Another diagnostic ECG of a potentially deadly condition

 Written by Pendell MeyersA middle aged woman with no significant past medical history presented with epigastric abdominal pain with vomiting off and on for the past few days. Today her symptoms returned and intensified, so she came to the Emergency Department. Her vital signs were only significant for mild bradycardia.What do you think? It is basically pathognomonic.Here is her triage ECG:Here is her baseline ECG on file from several months prior:The presentation ECG shows sinus bradycardia with a normal QRS complex followed by diffuse down-sloping ST depression with extremely long down-up T waves. This is diagnostic of hypokalemia, of course with additional potential contributing factors of hypomagnesemia, medications, etc., but the morphology here is (I believe) quite specific for hypokalemia as the most significant single contributor.Notice the fact that this diffuse STD is maximal in V4-V6 and lead II, just as all diffuse, nonfocal STD should be. The computer calculates the heart rate as 52 bpm, and the QT interval as 637 ms.When I measure the QT interval myself, I get approximately 680-690 ms.Notice that the " half the R-R interval " rule of thumb becomes more and more dangerous below 60 bpm. In this case, the QT interval is either just at or just beyond the halfway point, with massively prolonged QT.Also note that one should not even correct the QT interval for heart rates below 60 bpm. See very detailed discussion here for the reasons why in the article...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs