Analysis of time intervals involved in admission to a coronary care unit.

Time intervals between the onset of the presenting symptom (chest pain) and arrival in a coronary care unit were studied for 221 admissions arranged by conventional means. The median figure for "patient delay" was 60 minutes, for "general-practitioner delay" 20 minutes, for "ambulance delay" 30 minutes, and for "transit delay" 30 minutes. The median "total delay" was three hours 30 minutes.Only 4.5 per cent of the patients were under intensive coronary care within one hour, the time of the highest mortality risk. A mobile coronary service should be capable of increasing the proportion of patients brought under special care within the first hour, but the time taken by the patient to realise the nature of the emergency and summon aid is likely to remain the most critical factor.