Arrhythmia 2

Question 1

The hemodynamic effect of an arrhythmia depends on?

Answer 1

Ventricular rate
Duration of abnormal rhythm
Inherent myocardial and valvular function
Temporal relationship between atria and ventricles (AV association)
Extra cardiac influences

Question 2

A high HR will have what hemodynamic effect?

Answer 2

Ventricles doesn’t have enough time to fill —> small stroke volume

Question 3

A low HR will have what hemodynamic effect?

Answer 3

Ventricles are not ejecting blood into arteries frequently enough to maintain BP and meet the body’s metabolic demands

Question 4

What are clinical signs that result from low cardiac output?

Answer 4

Collapse or syncope 
Weakness 
Lethargy 
Tachypnea 
Hyporexia/vomiting

Question 5

What clinical signs are due to anxiety and/or discomfort?

Answer 5

Restlessness
Excessive panting
Tachypnea/dyspnea

Question 6

When is anti-arrhythmic therapy indicated?

Answer 6

Arrhythmia is hemodynamically significant

Causing clinical sings

Potential to deteriorate into fatal arrhythmia

Negatively impacting cardiac function

Question 7

What are the types of anti-arrhythmic therapy?

Answer 7

Drugs

Electrical

• cardioversion
• defibrillation

Radio frequency ablation

Question 8

What is the MOA of class 1 anti-arrhythmics?

Answer 8

Block sodium channels

‘Membrane stabilizers”

Question 9

What is the MOA of class 2 anti-arrhythmics?

Answer 9

Primarily block B receptors

Question 10

What is the MOA of class 3 anti-arrhythmics?

Answer 10

Block potassium channels

Question 11

What is the MOA of class 4 anti-arrhythmics?

Answer 11

Primarily block calcium channels

Question 12

What are the class 1 drugs?

Answer 12

Lidocaine
Mexiletine
Procainamide
Quinidine

Question 13

What are the class 2 drugs?

Answer 13

Esomolol
Atenolol
Propranolol
Metoprolol

Question 14

What are the class 3 drugs?

Answer 14

Amiodarone

Sotalol

Question 15

What are the class 4 drugs?

Answer 15

Diltiazem

Verapamil

Question 16

What is the MOA of digoxin?

Answer 16

Increase vagal tone in the SA and AV nodes

Question 17

What is the first choice drug for SVT?

Answer 17

Diltiazem

Secondary: B blocker, digoxin, sotalol

Question 18

Can you give diltiazem orally in hemodynamically unstable patients?

Answer 18

No

Oral -takes effect in hours (only use in stable patient)

IV takes effect in minutes

Question 19

What are the treatments for A fib?

Answer 19

Rate control vs Rhythm control

Rate control (most common) 
-diltiazem -> slow conduction of AV node to reduce impulses reaching ventricles 

Rhythm control -electrical or pharmacologic cardioversion —> restores AV synchrony

Question 20

In some cases, A fib is not tachycardic. How would you treat this?

Answer 20

Rate control is not nessesary

Patient may benifit from cardioversion

Question 21

T/F: anti-arrhythmic therapy is not usually necessary for SVPC/ APCs

Answer 21

True

-investigate underlying abuse

Question 22

For a SPVC with frequent or sustained bigeminy what treatment could you use?

Answer 22

Diltiazem

Question 23

When is treatment for a VPC indicated?

Answer 23

> 1000 single VPCs/24hr

Frequent or sustained ventricular bi- or trigeminity

“R on T”—> VPC occurs on the Twave of another VPC

Question 24

T/F: any frequency or duration of ventricular tachycardia requires treatment

Answer 24

True

-due to risk of ventricular fibrillation/sudden death

Question 25

If a patient is hemodynamically unstable with VT, what type of drug should you use?

Answer 25

IV drug to stabilize

Then transition to oral drug

Question 26

What is the drug of choice for ventricular tachycardia?

Answer 26

Lidocaine (IV)

Question 27

What secondary drugs can be used in VT treatment?

Answer 27

Procainamide
Magnesium
Amiodarone

Question 28

If the VT is not sustained or frequent what drugs can you use to treat?

Answer 28

Mexiletine or sotalol

Question 29

What is an atropine response test used for?

Answer 29

Differentiate bradyarrhythmias caused by high vagal tone from those caused by structural heart disease

Question 30

What is a positive response to the atropine response test?

Answer 30

Sinus tachycardia, no pause, no AV block

—> Bradyarrhythmias is likely due to high vagal tone

Question 31

What does a negative atropine response mean?

Answer 31

No change in rate/rhythm or only mild change in bradyarrhythmia—> likely due to structural heart disease

Question 32

What is the best therapy for first degree AV block or a Mobitz type 1 second degree AVB?

Answer 32

Usually no anti-arrhythmic therapy needed

Look for underlying cause for high vagal tone

Question 33

High grade Mobitz type 2 and third degree AV blocks are treated how?

Answer 33

Requires pacemaker

If pacemaker not an option —> oral therapy with parasympatholytic or sympathomimetic agents (eg hyoscyamine/theophylline)

In emergency before pacemaker —> dopamine/dobutamine/iosprotrenol

Question 34

T/F: sick sinus syndrome is associated with high risk of sudden death

Answer 34

False

Question 35

When is treatment indicated for sick sinus syndrome?

Answer 35

Patient is symptomatic and if arrhythmia is resulting in cardiac remodeling/dysfunction

Question 36

What is the treatment for sick sinus syndrome, if required?

Answer 36

Pacemaker

• if cant do pacemaker—> parasympatholytic or sympathomomeic
• emergency prior to pacemaker—> doampine/dobutamine/isoproterenol (caution in patient with tachyarrythmias)

Question 37

What must you rule out for a cause of atrial standstill when considering treatment?

Answer 37

Hyperkalemia

Question 38

What is the treatment for primary atrial standstill ?

Answer 38

Pacemaker

Question 39

What can cause artifacts of ECGs?

Answer 39

Electrical potentials that are non-cardia

Patient/wire motion

Electrical interference

Poor contact between electrodes and patient

Faulty ECG