FRANKFORT, Ky. (AP) _ The mystery of Coronary Valley is drawing health experts from around the country.

Of the 12 states with the country's highest death rates from heart disease, nine are along the Ohio or lower Mississippi rivers. Another is New York, on the Hudson River.

Whether that's coincidence, or has some explanation, nobody knows.

Dr. James Muller, director of Gill Heart Institute at the University of Kentucky, arranged a symposium on the issue that begins Thursday in Lexington.

When he arrived from Harvard in 1996, he knew Kentucky had a high heart disease death rate _ fifth highest at 116.7 deaths per 100,000 population.

But when he looked at maps of the distribution of high heart disease rates, ``I noticed that it seemed to go down the Ohio River and down the Mississippi, so I started calling it the Coronary Valley,'' Muller said in an interview.

``I coined the phrase because I think it's something we need to bring attention to, to solve.''

The states that border the Ohio and Mississippi and have high death rates from heart disease are Kentucky, Missouri, Arkansas, West Virginia, Indiana, Tennessee, Louisiana, Ohio and Illinois.

New York, split by the Hudson River, has the highest rate _ 135.9 deaths per 100,000 people, according to the National Center for Health Statistics in Hyattsville, Md.

Oklahoma, whose southern border is formed by the Red River, is second-highest at 120.2. The remaining state in the top dozen is Michigan, 11th at 108.4, which sits between two of the Great Lakes.

Minnesota, at the headwaters of the Mississippi, is among the 12 states with lowest heart disease death rates, at 81.4 per 100,000. The remaining upper Mississippi states _ Wisconsin and Iowa _ are between the two extremes.

Kentucky's state epidemiologist, Dr. Glenn Caldwell, said Coronary Valley probably can be explained by a combination of lifestyle, genetic and environmental factors.

``I spent 20 years studying `cancer clusters,' and you almost never find real cause-and-effect relationships in these clusters,'' Caldwell said.

The state with the lowest heart disease death rate is New Mexico, with 54.2.

Yet, like Kentucky, New Mexico has high rates of obesity and diabetes, two of the most notorious risk factors for heart disease. It also is a rural state that lags in preventive health care because large numbers of people are uninsured.

Dr. Johnathan Abrams, a University of New Mexico cardiologist, said genetics might partly account for that state's low rate. Indigenous Hispanics and American Indians, who together make up about half the state's population, traditionally have extremely low rates of heart disease.

However, ``no one really believes that our lifestyle, diet and exercise are better here,'' Abrams said. ``This is a third world country in many ways.''

Abrams was among those planning to speak at the symposium.

``I'm not going to have an answer,'' he said. ``I'm going to suggest tongue in cheek that it's green chili.''