Abstract 3034: Atrial Septal Defect leads to increased and reversible torsion of both ventricles - a MR-Tagging study
Introduction: Tagging in Cardiac magnetic resonance imaging (MR) is a validated method for point to point contraction analysis of the heart. We assessed the hypothesis that right and left ventricular torsion in patients with atrial septal defect (ASD) is different from normal. Right ventricular torsion was thought to be more affected due to RV volume load.
Methods: MR-Tagging (CSPAMM acquisition, data evaluation based on HARP) was performed for both the right an left ventricle. Short axis cuts at three different levels of the ventricle were evaluated. Clockwise and anticlockwise torsion of both ventricles was measured during systole and diastole. Systolic and diastolic torsion were summed up and given in total ventricular torsion. In addition, enddiastolic volume of RV and LV were measured by conventional steady state free precession scans. Left-to-right shunt over the ASD was measured by MR flow measurements in the main pulmonary artery and ascending aorta (Qp/Qs). Patients: Eight healthy subjects (age (years) 24.6±15.6, range 7– 48); nine patients (28.0±24.8, range 6 – 68) before and after interventional ASD closure by Amplatzer ASD-Occluder (16–25mm).
Results: After ASD occlusion Qp/Qs declined from 1.96±0.45 to 1.01±0.34 (p=0,03). The right ventricular enddiastolic volume decreased (101,0±27,7 ml/m2 vs. 82.8±20.1 ml/m2) while the left ventricular enddiastolic volume (58.3±16.4 ml/m2 vs. 64.18±19.58 ml/m2) increased. Compared to healthy subjects (RV at base: 4.3±1,4°; LV at base: 5.8 ±1.3°) patients with ASD showed increased total ventricular torsion in both ventricles (RV at base: 6.9±2.5°; LV at base: 9.5 ± 4.0°) and at all levels of the ventricles (Base, mid portion, apex). A negative linear correlation between torsion and shunt volume (r2=0.86; p=0.002) could be demonstrated. After ASD closure ventricular torsion was reduced and values converged to normal.
Conclusion: In the presence of RV volume load due to ASD total ventricular torsion is increased in both ventricles. After ASD closure torsion of both ventricles decreases although the ventricular volumes change oppositely. These findings suggest a type of interventricular dependency. –