NURS 3550H Lecture 4: Digoxin 2018
28 Dec 2018
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Review reading chapter 48, first 3 pages. Cardiac remodeling causes decreased elasticity of the heart. Inhibitors of raas: ace-inhibitors, angiotensin receptor blockers, aldosterone receptor antagonists. Inotropic agents: -agonists (for early stages of hf less frequently used now), Digoxin (cardiac glycoside: used later in hf or in acute situations. Inhibits sodium / potassium atpase (sodium-potassium pump) in myocardium: causes intracellular calcium increase contractility (positive inotropic effect) Increased co leads to increased perfusion of kidneys causing diuresis. Failure causes the heart to stretch so much that it is unable to pump effectively. Failure plus digoxin allows for increased contractility strength: heart rate, reflex decrease in hr due to increase co, increase vagal nerve activity, decreased hr increases filling time and decreased cardiac workload. Renin release: decrease bp, increase uo (decreases blood volume, decrease sensitivity of baroreceptors, decrease sns activity, decreased vasoconstriction, hr.
