The Authors intended to verify if in a CCU in a Hospital in a country town, the precoronary times were different from those pointed out in the series of cases relatives to the Hospitals of a big town and if the possible remark of different times is liable to be translated into different epidemiologic results. The remarks have been effected on 80 patients affected by acute myocardial infarction; the average of the precoronary time resulted into 13h,43', slightly lower than that observed in the other Hospitals in Lazio. Particularly the 27,5% of the patients was admitted into the Hospital within one hour from the onset of their symptoms and the 65% within six hours, which shows an hospitalization in the very early period. Though in this group dangerous arrhythmias (ventricular fibrillation included) have been observed frequently, it has not been remarked a mortality greater than in other series of cases, and explains the high mortality for arrhythmia observed in our series of cases (21,4% of all deaths), considering the high frequency of dangerous arrhythmias (V.F. included) noticed in the first hours of myocardial infarction.