and remodeling |
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What are the side effects of ACE inhibitors?
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Hacking cough
Angioedema Swelling of oraltissues Embryotoxic |
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Would you prescribe just a diuretic for the treatment of HF?
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No. They're used as adjuncts for other drugs.
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What is a negative side effect of diruetics?
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Hypokalemia
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What are the physiologic effects of diuretics?
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Decreased circulating fluid volume
Decreased edema, ascites Decreased BP |
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What's the mechanism of spironolactone (aldactone)?
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Competitive aldosterone receptor blocker
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What's the physiologic effect of spironolactone?
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Shedding of Na and H2O by the blocking of the aldosterone receptors
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What's different about spironolactone than other diuretics?
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Spares K
Less effecacious than the other diruetics |
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How should you dose beta blockers in HF?`
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SMALL DOSES!
Avoid using with other drugs that decrease HR/SV |
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What beta blocker is especially good for use in CHF? What's the mechanism?
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Carvediol
Nonselective B blocker (also blocks alphas) |
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What is the archetypical inotropic agent in CHF?
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Digoxin
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Why should you not switch around the form of Digoxin that you're giving your patient?
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There is different bioavailabilities in the different dosages...so don't pull a switcheroo!
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Does digoxin provide a mortality benefit to patients?
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No - only symptomatic relief
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What are problems associated with using Digoxin?
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Small therapeutic index
AV block Long-term toxicity due to K-wasting diuretics that are commonly co-prescribed |
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Generally, what's the half-life of digoxin? Why should you consider this?
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36-40 hours...it stays around for a while
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What is the mechanism of digoxin?
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Binds to and inhibits the Na-K ATPase-->indirect increase in intracellular Ca(2+)--> increased contractile force, increased CO
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What ion effects the binding of digoxin? How?
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K
Binding is DECREASED with elevated extracellular potassium Binding is INCREASED by decreased extracellular K Inverse relationship between K amount and binding |
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Why is it that intracellular Ca levels rise with Digoxin? Doesn't it inhibit the Na/K ATPase?
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Increased Ca due to the fact that a Na/Ca nonselective transporter is now flooded with all of the extra Na, meaning that a bunch of the Ca is stuck inside the cell
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What are the main cardiac electrophysiologic effects of digoxin?
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Increased conduction rates through, and the automaticity of the atria, ventricles
Decreased conduction through the AV node: increased PR interval |
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When should you use digoxin as an antiarrhythmic?
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When you're having AV nodal reentrant tachycardias
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What are the direct hemodynamic effects of Digoxin?
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Direct: Increased SV
Indirect: Decreased SNS activity Decreased activation of R-A-A system Decreased renal Na, H2O retention |
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What is the rate of toxicity in px. who are on digoxin long-term?
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50%!!!
SO HIGH! |
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What is the cause of digoxin toxicity?
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Hypokalemia
Caused by use of K wasting diuretics (Remember, increased Digoxin binding with lower extracellular levels of K!!!) |
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What are the cardiac symptoms of Digoxin toxicity?
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2nd, 3rd degree AV block
Arrhythmias |
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Other than K+ wasting diuretics, what are other causes of increased sensitivity to Dig?
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Sympathomimetics (increased risk of ectopic ventricular beats)
Hypothyroidism (more intense AV nodal depression) Hypoxia MI Decreased renal function |
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What are the extracardiac symptoms of Digoxin toxicity?
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chromatopsia (color changes)
nausea/vomiting anorexia lethargy |
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How do you treat Dig toxicity?
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Stop the drug!!!
Correct electrolyte levels Lidocaine (IV) for arrhythmias Digoxin antibody |
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What drugs/conditions decrease Digoxin's effects?
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Diarrhea
Laxatives Antacids Cholestryamine Hyperkalemia |
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What are drugs/conditions that increase digoxin's effects?
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Hypokalemia
Beta blockers CCB's (Non DHPs) |
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What kinds of drugs should you use in acute heart failure?
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Diuretics
Positive inotropes Vasoconstrictors |
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What are some positive inotropes used for acute HF?
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Dobutamine
Dopamine Norepi + alpha blocker |
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What are some afterload reducers/preload reducers that you should think about using in acute HF?
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Nitroprusside
NTG Hydralazine Long-acting CCBs |
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When do you use Milrinone? How is it administered?
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Acute HF
IV |
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What are the physiologic effects of milrinone?
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Positive inotrophic effects
peripheral vasodilation |
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What is the mechanism of action for milrinone?
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Inhibition of phosphodiesterase (can't break down cAMP)
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