A young man presented after a syncopal episode.  He felt fine in the ED.  He had no previous cardiac history, but stated that he does have an abnormal baseline ECG.

Here is his ED ECG:

There is a hyperacute T-wave in lead III which is far larger than a small QRS.  There is reciprocal ST depression and and inverted reciprocally hyperacute T-wave in lead aVL and I.  Precordial leads support the diagnosis of STEMI, showing posterior STEMI.

So this young person with syncope and no other symptoms is having a STEMI?

Could it be that this is his abnormal baseline ECG?

NO.

There is no baseline abnormality which looks like this.

There is a condition of baseline inferior ST elevation (“early repolarization” in the limb leads).  We have shown that this never has reciprocal ST depression.  Here is the reference:

Bischof J.  Thompson RP.  Tikkanen J.  Porthan K.  Huikuri H.  Salomaa V.  Smith SW.  ST-segment depression in lead aVL differentiates benign ST elevation from inferior Acute STEMI.  ACEP Research Forum 2012.  Annals of Emergency Medicine 60(4 Suppl):S8-S9; October 2012.

The patient was taken for PCI of 100% thrombotically occluded RCA.  The etiology of the syncope is uncertain, but probably some dysrhythmia related to the inferior STEMI.

Later, his baseline abnormal ECG was obtained.  Here it is.

This is classic “Benign T-wave Inversion”

To learn all about Benign T-wave Inversion, read this.