title: Left atrial function and phenotypes in asymmetric hypertrophic cardiomyopathy.
abstract: BACKGROUND
  Few studies have analyzed changes in left atrial (LA) function associated with different phenotypes of asymmetric hypertrophic cardiomyopathy (HCM). We sought to demonstrate the association of impairments in LA function with disease phenotype in patients with obstructive and nonobstructive HCM.
  
  
  METHODS
  From Stanford Cardiomyopathy Registry, we randomly selected 50 age-/sex-matched healthy controls, 35 patients with nonobstructive HCM (HCM 1), 35 patients with obstructive HCM (HCM 2), and 35 patients with obstructive HCM requiring septal reduction therapy (HCM 3). Echocardiography was performed to evaluate left ventricular (LV) strain as well as LA function including LA emptying fraction and LA strain.
  
  
  RESULTS
  The mean age was 51±14 years and 57% were male. LA volume index differed among all four predefined groups (25.6±6.7 mL/m2in controls, 32.2±13.3 mL/m2in HCM 1, 42.0±12.9 mL/m2in HCM 2, 52.4±15.2 mL/m2for HCM 3, and P<.05 all between groups). All measurement of LA function was impaired in patients with HCM than controls. Total and passive LA function was further impaired in HCM 2 or 3 compared with HCM 1, while active LA function was not different among the three groups. Among LV strains, only septal longitudinal strain differed among all groups (-18.5±1.9% in controls, -14.5±1.9% in HCM 1, -13.3±1.8% in HCM 2, -11.6±2.3% in HCM 3, and P<.05 all between groups).
  
  
  CONCLUSIONS
  LA function was impaired in patients with HCM even in minimally symptomatic nonobstructive phenotype. Total and passive LA function was further impaired in patients with obstructive HCM.
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Yukari
authors.identifier: http://orcid.org/0000-0002-8304-8194
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Wheeler
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Gherardo
authors.initials: G
authors.lastname: Finocchiaro
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Ariyama
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Marco V
authors.initials: MV
authors.lastname: Perez
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: David
authors.initials: D
authors.lastname: Liang
authors.affiliation: Stanford Cardiovascular Institute, Stanford, CA, USA.|Research Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kuznetsova
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Ingela
authors.initials: I
authors.lastname: Schnittger
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Euan
authors.initials: E
authors.lastname: Ashley
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Francois
authors.initials: F
authors.lastname: Haddad
mesh_terms: D016279:Atrial Function, Left / Q000502:physiology*; D002312:Cardiomyopathy, Hypertrophic / Q000503:physiopathology*; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D012042:Registries; D012189:Retrospective Studies
keywords: atrial function; hypertrophic cardiomyopathy; strain imaging