The heart Flashcards
what do Ca ions pass through from the sarcoplasmic reticulum into the cell
ryanodine receptors (RyR2) 75-80% is from here vs 20-25% from depolarisation influx
what drugs influence heart rate
Beta blockers calcium channel blocker ivabradine
what drugs influence cardiac contractility
beta blockers calcium channel blocker
what are the classes of calcium antagonists
rate slowing (cardiac and smooth muscle action) non rate slowing (smooth muscle action and more potent)
what drugs influence myocardial oxygen supply
organic nitrates and potassium channel openers
how do calcium channel blockers work
decrease Ica decrease speed of entering of Ca into cardiac cells
how does ivabradine work
Decreases If reduces heart rate by inhibiting pacemaker current
how do beta blockers work
prevent binding to beta adrenoceptors
how do potassium channel openers work
decrease the amount of work the heart needs to perform by decreasing preload and afterload
what are the side effects of calcium channel blockers
constipation - Ca channels in the gut are also blocked bradycardia
what are the side effects of beta blockers
worsening of heart failure - increases TPR bradycardia cold extremities
what are the side effects of ivabradine
visual disturbances bradycardia
what are the side effects of potassium channel openers
ankle oedema headache/flushing palpitations
how do organic nitrates work
NO causes GTP to be converted to cGMP and lead to relaxation (directly stimulating relaxation) NO also promotes potassium channel opening
what are the side effects of organic nitrates
ankle oedema headache/flushing palpitations
how does digoxin work
inhibits Na/K ATPase pump by competing with K for binding this slows down heart rate force of contraction increases because Na builds up within the cell so Na-Ca exchange increases and Ca builds up within the cell
