Anti-arrhythmic Agents

Question 1

Class I Anti-arrhythmic Agent

Answer 1

Lidocaine: Blocks Na+ Channels

Indications: Management of acute ventricular arrhythmias during cardiac surgery or MI

Actions: Decreases depolarization, decreasing automaticity of the ventricular cells; increases ventricular fibrillation threshold.

Question 2

Lidocaine adverse effects:

Answer 2

Anaphylactoid reactions, hypotension, vasodilation, cardiac arrest

Don’t mix with digoxin, risk for arrhythmia increases.

Question 3

Class II Anti-arrhythmic Agent

Answer 3

Propanolol: Beta blockers

Indications: Treatment of…

1. Cardiac arrhythmias
2. Especially SVT
3. Treatment of ventricular tachycardia induced by digitalis or catecholamines.

Question 4

Propanolol Actions

Answer 4

1. Competitively blocks beta-adrenergic receptors in the heart and kidney, has a membrane-stabilizing effect, and decreases the influence of the sympathetic nervous system.

Don’t mix with insulin, hypoglycemia happens.

Question 5

Propanolol Adverse Effects

Answer 5

1. Decreased exercise intolerance
2. antinuclear antibody development
3. pulmonary edema
4. gastric pain
5. cerebrovascular accident
6. heart blocks

Question 6

Class III Anti-arrhythmic Agent

Answer 6

Amiodarone: K+

Treatment of life-threatening ventricular arrhythmias

Actions: Acts directly on hear muscle cells to prolong repolarization and the refractory period, increasing the threshold for V. Fib; also acts on peripheral smooth muscle to decrease peripheral resistance.

Question 7

Amiodarone adverse effects

Answer 7

Malaise 
Hepatoxicity 
Constipation
Corneal microdeposits 
Pulmonary toxicity 

DONT MIX WITH ANTIHISTAMINES, PHENOTHIAZINES OR ANTIDEPRESSANTS

Question 8

Class IV Anti-arrhythmic Agent

Answer 8

Diltiazem: Ca+ channel blockers

Indications: Treatment of…

1. Paraoxysmal SVT
2. A. Fib
3. Atrial flutter

Actions: Blocks movement of Ca across the cell membrane, depressing the generation of action potentials slowing conduction of AV node.

Question 9

Diltiazem adverse effects.

Answer 9

Peripheral edema
AV block
Asthenia (abnormal lack of energy)
Hepatic injury