Worsening of left ventricular diastolic dysfunction during exercise causesdecreased exercise tolerance in hypertension

Background: Exercise tolerance is reduced in hypertension. Hypertension aff ects left ventricular (LV) diastolic filling by causing abnormal relaxation and decreasing compliance. Hypothesis: This study was designed to determine whether worsening of LV di astolic dysfunction during exercise causes decreased exercise tolerance in hypertension. Methods: Left ventricular diastolic filling parameters were examined at mit ral valve by Doppler echocardiography at rest and at peak exercise in hyper tensive patients and were compared with those of age- and gender-matched no rmotensive individuals. Treadmill exercise stress test was performed accord ing to the Bruce protocol and the exercise time was recorded. Results: Exercise time was significantly shorter in the hypertensive group than that in the normotensive group (320 +/- 29 vs. 446 +/- 38 s, p 0.03). The hypertensive group demonstrated abnormal relaxation pattern of diastoli c mitral inflow at rest, which became pseudonormal at peak exercise (E/A ve locity ratio, rest 0.86 +/- 0.06 vs, exercise 1.19 +/- 0.09, p<0.001). The diastolic mitral inflow pattern remained normal at peak exercise in the nor motensive group. The deceleration time and the pressure half time of early mitral inflow at peak exercise were significantly shorter in the hypertensi ve group than those in the normotensive group (deceleration time, 182 + 20 vs. 238 +/- 22 ms, p 0.02: pressure half time, 54 +/- 5 vs. 70 +/- 12 ms, p 0.01). Conclusions: This study demonstrates that reduced exercise tolerance in hyp ertension is associated with worsening of diastolic dysfunction during exer cise consistent with an increase in left atrial pressure.