BACKGROUND: Left ventricular(LV) adaptation to high blood pressure produces unique geometrical change, which is closely associated with the prognosis and quality of life in hypertensive patients irrespective of the presence of LV hypertrophy. Exercise capacity assessed by treadmill test(TMT) can provide prognostic information in these patients. We evaluated relationship between LV geometry and exercise capacity in hypertensive patients with isolated diastolic dysfunction. METHODS: According to the echocardiographic results, 109 patients with essential hypertension, who performed TMT for estimating exercise capacity, were classified as having normal LV geometry (NG, n=40) or concentric LV geometry (CG, n=69). Patients with concentric LV geometry were categorized into moderate (n=55) or marked (n=14) CG on the basis of the criteria previously reported. Conventional echocardiographic and tissue Doppler imaging indices were obtained with standard techniques. RESULTS: There were no differences in age, gender and resting heart rate between NG and CG. Maximal exercise time was longer in NG than in CG (617.3+/-131.5 vs. 566.0+/-155.0 seconds, p<0.05). Late diastolic mitral annular velocity (AO) exhibited a significant correlation with maximal exercise time in moderate and marked CG (r=0.30 and 0.56, both p<0.05), which remained significant after multivariate linear regression analysis with variables such as age, LV mass, early to late mitral inflow ratio, AO velocity, LV ejection fraction and left atrial size, whereas such a correlation could not be found in NG. CONCLUSION: Since exercise performance decreases when there is LV concentric remodeling, LV geometry needs to be considered in the assessment of exercise capacity in patients with essential hypertension and isolated diastolic dysfunction. Atrial systolic function plays a crucial role in maintaining exercise capacity in these patients, especially in those with increased LV concentricity.