A 50-something presented with epigastric and chest pain.
Here is his ECG:
|What do you think? QTc 388 ms.
INCOMPLETE RIGHT BUNDLE BRANCH BLOCK
ST ELEVATION, CONSIDER SEPTAL INJURY
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:
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)
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
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:
Here are other cases of saddleback STE: