ECG interpretation and cardiac arrhythmias Flashcards by Hiba Alhasso

what is sudden cardiac death

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

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what is a common manifestation of many genetic conditions

give examples

arrhythmias

inherited arrhythmia syndromes
inherited cardiomyopathies
inherited multi system disorder eg myotonic dystrophy

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what are the 2 broad categorical causes of arrhythmias

channelopathies

cardiomyopathies

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what is a channelopathy and give examples

rhythm problem

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

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what is a cardiomyopathy and give examples

structural disorder of the heart leading to abnormal rhythm formation

hypertrophic
restrictive
dilated
arrhythmogenic right ventricular cardiomyopathy ARVC

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where is the normal pacemaker of the heart

SA node in the RA

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what are ectopic pacemaker sites

sites outside the SA node that spontaneously depolarise

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what are afterdepolarisations and when can they be seen

spontaneous depolarisations seen in a prolonged action potential
eg in LQTS

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what are early afterdepolarisations

spontaneous depolarisation occurring in phase 2/3

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what is a complications of early afterdepolarisations

Torsades de Pointes

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hypo/hyperkalaemia can potentiate torsades de pointes

HYPOkalaemia

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which drugs can potentiate torsades de pointes

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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what does a surface ECG measure

summation of all ion currents across the cell membrane

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what is the basic pathology in LQTS

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

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how many are carriers of Congenital LQTS

1 in 2000

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what can trigger polymorphic VT/Torsades in congenital LQTS

adrenergic stimulation

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what is the QT interval

ventricular depolarisation and repolarisation

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

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how can LQTS present

seizures
syncope
life threatening arrhythmias
sudden death

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management of congenital LQTS

B blockers

ICD

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what is Jervell and Lang-Nielsen syndrome

AR inherited form of LQTS

associated with congenital deafness (bilateral SNHL) and ventricular tachyarrhythmias

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what is Romano Ward syndrome

AD inherited form of LQTS with ventricular tachyarrhythmias and NO deafness

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

males >440ms

females >460ms

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what is Andersen Tawil syndrome

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

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What scoring system is used for diagnosis of LQTS

Schwartz score

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what is LQTS

prolonged ventricular repolarisation leading to malignant ventricular arrhythmias

what are metabolic/electrolyte causes of long QT

``` hypokalaemia hypomagnesaemia hypocalcaemia hypothermia myocardial ischaemia raised ICP ```

what can cause a short QT

hypercalcaemia short QT syndrome digoxin

what are some ECG signs of LQTS subtypes

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

Conservative management of LQTS

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

what is short QT syndrome and how is it inherited

AD inheritance | very malignant, die in childhood, very high risk of arrhythmias

what is Brugada syndrome and what is its inheritance

AD inheritance | Na channelopathy causing ventricular arrhythmias eg polymorphic VT or VF

which arrhythmia is usually found in brugada syndrome

atrial fibrillation

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

Na channel blockers

males/females are more affected by Brugada

males

in Brugada syndrome, what are some triggers for VF

rest/sleeping fever excess alcohol big meals

in Brugada syndrome, FH influences prognosis, true or false

false, FH does not influence prognosis

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

paracetamol ASAP

management of Brugada syndrome

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

What is CPVT

Catecholaminergic polymorphic ventricular tachycardia | unusual and very difficult to treat

what is there an abnormal response to in CPVT

adrenaline

CPVT is easy/difficult to manage | what is the management

very difficult | high dose B blockers

how can CPVT be inherited

AD - ryanodine receptor | AR - CASQ2

what is a pathognomonic feature on ECG for CPVT

bidirectional VT

what is Wolf Parkinson White syndrome WPW

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

features of WPW

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

WPW investigation

treadmill to check if accessory pathway exists | diagnostic electrophysiological test

management of WPW

ablate accessory pathway

what is hypertrophic cardiomyopathy (HCM)

AD inherited - mutation in sarcomeric genes | very thick muscle in LV

How can HCM present

sudden death heart failure atrial fibrillation

management of HCM

control BP HCM risk SCD calculator ICD avoid competitive sport

what is dilated cardiomyopathy DCM

big, floppy, enlarged heart that doesnt work well | mutations in sacomeric and desosomal genes

who is more affected by DCM

M>F | older age

what is ARVC

arrhythmogenic right ventricular cardiomyopathy | fatty infiltration of cardiac myocytes in RV

which arrythmia do you get in ARVC

re-entrant VT around the fat

management of ARVC

avoid competitive sports B blockers maximum dose ICD

what types of ICD exist

regular - sit within the heart, more invasive | subcutaneous - do not sit within the heart

what is the function of an ICD

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

what are complications of ICDs

``` infection - endocarditis perforation haemothorax clots breaking dislodgement may deliver shock unnecessarily which is painful ```

what are characteristic ECG features of Brugada syndrome

RBBB in V1, 2, 3 | ST elevation

what are characteristic ECG features of HCM

inverted T waves all along the chest leads

what are characteristic ECG features of ARVC

epsilon wave - odd late spikes in QRS complex

list causes of drug induced long QT interval | ABCDE

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