Background: The univentricular heart (UVH) corrected by Fontan repair is characterized by a single dilated pumping chamber, which is both hypertrophic and hypocontractile. The complex geometrical distortion and asynchronous contraction of this organ prevents assessment of systolic and diastolic function by traditional echocardiographic procedures.
Methods: Sixteen children (10 males, 6 females) aged 12-31 years, who had undergone UVH Fontan repair were enrolled in the study. A transthoracic echocardiography was performed. Twelve different myocardial wall segments from single ventricles were studied by Doppler tissue imaging to measure peak systolic velocity (S), isovolumetric relaxation time (IRT), isovolumetric contraction time (ICT), and E'/A' ratio.
Results: S and E'/A' ratio were significantly lower in the UVH group than in controls (P < 0.01 and P < 0.05, respectively). IRT and ICT were significantly longer in UVH than in controls (P < 0.001 and P < 0.005, respectively). In the UVH, both systolic and diastolic deficits were generally registered in the apical segments and also randomly distributed between the basal and middle segments of the single ventricle.
Conclusions: It is an acknowledged fact that compared to normal children ventricular function is impaired in patients with UVH. Tissue Doppler imaging at multiple points of the single ventricle provides a complete, accurate assessment of systolic and diastolic function after Fontan repair, overcoming problems posed by geometrical distortion and limitations of conventional echocardiographic methods.