ECG interpretation and cardiac arrhythmias Flashcards

1
Q

what is sudden cardiac death

A

non-traumatic, non-violent, unexpected sudden cardiac arrest within 6 hours of previously witnessed normal health

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2
Q

what is a common manifestation of many genetic conditions

give examples

A

arrhythmias

  • inherited arrhythmia syndromes
  • inherited cardiomyopathies
  • inherited multi system disorder eg myotonic dystrophy
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3
Q

what are the 2 broad categorical causes of arrhythmias

A

channelopathies

cardiomyopathies

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4
Q

what is a channelopathy and give examples

A

rhythm problem

  • LQTS
  • Brugada
  • Catecholaminergic polymorphic VT (CPVT)
  • short QT syndrome
  • familial Wolf Parkinson White WPW
  • familial AF
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5
Q

what is a cardiomyopathy and give examples

A

structural disorder of the heart leading to abnormal rhythm formation

  • hypertrophic
  • restrictive
  • dilated
  • arrhythmogenic right ventricular cardiomyopathy ARVC
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6
Q

where is the normal pacemaker of the heart

A

SA node in the RA

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7
Q

what are ectopic pacemaker sites

A

sites outside the SA node that spontaneously depolarise

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8
Q

what are afterdepolarisations and when can they be seen

A

spontaneous depolarisations seen in a prolonged action potential
eg in LQTS

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9
Q

what are early afterdepolarisations

A

spontaneous depolarisation occurring in phase 2/3

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10
Q

what is a complications of early afterdepolarisations

A

Torsades de Pointes

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11
Q

hypo/hyperkalaemia can potentiate torsades de pointes

A

HYPOkalaemia

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12
Q

which drugs can potentiate torsades de pointes

A
any drug that increases QT interval - blocks K outflow in repolarisation:
anti-arrhythmics - class I + III
clarithromycin 
amiodarone 
fluoroquinolones
tricyclic antidepressants
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13
Q

what does a surface ECG measure

A

summation of all ion currents across the cell membrane

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14
Q

what is the basic pathology in LQTS

A

long QT interval leads to an extradepolarisation in a vulnerable part of the heart leading to an arrhythmia

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15
Q

how many are carriers of Congenital LQTS

A

1 in 2000

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16
Q

what can trigger polymorphic VT/Torsades in congenital LQTS

A

adrenergic stimulation

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17
Q

what is the QT interval

A

ventricular depolarisation and repolarisation

start of the Q wave to the end of the T wave

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18
Q

how can LQTS present

A

seizures
syncope
life threatening arrhythmias
sudden death

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19
Q

management of congenital LQTS

A

B blockers

ICD

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20
Q

what is Jervell and Lang-Nielsen syndrome

A

AR inherited form of LQTS

associated with congenital deafness (bilateral SNHL) and ventricular tachyarrhythmias

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21
Q

what is Romano Ward syndrome

A

AD inherited form of LQTS with ventricular tachyarrhythmias and NO deafness

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22
Q

what is a prolonged QTc (QT interval corrected for heart rate) in males and females

A

males >440ms

females >460ms

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23
Q

what is Andersen Tawil syndrome

A

AD inherited form of LQTS with extra cardiac features eg developmental abnormalities, periodic muscles weakness

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24
Q

What scoring system is used for diagnosis of LQTS

A

Schwartz score

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25
Q

what is LQTS

A

prolonged ventricular repolarisation leading to malignant ventricular arrhythmias

26
Q

what are metabolic/electrolyte causes of long QT

A
hypokalaemia 
hypomagnesaemia 
hypocalcaemia 
hypothermia 
myocardial ischaemia 
raised ICP
27
Q

what can cause a short QT

A

hypercalcaemia
short QT syndrome
digoxin

28
Q

what are some ECG signs of LQTS subtypes

A

giant T wave + long QT
extra notch in middle of T wave
far away T wave

29
Q

Conservative management of LQTS

A

avoid drugs that prolong Qt interval
correction of electrolyte abnormalities ASAP eg in vomiting, diarrhoea
avoid certain triggers eg strenuous swimming LQTS1, loud noises LQTS2

