ECG changes Flashcards
What are causes of 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
What are causes of 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
*in the majority of cases, or in a question without qualification, Wolff-Parkinson-White syndrome
What is a bifascicular block?
- combination of RBBB with left anterior or posterior hemiblock
- e.g. RBBB with left axis deviation
What is trascicular block?
- features of bifascicular block + 1st-degree heart block
ECG showing trifascicular block: RBBB + left anterior hemiblock + 1st-degree heart block
Correlation between ECG changes and coronary territories?
What does a new LBBB indicate?point towards a diagnosis of acute coronary syndrome.
Point towards a diagnosis of acute coronary syndrome.
What does digoxin show on ECG?
- down-sloping ST depression (‘reverse tick’)
- flattened/inverted T waves
- short QT interval
- arrhythmias e.g. AV block, bradycardia
What does hypokalaemia show on ECG?
- U waves
- small or 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 shows typical U waves. Note also the borderline PR interval.
What does hypothermia show on an ECG?
- bradycardia
- ‘J’ wave - small hump at the end of the QRS complex
- first degree heart block
- long QT interval
- atrial and ventricular arrhythmias
How do you differentiate between LBBB and RBBB?
One of the most common ways to remember the difference between LBBB and RBBB is WiLLiaM MaRRoW
- in LBBB there is a ‘W’ in V1 and a ‘M’ in V6
- in RBBB there is a ‘M’ in V1 and a ‘W’ in V6
What are causes of LBBB?
Causes of LBBB
- Ischaemic heart disease
- Hypertension
- Aortic stenosis
- Cardiomyopathy
- Rare: idiopathic fibrosis, digoxin toxicity, hyperkalaemia
New LBBB is always pathological and may be a sign of a myocardial infarction. Diagnosing a myocardial infarction for patients with existing LBBB is difficult.
What are the ECG changes seen in acute MI?
- Hyperacute T waves are often the first sign of MI but often only persists for a few minutes
- ST elevation may then develop
- 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
What is the definition of ST elevation?
- new ST elevation at the J-point in two contiguous leads with the cut-off points:
- >=0.2 mV in men or >= 0.15 mV in women in leads V2-V3 and/or >= 0.1 mV in other leads
What are normal ECG variants?
- Sinus bradycardia
- Junctional rhythm
- First degree heart block
- Wenckebach phenomenon
What does increased P wave amplitude indicate?
cor pulmonale
