Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Pharmacology > Dysrhythmia > Flashcards

Dysrhythmia Flashcards

0
Q

Which site in the heart is known as the pacemaker?

A

Sinoatrial node

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

Which classes of drugs are frontline agents for dysrhythmia?

A

Calcium channel blockers
Sodium channel blockers
Potassium channel blockers
Some Beta-blockers

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

In an ECG, what does the P-wave represent?

A

Atrial depolarization

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

In an ECG, what does the QRS complex represent?

A

Ventricle depolarization

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

In an ECG, what does the T wave represent?

A

Ventricle repolarization

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

In an ECG, what does the QT interval represent?

A

Duration of time between depolarization and repolarization of the ventricles.

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

What does Sotalol do to QT interval?

A

Lengthens it

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

How does Sinoatrial cardiac tissue spontaneously depolarize?

A

Positive slope during phase 4- tissue eventually gets to threshold potential for depolarization on its own.
The AV node also has a positive slope during phase 4, just not as positive as SA node, so SA node reaches threshold first.

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

What determines conduction velocity in cardiac tissues?

A

The number of functional sodium channels.

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

25% of patients taking ________ ____________ experience dysrhythmia (tachycardia).

A

Cardiac glycosides

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

In a cardiac action potential, what happens at phase 0?

A

Sodium ion channels open- rapid depolarization

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

In a cardiac action potential, what happens at phase 1?

A

Sodium ion channels close and Potassium ion channels open then close soon after.

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

In a cardiac action potential, what happens during phase 2?

A

Opening and closing of the Calcium channel. Some potassium leakage. “Plateau phase”.

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

In a cardiac action potential, what happens during phase 3?

A

Opening and closing of the Potassium channel. “Repolarization phase”.

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

In a cardiac action potential, what happens during phase 4?

A

Leakage that leads to spontaneous depolarization.

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

What are the three general ways in which dysrhythmias are discouraged?

A
  • Alter automaticity
  • Alter conduction velocity
  • Alter the refractory period
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

In what ways can automaticity be altered?

A
  • Decrease slope of phase 4 depolarization
  • Increase the threshold for action potentials
  • Decrease the resting membrane potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

In what ways can conduction velocity be decreased?

A
  • Decrease phase 0 slope
  • Decrease phase 4 slope
  • Decrease resting membrane potential and responsiveness
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

In what ways can refractory period be altered?

A
  • Prolong phase 2 plateau
  • Prolong phase 3 repolarization
  • Increase action potential duration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Drugs of Vaughan-Williams Class IA have what effect?

A

Moderate Na channel block, lowers conduction velocity by decreasing phase 0 slope.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Drugs of Vaughan-Williams class IB have what effect?

A

Minimal block of Na channels. Phase 0 slope decreased, conduction velocity slowed some. Phase 3 repolarization shortened. Net effect decrease in action potential duration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Drugs of Vaughan-Williams class IC have what effect?

A

Marked blockage of Na channels, slow conduction velocity, though there is no change in action potential duration or repolarization (QT interval).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the IA prototypes?

A
  • Quinidine

- Procainamide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the class IB prototypes?

A
  • Lidocaine

- Phenytoin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
What is the class IC prototype agent?
Flecainide
25
Drugs of Vaughan-Williams class II have what effect?
As beta blockers, they suppress sympathetic input. Phase 4 slope is decreased and conduction velocity is decreased. There is no effect on action potential duration.
26
Drugs of Vaughan-Williams class III have what effect?
These potassium channel blockers prolong the phase 3 repolarization. This lengthens QT interval.
27
What are the prototype class III agents?
Amiodarone | Ibutilide
28
Drugs of Vaughan-Williams Class IV have what effect?
Calcium Channel Blockers Decrease conduction velocity, increase effective refractory period, increase action potential duration. They have the greatest effect in tissues that are more calcium sensitive, like the SA and AV nodes.
29
What are the Class IV prototype drugs?
Verapamil | Diltiazem
30
Vaughan-Williams Classification is based on the action of drugs in ___________ tissue.
normal, healthy
31
Although Amiodarone is a Class III drug, it exhibits actions of all other V-W classes of drugs. Which additional actions does it exhibit?
- Sodium Channel blockade - Noncompetetive alpha & beta adrenergic inhibition - Calcium Channel blockade
32
Beta blockers and Calcium channel blockers are used for ______________ and not for _____________.
- supraventricular tachycardias | - ventricular tachycardias
33
Ca channel blockers are selective for ______ and __________ where Ca AP's predominate.
SA and AV nodes
34
What are the cardiac actions of Quinidine?
Decreased conduction velocity. Moderate Na channel block. Prolonged refractory period. Increased APD. Some K+ channel block- leads to prolonged repolarization. EFFECTS MORE PRONOUNCED IN DEPOLARIZED, DAMAGED TISSUE
35
What are the potential extracardiac effects of Quinidone?
- alpha adrenoreceptor blockage -> vasodilation - anti-muscarinic action -> accelerates heart - at certain concentrations, QT interval too lengthened. "Torsades de Pointes" arrhythmia - GI irritation - Headaches, dizziness, tinnitus
36
For which forms of arrhythmia is Quinidine effective?
Effective for both ventricular and supraventricular
37
What are the cardiac effects of Procainamide?
Class IA Decreased conduction velocity. Moderate Na channel block. Prolonged refractory period. Increased APD. Some K+ channel block- leads to prolonged repolarization. EFFECTS MORE PRONOUNCED IN DEPOLARIZED, DAMAGED TISSUE
38
What toxicity does procainamide have?
Cardiac: some cardiac depression | Non-cardiac: Syndrome that resembles lupus erythematosus
39
What is procainamide predominately used for?
Acute ventricular tachycardia
40
What is N-acetylprocainamide (NAPA)?
A liver metabolite of Procainamide that has some Class III activity
41
What are the cardiac effects of Lidocaine?
Class IB | Mild Na channel blocker. Shortens refractory period. Decreases action potential duration.
42
What kind of dysrhythmia is Lidocaine used to treat?
Acute Ventricular Tachycardia
43
What are the cardiac effects of Phenytoin?
Class IB | Shortens action potential duration
44
How is Phenytoin best used?
Taken orally, for chronic supraventricular and ventricular tachycardia.
45
What are some common extracardiac effects/uses of Phenytoin?
Anti-convulsant against epilepsy | Causes gingival hyperplasia
46
What are the cardiac effects of Flecainide?
Class IC Decreases slope of phase 0 Decreases conduction velocity No major change in APD
47
Which beta blockers have membrane stabilizing propterties, and what does that mean?
metoprolol, propranolol In addition to Class II properties, they function as Na+ channel blockers, decrease slope of phase 0, thereby further reducing conduction velocity.
48
Which beta blockers are commonly used to treat arrhythmias?
Esmolol, Metoprolol, Propranolol, Sotalol | Esmolol used only for arrhythmias. Sotalol also has Class III action
49
What is the half-life of esmolol, and what does that suit it for?
10 minutes | This makes it suitable for use during surgery when there is risk for arrhythmia.
50
Potential adverse effects of Amiodarone:
``` Torsades de Pointes Thyroid dysfunction Pulmonary fibrosis Photosensitivity Corneal microdeposits ```
51
Donedarone
Similar in action to Amiodarone, but with shorter (~24 hr) half-life. Does not have thyroid or pulmonary fibrosis issues like Amiodarone.
52
This intravenous Class III compound simply prolongs action potentials, has the lowest risk of causing Torsades de Pointes, and treats flutter better than fibrillation.
Ibutilide
53
Calcium channel blockers commonly used to treat Arrhythmias
Verapamil | Diltiazem
54
Which "Other" dysrhythmic is very short acting (15 seconds) and used for acute supraventricular tachycardias? What side effects does it have?
Adenosine | Flushing, hypotension
55
This cardiac glycoside decreases conduction in the AV node by stimulating the vagus nerve. Used mostly in chronic atrial fibrillation.
Digoxin
56
Which Vaughan-Williams class of drug would shorten action potential duration and have minimal effect on the Na+ channel?
Class IB
57
What is the half-life of Esmolol?
about 9 minutes
58
What is the half-life of Amiodarone?
25 to 100 days
59
What kinds of drugs would be suitable for treating ACUTE SUPRAVENTRICULAR tachycardias?
Adenosine Digoxin Calcium Channel Blockers
60
What kinds of drugs would be suitable for treating CHRONIC SUPRAVENTRICULAR tachycardias?
Beta Blockers | Calcium Channel Blockers
61
What drugs would be top choices for treating ACUTE VENTRICULAR tachycardias?
``` Amiodarone Procainamide Sotalol Bretylium Lidocaine ```
62
What drugs would be top choices for treating CHRONIC VENTRICULAR tachycardias?
Amiodarone Sotalol Flecainide

Pharmacology (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions