The Littmann sign: An indication of hyperkalemia

Computer-Estimated Heart Rate vs True Heart Rate—Be Aware of the Software

“…In severely ill patients, heart rate overcounting by computerized software, especially in combination with wide QRS complexes, is a strong indication of possible severe hyperkalemia. [1][2][3]…”

“…9 Recently, it was found that overcounting of the heart rate by ECG interpretation software, especially when combined with wide QRS complexes, can also be an indication of severe hyperkalemia. [1][2][3] The cause of hyperkalemic heart rate double counting is uncertain, but it is most likely due to software not being able to distinguish between widened QRS complexes and tall T waves. The present case strongly supports this hypothesis because during cardiac arrest, both the QRS complexes and the T waves were marked as ventricular complexes (Figure , B).…”

“…Double counting of the heart rate has been seen with different ECG systems using a variety of computer algorithms. [1][2][3] Overcounting of the heart rate is not fully specific for the diagnosis of hyperkalemia given that pacemaker spikes, artifact, tall P waves, and physiologically tall T waves too can be mistaken for QRS complexes. However, in a severely ill patient, heart rate overcounting, especially when combined with QRS complex widening, should prompt consideration of severe hyperkalemia.…”

“…Wide QRS complex pulseless electrical activity and nonshockable regular wide-complex tachycardia are frequently indicators of extreme hyperkalemia and should prompt immediate treatment with intravenous calcium . Recently, it was found that overcounting of the heart rate by ECG interpretation software, especially when combined with wide QRS complexes, can also be an indication of severe hyperkalemia …”

ECG artefacts in emergency medicine

“…Previsoko postavljene elektrode V1-V2 manifestuju se elevacijom ST segmenta, koja se gubi stavljanjem elektroda na pravilno mesto Picture 9: High placement of V1 and V2 electrodes produces ST elevation which disappears after correction EKG aparat može da napravi grešku pri određivanju frekvence srca kada su T talasi toliko visoki da ih pogrešno prepoznaje kao R zupce i zato računa frekvencu duplo. Ta greška se naziva Litmanov znak (slika 10) i veoma j.e sugestivna za hiperkalemiju [16,17]. I drugi elektroliti disbalansi mogu u toj meri da izmene osnovne elemente EKG-a, da dovode do pogrešnog računanja od strane EKG mašine.…”