ECG Interpretation and Cardiac Arrhythmias Flashcards Preview

CLASP - Sudden Death > ECG Interpretation and Cardiac Arrhythmias > Flashcards

Flashcards in ECG Interpretation and Cardiac Arrhythmias Deck (32)
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What inherited cardiac conditions are most likely to cause sudden death?

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


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

- many patients never become symptomatic


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

- 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


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

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


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

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


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

- Adrenergic stimulation


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

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


Is Prolonged QT syndrome autosomal dominant or recessive?

Isolated Long QT = Dominant

Long QT and Deafness = Recessive


How is a diagnosis of Long QT made?

- 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


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

LQTS1 - Large and wide T wave

LQTS2 - Notch in middle of T wave

LQTS 3 - Very delayed T wave


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

- 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


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

- 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


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

- this does NOT increase a patients risk


What treatment could potentially be lifesaving in Brugada syndrome?

paracetamol - to reduce fever


What drugs should be avoided in Brugada syndrome?

- antiarrhythmics
- analgesics
- psychotropics


What triggers Catecholamine Polymorphic Ventricular Tachycardia syndrome (CPVT)?

- emotional tress
- physical activity


What is the characteristic ECG finding in CPVT?

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


How is CPVT treated?

- controlled by Beta Blockers
- ICDs usually also in place
- rarely treated with flecainide


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

- 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


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

Delta Wave


How is Wolff-Parkinson White Syndrome treated?

Cardiac ablation


What problems does hypertrophic cardiomyopathy cause?

- rhythm problems related to large muscle bulk
- Also obstruction may occur


HOw does hypertrophic cardiomyopathy usually present?

- sudden death
- heart failure (this may be end stage)


What should patients with hypertrophic cardiomyopathy avoid?

- competitive sport
- ICD implantation may be required depending on risk


Describe the problem in dilated cardiomyopathy

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


Describe what rhythm problem occurs in Arrhythmogenic RV Cardiomyopathy

Ventricular tachycardia which goes continually around the right ventricle


How is ARVC managed?

- ICD given to high risk patients
- Avoidance of competitive sport recommended


Where in the heart are ICDs placed?

- 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


What complications can arise from an ICD placement?

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

**ALSO high risk of death during ICD extraction**


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

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