title: Left atrial structure and function in atrial fibrillation: ENGAGE AF-TIMI 48.
abstract: OBJECTIVE
  The complex relationship between left atrial (LA) structure and function, electrical burden of atrial fibrillation (AF) and stroke risk is not well understood. We aimed to describe LA structure and function in AF.
  
  
  RESULTS
  Left atrial structure and function was assessed in 971 subjects enrolled in the echocardiographic substudy of ENGAGE AF-TIMI 48. Left atrial size, emptying fraction (LAEF), and contractile function were compared across AF types (paroxysmal, persistent, or permanent) and CHADS2 scores as an estimate of stroke risk. The majority of AF patients (55%) had both LA enlargement and reduced LAEF, with an inverse relationship between LA size and LAEF (R = -0.57, P < 0.001). With an increasing electrical burden of AF and higher CHADS2 scores, LA size increased and LAEF declined. Moreover, 19% of AF subjects had impaired LAEF despite normal LA size, and LA contractile dysfunction was present even among the subset of AF subjects in sinus rhythm at the time of echocardiography.
  
  
  CONCLUSIONS
  In a contemporary AF population, LA structure and function were increasingly abnormal with a greater electrical burden of AF and higher stroke risk estimated by the CHADS2 score. Moreover, LA dysfunction was present despite normal LA size and sinus rhythm, suggesting that the assessment of LA function may add important incremental information in the evaluation of AF patients.
  
  
  BACKGROUND
  http://www.clinicaltrials.gov; ID = NCT00781391.
authors.affiliation: Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA.
authors.forename: Deepak K
authors.initials: DK
authors.lastname: Gupta
authors.affiliation: Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA.
authors.forename: Amil M
authors.initials: AM
authors.lastname: Shah
authors.affiliation: TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Giugliano
authors.affiliation: TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Christian T
authors.initials: CT
authors.lastname: Ruff
authors.affiliation: TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Elliott M
authors.initials: EM
authors.lastname: Antman
authors.affiliation: TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Laura T
authors.initials: LT
authors.lastname: Grip
authors.affiliation: TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Naveen
authors.initials: N
authors.lastname: Deenadayalu
authors.affiliation: TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Elaine
authors.initials: E
authors.lastname: Hoffman
authors.affiliation: Daiichi-Sankyo Pharma Development, Edison, NJ, USA.
authors.forename: Indravadan
authors.initials: I
authors.lastname: Patel
authors.affiliation: Daiichi-Sankyo Pharma Development, Edison, NJ, USA.
authors.forename: Minggao
authors.initials: M
authors.lastname: Shi
authors.affiliation: Daiichi-Sankyo Pharma Development, Edison, NJ, USA.
authors.forename: Michele
authors.initials: M
authors.lastname: Mercuri
authors.affiliation: Kerckhoff Clinic Nauheim, Bad Nauheim, Germany.
authors.forename: Veselin
authors.initials: V
authors.lastname: Mitrovic
authors.affiliation: TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Eugene
authors.initials: E
authors.lastname: Braunwald
authors.affiliation: Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA ssolomon@rics.bwh.harvard.edu.
authors.forename: Scott D
authors.initials: SD
authors.lastname: Solomon
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology*; D016279:Atrial Function, Left / Q000502:physiology*; D004311:Double-Blind Method; D004452:Echocardiography; D005260:Female; D006325:Heart Atria / Q000473:pathology; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011725:Pyridines / Q000008:administration & dosage; D013318:Stroke Volume / Q000502:physiology; D013844:Thiazoles / Q000008:administration & dosage; D016277:Ventricular Function, Left / Q000502:physiology; D020257:Ventricular Remodeling / Q000502:physiology
chemical_list: D000925:Anticoagulants; D011725:Pyridines; D013844:Thiazoles; C552171:edoxaban
keywords: Atrial fibrillation; ENGAGE AF-TIMI 48; Echocardiography; Left atrium; Stroke