Objective:

To evaluate the impact of atrialised right ventricle (aRV) volume on cardiac output during exercise in un-operated patients with Ebstein anomaly (EA).

Approach:

• Patient Selection: Thirteen un-operated EA patients aged 12–50 years were selected from cardiology databases, excluding those with MRI incompatibility or significant left ventricular dysfunction.
• Cardio-Pulmonary Exercise Testing: CPET was performed to measure maximum oxygen consumption (VO2 max) using a ramp protocol on a cycle ergometer.
• Echocardiography: Transthoracic echocardiography assessed tricuspid regurgitation (TR) severity and morphology.
• Cardiac Magnetic Resonance Imaging: CMRI was conducted at rest and during exercise to measure flow in the aorta and pulmonary artery, and to analyze volumetric data.
• Data Analysis: Cardiac index (CI) was calculated from flow data, and volumetric analysis was performed to derive EA disease severity indices.

Key Findings:

• The volume of the aRV significantly impacts cardiac output during exercise.
• Echocardiographic and CMRI parameters correlate with exercise capacity in EA patients.
• TR severity assessed by echocardiography was strongly correlated with TR fraction derived from CMRI.

Interpretation:

Limitations:

• Small sample size of 13 patients limits generalizability.
• Exclusion of patients with significant left ventricular dysfunction may affect results.

Conclusion: