Assessment of Hemodynamic Determinants of Exercise Capacity : An Importance of Left Ventricular Early Diastolic Performance

To assess the effect of resting left ventricular (LV) diastolic function on exercise capacity, 18 patients with old myocardial infarction (mean age 61±9 yrs) underwent cardio-pulmonary stress test for measuring anaerobic threshold (AT) and left ventriculography (LVG) with simultaneous measurement of left ventricular pressure (LVP). From frame-by-frame analysis of LVG and LVP, we calculated time constant of LV pressure decay (T), normalized peak filling rate (nPFR), normalized end-diastolic compliance (dV/VdP)ed, and stiffness constant (k). T was prolonged (50±9 msec), nPFR was decreased (1.41±0.4386^<-1>) and (dV/VdP)ed was increased (0.017±0.012mmHg^<-1>). But k (0.039±0.030) showed no significant difference compared with our previously reported normal values. Although there were no significant correlations between AT and (dV/VdP)ed or k, AT had a significant negative correlation with T(r=-0.63, p<0.05), and a positive correlation with nPFR (r=0.70, p<0.05). Thus, this study suggests that the early left ventricular diastolic property but not LV compliance might play an important role for determining exercise capacity in patients with old myocardial infarction.

運動耐容能

嫌気性代謝閾値

左室拡張期特性