CHICAGO (AP) — Older people who have a thickening of the wall around the heart’s main pumping chamber are nearly three times as likely as people with normal hearts to suffer a stroke, a study found.

The thickening can be detected by echocardiography, but because of the $400 to $500 cost and because the exact relationship between the thickening and strokes is not yet clear, the ultrasound procedure should not be used routinely as a stroke-risk detector, doctors say.

The study is the first to find a link between heart-wall thickening and stroke risk regardless of whether other factors, such as high blood pressure or other heart conditions, are present, said a co-author, Dr. Daniel Levy.

“The heart may be a good barometer of risk throughout the entire cardiovascular system,” said Levy, director of cardiology for the Framingham Heart Study, of which the new findings are part.

The Framingham Heart Study, based in Framingham, Mass., is one of the largest, longest and most influential studies of heart disease and related ailments.

Levy’s team, led by Dr. Mahesh Bikkina, used echocardiography to monitor the hearts of 1,230 men and women ages 59 through 90 for an eight-year period. Echocardiography produces pictures of the heart much like sonar produces pictures of the ocean floor.

During the study, 89 strokes or “mini-strokes” occurred. Strokes were 2.73 times more likely in people with the greatest thickening around the heart’s main pumping chamber than in people with the least thickening.

The finding supports several similar studies, including one the researchers did several years ago, they noted in Wednesday’s issue of the Journal of the American Medical Association.