It sounds like something from Grey's Anatomy, but it happened in real life.
In 2010, Dr Cheng-Huai Ryu, then an internal medicine intern in Queens, New York, published an unusual medical case after a 29-year-old patient's atrial fibrillation (AFib) unexpectedly resolved during a routine hospital examination.
More than 15 years later, Ryu, now Chief Executive Officer of the Texas Center for Lifestyle Medicine, has shared the story behind the now-viral case, explaining what happened and why it continues to fascinate both doctors and social media users.
The case began when a 29-year-old man arrived at hospital after developing persistent heart palpitations while walking home.
Doctors recorded a heart rate of about 140 beats per minute, well above the normal resting range. An electrocardiogram (ECG) confirmed atrial fibrillation, a condition in which the heart beats irregularly and often rapidly. Although AFib is common, it is relatively uncommon in an otherwise healthy 29-year-old.
Because the cause of the arrhythmia was initially unclear, doctors began preparing for cardioversion, a procedure that restores a normal heart rhythm using a controlled electrical shock if required.
Speaking in a recent Instagram video, Ryu recalled that he was assigned to perform a rectal examination after jokingly losing a game of rock-paper-scissors to another intern.
According to Ryu, the examination was performed to check for hidden blood in the stool before the patient received anticoagulant medication, which can increase the risk of bleeding.
At the same time, the patient performed a Valsalva manoeuvre, a breathing technique in which a person bears down while exhaling against a closed airway.
Moments later, the charge nurse noticed something unusual.
The patient's heart rhythm had spontaneously converted from atrial fibrillation back to a normal sinus rhythm. His heart rate fell from roughly 140 beats per minute to around 80, and follow-up monitoring confirmed the normal rhythm remained stable, eliminating the immediate need for cardioversion.
Encouraged by senior cardiologists and department heads, Ryu later published the unusual case in a peer-reviewed medical journal in 2010.
Doctors believe the most likely explanation is stimulation of the vagus nerve, which helps regulate heart rate through the autonomic nervous system.
Activating the vagus nerve can slow electrical conduction in the heart and, in some cases, terminate certain abnormal heart rhythms. The Valsalva manoeuvre is already used clinically to produce this effect in selected patients with rapid heart rhythms.
In the published case, Ryu concluded that the combination of the rectal examination and the Valsalva manoeuvre most likely produced sufficient vagal stimulation to restore the patient's normal heart rhythm.