INOTROPIC
•Contractility
•Cardiac Muscle
•+ increase the FORCE of myocardial contraction (STRENGTH)
•- decrease the force
•CHRONOTROPIC
•Heart rate
•SA Node
•+ increase the RATE of the heart beat
•- decrease the RATE of the heart beat
•DROMOTROPIC
•Conduction Velocity
•AV node ,bundle of His, Purkinje Fibers
•+ increases CONDUCTION of electrical impulses
- decreases CONDUCTION of electrical impulses
Note: Heart failure patients should weigh in daily!
◦If 2 lb weight gain in 1 day OR 5 lb in 1 week, need to notify provider (developing fluid
overload) - correct answer-Heart failure definitions
Used to treat:
◦1) Heart Failure (negative chronotropic)
◦2) Atrial Fibrillation (negative dromotropic, negative chronotropic)
-Adverse effects:
◦Due to Digoxin + Potassium competing, we must have normal potassium levels
(magnesium and calcium too)!
◦Dig Tox= Hypokalemia, Hypomagnesemia, HYPERcalcemia
◦CNS related-
Fatigue, Confusion
◦Vision disturbances- yellow tint, "Halos", blurred vision•
What can cause toxicity?◦hypokalemia, hypomagnesemia, hypercalcemia
◦Digoxin Normal range (narrow therapeutic drug)= 0.5 -2 ng/ml
HOW TO TREAT TOXICITY?
◦What if we see EKG changes or symptomatic?-
Check a digoxin level
◦ANTIDOTE-
Digibind ®- Digoxin specific A - correct answer-Digoxin
P - phenytoin
S - Smoking
P - phenobarbital
O - Oxcarbazepine
R - rifampin
C -carbamazepine
S - St. John's Wort (OTC herb) - correct answer-Inducers: PS - PORCS
P - protease inhibitor (HIV)
A - azole antifungal (fluconazole,ketoconazole)
C - cimetidine
M - macrolides (Azithromycin ACE?)
A - amiodarone
N - non-DHP Calcium Channel Blockers (diltiazem, verapamil)
♥'s
Grapefruit juice - correct answer-Inhibitors: PACMAN loves Grapefruit juice!
In general, heart failure patients should weight in daily! If 2 lb. weight gain in 1 day OR 5 lb.
in 1 week, NEED TO NOTIFY PROVIDER (fluid overload development)
Goals for treatment:
1) If fluid overloaded- remove excess fluid (loop diuretics such as furosemide)
2) Increase cardiac output to reduce end organ dysfunction
◦Inodilator:
◦Milrinone
◦Inotropic Support:
◦Dobutamine/Dopamine - correct answer-Heart failure exacerbation
Manifested by muscle weakness, confusion, lethargy, anorexia, nausea, and changes in the
ECG - correct answer-Hypokalemia
1) POSITIVE INOTROPIC activity- Blocking the Na+/K+ ATPase pump (treats HF by helping
heart pump more blood out to the rest of the body, such as kidneys)
2)NEGATIVE CHRONOTROPIC activity- Digoxin has been found to be
parasympathomimetic (causes vagal stimulation) and also increases baroreceptor sensitivity
(treats atrial fibrillation by slowing heart beat down)
3) NEGATIVE DROMOTROPIC activity- Cholinergic activation in atria (AV node), less at
Purkinje (treats Atrial fibrillation by slowing down any crazy rhythms)
RESULT?- Improved Cardiac Output and Increased Renal Perfusion= Increased Urine
Production and decreased RAAS activation - correct answer-Digoxin mechanism of action
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