A total of 78 children with congenital heart disease performed CPET. Two children had to be excluded due to monitoring equipment failure (defect of heart rate sensor, data not stored and displayed in software) resulting in 97% technically flawless tests. 12 children were excluded from data analysis as they did not meet the exhausting criteria (peak HR ≥ 195/min, and/or RER at \(\dot_peak\) ≥ 1.0) because of patient imminent motivational reasons, that sometimes occur in young children. Of the remaining children, 64 completed the cardiopulmonary exercise test successfully while reaching their full exercise capacity.

Ranges of cardiovascular performance parameters are presented for a homogenous group of 24 TOF, 20 TGA, and 20 TCPC patients with no significant differences in baseline parameters like age, body weight, and systemic ventricular pump function. Only the echocardiographic parameters of tissue doppler, TAPSE and RV-Strain showed significant differences between the groups. All patients were Caucasian. Patient characteristics are shown in Table 1.

Data from the cardiopulmonary exercise testing of children with Tetralogy of Fallot are presented in Table 2. There was a significant difference between girls and boys in O2 pulse (p = 0.033), HR at VT1 (p = 0.002) and \(\dot_\) at VT2 (p = 0.021).

Data from the cardiopulmonary exercise testing of children with Transposition of Great Arteries are presented in Table 3. \(\dot_\) at VT1 (p = 0.018) as well as OUES (l/min) (p < 0.01) and \(\dot_\) at VT2 (p < 0.01) are significantly different between the two sexes.

Data from the cardiopulmonary exercise testing of children after TCPC are presented in Table 4. There were no significant differences between girls and boys for any of the measured variables.

TGA patients reached the highest \(V_peak\) values followed by patients with Tetralogy of Fallot and children with TCPC (Tables 2, 3, 4).

Data from TOF, TGA, and TCPC patients were compared and showed a significant difference in \(\dot_peak\) (p = 0.014) and oxygen uptake efficiency (p = 0.026). The relationship between \(\dot_peak\), OUES and age in each congenital heart disease group using linear regression analysis is shown in Figs. 1 and 2.

Correlation between Vo2 peak and age

Correlation between Vo2 peak and OUES

Overall, there were no significant correlations between the \(\dot_peak\) and age [TOF to \(\dot_peak\), (p = 0.728); TGA to \(\dot_peak\) (p = 0.351); TCPC to \(\dot_peak\) (p = 0.945)].

The following formulas were deduced to determine a typical range of \(\dot_peak\)/kg in children aged 4–8.

$$}\;\dotO_ peak\left( }} \mathord}} }*}} \right)}}} \right. \kern-0pt} }*}} \right)}}} \right) = 41.41 + }\left( }} \mathord}} }} \right. \kern-0pt} }} \right)*0.33$$

$$}\;\dotO_ peak\left( }} \mathord}} }*}} \right)}}} \right. \kern-0pt} }*}} \right)}}} \right) = 53.51}\left( }} \mathord}} }} \right. \kern-0pt} }} \right)*1.2$$

$$}\;\dotO_ peak\left( }} \mathord}} }*}} \right)}}} \right. \kern-0pt} }*}} \right)}}} \right) = 38.49 + }\left( }} \mathord}} }} \right. \kern-0pt} }} \right)*0.07$$

Results of the correlation between OUES/kg and age groups are shown in Fig. 2. OUES/kg values did not differ significantly between the congenital heart disease groups with increasing age [TOF to OUES/kg (p = 0.823) TGA to OUES/kg (p = 0.178); TCPC to OUES/kg (p = 0.710)].

The following formulas were deduced to determine average values of OUES/kg in children aged 4–8.

$$}}} \mathord}} }}}} \right. \kern-0pt} }}} = 0.045 = 0.04 + 3.61^ *}\left( }} \mathord}} }} \right. \kern-0pt} }} \right)$$

$$}}} \mathord}} }}}} \right. \kern-0pt} }}} = 0.051 = 0.07 - 2.03^ *}\left( }} \mathord}} }} \right. \kern-0pt} }} \right)$$

$$}}} \mathord}} }}}} \right. \kern-0pt} }}} = 0.043 = 0.05 - 4.69^ *}\left( }} \mathord}} }} \right. \kern-0pt} }} \right)$$

Data did not show a significant correlation between echocardiographic parameters and the oxygen uptake efficiency, LVEF, GLPS, RV-Strain, TAPSE, Trans-mitral E–A and \(V_peak\) values (LVEF: p = 0.354; GLPS: p = 0.232; RV-Strain: 0.985).