A Multicenter Study on the Normal Reference Range and Clinical Significance of the Right Atrioventricular Coupling Index Assessed by Artificial Intelligence-Based Three-Dimensional Echocardiography

Healthy Adults Group

Inclusion criteria

• Participants must meet all of the following criteria to be enrolled:

• Of Han Chinese ethnicity
• Aged 18-79 years
• Normal blood pressure (< 140/90 mmHg)
• Normal fasting blood glucose
• Normal blood lipid levels (triglycerides, total cholesterol, low-density lipoprotein, high-density lipoprotein)
• Normal complete blood count results (hemoglobin concentration, white blood cell count, red blood cell count, platelet count)
• Normal liver and renal function (alanine transaminase < 2× upper limit of normal; normal creatinine and blood urea nitrogen)
• Normal electrocardiogram results (occasional atrial premature beats may be enrolled at the investigator's discretion)
• No structural heart disease and normal cardiac function confirmed by echocardiography

Exclusion criteria

Participants will be excluded if they meet any of the following criteria:

• Clinically significant cardiac valve regurgitation (≥ mild severity)
• Respiratory diseases: acute or chronic respiratory disorders
• Endocrine diseases: thyroid disease, diabetes mellitus, hyperaldosteronism, pheochromocytoma, etc.
• Abnormal liver function (alanine transaminase > 2× upper limit of normal), abnormal renal function (elevated creatinine beyond normal range), or dyslipidemia (elevated triglycerides, total cholesterol, low-density lipoprotein, or high-density lipoprotein)
• Other systemic diseases: anemia, malignancy, connective tissue disease, large artery/peripheral vascular diseases (aortic dilation, aortic dissection, coarctation of the aorta, Takayasu arteritis, atherosclerosis), etc.
• Pregnant or lactating women
• Professional athletes
• Poor-quality ultrasound images that cannot support parameter measurement and analysis

Pulmonary Hypertension Group

Inclusion criteria

Patients must meet all of the following criteria to be enrolled:

• Aged 18-79 years
• Confirmed diagnosis via right heart catheterization: mean pulmonary arterial pressure (mPAP) ≥ 20 mmHg, in accordance with the 2022 ESC/ERS guidelines

Exclusion criteria

Patients will be excluded if they meet any of the following criteria:

• Unable to complete right heart catheterization or pressure-volume loop assessment
• Complicated with significant left heart disease (left ventricular ejection fraction [LVEF] < 50%, significant mitral valve disease)
• Pericardial disease or arrhythmias (e.g., atrial fibrillation) that severely impair right heart function evaluation
• Poor-quality images that prevent accurate measurement of right atrial or right ventricular parameters
• Concurrent liver or renal disease
• Concurrent malignancy
• History of surgical procedures such as pulmonary endarterectomy or balloon pulmonary angioplasty

Heart Failure Group

Inclusion criteria

Patients must meet all of the following criteria to be enrolled:

• Aged 18-79 years
• Meets the 2022 AHA/ACC/HFSA diagnostic criteria for heart failure

Exclusion criteria

Patients will be excluded if they meet any of the following criteria:

1.Complicated with significant valvular heart disease (e.g., severe mitral regurgitation, severe tricuspid regurgitation, etc.)

Tricuspid Regurgitation Group

Inclusion criteria

Patients must meet all of the following criteria to be enrolled:

• Moderate or severe primary or secondary tricuspid regurgitation confirmed by echocardiography
• Aged 18-79 years

Exclusion criteria

Patients will be excluded if they meet any of the following criteria:

• Pericardial disease or arrhythmias (persistent atrial fibrillation) that interfere with measurements
• Congenital heart disease or residual lesions after surgical correction

Atrial Septal Defect Group

Inclusion criteria

Patients must meet all of the following criteria to be enrolled:

• Secundum atrial septal defect confirmed by echocardiography or transesophageal echocardiography
• Patients who have not undergone closure or surgical correction, or stable patients with > 3 months postoperatively
• Aged 18-79 years

Exclusion criteria

1.Complicated with other complex congenital heart diseases.