Anti-arrhythmia

Question 1

MOA for Class IA drugs (Quinidine, Procainamide)?

Answer 1

1˚ - Preferentially block open or activated Na channels; lengthen the duration of action potential
2˚ - Block K channels increase effective refractory period)

Question 2

MOA for Class IB drugs (lidocaine)?

Answer 2

Block inactivated sodium channels, shorten duration of action potential (decrease effective refractory period)

Question 3

MOA for Class IC drugs (Flecainide)?

Answer 3

Binds to all sodium channels, no effect on duration of action potential (no effect on effective refractory period)

Question 4

MOA for Class II drugs (B-blockers)?

Answer 4

Reduce adrenergic activity on the heart

Question 5

MOA for class III drugs (Amoidarone, sotalol)?

Answer 5

K+ channel inhibitors (increase effective refractory period)

Question 6

MOA for class IV drugs (Verapamil, diltiazem)

Answer 6

L-type Ca Channel blockers, decrease HR and contractility

Question 7

What broad spectrum drug is used to tx acute or chronic supraventricular or ventricular arrhythmias?

Answer 7

Quinidine

Question 8

What drug has a low therapeutic index can can easily cause:

1. Cardiac toxicity (SA/AV block, ventricular arrhythmia
2. Blocks alpha receptors –> sever HTN, reflex tachycardia
3. Paradoxical Tachycardia (reflex to vasodilation)
4. Tosades de pointes

Answer 8

Quinidine

Question 9

What drug causes widening of QRS, and QT intervals. This can lead to what?

Answer 9

Quinidine

Quinidine syncope

Question 10

Cinchonism and diarrhea are adverse effects of what drug?

Answer 10

Quinidine

Question 11

What drug can cause Lupus erythematous in slow slow acetylators: NAT2 gene?

Answer 11

Procainamide (class IA)

Question 12

What is DOC for ventricular arrhythmias?

Answer 12

IV Lidocaine (class IB)

Has least amount of negative inotropic effects, slows conduction

Question 13

Adverse effects of Lidocaine (2)

Answer 13

1. Bradycardia

2. Convulsions

Question 14

What drug is last ditch effort for supra-ventricular/life threatening ventricular arrhythmias, but ALSO can cause arrhythmias?

Answer 14

Flecainide (class IC)

Question 15

BB hack!

Answer 15

Drugs that start w/ A-M = B1 specific blockers
- Metoprolol, Esmolol
Drugs that start w/ N-Z = non-specific BB
- Propranolol

Question 16

What IV B1-blocker is 2nd line for Paroxysmal supraventricular tachycardia?

Answer 16

Esmolol (Class II)

Question 17

What is DOC for ventricular arrhythmias?

Answer 17

Amiodarone (Class III)

Also effective against both supreventricular arrhythmiass

Question 18

T or F: Amiodarone can cause torsades de pointes?

Answer 18

FALSE

No Torsades de pointes

Question 19

Pulmonary fibrosis, yellow-brown corneas, grey-blue skin and thyroid dysfunction are side effects of what drug?

Answer 19

AmIODarone

Increases IODine –> color changes and thyroid dysfunction

Question 20

What class III med blocks K+ but also is a non-selective B-blocker?

Answer 20

Sotalol

Question 21

What class III med is effective in treating ventricular and supraventricular arrhythmias BUT causes torsades de pointes?

Answer 21

Sotalol

Question 22

What drug is only effective in the atria but is used to tx reentrant SVT, PSVT and Afib/flutter

Answer 22

Verapamil and Diltiazem (class IV)

• Only effective in SVT b/c that is where Ca is important for rate

Question 23

Adverse effects of Verapamil and Diltiazem? (2)

Answer 23

1. Constipation

2. Avoid use w/ B-blocker –> Heart block

Question 24

Increased K conductance that hyperpolarizes and resets the heart is MOA for what drug?

Answer 24

Adenosine

Question 25

DOCs for acute PSVT (1-3 in order)

Answer 25

1. Adenosine 2. Esmolol 3. CCVs

Question 26

DOCs for chronic PSVT?

Answer 26

1. BB | 2. CCBs

Question 27

DOC for acute PSVT and WPW syndrome?

Answer 27

Adenosine

Question 28

What drug is has a t1/2 of 10 seconds and is effective only against reentry arrhythmias

Answer 28

Adenosine

Question 29

What is DOC for Torsades de pointes?

Answer 29

Magnesium (unknown MOA, IV only)

Question 30

What happens if you give pt w/ normal Mg levels Mg?

Answer 30

Anti-arrhythmic effect

Question 31

What medication is used in the management of seizures associated w/ severe toxemia or pregnancy (eclampsia)

Answer 31

Magnesium

Question 32

T or F: Hyperkalemia and hypokalemia are pro-arrhythmic?

Answer 32

TRUE

Question 33

T or F: Lidocaine, adenosine, and magnesium are IV only?

Answer 33

TRUE So used only in acute therapy

Question 34

What happens when you used anti-arrhythmic agents at high doses? (2)

Answer 34

1. Depress conduction in normal tissues | 2. Produce drug induced arrhythmias (potentially lethal)

Question 35

What is causes reentry arrhythmias?

Answer 35

Infarct blocks normal conduction pathway, the conduction then enters in retrograde direction, causing reentry of arrhythmia into circuit Others: obstacle to homogenous conduction or prolonged conduction time allows for more excitable tissues

Question 36

T or F: Any drug that is used to tx and arrhythmia can cause an arrhythmia?

Answer 36

TRUE