6-year-old presents with mildly elevated heart rate that is persistent

Case

Hi, thanks for taking my call. I have a 6-year old female who presents today for what appears to be an otitis media on her right ear. Mom says she has had a day of fever and has been complaining of ear pain. The reason I am calling is that when she came into the office, her heart rate was 150 bpm. She had a temperature of 39.5°C at the time, so I thought maybe it was related to the fever. I had the mom give her a dose of acetaminophen and a few hours later had them come back for a heart rate check and it remains at 150 bpm with a normal temperature. I’m honestly not sure what to make of this heart rate. She appears asymptomatic except for her ear but the heart rate worries me. Anything I should do about it?