Abstract 4564: Use of Adult Dyssynchrony Thresholds in Pediatric Patients Leads to a High False Positive Rate
Introduction While cardiac resynchronization therapy (CRT) has been successful in adults, translation into pediatrics is complicated. Tissue Doppler echocardiographic assessment of dyssynchrony may help identify children who will benefit from CRT. However, threshold values to diagnose dyssynchrony in pediatric patients have not been defined. We hypothesized that adult tissue Doppler dyssynchrony thresholds would not accurately apply to pediatric patients. We aimed to define new threshold values as necessary.
Methods Sixty controls with normal QRS on ECG and 2D echocardiography were enrolled with 20 subjects in each of three age groups: 0 –2, 2–10 and 10 –17 years. Four dyssynchrony parameters were quantified: septal to lateral delay (SLD), peak velocity difference (PVD), SD of the 12 segment model (TsSD), and cross-correlation delay (XCD). Published adult thresholds for each dyssynchrony parameter (60, 65, 34 and 31 msec for SLD, PVD, TsSD and XCD, respectively) were used to calculate false positive rates (i.e. the percentage of normal controls incorrectly diagnosed as dyssynchronous).
Results SLD, PVD and TsSD had high false positive rates while XCD did not (Fig A⇓). The false positive rate for XCD approached 0% with increasing age (Fig B⇓). The upper limit of normal for XCD defined by mean + 2*SD was 46, 56 and 34 msec for the 0 –2, 2–10 and 10 –17 age groups, respectively.
Conclusions Adult tissue Doppler dyssynchrony thresholds for 3 of the most commonly used parameters incorrectly diagnose 57– 85% of normal children as dyssynchronous. Cross-correlation delay shows promise in diagnosing dyssynchrony in children, and new thresholds for younger patients have been developed.