Saddleback ST Elevation. Is it STEMI? Is it type II Brugada?

A 50-something presented with epigastric and chest pain.

Here is his ECG:

What do you think?  QTc 388 ms.











Computer interpretation:

SINUS RHYTHM
INCOMPLETE RIGHT BUNDLE BRANCH BLOCK
ST ELEVATION, CONSIDER SEPTAL INJURY
***ACUTE MI***

There is a saddleback, which is rarely due to MI.  V2 has the morphology of type II Brugada, as there is a relatively large beta angle, described here:

Explanation
1. Draw a horizontal line from top of r’ wave (black line 1)
2. Draw a horizontal line 5 mm below this (green line 2)
3. Extend the downsloping r’-ST segment (black line 3) until it intersects the green line
4. Measure the base.  

If greater than 3.5 mm, then meets criteria (this is equivalent to a 35 degree beta angle)

However, whenever you see an rSR’, especially with a saddleback, think of lead placement.

Then look at the P-wave in V2.  Is it fully upright?  If not, then there is probable high placement of lead V2.

I went back to look and, indeed, V1 and V2 were placed too high.

I put them in the correct position and we recorded another ECG:

Now the P-wave in V2 is upright.  The lead is placed correctly.
Looks like typical normal variant ST elevation (otherwise known as early repolarization)
QTc 384

You can use the LAD-Early Repol Formula to differentiate this from LAD occlusion:

ST elevation at 60 ms after the J-point, relative to PQ junction (STE60V3), = 2.5mm
QTc by computer = 384
R-wave amplitude in V4 (RAV4) = 19mm
Total QRS amplitude in V2 (QRSV2) = 17.5mm

Any of these calculators work:
Use the iPhone app: SubtleSTEMI
Use the Android app: ECG SMITH
Use the link at the top of the blog.
Use MDcalc.com: https://www.mdcalc.com/subtle-anterior-stemi-calculator-4-variable

4-variable formula: 15.1 (A value less than 18.2 favors early repol.  This value is very low.)

The patient was diagnosed with reflux

Learning Points:

1. Saddleback ST Elevation is almost never STEMI
2. Saddleback STE may be type II Brugada syndrome
3. A Type II mimic may result from leads V1 and V2 placed too high
4.  An inverted P-wave in lead V2 implies lead misplacement too high

Saddleback in STEMI:

Here are the only 2 ECGs with V2 “saddleback” that I have ever seen which really represented an LAD Occlusion:

Anatomy of a Missed LAD Occlusion (classified as a NonSTEMI)


A Very Subtle LAD Occlusion….T-wave in V1??

Here are other cases of saddleback STE:

Is this Saddleback a STEMI??





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