Objective: The aim of this thesis is to determine the frequency of diseases of the circulatory (blood vessel) system treated at ZHM SDŽ, viewed through the time before the onset of the COVID-19 pandemic, the year of the COVID-19 pandemic, and the time after the end of the COVID-19 pandemic. Materials and methods: This retrospective study includes all patients who received medical care in the period from March 2019 to March 2022 in the Department of Emergency Medicine. Information about their age, gender and diagnosis according to the ICD-10 classification was collected at the Department of Emergency Medicine of the Split-Dalmatia County. The analyzes were carried out through the medical program „e-Hitna“. Results: The largest number of patients was present in the year before the COVID-19 pandemic. In relation to age and gender, the incidence is higher in the female population between the ages of 65 and 100. A greater number of patients who sought help in outpatient clinics during the three observed years was recorded, despite the greater number of requests for intervention by the emergency medicine team between the ages of 65 and 100. The incidence seen in relation to the months throughout the year shows an increase in diseases in the summer months, where we have the highest number of patients in August, and a slight increase is also recorded in the winter months (December, January), which is also a consequence of the influence of tourism. Conclusions: During the COVID-19 pandemic, there is a sharp drop in the number of patients. Along with the progress of the pandemic, the female population and the older age group continue to have prestige in the incidence of the disease. In contrast to the first observed year, which preceded the COVID-19 pandemic, in the second and third observed years, a higher percentage was spent on the interventions of the ZHM SDŽ team, compared to the number of patients in outpatient clinics. A comparison of the total number of patients with the number of M and H category patients in individual months indicates the influence of tourism on the very distribution of the incidence of diseases.