title: Increase in left ventricular torsion-to-shortening ratio in children with valvular aortic stenosis.
abstract: Perfusion of left ventricular (LV) subendocardium in valvular aortic stenosis (AS) patients is impaired. It was expected that this may lead to a reduction of subendocardial fiber contraction and, consequently, to an increase of LV torsion per amount of ejection. Using MR tagging (MRT), it was investigated whether the torsion-to-shortening ratio (TSR) is elevated in valvular AS patients. Six asymptomatic children with valvular AS were investigated using echo Doppler, ECG, exercise test, and MRT. LV torsion and natural strain of the inner diameter were determined from measured tag displacements in two short-axis slices of the LV. In all AS patients TSR was approximately 40% increased (0.62 +/- 0.04 rad; mean +/- SD) as compared to pediatric (0.44 +/- 0.08 rad; n=5) and adult controls (0.46 +/- 0.08 rad; n=9), indicating subendocardial contractile dysfunction. With other techniques hitherto used this type of dysfunction could not be detected.
authors.affiliation: Department of Pediatrics, Cardiovascular Research Institute Maastricht, Maastricht University and University Hospital, Maastricht, The Netherlands. T.Delhaas@fys.unimaas.nl
authors.forename: Tammo
authors.initials: T
authors.lastname: Delhaas
authors.forename: Jiska
authors.initials: J
authors.lastname: Kotte
authors.forename: Annet
authors.initials: A
authors.lastname: van der Toorn
authors.forename: Gabriël
authors.initials: G
authors.lastname: Snoep
authors.forename: Frits W
authors.initials: FW
authors.lastname: Prinzen
authors.forename: Theo
authors.initials: T
authors.lastname: Arts
mesh_terms: D000293:Adolescent; D001024:Aortic Valve Stenosis / Q000473:pathology*; D002648:Child; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D018709:Statistics, Nonparametric; D014102:Torsion Abnormality; D016277:Ventricular Function, Left