title: Influence of age on left atrial appendage function in patients with nonvalvular atrial fibrillation.
abstract: BACKGROUND
  Age is an independent risk factor for thromboembolism in nonvalvular atrial fibrillation (NVAF). An association between low left atrial appendage (LAA) Doppler velocities and thromboembolic risk in NVAF has been reported.
  
  
  OBJECTIVE
  The study was undertaken to identify age-related differences in LAA function that may explain the higher thromboembolic rates in older patients with NVAF.
  
  
  METHODS
  Forty-two consecutive patients (age 69+/-2 years [range 42-92], 24 [57%] men) with NVAF underwent transthoracic and transesophageal echocardiography. The following were compared in 22 patients younger and 20 older than 70 years: left ventricular (LV) diameter, mass and ejection fraction, left atrial (LA) diameter and volume, LAA area and volume, LAA peak emptying (PE) and peak filling (PF) velocities, presence and severity of spontaneous echo contrast (SEC) and mitral regurgitation (MR).
  
  
  RESULTS
  Left atrial diameter (4.6+/-0.1 vs. 4.5+/-0.2 cm), LA volume (105+/-10 vs. 92+/-8 ml), LAA area (6.8+/-0.6 vs. 5.2+/-0.8 cm2), and LAA volume (5.6+/-0.9 vs. 3.9+/-1.0 ml) were similar (p>0.05) in both groups. Older patients had lower LAA PE (26+/-2 vs. 34+/-3 cm/s, p = 0.02) and PF (32+/-2 vs. 41+/-4 cm/s, p = 0.04) velocities, lower LV mass (175+/-13 vs. 234+/-21 gm, p = 0.02), higher relative wall thickness (0.52+/-0.02 vs. 0.43+/-0.03, p = 0.02), smaller LV diastolic diameter (4.3+/-0.1 vs. 5.2+/-0.2 cm, p < 0.001), and higher LV ejection fraction (62+/-2 vs. 55+/-2%, p = 0.025). Frequency and severity of SEC and MR were similar in both groups. Multivariate analysis identified older age as the only significant predictor of reduced LAA velocities.
  
  
  CONCLUSIONS
  Compared with younger patients, older patients with NVAF have lower LAA velocities despite higher LV ejection fraction, smaller LV size, and similar LA and LAA volumes. These findings may explain the higher thromboembolic rates in older patients with NVAF.
authors.affiliation: Division of Cardiology, Echocardiography Laboratory, Albert Einstein College of Medicine, Bronx, New York 10461-2373, USA.
authors.forename: A
authors.initials: A
authors.lastname: Ilercil
authors.forename: J
authors.initials: J
authors.lastname: Kondapaneni
authors.forename: A
authors.initials: A
authors.lastname: Hla
authors.forename: J
authors.initials: J
authors.lastname: Shirani
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D020517:Atrial Appendage / Q000503:physiopathology*; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016279:Atrial Function, Left; D001783:Blood Flow Velocity; D004452:Echocardiography; D017548:Echocardiography, Transesophageal; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013923:Thromboembolism / Q000453:epidemiology* / Q000503:physiopathology