Male in his 40’s with chest pressure: what

This 40-some year old patient complained of chest pressure and had this ECG recorded:

See comments and diagnosis below








The providers were a bit worried about this ST elevation and I was in the department, so they showed it to me: my answer took 2 seconds and was unequivocal: LVH and early repolarization, no STEMI.

How did I know this?  Primarily because:

If inferior MI, there would be significant ST depression in aVL.
If anterior MI, there would not be such high voltage, especially in lead V4.

Though the early repol/anterior STEMI formula may give false positives in LVH (I'm actually not sure of this), the value obtained after plugging in STE60V3 = 5 mm, QTc = 400 ms, and R wave V4 = 33 mm = 18.2 (far less than 23.4, strongly arguing against anterior STEMI).  I did not use the formula, but one could do so and be reassured.

My colleagues appropriately did a bedside ultrasound and found completely normal function.  They did admit him for "rule out" and all troponins were negative.

 





Diagnosis: Anterior and "inferior" ST elevation due to LVH and early repolarization

Modified Sgarbossa Rule Published Online: Annals of Emergency Medicine

Link: Diagnosis of ST-Elevation Myocardial Infarction in the Presence of Left Bundle Branch Block With the ST-Elevation to S-Wave Ratio in a Modified Sgarbossa Rule

There are differences between previous posts and the findings in this paper.  

Previously, the best ratio was 0.20.  Due to slight differences in methodology, the final rule uses 0.25.  It is important to realized that the use of 0.20 will result in slightly higher sensitivity and lower specificity for STEMI. 

Also, I did not use the absolute value of the ratio.  Thus, whereas, before, excessive discordance was greater than 0.20, it is now less than -0.25 (less than a negative number).  This may be confusing, but was more accurate in terms of simple arithmetic (dividing a positive number by a negative one).

Thus, for the revised rule, the third component of the rule [greater than or equal to 5 mm discordant ST elevation in leads with a negative QRS (S-wave)] is replaced by a ratio of ST elevation at the J-point, relative to the PR interval (a positive number), divided by the preceding S-wave (a negative number, so the result is a negative number) that is less than or equal to -0.25, was far more sensitive and was more accurate than the Sgarbossa rule at diagnosing coronary occlusion.  Additionally, the discordant ST elevation must be at least 1 mm.  The criteria need to be met in only one lead to be positive.

Furthermore, we found that a simple rule using only any excessive discordance (excessively discordant ST elevation or ST depression in just one lead, without paying attention to concordance), with a ratio less than or equal to -0.30, was the most sensitive (100%), with excellent specificity (88%) and the best accuracy.

Both rules need validation in another study.  We are working on that.

The full text is not free now; I'm not sure if it will be when published in print.

Here are some example cases.

Modified Sgarbossa Rule Published Online: Annals of Emergency Medicine

Link: Diagnosis of ST-Elevation Myocardial Infarction in the Presence of Left Bundle Branch Block With the ST-Elevation to S-Wave Ratio in a Modified Sgarbossa Rule

There are differences between previous posts and the findings in this paper.  

Previously, the best ratio was 0.20.  Due to slight differences in methodology, the final rule uses 0.25.  It is important to realized that the use of 0.20 will result in slightly higher sensitivity and lower specificity for STEMI. 

Also, I did not use the absolute value of the ratio.  Thus, whereas, before, excessive discordance was greater than 0.20, it is now less than -0.25 (less than a negative number).  This may be confusing, but was more accurate in terms of simple arithmetic (dividing a positive number by a negative one).

Thus, for the revised rule, the third component of the rule [greater than or equal to 5 mm discordant ST elevation in leads with a negative QRS (S-wave)] is replaced by a ratio of ST elevation at the J-point, relative to the PR interval (a positive number), divided by the preceding S-wave (a negative number, so the result is a negative number) that is less than or equal to -0.25, was far more sensitive and was more accurate than the Sgarbossa rule at diagnosing coronary occlusion.  Additionally, the discordant ST elevation must be at least 1 mm.  The criteria need to be met in only one lead to be positive.

Furthermore, we found that a simple rule using only any excessive discordance (excessively discordant ST elevation or ST depression in just one lead, without paying attention to concordance), with a ratio less than or equal to -0.30, was the most sensitive (100%), with excellent specificity (88%) and the best accuracy.

Both rules need validation in another study.  We are working on that.

The full text is not free now; I'm not sure if it will be when published in print.

Here are some example cases.