tag:blogger.com,1999:blog-549949223388475481.post5687440534956549544..comments2024-03-26T22:42:04.176-05:00Comments on Dr. Smith's ECG Blog: A 58 year old collapses in the hot sunUnknownnoreply@blogger.comBlogger5125tag:blogger.com,1999:blog-549949223388475481.post-92972555464498052020-09-18T08:23:44.139-05:002020-09-18T08:23:44.139-05:00Jerry,
2 things:
1) In the study in JEM, I did not...Jerry,<br />2 things:<br />1) In the study in JEM, I did not look for notching. In the study where we derived the 3 variable formula (it is very interesting and I recommend reading the whole study), we found J-point notching in 14% of subtle LAD occlusion.<br />2) Early repol usually has STE in inferior leads and in lateral leads V4-V6, but much less commonly in I and aVL. This is because the ST vector in early repol is most commonly towards lead II (which is similar to V5 and V6), resulting in STE in II > aVF > III, but present in all three leads. There is NOT usually STE in I and aVL. There are cases of normal variant STE in I and aVL, but they are not common and therefore are much more likely to mimic OMI. So any ST depression in lead III is likely to be OMI: early repol would usually manifest ST ELEVATION in lead III.<br />SteveSteve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-24064226814134268632020-09-17T08:17:15.617-05:002020-09-17T08:17:15.617-05:00THANKS so much for your comments Jerry — with whic...THANKS so much for your comments Jerry — with which I totally agree! The SHAPE of the ST-T wave in lead III (especially given the notch in lead III !!!) could simply be a “mirror image” of a repolarization variant change for the reasons you cite related to Einthoven Equation relationships. But even though the ST segment is not depressed in lead aVF — I thought the SHAPE of the ST segment in aVF was abnormal (ie, to me, clearly straighter than it should be). Of course, because the amplitude in lead aVF is tiny — everything is “miniaturized” … — but I don’t think the shape of the ST-T wave in aVF is “normal”. And the problem with inferior lead reciprocal changes is that while ideally we would see them in all 3 of the inferior leads, sometimes they are only seen in leads III and aVF … — therefore (as you so appropriately state) — Best to favor “caution over assumption”.ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-59520979743717886972020-09-16T21:25:11.980-05:002020-09-16T21:25:11.980-05:00Excellent presentation and I totally agree.
A que...Excellent presentation and I totally agree.<br /><br />A question for Steve, but if you (Ken) know the answer then feel free to respond. In the study in which Steve ascertained that 40% (or more) of anterior STEMIs have upwardly concave ST segments, did any of those segments have the J-point notch commonly associated with normal variant (early repol)?<br /><br />Another question: I really don't see any ST depression in the inferior leads except for Lead III. But Lead III has a special relationship with Leads I and II and also with Leads aVL and aVF that - I feel - is unassociated with the issue of "reciprocal change." Based on Einthoven's Equation, Lead III = Lead II - Lead I and Lead III also equals Lead aVF - Lead aVL. The presence of early repol in Leads I and aVL would be expected to result in the morphology seen in Lead III - without any issue of reciprocity or acute epicardial ischemia. Early repolarization is said to not exhibit any reciprocal changes and, in this ECG, I think that still holds true. However, I certainly agree that there was a lot going on that favored caution over assumption.<br /><br />Excellent case, by the way, and (thankfully) much better management than the previous case you posted.<br /><br />Jerry W. Jones, MD FACEP FAAEM<br />https://medicusofhouston.comDouble Downhttps://www.blogger.com/profile/09589348333176062815noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-52101692078949482542020-09-15T21:24:48.962-05:002020-09-15T21:24:48.962-05:00Yes it is true that the finding of a negative P wa...Yes it is true that the finding of a negative P wave in leads V1 or V2 may be the result of faulty lead placement (ie, placing leads V1,V2 by 1 or 2 interspaces too high on the chest). I review this and 2 other clues to V1,V2 misplacement in My Comment at the bottom of the November 4, 2018 post (https://hqmeded-ecg.blogspot.com/2018/11/chest-pain-and-q-waves-in-v1-and-v2-is.html ). But I also emphasize in this Nov. 4 post in my section on “Potential Caveats regarding the 3 Clues” — that these clues are not infallible indicators of lead misplacement. These clues work best when ALL 3 of the findings I suggest are present — especially when the P wave, QRS and T wave in leads aVR, V1 and V2 all look very similar to each other (as they do in my Figure-1 in the Nov. 4, 2018 example). As per the Caveats I list — one may sometimes normally see a prominent negative component to the P wave in lead V1 — especially when there is left atrial enlargement. And when there is an intra-atrial conduction defect — you can see anything regarding morphology in many of the P waves on the tracing.<br /><br />So, in the Sept. 15, 2020 case — although there IS a negative component to the P waves in all 3 of the leads I list (aVR, V1, V2) — P wave morphology looks quite different (especially the biphasic P in lead V2) — the only one of these 3 leads with an rSr’ complex is aVR (and aVR so commonly shows this as a normal finding) — and QRS morphology looks completely different in each of these 3 leads. As to P wave morphology — at least 4 of the 12 leads in the Sept. 15 case show notched P waves, and that suggests there may be an intra-atrial conduction defect. BOTTOM Line: I didn’t think there was lead misplacement of V1 and V2 in this case.ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-16686694612970235862020-09-15T12:45:34.663-05:002020-09-15T12:45:34.663-05:00What about lead misplacement in V1-V2 based on abn...What about lead misplacement in V1-V2 based on abnormal P wave morphology? (quite negative in V1 and biphasic in V2). Could this be responsible for the STEMI pattern?Anonymoushttps://www.blogger.com/profile/06594580595236129304noreply@blogger.com