In a single centre observational study over 10 years of patients undergoing acute PCI of the left anterior descending (LAD) artery, 35 of 1890 (2%) had a distinct non-ST elevation ECG pattern.
The ECG showed ST-segment depression at the J-point of at least 1 mm in the precordial leads with upsloping ST-segments continuing into tall, symmetrical T-waves. Patients also showed a mean J-point elevation of approximately 0.5 mm in lead aVR.
This novel ECG pattern resolved after reperfusion in all included patients.
The authors caution that these electrocardiographic changes may be missed or misdiagnosed as reversible ischaemia, which might substantially delay the transportation to a PCI centre or the start of reperfusion therapy
The authors conclude: “It is important for cardiologists and emergency care physicians to recognise this distinct ECG pattern, so they can triage such patients for immediate reperfusion therapy.”

Persistent precordial “hyperacute” T-waves signify proximal left anterior descending artery occlusion
Heart. 2009 Oct;95(20):1701-6