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Flashcards in Antiarrhythmics 3 Deck (49)
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1

Effects of which class of drugs?

  1. Prolong the AP duration by reducing the outward (repolarizing) phase 3 potassium current 
  2. ***Main effect is to prolong the effective refractory period (ERP)
  3. Note - phase 4 diastolic potassium current (IK1) is not affected by these drugs.

class 3

2

Which drug's MOA:

  • Blocks IKr, INa, ICa-L channels,
  • β adrenoceptors

Amiodarone 

3

Effects of which drug?

  1. **Prolongs action potential duration and QT interval
  2. slows HR and AV node conduction
  3. low incidence of torsades de pointes

Amiodarone (class 3)

4

What are the clinical applications of Amiodarone (class 3)

1.** Serious ventricular Arrhythmias

2. **Supraventricular arrhythmias

 

 

5

What is the most commonly prescribed AAD?

Amiodarone (Class 3)

6

Pharmacokinetic of which drug?

  1. Oral, IV
  2. variable absorption and tissue accumulation
  3. hepatic metabolism, elimination complex and slow

Amiodarone (class 3)

7

Which drug has the following toxicities?

  1. Bradycardia and heart block in diseased heart,
  2. peripheral vasodilation
  3.  **pulmonary fibrosis
  4. hepatic toxicity
  5. **hyper- or hypothyroidism

Amiodarone (class 3)

8

Which drug has many interactions, based on CYP metabolism

Amiodarone (class 3)

9

The impressive effectiveness of ________ coupled with its low proarrhythmic potential has challenged the notion that selective ion channel blockade by AADs is preferable

Amiodarone 

10

What is the MOA of Dofetillide (class 3)?

IKr block

11

What are the 2 effects of Dofetillide (class 3)?

1. prolongs action potential

2. Prolongs effective refractory period

12

Clinical application of which med?

Maintenance or restoration of sinus rhythm in A-fib

Dofetillide (group 3)

13

PK of which drug?

Oral

• renal excretion

Dofetillide (class 3)

14

What is the toxicity of Dofetillide (class 3)?

***Torsades de pointes 

(initiate in hospital)

15

Interaction of which class 3 med?

Additive with other QT-prolonging drugs

Dofetillide

16

Which class 3 med is used for ventricular arrhythmias and A-fib?

Sotalol

17

Which class 3 med is used for conversion of atrial flutter and A-fib?

Ibutillide

18

Which class 3 drug reduces mortality in patients with A-fib?

Dronedarone

19

Which drug prolongs atrial refractoriness and is effective in A-fib

Vernakalant 

20

Effects of which class of drugs?)

•**Reduce inward calcium current during the AP and during phase 4 

•**Result= conduction velocity is slowed in the AV node and refractoriness is prolonged

•Pacemaker depolarization is slowed during this phase as well if caused by excessive calcium current. 

Class 4

21

Ca2+ channel blockers (L-Type) decrease excitability of SA nodal cells and prolong AV nodal conduction, primarily by slowing the ______ upstroke in nodal tissue.

 

actional potential

22

Which class of meds are useful in tx of arrhythmias that involve re-entry through the AV node

Class 4

23

High doses of Ca2+ channel blockers can prolong AV nodal conduction to such an extent that______ results

heart block

24

MOA of which 2 drugs?

  1. **Dependent ICa block slows conduction in AV node and pacemaker activity
  2. PR interval prolongation

Verapamil

Diltiazem

25

What is the clinical application of Verapamil?

**AV nodal arrhythmias, especially in prophylaxis

26

What is the clinical application of diltiazem (class 4-CCB)?

**Rate control in A-fib**

27

Which 2 meds have the following toxicities:

1. Cardiac depression

2. **Constipation

3. **Hypotension

Verapamil and diltiazem (class 4- CCB)

28

Which group of meds are calcium channel blockers but are not useful in arrhythmias; sometimes precipitate them

Dihydropyridines (group 4- CCBs)

29

MOA of which drug?

**interacts with Na+/K+-ATPase, K+, and Ca2+ channels**

(poorly understood)

Magnesium

30

which drug normalizes or increases plasma Mg?

Magnesium