Inferior ST elevation under 1 mm, too small for STEMI criteria, with bulky inferior T waves and the giveaway: ST depression and an inverted T in aVL, the one lead that looks straight back at the inferior wall.
Not every occlusion reads out in millimeters. Here the inferior ST is up less than 1 mm, but the T waves in II, III and aVF are bulky and aVL shows ST depression with an inverted T. aVL is the lead most directly opposite the inferior wall, and in the studies Smith's group cites, virtually every inferior STEMI had some ST depression there while pericarditis had none. So inferior ST elevation of any size with depression in aVL is an occlusion until proven otherwise. Transmit, run V4R for the right ventricle, and repeat the 12-lead.
Each is a standard 12-lead: 2.5 seconds of each lead in four columns, with 10 seconds of lead II along the bottom, drawn to scale (25 mm a second, 10 mm a millivolt). The measurements are under each one.
ST elevation in II, III and aVF, with reciprocal ST depression in aVL.
Widespread, modest, concave ST elevation with PR depression, and the only ST depression in aVR (and V1), where the PR is elevated instead.
Sinus rhythm, a normal axis, normal intervals, R waves growing from V1 to V5, and no ST elevation or depression.
Concave ST elevation in V2-V5 with a notched J point and tall, slightly lopsided T waves, no reciprocal depression, and a V6 ST under a quarter of its T wave's height. A normal variant, mostly in the young.
The ECG tool in the app gives you a new 12-lead every time and walks you through reading it: rate, QRS, axis, then where the ST is up and down. It's part of the Paramedic level, and you can try 5 ECGs a day free.
Try the 12-lead drill
EMS Registry Ready