ECG Flashcards
Causes of non-ischaemic sudden cardiac death:
Hypertrophic cardiomyopathy
Arrythmogenic RV cardiomyopathy
Brugarda syndrome
Long QT syndrome
Short QT syndrome
Early repolarisation syndrome
What is hypertrophic cardiomyopathy?
Condition where heart muscle becomes thickened
Caused by mutations in genes encoding sarcomeric proteins = myocardial disarray
Increased risk of VT/VF
Hypertrophic cardiomyopathy ECG features:
LVH + strain pattern
Deep, narrow (“dagger-like”) Q waves in lateral and inferior leads
Apical HCM = Gaint T wave inversion (asymmetrical)
What is arrhythmogenic right ventricular cardiomyopathy?
Mutations that cause desmosomal abnormality = causes fibrofatty replacement of RV muscle
(can also include LV muscle)
can trip into VT/VF
Arrhythmogenic right ventricular cardiomyopathy ECG features:
RBBB
Inverted T waves V1-3
Slurred S waves or epsilon waves V1-V3
Inferior/lateral T wave inversion = shows LV involvement
What is Brugada syndrome?
Sodium ion channel abnormality in RV epicardium
SCD due to fast polymorphic VT during rest/sleep
Brugada syndrome ECG features:
Type 1 = Coved ST elevation with T wave inversion V1/2
Type 2 = Saddleback ST elevation with positive T wave V1/2
Brugada sign can be hidden:
Diagnosis recommends moving V1/2 electrodes up to 2nd and 3rd intercostal spaces
Can also be revealed by…
* Na channel blockers
* Fever
* Beta blockers
* Tricyclic antidepressants
* Alcohol toxicity
* Cocaine toxicity
Ajmaline challenge:
Used to check for Brugada syndrome
What is long QT syndrome?
Inherited ion channel abnormality
Prolonged or delayed ventricular repolarisation
Increased risk of lethal ventricular arrhythmias
Females ≥460ms
Males ≥450ms
QTc (ms) =
QT (ms) divided by square root of RR (s)
Triggers for cardiac events in Long QT type 1
vigorous exercise - swimming/diving
Triggers for cardiac events in Long QT type 2
Auditory stimuli – alarm clock, phone, door bell, ambulance siren, door slam – esp on waking Emotional stress, anger
Triggers for cardiac events in Long QT type 3
Sleep or rest without arousal
What is short QT syndrome?
<340ms QT interval
Inherited
May cause AF, ventricular arrhythmias, SCD
Other causes of short QT: digoxin toxicity, hypercalcaemia
What is early repolarisation syndrome?
early repolarisation is usually benign - occasionally a marker for sudden cardiac death
ST elevation + J waves
J wave = slurred or notched
Causes of Left Ventricular Hypertrophy…
Hypertension
Aortic stenosis
Coarctation of the aorta
Cardiomyopathies
LVH ECG:
S wave in V1 + R wave in V5 or V6 >3.5mV
R wave in aVL ≥ 1.1mV
T wave inversion and ST depression in I, aVL, V5 and V6
Voltage for LVH may be present in the absence of LVH if:
Thin build
Young patient
No ST changes will be seen
Causes of Right Ventricular Hypertrophy …
Chronic obstructive pulmonary disease
diopathic pulmonary hypertension
Pulmonary stenosis
Complex congenital heart disease
RVH ECG:
R wave in V1 + S wave in V5 or V6 ≥1.1mV (11mm)
Dominant R wave in V1
S wave in V6
Right axis deviation
Left atrial abnormality (enlargement) causes…
Any disease of the LV which impairs function
LVH
Cardiomyopathy
Mitral valve disease
Left atrial abnormality (enlargement) ECG:
P mitrale (broad P)
Lead II = Wide, notched (bifid) P waves (≥3mm)
V1 = Negative component of P wave has a width and depth of 1 mm or more (and is bigger than the initial positive deflection)
Right atrial abnormality (enlargement) ECG:
P Pulmonale (tall peaked P)
Lead II = P wave height ≥ 2.5 mm
V1 = Tall upright initial P wave deflection
≥1.5mm
Right atrial abnormality (enlargement) causes…
Pulmonary hypertension
RVH
Cardiomyopathy
Tricuspid stenosis or regurgitation
Congenital heart disease (e.g. Ebstein’s anomaly)
What is dilated cardiomyopathy?
All chambers dilated
Poor LV function
Can lead to HF
Multiple causes: familial, viral, alcoholic
Dilated cardiomyopathy
No specific ECG findings although ECG is usually very abnormal
LBBB common
Combination of LBBB & RAD
ST / T wave changes common
AF and VPBs common
LA abnormality (enlargement)
Combination of low voltage QRS in limb leads & high voltage QRS in chest leads
What is restrictive cardiomyopathy?
