Schull MJ, Vermeulen M, Slaughter G, et al. Emergency department crowding and thrombolysis delays in acute myocardial infarction. Ann Emerg Med; in press.

Heart attack patients treated in EDs experiencing a great deal of crowding were 40% more likely to experience a major delay, defined as a door-to-needle time of 60 minutes or more, before receiving a clot-busting drug.

The median door-to-needle time was 5.8 minutes longer for these patients than for those treated in EDs experiencing no crowding.

The study included 3,452 suspected heart attack patients cared for at 25 hospital EDs over three years in Ontario, Canada.

Median door-to-needle time in the study was 43 minutes, and 40, 45, and 47 minutes in conditions of none, moderate, and high ED crowding, respectively.

"ED crowding . . . may represent a barrier to improving cardiac care in EDs," the authors concluded.