Utility of Doppler tissue imaging-derived indices in identifying subclinical systolic ventricular dysfunction in children with restrictive cardiomyopathy

Restrictive cardiomyopathy (RCM) is characterized by irreversible diastolic dysfunction with preserved systolic function. The aim of this study was to investigate the presence of impaired ventricular contractility even in the presence of normal ejection fraction (EF) in children with RCM. Longitudinal Doppler tissue velocities were obtained from apical 4-chamber view at three locations-the left-ventricular (LV) lateral wall, the septum, and the right ventricle-in 8 children age 3-17 years old with RCM who had LV EF >55%. Peak systolic velocity (S0), acceleration during isovolumic contraction (IVA), and myocardial performance index (MPI) were measured. Data from the RCM group were compared with those from 24 age-and sex-matched controls. Both S0 and IVA were markedly lower at the septum (S0 6.2 ± 1.7 vs. 9.2 ± 1.6, P<0.001; IVA 1.8 ± 0.5 vs. 3.9 ± 1.5, P<0.001). MPI, a measure of both diastolic and systolic function, was statistically significantly greater in the RCM group at all 3 locations (P < 0.005). S0 and IVA identify global subclinical systolic dysfunction in RCM with normal EF. These findings suggest that pre-ejection abnormality and subclinical systolic dysfunction coexist with diastolic dysfunction in children with RCM.