This multicenter study aims to establish the normal reference range of the Right Atrioventricular Coupling Index (RACI) in healthy Chinese adults using AI-based 3DE technology. It will also analyze the correlation between RACI and physiological parameters such as age, gender, and body surface area. Additionally, the study will explore the variation characteristics of RACI in patients with pulmonary hypertension, heart failure, tricuspid regurgitation, and atrial septal defect, and evaluate the clinical value of RACI in disease diagnosis, differential diagnosis, and risk stratification.