Background: ASD associated with significant right ventricular (RV) volume overload causes left ventricular (LV) dysfunction, manifested by decreased peak LV systolic pressure, peak dp/dt, prolonged Tau and decreased filling rate. Marked LV deformity in ASD patients causes heterogeneous wall stress, which may lead to heterogenecity of wall strain and dyssynchronicity. Furthermore, heterogenecity of LV wall stress may impair LV torsion. Objectives of this study are: 1) to evaluate the wall strain of all LV-segments before and after trans-catheter ASD closure (ASDCL), 2) to evaluate synchronicity of LV wall, 3) to evaluate the change of LV torsion.
Methods: Twenty ASD patients (Age 17.2 years (6.9-57.2) (median (range)) were included. All patients had successful ASDCL. Echo data were obtained before, 48 Hr after and 3 months after ASDCL. Radial and circumferential strains of 18 segments of LV were measured in short-axis at base, mid and apex. Peak strain and torsion were measured. Synchronicity was assessed as a standard deviation of time from QRS to peak strain of all segments.
Results: 1) Apical circumferential strains were significantly improved (P<0.05). However, ejection fraction did not change. 2) Synchronicity was significantly improved after ASDCL: pre: 51.4 ms (34.2-78.5); 48Hr 39.9 ms (30.9-60.3) (P<0.05); 3M 40.4 ms (22.3-57.8) (P<0.01). 3) Torsion did not change: pre 11.0 degree (2.3-15.6); 48Hr 12.0 (5.3-16.9); 10.9 (2.2-17.6).
Conclusion: Although the ejection fraction did not change, apical circumferential strains and synchronicity of LV were improved, suggesting improved efficiency of LV contraction by removal of RV volume overload.