Objectives: To provide a contemporary account of the treatment and outcomes of acute coronary attacks in England and Wales and to identify strategies that might improve the outcome. Design: Two year community and hospital based study in three British health districts. Setting: Health districts of Brighton (population 282 000), South Glamorgan (408 000), and York (264 000). Subjects: 3523 men and women under 75 years of age who died outside hospital from acute coronary causes, who were admitted to hospital with acute myocardial infarction, or who developed acute infarction or died unexpectedly from acute coronary causes while they were already in hospital. Interventions: Attempted resuscitation in people having a cardiac arrest outside hospital. Main outcome measures: Total case fatality, case fatality outside and inside hospital, and the effect of resuscitation on case fatality outside hospital. Results: 1589 patients died within 30 days of the acute event. Case fatality was 45% (95% confidence interval 43% to 47%), rising from 27% (160/595) (23% to 31%) at age Conclusion: Opportunities for reducing fatality from acute coronary attacks lie mainly outside hospital. These results and others imply that survival from cardiac arrest outside hospital might be trebled by improved ambulance and patient response. Proper application of secondary preventive measures for patients with coronary disease could have an even larger impact. In three health districts during 1994-5 total case fatality for people under 75 years of age was 45% and 74% of fatal events happened outside hospital The likelihood of a fatal event occurring outside hospital was greater for people under 55 years of age (91%) than for those aged 65-74 years (70%) Total fatality was reduced appreciably (by 1.7%) by resuscitation outside hospital, but this proportion might possibly be trebled by further upgrading of ambulance services Because 46% of people who died were already known to have coronary heart disease, improved secondary prevention may have a major part in further reducing mortality