WASHINGTON (Reuters) - Patients seeking urgent care in U.S. emergency rooms are waiting longer than in the 1990s, especially people with heart attacks, U.S. researchers reported on Tuesday.

A women looks back at the emergency room entrance of the Biloxi regional Medical Center in Biloxi, Mississippi August 30, 2005. REUTERS/Mark Wallheiser

They found a quarter of heart attack victims waited 50 minutes or more before seeing a doctor in 2004. Waits for all types of emergency department visits became 36 percent longer between 1997 and 2004, the team at Harvard Medical School reported.

Especially unsettling, people who had seen a triage nurse and been designated as needing immediate attention waited 40 percent longer -- from an average of 10 minutes in 1997 to an average 14 minutes in 2004, the researchers report in the journal Health Affairs.

Heart attack patients waited eight minutes in 1997 but 20 minutes in 2004, Dr. Andrew Wilper and colleagues found.

“If a loved one has a heart attack, it doesn’t matter whether he is well insured. He still has a one-in-four chance of waiting over 50 minutes, because of ED (emergency department) overcrowding, and this wait will only increase,” Dr. Robert Lowe, an emergency medicine expert at Oregon Health and Science University who did not work on the study, said in a statement.

Wilper’s team used U.S. Census survey and National Center for Health Statistics data for their study, which covered more than 92,000 emergency department visits.

They used other surveys to calculate that the number of emergency room visits rose from 93.4 million in 1994 to 110.2 million in 2004.

During the same time, 12 percent fewer hospitals operated emergency rooms, according to the American Hospital Association.

“EDs close because, in our current payment system, emergency patients are money-losers for hospitals,” Wilper said in a statement.

Harvard’s Dr. David Himmelstein, who worked on the study, also lobbies for some kind of national health care system. “One contributor to ED crowding is Americans’ poor access to primary and preventive care, which could address medical issues before they become emergencies,” Himmelstein said in a statement.

The American College of Emergency Physicians said the findings were not surprising.

“Emergency physicians have said for years that crowding and long wait times are hurting our patients -- insured and uninsured equally,” ACEP president Dr. Linda Lawrence said in a statement.

“Ever-lengthening waits are a frightening trend because any delays in care can make the difference between life and death for some patients. The number of emergency patients is increasing while the number of hospital beds continues to drop. It is a recipe for disaster.”

The study is available onlinehere