Abstract
<jats:p>Introduction. Common atrium is a rare and severe congenital heart defect combined with the absence of atrial septum and impaired atrioventricular valve formation. Without surgical intervention, this anomaly is associated with high morbidity and mortality. The aim of our study was to demonstrate modern approaches to diagnosis and surgical treatment of common atrium using a clinical case example with parallel analysis of literature data. Materials and Methods. We present a clinical case of a 17-year-old patient with the diagnosis of common atrium confirmed by echocardiography and other instrumental methods. Definitive repair of the defect was performed with Boyd tricuspid valve annuloplasty. A scientific literature search was conducted in the leading scientific databases, such as PubMed, Scopus, Web of Science, Google Scholar, and eLIBRARY (RINC), covering publications in English and Russian for the period of 2010-2025. The following keywords were used: common atrium, single atrium, atrioventricular septal defect, congenital heart defects, surgical correction, radical repair, tricuspid valve annuloplasty, Boyd technique, long-term outcomes, echocardiographic diagnosis, clinical case, using AND/OR logical operators. Sources were selected with the priority given to systematic reviews, clinical cases, and studies with data on surgical treatment and long-term outcomes. Results and Discussion. Surgical intervention achieved sustained clinical stabilization and restored hemodynamics. The long-term results are favorable. Literature data confirm the effectiveness of radical repair in adolescence. Conclusion. Advanced diagnostic methods and timely surgical treatment of common atrium provide a significant improvement in prognosis. The case presented illustrates the clinical implementation of the recommendations available in the current literature.</jats:p>