Cardiac Pharmacology Part 2 Flashcards
What is ejection fraction ?
percentage of blood volume at the end of diastole that is ejected from the ventricle for each heartbeat
What is the Frank-Sterline law of heart ?
the myocardial fibers stretch during diastole
- increasing diastolic volume leads to an increase in the force of contraction
What is inotropy ?
affects the force of contraction of the heart muscle
- (+): increase contractility
- (-): decrease contractility
What is chronotropy ?
affects the rate of contraction by affecting the nerves controlling the heart, or by changing the rhythm produced by the SA node
- (+): increase HR
- (-): decrease HR
What is dromotropy ?
affects the conduction speed in the AV node, and as a result the rate of electrical impulses in the heart
- often used for arrhythmias
- (+): increases conduction speed
- (-): decreases conduction speed
What are some characteristics of Norepinephrine (Levophed) ?
increases vasoconstriction of the veins and arterioles
- increases BP and HR
- increases afterload
- (+) inotrope: increase contractility
- long term use not recommended as can result in tissue ischemia
What are some characteristics of Epinephrine ?
(alpha 1, beta 1&2 adrenergic agonists) increases vasoconstriction of arterioles and veins
- increases BP and HR
- vasodilation of arterioles and veins in heart and lungs
- vasodilation of bronchi
- positive inotrope, chronotrope, dromotrope
- used in cardiac arrest, allergic reactions, and shock
What are some characteristics of Doxazosin ?
(alpha 1 adrenergic antagonist) block vasoconstriction of arterioles and veins, therefor vasodilates
- decreases BP
- decreases afterload
- SE: hypotension, sodium retention
What are some characteristics of dopamine ?
(beta 1 adrenergic agonist)
- increases HR, contractility, conduction, and renal perfusion
(alpha 1 adrenergic agonist)
- increase BP and HR
Positive inotrope
- increases contractility= increased cardiac output
- IV infusion given in ADHF and shock
What are some characteristics of Dobutamine ?
(Beta 1 adrenergic agonist)
- increases HR, contractility, conduction
(Beta 2 adrenergic agonist (mild))
- mild vasodilation of arterioles and veins in heart and lungs
(alpha 1 adrenergic agonist)
- increase BP and HR
(positive inotrope)
- increases contractility= increased CO
IV infusion given in ADHF
What are some characteristics of Nesiritide ?
IV infusion used to treat acute decompensating heart failure
- balances arterial and venous vasodilation (reduced afterload)
- promotes natriuresis (sodium depletion)
- SE: potent vasodilator so watch BP closely
What are some characteristics of Milrinone ?
IV infusion used to treat acute decompensating heart failure
- promotes arterial vasodilation (reduces afterload)
- Positive inotrope: increases contractility
- Class: phosphodiesterase inhibitors
What are some characteristics of Digoxin ?
Class: cardiac glycosides
- Positive inotrope: increases contractility
- negative chronotrope: decreases HR
- negative dromotrope: prevents arrhythmias
- monitor blood levels for toxicity: normal levels <2, K+ must be >4
- can cause life threatening dysrhythmias so no used frequently in adults (more common in peds)
What are some characteristics of nitroglycerin ?
given for chest pain and/or high BP
- beneficial in acute decompensated HF
- relaxes vascular smooth muscles around veins and arteries leading to vasodilation
- must protect bottle from sunlight, comes in glass bottle, need brown bag over bottle, needs blue tubing
What are some characteristics of morphine ?
used in acute decompensated heart failure to treat anxiety
- causes peripheral vasodilation
- SE: respiratory depression
What are some characteristics of Isosorbide Dinitrate & Hydralazine ?
combo meds used as frontline treatment in black pt’s with HF
- Isosorbide Dinitrate: long-acting nitroglycerin
- Hydralazine: arteriolar vasodilator
- decreases preload and afterload
What are some characteristics of calcium channel blockers ?
dilates coronary arteries
- negative ionotropic effect: decreases contractility (NOT FOR PT’S WITH HF)
- negative dromotropic affect: decreases conduction
- Ex.) Diltiazem, nifedipine, verapamil
