Prevalence as a STEMI equivalent, % | 18 | 2 |
Chest pain | Intermittent | Present |
Troponin | Slightly elevated or normal | Elevated |
ST segment in precordial leads | Slightly elevated | Depressed |
Preferential precordial leads | V1–V6 | V2–V4 |
T-wave characteristics | Profoundly negative or biphasic and symmetric | Positive and symmetric (hyperacute T waves) |
T-wave morphology | Abrupt take-off of the negative T wave from V2 to V4 | Ascending limb of the T wave commencing below the isoelectric baseline |
Precordial R-wave progression | Normal | Normal |
Pathologic Q waves | No | No |
ST-segment elevation in lead aVR | No | Yes |
Angiographic findings | Critical narrowing of proximal LAD | Occlusion of proximal LAD |
Evolution of the ECG pattern | May evolve into “classic” STEMI within weeks | Stable or evolving into “classic” STEMI |