Arrhythmia 2 Flashcards by Corinne Perra

The hemodynamic effect of an arrhythmia depends on?

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

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A high HR will have what hemodynamic effect?

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

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A low HR will have what hemodynamic effect?

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

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What are clinical signs that result from low cardiac output?

Collapse or syncope 
Weakness 
Lethargy 
Tachypnea 
Hyporexia/vomiting

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

Restlessness
Excessive panting
Tachypnea/dyspnea

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When is anti-arrhythmic therapy indicated?

Arrhythmia is hemodynamically significant

Causing clinical sings

Potential to deteriorate into fatal arrhythmia

Negatively impacting cardiac function

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What are the types of anti-arrhythmic therapy?

Drugs

Electrical

cardioversion
defibrillation

Radio frequency ablation

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What is the MOA of class 1 anti-arrhythmics?

Block sodium channels

‘Membrane stabilizers”

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What is the MOA of class 2 anti-arrhythmics?

Primarily block B receptors

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What is the MOA of class 3 anti-arrhythmics?

Block potassium channels

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What is the MOA of class 4 anti-arrhythmics?

Primarily block calcium channels

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What are the class 1 drugs?

Lidocaine
Mexiletine
Procainamide
Quinidine

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What are the class 2 drugs?

Esomolol
Atenolol
Propranolol
Metoprolol

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What are the class 3 drugs?

Amiodarone

Sotalol

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What are the class 4 drugs?

Diltiazem

Verapamil

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What is the MOA of digoxin?

Increase vagal tone in the SA and AV nodes

What is the first choice drug for SVT?

Diltiazem

Secondary: B blocker, digoxin, sotalol

Can you give diltiazem orally in hemodynamically unstable patients?

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

IV takes effect in minutes

What are the treatments for A fib?

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

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

Rate control is not nessesary

Patient may benifit from cardioversion

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

True

-investigate underlying abuse

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

Diltiazem

When is treatment for a VPC indicated?

> 1000 single VPCs/24hr

Frequent or sustained ventricular bi- or trigeminity

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

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

True

-due to risk of ventricular fibrillation/sudden death

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

IV drug to stabilize Then transition to oral drug

What is the drug of choice for ventricular tachycardia?

Lidocaine (IV)

What secondary drugs can be used in VT treatment?

Procainamide Magnesium Amiodarone

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

Mexiletine or sotalol

What is an atropine response test used for?

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

What is a positive response to the atropine response test?

Sinus tachycardia, no pause, no AV block | —> Bradyarrhythmias is likely due to high vagal tone

What does a negative atropine response mean?

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

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

Usually no anti-arrhythmic therapy needed Look for underlying cause for high vagal tone

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

Requires pacemaker If pacemaker not an option —> oral therapy with parasympatholytic or sympathomimetic agents (eg hyoscyamine/theophylline) In emergency before pacemaker —> dopamine/dobutamine/iosprotrenol

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

False

When is treatment indicated for sick sinus syndrome?

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

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

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

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

Hyperkalemia

What is the treatment for primary atrial standstill ?

Pacemaker

What can cause artifacts of ECGs?

Electrical potentials that are non-cardia Patient/wire motion Electrical interference Poor contact between electrodes and patient Faulty ECG