Hiccups can mean many things to many people.  Maybe you've had too much to drink, eaten something a bit too spicy or just can't catch your breath. But one man's hiccups served as a rare, important signal: He was having a heart attack.

A 68-year-old man came to the emergency room at St. Luke's-Roosevelt Hospital in New York City, telling doctors that he had been hiccupping for four days straight. The man was diabetic, a smoker and had high blood pressure, but doctors could find no signs of what might be causing his hiccups.

The medical team began to try to think outside the box, Dr. Josh Davenport, who treated the man in the emergency room, told ABC News. They gave the man a chest X-ray to look for a tumor in his lungs.

"Sometimes cancer can irritate the nerves running along the heart and diaphragm," the muscle beneath the lungs that contracts forcefully and causes hiccups, Davenport said.

But the chest X-ray was normal. So doctors gave the man some muscle relaxers and sent him home.

"He had no other symptoms - no chest pain, no trouble breathing, no sweating or weakness, nothing like that. So we weren't really concerned," Davenport said.

Two days later, the man came back to the emergency room still hiccupping. One doctor, remembering a rare case from long ago of hiccups associated with heart attacks, recommended giving the man an electrocardiogram to check his heart.

Bingo. The rhythm of the patient's heart beats were abnormal and other lab tests showed that his blood had high levels of a protein that the heart's cells release when they have been damaged.

"That's how we determined he was having a heart attack," Davenport said.

Doctors gave the patient drugs to treat the heart attack and soon after, his hiccups were gone. He was treated and released from the hospital.

Davenport, who wrote a report on the case published in the American Journal of Emergency Medicine, emphasized that this case is extremely rare. Hiccups are almost never a sign of a heart attack, cancer or any other medical problem.

According to the Mayo Clinic, hiccups usually come from eating too much, drinking carbonated beverages or too much alcohol, excitement or emotional stress. Longer lasting hiccups may start because of laryngitis, acid reflux or a tumor in the neck.

Scientists still don't know exactly why we hiccup, and unfortunately, no scientific answer exists for the best way to get rid of them.

"Usually, it's just something that has to go away on its own," Davenport said.