A young man with back spasms

Written by Pendell Meyers with edits by Steve SmithFirst see this ECG without clinical context:What do you see? Do you agree with the computer ' s read of " nonspecific ST abnormality? "The ECG is highly suspicious for hypokalemia. There is diffuse minimal STD, with prolonged QT interval and characteristic " down-up " T-wave morphology in the precordial leads which is being caused by U-waves. V2 has an especially pronounced U-wave, but there is also a slightly wandering baseline. This morphology is very unlikely to be due to ischemia, and to an experienced electrocardiographer is nearly pathognomonic of hypokalemia +/- other concomitant factors such as hypomagnesemia, medication-induced long QT, etc.Now here is the clinical scenario:A young male in his 20s presented with back pain which he described as " back spasms " and weakness worsening all week and which became severe yesterday after lifting some boxes. Only upon review of his chart, I became aware that he had a history of CKD and eating disorder resulting in extreme electrolyte disturbances.So I ordered this ECG:We diagnosed hypokalemia based on the ECG and history. The computer read the QT and QTc intervals as 449ms and 488ms, respectively.Do you agree?No!Because of the prominent U-wave merging with the end of the T-wave, it is almost impossible to measure the QT interval, so let ' s measure the QU interval:It is difficult, or even impossible, to determine the end of the T-wave because of a prominent U-wave. You c...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs