tag:blogger.com,1999:blog-549949223388475481.post2184759823882031266..comments2024-03-28T14:02:08.119-05:00Comments on Dr. Smith's ECG Blog: What could this rhythm be? And what is going on after it breaks?Unknownnoreply@blogger.comBlogger10125tag:blogger.com,1999:blog-549949223388475481.post-9288470599879375212019-11-15T12:26:14.327-06:002019-11-15T12:26:14.327-06:00The pattern of ST segment deviation that we see he...The pattern of ST segment deviation that we see here (ie, ST depression in no less than 8 leads — with ST elevation in aVR & V1) is suggestive of subendocardial ischemia and NOT digitalis effect or digitalis toxicity. That said — given the heart rate in ECG #1 ( ~210/minute) — the chances are great that the principal cause of these ST-T wave changes is tachycardia — which can be determined by repeating the ECG after conversion to sinus rhythm (in which case most, if not all of the ST depression and elevation will probably resolve). Alas, in this case — ECG #2 (in my Figure-1 above) shows that there is preexcitation (WPW) in the post-conversion tracing — so we are not really able to assess serial ST-T wave changes. In any event — these ST-T wave changes are unlikely to be the result of digitalis effect or toxicity — :)ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-37924754931106808442019-11-13T14:40:06.565-06:002019-11-13T14:40:06.565-06:00There are ST depression in inferior and V3-V4 lead...There are ST depression in inferior and V3-V4 leads, but ST elevation in V2-3 and aVR.These depression Coud be pharmacological effect of digitalis?O Poder da Eletrocardiografiahttps://www.blogger.com/profile/11143192155299060176noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-78800736595406736882019-10-24T11:29:26.702-05:002019-10-24T11:29:26.702-05:00I think of it simply: if it looks like LBBB (like ...I think of it simply: if it looks like LBBB (like this one), then there is a right sided AP (depolarization coming right to left, as in LBBB). If it looks like RBBB (like this one), then there is a left sided AP (depolarization coming left to right, as in RBBB).Steve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-49937879165286076632019-10-23T14:04:59.817-05:002019-10-23T14:04:59.817-05:00Sorry, I don't have access to the EP study res...Sorry, I don't have access to the EP study results.Pendellhttps://www.blogger.com/profile/01445330667624442976noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-6051195341171700932019-10-23T13:53:14.253-05:002019-10-23T13:53:14.253-05:00@ Anonymous — Thanks for your comment. I will ask ...@ Anonymous — Thanks for your comment. I will ask Drs. Meyers and Smith if they have any information on the official EP result for this patient. In the meantime — I’ll share my synthesis of the best references I’ve seen for predicting the likely localization of the AP (Accessory Pathway) — References that I used, and details of the synthesized Algorithm I developed can be found HERE — http://ecg-interpretation.blogspot.com/2013/10/ecg-interpretation-review-76-anterior.html — For this case, I’ll use the post-conversion tracing that shows WPW ( = ECG #2 in my Figure-1 above, in which BLUE arrows highlight some of the delta waves that we can see). The 1st Step in my method is to determine the area of Transition (where the R wave becomes greater than the S wave in the chest leads). This looks to be between leads V3-to-V4 — therefore begin with STEP B-4 in my algorithm. While admittedly difficult to tell (because the limits of the delta wave in lead II are not clearly demarcated) — I took the delta wave in lead II to be less than 1.0mV (10 mm) — which suggests the AP is in the RV Free Wall. Next according to the algorithm — GO to STEP B-5 — in which we are to measure the delta wave frontal axis — which is positive, because the delta wave is positive in both leads I and aVF. This suggests the AP is in the Anterolateral RV Free Wall. NOTE — This algorithm is NOT perfect (I believe NO algorithm is perfect for localizing the AP on ECG prior to EP study) — but I’ve liked this algorithm at the above link, because it is EASY to use (it takes no more than 1-2 minutes) and as accurate as anything I’ve encountered — :)ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-242371833974161862019-10-22T22:28:10.076-05:002019-10-22T22:28:10.076-05:00Great case, sir. Can you update the EPS result? Wh...Great case, sir. Can you update the EPS result? Where is the location of the AP? Thank you :)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-20118034465750098472019-10-21T14:14:32.982-05:002019-10-21T14:14:32.982-05:00@ Anonymous — You are correct! You can have a narr...@ Anonymous — You are correct! You can have a narrow reentry SVT rhythm that does NOT involve an AP (accessory pathway) — in which case the rhythm is termed, “AVNRT”. I indicate this in My Comment above (in the paragraph beginning, “Conclusion”). I suspect your wrote your question before I had a chance to include My Comment (Please realize that I have to wait until AFTER each blog post is published before I get to see the tracings … therefore My Comment is usually delayed by 12-48 hours — :)ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-87488326916594708372019-10-21T10:09:56.687-05:002019-10-21T10:09:56.687-05:00In the initial discussion in states that SVT could...In the initial discussion in states that SVT could be "AVRT [which is SVT in the setting of WPW with an accessory pathway]". I think this isn't quite accurate as a description. WPW suggests that the accessory pathway can conduct top to bottom causing a delta wave. Narrow QRS AVRT doesn't necessarily require an accessory pathway that can conduct top to bottom. Since the QRS is narrow complex on EKG 1 and you can have an accessory pathway that conducts ONLY bottom to top, the ddx would include AVRT but this wouldn't have to be in the setting of WPW syndrome. While AVRT and WPW often live together, they don't have to. Is this right?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-72584117342314704352019-10-17T09:10:16.910-05:002019-10-17T09:10:16.910-05:00@ Anonymous. THANKS for the kind words. LGL ( = Lo...@ Anonymous. THANKS for the kind words. LGL ( = Lown-Ganong-Levine) — is a syndrome that in the past referred to the finding of a short PR interval (<0.12 second, in adults), but a normal (narrow) QRS complex and no delta waves. The thought was that this short PR interval indicated the presence of an AP (accessory pathway) passing from atria-to-ventricles, but without passage through ventricular myocardial muscle that results in slowed conduction with resultant delta waves. With realization that OTHER phenomena not due to existence of an AP may also cause shortening of the PR interval (ie, accelerated conduction through the AV node; an anatomically smaller-than-usual size of the AV node) — application of the term, LGL should now be reserved for cases when there is: i) a short PR interval; ii) an otherwise normal QRS complex (no delta waves!); — AND — iii) clinical documentation of cardiac arrhythmia that may be the result of an AP. In this particular case — since the QRS complex in ECG #2 is wide AND has delta waves — there is evidence of WPW (but this is clearly not LGL) — :)ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-371235589300095102019-10-17T08:24:54.145-05:002019-10-17T08:24:54.145-05:00Thanks again for another great case!
Q. Can LGL S...Thanks again for another great case!<br /><br />Q. Can LGL Syndrom be an option when I interpret short PR interval?<br />Q. Does it exist? <br /><br />Thanks in advance!Anonymousnoreply@blogger.com