ECG interpretation

Question 1

What categories can arrhythmogenic inherited cardiac conditions be grouped into?

Answer 1

Channelopathies and cardiomyopathies

Question 2

What does a channelopathy result in

Answer 2

Arrhythmogenesis related to ion current imbalance and development of early and late depolarisations

Question 3

What does cardiomyopathy result in?

Answer 3

Arrhythmogenesis related to scar/electrical barrier formation and subsequent entry

Question 4

List some channelopathies

Answer 4

• congenital long QT syndrome
• brugada syndrome
• catecholaminergic polymorphic ventricular tacycardia (CPVT)
• Short QT syndrome
• Progressive familial conduction disease
• Familial AF
• Familial WPW

Question 5

List some cardiomyopathies

Answer 5

• Hypertrophic cardiomyopathy
• Arrhythmogenic right ventricular cardiomyopathy (ARVC)
• Dilated cardiomyopathy

Question 6

What are after depolarisations?

Answer 6

Abnormal depolarisations of cardiac myocytes that interrupt phase 2, 3 or 4 of the cardiac AP

Question 7

When do early afterdepolarisations occur?

What causes them?

Answer 7

Occur with abnormal depolarisation during phase 2 or phase 3, and are caused by an increase in the frequency of abortive action potentials before normal repolarisation is completed

Question 8

Phase 2 may be interrupted due to augmented opening of _______ channels, while phase 3 interruptions are due to the opening of _______ channels

Answer 8

Phase 2 may be interrupted due to augmented opening of calcium channels, while phase 3 interruptions are due to the opening of sodium channels

Question 9

Early afterdepolarisations can result in…

Answer 9

Torsades des pointes

Question 10

Early after depolarisations can be potentiated by ____________ and drugs that prolong the QT interval including class __ and ___ antiarrhythmic

Answer 10

Early after depolarisations can be potentiated by hypokalaemia and drugs that prolong the QT interval including class Ia and III antiarrhythmic

Question 11

What is a side effect of clarithromycin?

Answer 11

Prolongation of the QT interval

Question 12

What is the treatment for long QT syndrome?

Answer 12

Beta blocker is protective in some

Others need a ICD

Question 13

Which LQTS is shown here?

What is the commonest trigger?

What is its penetrance?

Answer 13

LQTS1

Exercise

62%

Question 14

Which LQTS is shown here?

What is the commonest trigger?

What is its penetrance?

Answer 14

LQTS2

Emotional stress

75%

Question 15

Which LQTS is shown here?

What is the commonest trigger?

What is its penetrance?

Answer 15

LQTS3

Sleep

90%

Question 16

Which current is involved in each LQTS?

Answer 16

LQTS 1= K current (Iks)

LQTS 2= K current (Ikr)

LQTS 3= Na current

Question 17

What is the inheritance pattern of LQTS?

Answer 17

Autosomal dominant

• Isolated LQT= Romano Ward
• Extra-cardiac symptoms= Andersen and Timothy syndrome

Autosomal Recessive

• Jervell and Lange-Nielsen Syndrome= associated deafness

Question 18

What score is used to diagnose LQTS?

Answer 18

Schwartz score

Question 19

What should be avoided in LQTS1 and LQTS2?

Answer 19

LQTS1 = strenuous swimming

LQTS2= loud noises

Question 20

What is the risk of brugada syndrome?

Answer 20

Polymorphic VT, VF

Question 21

What is common in brugada syndrome?

Answer 21

Atrial fibrillation

Question 22

What ECG findings are common in brugada syndrome?

Answer 22

ST elevation and RBBB in V1-V3

Question 23

What may be needed to see brugada syndrome on ECG?

Answer 23

provocation with flecainide or ajmaline - block the cardiac sodium channel

Question 24

Which genes are associated with brugada syndrome?

Answer 24

• cardiac sodium challen (SCN5A)
• Calcium channel (CACN1Ac)

Question 25

Who is brugada syndrome common in?

Answer 25

Adults, 8 x commoner in males