title: Left atrial volume as an independent predictor of exercise capacity in patients with isolated diastolic dysfunction presented with exertional dyspnea.
abstract: BACKGROUND
  Left atrial volume (LAV) and exercise capacity are important prognostic determinants of cardiovascular risk. Exercise intolerance and increased LAV are expected in patients with diastolic dysfunction. While dyspnea is the symptom reported by the patient and considered subjective, exercise capacity obtained by exercise testing provides an objective measure of cardiovascular fitness. The objective of this study is to determine the relationship between LAV index and exercise capacity in patients with isolated diastolic dysfunction who presented with exertional dyspnea.
  
  
  METHODS
  We studied consecutive patients with dyspnea who underwent treadmill exercise testing and transthoracic echocardiography on the same day. LAV was assessed using the biplane area-length method. Symptom-limited exercise testing was performed immediately after echocardiography. Patients with coronary artery disease, valvular or congenital heart disease, left ventricular systolic dysfunction, pulmonary hypertension or positive exercise test were excluded.
  
  
  RESULTS
  The study consisted of 111 patients (58.1 ± 9.2 years of age, 54.1% male, 64% hypertension, 57.7% dyslipidemia and 20.7% diabetes). The exercise duration and capacity were 6.8 ± 2.1 minutes and 7.7 ± 1.9 METs, respectively. Left ventricular ejection fraction and LAV index was 71.0 ± 5.8% and 31.4 ± 10.5 ml/m2, respectively. In multivariate analysis, age [odds ratios (OR) 0.94; 95% confidence interval (CI) 0.89-0.99], body mass index (OR 0.82, 95% CI 0.72-0.93), and LAV index (OR 0.92, 95% CI 0.87-0.97) were associated with good exercise capacity.
  
  
  CONCLUSIONS
  In patients with isolated diastolic dysfunction and exertional dyspnea, an increased LAV index, a marker of chronic diastolic dysfunction, is associated with poor exercise capacity.
authors.affiliation: Division of Cardiology, Department of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand. nithima.cha@mahidol.ac.th.
authors.forename: Nithima
authors.initials: N
authors.lastname: Ratanasit
authors.forename: Khemajira
authors.initials: K
authors.lastname: Karaketklang
authors.forename: Srisakul
authors.initials: S
authors.lastname: Chirakarnjanakorn
authors.forename: Rungroj
authors.initials: R
authors.lastname: Krittayaphong
authors.forename: Decho
authors.initials: D
authors.lastname: Jakrapanichakul
mesh_terms: D000368:Aged; D016279:Atrial Function, Left / Q000502:physiology*; D002908:Chronic Disease; D003971:Diastole / Q000502:physiology*; D004417:Dyspnea / Q000503:physiopathology*; D004452:Echocardiography / Q000379:methods*; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D011237:Predictive Value of Tests; D018570:Risk Assessment