What class of drug is Flecanide ?
Flecanide blocks what stage of the non-pacemaker action potential?
Flecanide is a sodium channel blocker
it blocks the fast voltage gated Na+ channels (initial rapid depolarisation phase)
decreasing the size of AP/depolarisation
effect of flecanide on AP?
class 1C - soidum channel blocker
slows depolarisation of the myocyte (rapid depolarisation phase)
shortens plaque phase
How do cardiac specific beta blockers work (e.g. bisoprolol)
block B1 receptors in myocardium
block sympathetic stimulation
How does bisoprolol (cardiac specific beta-blocker) effect the AP of cardiac muscle cells
prolongs depolarisation (from resting potential) /discharge of SA/ conduction in AV node
reduces excitability of non-nodal tissue
shortens plaqteau phase (reducing contractility)
First choice for atrial fibrillation
Bisoprolol (beta-blocker) cardio specific
how do beta blockers effect the slow plateua phase of cardiac AP?
reduces contractility!
how do beta blockers effect the depolarisation of cardiac cells?
slows the discharge from SA node and AV node conduction
also reduces excitability of non-nodal cardiac tissue
why are beta-blockers now first line in AF treatment
flecanide is a sodium channel blocker
a. true
b. false
a. true
what is the mechanism of action of Amiodarone
class 3 anti-arrhymic
potassium channel blocker
amiodarone is a calcium channel blocker
a. true
b. false
b. false
is a potassium channel blocker
What effect does amiodarone have on cardiac AP
(is a potassium channel blocker)
how does amiodarone increase the duration of the AP of cardiac cells?
by prolonging the repolarisation (phase 3) -
there is K+ channel blockade (prevents K+ efflux)
(increases refractory period)
Amiodarone is a sodium channel blocker
a. true
b. false
b. false
Potassium channel blocker (prevents repolarisation) - prolongs AP
Amiodarone is used to control difficult to treat arrythmias (e.g. life threathening V-Tach or V-Fib)
a. true
b. false
a. true
when resistant to other drugs
When is amiodarone most likely to be used
VT and occaisonally difficult to treat SVTs (A-fib)
Side effects of amiodarone ( - K+ channel blocker)
a drug that amiodarone interacts badly with (that is also used for anti-arrythmias)
similar affect with verapamil
What class of drug are verapamil and diltiazem
calcium channel blockers
what phase of the AP of cardiac cells do CCBs (verapamil and diltiazem) affect
bind to L-type voltage gated channels
Verapamil slows the heart rate
a. true
b. false
a. true
Calcium channel blocker
reduces contractility and slows AV
Verapamil is more effective for Atrial fibrillation at high HRs
a. true
b.false
a. True
CCBs show use dependence
- more effective at higher HR
digoxin properties
cardiac glycoside
inhibits sodium potassium ATPase pump