Right ventricular function is a crucial determinant of long-term outcomes of children with heart disease. Quantification of right ventricular systolic and diastolic performance by echocardiography is of paramount importance, given the prevalence of children with heart disease, particularly those with involvement of the right heart, such as single or systemic right ventricles, tetralogy of Fallot, and pulmonary arterial hypertension. Identification of poor right ventricular performance can provide an opportunity to intervene. In this review, we will go through the different systolic and diastolic indices, as well as their application in practice. Quantification of right ventricular function is possible and should be routinely performed using a combination of different measures, taking into account each disease state. Quantification is extremely useful for individual patient follow-up. Laboratories should continue to strive to optimise reproducibility through quality improvement and quality assurance efforts in addition to investing in technology and training for new, promising techniques, such as three-dimensional echocardiography.

Background: Pulmonary insufficiency (PI) and right ventricular (RV) dysfunction are long-term complications in rTOF. We sought to investigate RV contractile reserve and changes in PI that occur during exercise in patients with repaired tetralogy of Fallot (rTOF) and the association of these changes with exercise performance using stress echocardiography. Methods: Subjects with rTOF (n = 32) and healthy controls (n=10) were prospectively enrolled and underwent rest and peak exercise echocardiograms during standard CPET protocol on cycle ergometer or treadmill. RV contractile reserve was defined as the change in RV global longitudinal strain (RVGLS) from rest to peak exercise. PI was assessed with the diastolic systolic time velocity integral ratio (DSTVI) and diastolic/systolic velocity ratio (D/S Ratio) from pulmonary artery Doppler interrogation. Exercise measures included heart rate reserve, percent-predicted maximum oxygen consumption (%mVO2), percent-predicted maximum work (%mWork) and oxygen pulse. Results: Right ventricular contractile reserve was impaired in rTOF compared to controls with a significant drop in the absolute value of RVGLS from 17% (range 8-27) at rest to 13% (range 5-28) at peak exercise. Similarly, PI decreased at peak exercise, with a drop in DSTVI and D/S ratios. Reduction in PI was directly associated with %mVO2, %mWork, and greater oxygen pulse. Heart rate reserve was directly associated with %mVO2 and %mWork. RV contractile reserve was not associated with any exercise parameters. Conclusions: Patients with rTOF have an abnormal myocardial response to exercise with impaired RV contractile reserve compared to control subjects. Heart rate reserve and reduction in PI at peak exercise are associated with better exercise performance and appear to be significant contributors to exercise performance in rTOF. Measures to improve chronotropic health in rTOF should be explored.

Exercise performance is variable and often impaired in patients with repaired tetralogy of Fallot (rTOF). We sought to identify factors associated with exercise performance by comparing high to low performers on cardiopulmonary exercise testing (CPET) in patients with rTOF. We conducted a cross-sectional study of subjects presenting for CPET who underwent echocardiograms at rest and peak exercise. Patients with pacemakers and arrhythmias were excluded. Right ventricular (RV) global longitudinal strain was used as a measure of systolic function. Pulmonary insufficiency (PI) was assessed with the diastolic systolic ratio and the diastolic systolic time-velocity integral ratio by Doppler interrogation of the pulmonary artery. CPET measures included percent-predicted maximum [Formula: see text] [Formula: see text], percent-predicted maximum work and oxygen pulse. High versus low performers were identified as those achieving [Formula: see text] of at least 80% or falling below, respectively. Differences in echocardiographic parameters from rest to peak exercise were examined using mixed-effects regression models. Compared to the low performers (n = 17), high performers (n = 12) were younger (12.8 ± 3.3 years vs. 18.3 ± 4.8 years), had normal chronotropic response (peak heart rate > 185 bpm) with greater heart rate reserve and superior physical working capacity. High performers also had a greater reduction in PI at peak exercise, despite greater PI severity at rest. Oxygen pulse was comparable between groups. For both groups, there was no association of PI severity and RV systolic function at rest with exercise parameters. There was no group difference in the magnitude of change in RV strain and diastolic parameters from rest to peak exercise. Chronotropic response to exercise appears to be an important parameter with which to assess exercise performance in rTOF. Chronotropic health should be taken into consideration in this population, particularly given that RV function and PI severity at rest were not associated with exercise performance.

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ObjectiveWe sought to determine how sex and dexrazoxane therapy influence cardiac remodelling in children with sarcoma receiving high-dose doxorubicin.MethodsIn a retrospective cohort of 85 children with sarcoma receiving high-dose doxorubicin, echocardiography measures prior to, early after (within 6 months of doxorubicin completion) and 1 – 2 years after doxorubicin completion were quantified. At each follow-up visit, multivariable, propensity-adjusted linear regression models evaluated dexrazoxane’s effects on changes in left ventricular (LV) shortening fraction (SF), structure, strain and wall stress for subgroups divided by sex. Likelihood ratio tests assessed the interaction between sex and dexrazoxane in determining these changes.ResultsEarly after doxorubicin completion, males not treated with dexrazoxane (n = 15) developed increased cavity size and diminished circumferential strain; females (n = 8) developed diminished SF and strain indices, and increased cavity size and wall stress. With dexrazoxane, males (n = 33) demonstrated less deterioration in circumferential strain by 3.4% (95% CI 0.01 to 6.8), and females (n = 29) demonstrated less reduction in SF by 5.7% (95% CI 2.1 to 9.3), and had mitigation of increases in cavity size and wall stress. In interaction analyses, females had greater protection with dexrazoxane with regard to SF (p = 0.019) and cavity size in diastole (p = 0.002) and systole (p ≤ 0.001). These findings largely persisted 1 – 2 years after doxorubicin therapy.ConclusionsEarly, sustained alterations in LV structure and function occur in children with sarcoma after high-dose doxorubicin, with adverse changes and protective effects of dexrazoxane more pronounced in females as compared with males. Dexrazoxane may have sex-specific cardioprotective effects.