Cardiac Drugs

Front 1

Vaughn Williams Classification System

Back 1

5 Classes of drugs broken down by the primary mechanism of its anti-arrhythmic effect

Front 2

Describe Class 1

Back 2

These drugs interfere with Sodium (Na+) channels.
Further broken down into 1a 1b and 1c

Front 3

How does Class 1a work

Back 3

Black fast Sodium (Na+) channels. Depress phase 0 which prolongs action potential duration by slowing conduction

Front 4

Name 2 Class 1a drugs

Back 4

Procainamide and Quinidine

Front 5

Procainamide: Dosage

Back 5

Adult dosage 20-30 mg/min IV infusion up to 17 mg/kg loading dose. pediatric 15mg/kg IV over 30 to 60 min

Front 6

Procainamide: Indication and Contraindication

Back 6

Use for v-fib and pulseless v-tach after lidocaine doesn't convert these rhythms to sinus rhythm.
Do not use in complete heart block or 2nd and 3rd degree heart block unassisted by pacemaker.

Front 7

Describe how Class 1B antidysrthymics work.
Give an example

Back 7

These drugs are sodium channel blockers that shorten action potential thereby reducing refractoriness. They decrease V max in partially depolarized cells with fast response action potentials.
Lidocaine

Front 8

Lidocaine: Dosage

Back 8

Adult 1 to 1.5 mg/kg IV Repeat every 3 to 5 minutes up to dose of 3 mg/kg
Pediatric 1 mg/kg IV every 3 to 5 minutes up to 3 mg/kg

Front 9

Lidocaine: Indication and COntrindication

Back 9

Use to convert V-fib and V-tach in cardiac arrest to sinus rhythm or to convert v-tach to a sinus rhythm.
Don't use for supra-ventricular dysrhythmias, severe sinus bradycardia, severe degrees of sino-atrial, atrioventricular, and intraventricular heart heart block.

Front 10

Describe how Class 1c antidysrhythmics work.
Give an example

Back 10

Markedly depress phase 0 depolarization. Decreases conductivity with minimal effect on action potential duration. Most potent Sodium (Na+) channel blockers.
Flecainide and Propafanone

Front 11

Describe how Class 2 antiarrhythmic drugs work

Back 11

AKA Beta Blockers
selectively blocking the effects of catecholamines at the β1-adrenergic receptors, thereby decreasing sympathetic activity on the heart. They decrease conduction through the AV node.

Front 12

Describe Beta1

Back 12

*increase heart rate.
*Cardiac contractile force
*Cardiac automaticity and conduction
*Renin release

Front 13

Describe Beta2

Back 13

*Vasodilation
*bronchodilation
*inhibition of contractions
*Tremors

Front 14

Class 2 antiarrhythmics do not affect what

Back 14

Conduction velocity because they do not effect sodium channels

Front 15

Beta1 receptors are attached to what

Back 15

attached to calcium channels. Remember calcium is essential for muscle contraction and is released from the sarcoplasmic reticulum by an action potential.