cardio 3

Question 1

what does Q-T represent

Answer 1

duration of AP

Question 2

what is the name given for ST elevation

Answer 2

ischemia

Question 3

should antiarrhythmic drugs have an effect on contractility

Answer 3

no

Question 4

describe the actions of each type of antiarrhythmic drug type

Answer 4

1a = reduce rate of rise of phase 0
lengthen AP
1b = reduce rate of rise of phase 0
shorten AP
1c = reduce rate of rise of phase 0
no effect on AP
II = sinus node
III = widen duration of AP
IV = AV node

Question 5

what is most common antiarrhythmic drug

Answer 5

amiodarone

Question 6

what are the class Ia drugs

Answer 6

quinidine procainamide dysopyramide

Question 7

class Ib drugs

Answer 7

lidocaine

Question 8

class Ic drugs

Answer 8

propafenone, encainide, flecainide

Question 9

how does lidocaine work

Answer 9

blocks Na channels, which increases threshhold
use dependent
slow rise of Phase 0

Question 10

how does lidocaine effect contracility

Answer 10

not much

Question 11

which arrythmias is lidocaine good for

Answer 11

ventricular but not supraventricular

Question 12

how does lidocaine effect automaticity

Answer 12

decrease

Question 13

what are some class II drugs

Answer 13

metroprolol and propanolol

Question 14

what effects do class II drugs have

Answer 14

negative inotropic and chronotopic

Question 15

what are the main effects of beta blockers

Answer 15

slow heart rate, decrease contraction

Question 16

how do class III drugs work?

Answer 16

prolong APD and refractory period, no effect on rise ti

Question 17

what is the action of class III drugs

Answer 17

potassium channel blockers

Question 18

how do class III drugs affect repolarization

Answer 18

delays

Question 19

which class is good for re-entrant arrythmias

Answer 19

class III / potassium channel blockers

Question 20

what are the 3 layers of the heart from centre to out

Answer 20

endo mid epi

Question 21

which area of the heart do class III drugs act on

Answer 21

endocardium

Question 22

what are the 3 class III drugs of interest

Answer 22

amiodaron dronedarone D-sotalol

Question 23

what is the duration of action of amiodarone

Answer 23

30 DAYS

Question 24

what is the 1/2 life of lidocaine

Answer 24

20 mins

Question 25

what causes the toxicity of amiodarone

Answer 25

iodine

Question 26

how does amiodarone effect refractory period

Answer 26

prolongs it

Question 27

why is dronedarone beneficial

Answer 27

no iodine atoms

Question 28

why isnt dronedarone used

Answer 28

failed athena trial

Question 29

what is D-sotalol

Answer 29

beta blocker AND class III
prolongs APD

Question 30

which class is most associated with TdP and why

Answer 30

class III because prolonging APD

Question 31

block of which channels induces LQT

Answer 31

HERG block

Question 32

which drug was withdrawn for producing TdP

Answer 32

seldane

Question 33

how did seldane cause TdP

Answer 33

terfanadine metabolized to fexofenadine by CYP3A4
poor metabolism results in excess terfenadine which blocks HERG

Question 34

what are class IV drugs

Answer 34

voltage dependent calcium channel inhibotirs

Question 35

what are some class IV drugs

Answer 35

verapamil and diltiazem

Question 36

how do class IV drugs effect conduction, HR and contractility

Answer 36

slows conduction
decreases HR
reduces contractility

Question 37

what is the caveat of class IV drugs

Answer 37

may shorten APD

Question 38

how do cardiac glycosides function as antiaryhtmatic drugs

Answer 38

shows AV conduction by increasing vagal tone
Na/K ATPase inhibitor, less Na gradient, less action of NCX, less Ca, reduce sympathetic tone