ECG Interpretation and Cardiac Arrhythmias Flashcards

1
Q

What inherited cardiac conditions are most likely to cause sudden death?

A
Inherited channelopathies/ arrhythmias
Inherited cardiomyopathies (structural problem)
Inherited Multi-System Disease causing cardiac involvement (e.g. Myotonic dystrophy)
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2
Q

Most patients are entirely fit and healthy until an event which causes sudden death. TRUE/FALSE?

A

TRUE

- many patients never become symptomatic

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3
Q

Why does Long QT syndrome (and otherr channelopathies) put patients at a higher risk of sudden death?

A
  • Ventricular repolarisation takes longer than normal
  • Early after-depolarisations or ectopic beats at vulnerable points of the cardiac cycle can cause Torsades de Pointes
  • This cardiac rhythm is very inefficient and cannot be sustained, resulting in sudden death
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4
Q

Give an example of a QT prolonging drug and why these can potentially cause harm?

A
  • Clarithromycin
  • If given to patient with an ALREADY undiagnosed prolonged QT syndrome, this drug puts them at a much higher risk of sudden death
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5
Q

What other channelopathies can put patients at a higher risk of sudden death and how are these identified?

A

Brugada syndrome - ST elevation and RBBB in V1-3

Short QT - usually diagnosed in young children who often experience sudden death in childhood

Catecholamine Polymorphic Ventricular Tachycradia (CPVT) - arrhythmias triggered by adrenergic stimulation => patient goes into VT

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6
Q

What triggers patients with congenital long QT syndrome to go into Torsades de Pointes?

A
  • Adrenergic stimulation
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7
Q

What is the mainstay of treatment for most patients with prolonged QT syndrome?

A

Beta blockers

- some may have an ICD but this is more common in other conditions as risk of sudden death is lower in Long QT

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8
Q

Is Prolonged QT syndrome autosomal dominant or recessive?

A

Isolated Long QT = Dominant

Long QT and Deafness = Recessive

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9
Q

How is a diagnosis of Long QT made?

A
  • usually by specialists in an MDT meeting
  • QT interval of >480ms on repeated ECGs = suggestive
  • If risk score calculated and >3, this is also suggestive
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10
Q

What ECG differences are present in the different variations of Prolonged QT syndrome?

A

LQTS1 - Large and wide T wave

LQTS2 - Notch in middle of T wave

LQTS 3 - Very delayed T wave

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11
Q

What advice should be given to both doctors and patients when managing those who have been diagnosed with prolonged QT syndrome?

A
  • Avoid QT prolonging drugs
  • Correct electrolyte disturbances (e.g. during vomiting/diarrhoea)
  • Avoid strenuous exertion in LQTS1 - e.g. swimming
  • Avoid very loud noises in LQTS2
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12
Q

What ECG changes occur in Brugada Syndrome, and when are these more likely to appear?

A
  • ST elevation and Right Bundle Branch Block in leads V1-3
  • These signs are intermittent on ECGs
  • Occurs more frequently when patient is feverish

Other factors which may increase risk are:
=> when resting/sleeping
=> Alcohol/large meals

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13
Q

Patients with family members who have experienced sudden death due to brugada syndrome are therefore at increased risk of sudden death themselves. TRUE/FALSE?

A

FALSE

- this does NOT increase a patients risk

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14
Q

What treatment could potentially be lifesaving in Brugada syndrome?

A

paracetamol - to reduce fever

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15
Q

What drugs should be avoided in Brugada syndrome?

A
  • antiarrhythmics
  • analgesics
  • psychotropics
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16
Q

What triggers Catecholamine Polymorphic Ventricular Tachycardia syndrome (CPVT)?

A
  • emotional tress

- physical activity

17
Q

What is the characteristic ECG finding in CPVT?

A

Bidirectional VT => some QRS complexes go upwards and some go downwards

18
Q

How is CPVT treated?

A
  • controlled by Beta Blockers
  • ICDs usually also in place
  • rarely treated with flecainide
19
Q

Describe how unwanted arrhythmias can be produced in Wolff-Parkinson White syndrome?

A
  • accessory pathway stops conduction delay in AV node

=> arrhythmias in the atria (Which would usually cease at the AV Node) can be passed to the ventricles

20
Q

What abnormal finding is found on an ECG of Wolff-Parkinson White?

A

Delta Wave

21
Q

How is Wolff-Parkinson White Syndrome treated?

A

Cardiac ablation

22
Q

What problems does hypertrophic cardiomyopathy cause?

A
  • rhythm problems related to large muscle bulk

- Also obstruction may occur

23
Q

HOw does hypertrophic cardiomyopathy usually present?

A
  • sudden death

- heart failure (this may be end stage)

24
Q

What should patients with hypertrophic cardiomyopathy avoid?

A
  • competitive sport

- ICD implantation may be required depending on risk

25
Q

Describe the problem in dilated cardiomyopathy

A

Problem within the proteins holding the cardiac myocytes together
=> the heart dilates and pulls apart
=> heart muscle cant pump well
=> this leads to rhythm problems

26
Q

Describe what rhythm problem occurs in Arrhythmogenic RV Cardiomyopathy

A

Ventricular tachycardia which goes continually around the right ventricle

27
Q

How is ARVC managed?

A
  • ICD given to high risk patients

- Avoidance of competitive sport recommended

28
Q

Where in the heart are ICDs placed?

A
  • 1 wire in the RA
  • 1 wire in the RV
    (device usually sits under left clavicle)

NEW devices can be inserted s/c on the breast bone

29
Q

What complications can arise from an ICD placement?

A
  • infection
  • clots (can break off and cause stroke or PE)
  • haemothorax
  • Pneumothorax

ALSO high risk of death during ICD extraction

30
Q

HOw long should the QT interval roughly be on an ECG?

A

QT interval should complete before the halfway point between two QRS complexes

31
Q

What condition can cause inverted T waves?

A

hypertrophic cardiomyopathy OR other structural abnormalities

32
Q

What Extra wave is seen on the ECG of Arrhythmogenic RV cardiomyopathy?

A

Epsilon wave

- “blip” straight after QRS complex