Here is the design of a clinical trial:

Official Title: Shunt Quantification in Atrial Septal Defect Using Inert Gas Rebreathing and Thoracic Bioimpedance: Comparison With the Gold Standard Method

Included conditions:
- Congenital Heart Diseases
- Hemodynamic
- Cardiac Output

Study Armgroups:
- {'label': 'patients with Atrial septal defect type Ostium Secundum', 'type': 'EXPERIMENTAL', 'description': 'patients with Atrial septal defect type Ostium Secundum, eligible for an interventional closure', 'interventionNames': ['Device: Innocor®', 'Device: Physioflow®']}

Interventions:
- {'type': 'DEVICE', 'name': 'Innocor®', 'description': 'Inert gas rebreathing device: Innocor® (Innovision, Odense, Denmark)', 'armGroupLabels': ['patients with Atrial septal defect type Ostium Secundum']}
- {'type': 'DEVICE', 'name': 'Physioflow®', 'description': 'Bioimpedance cardiograph: Physioflow® (Manatec, France)', 'armGroupLabels': ['patients with Atrial septal defect type Ostium Secundum']}

Primary Outcomes:
- {'measure': 'shunt fraction', 'description': 'Accuracy of Qp/Qs ratio measurements by the double non-invasive technique and the gold standard method (non-invasive: Echocardiography Doppler; invasive: direct Fick method) before interventional closure of ASD', 'timeFrame': 'at 1 hour'}

Please estimate the sample size based on the assumption: 
power of 90%, two-sided type I error at 5%, sequential exploratory analysis every 10 patients without correction of type I error
Estimation of sample size
          To evaluate the agreement between the double non-invasive approach and the gold standard technique, a sample size of 30 subjects would provide a power of 90% to highlight an agreement of 0.8 (Linâs concordance coefficient) for a two-sided type I error at 5%. A sequential exploratory analysis will be proposed each 10 patients without correction of type I error.