Question:
53 yo Italian F with COPD after eating too much ribollita
Question:
What accounts for the ST segment abnormalities seen in 2, 3 and aVF❓
Answer
Atrial repolarization (Ta wave) from right atrial enlargement accounts for these repolarization changes in 2, 3 and aVF.
Learning Points
The P wave axis is 75⁰, rightward shifted and at the upper limit to be called sinus. The heart rate is 94. The peaked P waves in leads 2, 3 and aVF all exceed 3 mm in height and the P waves in V1 and V2 are entirely upright and exceed 1.5 mm. In leads 2, 3 and aVF, where the P waves are largest, atrial repolarization is evident as a negative deflection (Ta wave) in the respective ST segment of 2, 3 and aVF (see blue arrows). These ST segment abnormalities are due to right atrial enlargement and are not ST segment abnormalities of ventricular origin (1,2).
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References:
1. Surawicz B and TK Knilans. Chou’s Electrocardiography in Clinical Practice, 6th Edition. 2008; Philadelphia. Saunders Elsevier. Pp 42-3 and 240. Addresses how this ST change
can give spurious results for inferior wall ischemia.
2. Schiavone W. EKGaction.com 2019; Supplemental case 86 for Ta wave (LAE) and Supplemental case 87 for Ta wave (RAE).