This observational multicentric national study aims to understand better acute myocardial infarction (heart attack) in young adults aged 45 years or younger in Serbia. By analyzing patient characteristics, medical history, test results, and treatment outcomes, the research seeks to identify factors contributing to heart attacks in this population and improve prevention and treatment strategies. Participants will undergo routine tests during hospitalization, and specific blood samples will be collected for advanced analyses, including genetic testing. Follow-up will include periodic check-ins to monitor health outcomes. The study will also explore differences in heart attack causes and outcomes in younger individuals compared to older populations, focusing on risk factors like smoking, cholesterol levels, and genetic predisposition. Participation is voluntary, and all collected data will remain confidential.