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A man swallowed a battery. Why did it look like he was having a heart attack?

Doctors were surprised that a single AA battery's electrical properties mimicked a heart attack on an electrocardiogram.

A man showed signs of a heart attack after swallowing a battery, doctors reported Monday in the journal Annals of Internal Medicine.

The patient, a 26-year-old inmate in an Italian prison, was taken to the emergency room for stomach pain two hours after deliberately swallowing one AA battery.

An X-ray revealed the object, where it appeared to be stuck in the man’s stomach. The doctors also performed a test called an electrocardiogram, or EKG, which measures the heart’s electrical activity.

Oddly, the EKG pattern was similar to one that’s commonly seen when someone is having a heart attack. However, the man had no other heart attack symptoms, including chest pain, and other test results showed no signs of any heart issues.

Instead, the authors of the report, from two hospitals in Florence, Italy, wrote that the battery — itself a source of electricity — was the source of the EKG pattern, which neatly mimicked what would be seen in a patient having a heart attack.

Indeed, the heart’s electrical activity returned to normal after the battery was removed.

That these EKG readings occurred after ingesting a battery is not surprising — after all, batteries conduct electricity. What made the case striking, the authors wrote, is the man had only swallowed one.

“Previously, these EKG changes were described only in persons who swallowed several batteries,” they wrote.

“Theoretically, if you have more electrical interference” from multiple batteries, you might see more pronounced EKG changes, Dr. Luke Laffin, a cardiologist at the Cleveland Clinic in Ohio, said.

Laffin, who was not involved with the man’s case, said that the battery appeared to be distorting the EKG reading, resulting in what he called a “pseudo infarction pattern.” (An acute myocardial infarction is the medical term for a heart attack, in which blood flow to the heart muscles is cut off, causing tissue damage and death.)

Abnormal EKG readings can alert doctors to heart problems, such as heart attacks or arrhythmias. But in the man's case, a heart problem didn't cause the change in electrical activity picked up by the EKG, the battery simply interfered with the reading, Laffin said.

Because of that, he noted, there wouldn't be any damage to the heart in such a case.

Still, "swallowing batteries is really dangerous — particularly in kids — but there's not really a whole lot of cardiac things that we worry about," Laffin said.

Swallowed batteries can also get stuck somewhere and cause obstruction, or stomach acid could chew through the battery, spilling its dangerous contents into the body.

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