What do these twelve leads show?

Sinus tachycardia with T-wave inversion in the anterior leads and inferiorly

An evolving anteroseptal ST-elevation infarct

A Wellens type B pattern — deep symmetric anterior T inversion in a pain-free patient

Left bundle branch block with secondary T-wave changes

A colleague reads the anterior T inversion as a coronary syndrome. Which feature of this tracing argues against that and for acute right heart strain?

The T waves are inverted inferiorly at the same time as anteriorly

The frontal axis, which is within normal limits

The baseline wanders markedly through the limb leads. How should that change what you do with this tracing?

The praecordial T inversions repeat beat to beat and can be read; the wander does not hide them

Wander of this degree creates the appearance of T inversion where there is none

The tracing is uninterpretable and no decision should be made until it is repeated

Only the limb leads are affected, so the inferior leads must be disregarded entirely

Squiggler

Central chest tightness and breathlessness for two hours

2026-09-19

The case

38-year-old man. Central chest tightness and breathlessness for two hours

Smokes fifteen a day. No regular medication and no previous cardiac history. Flew back from a conference in Singapore three days ago. The tightness came on while he was sitting at his desk and has not eased.

On arrival

HR: 115
SpO₂ (%): 95
Respiratory rate: 22
Temperature (°C): 37
Systolic BP (mmHg): 124
Diastolic BP (mmHg): 78

Diagnosis

Acute pulmonary embolism presenting with anterior T-wave inversion

One of the more specific findings for PE includes negative T waves inferiorly and in V1-V3. That being said, a normal ECG is the most typical finding in all pulmonary embolism cases.

Embed

<script async src="https://www.squiggler.io/embed.js" data-case="central-chest-tightness-and-breathlessness-for-two-hours"></script>

Or, where scripts are stripped:

<iframe src="https://www.squiggler.io/blog/central-chest-tightness-and-breathlessness-for-two-hours/embed" title="Central chest tightness and breathlessness for two hours — ECG case from Squiggler" width="100%" height="900" style="border:0" loading="lazy"></iframe>

This tracing was generated, not recorded. It opens in the studio with every dial live.

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Discussion

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