A two-year population study in the district of Prague 4 (population 190 000) showed that patients with acute myocardial infarction [AMI] came to the hospital with a considerable delay (median 10.25 hours), whose substantial part was caused by the patient's lingering in calling for medical aid (a half of them called as late as within 3 hours since the appearance of symptoms). On the other hand, out of 226 cases of sudden death caused by ischaemic heart disease (IHD), 92% of the victims died as early as within the first hour. Within the first hour, 27% of all patients with coronary attacks in the community died, and as a few as 2% only were hospitalized within this period. No prevention of sudden coronary death is possible for the time being. Nevertheless, an attempt can be made at least to reduce the risk of early death in the following two ways. The public shoudl be avised of the gravity of characteristic symptoms of AMI, danger in the case of delay, and necessity of prompt medical aid. Because a majority of victims of sudden death have positive histories of IHD, and most deaths occur in the patients' homes in the presence of their family members, these next relatives of patients with manifest IHD should be trained in the performance of cardiopulmonary resuscitation.