Need an ambulance? Why you may not want the more sophisticated version.

Patients who are having a heart attack, stroke or other serious health emergency have a greater chance of surviving if they're taken to the hospital in a basic life-support ambulance rather than one loaded with sophisticated equipment, according to a study released Monday.

Contrary to what most people might think, critically ill patients actually do better when transported in the more basic ambulances staffed by emergency medical technicians, instead of advanced life-support vehicles that have paramedics equipped to perform more invasive procedures.