The effect of Atrial Septal Defect (ASD) closure by using larger devices on the improvement in biventricular function remains an area of active research. Therefore, the aim of the current study is to assess the degree of improvement in biventricular dimensions and function by using 2-Dimensional echocardiography derived Strain and Strain Rate and Tissue Doppler. Moreover, to identify the relationship between the left and right ventricular systolic and diastolic function and device size.

In most echocardiographic studies, left ventricle (LV) systolic function was normal in the patients with ASD and only a few cases had a reduced LV ejection fraction with severe right ventricle (RV) volume overload. The device closure of ASD increases immediately the blood flow to the left ventricle and may unmask subtle abnormalities in systolic and diastolic function. Currently, clinical research in cardiac mechanics is moving from short- and long-axis LV and RV function and ejection fraction to two and three- dimensional (2D, 3D) ventricular deformation studies (Strain and Strain Rate quantification). These methods are independent of ventricular geometry and allow quantification of myocardial motion and deformation in different directions (longitudinal, radial, and circumferential), while conventional methods mainly rely on the assessment of radial function. Strain imaging has also been used to demonstrate that patients who underwent device closure of an ASD had better LV and RV longitudinal deformation than patients who underwent surgical closure of an ASD. However, the effect of device size on the LV systolic and diastolic function is still under investigations. For all these reasons the researchers intend to measure RV and LV haemodynamic changes by 2-D Transthoracic Echocardiography (TTE) derived Tissue Doppler and Strain quantification in ASD before and after transcatheter closure with special emphasis on the assessment of the relationship between device size and biventricular systolic and LV diastolic function.

Inclusion Criteria:

• All ASD patients who have been already selected and suitable for intervention before the starting time of the study. The criteria for ASD intervention are either haemodynamically significant shunt fraction (Qp/Qs > 1.5) or echocardiographic signs of right heart dilation or RV volume overload and pulmonary hypertension related symptoms.

Exclusion Criteria:

• Patients with a large stretched Secundum ASD ≥ 36 mm, those with insufficient ASD rims (except the aortic rim), sinus venosus or primum type ASD, irreversible pulmonary hypertension, other associated structural heart diseases, coronary artery disease, LV systolic dysfunction, atrial fibrillation, or hypertension.

The study includes two groups: 1. Patients with isolated Secundum ASDs who are referred for possible elective transcatheter closure of the defects. Comparison between the results of the haemodynamic 2D echocardiography derived Strain and Strain Rate imaging procedure will be done as follow:

a. Echo 1 - performed just before the procedure b. Echo 2 - performed the day after the procedure c. Echo 3 - performed 1-3 months following the procedure

2. Control group: age and gender-matched healthy subjects are being examined to assess their LV and RV haemodynamic parameters and strain results and compare these data with the study group.