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After a Fontan repair for congenital heart disease, 42 patients underwent graded supine bicycle exercise tests at levels relevant to normal daily activities. Results were compared with those of 28 age-matched normal control subjects. At rest, the cardiac index, stroke index and systolic blood pressure were comparable in both groups, but increases with exercise were smaller in the patients with a Fontan circulation. The heart rate at rest was higher in the Fontan group, but this difference disappeared as soon as exercise started. To determine whether there are limitations intrinsic to the Fontan circulation at these levels of exercise, the 10 best performers were compared with 10 age-matched control subjects; no differences were found in cardiac index, stroke index, heart rate or blood pressure at any exercise level. Analysis of the determinants of cardiac output showed that at the other end of the spectrum poor performance after a Fontan operation did not result from inadequate levels of heart rate, but from an inability to increase or maintain stroke volume. Multivariate analysis demonstrated that impairment of ventricular contractility, only when severe, predicted limited performance. There was no evidence of increased afterload, particularly in the poor performers. Therefore, ventricular filling, which is determined primarily by the pulmonary vascular bed, appears to be a major determinant of functional result after a Fontan repair.

Development of heart block in children of SSA/SSB-autoantibody-positive women is associated with maternal age and displays a season-of-birth pattern, 2012, Annals of the Rheumatic Diseases, (71) Methods. The influence of fetal gender, maternal age, parity and time of birth on heart block development was analyzed in 145 families including Ro/La-positive (n= 190) and Ro/Lanegative (n=165) pregnancies.Results. We observed a recurrence rate of 12.1% in Ro/La-positive women, and no recurrence in Ro/La-negative women. Fetal gender and parity did not influence the development of heart block in either group. Maternal age in Ro/La-positive pregnancies with a child affected by heart block was however significantly higher than in pregnancies resulting in babies without heart block (p<0.01). Further, seasonal timing of pregnancy influenced the outcome. Gestational susceptibility-weeks 18-24 occurring during January-March correlated with a higher proportion of heart block pregnancies and lower vitamin D levels, and a corresponding higher proportion of children with heart block born in the summer (p<0.02). Maternal age or seasonal timing of pregnancy did not affect the outcome in Ro/La-negative pregnancies.Conclusion. This study identifies maternal age and seasonal timing of pregnancy as novel risk factors for congenital heart block development in Ro/La positive pregnancy. These observations indicate that the risk can be modified, and will be important for counseling when a pregnancy is considered. 4Congenital complete heart block without cardiac malformation is a rare disease, affecting 1 in 15,000 to 20,000 births in the general population. An association with the presence of maternal autoantibodies to Ro/SSA and/or La/SSB is however well established [1,2], and the risk of complete congenital heart block is 1-2% in Ro/SSA-positive pregnancies [3][4][5][6]. Furthermore, the reported risk of giving birth to a second child with complete heart block for anti-Ro/SSA positive mothers ranges from 12 to 20% [7][8][9], despite the persistence of the maternal autoantibodies [10].This indicates that additional factors are critical for establishing the heart block. Fetal genetic susceptibility has been suggested as a potential risk factor [11,12], and polymorphisms in the gene encoding TGFβ have been implicated in the development of heart block [13,14]. Variations in the intrauterine environment between pregnancies have also been suggested to contribute to the penetrance of the disease. Maternal disease severity has been investigated as such a potential risk factor, but was not found to contribute to the development of congenital heart block [15].Given the rarity of congenital heart block occurrence in the general population, it is difficult to investigate potential risk factors associated with the disease. In particular, very little information is available on the influence of maternal age and parity on pregnancy outcome in anti-Ro/La positive mothers. In an effort to address these questions in a reasonable cohort we identified heart ...