The highest incidence of out-of-hospital cardiac arrest during a circadian period in survivors.

Unlabelled: Health care associated with cardiac arrest exhibits a significant economic burden, rather than effectiveness.

Hypothesis: The time of the out-of-hospital cardiac arrest (OHCA) onset during a diurnal period alters the survival chance. Professionally resuscitated patients for witnessed OHCA (n = 495) from the study were prospectively followed for 12 months. The distribution of the onset of cardiac arrest during the 24-hour period was tested in the survivors (the total group, the other groups). In the ultrashort-term survivors (n = 136, follow-up = admission to hospital) the highest incidence was seen between 18:01-22:00 h. The same trend was seen in both the short-term (n = 48, follow-up = discharge from hospital) and the long-term survivors (n = 39, follow-up = 1 year). Furthermore, when the ultrashort-, short-, and long-term survivors were analysed according to indicators of prehospital care (early electrical defibrillation < or =5 min, bystander cardiopulmonary resuscitation, ambulance response time < or =10 min; locations of arrest; initial cardiac rhythms) an OHCA peak was observed for early defibrillation and ambulance response time (ultrashort-term survivors, 18:01-22:00 h) and/or in the case of OHCA that occurred in a public place (short-term survivors, 18:01-22:00 h). The lowest incidence of cardiac arrest was between 22:01-06:00 h in all groups. The evening incidence of OHCA reflects a higher chance of survival in our study area (East Bohemian region).