Eg cardiac amyloidosis (Thick heart walls but not LVH)
* Rare
* Several forms
* Infiltrative process
* Usually systemic: multi-organ
* Initially LV diastolic dysfunction
Restrictive Cardiomyopathy: Amyloidosis ECG features
Low voltage of all waveforms, particularly limb leads ≥ 5 mm
Marked LAD
QS waves in V1-3 (simulating anteroseptal MI)
Prolonged AV conduction time
T wave inversion
Atrial Septal Defect ECG
RBBB pattern
rsR’ in V1 + RAD = secundum ASD
rsR’ in V1 + LAD = primum ASD
Can have Crochetage sign (notch at peak of R wave in inferior leads)
Subarachnoid haemorrhage ECG
Widespread deep T wave inversion
Can mimic ACS ecg
Stroke ECG
widespread T wave inversion
long QTc
Muscular dystrophy
Deep lateral Q waves
Dominant R in V1
Conduction abnormalities/ventricular arrhythmias are common
What is Friedreich’s Ataxia?
an autosomal-recessive genetic disease that causes difficulty walking, a loss of coordination in the arms and legs, and impaired speech that worsens over time
patients can develop hypertrophic cardiomyopathy
Friedreich’s Ataxia ECG
ST depression and T wave inversion common
Dextrocardia
Heart is in the right side of the chest and points to the right
negative P, QRS and T waves in lead I
QRS negative & gets smaller from V1 to V6
Normal R wave progression with right-sided chest leads
There are only 2 possible causes of a negative P wave and a negative QRS in lead I…
Dextrocardia
Transposal of right and left arm connections
QRS progression in chest leads is normal with transposed arm connections
Potential massive Pulmonary Embolism ECG characteristics:
S1, Q3, T3 = large S wave in I, large Q wave in III, T wave inversion in III
Sinus tachycardia
T wave inversion in right chest leads
Right axis deviation
Transient RBBB
ST elevation in V1
Acute Pericarditis ECG
Inflammation of the pericardium
1st Stage
Widespread concave upwards ST elevation
(due to epicardial injury)
PR segment depression
2nd Stage
ST segment elevation resolves
Widespread T wave inversion develops
After several weeks, ECG is usually normal
If significant pericardial effusion develops, ECG will show…
Low voltage waveforms
Electrical alternans (alternate beats vary dramatically in size or axis as the heart swings in the pericardial fluid)
Non-ischaemic chest pain ECGs:
Pulmonary embolism:
* S1Q3T3 pattern
* T wave inversion V1-V3
* Sinus tachycardia
Pericarditis:
* Concave upwards ST↑
* ST ↑ < 5mm
* ST↑ widespread
* No pathological q waves
Myocarditis ECG findings:
No ECG abnormality specific for myocarditis
Most common finding in acute myocarditis is diffuse T wave changes (particularly inverted T waves)
ST elevation, ventricular arrhythmias and heart block may be found
Myocarditis:
May mimic acute MI clinically and electrocardiographically
MRI shows myocardial inflammation
Myocarditis and pericarditis often co-exist
unipolar pacing =
big spikes
Long QT syndrome types:
1 = run (exercise)
2 = boo (stimulant)
3 = zzz (sleep)
bipolar pacing =
small spikes
hypokalaemia =
T wave inversion + ST depression
U wave
hyperkaleamia =
T wave peaked9
P wave flat
PR interval prolonged
wide QRS complex
Pulmonary embolism =
DVT migrates to lungs
S1 Q3 T3
tachycardia
Right ventricular strain pattern (T wave inversion anterior + inferior leads)
RAD
RAE (P pulmonale)
RBBB
LVH =
LAD
Deep S waves in V1
Tall R waves in V5/6
R wave in lead V5/6 + S wave in V1 = >35mm
R wave in lead all >11mm
Any R wave >25mm
Strain pattern
Causes of LVH
Hypertension
aortic stenosis
mitral regurgitation
coarctation of the aorta
HCM
RVH =
RAD
Dominant R wave in V1
Dominant S wave in V5/6
Right ventricular strain pattern - T wave inversion/ST depression in anterior and inferior leads
Causes of RAD
RVH
RV strain (pulmonary embolism)
COPD
Dextrocardia
Causes of LAD
LVH
LBBB
ASD
Chest leads swapped
abnormal R wave progression
V5/6 too medial
S waves
Swapping the black lead with another
flat lines
V4-V6 too low
4th should be in 5th intercostal space and 5/6 should be horizontal
if too low there will be low R wave amplitude
V1/2 too high
V1 looks like aVR
V2 looks like aVL
RSR
negative P waves
hypothyroidism =
Brady
T wave inversion
low voltages
hyperthyroidism =
tachy
AF common
RBBB/LAFB (RBBB +LAD)
left anterior fascicle block
LAD with no other cause
S wave in V6
no LBBB
no Q waves
left posterior fascicular block
RAD with no other cause
broad QRS tachycardia =
VT unless proven otherwise
