tag:blogger.com,1999:blog-549949223388475481.post4635056970629078394..comments2024-03-26T22:42:04.176-05:00Comments on Dr. Smith's ECG Blog: A woman in her 50s with dyspnea and bradycardiaUnknownnoreply@blogger.comBlogger6125tag:blogger.com,1999:blog-549949223388475481.post-80977465275216945552020-01-27T12:35:21.196-06:002020-01-27T12:35:21.196-06:00THANKS Jerry. Your comments are welcome additions ...THANKS Jerry. Your comments are welcome additions to this post! — :)ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-686347602243068252020-01-27T11:22:12.815-06:002020-01-27T11:22:12.815-06:00Excellent case, Pendell and great comments by Drs....Excellent case, Pendell and great comments by Drs. Grauer and Wang.<br /><br />Here are a few things I've learned throughout my career:<br /><br />1) It doesn't really matter what the rhythm is; the hyperkalemia is going to kill the patient first - not the rhythm.<br /><br />2) Hyperkalemia can kill suddenly and rapidly. I've seen a number of journal articles (usually written by residents) that state you don't need to be concerned about treating the patient until a certain ECG change appears or until the level reaches 7.0. One should be concerned about treating the patient as soon as there is any suggestion on the ECG of an elevated K+. How much time elapsed between the ECG done at triage and the ECG done after the labs had been sent?<br /><br />3) Tall peaked T waves are only seen in about 22% of the ECGs when first recorded. That means that almost 80% of the patients with hyperK+ will NOT have the classic hyperkalemic T waves! In my ECG interpretation classes, students must be able to diagnose (or suspect the presence of) hyperkalemia WITHOUT tall peaked T waves!<br /><br />4) Anytime you can barely see the P waves - check the PR interval! A 1st degree AV block in the presence of P waves that can barely be discerned is NOT necessarily a benign finding. Suspect hyperkalemia!<br /><br />5) (and final!) Look at the QRS complexes in leads V4 - V6 on the initial tracing. Those are rS complexes but here is a subtle finding. Usually, when you have r waves initiating a QRS which are THAT small, they typically appear as a small SOLID upright "blip." Now look at the r waves in those leads again. They, too, are very, very tiny - but you can see daylight between the ascending and descending limb of those miniscule deflections. That represents conduction delay (decreased slope of Phase 0, widening of the QRS) that is present from the very beginning of the deflection. This is not a finding that is specific for hyperK+ but don't fall into the trap of thinking that all findings must have high specificity to be useful. That's why we have brains - to put these things together. Only a high serum potassium level can PROVE hyperkalemia. But we shouldn't wait that long!Jerry W. Jones, MD FACEP FAAEMhttps://www.blogger.com/profile/10333187745825224414noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-57205124530815966412020-01-26T21:12:01.940-06:002020-01-26T21:12:01.940-06:00Thanks K! We both agree — The effect of hyperkalem...Thanks K! We both agree — The effect of hyperkalemia on the ECG is additive to (superimposed on) however the baseline ECG looked! IF the baseline ECG shows ST-T wave inversion — this may attenuate T wave peaking from superimposed hyperkalemia. As I emphasize in my Pearl #8 — it’s impossible to know how much the hyperkalemia is influencing QRS width and ST-T wave morphology until you normalize serum K+ and then REPEAT the ECG. Thanks again for your comment! — :)ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-16921621220962983052020-01-26T21:04:28.427-06:002020-01-26T21:04:28.427-06:00THANK YOU K! I believe you wrote this before I add...THANK YOU K! I believe you wrote this before I added My Comment (which I did just now) — and in which I specifically also commented about sinoventricular rhythm in ECG #1. I thought ECG #3 especially interesting — in that a slightly accelerated ventricular escape rhythm intermittently takes over from this underlying sino-ventricular rhythm. THANKS again for your comment! — :)ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-36510697865295433872020-01-26T12:07:23.420-06:002020-01-26T12:07:23.420-06:00In the tracing #1 above, the P waves are barely vi...In the tracing #1 above, the P waves are barely visible, but they are there, proving that it is a sinus rhythm. What does hyperkalemia do to the P waves? It makes them flatter, flatter and eventually disappear (atrial paralysis) even though the QRSs are still driven by the sinus node impulses. At that point, the rhythm is called sino-ventricular rhythm). This sino-ventricular rhythm proves that there must be a specialized conduction system(s) connecting the sinus node and the ventricular myocardium (an experiment of nature). This specialized conduction system connecting the sinus node and the ventricular myocardium has not been histologically identified yet, not like AV node, left or right bundle branches. <br />K. Wang.Anonymoushttps://www.blogger.com/profile/04509940285330859355noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-46015099422705903392020-01-26T11:01:42.713-06:002020-01-26T11:01:42.713-06:00In hyperkalemia, we always look for tall T waves. ...In hyperkalemia, we always look for tall T waves. But the T waves do not have to be tall. If the base of the T wave comes together to make it narrow, pointed and "tented", we are dealing with hyperkalemia!! Of course, the QRS will be widened by then. The tracing #1 above is a good such an example.<br />K. Wang.<br /><br /><br />Anonymoushttps://www.blogger.com/profile/04509940285330859355noreply@blogger.com