21-31 - Miocardial Ischemia Flashcards
chest pain due to inadequate blood flow and, therefore, inadequate O2 delivery to the heart muscle
angina pectoris
anginal pain is usually due to release of ______ and _________ onto nociceptive afferents
bradykinin
adenosien
precipitated by exercise, cold weather or emotional stress 2-10 min
angina
sudden onset > 30 min; associated with SOB, weakness, nausea, and vomiting
acute MI
three organic nitrates
nitroglycerin
isosorbide dinitrate
isosorbide mononitrate
MOA organic nitrates
prodrugs that undergo denitrification by mitochondrial aldehyde reductase to yield NO
How does NO cause vasorelaxation?
increase cGMP -> activates cGK1 -> increases mitochondrial calcium uptake -> decreases calcium influx -> phosphorylation and inhibition of MLCK (contractor)
how do you account for nitrate tolerance?
nitrate effects could be maintained using dosing regimens that allow for a nitrate-free or low-nitrate concentration for several hours each day
which nitrate does not undergo first-pass hepatic metabolism?
isosorbide mononitrate
which organic nitrate has the shortest half life?
nitroglycerin
organic nitrates are potent _____ in veins
vasodilators
decrease volume and preload
organic nitrates have _______ effect on peripheral vascular resistance
no effect
how do organic nitrates avoid ‘coronary steal’
little or no effect on the coronary resistance vessels
indications for sublingual nitrates
acute attacks angina
prophylactic therapy before angina leading activity
why would you use organic nitrates for CHF?
lower filling pressure without adverse effects on systemic BP
