ECG Flashcards
Describe the polarity of lead I and lead aVF in left axis deviation?
Lead I: +ve
Lead aVF: -ve
What are the common causes of left axis deviation?
- Normal variant (increases with age)
- LVH
- LBBB
- Left anterior fascicular block
- Inferior MI
- Wolff-Parkinson-White syndrome
Describe the polarity of lead I and lead aVF in right axis deviation?
Lead I: -ve
Lead aVF: +ve
What are the common causes of right axis deviation?
- Normal variant (neonates)
- RVH
- RBBB
- Left posterior fascicular block
- Anterolateral MI
- RV strain (PE, COPD, pulmonary HTN, pulmonary stenosis)
Describe the polarity of lead I and lead aVF in extreme right axis deviation?
Lead I: -ve
Lead aVF: -ve
What are the common causes of extreme right axis deviation?
- Severe RVH
- Lateral MI
Describe the appearance of STEMI in its early stages on ECG.
Hyperacute = peaked T wave (no ST elevation)
ST elevation:
- anteroseptal = V1-V2
- anteroapical = V3-V4
- anterolateral = V5-V6
- lateral = I and aVL
- inferior = II, III, aVF
- posterior = V7-V9
Describe the appearance of STEMI in its intermediate stages on ECG.
- Absence of R wave
- T wave inversion
- Pathological Q wave
Describe the appearance of AF on ECG.
- Irregularly irregular RR intervals
- Tachycardia
- Indiscernible P waves
- Narrow QRS complex (<0.12 seconds)
Which acute event might demonstrate AF on ECG?
Thromboembolic event –> Stroke/TIA
Describe the appearance of LBBB on ECG.
- No R wave in lead V1
- Deep S waves (forming characteristic W shape)
- Wide, notched R waves in leads I, aVL, V5, and V6 (characteristic M shape)
Which acute event might demonstrate LBBB on ECG?
MI
Describe the appearance of RBBB on ECG.
- An rsr’, rsR’, or rSR’ complete (characteristic ‘rabbit ears’ or M shape) in leads V1 and V2
- Tall secondary R wave in lead V1
- Wide, slurred S wave in leads I, V5, and V6 (W shape)
Which condition might demonstrate RBBB on ECG?
COPD
PE
Describe the appearance of acute pericarditis on ECG.
- Diffuse (saddle-shaped) ST segment elevation
- Diffuse PR segment depressions
- T wave inversions
Describe the appearance of cardiac tamponade on ECG.
- Tachycardia
- Low voltage QRS
- Electrical alternans
Describe the appearance of hypokalaemia on ECG.
- Flattened T waves
- ST depression
- Presence of U waves
Describe the appearance of hyperkalaemia on ECG.
- QRS complex widening
- Peaked T waves
- Widening and flattening of P wave
Describe the appearance of hypocalcaemia on ECG.
Prolonged QT interval
Describe the appearance of hypercalcaemia on ECG.
Shortened QT interval
Describe the appearance of hypomagnesaemia on ECG.
Prolonged PR and QT intervals
Describe the appearance of right atrial enlargement on ECG.
P pulmonale (tall P wave)
In which condition is P pulmonale/RA enlargement commonly found?
COPD
Describe the appearance of left atrial enlargement on ECG.
P mitrale (P wave is m shape)
In which condition is P mitrale/LA enlargement commonly found?
Jugular venous distension in restrictive cardiomyopathy
Describe the appearance of LVH on ECG.
- Sokolow-Lyon criteria: RV5 or RV6 + SV1 or SV2 ≥ 3.5 mV
- Left ventricular strain pattern: ST depression with T wave inversion in the left precordial leads in a resting ECG
In which condition is LVH commonly found?
- Aortic stenosis
- HTN
- Coarctation of the aorta
Describe the appearance of RVH on ECG.
- Right axis deviation
- Dominant R wave in lead V1 (R wave > 0.6 mV or R/S > 1)
- Deep S wave in lead V5 (> 1 mV) or V6 (> 0.3 mV)
- Sokolow-Lyon criteria: RV1 or R2 + SV5 or S6 ≥ 1.05 mV
In which conditions is RVH commonly found?
- Pulmonary HTN
- Pulmonary embolism
- COPD
