A man in his 60s with a seemingly mechanical fall and subsequent seizure. Until the ECG.

Written by Pendell MeyersA man in his 60s is brought in to the ED by EMS for a fall witnessed by his wife, followed by multiple episodes of seizure like activity. Initially the history sounded like a mechanical fall. EMS reported normal vitals with the exception of " periods of bradycardia. " The patient received multiple doses of benzodiazepines for possible seizure activity and arrived altered at the ED. He was intubated soon after arrival for airway protection in the setting of multiple seizure like episodes and very depressed mental status.Here is his initial ED ECG:What do you think?Initially this ECG was misread as atrial fibrillation.Instead, it is sinus tachycardia at approximately 100 bpm with second degree type 1 (wenckebach) AV block. Atrial fibrillation results in an irregularly irregular rhythm, whereas this rhythm is regularly irregular, displaying " grouped beating " in which the QRS complexes come in groups of three.Pearl: any regularly irregular rhythm started as a regular rhythm, but then encountered either dropped (AV blocks) or added beats (PACs, PJCs, PVCs).I do not see any evidence of OMI or hyperkalemia, both of which are very important causes of bradycardia to be identified on the ECG.AV block was not initially noticed, and the history and potential seizure activity caused team to focus on neuroimaging and seizure workup.Some time later, the doctor was called emergently to the bedside for a " change in the monitor " , and this ECG was recorded:Not...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs