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Man's 'heart attack' was really side effect from swallowed battery

AA battery on a white background.
(Image credit: Shutterstock)

When a man arrived at the emergency room, it looked to doctors like he was having a heart attack. But that was a false alarm: The man had actually swallowed a battery that messed with his electrocardiogram (EKG), a measure of the heart's electrical activity, according to a new report of the case. 

Once doctors removed the battery, the EKG returned to normal, according to the report, published Monday (Nov. 23) in the journal Annals of Internal Medicine.

"If someone swallows a single battery or multiple batteries, the electrocardiogram can mimic changes consistent with an acute [myocardial infarction, or heart attack]," said Dr. Guy L. Mintz, director of cardiovascular health and lipidology at Northwell Health's Sandra Atlas Bass Heart Hospital in Manhasset, New York, who was not on the case. 

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The 26-year-old man was a prison inmate who arrived at the emergency department of Santa Maria Nuova Hospital in Florence, Italy complaining of stomach pain two hours after intentionally swallowing a AA battery. There, having spotted the battery on an X-ray, doctors did an EKG, in which electrodes placed on the chest record the electrical activity of the heart and graph it as a squiggly line on a gridded background.

The EKG showed a sign of a heart attack known as "ST segment elevation." This means that a particular segment of the EKG which is normally flat is instead elevated, Mintz told Live Science. 

The EKG was the inmate's only sign of heart attack. He had no history of cardiovascular disease and his only risk factor for heart disease was cigarette smoking, according to the report. He did not report symptoms of a heart attack (such as shortness of breath), and his levels of cardiac troponin, heart muscle proteins that are released into the blood during a heart attack, were normal. 

Previous case reports have documented people swallowing batteries and having EKGs with ST elevation, the authors said. For example, this effect has been reported in a man who swallowed six AAA batteries, and another man who swallowed 18 AA batteries. The authors of previous case reports had suggested that perhaps it took more than one battery to alter the EKG. However, this study disproves that hypothesis.

Mintz called the report"interesting niche information."

"[I] doubt [the] majority of clinicians are aware of this phenomenon," Mintz said. He advises doctors treating patients who've swallowed batteries to check for biological markers of heart function (such as troponin levels) before reacting to the abnormal electrocardiogram, and to remove the batteries as soon as possible.

But how could battery ingestion mimic heart attack? The case report suggested that the battery's contact with stomach acid could have produced an electric current that traveled to the heart and affected the EKG. "[This is] not a proven mechanism, but this is a plausible mechanism," Mintz said.

Even though these patients weren't actually having heart attacks, swallowing a battery could still possibly hurt the heart. "Prolonged electrical effects could cause damage to the heart," Mintz said. 

There are, of course, other reasons not to swallow batteries. "Swallowing a battery is dangerous as breakdown can cause chemical leakage or even an intestinal obstruction," Mintz added. 

In the current case, the man had no reported complications from the battery.

Originally published on Live Science.