SummaryAims: The goal of the study was a preliminary assessment of the occurrence of post-traumatic stress disorder (PTSD) among patients awaiting major heart surgery and the assessment of the reliability of the Impact of Event Scale -Revised (IES-R). The study was inspired by publications indicating a high rate of PTSD among cardiac patients. Methods:In total, 100 consecutive patients scheduled for non-emergency cardiac surgery were screened using a brief list of PTSD symptoms. Those who responded affirmatively were further assessed with the IES-R, the structured Mini-International Neuropsychiatric Interview (M.I.N.I.) and a clinical assessment according to the DSM-5 criteria.Results: Out of the 15 patients who completed the IES-R, in 14 a possibility of PTSD was noted. Five refused to undergo a psychiatric examination, and of the remaining 9 patients, 4 met PTSD criteria according to M.I.N.I. and DSM-5. One case of PTSD was related to cardiac problems. Discussion:The results of the present study do not support the hypothesis that heart disease is a stressor causing PTSD in patients awaiting cardiac surgery. Moreover, the study calls into question conclusions suggesting high rates of PTSD among some populations of cardiac patients in research conducted with self-rating scales. It demonstrates that clinical psychiatric examination is necessary to properly confirm a PTSD diagnosis. Conclusions:The prevalence of PTSD in the study group (4%) was higher than in the general population in Poland, but the heart disease-related stressor was found only in one case (1%), a rate equal to the rate of PTSD. The reliability of IES-R is low due to a large number of false positives.anxiety, cardiac patients, depression, Impact of Event Scale-Revised, post-traumatic stress disorder