rhythm
what can the arrhythmias treatment can alter? -correct answers -decrease/increase the
conduc on velocity
-alter the effec ve refractory period
-suppress abnormal automa city
do the ion channels have mul ple or only 1 states? -correct answers ion channels have mul ple
states (open, closed, or inac vated)
what is so special about state-dependent drugs? -correct answers the state-dependent drugs
have a higher affinity for one, or two, states over the other states
Is every state the same? -correct answers Hell nah. Each state is a different shape & drugs have
different affini es for different shapes.
why many arrhythmias have acquired a "Na+ leak"? -correct answers Physiologically due to
ischemic ssue
which type of medica on can then target the source of the arrhythmias? -correct answers state-
dependent Na+ channel blockers
nearly all the an arrhythmic causes what? -correct answers cause arrythmias
,what can lead to no arrhythmia in re-entry arrythmias? -correct answers if the retrograde signal
is terminated (completely inhibited)
what lead to promote arrhythmias in re-entry arrhythmias? -correct answers if the retrograde
signal is merely par ally inhibited (slowed)
how many classes does the an arrhythmic agent -correct answers 4 classes with miscellaneous
what is the med for class I? -correct answers Na+ channel blockers (three sub-classes: IA, IB, &
1C
what is the med for class II? -correct answers Beta-AR antagonists (Beta-blocker)
what is the med for class III? -correct answers K+ channel blockers
what is the med for class IV? -correct answers Ca2+ channel blockers
Are the classes are rigorous (nghiêm ngặc)? -correct answers No. Because many drugs have
mul ple roles.
who creates the classifica on of an arrhythmic drugs? -correct answers Vaughan-Williams
What is the common job of all the subclasses of Na+ channel blockade (class I)? -correct
answers -all subclasses decrease automa city in the SA node
-decreases phase 0 upstroke velocity
-decreases the number of open Na+ channels (conduc on velocity is decreased)
, -Good to treat V-tach
why all the subclasses decrease automa city in the SA node? -correct answers -because of the
increase in the threhold voltage, or reduc on in Em
-decrease phase 4 slope
what the Na+ channel blockade can importantly change? -correct answers Na+ channel
blockade can alter the voltage needed to defibrillate the heart
What type of pa ent that needed to take care of when using Na+ channel blockade? -correct
answers pa ent with implanted defibulators
What are the meds for subclass 1A of Na+ channel blockade? -correct answers -quinidine
(cadioquin, quinidex, cin-quin)
-procainamide (pronestyl, procanbid, procan)
-disopyramide (norpace)
what is the mechanism of Na+ channel blockade 1A? -correct answers lead to a moderate Na+
channel block & prolonged repolariza on through binding to open Na+ channels
what is class 1A tend to do as a state-dependent block? -correct answers prefer open channels
what does Na+ channel blockade 1A do to ERP? -correct answers -decrease the chance of
causing re-entrant arrhythmia
-increase the chance of causing Torsades de pointes
*what is ERP stand for? -correct answers early repolariza on pa ern