ECGs Flashcards
what is seen in LBBB?
WiLLiaM MaRRoW
In LBBB there is a ‘W’ in V1 and a ‘M’ in V6
Causes of LBBB?
MI
Hypertension
Aortic stenosis
Cardiomyopathy
Rare: idiopathic fibrosis, digoxin toxicity, hyperkalaemia
Is LBBB always pathological?
Yes, if it is new, always pathological
What is seen on RBBB?
WiLLiaM MaRRoW
in RBBB there is a ‘M’ in V1 and a ‘W’ in V6
Causes of RBBB?
normal variant - more common with increasing age
Right ventricular hypertrophy
Chronically increased right ventricular pressure e.g. cor pulmonale
Pulmonary embolism
MI
Atrial septal defect (ostium secundum)
Cardiomyopathy of myocarditis
Acute MI signs on ECG?
Hyperacute T waves (fat and wide with a more blunted peak) are often the first sign of MI but often only persists for a few minutes
ST elevation may then develop
The T waves typically become inverted within the first 24 hours. The inversion of the T waves can last for days to months
Pathological Q waves develop after several hours to days. This change usually persists indefinitely
Definition of ST elevation MI (STEMI)
Clinical symptoms consistent with ACS (generally of around 20 minutes) with persistent ECG features in 2 or more contiguous leads of:
- 2.5mm (≥ 2.5 small squares) ST elevation in leads V2-3 in men under 40 years, or ≥ 2.0mm ( ≥ 2 small squares) ST elevation in leads V2-3 in men over 40 years
- 1.5mm ST elevation in V2-3 in women
- 1mm ST elevation in other leads
- New LBBB (should be considered new unless there is evidence otherwise)
What does posterior MI cause on an ECG?
ST depression
Causes of peaked T waves?
- hyperkalaemia
- myocardial ischaemia
Causes of inverted T waves?
- MI
- digoxin toxicity
- subarachnoid haemorrhage
- arrhythmogenic right ventricular cardiomyopathy
- pulmonary embolism
- brugada syndrome
Causes of increased P wave amplitude?
cor pulmonale
Causes of broad, notched (bifid) P waves?
Often most pronounced in lead II
often a sign of left atrial enlargement, classically due to mitral stenosis
P waves in AF?
absence of P waves
Bifascicular block?
The combination of RBBB with left anterior or posterior hemiblock
e.g. RBBB with left axis deviation
Trifascicular block
Features of bifascicular block + 1st degree heart block
ECG features of Hypokalaemia?
U waves (immediately follows the T wave)
small of absent T waves (occasionally inversion)
prolong PR interval
ST depression
long QT
in hypokalaemia, U have no Pot and no T, but a long PR and a long QT
ECG: hypothermia
bradycardia
‘J’ wave (Osborne waves) - small hump at the end of the QRS complex
first degree heart block (long PR interval)
long QT interval
atrial and ventricular arrhythmias
Causes of ST depression?
secondary to abnormal QRS (LVH, LBBB, RBBB)
ischaemia
digoxin
hypokalaemia
syndrome X
Digoxin ECG features:
down-sloping ST depression (‘reverse tick’, ‘scooped out’)
flattened/inverted T waves
short QT interval
arrhythmias e.g. AV block, bradycardia
Causes of left axis deviation (LAD)
left anterior hemiblock
left bundle branch block
inferior myocardial infarction
Wolff-Parkinson-White syndrome* - right-sided accessory pathway
hyperkalaemia
congenital: ostium primum ASD, tricuspid atresia
minor LAD in obese people
Causes of right axis deviation (RAD)
right ventricular hypertrophy
left posterior hemiblock
lateral myocardial infarction
chronic lung disease → cor pulmonale
pulmonary embolism
ostium secundum ASD
Wolff-Parkinson-White syndrome* - left-sided accessory pathway
normal in infant < 1 years old
minor RAD in tall people
what is seen in left ventricular hypertrophy
sum of S wave in V1 and R wave in V5 or V6 exceeds 40mm
what is seen in left atrial enlargement?
bifid P wave in lead II with a duration >120ms
In V1 the P wave has a negative terminal portion
what is seen in right atrial enlargement?
tall P waves in both II and V1 with exceed 0.25mV
A short PR interval is seen in?
Wolff-Parkinson-White syndrome
Causes of a prolonged PR interval
idiopathic
ischaemic heart disease
digoxin toxicity
hypokalaemia (rarely)
rheumatic fever
aortic root pathology e.g. abscess secondary to endocarditis
Lyme disease
sarcoidosis
myotonic dystrophy
ECG features: Wellen’s syndrome
Wellen’s syndrome is an ECG pattern that is typically caused by high-grade stenosis in the left anterior descending coronary artery.
The patient’s pain may have resolved at the time of presentation and cardiac enzymes may be normal/minimally elevated.
biphasic or deep T wave inversion in V2-3
minimal ST elevation
no Q waves
Causes of ST elevation ?
myocardial infarction
pericarditis/myocarditis
normal variant - ‘high take-off’
left ventricular aneurysm
Prinzmetal’s angina (coronary artery spasm)
Takotsubo cardiomyopathy
rare: subarachnoid haemorrhage
ECG: First degree heart block
PR interval > 0.2 seconds
Second degree heart block
type 1 (Mobitz I, Wenckebach): progressive prolongation of the PR interval until a dropped beat occurs
type 2 (Mobitz II): PR interval is constant but the P wave is often not followed by a QRS complex
Third degree (complete) heart block
there is no association between the P waves and QRS complexes
the following ECG changes are considered normal variants in an athlete:
Sinus bradycardia
Junctional rhythm
First degree heart block
Mobitz type 1 (wenckebach phenomenon)
