tag:blogger.com,1999:blog-549949223388475481.post8458909698684906389..comments2024-03-28T14:02:08.119-05:00Comments on Dr. Smith's ECG Blog: What is this Regular SVT?Unknownnoreply@blogger.comBlogger6125tag:blogger.com,1999:blog-549949223388475481.post-52478123729450556792019-11-22T22:04:44.958-06:002019-11-22T22:04:44.958-06:00@ Mac — THANKS for your comment! A “picture is wor...@ Mac — THANKS for your comment! A “picture is worth 1,000 words” — so hard to make specific comments on the tracing you had without seeing it … — but to me, the rate is telling. Although in theory ATach may attain atrial rates over 250/minute — that’s just not common — so if the atrial rate in your tracing was ~300/minute — I would think that is very strong evidence favoring AFlutter as the diagnosis. I discuss differentiation between ATach vs AFlutter here — http://ecg-interpretation.blogspot.com/2016/12/ecg-blog-138-svt-av-block-atrial.html — but “Take Home” points are that: i) there are “atypical forms” of AFlutter, in which a “sawtooth” morphology may not be seen — so an isoelectric baseline does not rule out flutter; ii) Sometimes distinction between AFlutter vs ATach can only be made in the EP lab; and iii) Fortunately — this distinction is usually not essential in the short-term (ie, You’ll probably treat both rhythms quite similar in an emergency setting) — and in the longterm, if initial management is refractory — you’ll be referring the patient. Hope that helps — :)ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-69221731526473217562019-11-22T16:20:00.180-06:002019-11-22T16:20:00.180-06:00Thank you Ken! I alway enjoy your comments!
I have...Thank you Ken! I alway enjoy your comments!<br />I have a question: I recently recorded a similar ECG. It had an atrial rate of 300 with 2:1 conduction and a ventricular rate of 150. But the atrial activity showed only in form of small blips with a normal baseline in between. P-Wave axes were distributed as in atrial flutter (negative in the inferior leads and positive in V1). So it had the the atrial rate of atrial flutter but the morphology of atrial tachycardia. Some say you can only call it atrial flutter if you do not have an isoelectric baseline. What do you say?Macnoreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-57727373316869052922019-11-13T14:05:18.207-06:002019-11-13T14:05:18.207-06:00THANKS so much (as always!) Jerry for your comment...THANKS so much (as always!) Jerry for your comments! I could not agree more. Although atrial flutter is NOT an overly common arrhythmia in children — when it occurs, the atrial rate of flutter may be faster, leading to a resultant faster ventricular rate — for JUST the anatomic reasons you mention, with smaller size in the smaller hearts of children leading to a faster atrial rate. As we both emphasize — there are certain “Go To” leads, that with experience one learns exactly how to see those 2:1 atrial deflections (even when they are small and partially hidden) — but important (as you emphasize) to always be sure you search ALL 12 leads when looking for atrial activity. I like to emphasize the adage, “If you have a regular SVT at ~150/minute in an adult, without clear sign of sinus P waves — Think AFlutter UNTIL you prove otherwise — and that way you immediately become MUCH less likely to overlook this diagnosis. THANKS again for your Pearls! — :)ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-80457889949204022812019-11-12T21:47:23.451-06:002019-11-12T21:47:23.451-06:00Great Pearls, Ken!
The question arises "If t...Great Pearls, Ken!<br /><br />The question arises "If the ventricular rate is typically around 150/minute because the atrial rate is typically around 300/minute (with a 2:1 conduction ratio), then why is the atrial rate usually around 300/minute in just about everyone?" The answer lies in the circumference of the tricuspid valve annulus which constitutes the reentrant circuit for typical CW and CCW atrial flutter. That circumference is about the same for almost all normal-sized adults and it results in an atrial cycle length that is very close to 200 msec (or 300 beats/min).<br /><br />I also think that one of the reasons that this dysrhythmia is so often missed is because beginners are taught to look only in Lead II for P waves. V1 is very good for displaying P waves that can't be seen in Lead II. But don't forget about the other chest leads. On many occasions I've had to depend on V4 or V5 to show me the P waves.Jerry W. Jones, MD FACEPhttps://www.medicusofhouston.comnoreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-67635202047047637632019-11-12T15:27:31.420-06:002019-11-12T15:27:31.420-06:00Oi. Muito obrigado pelo seu comentário! (Hi. Thank...Oi. Muito obrigado pelo seu comentário! (Hi. Thanks a lot for your comment!). If I understand your question correctly — YES, there appears to be slight ST segment depression in a number of leads in this tracing — BUT — because the rhythm is AFlutter (Atrial Flutter) — the “flutter waves” are superimposed on the ST segments, and this makes it somewhat difficult to know how much ST depression there really is. The BEST way to tell, will be AFTER the rhythm is converted — to REPEAT the ECG. Chances are there will be much LESS ST depression at that time because: i) the heart rate will be much slower (ie, tachycardia is a common cause of ST depression); and ii) there will no longer be superimposed “flutter waves” once sinus rhythm has been restored. As to your other Questions — it is sometimes difficult to distinguish between AVNRT, AVRT and Atrial Tachycardia. You may be interested in reading the 10/16/2019 case on Dr. Smith’s ECG Blog ( http://hqmeded-ecg.blogspot.com/2019/10/what-could-this-rhythm-be-and-what-is.html ) — which illustrates how the duration of the RP’ interval during the regular SVT rhythm can sometimes help in distinction between AVRT vs AVNRT (discussed in detail in My Comment at the bottom of the page). I discuss some pointers for distinguishing AFlutter from ATach at THIS LINK ( http://ecg-interpretation.blogspot.com/2016/12/ecg-blog-138-svt-av-block-atrial.html ). Finally — regarding the question of HOW to interpret ST-T wave depression, I reviewed in some detail simplified diagnostic considerations when confronted with ST depression in My Comment at the bottom of the page of Dr. Smith’s 10/21/2019 post ( = https://hqmeded-ecg.blogspot.com/2019/10/is-this-st-depression-due-to-lateral.html )ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-63741296357299278212019-11-12T13:26:04.887-06:002019-11-12T13:26:04.887-06:00This post is useful for me!!! I am brazilian medic...This post is useful for me!!! I am brazilian medical student. I want to know if is there ST depression in this tracing and how do i distinct from each other diferential diagnosis, that said, AVNRT, AVRT and Atrial Tachycardia? I am beginning to learn ekg this year, this blog is very amazing!!!O Poder da Eletrocardiografiahttps://www.blogger.com/profile/11143192155299060176noreply@blogger.com