3,4

Question 1

CLASS IA anti arrhythmic
Slow phase 0,4 and prolonged phase 3 ( prolong Action Potential)

-Quinidine

Answer 1

-Prolonged the refectory period you inhibit the efflux of K channel

1-common uses: atrial flutter & fibrillation

2- can be used for ventricular tachycardia

3- maintaining sinus rhythm after D.C. cardio version

1-Anticholinergic adverse effect

2-Hypotension

Question 2

CLASS IA anti arrhythmic
Slow phase 0,4 and prolonged phase 3 ( prolong Action Potential)

-Procainamide

Answer 2

Similar to Quinidine except : 
1- less toxic on the
heart 
2- there is No anticholinergic  
or α-blocking actions

1-more effective in ventricular than in atrial arrhythmias

1-reversible lupus
2- Hypotension
3- Torsades de pointes
4- Hallucination

Question 3

CLASS IB (reduce action potential duration)

-Lidocaine

Answer 3

Emergency ventricular arrhythmia:
1-Such as during surgery as local anesthetic
2- after acut myocardial infarction

( NOT USED ITH ATRIAL ARRHYTHMIA)

1- hypotension
2- paresthesia
3- in high dose convulsions

Question 4

CLASS IB (reduce action potential duration)

-Mexiletine

Answer 4

1-ventricular arrhythmia

2-digitalis-induced arrhythmias

Effective ORALLY

Question 5

CLASS IC (no effect on action potential duration)

• Flecainide

Answer 5

1-supraventricular arrhythmias

2- WPW

3- very effective in ventricular arrhythmias

1- high risk of proarrhythmia V.IMP
2- heart failure due to -ve inotropic effect
3- CNS

Question 6

Class II Drugs

β₁ Blockers → Reduce sympathetic effect → 1- ↔ S.A Node automaticity ( Bradycardia )

2- ↓ refractory period of A.V Node ( Slow conduction )

-Esmolol

Answer 6

Used mainly in Rapid control of ventricular rate in patients with atrial
fibrillation or flutter (Tachycardia)

Also 
1-WPW
2-thyrotoxicosis
3-Digitalis induced arrhythmias
4-Atrial arrhythmia

Question 7

Class II Drugs

β₁ Blockers → Reduce sympathetic effect → 1- ↔ S.A Node automaticity ( Bradycardia )

2- ↓ refractory period of A.V Node ( Slow conduction )

• Propranolol,
• Atenolol,
• metoprolol

Answer 7

Used mainly in patients who had myocardial infarction to reduce incidence of sudden death due to ventricular arrhythmias

Also 
1-WPW
2-thyrotoxicosis
3-Digitalis induced arrhythmias
4-Atrial arrhythmia

Question 8

Class III
K+ channel blocker
Prolongs Phase 3
prolong action potential duration and prolong refractory period by prolonging phase 3 repolarization (blocking K channels)

-Amiodarone

Answer 8

1- Extremely long t1/2 (13 - 103 DAYS)
2- metabolized to its major active metabolite N-desethylamiodarone by cytochrome P450
3-hepatic metabolism - Can cross placenta, and appear in breast milk

1-main use: serious resistant ventricular arrhythmias.
2- maintenance of sinus rhythm after D.C. cardio version (as quinidine)

ارجع للسلايد أحسن

Question 9

Class III Drugs

- Ibutilide
 (Pure class III, with no additional effects)

-QT interval prolongation (phase 3)

Answer 9

• acute conversion of Atrial flutter or fibrillation to normal sinus rhythm

ADRS
Torsades de pointes

Question 10

Class IV Drugs

• Verapamil
• Diltiazem

Main site of action in the S.A and A.V Node leads to → slowing conduction and prolong effective refractory period

Answer 10

• Effective in atrial arrhythmia
• Re-entry supraventricular
  arrhythmias (e.g. WPW) - Not effective in ventricular
  arrhythmia