Jan. 12 (HealthDay News) -- Unexplained chest pain after a heart attack may be more dangerous than doctors initially believe, suggests a case study published in the January issue of the journal Clinical Cardiology.

In the article, doctors at Thomas Jefferson University Hospital in Philadelphia describe the case of a seemingly healthy 55-year-old man who had a silent heart attack and suffered subsequent unexplained chest pain.

Further investigation revealed that the man had a rarely diagnosed complication called subepicardial aneurysm. If not promptly treated, the problem can be fatal.

"The chest pain was a rupture of the heart wall about to happen -- the most feared complication of a heart attack," Dr. Michael Savage, director of the Cardiac Catheterization Laboratory at Thomas Jefferson University Hospital, said in a prepared statement.

"The rupture occurs from a tear in the muscle that has already been damaged by heart attack. The heart muscle breaks, and the wall bursts, usually causing cataclysmic death soon after," Savage said.

When a patient has unexplained pain after a heart attack, doctors should consider the possibility of a subepicardial aneurysm, recommended Savage and his colleagues.

In this case, a CT scan detected the problem. Doctors repaired the man's heart and saved his life.

Subepicardial aneurysm diagnoses are extremely rare, and only 20 have been reported in the medical literature, Savage noted. However, he said it's likely that subepicardial aneurysm is not pinpointed as the cause of death in many patients who die from this condition.