Week 6: Heart Failure Meds- Basics, Digitalis, PDE, Dopamine

what is heart failure

unable to pump well enough, fluid collects in lungs and peripheral tissues

what is total peripheral resistance (TPR)

resistance to which the heart has to pump blood into circulation

what is stroke volume

volume of blood pumped from ventricles per beat

what main things are happening in heart failure

decrease contractility, output, ejection fraction, filling

what are the compensatory responses to heart failure

increased sympathetic discharge, increased activation of renin-angiotensin system, increased ADH release

causes of heart failure

ischemic heart disease, HTN, valvular disease, cardiomyopathies, viral infection, toxins

symptoms of heart failure

tachycardia, decreased exercise tolerance, dyspnea, cardiomegaly, arrythmias, salt/water retention, edema, weight gain

left sided heart failure

left atria and ventricle cant handle return from lungs, pulmonary edema (systolic and diastolic HF)

right sided heart failure

right atria and ventricle cant handle blood returning from periphery (preload), peripheral edema, organ congestion

4 main goals of managing HF

dapen neurohumoral activation, pre/afterload reduction, decrease HR, increase cardiac contractility

drugs used for dampening neurohumoral activation (3)

ACE inhibitors/ARBS, beta blockers, mineralcorticoid receptor atagonists

drugs for pre/afterload reduction (3)

loop diuretics, vasodilators, phosphodiesterase inhibitors

main med used for decreasing HR

beta blockers

drugs for increasing cardiac contractility (3)

cardiac glycosides, phosphodiesterase inhibitors, dopamine and dobutamine

3 breakdowns of drugs for HF

positive inotropic drugs, vasodilators, miscellaneous drugs for chronic failure

digitalis glycoside is what type of agent

positive inotropic

digitalis glycoside function

increase mechanical pumping by increasing calcium concentration and inhibiting NaK ATPase pump

what does digitalis glycoside do to CO

increases it at rest and during exercise

main example of digitalis glycoside

digoxide

other mechanisms of action for digitalis

inhibitory effects on sympathetic NS, stabilize heart rate and slow impulse control, cause reflex stimulation on vagus n

how does digitalis have inhibitory effects on sympathetic nervous system

decrease sympathetic stimulation of heart and peripheral vasculature

how does digitalis stabilize hr

effect on sodium, potassium, calcium

treats arrhythmias

the reflex stimulation on the vagus nerve does what?

slows hr and conduction

adverse effects of digitalis

toxicity, gi distress, cns disturbances, cardiac events, visual disturbances

phosphodiesterase inhibitors function

inhibit the enzyme that breaks down CAMP in cardiac cells

as camp concentration increases

more ca is in cells, more forceful contraction of cardiac cells

what properties does phosphodiesterase inhibitors have

vasodilating, decreases the preload and afterload

side effects of phosphodiesterase inhibitors

vasodilation can lead to perfusion of heart and other organs if CO is low

dopamine and Dobutamine function

stimulate beta 1 receptors on myocardium to increase HR and CO

how to give dopamine and dobutamine

IV in severe cases of CHF