Anti-arrhythmiatics

Question 1

Examples of Class Ia anti-arrhythmics?

Features?

Answer 1

Quinidine, Disopyramide, Procainamide.

Not great. Bizarre side effects. Do not prolong life. Pro-arrhythmic as they prolong the QT interval.

Question 2

Examples of class Ib anti-arrhythmics? 
Features?

Answer 2

Lignocaine (IV)

Standard treatment for ventricular arrhythmias a/w AMI and cardiac surgery. Rapidly metabolised. Acts well on ischaemic myocardium.
SE’s include drowsiness, parasthaesia, seizure activity. If plasma lvls are high.

Mexiletine (PO)

Treats ventricular arrhythmias.

Phenytoin

Treats seizure disorders.

Question 3

Examples of class Ic anti-arrhythmics? 
Features?

Answer 3

Flecanide (PO)

Only in life-threatening VT or SVT. Major SE is pro-arrhythmitic.

Propafenone (PO)

Only in life-threatening arrythimias. Major SE is proarrhytmic and exacerbation of lung disease.

Question 4

Examples of class II anti-arrhythmics? 
Features?

Answer 4

Atenolol, Propranolol (B blockers)
Targets SA node, AV node. Treats VA and SVT. SE’s include bronchoconstriction, Heart block, Heart failure.
Also treat angina.

Question 5

Examples of class III anti-arrhythmics? 
Features

Answer 5

Sotalol, Amioderone, Bretylium, Dronederone.

Question 6

Examples of Class IV anti-arrhythmatics?

Features?

Answer 6

Verapamil, Diltiazem.

Act on AV node. Treat SVT only. SE’s include CCF and interacts with B blockers.

Question 7

Function of Digitalis (Digoxin)?

Answer 7

Anti-arrhythmitic. 
Rate controlling agent. 
Increases central vagal activity. 
Slows conduction through AVN and BOH. 
Positive inotropic effect.