Strain and Torsion Analysis of Left Ventricular Using Tissue Tracking to Evaluate Deterioration of Ventricular Function as MR Marker in Patients with Repaired Fontan

At present, cardiovascular magnetic resonance (CMR) has emerged as the gold standard for the quantification of ventricular volume and ejection fraction in repaired Fontan patients [1]. However, left ventricle ejection fraction (LVEF) reflects the geometric change of LV, but not the contractile function of the myocardium [2]. Strain and torsion are new MRI markers to detect myocardial deformation using balanced steady state free precession (b-SSFP) cine imaging in CMR. Myocardial Strain has been shown as an earlier marker of contractile dysfunction than EF and a subclinical sign of heart muscle cells [3,4]. Torsion as a measurement of myocardial afterload, wall and fiber stresses is an important determinant of ventricular function and hypertrophy. Ventricular twist mechanics hold promise for better understanding mechanisms of ventricular dysfunction [5]. To best our acknowledge, There were much fewer data about the comparison between the prognostic value of perioperative NT-proBNP levels and MRI quantitative indexes in children after surgical repair of CHD. The study is to compare cardiac strains and torsion among the repaired Fontan patients with normal and abnormal NT- proBNP levels as well as healthy controls. We hypothesized that the global ventricular strain and torsion could be as MRI quantitative indexes for evaluation of deterioration of ventricular function in patients with repaired Fontan.