Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharm II > Antiarrhythmics > Flashcards

Antiarrhythmics Flashcards

1
Q

Electric potential

A

Amount of work needed to move a unit of positive charge a fixed distance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Action potential

A

Change in membrane potential associated with the passage of an impulse along the cardiac syncytium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Explain how cardiac myocytes are connected

A

Portions of the cell membrane contain intercalated disks which have gap junctions

The junctions form channels between cells and allow depolarizing current to flow from one cell to the next

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What do we call the transmission of action potentials that allows for coordinated contraction?

A

Electric coupling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Duration of cardiac action potential

A

0.2 seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Amplitude of cardiac action potential

A

100 mV

-80 to +20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

3 types of channels involved in cardiac cell action potentials

A

Fast sodium channels

Voltage gated potassium channels

Slowwwww calcium channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Phase 0

A

Depolarization- Na fast channels open

Potential raises to threshold (-70) due to influx through gap junctions (na+ca)

That opens the fast channels and raises potential to +20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Phase 1

A

Early Repolarization- voltage gated potassium

K efflux

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Phase 2

A

Plateau- calcium channels open

Slow Ca influx- activates muscle contraction

Plateau created by balance of influx (Ca) and efflux (K)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Phase 3

A

Rapid (late) repolarization- continued K efflux

Calcium channels close, K channels close at end of this phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Phase 4

A

Resting potential

-90mV

Maintained by non-voltage K channels (leak)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is different about pacemaker cells?

A

Slow phase 4 depolarization

Only have phases 0,3,4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the basis for automaticity?

A

Phase four slow depolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do we classify antiarrhythmics?

A

Singh-Vaughan-Williams SVW

Based on electrophysiology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What drugs do not fall into the SVW classification?

A

Adenosine

Digoxin

17
Q

Class I SVW

A

Membrane stabilizing agents

Block Na channels

Delay phase 0 depolarization

18
Q

Class II SVW

A

Beta blockers

Decrease SA and AV activity

Decrease conduction

Decrease automaticity

19
Q

Class III SVW

A

Block potassium channels

Prolongs repolarization and refractory period

20
Q

Class IV SVW

A

Block Ca channels

Slower phase 0 of nodal action potential (slows conduction in AV and SA nodes)

21
Q

Normal automaticity arrhythmias

A
  • sinus tach, ventricular tach

regular rhythms with shortened phase 4 depolarization

treat with beta blockers

22
Q

Abnormal automaticity rhythms

A

Ectopic atrial tachycardia

Irregular, spontaneous impulse formation from partially depolarized cells

Treatment-calcium channel blockers

23
Q

(Triggered arrhythmias)

Early after-depolarization arrhythmias

A

Tornadoes de pointes

Caused by drugs that delay repolarization-long QT

Results in new action potential before myocyte has fully repolarized

Treatment: beta blockers or calcium channel blockers

24
Q

(Triggered arrhythmias)

Delayed after-depolarization

A

Digitalis toxicity

Action too early in phase 4

Typically caused by rise in calcium

Treatment: calcium channel blockers

25
Q

Reentrant Circuit Arrhythmias

A

Atrial flutter, SVT, VT

Occur when an area of the heart contains a region of slowed ion conduction

-normal conduction cannot go unidirectional but goes in a circle

Micro- one chamber macro- multiple

SVT-adenosine
Monomorphic VT- class Ia

26
Q

Fibrillation arrhythmias

A

Multiple microreentrant circuits in one chamber

AF: class Ia or III drugs

VF: amiodarone

27
Q

What is Amiodarone?

A

Class III Potassium channel blocker

Prolongs action potential and increases refractory period

28
Q

What is Diltiazam

A

Class IV calcium channel blocker

Slows AV nodal conduction

Can cause VF in WPW

29
Q

WPW- what is it

A

Accessory pathway that bypasses AV node allowing for rapid conduction between atria and ventricles

This results in classic delta wave and short PR interval

Pharm II (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions