Antidysrhythmic Drugs

Question 1

What is the difference between Dysrhythmia and Arrhythmia?

Answer 1

Dysrhythmia - any deviation from normal rate/rhythm
Arrhythmia - no rhythm
Can be used interchangeably

Question 2

What is asystole?

Answer 2

No heartbeat

Question 3

What’s the difference between Tachydysrhythmias and Bradydysrhythmias?

Answer 3

Tachy is much more common. HR is increased and can be caused by drugs and other treatments

Brady is a slower HR, due to electrical pacing, can be impacted by drug Atropine

Question 4

What are 5 causes of dysrhythmias?

Answer 4

ischemic heart disease
myocardial infarction
cardiomyopathy
myocarditis
electrolyte imbalances

Question 5

What purpose does AP generation have?

Answer 5

AP leads to contraction in myocardial muscles

Question 6

What ion does the SA and AV node cells need to depolarize?

Answer 6

Ca2+

Question 7

What ion does Ventricula/Atrial muscle cells need to depolarize?

Answer 7

Na+

Question 8

What are 4 symptoms of dysrhythmias?

Answer 8

Palpitations
Dizziness
Fainting - when heart beats fast, there’s not enough time for it to fill. This reduces CO and blood won’t travel to head
Dyspnea

Question 9

Where does Supraventricular tachycardia originates, and what can it cause?

Answer 9

Origin of the dysrhythmia is in the atria
Beats 120-250

Can cause atrial flutter and atrial fibrillation.
The heart is beating very fast in the atrial flutter, and it is very unorganized and not even beating in fibrillation

Question 10

What can Ventricular Tachycardia cause?

Answer 10

Ventricular fibrillation
- Quivering ventricles. Blood is not effectively pumped to the rest of the body

More dangerous than atrial fibrillation

Question 11

When should you use a A-V block?

Answer 11

With Supraventricular dysrhythmias

Question 12

What are the classes of the Vaughan Williams Classification?

Answer 12

Class 1: Na channel blockers -
Class 2: B blockers
Class 3: K channel blockers 
Class 4: Calcium channel blockers
Other: adenosine, digoxin

Question 13

What is an example of a Class 1a blocker? When should you use it?

Answer 13

Quinidine

Used for acute onset of atrial fibrillation

• Wolff-Parkinson-White syndrome (usually tachy but can be slow with atrial fib/flutter)
• Slows atrial and ventricular rates

Question 14

What is an example of a Class 1b blocker? What is the only dysrhythmia it’s used for?

Answer 14

Lidocaine

Used for ventricular dysrhythmias only

Question 15

What is an example of a Class 2- B-adrenoceptor antagonist? What’s another name for this class?

Answer 15

Metoprolol

Reduces or blocks sympathetic nervous system (AV Block)

Question 16

What is an example of a Class 3 K blocker? What is used for and what are the long term side effects?

Answer 16

Amiodarone

Prolongs repolarization, extended refractory period of cells.

75% have serious adverse effects (lung fibrosis, thyroid)

Used for ventricular tachycardia or fibrillation, atrial fibrillation or flutter
- Resistant to other drugs

Question 17

What are 2 examples of a Class 4 calcium blocker? Which node does it act on? When should you use it?

Answer 17

Diltiazem, Verapamil

Mostly used for atrial problems, forms an AV block

Use for periodic attacks and not for ventricular dysrhythmias

Question 18

What are 2 unclassified Antidysrhythmics?

Answer 18

Digoxin, Adenosine

- both decrease AV conduction and SA automaticity

Question 19

What is the half-life of Adenosine? How is it administered and how does it function?

Answer 19

Slows conduction through the AV node
- AV block

Half life 20-30 seconds

Only administered as fast push IV

May cause asystole for a few seconds

Question 20

What is the major adverse effect of Antidysrhythmic drugs?

Answer 20

They can cause dysrhythmias!

Question 21

What are 5 symptoms the patient should be aware of?

Answer 21

SOB
Edema
Dizziness
Syncope
Drug toxicity

Question 22

When should you notify a physician with patients who are taking B-blockers or digoxin?

Answer 22

When the pulse (taken for 60 seconds radial) is less than 60 bpm