Here’s the conclusion to 81 year old male CC: Palpitations.
Let’s take another look at the 12-lead ECG.
Some of you expressed concerns about the possibility of the ECG abnormality we sometimes refer to as left ventricular aneurysm (persistent ST-elevation after previous MI).
To put it another way, some of you think this STEMI looks “old”.
Stephen Smith, M.D. of Dr. Smith’s ECG Blog has a decision rule to help distinguish LVA from acute anterior STEMI by looking at the T/QRS ratio in leads V1-V4. T/QRS ratio best distinguishes ventricular aneurysm from anterior myocardial infarction. Am J of Emerg Med 2005 May; 23(3):279-287.
A high T/QRS ratio indicates acute STEMI. A low T/QRS ratio indicates LVA.
To come up with the T/QRS ratio you measure the amplitude of the T wave and divide by the depth of the S-wave.
If there is one lead in V1-V4 with a T/QRS ratio > 0.36, then STEMI is likely.
Or, if the sum of the T-waves in V1-V4 divided by the sum of the S-waves in V1-V4 > 0.22, then STEMI is likely.
Let’s look at the current case.
Lead V4 shows a T/QRS ratio of 0.38 which is suggestive of acute STEMI.
Let’s try the more complicated calculation (TV1+TV2+TV3+TV4 divided by SV1+SV2+SV3+SV4).
1+1.5+6+5 = 13.5
11+13+18+13 = 55
13.5/55 = 0.24 (T/QRS ratio)
Remember, the cut-off is 0.22 so this is very close but favors acute STEMI.
Finally, let’s consider another of Dr. Smith’s ECG interpretation tips: the rule of proportionality.
Lead V5 in this case shows a little bit of ST-elevation but the QRS complex is small. Let’s consider the ST/QRS ratio in this lead.
Here we use PowerPoint to “stretch” the QRS complex while preserving the ST/QRS ratio.
Looks pretty impressive to me!
Another finding that supports acute STEMI is the well formed R-waves in leads V3 and V4.
Typically LVA shows QS-complexes in leads V1-V4.
Diagnosis: Acute anterior STEMI (confirmed with angiography)
See also:
ECG mimics of acute STEM (left ventricular aneurysm)
Excessive discordance as a marker of acute STEMI in LBBB
76 year old female CC: Chest pain – Tako-Tsubo Cardiomyopathy
Wolff-Parkinson-White (WPW) – STEMI Mimic
Very interesting case. I had read (maybe even in Dr. Smith’s book) that the T-waves of LVA tended to be lower than those of acute STEMI, but I had never seen a method with possible cut-offs of the proportions to aid with the diagnosis.
I agree it definitely looked “new” as opposed to “old,” but being not just pain free, but symptom free, for 24 hours did a lot to confuse the picture. Had this patient walked into triage at my hospital (not PCI capable), I know it might have been very difficult to get him transferred for same-day PCI, let alone emergent revascularization as a STEMI. Do you have any information on how the call was handled (STEMI alert or not) or how rapidly the patient got to the cath lab? Thanks a ton for the great teaching you do on this site.
Also, there’s a typo in the sentence under the 12 lead at the top. You refer to it as hypertrophy rather than aneurysm.
Thank you for brining the error to my attention! It has been corrected.
I think the important part of this one was the PMD stating there were “changes”.
“Could I see the prior ECG and could you make a copy for me.”
Good case, although now I have to commit another formula to memory from Dr. Smith! Pretty soon I’m going to have to dust off my multivariate calculus books to read a 12-Lead.
Or carry a flash card!
Hah, that’s exactly what sits behind my accountability tag, 12-Lead flash cards! If I ever fall out they’re going to know I’m allergic to PCN and have too much free time on my hands.
To VinceD :
I think that it can not be considered as a direct alert case(symptom free for 24 hours), but I can not see any Q-waves so I think that acute PCI would be the case (“there is myocardium to save”).