Researchers solve the mystery of why some people have chest pain but no sign of heart trouble

Thursday, June 20th 2002, 12:00 am
By: News On 6

BOSTON (AP) _ Researchers have taken a step toward solving one of modern medicine's mysteries: why so many people get chest pain without classic signs of heart disease.

The simple answer: They have unseen heart disease.

The condition, known as cardiac syndrome X, has befuddled doctors since it was identified about 30 years ago. For all its mystery, it is widespread, striking perhaps tens of thousands of Americans, mostly women.

Many doctors have long viewed it as an unexplained form of heart disease. But others see it a puzzling hypersensitivity to pain _ that is, a neurological problem, not a cardiovascular one.

The latest research, published Thursday in The New England Journal of Medicine, blames syndrome X on irregular blood flow in microscopic arteries within the heart wall.

However, there is no evidence that the blood-flow problem raises patients' risk of a heart attack or other deadly heart trouble, the researchers said.

Syndrome X patients suffer from angina, the common chest pain of heart disease. Their hearts also show abnormalities during exercise testing on a treadmill. But there is no apparent reason for the pain. X-ray angiogram tests fail to show the blocked blood vessels that choke off blood flow to the heart in typical angina patients.

Syndrome X itself is not life-threatening. However, some doctors, in an effort to ease the chest pain, treat syndrome X with the same beta blocker drugs given to other heart patients. Too often, they do not work.

The scientists conducted the new research at a London hospital, performing magnetic resonance imaging on 20 syndrome X patients and 10 healthy ones. Electromagnetic MRI scans, which yield 3-D images, can show blood flow in finer detail than angiograms.

The images showed poor distribution of blood flow in the syndrome X patients: too little in the inner heart wall and too much in the outer layer.

The tests suggest poor blood movement within tiny heart arteries, whether from a biochemical signaling failure, minute spasms or similar causes, according to chief scientist Dr. Dudley Pennell of Royal Brompton Hospital.

Dr. Julio Panza of Washington Hospital Center in Washington, D.C., said in an accompanying article that the research adds to evidence that syndrome X is a heart disease.

But he said the drug adenosine, which was given to the patients to simulate the stress of exercise, could have caused the effect seen on MRIs.