Evaluation of left ventricular reserve in left ventricular diseases: non-invasive analysis of its determinants by dynamic exercise echocardiography.

To analyze the determinants of left ventricular (LV) reserve non-invasively, LV echocardiograms were taken during ergometer exercise in 52 LV disease patients (19 with hypertension [HT], 22 with aortic regurgitation [AR] and 11 with dilated cardiomyopathy [DCM] with various severities. In mild cases [HT], at exercise, fractional shortening (FS) increased, and at higher-grade exercise, an increase of LV enddiastolic diameter (Dd) was added to more increase of FS, to increase stroke volume (SV). In moderately severe cases [HT, AR or DCM], FS did not change or decreased at exercise. In severe cases [AR or DCM], FS was low at rest, and at exercise decreased further with an increase of LV systolic stress and no significant increase of Dd, resulting in a decrease of SV. The responses of LV parameters in volume-overload (AR) or dilated myocardial (DCM) hearts were poorer than in pressure-overload (HT) hearts, in moderately severe cases. In conclusion, exercise echocardiography can show non-invasively that the interrelationship among the determinants of LV reserve is different by the severities and the types of LV diseases, and this method is useful, especially in discriminating mild cases objectively.