CVS - Antiarrhythmic Drugs

Question 1

Depolarization is due to opening of which channels

Answer 1

Na+ channels

Question 1

Repolarization and Hyperpolarization is due to opening of which channels

Answer 1

K+ channels

Question 1

Phases of Action potential of Heart

Answer 1

Phase 0 - Depolarization (due to opening of Na+ channels)
Phase 1 - Repolarization (due to opening of K+ channels)
Phase 2 - Plateau phase (Both K+ And Ca2+ channels open)
Phase 3 - Only Potassium channel remains open

Question 1

Effect on AP graph after giving Na+ channel blockers

Answer 1

Decrease slope of Phase 0

Question 2

Effect on graph of AP after giving K+ channel blockers

Answer 2

Increase in APD (Action potential duration)

Question 2

Effect on graph of AP after giving K+ channel openers

Answer 2

Decreases APD

Question 2

Effect of K+ channel blockers on QT interval

Answer 2

Increases

Question 3

Classification of Antiarrhythmic drugs

Answer 3

Vaughan Williams Classification
Class i - Na+ Channel blockers
Class ii - Beta Blockers
Class iii - K+ Channel blockers
Class iv - CCB
Class v - Others

Question 3

Class i drugs can be classified into

Answer 3

Class ia - Na+ Blockers + K+ blockers
Class ib - Na+ blockers + K opener
Class ic - Na blockers, No effect on Potassium

Question 3

Effect of Class i drugs on AP

Answer 3

Slope of Phase 0 decreases
In ia - APD increases
In ib - APD decreases
In ic - No change in APD

Question 4

Class ia drugs

Answer 4

Quinidine
Procainamide

Question 5

Class ib drugs

Answer 5

Lignocaine
Phenytoin
Tocainide

Question 6

Class ic drugs

Answer 6

Encainide
Flecainide
Propafenone

Question 6

Class ii drugs or beta blockers can be used in which arrythmias

Answer 6

Atrial or ventricular tachyarrythmias

Question 6

Class iii or K+ channel blockers

Answer 6

B - Bretylium
I - Ibutilide
N -
D - Dofetilide
A - Amiodarone
S - Sotalol

Question 6

Bretylium uses

Answer 6

Was user for ventricular fibrillation earlier
Known as Pharmacological defibrillator

Question 6

Ibutilide and Dofetilide can be used in

Answer 6

Atrial fibrillation

Question 7

Which drug is Beta blocker and also blocks K+ channel

Answer 7

Sotalol

Question 8

Which is longest acting antiarrhythmic drug

Answer 8

Amiodarone - half life more than 3 weeks

Question 8

Amiodarone uses

Answer 8

Commonly used to prevent Arrythmias
Used as loading dose for acute arrythmia
Can be used for all arrythmias except QT prolongation

Question 9

Which antiarrhythmic drug have all 4 mechanism of action

Answer 9

Amiodarone

Question 10

Side effects of Amiodarone

Answer 10

The - can increase or decrease Thyroid
Peripheral of - Peripheral neuropathy
My - Myocardial depression
Lung - Lung fibrosis
Liver and - Hepatotoxic
Cornea is - Corneal deposits
Photosensitive - Photosensitivity (Blue man Syndrome)

Question 10

Drugs which can cause Pulmonary fibrosis

Answer 10

Bleomycin
Amiodarone
Methotrexate
Cyclophosphamide
Busulfan

Question 10

Class iv drugs or Calcium channel blockers

Answer 10

Verapamil - used in tachyarrythmias
Diltiazem
DHPs - not preferred in heart

Question 10

What happened if beta blockers and CCBs given simultaneously

Answer 10

Can cause Severe bradycardia

Question 10

Class v drugs

Answer 10

Digoxin
Atropine
Magnesium
Adenosine

Question 10

Digoxin can be used in which arrythmias

Answer 10

Atrial fibrillation associated with CHF

Question 10

Atropine is DOC in which arrythmias

Answer 10

Bradycardia and AV block

Question 11

Drug of choice for Long QT Syndrome (in TDP)

Answer 11

MAGNESIUM

Question 11

Which antiarrhythmic drug is shortest acting

Answer 11

Adenosine - half life less than 10 sec

Question 12

DOC in Peroxysmal Supraventricular Tachycardia (PSVT)

Answer 12

Adenosine