BACKGROUND

The purpose of our study was to explore the pumping mechanism of the left ventricle (LV) and to examine the role of longitudinal LV contraction in LV stroke volume (LVSV) compared to a radial LV contraction.

METHODS AND RESULTS

We examined 890 consecutive children without structural heart disease including 395 patients with a history of Kawasaki disease (KD). We measured the mitral annular plane systolic excursion (MAPSE), the LV end-diastolic and end-systolic dimension (LVDd), the LV radial wall displacement (LVRWD) and the LV stroke volume (LVSV). The LVSV was determined by the Doppler method. The z-values of MAPSE, LVDd, LVRWD and LVSV were calculated by the mean values and standard deviations (SDs) based upon BSA every 0.1 m(2) . We evaluated the relationship between the z-LVSV and the geometrical factors. The z-value of the MAPSE was the most powerful determinant for the z-values of the LVSV of all of the geometrical factors (β = 0.36, P < 0.0001). However, the z-values of the LVRWD did not contribute to those of the LVSV.

CONCLUSIONS

The longitudinal LV contraction contributes more to the LVSV than the radial LV contraction, even in subjects without heart failure. Evaluation of longitudinal LV contraction using the MAPSE z-value is useful for assessing global LV function in children with various body sizes.