Heart failure (positive Inotropic Drugs) and antidysrhythmics

Question 1

What class is amiodarone? What does it do? What is it resistant to?

Answer 1

It is a class 3 potassium channel blocker
extends refractory period of cells
resistant to other drugs

Question 2

Adverse effects of digoxin?

Answer 2

1.)Narrow theraputic window for digosin
-Drug levels must be monitored

2.) Low potassium levels increase toxicity

3.) GI (early adverse effects sign of dig toxicity)
-Anorexia, nausea, vomiting, diarrhea

4.) Colored vision (classic sign) (seeing yellow, green, purple, halo vision, flickering lights

Question 3

Movement of ions across the cardiac cell membrane results in? What does it lead to?

Answer 3

Movement of ions across the cardiac cell membrane results in AP generation
AP leads to contraction of the myocardial muscle

Question 4

Dysthrithmia Vs Arrhythmia?

Answer 4

Dysthrithmia: Any deviation from the normal rate/rhythm of the heart

Arrhythmia “no rhythm”

Question 5

Example of a class 1b anti-dysthymic drug that is used for ventricular dysrhythmias only?

Answer 5

Lidocaine (blocks Na+ channels)

Question 6

Example of Class II: b-adrenoceptor antagonists (beta blockers) ? What does it do?

Answer 6

-Metoprolol, esmolol (IV), propranolol, sotalol (also Class III)

Reduce or block sympathetic nervous system stimulation
AV Block

Question 7

What is Ventricular Tachycardia (VT) ?

Answer 7

problem with ventricular muscle
eg non-sustained (<30 sec) and sustained (>30 sec)

Question 8

Client care implications of digoxin?

Answer 8

Assess clinical parameters, including:
-Apical pulse (NOT radial) for 1 full minute
-Serum labs: potassium, sodium, magnesium, calcium, renal and liver function studies

Question 9

What is flecainide, encainide, propafenone? What do they block?

Answer 9

It is a class 1c CCB that blocks Na+ channels

Question 10

WHat does AP depend on?

Answer 10

AP depends on Ca2+ influx

Question 11

What does digoxin do?

Answer 11

AV block
Slows HR

Question 12

(Potassium Channel Blocker) -amiodarone, What is it used for?

Answer 12

-amiodarone

Used for Ventricular tachycardia or fibrillation, atrial fibrillation or flutter

Question 13

What factors increase the risk of digoxin toxicity?

Answer 13

-Low K+ (loop diuretics)
-Lead to hypokalemia then to toxicity
amphotericin B, furosemide, thiazides, laxatives, steroids

Question 14

What are Antidysrhythmics? What do most of them do?

Answer 14

-drugs used for the treatment and prevention of disturbances in cardiac rate and/or rhythm

-most suppress abnormal electrical impulse formation or conduction

Question 15

Antidysrhythmic Drugs - Vaughan Williams Classification

Answer 15

Class I – Na channel blockers
Class Ia
Class Ib
Class Ic
Class II – b blockers
Class III – K channel blockers (+ others)
Class IV - Calcium channel blockers
Other (adenosine, digoxin)

Question 16

What does diltiazem, verapamil act on? What do they do? What are they used for

Answer 16

Act on AV node – reduce conduction velocity
AV Block
Used for paroxysmal (“periodic attack”) SVT

Question 17

What does Digoxin and adenosine do?

Answer 17

Both decrease AV conduction and SA automaticity

Question 18

Antidote to Digoxin toxicity?

Answer 18

Digoxin immune fab
-This is employed during life threating cardiac dythrmthmina issues

Question 19

What is diltiazem, verapamil? What class is it apart of? What do they do? WhatWhat are they not used for?

Answer 19

Class IV: Calcium Channel Blockers
Inhibits Ca cell entry
Not for ventricular dysrhythmias

Question 20

Adverse effects of digoxin on the cardiovascular system?
What must we take? minium BPM?

Answer 20

-Dysrhythmias - including bradycardia
-Must take apical pulse

-Min 60 BPM
-If lower hold back dose

Question 21

WHat do class 2 B-adrenergic recepters increase? What do they reduce?

Answer 21

increase Ca influx
B-blockers reduce cell activity

Question 22

What is quinidine, procainamide, disopyramide? What are they used for?

Answer 22

It is a class 1a CCB that Block sodium channels
Slows atrial and ventricular rates

Used for ACUTE onset atrial fibrillation

Question 23

What are the 3 Ss of Digoxin?

Answer 23

1.) Strengthens
-Positive inotropic effect-
-Increase in force of myocardial contraction

2.) Slows
-Negative chronotropic effect-
-Reduce heart rate at SA node

3.) Slows
-Negative dromotropic effect
-Decreases AV nodal conduction and other effects

Question 24

What factors increase the risk of digoxin toxicity?

Answer 24

-Low K+ (loop diuretics)
-Lead to hypokalemia then to toxicity
amphotericin B, furosemide, thiazides, laxatives, steroids

Question 25

What is Supraventricular tachycardia?

Answer 25

Supraventricular tachycardia (SVT 120-250 beats/min)

Question 26

When is Digoxin used? Indications of use?

Answer 26

-Heart failure

*Supraventricular dysrhythmias – problem is above the ventricle
Atrial fibrillation and atrial flutter

Question 27

What can ALL antidysrhythmics can cause?

Answer 27

dysrhythmias!

Question 28

Digoxin Effects?

Answer 28

1.) Increases stroke volume (therefore cardiac output)
2.) Decrease in venous BP and vein engorgement
3.) Increase coronary circulation
*4.) Promotion of diuresis due to improved kidney perfusion
5.) Palliation of external, paroxysmal and nocturnal dyspnea, cough and cyanosis

Question 29

Example of Cardiac glycosides?

Answer 29

Digoxin

Question 30

Class I: Na Channel Blockers? What do they do?

Answer 30

block Na channels
slow depolarization

Question 31

What does Adenosine do? What kind of half-life does it have? How is it administered? What might it cause for a moment?

Answer 31

Slows conduction through the AV node
AV block

-Only administered as a FAST iv push

May cause asystole for a few seconds