Stress echo training › Guides › ECG
The ECG during stress echo
The ECG is recorded throughout a stress echo and is part of the report, but the wall motion response carries more weight. Read the resting ECG first, because it decides whether ST changes during stress can be interpreted at all.
Resting ECG
- Pathological Q waves: a previous transmural infarct in that territory. They do not exclude viability: judge contractile reserve on the echo.
- LBBB or ventricular pacing: ST changes during stress cannot be interpreted for ischaemia. The septum also moves abnormally at every stage while it thickens normally.
- Resting ST/T abnormalities (LVH with strain, digoxin): further ST depression with stress is not diagnostic.
During stress
| Finding | Meaning |
|---|---|
| ST depression | Possible ischaemia, but less specific than wall motion. With a normal hyperdynamic wall-motion response the echo result is negative (a false-positive ECG, more common in women and with LVH). |
| ST elevation in leads without Q waves | Transmural ischaemia, usually proximal LAD or left main: high risk and an indication to stop. |
| ST elevation in leads with Q waves | Usually reflects a dyskinetic or aneurysmal infarct wall rather than new ischaemia. Interpret it with the wall motion. |
| Ventricular ectopics | Common with dobutamine and not by themselves a sign of ischaemia. Grade wall motion on sinus beats. |
Putting it together
Report the resting ECG, the ST response and any arrhythmia separately, then give the overall conclusion from the wall motion. A positive ECG with normal wall motion is a negative stress echo. An uninterpretable ECG does not make the test non-diagnostic if the wall motion is diagnostic.
The simulator shows a monitoring ECG strip under every loop, with Q waves, ST depression or elevation, LBBB and ectopics generated for each case and stage.
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