Arrhythmias Flashcards

1
Q

What is the term for arrhythmias that are located above the ventricle, which origins of arrhythmia would be there?

A

Supraventricular arrhythmias (SA node, AV node, atria and His origin.

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2
Q

What is an ectopic beat?

A

It is a beat that has originated from somewhere other than the SA node.

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3
Q

What is triggered activity?

A

It is during phase 3 of cardiac myocytes where where there are afterdepolarizations that cause sustained depolarisations.

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4
Q

Factors that cause arrhythmias can lead to an increase in the slope of phase 4 in myocytes leading to an increased heart rate. This is caused by what?

A

Hyperthermia.
Hypercapnia.
Hypoxia.
Hyperkalemia.

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5
Q

What are some of the symptoms of arrhythmias?

A
Palpitations.
SOB.
Presyncope.
Syncope.
Heart failure.
Sudden cardiac death.
Angina.
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6
Q

What are some of the investigations you can do into arrhythmias?

A
ECG.
Electrocardiography (ECHO).
Exercise ECG.
Holors 24hr ECG.
CxR
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7
Q

Describe Sinus bradycardia?

A

HR <60 BPM
Regular rhythm.
Many athletes have.
Treat with atropine.

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8
Q

Describe sinus tachycardia?

A

HR >100 BPM
Treat underlying causes.
Maybe use beta blockers.

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9
Q

What are the three types of supraventricular tachycardia?

A

AV nodal reentrant tachycardia (AVNRT)
AV reciprocating tachycardia (AVRT).
Ectopic atrial tachycardia (EAT).

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10
Q

How do you treat an acute supraventricular tachycardia

A
You are trying to slow the HR and increase vagal tone.
II adenosine (potent vasodilator).
or verapamil (calcium channel antagonist) if adenosine not good enough.
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11
Q

How do you treat chronic supraventricular tachycardia

A

Antiarrhythmic drugs - digoxin.
B-blockers - bisoprolol.
RFCA - selective cutting of cardiac tissue to prevent tachycardia.

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12
Q

Describe 1st degree heart block?

A

It is not really heart block, the PR interval is just increased by >0.2 seconds, every P wave results in a QRS complex

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13
Q

Describe 2nd degree heart block - mobitz type 1?

A

It is intermittent block at the AV node, PR interval gets increasingly long to the point that a heart beat is missed, happens due to atrial impulses getting weaker and weaker to the point that they fail to stimulate ventricular contraction, cycle then repeats.

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14
Q

Describe 3rd degree heart block?

A

No action potentials from the SA node get to the AV node.

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15
Q

What are the four types of AF?

A

Permanent - not treatable.
Persistent - lasts for >48hrs.
Paroxysmal - lasts <48 hrs.
Lone (idiopathic) AF - no identifiable cause.

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16
Q

What rate controlling drugs should you use for AF?

A

Digoxin.
Verapamil - calcium channel antagonist.
B-blockers.

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17
Q

What rhythm controlling methods should you use for AF?

A

Amiodarone (anti-arrhythmic drugs).

Direct current cardioversion - shocking the patient.

18
Q

What would appear in the ECG of AF?

A

no p-waves.
Rapid QRS rhythm (>200 BPM).
HR irregularly irregular.

19
Q

What is atrial flutter?

A

It is caused by a re-entrant rhythm in either atrium.
There is a self-perpetuating loop due to an extra electrical pathway in the atrium.
Leads to very high HR.

20
Q

How would atrial flutter appear on an ECG?

A

Saw tooth appearance.

21
Q

What causes a supraventricular tachycardia?

A

The electrical signal re-enters the atrium, it then goes back through the AV node. This causes another ventricular contraction meaning that the HR is very fast.

22
Q

What would the QRS complex look like in a supraventricular tachycardia and the overall ECG?

A

It would be very narrow and last less than 0.12 seconds.

T wave, then immediately QRS complex then immediately T wave and so on.

23
Q

What will/won’t appear on an ECG in AF and why?

A

P waves won’t because atrial fibrillation is due to disorganised atrial electrical activity
Very narrow QRS complexes due to short contractions
An irregularly irregular rhythm.

24
Q

As there are irregular conductions in AF what happens to the ventricular contractions and what possible condition may occur as a side effect?

A

They become irregular irregular.
Tachycardic.
Heart failure due to poor filling of the ventricles.

25
Q

What are the most common causes of AF

A
AF affects Mrs SMITH
Sepsis
Mitral valve pathology (stenosis or regurgitation)
Ischaemic Heart disease
Thyrotoxicosis 
Hypertension
26
Q

Describe AV nodal reentrant tachycardia?

A

It is when the re-entry point is back through the AV node.

27
Q

Describe AV reentrant tachycardia?

A

It is when the reentrant pathway is an accessory pathway (Wolf-Parkinson White syndrome).

28
Q

Describe ectopic atrial tachycardia?

A

It is where the electrical signal originates somewhere other than the SA node.

29
Q

What is wolf-parkinson-white syndrome?

A

It is when conduction goes through the bundle of kent instead of the AV node, it is a type of AV reentrant tachycardia.

30
Q

What does wolf-parkinson-white syndrome look like on an ECG?

A

It has a short PR interval but a wide QRS complex.

31
Q

Describe mobitz type 2?

A

It is when for every P wave there is not always a QRS complex (maybe 3 p waves to 1 QRS complex).

32
Q

What is the first line treatment for AV block?

A

Atropine

33
Q

In complete heart block where does the electrical impulse come from and why?

A

Ventricles - No impulse gets from the SA node to the AV node so the ventricles take over.

34
Q

Why does complete (3rd degree) heart block have a regular rhythm?

A

Because even though the ventricles are not working with the atria any more, they are still giving regular impulses.

35
Q

What does adenosine act on, so which tachycardias does it act on?

A

It slows down the conduction in the AV node.

Supraventricular tachycardias.

36
Q

What are the QRS complexes like in AF?

A

Very narrow.

37
Q

Is there a risk of systemic embolism in AF?

A

Yes

38
Q

What should be the usual PR interval?

A

0.12-0.2 seconds (one box)

39
Q

What does the PR interval represent?

A

AV nodal delay.

40
Q

How long is the QRS complex usually?

A

Less than 0.12 seconds.

41
Q

When are the ventricles contracting?

A

QT interval, they are then relaxed during the TP interval.