Effect of postural changes and isometric exercise on Doppler-derived measurements of diastolic function in normal subjects

To determine if simple maneuvers that occur in daily life, such as changes in body position and isometric handgrip exercise, affect Doppler-derived measurements of diastolic function, we studied 22 normal male subjects in the supine position at rest and during several postural manipulations and during handgrip exercise. Comparison of values obtained in the 80° upright tilt position with those obtained in the standard supine position revealed significant decreases in early diastolic flow velocity (peak E) (-25±3 percent; p<0.001), late diastolic flow velocity (peak A) (-9±3 percent; p<0.01), and the ratio of early to late flow velocities (E/A ratio) (-17±4 percent; p<0.001) and significant increases in deceleration time (+55±10 percent; p<0.001) and isovolumic relaxation time (+38±4 percent; p<0.001). Comparison of values obtained with supine isometric exercise with those obtained during the preceding supine resting state revealed significant decreases in peak E (-12±3 percent; p<0.001) and the E/A ratio (-21±4 percent; p<0.001) and significant increases in peak A (+15±4 percent; p<0.001) and isovolumic relaxation time (+16±3 percent; p<0.001). The response of Doppler-derived measurements of diastolic function to postural changes and isometric exercise is complex and multifactorial. Interpretation of these measurements must take into account changes in loading conditions.