Oxygen uptake efficiency slope (OUES) and peak oxygen consumption (VO₂peak) are exercise parameters that can predict cardiac morbidity in patients with numerous heart diseases. But the predictive value in patients with tetralogy of Fallot is still undetermined, especially in children. We evaluated the prognostic value of OUES and VO₂peak in children with total repair of tetralogy of Fallot. Retrospective cohort study. Forty tetralogy of Fallot patients younger than 12 years old were recruited. They underwent a cardiopulmonary exercise test during the follow-up period after total repair surgery. The results of the cardiopulmonary exercise test were used to predict the cardiac related hospitalization in the following two years after the test. OUES normalized by body surface area (OUES/BSA) and the percentage of predicted VO₂peak appeared to be predictive for two-year cardiac related hospitalization. Receiver operating characteristic curve analysis demonstrated that the best threshold value for OUES/BSA was 1.029 (area under the curve = 0.70, p = 0.03), and for VO₂peak was 74% of age prediction (area under the curve = 0.72, p = 0.02). The aforementioned findings were confirmed by Kaplan–Meier plots and log-rank test. OUES/BSA and VO₂peak are useful predictors of cardiac-related hospitalization in children with total repair of tetralogy of Fallot.

Coronary artery (CA) abnormalities influence exercise capacity (EC) of patients with Kawasaki disease (KD), and Z-score of CA is a well established method for detecting CA aneurysm. We studied the influence of KD on cardiopulmonary function and EC; meanwhile we analyzed echocardiographic findings of KD patients. We also assessed the correlation between CA Z-score and EC of KD patients to see if CA Z-score of KD patients could reflect EC during exercise. Sixty-three KD patients were recruited as KD group 1 from children (aged 5–18 y) who received transthoracic echocardiographic examinations and symptom-limited treadmill exercise test for regular follow-up of KD from January 2010 to October 2014 in 1 medical center. We then divided KD group 1 into KD group 2 (<5 y, n = 12) and KD group 3 (≥5 y, n = 51) according to time interval between KD onset to when patients received test. Control groups were matched by age, sex, and body mass index. Max-Z of CA was defined as the maximal Z-score of the proximal LCA or RCA by Dalliarre equation or Fuse calculator. All routine parameters measured during standard exercise test were similar between KD and control groups, except that peak rate pressure products (PRPPs) in KD group 1 to 3 were all lower than corresponding control groups significantly (P = 0.010, 0.020, and 0.049, respectively). PRPPs correlated with Max-Z of CA by both equations modest inversely (by Dallaire, P = 0.017, Spearman rho = −0.301; by Fuse, P = 0.014, Spearman rho = −0.309). Our study recruited larger number of KD patients and provided a newer data of EC of KD patients. Our finding suggests that after acute stage of KD, patients could maintain normal cardiorespiratory fitness. Therefore, we believe that it is important to promote cardiovascular health to KD patients and KD patients should exercise as normal peers. However, since KD patients might still have compromised coronary perfusion during exercise, it remains crucial to assess and monitor cardiovascular risk of KD patients. Max-Z of CA correlates with PRPP modest inversely and might be used as a follow-up indicator of CA reserve during exercise after acute stage of KD.

Peak metabolic equivalent (MET) is the most reliable indicator of cardiorespiratory fitness (CRF). The aim of this study was to examine the association between CRF indicated by peak MET and body mass index (BMI) or fat mass index (FMI) in Taiwanese children and adolescents (C-A). Data of 638 C-A aged 10–18 that received symptom-limited treadmill exercise testing was analyzed. Anthropometry-body composition was measured by vector bioelectrical impedance analysis. BMI was defined as body weight (kg)/body height (m)² and FMI was defined as fat mass (kg)/body height (m)². BMI was grouped by Taiwanese obesity cut-off points. FMI Class-I was categorized by percentage of body fat. FMI Class-II used the reference values from Korean C-A. Excess adiposity was defined as (1) “overweight” and “obesity” by BMI, (2) greater than the sex- and age-specific 75th percentile of whole subjects by FMI Class-I, and (3) greater than 95th percentiles of reference value by FMI Class-II. Boys had significantly higher fat mass and FMI, and had more excess adiposity than girls (all p < 0.05). Both boys and girls with excess adiposity (by any definition) had lower MET at anaerobic threshold (AT MET) and peak MET (all p < 0.001). BMI and FMI were significantly negatively associated with both AT MET and peak MET significantly (all p < 0.001). FMI (95% CI: −0.411~−0.548) correlated with peak MET more than BMI (95% CI: −0.134~ −0.372) did. Excess adiposity affected CRF negatively. It is concluded that weight management should start early in childhood.

A predischarge submaximal exercise test is often recommended after acute myocardial infarction (AMI) as part of phase I cardiac rehabilitation. In this study, a submaximal exercise parameter, oxygen uptake efficiency slope (OUES), was used to monitor the benefit of early mobilization within 48 h after AMI. An early mobilization protocol within 48 h after AMI has been initiated since 1 September 2012 in our center. Patients with onset time of AMI within 1 year before and 1 year after initiation of the early mobilization protocol were recruited for comparisons. Sixty patients were analyzed on the basis of this criterion, and were subjected to predischarge submaximal exercise tests. The OUES calculated with 100% exercise duration (OUES100) and calculated with the first 50% of exercise duration (OUES50) were obtained and analyzed. Both OUES100 and OUES50 of the AMI patients with early mobilization were significantly higher than those without early mobilization (P=0.025 and 0.007, respectively). The OUES100 and OUES50 were also highly correlated (r=0.891, P<0.001). The subgroup analysis using patients within 3 months before and 3 months after initiation of the protocol also showed a significant difference. OUES could be used to measure the exercise capacity and monitor the effect of phase I cardiac rehabilitation in patients soon after AMI. Early mobilization within 48 h following AMI significantly enhanced the patient’s exercise capacity.