In the ED, a 16-year-old has an abnormal EKG rhythm. Which diagnosis is most consistent with this finding?

• A. Cardiac arrhythmia
• B. Myocardial infarction
• C. Seizure
• D. Dehydration

Answer: (A)

An abnormal EKG rhythm points to a disturbance in the heart’s electrical system, which is what a cardiac arrhythmia is. The EKG records how fast and how regularly the heart beats, and when that rhythm is off, the most fitting diagnosis is an arrhythmia because the primary issue is the heart’s electrical conduction, not tissue damage or brain activity. In a 16-year-old, a myocardial infarction is unlikely, since heart attacks are rare in teens. Seizures can be associated with autonomic changes, but the heart rhythm abnormality seen on an EKG isn’t best explained as a seizure. Dehydration can cause a fast heartbeat due to volume loss, but it doesn’t typically produce an inherently abnormal rhythm pattern. So, the finding most consistent with an abnormal EKG rhythm is a cardiac arrhythmia.