The patient: A 29-year-old man in Queens, New York

The symptoms: As the man was walking home one night, he suddenly started feeling heart palpitations — accelerated heartbeats at irregular intervals — that alarmed him, prompting an immediate visit to the emergency room.

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Medication usually restores the heart's normal rhythm within hours — but in this case, the rectal exam achieved a similar result instantly.

Notably, during the rectal exam, the patient was instructed to bear down and strain without exhaling, a technique called the "Valsalva maneuver." It's also used to clear pressure from the middle ear and is known to increase activity in the vagus nerve.

Stimulation of the vagus nerve is known to increase activity in the parasympathetic nervous system and slow electricity conduction in heart tissue, the patient's doctor wrote in the report. In this patient, stimulation of his vagus nerve likely counteracted the signals causing the arrhythmia, the doctor suspected.

This type of rectal procedure could be an additional method for treating some patients with AFib, the author concluded, though he added that it should not replace more traditional treatments. More research would be needed to justify adding the procedure to standard practice.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

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Mindy Weisberger is a science journalist and author of "Rise of the Zombie Bugs: The Surprising Science of Parasitic Mind-Control" (Hopkins Press). She formerly edited for Scholastic and was a channel editor and senior writer for Live Science. She has reported on general science, covering climate change, paleontology, biology and space. Mindy studied film at Columbia University; prior to LS, she produced, wrote and directed media for the American Museum of Natural History in NYC. Her videos about dinosaurs, astrophysics, biodiversity and evolution appear in museums and science centers worldwide, earning awards such as the CINE Golden Eagle and the Communicator Award of Excellence. Her writing has also appeared in Scientific American, The Washington Post, How It Works Magazine and CNN.