tag:blogger.com,1999:blog-549949223388475481.post1800345141427227601..comments2024-03-26T22:42:04.176-05:00Comments on Dr. Smith's ECG Blog: A Very Fast Regular Narrow Complex, Followed by an Equally Fast Regular Wide ComplexUnknownnoreply@blogger.comBlogger23125tag:blogger.com,1999:blog-549949223388475481.post-32001391017487575532020-11-13T12:41:43.460-06:002020-11-13T12:41:43.460-06:00@ Agni Khan — Please CHECK OUT My Comment at the b...@ Agni Khan — Please CHECK OUT My Comment at the bottom of the page in our March 6, 2020 post (GO TO — https://hqmeded-ecg.blogspot.com/2020/03/new-onset-heart-failure-and-frequent.html ) — as I explain and illustrate your question in detail in My Comment at the bottom of the page — :)ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-36408544266109884602020-11-13T06:21:10.291-06:002020-11-13T06:21:10.291-06:00How to differentiate between AVRT and AVNRT when r...How to differentiate between AVRT and AVNRT when retrograde P-waves are present?Agni Khanhttps://www.blogger.com/profile/16804099177818273435noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-57336357369414446572015-06-18T15:42:04.736-05:002015-06-18T15:42:04.736-05:00Jerry,
Great thoughts. Thanks.
SteveJerry,<br />Great thoughts. Thanks.<br />SteveSteve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-35871170991234946092015-06-17T21:59:36.414-05:002015-06-17T21:59:36.414-05:00Steve...
This case looks like a classic episode o...Steve...<br /><br />This case looks like a classic episode of SVT with aberrancy due to concealed transseptal conduction. A slight delay in one of the bundle branches (which may not be detectable on the 12-lead ECG) allows conduction through the septum to the other bundle branch. This is why some SVTs have continued wide QRS complexes that can't be explained by the Ashman phenomenon (which would explain only the first aberrant complex). Typically, there is no discernible break in the rhythm because it often takes only a few milliseconds to set up the delay. The PR interval shouldn't change because one or the other bundle branch will fire right on time.<br /><br />This will produce a narrow complex tachycardia that suddenly becomes a wide complex tachycardia at basically the same rate.<br /><br />Charles Fisch wrote about this phenomenon at length in some of his books.<br /><br />"Electrocardiography of Complex Arrhythmias" by Charles Fisch addresses this phenomenon numerous times. It's an incredible book for anyone interested in complex dysrhythmias (but unfortunately out-of-print).<br /><br />Jerry W. Jones, MD FACEP FAAEMJerry W. Jones, MD FACEP FAAEMhttps://www.blogger.com/profile/10333187745825224414noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-6675000487651510162014-09-01T06:13:52.062-05:002014-09-01T06:13:52.062-05:00Aldo,
Thanks! I wasn't there and so don't ...Aldo,<br />Thanks! I wasn't there and so don't have that data. That might have shown it, but that does presuppose that the sinus node would have recovered from the adenosine faster than the AV node, which is not a given.<br />Steve SmithSteve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-45051613010997488672014-08-30T16:40:16.297-05:002014-08-30T16:40:16.297-05:00Hi Dr.Smith,
and really great case, once again.
