The safety of early post-operative cardiac catheterisation has been described following congenital heart surgery. Optimal timing of early post-operative cardiac catheterisation remains uncertain. The aim of this study was to describe the safety of early post-operative cardiac catheterisation and its impact on cardiac ICU and hospital length of stay, duration of mechanical ventilation, and extracorporeal support.

This single-centre retrospective cohort study compared clinical and outcome variables between “early” early post-operative cardiac catheterisation (less than 72 hours after surgery) and “late” early post-operative cardiac catheterisation (greater than 72 hours after surgery) groups using Chi-squared, Student’s t, and log-rank test (or appropriate nonparametric test).

In total, 132 patients were included, 22 (16.7%) “early” early post-operative cardiac catheterisation, and 110 (83.3%) “late” early post-operative cardiac catheterisation. Interventions were performed in 63 patients (51.5%), 7 (11.1%) early and 56 (88.9%) late. Complications of catheterisation occurred in seven (5.3%) patients, two early and five late. There were no major complications. Patients in the late group trended towards a longer stay in the cardiac ICU (19 days [7, 62] versus 11.5 days [7.2, 31.5], p = 0.6) and in the hospital (26 days [9.2, 68] versus 19 days [13.2, 41.8], p = 0.8) compared to the earlier group.

“Early” early post-operative cardiac catheterisation was associated with an overall low rate of complications. Earlier catheterisations trended towards shorter cardiac ICU and hospital length of stays. Earlier catheterisations may lead to earlier recovery for patients not following an expected post-operative course.

Many patients with Fontan physiology are unable to achieve the minimum criteria for peak effort during cardiopulmonary exercise testing. The purpose of this study is to determine the influence of physical activity and other clinical predictors related to achieving peak exercise criteria, signified by respiratory exchange ratio ≥ 1.1 in youth with Fontan physiology.

Secondary analysis of a cross-sectional study of 8–18-year-olds with single ventricle post-Fontan palliation who underwent cardiopulmonary exercise testing (James cycle protocol) and completed a past-year physical activity survey. Bivariate associations were assessed by Wilcoxon rank-sum test and simple regression. Conditional inference forest algorithm was used to classify participants achieving respiratory exchange ratio > 1.1 and to predict peak respiratory exchange ratio.

Of the n = 43 participants, 65% were male, mean age was 14.0 ± 2.4 years, and 67.4% (n = 29) achieved respiratory exchange ratio ≥ 1.1. Despite some cardiopulmonary exercise stress test variables achieving statistical significance in bivariate associations with participants achieving respiratory exchange ratio > 1.1, the classification accuracy had area under the precision recall curve of 0.55. All variables together explained 21.4% of the variance in respiratory exchange ratio, with peak oxygen pulse being the most informative.

Demographic, physical activity, and cardiopulmonary exercise test measures could not classify meeting peak exercise criteria (respiratory exchange ratio ≥ 1.1) at a satisfactory accuracy. Correlations between respiratory exchange ratio and oxygen pulse suggest the augmentation of stroke volume with exercise may affect the Fontan patient’s ability to sustain high-intensity exercise.