(CNN) A 9-year-old boy who was enjoying a hot dog took an overly big bite -- and went into cardiac arrest. But choking wasn't the cause, according to a case study published Wednesday in the journal Pediatrics.

The terrifying incident had a much more unlikely cause, according to Dr. Isa Ozyilmaz of Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Training and Research Hospital in Istanbul.

The chunk of frankfurter stimulated the boy's vagus nerve, and this triggered an abnormal heart rhythm that in turn caused his heart to abruptly stop beating, Ozyilmaz and his co-authors speculated in the case study. The nerve, which extends from the head to the abdomen, helps the heart and gastrointestinal system function.

Despite immediate panic, the story has a happy ending: After defibrillation, the child was resuscitated.

Oddly, the boy's family history appeared to be a clean slate with regard to special cardiac diseases. However, doctors discovered a suspicious finding on his electrocardiograph (known as an ECG or EKG) during a followup examination.

With a possible diagnosis in mind, doctors at the Istanbul hospital conducted an ajmaline challenge test, which involves injecting the child with an antiarrhythmic drug and then observing how his heart responds. The pattern appearing on the EKG verified the diagnosis, and their verdict was swift: The boy had Brugada syndrome.

What is Brugada syndrome?

"Brugada syndrome is an inherited (heart) rhythm problem," said Dr. Anne Dubin, a professor of pediatric cardiology at Lucile Packard Children's Hospital Stanford, who was not involved in the boy's case.

The syndrome takes its name from Dr. Pedro Brugada of QLV Hospital in Aalst, Belgium, and his brother Dr. Josep Brugada of the Hospital Clinic at University of Barcelona in Spain, who first described it in a study published in 1992 . (A third brother, Dr. Ramon Brugada of Montreal Heart Institute and University of Montreal helped unravel the genetic basis.)

The total number of cases is difficult to measure, because some people may be asymptomatic or have never been tested thoroughly. Based purely on EKG findings, about four in 1,000 Americans have been diagnosed with Brugada syndrome , according to Stanford Center for Inherited Cardiovascular Disease.

The essence of the problem is not mechanical, but electrical. Thinking of the heart as an electric pump, the problem "can lead to abnormal heart rhythms in the lower chambers of the heart that can be associated with sudden death," Dubin said.

"What allows the electrical signal to move through your heart are a series of channels within the heart cells themselves," she said. "Different salt ions, like sodium or potassium or calcium, move through those channels and change the electrical current within the cell, and that's what moves the electrical signal through the heart."

One known cause of the syndrome is a deficiency of sodium, which has an impact on the electrical current moving through these channels. When patients with Brugada syndrome eat large bites of food -- which is known to stimulate the vagus nerve -- changes in EKG patterns also occur, and this may lead to sudden cardiac arrest, according to Ozyilmaz and his co-authors.

The condition is found in more men than women, according to the Stanford center. It is also more commonly found among people of Asian descent, although anyone can be affected.

Because Brugada syndrome runs in families, the 9-year-old's doctors immediately tested his family and discovered that his brother also has the condition.

Genetic test results for both parents are pending, according to the study, but Dubin said that "odds are good that one of the parents has this. Sometimes, you don't really see it until you do the challenge test."

Another way to diagnose the syndrome is through genetic testing, but only about 30% to 40% of the genes that cause it are known, Dubin said. People with symptoms don't require such tests; instead, doctors use the results of DNA testing to figure out which family members may have the syndrome even if they show no signs of illness.

A very rare condition

Many people do not even know they have the condition until later in life.

The majority of people who develop symptoms of Brugada syndrome are already "in their 20s up to 50s or 60s," Dubin said.

When the condition is discovered in parents, doctors will screen the children, even those without symptoms, and may discover it then. "And then you have to decide what to do with them," said Dubin.

"As far as symptomatic Brugada syndrome, I have been practicing pediatric electrophysiology for 23 years now, and I have probably seen two to three cases of it," she said.

The story of the boy with the hot dog, then, is extremely rare.

After the incident, the boy's doctors implanted a defibrillator in his chest to prevent sudden cardiac arrest, the case report noted.

"Defibrillators in kids are associated with higher risks than in adults, for sure," Dubin said. "But sometimes we need to do it." She added that "there isn't a whole lot we can do for people, and the primary way we treat them is with a defibrillator."

"People shouldn't panic about Brugada syndrome," she said. "If you have a family history of people dying suddenly with no known reason or if you have someone in your family who has been diagnosed with Brugada syndrome as an adult, children need to be evaluated for it, and we need to know about it." But there's no need to routinely screen children, she said.

Still, when children of people with the illness are screened and found to have the condition, "even if there is no golden bullet" for treatment, the information is still vital for parents. Commonly they will be advised "to be very careful about fever prevention, and there are certain drugs they should stay away from" when treating their children for other illnesses.

Join the conversation See the latest news and share your comments with CNN Health on Facebook and Twitter.

Information from the case report will not apply to most children, said Dr. Elizabeth Saarel, chair of pediatric cardiology at Cleveland Clinic Children's Hospital and a spokeswoman for the American Academy of Pediatrics. Still, the syndrome is "rare but life-threatening," so parents need to be aware, she suggested.

"Kids choke on hot dogs and food all the time and sometimes go into cardiac arrest," said Saarel, who was not involved in the new case report. "Pediatricians assume this is always an airway issue. This case report indicates that children who choke on food and go into cardiac arrest also need to be screened for Brugada syndrome."

Correction: A previous version of this story gave an incorrect title for Dr. Anne Dubin.