Determinants of exercise capacity in hypertensive patients: new insights from tissue Doppler echocardiography.
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.
Kim
Hyung-Kwan
HK
Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea.
Kim
Yong-Jin
YJ
Cho
Young-Seok
YS
Sohn
Dae-Won
DW
Lee
Myoung-Mook
MM
Park
Young-Bae
YB
Choi
Yun-Shik
YS
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*