Abstract Funding Acknowledgements Type of funding sources: None. Background Each year cardiovascular disease (CVD) causes 3.9 million deaths in Europe, accounting for 45% of all deaths. CVD are especially relevant not only due to the high mortality rate related to them, but also due to the disability associated with them. In Portugal, one of the specific skills of the medical-surgical nurse is to take care of the person and family / caregivers experiencing complex medical processes (such as acute coronary syndrome - ACS), resulting from chronic disease (such as coronary heart disease - CHD). The medium-range theory of transitions, by Meleis and collaborators, helps to frame the theoretical aspects in nursing practice. Nursing approaches to the person with CHD, are often focused on transmitting knowledge and teaching abilities, regardless of the perception the person may have of the need to pursue changes in his/her life. Purpose This study aimed at gathering information on how a person perceives, has knowledge, and recognises an acute coronary event as a moment of transition. It is intended to evaluate the level of awareness the person has of his/her situation in this health-illness transition, as to incorporate an approach based upon the transition’s theory. Methods The study was conducted on a Cardiology ward and Intensive Care Unit of a tertiary hospital in Northern Portugal, on the second half of September 2020. All patients admitted with an ACS were eligible. A qualitative research framework was adopted, using the semi-structured interview. When phrasing some questions, the phenomenological approach was adopted. Results Four patients were included. Their interviews showed a wide variability of knowledge about the motive for admission or what caused it; there was an uneven perception of the severity of the event; in general, they did not recognize the need to make changes in their lives or externalized the responsibilities for it. This study was limited by a reduced number of interviews conducted, limiting the generalization of the findings and conclusions, though it was not the purpose of this exercise. Also, the interviews were performed in different moments after admission, so some of the patients had already been approached by the nursing staff in moments of health education, which may lead to information bias. Conclusions The traditional health education approach based on teaching the patients a set number of items needed to achieve a healthier lifestyle after an ACS, seem to produce very variable effects on how the person recognizes, perceives, and knows about his/her condition. The transition theory framework may be useful to engage patients in the process and, considering the reduced length of stay in the hospital, it is necessary the transition of care to the community. Awareness is a central concept in the patient"s adaptive process and, therefore, a major theme for nursing practice. Considering the apparent scarcity of evidence about it, it reveals to be an area of future investment.