30
Q

what is short QT syndrome and how is it inherited

A

AD inheritance

very malignant, die in childhood, very high risk of arrhythmias

31
Q

what is Brugada syndrome and what is its inheritance

A

AD inheritance

Na channelopathy causing ventricular arrhythmias eg polymorphic VT or VF

32
Q

which arrhythmia is usually found in brugada syndrome

A

atrial fibrillation

33
Q

administration of which drugs leads to diagnostic changes on ECG in Brugada syndrome

A

Na channel blockers

34
Q

males/females are more affected by Brugada

A

males

35
Q

in Brugada syndrome, what are some triggers for VF

A

rest/sleeping
fever
excess alcohol
big meals

36
Q

in Brugada syndrome, FH influences prognosis, true or false

A

false, FH does not influence prognosis

37
Q

what should be given to patients with Brugada syndrome if they develop a fever

A

paracetamol ASAP

38
Q

management of Brugada syndrome

A

avoid certain medications
early paracetamol in fever
avoid excessive alcohol and large meals
ICD

39
Q

What is CPVT

A

Catecholaminergic polymorphic ventricular tachycardia

unusual and very difficult to treat

40
Q

what is there an abnormal response to in CPVT

A

adrenaline

41
Q

CPVT is easy/difficult to manage

what is the management

A

very difficult

high dose B blockers

42
Q

how can CPVT be inherited

A

AD - ryanodine receptor

AR - CASQ2

43
Q

what is a pathognomonic feature on ECG for CPVT

A

bidirectional VT

44
Q

what is Wolf Parkinson White syndrome WPW

A

accessory pathway in the heart which bypasses the AV node resulting in arrhythmias

45
Q

features of WPW

A

short PR interval
delta wave
ventricular pre excitation from accessory pathway
atrial fibrillation

46
Q

WPW investigation

A

treadmill to check if accessory pathway exists

diagnostic electrophysiological test

47
Q

management of WPW

A

ablate accessory pathway

48
Q

what is hypertrophic cardiomyopathy (HCM)

A

AD inherited - mutation in sarcomeric genes

very thick muscle in LV

49
Q

How can HCM present

A

sudden death
heart failure
atrial fibrillation

50
Q

management of HCM

A

control BP
HCM risk SCD calculator
ICD
avoid competitive sport

51
Q

what is dilated cardiomyopathy DCM

A

big, floppy, enlarged heart that doesnt work well

mutations in sacomeric and desosomal genes

52
Q

who is more affected by DCM

A

M>F

older age

53
Q

what is ARVC

A

arrhythmogenic right ventricular cardiomyopathy

fatty infiltration of cardiac myocytes in RV

54
Q

which arrythmia do you get in ARVC

A

re-entrant VT around the fat

55
Q

management of ARVC

A

avoid competitive sports
B blockers maximum dose
ICD

56
Q

what types of ICD exist

A

regular - sit within the heart, more invasive

subcutaneous - do not sit within the heart

57
Q

what is the function of an ICD

A

delivers shock to defibrillate or restart cardiac cells to full potential and allow the SA node to take over

58
Q

what are complications of ICDs

A
infection - endocarditis 
perforation 
haemothorax 
clots
breaking 
dislodgement 
may deliver shock unnecessarily which is painful
59
Q

what are characteristic ECG features of Brugada syndrome

A

RBBB in V1, 2, 3

ST elevation

60
Q

what are characteristic ECG features of HCM

A

inverted T waves all along the chest leads

61
Q

what are characteristic ECG features of ARVC

A

epsilon wave - odd late spikes in QRS complex

62
Q

list causes of drug induced long QT interval

ABCDE

A
antiArrhythmics - class I + III
antiBiotics - clarithromycin 
antiCychotics - haloperidol 
antiDepressants - tricyclics 
antiEmetics - ondansetron