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.

Chest pain is a common complaint among paediatric patients and cardiac troponin (cTn) level is often part of the initial emergency department evaluation. It is well known that after intense endurance exercise cTn levels can be elevated in patients with otherwise healthy hearts, however the effect shorter duration exercise has on cTn levels in this population is not known.

Determine the behaviour of cTn levels in healthy children and adolescent patients after short burst, high-intensity aerobic exercise.

Patients without haemodynamically significant heart disease referred for a treadmill exercise stress test (EST) were recruited over a 6-month period. cTn levels were measured prior to exercise and 4 hours after exercise.

Thirteen patients enrolled. Indications for EST were exertional syncope (six), chest pain (four), and long QT syndrome (three). The median exercise time was 12.9 (9.9–13.7) minutes with an average endurance at the fiftieth percentile for age and maximum heart rate rose to an average of 92 (74–98)% of the predicted peak for age. cTn levels prior to exercise were undetectable in all patients. There was no cTn rise in any patient after exercise. There were no ischaemic changes or arrhythmias on exercise electrocardiograms.

Serum cTn levels do not rise significantly in healthy children after short duration, high-intensity aerobic exercise. Physicians evaluating paediatric patients with an elevated cTn level after less than prolonged strenuous activity likely cannot attribute this lab value solely to exercise and may need to undertake further cardiac investigation.

Numerous patients are assessed in the emergency department (ED) for chest pain suggestive of acute coronary syndrome (ACS) and subsequently discharged if found to be at low risk. Exercise stress testing is frequently advised as a follow-up investigation for low-risk patients; however, compliance with such recommendations is poorly understood. We sought to determine if compliance with follow-up for exercise stress testing is higher in patients for whom the investigation is ordered at the time of ED discharge, compared with patients who are advised to arrange testing through their family physician (FP).

Low-risk chest pain patients being discharged from the ED for outpatient exercise stress test and FP follow-up were randomized into 2 groups. ED staff ordered an exercise stress test for the intervention group, and the control group was advised to contact their FP to arrange testing. The primary outcome was completion of an exercise stress test at 30 days, confirmed through both patient contact and stress test results. Patients were unaware that our primary interest was their compliance with the exercise stress testing recommendations.

Two-hundred and thirty-one patients were enrolled and baseline characteristics were similar between the 2 groups. Completion of an exercise stress test at 30 days occurred in 87 out of 120 (72.5%) patients in the intervention group and 60 out of 107 (56.1%) patients in the control group. The difference in compliance rates (16.4%) between the 2 groups was statistically significant (χ2 = 6.69, p < 0.001) with a relative risk of 1.29 (95% confidence interval 1.18–1.40), and the results remained significant after a “worst case” sensitivity analysis involving 4 control group cases lost to follow-up. When subjects were contacted by telephone 30 days after the ED visit, 60% of those who were noncompliant patients felt they did not have a heart problem and that further testing was unnecessary.

When ED staff order an outpatient exercise stress test following investigation for potential ACS, patients are more likely to complete the test if it is booked for them before ED discharge. After discharge, many low-risk chest pain patients feel they are not at risk and do not return to their FP for further testing in a timely manner as advised. Changing to a strategy of ED booking of exercise stress testing may help earlier identification of patients with coronary heart disease.