Antiarrhythmics

Question 1

Class 1 antiarrhythmics block what channels? Result in what overall effect to the AP

Answer 1

Voltage gated sodium channels.

Prolongs the phase 0 upstroke and slows the cardiac AP.

Question 2

Do class 1 antiarrhythmics block open, closed, or inactivated Na+ channels?

Answer 2

Open or Inactivated

Question 3

What type of cardiac tissues do Class 1 antiarrhythmics have an effect on?

Answer 3

Rapidly depolarizing cells

Question 4

Class 1 antiarrhythmics have what effect on an ECG?

Answer 4

Increased QRS duration and prolonged AP

Question 5

Name the Class 1a antiarrhythmics

Answer 5

Quinidine
Procainamide
Disopyramide

Question 6

Binding affinity of Class 1a, b, and c?

Answer 6

a - Intermediate
b - Low
c - High

Question 7

Class 1a MOA?

Answer 7

Inhibit Na+ and K+ voltage gated channels. This slows down Phase 0, 2, and 3 and increases the refractory period.

Question 8

Class 1a treats?

Answer 8

Supraventricular and ventricular arrhythmias

WPW

Question 9

Class 1a adverse effects?

Answer 9

Cinchonism
Thrombocytopenia
Lupus like syndrome
Exacerbate HF
Precipitate torsades

Question 10

Name the class 1b medications?

Answer 10

Lidocaine
Mexiletine
Phenytoin

Question 11

Class 1b MOA?

Answer 11

Inhibit Na+ and moderately slow phase 0 upstroke. Decreased phase 2 and 3 leading to a decreased refractory period

Question 12

Class 1b treats?

Answer 12

Ventricular arrhythmias

Question 13

Class 1b adverse effects?

Answer 13

Neurological issues

Question 14

Name the class 1c medications

Answer 14

Flecainidine

Propafenone

Question 15

Class 1c MOA?

Answer 15

Inhibit Na+ channels strongly and prolong the phase 0 upstroke. There is NO effect on AP duration.

Question 16

Class 1c treats?

Answer 16

Supraventricular and ventricular arrhythmias

A-fib

Question 17

Class 1c contraindication?

Answer 17

Ischemic heart disease

Question 18

Name the class 2 antiarrhythmics

Answer 18

Beta-blockers

Question 19

Class 2 MOA?

Answer 19

Blocking sympathetic input to the SA and AV nodes. Decrease cAMP. Closure of Calcium channels. Overall prolongation of phase 4. Decreased AV conduction

Question 20

Class 2 treats?

Answer 20

Supraventricular arrhythmias

A-fib, flutter

Rate control

Question 21

Class 2 effects on the ECG?

Answer 21

Prolonged PR interval

Question 22

Class 3 MOA?

Answer 22

Block K+ channels and prolong phase 2 and 3. Prolonged refractory period

Question 23

What is special about Amiodarone?

Answer 23

Shares properties of class 1, 2, 3 and 4 antiarrhythmics

Question 24

Name the class 3 antiarrhythmics

Answer 24

Amiodarone
Dofetilide
Ibutilide
Sotalol

Question 25

Class 3 treats?

Answer 25

Supraventricular and ventricular arrhythmias

A-fib

Question 26

Amiodarone side-effects

Answer 26

Neurologic
Gray corneal deposits
Thyroid issues
Pulmonary fibrosis
Heart block
HF
Hepatitis
Skin discoloration
Photodermatitis
Inhibits CYP-450

Question 27

Can class 3 antiarrhythmics induce torsades?

Answer 27

YES

Question 28

What are class 4 antiarrhythmics?

Answer 28

NDHP CCBs

Question 29

Name the class 4 antiarrhythmics

Answer 29

Verapamil

Diltiazem

Question 30

Class 4 MOA

Answer 30

Block Calcium current in the SA and AV nodes. Prolong phase 4, decreased pacemaker, prolonged conduction and prolonged refractory period.

Prolonged PR interval

Question 31

NDHP treat?

Answer 31

Supraventricular arrhythmias
A-fib
Rate control

Question 32

NDHP adverse?

Answer 32

Cause heart block

Question 33

Digoxin MOA

Answer 33

Stimulation of the vagus nerve and AV nodal inhibition

Question 34

Digoxin treats?

Answer 34

Prevents rapid ventricular response in A-fib

Question 35

Magnesium treats?

Answer 35

Arrhythmias such as torsades

Question 36

Adenosine MOA

Answer 36

Activates inhibitory A1 receptors on the myocardium at the SA and AV nodes. Suppresses inward Ca++ current and increases outward current of K+. Overall decreased AV conduction and prolonged refractory period

Question 37

Adenosine treatment?

Answer 37

Acute supraventricular arrhythmias such as PSVT

Question 38

Adenosine effect on A2 receptors?

Answer 38

Coronary dilation

Question 39

Adenosine adverse effects?

Answer 39

Cutaneous flushing
SOB, chest pain, feeling of impending doom
Headache
Hypotension

Question 40

Adenosine effects are inhibited by?

Answer 40

Caffeine and Theophylline