Emergency departments in the United States are busier than ever before. Americans now make around 15 million more emergency room visits each year than they did a decade ago. At the same time, the number of emergency departments has decreased.

The result is overcrowding and longer waiting times before seeing a doctor. A new national study by researchers at Harvard Medical School has found that Americans waited 36% longer for emergency care in 2004 than they did in 1997 - an average increase of 8 minutes per visit.

But patients who had suffered a heart attack had the largest increase, from just 8 minutes in 1997 to an average of 22 minutes in 2004. One in four heart attack patients had to wait 50 minutes or more, but men were slightly quicker to get a doctor's attention than women. They were seen by a doctor around 4 minutes sooner.

Researchers say that without added funding for more beds, rooms, and staff, emergency department waits are just going to keep on increasing.