Objective: Long-term preservation of ventricular function is becoming increasingly important as the survival of patients with single ventricle physiology improves. Strain and strain rate (SR) imaging is a relatively load independent measure of ventricular function. In this prospective study, we measured strain and SR pattern in a homogeneous group of infants with hypoplastic left heart (HLH).

Method: Fifteen infants (HLHS=11, unbalanced AVSD=4) underwent a sedated echocardiogram and cardiac MRI prior to the bidirectional cavopulmonary anastomosis (BCPA) at a mean of 27 ± 19 days apart. Global longitudinal (apical 4 chamber) and circumferential (basal and apical short axis) strain and SR were measured with speckle tracking imaging using commercially available software. MRI ventricular volumes and mass were indexed to body surface area.

Results: Mean age at echocardiography was 4.7 ± 2.1 months. One had severe and 3 had moderate tricuspid regurgitation. Mean strain and SR are summarized in Table 1. Apical circumferential strain and SR decreased with increasing ventricular volumes and showed significant linear correlations (Figure 1). Increased RV mass significantly correlated with decreased apical strain (r=0.68, p<0.01) and SR (r=0.7, p<0.01). RV volumes and mass had no relationship to basal circumferential or longitudinal strain or SR.

Conclusion: Apical strain and SR were the best indicators of ventricular size in infants with HLH prior to BCPA, and may provide a serial marker for which to quantify ventricular function. Further longitudinal studies are required to determine the applicability of these results to all stages of surgical palliation.