Slopes of oxygen uptake versus exercise intensity, carbon dioxide output versus oxygen uptake, and ventilation versus carbon dioxide together with anaerobic threshold in patients with congenital heart disease and normal controls
| SlopeV˙o 2 v exercise intensity (ml/min2/kg) | Ventilatory anaerobic threshold (ml/min/kg) | Ventilatory anaerobic threshold (% normal) | SlopeV˙co 2 vV˙o 2 | SlopeV˙e v V˙co 2 | |
| Normal controls (n=24) | 2.42 (0.68) | 29.0 (3.1) | – | 1.05 (0.13) | 30.3 (8.5) |
| TF (n=30) | 1.68 (0.75)1-150 | 24.9 (3.6)1-150 | 85.1 (10.6)1-150 | 1.20 (0.18)1-150 | 41.5 (13.7)1-150 |
| TGA (n=29) | 1.50 (0.64)1-150 | 22.6 (4.7)1-150 | 78.0 (13.3)1-150 | 1.26 (0.20)1-150 | 47.0 (15.4)1-150 |
Data are means (SD).
↵1-150 p < 0.005, normal controls v patients (TF and TGA).
Slope V˙co 2 vV˙o 2, slope of carbon dioxide outputv oxygen uptake from oxygen uptake at ventilatory anaerobic threshold until oxygen uptake at heart rate of 170 beats/min; slope V˙e vV˙co 2, slope of ventilationv carbon dioxide output during graded exercise; TF, tetralogy of Fallot after repair; TGA, transposition of the great arteries after atrial switch operation;V˙co 2, carbon dioxide output;V˙o 2, oxygen uptake. Ventilatory anaerobic threshold (% of normal) is expressed as a percentage of the mean value obtained in normal children and adolescents of same age and sex.