Impairments and developmental delay are often reported in infants and young children with CHD. However, currently, there is no data regarding cognitive abilities assessed by standardised intelligence tests in adults with CHD. This study assesses the cognitive function in Fontan patients compared with acyanotic CHD patients whether restrictions in cognitive function are present in adulthood and its association with health-related quality of life.

Forty-four adult CHD (female n = 21 (47.7%); mean age 34.7 ± 11.9 years), 22 with Fontan circulation and 22 with acyanotic CHD, underwent the Wechsler Intelligence Scale for adults as patients during routine follow-up in 2018. The Medical Outcomes Study Questionnaire Short-Form 36 Health Survey (SF-36) assessed health-related quality of life.

Fontan patients showed significantly better results in the FSIQ (p = 0.020) and perceptual reasoning (p = 0.017) in comparison with patients with acyanotic CHD. All adult CHD patients showed normal IQ in subscales and full-scale IQ (FSIQ). In health-related quality of life, no association with cognitive function was found and no significant difference between both CHD groups, but trends to reduced values in acyanotic adult CHD.

Interestingly, our study results in adult Fontan patients showed that it is possible to live an adult life with normal cognitive function and good health-related quality of life with a univentricular heart. Thus, this study could be a guidepost for more in-depth studies on cognitive function in Fontan survivors. In addition, the focus should be on health-related quality of life of adult CHD with simple CHD in particular, since a reduced health-related quality of life is not only medically based.

To evaluate heart rate against workload and oxygen consumption during exercise in Fontan patients.

Fontan patients (n = 27) and healthy controls (n = 25) underwent cardiopulmonary exercise testing with linear increase of load. Heart rate and oxygen uptake were measured during tests. Heart rate recovery was recorded for 10 minutes.

Heart rate at midpoint (140 ± 14 versus 153 ± 11, p < 0.001) and at maximal effort (171 ± 14 versus 191 ± 10 beats per minute, p < 0.001) of test was lower for patients than controls. Heart rate recovery was similar between groups. Heart rate in relation to workload was higher for patients than controls both at midpoint and maximal effort. Heart rate in relation to oxygen uptake was similar between groups throughout test. Oxygen pulse, an indirect surrogate measure of stroke volume, was reduced at maximal effort in patients compared to controls (6.6 ± 1.1 versus 7.5 ± 1.4 ml·beat−1·m−2, p < 0.05) and increased significantly less from midpoint to maximal effort for patients than controls (p < 0.05).

Heart rate is increased in relation to workload in Fontan patients compared with controls. At higher loads, Fontan patients seem to have reduced heart rate and smaller increase in oxygen pulse, which may be explained by inability to further increase stroke volume and cardiac output. Reduced ability to increase or maintain stroke volume at higher heart rates may be an important limiting factor for maximal cardiac output, oxygen uptake, and physical performance.