P741Significant prolongation of isovolumic time intervals with preservation of systolic and diastolic time in children with hypoplastic left heart syndrome compared to normal children

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Purpose: Age and heart rate related tissue Doppler derived time intervals in healthy children have been published. Staged palliation for hypoplastic left heart syndrome (HLHS) subjects the systemic right ventricle to different loading conditions and heart rates. We studied the changes in tissue Doppler time intervals in patients with HLHS at different stages of surgical palliation.Methods: Tissue Doppler images were prospectively acquired as part of a larger study of patients with HLHS. 90 echocardiographic studies were performed in 69 patients, with 76 studies judged of sufficient quality for analysis. Isovolumic contraction (IVCT) and relaxation times (IVRT) as well as ejection time (ET) were measured at the lateral tricuspid annulus. Filling time (RR minus IVCT+ET+IVRT), systolic (ET+IVCT) and diastolic time (IVRT+filling time) were then calculated. Isovolumic times were corrected for the RR interval as previously described. All indices were converted to z-scores using normal paediatric tricuspid annulus TDI data.Results: On ANOVA analysis, IVCT and IVRT were significantly prolonged compared to both normal ventricles at all surgical stages. Heart rate corrected ejection, systolic and diastolic times as well as the systolic/diastolic ratio were not significantly different from normal. Figure 1 shows the significantly prolonged IVCT (with ejection and systolic times) using z-scores from the lateral tricuspid valve in normal children.Conclusions: Isovolumic times are significantly prolonged in patients with HLHS at through all stages of surgical palliation. The exact mechanism of this and whether this reflects adaption or maladaption requires further study.

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