title: Occult cardiac contractile dysfunction in dystrophin-deficient children revealed by cardiac magnetic resonance strain imaging.
abstract: BACKGROUND
  Duchenne muscular dystrophy (DMD) is an inherited disease characterized by early onset of skeletal muscle degeneration and progressive weakness. Although dilated cardiomyopathy may occur during adolescence, it is often undetected early in its course because of physical inactivity and generalized debilitation. The purpose of this study was to apply the technique of cardiac magnetic resonance (CMR) tagging to detect occult cardiac dysfunction in young subjects with DMD by measuring myocardial strain and torsion.
  
  
  RESULTS
  Thirteen DMD pediatric subjects without clinically apparent heart disease and 9 age-matched healthy males were recruited. Each was scanned on a 1.5-T clinical scanner to acquire contiguous short-axis planes from the apex to the mitral valve plane and then 3 tagged images at base, midventricle, and apex. Global and segmental myocardial net twist and circumferential strain were computed with the use of 2D homogeneous strain analysis. Ventricular torsion was computed by normalizing net twist by the distance from apex to mitral valve plane. DMD patients exhibited normal left ventricular volumes and ejection fractions but manifested reduced midventricular and basal cross-sectional global circumferential strain compared with the reference group (P<0.005). These alterations also appeared in segmental analyses in the septal, anterior, lateral, and inferior walls (P<0.05).
  
  
  CONCLUSIONS
  In patients predisposed to cardiomyopathies because of dystrophinopathy, occult regional cardiac dysfunction can be diagnosed with CMR tagging. This method of strain imaging analysis may offer a sensitive approach for delineating the presence and progression of cardiovascular disease and for assessing therapies designed to modulate the onset and course of heart failure.
authors.affiliation: Department of Medicine, Washington University School of Medicine, St Louis, MO, USA.
authors.forename: M W
authors.initials: MW
authors.lastname: Ashford
authors.forename: W
authors.initials: W
authors.lastname: Liu
authors.forename: S J
authors.initials: SJ
authors.lastname: Lin
authors.forename: P
authors.initials: P
authors.lastname: Abraszewski
authors.forename: S D
authors.initials: SD
authors.lastname: Caruthers
authors.forename: A M
authors.initials: AM
authors.lastname: Connolly
authors.forename: X
authors.initials: X
authors.lastname: Yu
authors.forename: S A
authors.initials: SA
authors.lastname: Wickline
mesh_terms: D002648:Child; D016189:Dystrophin / Q000172:deficiency*; D005541:Forced Expiratory Volume; D006321:Heart / Q000502:physiology / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008279:Magnetic Resonance Imaging; D020388:Muscular Dystrophy, Duchenne / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D009200:Myocardial Contraction / Q000502:physiology*; D009206:Myocardium / Q000473:pathology; D012016:Reference Values; D014102:Torsion Abnormality
chemical_list: D016189:Dystrophin