Dyspnoea in Cyanotic Congenital Heart Disease

Fontan Fenestration Closure Has No Acute Effect on Exercise Capacity but Improves Ventilatory Response to Exercise

“…The effect of fenestration closure on the Fontan patient's ventilatory abnormalities also deserves further consideration. It has been recognized previously that patients with right-to-left shunts exhibit an abnormal ventilatory response to exercise (26,27). The physiologic mechanisms underlying this response have been illuminated by simultaneous expiratory gas and arterial blood gas analysis (28), which again emphasizes the importance of and distinction between relative pulmonary and systemic blood flow and the central mechanisms that underlie respiratory control and gas exchange in this patient population.…”

Oxygen Consumption During Recovery From Exercise in Children With Congenital Heart Disease

“…This is not surprising, since other studies have shown that patients with leftto-right shunts have an excessive ventilatory response to exercise that is not directly related to the level of pulmonary artery pressure or to the magnitude of pulmonary flow. 5 Gold et al1" observed, in a study of children with tetralogy of Fallot and systemic-to-pulmonary artery shunt, that there was an excessive ventila¬ tory response during exercise with an increased ventilatory equivalent for C02 and abnormally increased wasted ventilation, defined as the ratio of the physiological dead space to the tidal volume. In our group D patients, both the YE/YC02 ratio and the VE/Y02 ratio were elevated, suggesting a similar decrease in efficiency of venti¬ lation.…”

ATP, CP, and Lactate Concentrations in Muscle Tissue during Exercise in Male Patients with Tetralogy of Fallot

“…A low physical working capacity in T O F has been reported earlier (8, 9,12). The four subjects in Group I displayed a reduction in their maximal oxygen uptake to values 30-40 per cent of reported normal values for this age group (1, 2).…”

“…A lower than normal blood lactate concen- tration a t maximal exercise has been reported by others in TOF (9,22) and has formed the basis for the statement that these patients stopped working for reasons other than muscular ones, or that no hypoxia incapacitated the muscle (21). From the results of the present study, however, it is obvious that blood lactate concentration does not fully reflect the anaerobic metabolism.…”

“…This could be anticipated to result in an enhanced delivery of anaerobic energy. However, available information on blood lactate concentration during intensive exercise has shown that it is not especially high (9,22). This may suggest that adaptive changes in the circulatory and/or metabolic response t o exercise are brought into play.…”