A woman in her 50s with dyspnea and bradycardia

Written by Pendell MeyersA patient in her 50s presented with shortness of breath and fatigue worsening over 1 week. Her vital signs were within normal limits except for bradycardia at 55 bpm.Here is her ECG recorded at triage:What do you think?It is probably sinus bradycardia with very small/depressed P-waves and prolonged PR interval. The QRS is about 150 ms, and has morphology consistent with LAFB. The T-waves are peaked. All findings are concerning for hyperkalemia. Here was the baseline ECG on file:The hyperkalemia was not yet identified, and the chemistry was pending.To us, this is clearly hyperkalemia, and we only present what should be an obvious diagnosis because people continue to miss this.  Repetition. Repetition. Repetition.Another ECG was recorded when a " change in the monitor " was noted:The first half of the ECG is the same as above, but the second half shows a suddenly wider QRS complex with RBBB morphology. This likely represents an escape rhythm (possibly originating in the LBB). The QRS width of the RBBB beats is just over 200 msec. This is far too wide for normal RBBB, and also implies hyperkalemia or other QRS widening disturbance. The T-waves are markedly hyperacute.The potassium level came back at 7.8 mEq/L.The patient was treated for hyperkalemia and this was the repeat ECG:Much improved, narrower QRS.The patient did well.Learning Points:Always consider hyperK with slow, wide QRS complexes, among other patterns.It is extremely rare for RBBB ...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs