The authors have attempted to design and verify by means of mathematical modelling methods a model of comprehensive (medical, social and psychological) prognosis in cardiovascular disease, which would cover different aspects of patients’ disease, treatment and life functioning and would be relevant to the objectives of the treatment and rehabilitation process. A multidisciplinary set of methods was used to accomplish the aim: clinical and psychological. The study included 437 patients with coronary heart disease and/or chronic heart failure undergoing surgical treatment.Part I of the article presents the results of the first 4 stages of the study.1) A theoretical prediction model based on existing data was developed and empirically tested on different patient populations at various stages of surgical treatment. 2) An overall information database was compiled on the basis of our own research. A total of 245 indicators were taken into account; they were expertly divided into five groups: clinical, socio-behavioural, personality characteristics, emotional state indicators, and cognitive functioning indicators.3) The missing cells in the sampling matrix were filled in by means of mathematical modelling and neural networks. 4) An exploratory factor analysis of all characteristics in the allocated groups was performed, resulting in 24 factors: 3 in the group of clinical characteristics (“Coronary heart disease”, “Transplantation”, “Patient’s age and duration of heart failure”), 6 in the group of socio-behavioural (“Social and occupational orientation”, “Keeping a habitual lifestyle in spite of illness”, “Occupational strain”, “Lifestyle”, “Non-adherent behaviour”, “Occupational stress”), 5 in the group of personality characteristics (“Attitude towards illness”, “Motivational orientation”, “Decreased resilience”, “Irrational beliefs”, “Coping strategies and coping resources”), 4 in the group of emotional state characteristics (“Dominant emotional state and feelings”, “Quality of life and mood”, “Absence of anxiety at the moment of the study”, “Functioning in conditions of illness”), 6 in the group of characteristics of cognitive functioning (“Neuropsychological characteristics”, “Spatial–constructive thinking and pace of mental activity”, “Visual memory”, “Attention and verbal–logical thinking”, “Verbal memory”, “No significant decrease in IQ”).