Worldwide, almost as many women as men die from heart disease.Yet most treatment methods have come from studies of men.Researchers are now learning more about ways that heart disease can be different in women.

For example, they say a condition called coronary microvascular syndrome appears to be more common in women than men.

When a heart attack is suspected, doctors look for a major blockage in the arteries that supply oxygen to the heart.With coronary microvascular syndrome, fatty material spreads evenly in very small arteries of the heart.This buildup of plaque along the artery wall narrows the flow of oxygen.The pain can be similar to that of blocked arteries.

But doctors often miss this condition because it does not show up in the usual tests for blockages.Women are often sent home, thinking they are OK.Yet many are at high risk for a heart attack.

In the United States, researchers say as many as three million women could have coronary microvascular syndrome.The Journal of the American College of Cardiology recently published findings from a government study.

The study is called the Women's Ischemia Syndrome Evaluation, or WISE.Ischemic heart disease involves restricted blood flow.The study began in nineteen ninety-six and involves more than nine hundred women who suffer chest pain.

Researchers found large blockages in major arteries in about one-third of the women.The other women looked clear on an angiogram test for blockages.But the researchers say half of them had enough buildup in small arteries to cause a heart attack within five years.

Scientists have been trying to better understand why heart disease is often discovered later, and treated less aggressively, in women.Women are also less likely to react as well as men to treatment.

Experts note that women are generally older than men when they have a heart attack.The National Heart, Lung and Blood Institute says women are also less likely to believe they are having a heart attack.So they are more likely to delay emergency treatment.

In men and women both, the most common warning sign is chest pain.But women are more likely to experience other common signs like shortness of breath, a sick stomach and pain in the back or jaw.A cold sweat and feeling lightheaded can also mean a heart attack.

This VOA Special English Health Report was written by Cynthia Kirk, and can be found at WWW.51VOA.COM.I'm Steve Ember.