tag:blogger.com,1999:blog-549949223388475481.post1102404362791692632..comments2024-03-28T14:02:08.119-05:00Comments on Dr. Smith's ECG Blog: Wide complex tachycardias: 2 cases. What is the diagnosis and management?Unknownnoreply@blogger.comBlogger28125tag:blogger.com,1999:blog-549949223388475481.post-41019148189395816622019-01-16T15:57:34.235-06:002019-01-16T15:57:34.235-06:00No. The RR interval will always be a multiple of a...No. The RR interval will always be a multiple of a whole number. That whole number is the flutter interval.Steve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-35638649833005194312019-01-16T13:02:03.441-06:002019-01-16T13:02:03.441-06:00Sir, Wouldnt atrial flutter with variable block al...Sir, Wouldnt atrial flutter with variable block also be irregularly irregular?tsbqb11https://www.blogger.com/profile/04429574676726934889noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-16130087904218665582016-12-29T05:29:54.405-06:002016-12-29T05:29:54.405-06:00Adenosine is safe in flutter 2:1. It is only unsa...Adenosine is safe in flutter 2:1. It is only unsafe in atrial fib. so you can give adenosine if the rate is perfectly regular.Steve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-90870941530306834852016-12-26T16:52:47.789-06:002016-12-26T16:52:47.789-06:00Hi Dr. Smith,
Is it possible to have someone in a...Hi Dr. Smith,<br /><br />Is it possible to have someone in a flutter/a fib with an underlying accessory pathway that is not being used? The reason I ask is because it is tough (?impossible) to differentiate a flutter 2:1 with ventricular response of 150 from orthodromic AVRT/AVNRT at 150 with an ECG, so whenever I see a regular narrow complex tachycardia at a constant 150 I cardiovert instead of giving adenosine. However, if they are hemodynamically stable and talking to me, is it 100% safe to give the adenosine, even if it is flutter 2:1? Some people use this adenosine "challenge" to clarify what is going on, and I just want to know if this really is completely safe. <br /><br />Thanks a lotNeilhttps://www.blogger.com/profile/15897507184085677155noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-30660671509918767252014-01-21T22:24:10.023-06:002014-01-21T22:24:10.023-06:00It's almost been 2 years since this post, so f...It's almost been 2 years since this post, so forgive my late arrival to the discussion. A study done in 1997 showed that about 12% of the patients who received adenosine for PSVT developed atrial fibrillation or atrial flutter in the immediate post-drug period. Both patients with AVRT and AVNRT were susceptible. <br /><br />Adenosine-induced atrial arrhythmia: a prospective analysis.<br />http://www.ncbi.nlm.nih.gov/pubmed/9312997<br /><br />I've been going over adenosine and WCT, provoked by some questions from my residents, and this post came up - very useful!Brooks Walshhttps://www.blogger.com/profile/16108633682893762401noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-30972416554667725522013-03-25T18:08:31.711-05:002013-03-25T18:08:31.711-05:00Did you mean to ask (two words confused me and I c...Did you mean to ask (two words confused me and I changed them): "So could i say that AVRT in the setting of WPW is the same as antidromic conduction of WPW?"<br /><br />Not exactly, because orthodromic AVRT is also due to WPW.Steve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-13110313095560874442013-03-25T11:13:30.628-05:002013-03-25T11:13:30.628-05:00So could i say AVRT in the setting of WPW as the s...So could i say AVRT in the setting of WPW as the same of antidromic conduction of WPW?Ryanhttps://www.blogger.com/profile/07887913972435356137noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-14959820228813310742013-03-23T15:54:49.729-05:002013-03-23T15:54:49.729-05:00Ryan,
AVRT is a type of arrhythmia that can be se...Ryan,<br /><br />AVRT is a type of arrhythmia that can be seen in WPW. It uses both the AV node and an accessory pathway, and goes either down the AV node and up the accessory (orthodromic) or down the accessory and up the AV node (antidromic - this is the wide one). WPW is a syndrome with an accessory pathway (a "Bundle of Kent" which is a bridge of myocardium across the otherwise insulating barrier between atria and ventricles). <br /><br />There are other syndromes which MAY cause AVRT: these would be Lown-Ganong-Levine syndrome and also EAVNC, or enhanced atrioventricular nodal conduction. I don't know much about these latter and they don't seem to have a lot of clinical significance.<br /><br />In other words, WPW does not = AVRT but is the underlying disease state of most AVRT.<br /><br />As for the second part of your question: adenosine can be given for AVRT (a regular tachycardia) but not for Atrial fib in WPW (an irregular tachycardia). In AVRT there is no focus: rather, there is an endless loop going from ventricle up through AV node to atrium then down through bypass tract to ventricle etc. If you just stop the loop at the AV node with adenosine, you stop it and let the sinus node take over.<br /><br />Steve SmithSteve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-13961241063178171882013-03-23T13:17:04.095-05:002013-03-23T13:17:04.095-05:00Come across this post when reading your latest one...Come across this post when reading your latest one.<br />I have a question. Is WPW = AVRT ? I did some google search and it said that AVRT results in pre-excitation similar to WPW. So are they the same?<br /><br />And are you saying that if AVRT is present, yes adenosine can be given but when Afib happens in the setting of WPW, adenosine cannot be given. And the reason being that in Afib there is multiple foci while in AVRT there is only one atrial focus?<br /><br />Am I right?Ryanhttps://www.blogger.com/profile/07887913972435356137noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-34825002861177677212012-03-21T08:10:42.181-05:002012-03-21T08:10:42.181-05:00Maybe you have verapamil sensitive fascicular VT?
