Heart Failure Flashcards
What causes sudden death in heart heart failure?
Arrhythmias
What are the main determinants of cardiac workload?
Preload
Afterload
Contractility
HR
What kinds of drugs decrease preload?
Venodilators
What kind of drugs reduce afterload?
Arteriodilators
What effect do B-blockers have on contractility
Decrease conractility
How do B blockers reduce cardiac work?
Slowing HR
When your heart is failing, what happens to preload
Increases due to increased blood volume and increased venous tone
What 2 classes of drugs will reduce preload in HF
Diuretic
Venodilators
What effect does HF have on afterload
Increased afterload due to increased aortic impedance and increased arterial constriction
What class of drugs will reduce afterload in HF
Arteriodilator
What effect does HF have on HR
HR is increased due to reflex tachycardia caused by sympathetic hyperactivity
How do B-blockers help in HF
They reduce energy expenditure by slowing the HR
Does not help in end stage HF
What is the MOA of digoxin?
Inhibits the Na+,K+ ATPase pump on the cell membrane. Leads to:
⬆️Intracellular Na+
⬇️Expulsion of intracellular Ca++
⬆️Intracellular Ca++ leads to increased Ca++ stores
⬆️Actin-myosin interaction by intracellular Ca++
⬆️Contractility (positive inotropy)
What is the #1 drug to increase inotropy
Digitalis
What effect does Digoxin have on normal healthy hearts
Decreases HR
Who can use Digoxin as an antiarrhythmic?
Patients NOT in heart failure!
How does Digoxin slow HR in normal hearts?
Vagal stimulation due to:
Sensitization of arterial baroreceptors
Stimulation of central vagal nuclei
Increased SA node sensitivity to ACh
How does Digoxin slow HR in FAILING hearts?
In HF, sympathetic tone will already be high, but Digitalis will reduce sympathetic tone by increasing myocardial contractility
Does Digitalis increase Cardiac output for everyone?
No, only in failing hearts.
Because peripheral vasoconstriction will increase in normal people
What is one of the earliest sign of digitalis toxicity?
GI side effects***
Will disappear after discontinuation
Is the margin of safety wide or narrow in digoxin
Narrow, you can have toxicity even at therapeutic doses
Is Digoxin a glycoside?
Yes, and all glycosides are toxic
What is the most dangerous adverse effect of digoxin?
Cardiac arrhythmias!!!**
Includes: BIGEMINY**, sinus bradycardia, AV block, ectopic ventricular beats
How do you treat a ~moderate~ digoxin intoxication
Stop drug and give potassium
How do you treat SEVERE digoxin intoxication (life-threatening arrhythmias)
Stop drug, give potassium, and give Digitalis Immune Fab (Digibind)****
Do NOT cardiovert digitalis-induced arrhythmias unless Vfib
If digitalis has caused an arrhythmia, can you cardoivert them?
No
Not unless it is Vfib
What drugs will increase the toxicity of digoxin?
Thiazide and Loop diuretics!!**
Quinidine- displaces digoxin from tissue binding sites
Why do thiazides and loop diuretics increase the toxicity of digoxin?
They cause hypokalemia!!!***
Hypomagnesemia** and Diarrhea could also increase toxicity since they reduce K+
What effect will hypomagnesemia have on digoxin toxicity
Increased
What drug class will decrease the effectiveness of digoxin
Calcium channel blockers lol they will literally DECREASE contractility and are CONTRAINDICATED in HF
What kind of drug is Milrinone
An “inodilator”
Increase inotropy AND causes vasodilation
What is the MOA of milrinone
Inhibits cAMP phosphodiesterase
Leads to increased cAMP, increased Ca influx and a significant vasodilating effect
what is the the route of administration of milrinone
IV only
What do we use Milrinone for?
Palliative treatment for acute HF or severe exacerbation of chronic HF (IV only, SHORT TERM use)
How long can a patient be on milrinone?
SHORT TERM
Long term will kill them via an arrhythmia
What is the adverse effect of milrinone
Arrhythmia
What drug would be pointless to give at the same time you gave dobutamine or dopamine
B Blocker
What is the MOA of dobutamine and dopamine
B1 agonists- causes an inotropic effect
What are the 2 benefits of spironlactone and eplerenone
Reduce mortality rate
Correct hypokalemia caused by loop/thiazide
How do ACEs and ARBs treat Heart failure
Diminish cardiac workload by:
Reduce edema and preload (inhibit aldosterone)
Decrease afterload via Vasodilation (inhibit Angiotensin II)
Why do ACEs cause a cough
They reduce the bradykinin metabolism
Are ACEs/ARBs OK in pregnancy?
NO
Category X in 2nd and 3rd trimester!
What does Sacubitril/Valsartan (Entresto) do?
Valsartan: ARB
Sacubitril: neprilysin inhibitor (results in more vasodilation)
Which is better at reducing mortality in HF: Sacubitril/Valsartan (Entresto) or Enalapril alone
Entresto
What effect do B-blockers have on life expectancy in HR
Increase life expectancy ONLY in early stages of HF
Dangerous in endstage due to negative inotropic effect
What drug is the “sweetheart” of cardiologists and why
Carvedilol. It is a nonspecific B blocker AND an a1 blocker so it will decrease peripheral resistance in addition to the B blocker effects
What effect does Sodium nitroprusside (Nitropress) have
Dilates VEINS more than arteries. (Same thing as nitro)
What does Isosorbide dinitrate and Nitroglycerin do?
Dilates veins more than arteries
Reduces preload more than afterload
What does Hydralazine do?
Peripheral vasodilation via the production of NO
