title: Left atrial remodelling in mitral regurgitation--methodologic approach, physiological determinants, and outcome implications: a prospective quantitative Doppler-echocardiographic and electron beam-computed tomographic study.
abstract: OBJECTIVE
  To define accurate and normal range of echocardiographic left atrial (LA) volume measurement and to assess the prevalence, determinants, and outcome implications of LA enlargement in mitral regurgitation (MR).
  
  
  RESULTS
  We prospectively compared LA volume obtained simultaneously by electron beam-computed tomography (EBCT) and by four echocardiographic methods in 33 test patients. Accurate echocardiographic LA volume measurements were obtained only by biplane area-length method with vertical longitudinal-length (r = 0.95, P < 0.0001; 145 +/- 57 vs. 143 +/- 55 mL, P = 0.57). Using this method, the normal range in 100 normal subjects, the physiological determinants and outcome implications of LA enlargement in 320 patients with organic MR were analysed. In normal subjects, indexed to body surface area, LA index (27 +/- 6 mL/m(2)) was not influenced by age or gender and values > or = 40 mL/m(2) were beyond the upper limit of normal. In MR, the most powerful determinants of LA enlargement were higher regurgitant volume (RVol) and atrial fibrillation (AF) (P < 0.0001), followed by older age, female gender, higher left ventricular end-systolic volume, and mass (all P < 0.001). After diagnosis in sinus rhythm, LA index > or = 40 mL/m(2) predicted superiorly and independently to LA diameter the occurrence of AF [adjusted RR 1.48 (1.06-2.16), P < 0.01] and the combined endpoint of death or need for mitral surgery [adjusted RR 1.61 (1.3-2.0), P < 0.0001].
  
  
  CONCLUSIONS
  LA remodelling can be accurately assessed by echocardiography and LA index > or = 40 mL/m(2) is beyond the normal range. In organic MR, higher LA index is the combined result of multiple physiological effects, provides independent prognostic information, and therefore should be part of a comprehensive echocardiographic examination.
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: David
authors.initials: D
authors.lastname: Messika-Zeitoun
authors.forename: Michael
authors.initials: M
authors.lastname: Bellamy
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Avierinos
authors.forename: Jerome
authors.initials: J
authors.lastname: Breen
authors.forename: Christian
authors.initials: C
authors.lastname: Eusemann
authors.forename: Andrea
authors.initials: A
authors.lastname: Rossi
authors.forename: Thomas
authors.initials: T
authors.lastname: Behrenbeck
authors.forename: Christopher
authors.initials: C
authors.lastname: Scott
authors.forename: Jamil A
authors.initials: JA
authors.lastname: Tajik
authors.forename: Maurice
authors.initials: M
authors.lastname: Enriquez-Sarano
mesh_terms: D000368:Aged; D016279:Atrial Function, Left / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D015331:Cohort Studies; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006325:Heart Atria / Q000648:ultrastructure; D006801:Humans; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D014055:Tomography, Emission-Computed / Q000379:methods; D014463:Ultrasonography