...Maybe you have verapamil sensitive fascicular VT?<br /><br />See this link:<br /><br />http://hqmeded-ecg.blogspot.com/search/label/fascicular%20VT<br /><br />Steve SmithSteve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-68284999174330439242012-03-20T18:28:08.146-05:002012-03-20T18:28:08.146-05:00I am an emergency physician who also happens to ge...I am an emergency physician who also happens to get SVTs !<br />I wanted to share some peculiar aspects about my SVT.<br />Since childhood, all my SVT episodes have been succesfully terminated using iv verapamil. However, couple of years ago, when I got an SVT after nearly a decade, the doctor decided to use adenosine which I had never had before. The first 6 mg dose had no effect other than bringing on the well known "impending doom" sensation. The second 12 mg dose did the following.<br />1. HR increased from 190 to 240 !<br />2. Few seconds later, narrow complexes changed to broad complexes.<br />3. Few more seconds later, rythm changed to irregularly irregular ( AF).<br /><br />I remained conscious throughtout and fortunately, the AF lasted only for a few seconds before the original SVT rythm returned, again at 240 bpm.<br />I then quietly asked for verapmil which did the job as usual.<br /><br />During a subsequent SVT episode, somehow, we decided to give adenosine another go in presence of a cardiologist and same sequence again ! Again, verapamil to the rescue.<br />I have AVRT with a left atrial lateral wall accessory pathway that has eluded the ablation catheter probe thrice.<br />I am still at a loss to explain this. Any thoughts ?Torquehttps://www.blogger.com/profile/12839259118453961613noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-67071622574546865292011-07-09T15:31:18.030-05:002011-07-09T15:31:18.030-05:00Adenosine would be completely gone by 90 seconds, ...Adenosine would be completely gone by 90 seconds, so it is hard to see how this is anything other than coincidence. Sounds like he died of an MI, not of any complication of adenosine.Steve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-75877746602288994732011-07-09T15:25:19.056-05:002011-07-09T15:25:19.056-05:00Interesting cases - thank you.
