Dr Martin Koestenberger has substantially added to the literature regarding echocardiographic assessment of ventricular function in children with congenital heart disease. We were therefore much encouraged by his positive comments and thoughtful questions in relation to our report “Exercise Echocardiography Demonstrates Biventricular Systolic Dysfunction and Reveals Decreased Left Ventricular Contractile Reserve in Children after Tetralogy of Fallot Rrepair.”
Dr Koestenberger requests that we provide more information about the modified version of tricuspid annular plane systolic excursion (right ventricular [RV] long-axis fractional shortening) and mitral annular plane systolic excursion (left ventricular long-axis fractional shortening) described in our report. Specifically, he is interested in the range of these measurements in healthy children. Means and SDs for these data are documented in Table 3 of our report. However, we are happy to provide additional information below (see Table 1 ).
|LV LAX FS at rest in controls (%) ( n = 44)||RV LAX FS at rest in controls (%) ( n = 44)|
Dr Koestenberger also suggested that we compare the tricuspid annular peak systolic velocities recorded in our study subjects with published normal pediatric values. To do so, we revisited our raw data, cross-referencing each subject’s age and measured resting RV S′ against the normative data provided in tables published by Koestenberger et al ., which were derived from 860 healthy children. A comparison is shown in Table 2 . In general (for both the children with tetralogy of Fallot and the healthy controls), our measurements of RV S′ were lower than the values reported by Koestenberger et al . in healthy children. It seems most likely that this discrepancy is due to the use of different ultrasound systems and software packages (we used the Vivid 7 [GE Healthcare, Little Chalfont, United Kingdom], whereas Koestenberger et al .’s normative data were obtained with an iE33 [Phillips Medical Systems, Andover, MA]). In their study, Koopman et al . found that comparison of color tissue Doppler measurements made with machines from different manufacturers is particularly problematic. In addition, there may have been interobserver variability in technique. These issues are one reason our study design included a comparative control group and why when preparing the report, we opted not to compare our results to published normative data. Bearing such caveats in mind, when the comparison is made, it can seen that the vast majority of our patients with tetralogy of Fallot demonstrated significantly reduced resting RV S′, with 93% falling >3 SDs below their age-predicted values ( Table 2 ).