Atrial secondary tricuspid regurgitation (A-STR) is a distinct phenotype of secondary tricuspid regurgitation characterized by right atrial (RA) dilation and normal right and left ventricular function. It is most common in elderly women with atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF). A-STR occurs due to significant tricuspid annulus (TA) dilation from RA enlargement, leading to insufficient leaflet coverage. Unlike ventricular STR (V-STR), A-STR typically lacks leaflet tethering. A-STR accounts for 10–15% of clinically relevant tricuspid regurgitation and has better outcomes than V-STR. Recent data suggest that A-STR patients may benefit from aggressive rhythm control and timely valve interventions. However, current guidelines lack consistent definitions and management strategies for A-STR. This document aims to define A-STR, review its pathophysiology, diagnosis, and management, and provide a standardized nomenclature. A-STR is defined by specific quantitative criteria to distinguish it from V-STR. It is a diagnosis of exclusion, requiring ruling out alternative causes of primary TR. A-STR is associated with better survival and outcomes compared to V-STR, and early rhythm control and valve interventions are recommended. Imaging challenges include accurate assessment of RA and TA dimensions, with 3D echocardiography and cardiac MRI providing better accuracy. Treatment options include medical therapy, rhythm control, and surgical or transcatheter interventions. A-STR patients may benefit from transcatheter tricuspid valve interventions (TTVIs) due to preserved bi-ventricular function and efficient RV-PA coupling. However, the role of surgery and TTVIs in A-STR remains under investigation. Overall, A-STR requires a multidisciplinary approach for optimal management.Atrial secondary tricuspid regurgitation (A-STR) is a distinct phenotype of secondary tricuspid regurgitation characterized by right atrial (RA) dilation and normal right and left ventricular function. It is most common in elderly women with atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF). A-STR occurs due to significant tricuspid annulus (TA) dilation from RA enlargement, leading to insufficient leaflet coverage. Unlike ventricular STR (V-STR), A-STR typically lacks leaflet tethering. A-STR accounts for 10–15% of clinically relevant tricuspid regurgitation and has better outcomes than V-STR. Recent data suggest that A-STR patients may benefit from aggressive rhythm control and timely valve interventions. However, current guidelines lack consistent definitions and management strategies for A-STR. This document aims to define A-STR, review its pathophysiology, diagnosis, and management, and provide a standardized nomenclature. A-STR is defined by specific quantitative criteria to distinguish it from V-STR. It is a diagnosis of exclusion, requiring ruling out alternative causes of primary TR. A-STR is associated with better survival and outcomes compared to V-STR, and early rhythm control and valve interventions are recommended. Imaging challenges include accurate assessment of RA and TA dimensions, with 3D echocardiography and cardiac MRI providing better accuracy. Treatment options include medical therapy, rhythm control, and surgical or transcatheter interventions. A-STR patients may benefit from transcatheter tricuspid valve interventions (TTVIs) due to preserved bi-ventricular function and efficient RV-PA coupling. However, the role of surgery and TTVIs in A-STR remains under investigation. Overall, A-STR requires a multidisciplinary approach for optimal management.