Effectiveness of the call-out system for a London Coronary Ambulance service.

St Bartholomew's Hospital, in the City of London, has for many years run a Coronary Ambulance service, called by the public via the 999 system. During a 9-month period only 55% of 214 cardiac emergencies arriving at St Bartholomew's Hospital came with Coronary Ambulance support, although the service was available if called. In cases where the Coronary Ambulance was summoned, the call-out was inappropriate in 57% of cases. In addition, 153 cardiac emergencies arrived at the Accident and Emergency Department during hours when the Coronary Ambulance was not available. Reasons for breakdowns in the call-out system are discussed and remedies involving the public and London Ambulance Control are suggested.