title: Investigation of global and regional myocardial mechanics with 3-dimensional speckle tracking echocardiography and relations to hypertrophy and fibrosis in hypertrophic cardiomyopathy.
abstract: BACKGROUND
  In hypertrophic cardiomyopathy (HCM), heterogeneous myocardial hypertrophy and fibrosis are responsible for abnormalities of left ventricular (LV) function. We aimed to characterize LV global and regional myocardial mechanics in HCM, according to segmental hypertrophy and fibrosis.
  
  
  RESULTS
  Fifty-nine patients with HCM underwent standard echocardiography, 3-dimensional speckle tracking echocardiography, and cardiac magnetic resonance with late gadolinium enhancement (LGE); all 3 tests were <24 hours apart. Longitudinal, circumferential, and area strains were investigated according to the extent of LGE (no LGE, LGE<10%, and LGE≥10%), segmental thickness (≥15 versus <15 mm), and segmental LGE (LGE versus non-LGE). Attenuated global longitudinal strain showed association with extent of hypertrophy (indexed LV mass, r=0.32, P=0.01; maximum LV wall thickness, r=0.34, P=0.009; number of segments≥15 mm, r=0.44, P<0.001), whereas enhanced global circumferential strain was correlated to LV global functional parameters (indexed end-systolic volume, r=0.47, P<0.001; ejection fraction, r=-0.75, P<0.001). Parameters of global myocardial mechanics showed no association with the extent of LGE; in contrast, the extent of LGE was associated with the extent of hypertrophy. All 3 deformation parameters were attenuated both in segments≥15 mm in thickness and in those with LGE; adjusted analysis demonstrated that segmental presence of LGE was associated with additional attenuation in myocardial deformation.
  
  
  CONCLUSIONS
  Both hypertrophy and fibrosis contribute to regional impairment of myocardial shortening in HCM. The extent of hypertrophy is the primary factor altering global myocardial mechanics. Circumferential myocardial shortening seems to be directly involved in preservation of LV systolic performance in HCM.
authors.affiliation: Hypertrophic Cardiomyopathy Center and Cardiovascular Imaging and Hemodynamic Laboratory, Tufts Medical Center, Boston, MA.
authors.forename: Jose Angel
authors.initials: JA
authors.lastname: Urbano-Moral
authors.forename: Ethan J
authors.initials: EJ
authors.lastname: Rowin
authors.forename: Martin S
authors.initials: MS
authors.lastname: Maron
authors.forename: Andrew
authors.initials: A
authors.lastname: Crean
authors.forename: Natesa G
authors.initials: NG
authors.lastname: Pandian
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D016009:Chi-Square Distribution; D003287:Contrast Media; D019560:Echocardiography, Three-Dimensional; D005260:Female; D005355:Fibrosis; D019786:Gadolinium DTPA; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D016014:Linear Models; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009206:Myocardium / Q000473:pathology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D016277:Ventricular Function, Left
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
keywords: cardiomyopathy, hypertrophic; echocardiography; magnetic resonance imaging