CHICAGO – Hundreds of hospitals around the country are joining the most ambitious project ever undertaken to give faster emergency room care to people suffering major heart attacks.

Fewer than one-third of such patients now get their blocked arteries reopened within 90 minutes of arrival, as guidelines recommend. The risk of dying goes up 42 percent if care is delayed even half an hour longer.

“There’s a very, very large opportunity here to improve patient care,” said Dr. John Brush, a Norfolk, Va., heart specialist who helped the American College of Cardiology design the new project, which is to be launched Monday at an American Heart Association conference in Chicago.

Jim Kern, 47, of Norfolk, experienced both extremes. When he had his first heart attack on Aug. 22, he endured excruciating pain while filling out mundane paperwork and waiting as triage nurses changed shifts. It took nearly four hours to get proper care.

When he had a second attack on Oct. 30 – after the hospital adopted new rapid-care measures – doctors “were there within 15 minutes of the time I hit the door and were already starting to do the prep,” Kern said. “The attention and everything I was given was a difference of day and night.”

Major medical groups and government agencies have endorsed the project, including the National Heart, Lung and Blood Institute, whose director, Dr. Elizabeth Nabel, called it the biggest heart care initiative since paramedics were trained to do CPR in the early 1990s.

It targets heart attacks caused by a total or near-total blockage of a major artery that prevents enough oxygen from reaching the heart tissue. About a third of the 865,000 heart attacks in the United States each year and 10 million worldwide are of this type.

The preferred remedy is angioplasty, in which doctors snake a tube through a blood vessel in the groin to the blockage. A tiny balloon is inflated to flatten the crud, and a mesh scaffold called a stent usually is placed to prop the artery open.

Guidelines have long called for a “door-to-balloon” time of 90 minutes, “but we just haven’t engineered our emergency rooms to cut out some of these steps that aren’t needed” and cause delays, Nabel said.