I...Hi Dr.Smith,<br />and really great case, once again.<br /><br />I think it would have been very interesting to look at the ECG while (or just after) giving Adenosine, because I think it could also prove your theory: assuming there were a concealed conduction with a fast AV-Node, thus not developing Delta-Waves on the baseline ECG (3rd one), if we block completely the AV-Node with Adenosine than we should expect some P-Waves followed by a very large QRS (though the accessory pathway). This phenomenon is practically what we fear when giving Adenosine bei Aflutter+WPW (thus contraindicated).<br /><br />Isn´t it?<br /><br />Looking forward for the definitive diagnosis.<br /><br />Greets from Germany<br /><br />AldoUnknownhttps://www.blogger.com/profile/14354392984719020203noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-83984214942417147442014-08-26T18:20:38.014-05:002014-08-26T18:20:38.014-05:00Thank you Gautam. Keep the great comments coming!...Thank you Gautam. Keep the great comments coming!<br />SteveSteve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-87843577261132634002014-08-26T11:05:34.933-05:002014-08-26T11:05:34.933-05:00There are case reports of atrial flutter terminati...There are case reports of atrial flutter termination with adenosine (not suggesting this occurred), or possibly the flutter waves during the AVN blockade were subtle enough to go unnoticed. Strips from the conversion could rule this out as a possibility. V4 in ECG #2 sure looks "fluttery"...<br /><br />That being said...I think the first ECG strongly suggests orthodromic AVRT and the second ECG (given the first) strongly suggests antidromic AVRT. I'm with Ken that aberrancy can be considered as well given the marked change in both frontal axis and Z-axis (perhaps this leans more to AVRT?).<br /><br />Looking forward to the EP study results!Christopherhttps://www.blogger.com/profile/11415988855392944633noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-83294013424587981522014-08-26T04:08:45.394-05:002014-08-26T04:08:45.394-05:00Thank you Dr Smith. I am a general and interventio...Thank you Dr Smith. I am a general and interventional cardiologist. I have been following your blog with keen interest for the past few months and found it extremely informative. <br />GautamGautamhttps://www.blogger.com/profile/03952480792611560421noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-81213832037748304632014-08-25T22:32:42.185-05:002014-08-25T22:32:42.185-05:00Gautam,
That is the best explanation I have seen y...Gautam,<br />That is the best explanation I have seen yet!<br />Are you an electrophysiologist?<br />Steve SmithSteve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-34494039015442928042014-08-25T15:58:40.360-05:002014-08-25T15:58:40.360-05:00VERY interesting case - and I do not know "th...VERY interesting case - and I do not know "the Answer" - but I'll make a couple of comments:<br /><br />After reading the case and before reading comments I wanted to give Adenosine - so I'm glad that treatment worked, even though we don't yet know for sure why it did ...<br /><br />The PR interval in the post-conversion tracing isn't necessarily that short. So I'm wondering how old this "young woman" is (PR intervals tending toward shorter in younger adults). In addition - the post conversion tracing shows sinus rhythm at a rate ~120/minute and PR intervals tend to shorten with tachycardia. There is a lot of artifact - but I measure the PR ~ 0.11-0.12 second (most of it P wave) - which isn't necessarily so "short" if this is a young adult with a rate ~ 120/minute ....<br /><br />I think you still may have a differential between AVNRT vs AVRT (no delta; PR not necessarily short) - though I definitely would not be surprised if this patient had an AP (Accessory Pathway). AVNRT on occasion may attain 260/minute.<br /><br />To my calipers - the rate = 260/minute and is identical for ECG #1 and #2 - which would seem to be too much to be chance .... I'd imagine/expect some short transient break in the rhythm if conduction shifted from orthodromic to antidromic down an AP (but I totally defer to Dr. Wang and others as to whether such immediate shift in direction can occur).<br /><br />As much as the fast rate makes me think about flutter - as you say, you'd then have to explain conversion post-adenosine which is highly unlikely. So my bet is on reentry. I imagine there could be functional/rate-related lbbb aberration vs Steve's theory of changing directions .... I do think the QRS is wide in ECG #2 (despite V4's appearance - the limb leads look quite different - and leads I,aVL and V6 to me look legitimately wide). <br /><br />But after going back-and-forth-and-back again with the above theories in my mind - I just don't know and eagerly await EP results by Dr. Wang.ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-42016777317126915522014-08-25T11:54:07.606-05:002014-08-25T11:54:07.606-05:00The first narrow complex tachy looks like AVRT wit...The first narrow complex tachy looks like AVRT with retro p and St depressions. The wide complex tachy looks like anti dromic tachy but with fast initial component which can be explained if the pathway was atrio fascicular with distal insertion in rbb. However usually such pathways would have decremental properties which is not seen here. Gautamhttps://www.blogger.com/profile/03952480792611560421noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-59814936544384842062014-08-25T09:01:15.155-05:002014-08-25T09:01:15.155-05:00The adenosine terminated it and then it restarted....The adenosine terminated it and then it restarted.Steve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-76893905545493046822014-08-24T23:00:06.508-05:002014-08-24T23:00:06.508-05:00VERY interesting case - and I do not know "th...VERY interesting case - and I do not know "the Answer" - but I'll make a couple of comments:<br /><br />After reading the case and before reading comments I wanted to give Adenosine - so I'm glad that treatment worked, even though we don't yet know for sure why it did ...<br /><br />The PR interval in the post-conversion tracing isn't necessarily that short. So I'm wondering how old this "young woman" is (PR intervals tending toward shorter in younger adults). In addition - the post conversion tracing shows sinus rhythm at a rate ~120/minute and PR intervals tend to shorten with tachycardia. There is a lot of artifact - but I measure the PR ~ 0.11-0.12 second (most of it P wave) - which isn't necessarily so "short" if this is a young adult with a rate ~ 120/minute ....<br /><br />I think you still may have a differential between AVNRT vs AVRT (no delta; PR not necessarily short) - though I definitely would not be surprised if this patient had an AP (Accessory Pathway). AVNRT on occasion may attain 260/minute.<br /><br />To my calipers - the rate = 260/minute and is identical for ECG #1 and #2 - which would seem to be too much to be chance .... I'd imagine/expect some short transient break in the rhythm if conduction shifted from orthodromic to antidromic down an AP (but I totally defer to Dr. Wang and others as to whether such immediate shift in direction can occur).<br /><br />As much as the fast rate makes me think about flutter - as you say, you'd then have to explain conversion post-adenosine which is highly unlikely. So my bet is on reentry. I imagine there could be functional/rate-related lbbb aberration vs Steve's theory of changing directions .... I do think the QRS is wide in ECG #2 (despite V4's appearance - the limb leads look quite different - and leads I,aVL and V6 to me look legitimately wide). <br /><br />But after going back-and-forth-and-back again with the above theories in my mind - I just don't know and eagerly await EP results by Dr. Wang.ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-21875911514101862072014-08-24T22:08:57.661-05:002014-08-24T22:08:57.661-05:00Did the adenosine terminate the initial tach follo...Did the adenosine terminate the initial tach followed by reinitiation or did the axis change mid tachAnonymoushttps://www.blogger.com/profile/07778495688931975375noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-1711040748979897822014-08-24T17:52:08.740-05:002014-08-24T17:52:08.740-05:00Olivier,
It's not a delta wave. If it were, it...Olivier,<br />It's not a delta wave. If it were, it would be registered as a wide QRS. The QRS is only 80 ms.<br />If there were a delta wave, the remainder of the QRS would have to be impossibly short, around 50-60 ms.<br />SteveSteve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-33621742891402048092014-08-24T17:46:45.906-05:002014-08-24T17:46:45.906-05:00It's not a delta wave. If it were, it would b...It's not a delta wave. If it were, it would be registered as a wide QRS. The QRS is only 80 ms.Steve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-56900776894306538642014-08-24T13:47:33.641-05:002014-08-24T13:47:33.641-05:00No delta waves? There is something subtle delta-li...No delta waves? There is something subtle delta-like in V5 and V6, maybe also in V4. It could be seen better at 50 or 100 mm/s.Alexey Rukinhttps://www.blogger.com/profile/10648952895362962043noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-39902287126003165822014-08-24T13:25:25.300-05:002014-08-24T13:25:25.300-05:00are you sure there is no delta wave in the third E...are you sure there is no delta wave in the third ECG (I see one in DII, V3-4-5). The different morphology of the qrs in the 2nd ECG looks like a "superwolf", no?Olivier Peyronyhttps://www.blogger.com/profile/11131579398938096686noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-13579977736247256842014-08-24T12:20:55.011-05:002014-08-24T12:20:55.011-05:00very interesting dr. Smith! Can'T wait to see ...very interesting dr. Smith! Can'T wait to see the results!!Anonymoushttps://www.blogger.com/profile/07220706531456511563noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-67152032223692685242014-08-24T09:15:59.176-05:002014-08-24T09:15:59.176-05:00Abberrancy. AVNRT->adenosine->patient fells ...Abberrancy. AVNRT->adenosine->patient fells bad with more simpatetic activity ->little faster AVNRT with aberrancyAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-50068763575411300322014-08-24T07:43:22.048-05:002014-08-24T07:43:22.048-05:00you might be rght. I'm certainly getting a va...you might be rght. I'm certainly getting a variety of opinions on this.Steve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-79172065713736539162014-08-24T02:11:37.807-05:002014-08-24T02:11:37.807-05:00This is avnrt with slow fast component and should ...This is avnrt with slow fast component and should be treated with calcium channel blocker.Anonymoushttps://www.blogger.com/profile/16218268439781983452noreply@blogger.com