L14: HF Flashcards
Why DO diseased hearts see an increase in CO with digitalis
PVR is already maxed out (sympathetic tone), can’t increase more to counteract contractility
Don’t give beta blockers with
dobutamine
dopamine
At any point if a patient shows signs of digoxin intoxication
discontinue
IF moderate to severe, give K+
IF severe, give Digitalis Immune Fab
4 drugs that are positive inotropes (increase contractility)
Digoxin
Dobutamine
Dopamine
Milrinone
Why is contractility decreased in HF
myocardial muscle fibers are stretched too far as ventricles become dilated
Main side effect that occurs with ACE inhibitors but not ARBs?
Dry cough due to increased bradykinin
Milrinone is given short term due to
Risk of arrhythmias
IV only
why DON’T normal hearts see an increase in CO with digitalis?
Increased PVR counteracts the increased contractility
Reduce preload with
venodilators
Earliest signs of digoxin toxicity?
GI effects - even at low doses
Disappear after discontinuation
Sacubitril/valsartan contraindication
pregnancy
Cardioversion treatment is for
vfib caused by severe digitalis intoxication
Reduce afterload with
arteriodilators
ACE-I contraindication
Pregnancy
Milirinone indications
palliative care for acute HF or severe exacerbation of chronic HF
IV only
Bigemy
induced by digitalis, treated with K+
Drugs to increase contractility
Inotropic drugs
Digoxin MOA
Inhibition of membrane sodium pump (Na/K ATPase) leading to cardiac effects:
- Increased intracellular Na+
- Increased intracellular Ca2+ leads to increased SR Ca2+ stores
- Increased actin-myosin interaction by intracellular Ca2+
most common cause of digitalis death
vfib
All glycosides are
toxic
digoxin is a cardiac glycoside
Most heart failure is
left ventricular dysfunction
Beta blockers in late heart failure… (Carvedilol, Metoprolol)
DANGER: negative inotropic effet
Digoxin can be displaced from tissue binding sites (increased toxicity) by
Quinidine (careful if your patient has HF and arrhythmias!)
Most common and dangerous side effects of Digoxin?
Arrhythmias: sinus bradycardia, ectopic ventricular beats, AV block, and BIGEMINY
Things that decrease digitalis toxicity/effects
- Decreased GI absorption: cholestyramine, bran
2. Calcium Channel Blockers→ decreased contractility→ contraindicated in heart failure
Beta blockers in early heart failure… (Carvedilol, Metoprolol)
decrease mortality
What is the most important role of the neprilysin inhibitor in the Sacubitril/Valsartan combo?
Reduced sodium retention
Also: reduced vasoconstriction and cardiac remodeling
Sodium nitroprusside effects
venous and arteriodilator
MOSTLY VEINS
Hydralazine effects
vasodilation by NO
Preload increases because
Increased sympathetic and RAAS activity —> Increased venous return —> Increased blood volume and venous tone
When to use Ivabradin
It decreases HR when beta blockers can’t/won’t
Afterload increases because
Increased sympathetic and RAAS activity —> increased peripheral resistance via arterial constriction
Drugs to reduce contractility
B blockers
Main side effects of Sacubitril/Valsartan?
Hypotension
Hyperkalemia (from the ARB)
COUGH and ANGIOEDEMA (increased bradykin)
Diuretics to decrease mortality
spironolactone
eplerenone
aldosterone inhibition is beneficial
Things that increase digitalis toxicity
- Decreased renal clearance or volume of distribution: quinidine, amiodarone, captopril, verapamil, diltiazem, cyclosporine
- Quinidine displaces digoxin from tissue binding sites
- Increased digoxin GI absorption: erythromycin, omeprazole
- Hypokalemia: thiazide/loop diuretics, diarrhea
- Decreased SA/AV node activity: beta blockers
- Myocardial sensitization to digoxin: NE releasing agents
Monitor ______ when on digoxin therapy
PERFORM REGULAR EKGS, MEASURE K+ and DIGITALIS
Isosorbide dinitrate is a…
precursor of nitric acid
