Changes in pulse rate among the civilian population during air-raid alerts in the city of Zagreb.

This investigation was performed in Zagreb and its surroundings in 1991 and 1992 during the war against Croatia. The study included 50 civilians who, at the moment of the sounding of the air-raid siren, had a continuous electrocardiogram recorded as part of the routine cardiologic examination. The frequency of the pulse was read out from the electrocardiogram at four different times: before the sounding of the siren, the moment of the sounding of the siren, the moment of cessation of the alert, and 1 hour afterward. The mean values of the pulse were calculated for each time point. The subjects were divided into four groups according to the length of exposure to the air-raid alerts (September 15, 1991 to January 3, 1992). The results show a significant increase in pulse frequency at the moment of the sounding of the air-raid siren compared with before the air-raid siren (p < 0.001). However, no significant difference was found between the beginning and the end of air-raid alert campaign (p > 0.05). We conclude that within the civilian population of the city of Zagreb there was no adaptation to traumatic war situations as indicated by a lack of pulse reaction after a period of time under air-raid alerts. In other words, civilians always reacted with increased pulse frequency at the moment of the sounding of the air-raid siren.