Question 26.3
Question 26.3
Please note: The following ECGs have all been recorded at 25 mm/sec and gain setting of 10 mm/mVe 26.1
Describe the ECG shown on page 10 (Figure 3). (20% marks)
List four conditions that are associated with the axis abnormality seen in this ECG. (10% marks)
College Answer
a)
- Rightward QRS axis
- Peaked P waves in the inferior leads > 2.5 mm (P pulmonale) with a rightward P-wave axis (inverted in aVL)
- Clockwise rotation of the heart with a delayed R/S transition point (transitional lead = V5). Right ventricular hypertrophy criteria present Right axis deviation of +110° or more.
- Dominant R wave in V1 (> 7 mm tall or R/S ratio > 1).
- Dominant S wave in V5 or V6 (> 7 mm deep or R/S ratio < 1).
- QRS duration < 120 ms (i.e. changes not due to RBBB).
- Right ventricular strain pattern = ST depression / T wave inversion in the right precordial (V14) and inferior (II, III, aVF) leads.
- Deep S waves in the lateral leads (I, aVL, V5-V6).
b) Right ventricular hypertrophy
- Left posterior hemi block
- Lateral myocardial infarction
- Acute right heart strain
- Drug toxicity (e.g. TCAs)
Discussion
This is an ECG of RV hypetrophy stolen from LITFL.
Edward Burns gives the following electrocardiographic features:
Diagnostic criteria
- Right axis deviation of +110° or more.
- Dominant R wave in V1 (> 7mm tall or R/S ratio > 1).
- Dominant S wave in V5 or V6 (> 7mm deep or R/S ratio < 1).
- QRS duration < 120ms (i.e. changes not due to RBBB).
Supporting criteria
- Right atrial enlargement (P pulmonale).
- Right ventricular strain pattern = ST depression / T wave inversion in the right precordial (V1-4) and inferior (II, III, aVF) leads.
- S1 S2 S3 pattern = far right axis deviation with dominant S waves in leads I, II and III.
- Deep S waves in the lateral leads (I, aVL, V5-V6).
Other abnormalities caused by RVH
Right bundle branch block (complete or incomplete).