CORRESPONDENCE Biventricular Systolic Function Impairment in Children after Tetralogy of Fallot Repair To the Editor: I read with interest the article ‘‘Exercise Echocardiography Demonstrates Biventricular Systolic Dysfunction and Reveals Decreased Left Ventricular Contractile Reserve in Children after Tetralogy of Fallot Repair’’ by Roche et al.1 In my opinion, this is an excellent report describing that exercise echocardiography provides additional information on biventricular abnormalities in postsurgical children with tetralogy of Fallot (TOF), which also reveals abnormal left ventricular (LV) excitation-contractile coupling. I want to highlight that Roche et al. for the first time showed early abnormalities of biventricular systolic function and markedly reduced LV contractile reserve in asymptomatic children with TOF repair. In addition, I agree with the authors’ statement that there is a lack of data addressing the relation between right ventricular (RV) long-axis function, RV-LV interaction, and the presence of clinical symptoms in children with repaired TOF. The authors stated that Doppler tissue imaging parameters, such as tricuspid annular peak systolic velocity (S0 ) and mitral annular peak systolic velocity (Sm), provided useful information about systolic RV function in their children with TOF during resting and exercise echocardiography. They described a modified measurement of tricuspid annular plane systolic excursion and mitral tricuspid annular plane systolic excursion, expressed as percentage changes in length from diastole to systole (long-axis fractional shortening [FS]), which they found useful for the detection of an impaired myocardial response in both ventricles in children with repaired TOF.1 I invite the authors to provide more information about this specific calculation for the audience of JASE, in particular about normal ranges of the percentage changes in healthy children. In imaging guidelines for patients with TOF, impairment of RV Doppler tissue imaging parameters and M-mode parameters in comparison with available normative values is described as useful for the detection of RV systolic dysfunction.2 It would therefore also be of interest for to readers how Doppler tissue imaging parameters in patients with repaired TOF in their study1 compare with available age-dependent parameters. A comparison of their S0 and Sm data with available normal S0 and Sm Z scores,3,4 in my opinion, will improve the statistical power of their analysis. Roche et al. also demonstrated marked RV outflow tract (RVOT) systolic dysfunction in children with repaired TOF using an innovative parameter, RVOT FS. Their findings significantly add to the developing knowledge about the key role of RVOT function in global normal RV function. May I ask if the authors agree with my suggestion that in addition to the measured RVOT FS, a determination of RVOT systolic excursion, when compared with available normative values,5 will have a beneficial effect in determining impaired RVOT systolic function in patients with repaired TOF? I want to thank the authors for addressing the need for a careful and systematic evaluation of RV functional parameters and cardiac biomarkers in patients with TOF early after surgical repair, and I strongly support their notion that exercise echocardiography provides important additional information about systolic biventricular function and ventricular-ventricular interaction.

Martin Koestenberger, MD Division of Pediatric Cardiology, Department of Pediatrics, Medical University Graz, Graz, Austria

REFERENCES 1. Roche SL, Grosse-Wortmann L, FriedbergMK, Redington AN, Stephens D, Kantor PF. Exercise echocardiography demonstrates biventricular systolic dysfunction and reveals decreased left ventricular contractile reserve in children after tetralogy of Fallot repair. J Am Soc Echocardiogr 2015;28:294301. 2. Valente AM, Cook S, Festa P, Ko HH, Krishnamurthy R, Taylor AM, et al. Multimodality imaging guidelines for patients with repaired tetralogy of Fallot: a report from the American Society of echocardiography developed in collaboration with the Society for Cardiovascular Magnetic Resonance and the Society for Pediatric Radiology. J Am Soc Echocardiogr 2014;27:111-41. 3. Koestenberger M, Nagel B, Ravekes W, Avian A, Heinzl B, Cvirn G, et al. Reference values of tricuspid annular peak systolic velocity in healthy pediatric patients, calculation of Z score, and comparison to tricuspid annular plane systolic excursion. Am J Cardiol 2012;109:116-21. 4. Koestenberger M, Nagel B, Ravekes W, Avian A, Heinzl B, Fritsch P, et al. Left ventricular long-axis function: reference values of the mitral annular plane systolic excursion (MAPSE) in 558 healthy children and calculation of Z-score values. Am Heart J 2012;164:125-31. 5. Koestenberger M, Ravekes W, Nagel B, Avian A, Heinzl B, Cvirn G, et al. Reference values of the right ventricular outflow tract systolic excursion in 711 healthy children and calculation of Z-score values. Eur Heart J Cardiovasc Imaging 2014;15:980-6. http://dx.doi.org/10.1016/j.echo.2015.01.004

Comments on the Assessment of Biventricular Function in Children after Tetralogy of Fallot Repair To the Editor: 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.’’1 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.1 However, we are happy to provide additional information below (see Table 1). Dr Koestenberger also suggested that we compare the tricuspid annular peak systolic velocities recorded in our study subjects with published normal pediatric values.2 To do so, we revisited our raw data, cross-referencing each subject’s age and measured resting RV S0 against the normative data provided in tables published by Koestenberger et al.,2 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 S0 were lower than the values reported by Koestenberger et al.2 in healthy children. It seems most likely that this discrepancy is due to the use of different ultrasound 495