Brainscape's Knowledge GenomeTM

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


See full index

Pharmacology 2 > 1 - Antiarrhythmics > Flashcards

1 - Antiarrhythmics Flashcards

1
Q

What are cardiac arrhythmias caused by?

A
  • Disease
  • Cardiac injury
  • Drugs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are arrhythmias a result from?

A
  • Abnormal impulse formation
  • Abnormal impulse conduction
  • Combination of both
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the different types of arrhythmias?

A
  • Premature contractions - PVC’s or PACS
  • Tachycardia
  • Flutters - atrial flutter (300 bpm), re-entry
  • Fibrillations - uncoordinated contractions
  • Bradycardia - normal but slower
  • Heart block:
    • Complete - His purkinje system cut in half, atria & ventricles work independently
    • Partial - some more than others
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What do antiarrhythmic medications do?

A
  • Depress parts of the heart that are beating abnormally
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the pharmacological effects of antiarrhythmic medications?

A
  • Change of slope of depolarization
  • Raise threshold for depolarization
  • Alter conduction velocity in different parts of the heart
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where do most antiarrhythmic medications work (in which phase)?

A

At the effective refractory phase

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

What is the absolute (effective) refractory phase?

A
  • Phases 0,1,2 and most of 3 (to about -50mV)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the relative refractory period?

A
  • Middle of phase 3 to beginning of phase 4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What term is synonymous with absolute (effective) refractory period?

A

Depolarization

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

What are the 3 areas of the heart that have pacemaker activity?

A
  • SA node
  • AV node
  • Purkinje fibers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What drives automaticity?

A

Spontaneous opening and closing of K+ channels

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

What is important in determining how easily and how frequently cells can depolarize?

A

Threshold and resting membrane potentials

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

How does the effective refractory period (ERP) relate between packemaker area cells and mycocardial cells?

A

ERP in pacemaker areas is longer than myocardial cells

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

Different arrhythmias require that the ERP be _________ or _________?

A

Lengthened of Shortened

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

When are drugs used to induce an arrhythmia?

A
  • Ventricular arrhythmias due to AV node block
  • Temporary heart block until pacemaker insertion
    • Epinephrine
    • Isoproterenol - beta 1 and beta 2 agonist
    • Hypokalemic diuretics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the contraindications for antiarrhythmics?

A
  • Complete AV heart block
  • Congestive heart failure
  • Hypotension
  • Known hypersensitivity to the drug
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does the Class IA Antiarrhythmic drug’s mechanism of action?

A
  • Na+ channel blocker (medium)
  • Blocks conduction
  • Prolongs duration of AP
18
Q

What does the Class IB Antiarrhythmic drug’s mechanism of action?

A
  • Na+ channel blocker (fast)
  • Blocks conduction
  • Decreases ERP
  • Shortens the AP
19
Q

What does the Class IC Antiarrhythmic drug’s mechanism of action?

A
  • Na+ channel blocker (slow)
  • Blocks conduction
  • Little effect on ERP
  • Slows conduction without affecting AP
20
Q

What does the Class II Antiarrhythmic drug’s mechanism of action?

A
  • Beta Blocker
  • Decreases SA node automaticity
  • Reduces sympathetic activity
21
Q

What does the Class III Antiarrhythmic drug’s mechanism of action?

A
  • K+ channel blocker
  • Prolongs the AP
  • Prolongs phase 3 repolarization
22
Q

What does the Class IV Antiarrhythmic drug’s mechanism of action?

A
  • Ca+ channel blocker
  • Slows conduction velocity at AV node
  • Decreases firing rate of SA and AV nodes
23
Q

What are the 3 drugs classified as Class IA antiarrhythmics?

A
  • quinidine
  • procainamide (Pronestyl)
  • disopyramide (Norpace)
24
Q

What are some characteristics of quinidine?

A
  • Toxic - can produce fatal arrhythmias
  • Made from bark of cinchona tree –> cinchonism
  • Site of action: atrial tissues
25
Q

What are some characteristics of procainamide (Prnoestyl)?

A
  • Class IA
  • Derivative of the local anesthetic procaine
  • Reversible lupus-like syndrome in 25% of pts
26
Q

What are some characteristics of disopyramide (Norpace)?

A
  • Class IA
  • Causes peripheral vasoconstriction
  • Treats ventricular arrhythmias, alternative to quinine and procainamide
27
Q

What is the class IB drug of choice, used to treat ventricular arrhythmias?

A

Lidocaine (crossover drug)

28
Q

What are other Class IB drugs that are indicated for other agents?

A
  • Site Ventricles:
    • phenytoin (Dilantin) - anticonvulsant
      • Gingival hyperplasia
    • mexiletine (Mexitil) - suppression of PVCs
    • tocainide (Tonocard) - suppression of life-threatening ventricular arrhythmias
29
Q

What are the characteristics of flecainide (Tambocor) and propafenone (Rythmol)?

A
  • Class IC
  • Acts on ventricles
  • Approved only for use of refractory ventricular arrhythmias (life-threatening)
    • Causes arrhythmias because of profound effect on Na+ channels in healthy heart tissue – Safety conern **
30
Q

What class of antiarrhythmic drugs block effects of catecholamines on pacemaker cells to prolong the refractory period?

A

Class II

31
Q

What do Class II antiarrhythmic drugs do?

A
  • Depress automaticity
  • Prolong AV conduction
  • Decrease heart rate and contractility
32
Q

What do Class III antiarrhythmic drugs do?

A
  • Block K+ channels
  • Prolongs AP and prolongs effective refractory period (ERP)
  • Slows heart because drug reduces amount of norepinephrine released
33
Q

What are some characteristics of amiodarone (Cordaron, Pacerone)?

A
  • Class III
  • Life-threatening recurrent ventricular fibrillation
  • Contains iodine - blue skin
  • May cause thyroid disease
  • Severe toxic effects
34
Q

What are some characteristics of verapamil (Calan)?

A
  • Class IV
  • Dilates coronary and peripheral arteries
35
Q

What is the drug of choice for cardiac arrhythmias (PSVT)?

A

verapamil (Calan)

36
Q

What class IV antiarrhythmic medication is also called a cardiac glycoside?

A

Digoxin - used for treatment of congestive heart failure

37
Q

What does Digoxin do?

A
  • Inhibits Na/K ATPase pump
  • Increases intracellular Na/Ca exchange
  • Increases intracellular Ca leading to increased contractility
38
Q

What is used to treat bradyarrhythmias?

A
  • atropine (anticholinergic) - elevates sinus rate, accompany MI
  • isoproteronol (Isuprel) - beta agonist (beta1 and beta2), AV nodal block
39
Q

What is used to treat ectopic pacemakers?

A
  • Postassium
  • Magnesium ion
40
Q

What are the toxic reactions to antiarrhythmics?

A
  • Hypersensitivity
  • Hypotension, shock
  • Paradoxical arrhythmias
  • GI disorders
  • Cinchonism - quinidine

Pharmacology 2 (21 decks)

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