title: Determinants of exercise capacity in hypertensive patients: new insights from tissue Doppler echocardiography.
abstract: BACKGROUND
  Determinants of exercise capacity have not been clearly defined in hypertensive patients. Doppler tissue imaging (DTI), a recently developed echocardiographic modality, is useful for evaluating left ventricular (LV) function regardless of loading conditions. The present study was performed to identify the determinants of exercise capacity in hypertensive patients using DTI.
  
  
  METHODS
  We studied 48 hypertensive patients (26 men; mean age, 57 +/- 9 years) with normal LV ejection fraction (>50%). Conventional echocardiographic indexes were measured before and after symptom-limited treadmill exercise. Also, longitudinal systolic (S(L)') and diastolic myocardial velocities (E(L)' and A(L)') and radial velocities (S(R)', E(R)', A(R)') were measured using DTI with the sample volume at the LV basal posterior wall.
  
  
  RESULTS
  Mean exercise time was 525 +/- 135 sec. Mean LV ejection fraction was 61% +/- 6%. Mean LV mass index was 110.9 +/- 24.4 g/m(2). On univariate analysis, S(L)', E(L)', A(L)' and percentage increase of S(R)' velocity after exercise showed significant correlation with exercise time. However, only E(L)' and percentage increase of S(R)' remained significant after multivariate analysis.
  
  
  CONCLUSIONS
  Left ventricular contractile reserve and relaxation property are important cardiac factors determining exercise capacity. Early diastolic longitudinal myocardial velocity might be useful for identifying hypertensive patients with poor exercise capacity.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea.
authors.forename: Hyung-Kwan
authors.initials: HK
authors.lastname: Kim
authors.forename: Yong-Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Young-Seok
authors.initials: YS
authors.lastname: Cho
authors.forename: Dae-Won
authors.initials: DW
authors.lastname: Sohn
authors.forename: Myoung-Mook
authors.initials: MM
authors.lastname: Lee
authors.forename: Young-Bae
authors.initials: YB
authors.lastname: Park
authors.forename: Yun-Shik
authors.initials: YS
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D015150:Echocardiography, Doppler / Q000379:methods*; D005080:Exercise Test / Q000379:methods; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016277:Ventricular Function, Left / Q000502:physiology*