Lucas G. Van Der Hauwaert

Exercise testing after correction of tetralogy of Fallot: the fallacy of a reduced heart rate response.

Thirty-nine patients, 5 to 19 years of age, were studied 1 to 10.5 years (mean 4.5) after surgical correction of tetralogy of Fallot (TF). In 32 of them the results of an exercise performance test based on heart rate response to submaximal exercise (VO2, 170 [bpm]) was compared with another index of physical performance capacity, which is independent from heart rate: the ventilatory threshold. In patients operated for TF, the mean heart rate during exercise was significantly lower than that corresponding to the same level of exercise in normal children (p less than 0.001) and their mean VO2, 170 was normal. Theoretically, these findings could be interpreted as indicating a normal or high physical performance capacity. By contrast, the ventilatory threshold was significantly lower than that in normal children: it averaged 89.3 +/- 15.7%, 79.7 +/- 14.4%, and 88.5 +/- 15.8% of the mean value in normal children matched for age, weight, and height, respectively. More patients had a subnormal value for ventilatory threshold than for VO2, 170: 58% had a ventilatory threshold below the 95% confidence limits for age-matched normal individuals and 75% had a subnormal value when compared to weight-matched normal children. For VO2, 170, these values were 39% and 34%, respectively (p less than 0.05). We recommend the evaluation of the exercise performance capacity in patients operated for TF not only by measuring heart rate response and VO2, 170 which may be misleading because of relative bradycardia, but also by analyzing gas exchange and determining the ventilatory threshold.

Cardiorespiratory exercise capacity after surgical closure of atrial septal defect is influenced by the age at surgery.

To study the influence of age at the time of the operation on long-term functional performance in children undergoing surgery for atrial septal defect (ASD) of the secundum type, exercise tolerance was assessed in 24 patients and values were compared with those of normal subjects. Patients were divided into two groups: 11 patients had surgery before the age of 5 years (group 1) and 13 patients had surgery at a later age (group 2). There were no significant differences between groups 1 and 2 with regard to the pulmonary-to-systemic flow ratio, pulmonary artery pressure, and the interval between surgery and exercise testing. Performance capacity was assessed by determination of the ventilatory threshold during submaximal exercise. The mean value for the ventilatory threshold in group 1 was normal (99.4 +/- 15.1% of the age-predicted normal value). In the children who were more than 5 years of age at the time of the operation, the ventilatory threshold was below normal (84.5 +/- 10.9% of the age-predicted normal value). Furthermore, in group 2 more patients (77%) had values that were below normal (below the 95% confidence limit of the age-predicted normal value) compared with group 1 (27%). It is concluded that functional performance capacity is better when surgical closure of ASD is performed in early childhood and before the age of 5 years rather than at a later age.

Ventilatory anaerobic threshold for evaluating exercise performance in children with congenital left-to-right intracardiac shunt

SummaryThe ventilatory response to graded treadmill exercise was studied in 50 children with congenital heart disease (CHD), a left-to-right intracardiac shunt, and compared to that of age and sex-matched healthy children. In all these children, a breakpoint in the minute ventilation

Premature closure of the foramen ovale and congenital pulmonary cystic lymphangiectasis in aortic valve atresia or in severe aortic valve stenosis

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Long-term echocardiographic assessment of dilated cardiomyopathy in children

in relation to increasing oxygen uptake

Cardiac chamber growth pattern determined by two-dimensional echocardiography

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