Dysrrhthmia

Question 1

Anti arrhythmic drugs - modify the impulse generation and conduction to lrevent arrhythmia or reduce its symptoms

Answer 1

Vaughan Williams classification
Class 1 - Na channel blockers
Same 2 - beta blockers
Same 3 - k channel blockers
Same 4 - Ca channel blockers

Question 2

Class 1 - Na

Answer 2

MODERATE block of Na channel
MODERATE decrease odmf Na influx som moderately slow phase 0, excitability and conductivity
Correct slow phase 4 so LOW automaticity

Question 3

Group 1 A also
Block K channel so delay repolarisation and prolongs phase 3

Answer 3

Quinidine
Procainamide
Disopyramide
For:
AF and Ventricular tachycardia

Question 4

Group 1B, unlike broad spectrum group 1 have

Answer 4

Narrow spectrum:
Only in ventricular (and not supra) arrhythmia from MI or digitalis

Question 6

Group 1 B block mainly inactivated Na channel

Answer 6

Slows phase 4 so Slows automaticity
No effect on AVN so nit effective in AF

Question 7

Group 1 B

Answer 7

Lidocaine - IV (extensive first pass) so emergencies
Orally
Phenytoin
Mexiletine

Question 8

Uses of lidocaine

Answer 8

MI
General anaesthesia
Digitalis induced arrhythmia
Cardio surgery catheter

Question 9

Lidocaine not used in HB

Answer 9

As it doesn’t affect AVN

Question 10

Nystagmus

Answer 10

Lidocaine toxicity

Question 11

Plus drowsiness, slurred speech, agitation, convulsion and allergy

Answer 11

More lidocaine toxocity

Question 12

Phenytoin on the other hand

Answer 12

Can be given with HB as it increases AV conduction

Question 13

Group 1 C

Answer 13

Block activated Na so affects phase 0:
Slow phase with slow excitability and conductivity
With slow dissociation so Prolonged effect
Beta blocking effect

Question 14

Contraindicated jn csgructural heart diseases

Answer 14

Group 1 C
Because of pro arrhythimic beta blocking effect

Question 15

Group 1C
Also broad spectrum sp ventricular and supraventrucular tachycardia

Answer 15

Felecainide, encainide and propafenpne

Question 16

Class 2 - BB (broad spectrum from atrial flutter to the arrhythmias

Answer 16

Propranolol
Atenolol
Metoprolol - popular
Esmolol - used IV in emergencies because of ultrashort (10 minutes) half life

Question 17

For tachyarrhytmia due to sympathetic overactivity

Answer 17

Beta blocker

Question 18

Risk of bronchospasm in

Answer 18

Nonselective beta blockers
Reduced with metoprolol

Question 19

Class 3 - K blockers

Answer 19

Prolonged phase 3 and AP duration plus Refractory period

Question 20

Class 3 (broad spectrum as well so sever supra(AF) and ventricular tachycardia plus digitalis induced arrhythmia

Answer 20

Amiodarone
Drinedarone
Bretylium
Sotalol

Question 21

For figitalis induced arrhythmias

Answer 21

Lidocaine (inactive Na blocker)
K channel blockers

Question 22

AmIODarone

Answer 22

Blocks k so delays repolarisation affecting the phases of the WHOLE HEART

Question 23

Weak Na (both activated and inactivated)
With non competitive beta
And Ca channel blockers

Answer 23

i.e all class activity
Amiodarone
Also decreases AV and SAN

Question 24

Slow metabolism plus 25 - 60 days half life

Answer 24

Amiodarone

Question 25

Amiodarone use

Answer 25

Severe and refractory supraventricular and ventricular arrhythmias

Question 26

Corneal deposits - optic neuritis Paraesthesia Skin discolouration Thyroid dysfunction as 40 percent of its weight is iodine Pulmonary inflammation and fibrosis Proarrhythmic, bradycardia, heart block HF and hypertension

Answer 26

Amiodarone

Question 27

Dronedarone

Answer 27

Amiodarone derivative without iodine (no thyroid dysfunction), less side effects and shorter half life

Question 28

Class 4 - CCB (non dihydros)

Answer 28

Affects: SAN - excitability AVN - and conductivity Ectopic focus - automaticity

Question 29

Non dihydropyridines treat

Answer 29

Supraventricular tachycardia Atrial flutter and fibrillation- decrease the rate

Question 30

Unclassified drugs

Answer 30

Adenosine Dioxin Mg SO4 Ranolazine Ivabradine Potassium