Ambulance utilization by patients with acute myocardial infarction.

Fifty-five per cent (73/133) of myocardial infarction (MI) patients on Cape Cod during a three-month period reached the hospital by ambulance. the 45 per cent (60/133) not using ambulances were compared to users to identify a subpopulation to which public health programs might be directed to increase appropriate use of cardiac ambulances. Univariate analyses showed a distnce of more than ten miles from the hospital, and a prior history of MI distinguished ambulance users from non-users. Demographic/economic status, delay in seeking care, presenting symptoms, Killip class, and in-hospital mortality rates were not signigicantly different. Step-wise discriminant analysis identified four predictive variables in rank order: distance from the hospital, past history of MI, symptoms of fainting, and negative history for hypertension which correctly classified 72 per cent of our population with respect to ambulance utilization.