762-1 A Study in Ventricular-Ventricular Interaction: Single Right Ventricles Compared with Systemic Right Ventricles In a Dual Chambered Circulation

Abstract

Ventricular-ventricular interaction (W) is known to occur in the normal human heart. Because a subgroup of single right ventricle pts who have undergone the Fontan procedure (F) present in ventricular failure, we compared systemic right ventricles with and without a mechanically coupled left ventricle to determine the biomechanical effects of ventricular interdependence. A magnetic resonance tagging technique which lays stripes down on the myocardium called spatial modulation of magnetization was employed to examine 18 pts with systemic right ventricles: 7 F and 11 with transposition of the great arteries who have undergone an atrial inversion operation (Alo). The systolic motion of the intersection points were tracked to determine regional twist, radial motion and finite strain analysis was applied to the grid lines to derive principle E1 strains at the atioventricular and apical short axis levels and in 4 anatomic wall regions. Strain was greatest (–0.2 ± 0.02 at the posterior wall at the atrioventricular valve) and heterogeneity of strain least (coefficient of variation 0.46 ± 0.03 at the inferior wall at the atrioventricular valve) in pts with Ala (6/8 regions). Marked differences were noted in strain distribution within a given region, from endocardium to epicardium (strain distribution across the thickness of the myocardium). and from atrioventricular valve to apex (strain distribution along the ventricular long axis) between pt subtypes and the normalleft ventricle.