We had a case of a...Interesting cases - thank you.<br /><br />We had a case of an 80 year old male presenting with probable VT (no clear AV dissociation/fusion etc), BP 130/70 and minor chest discomfort (presented 12 hours after onset). We prepped for cardioversion and tried adenosine 6mg and then 12 mg. There was no response to either (clinically or on ECG) Approximately 90 secs after the 12mg (while we finalized for the DC cardioversion) he arrested. Immediate cardioversion restored NSR at 60 with ischemic tombstone ST segments. Despite aggressive ACLS including tenecteplase in PEA, we were unable to get a ROSC.<br /><br />Coincidence seems unlikely. Comments re: timing with adenosine appreciated.EmergGuyhttps://www.blogger.com/profile/05060081452378065159noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-61468914228175868282011-05-25T08:49:39.732-05:002011-05-25T08:49:39.732-05:00You may well be correct about that!You may well be correct about that!Steve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-69854169741862337722011-05-24T21:06:08.185-05:002011-05-24T21:06:08.185-05:00I think there are negative p waves in the first EC...I think there are negative p waves in the first ECG (best visible in lead III), which makes AVRT most likely dx.zgshttps://www.blogger.com/profile/11500078590231183558noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-33800363221764781382011-05-18T13:04:32.313-05:002011-05-18T13:04:32.313-05:00Great cases! I like the way they are presented, w...Great cases! I like the way they are presented, with the cases followed by the answers/discussion below.Anonymoushttps://www.blogger.com/profile/10900423767859353173noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-78549803073486885322011-05-12T14:06:27.749-05:002011-05-12T14:06:27.749-05:00There is no difference between blocking retrograde...There is no difference between blocking retrograde and anterograde conduction. They are exactly the same physiology. This is also something that would not require a study to confirm.Steve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-2537113157531636792011-05-12T13:19:38.317-05:002011-05-12T13:19:38.317-05:00Dr. Smith,
I have seen variable literature on the...Dr. Smith,<br /><br />I have seen variable literature on the effectiveness of adenosine to block retrograde conduction. The search is made more difficult by the fact that a majority of the literature is on AVNRT rather than AVRT. Is adenosine effective on blocking retrograde conduction?<br /><br />thanks,<br />ScottScotthttps://www.blogger.com/profile/16364641167495330687noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-11709469392476249722011-05-10T08:50:45.113-05:002011-05-10T08:50:45.113-05:00I see. Good pointI see. Good pointSteve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-52671841623201943932011-05-10T08:44:35.438-05:002011-05-10T08:44:35.438-05:00i just mean that the "proof" the saying ...i just mean that the "proof" the saying refers to is the standard treatment for ART, and the saying inherently has lost some of its very rigid meaning. in the past, if we strictly adhere to that saying, adenosine would not even be considered in stable WCT since it's assumed to be VT, and, in a sense, using adenosine to differentiate SVT from VT would mean not assuming the WCT to be VT in the first place.<br /><br />instead, past practices would assume the WCT is VT, and we'd give something other than adenosine. of course, if it didn't work, then what? maybe it's not VT? should we try something else? like adenosine? it's basically the opposite case.<br /><br />i'm just thinking silly thoughts. perhaps i'm just splitting hairs.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-85607317581348210372011-05-10T08:17:57.111-05:002011-05-10T08:17:57.111-05:00I haven't read it in a while, but as I remembe...I haven't read it in a while, but as I remember, it doesn't contradict that. Nor does it support that saying. Because that's not, as I remember, what the paper was about; it was not an epidemiologic study nor purport be. Rather (again, as I remember it) it says what it tries to say: that even if it is VT, adenosine is safe.Steve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-11414124825324283762011-05-10T02:40:24.387-05:002011-05-10T02:40:24.387-05:00hmm, in some ways, doesn't the marill paper pu...hmm, in some ways, doesn't the marill paper put a dent in the oft-heard saying "wide and fast is VT until proven otherwise"?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-33989816614761965372011-05-09T19:25:06.367-05:002011-05-09T19:25:06.367-05:00You are absolutely right about the amiodarone. I ...You are absolutely right about the amiodarone. I meant to remove that but forgot. Thanks. <br /><br />Adenosine only works for "adenosine sensitive v tach" that comes from the right ventricular outflow tract. It is always in a structurally normal heart. It is also very rare, and does not look like typical v tach. If the adenosine works, and the patient has a structurally normal heart, it wasn't adenosine sensitive v tach. <br /><br />The patient can of course also undergo an EP study before ever getting an AICD.<br /><br />See this article: http://circ.ahajournals.org/cgi/content/abstract/96/4/1192Steve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-74844859901516299672011-05-09T18:53:00.669-05:002011-05-09T18:53:00.669-05:00Amiodarone does have AV nodal blocking properties,...Amiodarone does have AV nodal blocking properties, so I believe it is also contraindicated in Afib with WPW. <br /><br />http://www.cjem-online.ca/v7/n4/p262<br />http://www.hrsonline.org/education/selfstudy/articles/shrbel.cfm<br /><br />I also agree with Amal Mattu's concerns with using Adenosine: occasionally adenosine works for VT in the literature. If it works, then what? Now cardiology isn't sure what to do with the patient: was it VT? Do they need an AICD?Grahamhttps://www.blogger.com/profile/00671972982939812253noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-50154203454730614452011-05-09T18:51:12.286-05:002011-05-09T18:51:12.286-05:00ExactlyExactlySteve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.com