The aim of this study was to assess the impact of a mobile emergency care unit (MECU) staffed with an anaesthetist, in terms of increased survival among patients with acute myocardial infarction (MI). The setting was an urban area with 330 000 inhabitants. This was a quasi-experimental before-and-after-study including consecutive emergency calls during September to November 1996 (Period 1, without the MECU) and September to November 1997 (Period 2, including the MECU). Fifty-four ambulance patients had their MI diagnosis confirmed at hospital during Period 1, and another 54 in Period 2. The 28-day mortality was collected from relevant registers. Twenty-four (44%) of Period 2 patients were transported by the MECU. MECU patients had lower systolic blood pressure (SBP) than other patients, both before and after hospital admission. Nitroglycerine treatment was relatively frequent in MECU patients, and cardioversion, anaesthesia and intubation was applied exclusively in these patients. After arrival at hospital, MECU patients had thrombolysis relatively often (46% versus 23% in other Period 2 patients) but percutaneous transluminal coronary angioplasty (PTCA) relatively infrequently (21% vs 30%). The total mortality was significantly lower in Period 2 than in Period 1 patients (11% vs 21%,