Objective: To investigate the postoperative cardiopulmonary fitness of children with congenital heart diseases (CHD). Methods: This is a retrospective study. A total of 136 children after cardiac correction undergoing cardiopulmonary exercise test (CPET) in Shanghai Children's Medical Center from March 1 to June 30, 2021 were selected. According to the surgical procedure, the children were divided into two groups: the biventricular correction group (BV group) (n=75) and single ventricular correction group (SV group) (n=61). The BV group was divided into two subgroups: simple congenital heart disease (S-CHD) group (n=35) and complex congenital heart disease (C-CHD) group (n=40). CPET parameters, including VO₂ max, VO₂/kg max, VO₂/kg@AT, O₂/HR max, HRR, PetCO₂ max, CI, HRR at 1 min, VE/VCO₂ slope, OUES/kg and EOV, were analyzed. CPET parameters of patients underwent different procedure were compared. In the subgroup analysis, CPET parameters of patients in S-CHD group and C-CHD group were compared. The parameters of the BV group were compared with the normal value. Linear correlation analysis was used to identify the correlation between the CPET parameters. Results: A total of 136 children with CHD after surgery were enrolled. The age was (9.4±3.1) (ranged 6.2-16.0) years, and there was 84 (61.8%) male. All the children completed CPET examination safely without experiencing serious circulation abnormalities. Compared with the SV group, the VO₂/kg max ((32.6±6.9) ml·kg^-1·min^-1 vs. (23.5±5.9) ml·kg^-1·min^-1, P<0.001), O₂/HR max ((7.24±2.93) ml/beat vs. (6.35±2.17)ml/beat, P=0.030), HRR at 1 min ((32.5±13.9) beat/min vs. (26.3±12.5) beat/min, P=0.036), OUES/kg (36.9±8.8 vs. 29.7±11.8, P=0.001) were significantly higher, VE/VCO₂ slope (29.1±5.20 vs. 35.1±8.0, P<0.001) and incidence of EOV (32.0%(24/75) vs. 57.4%(31/61), P=0.027) were significantly lower in BV group. Compared with the simple CHD subgroup, VE/VCO₂ slope and the incidence of EOV were higher, VO₂/kg max, O₂/HR max, HRR at 1 min and OUES/kg were lower in the complex CHD subgroup (all P<0.05). Cardiopulmonary function parameters of the BV group were lower than the normal value. Linear correlation analysis showed that VO₂/kg@AT was strongly correlated with VO₂/kg max (r=0.86, P<0.001), VO₂/kg max was strongly correlated with OUES/kg (r=0.63, P<0.001), HRR was strongly correlated with CI (r=0.91, P<0.001), and VO₂/kg max was strongly correlated with OUES/kg (r=0.63, P<0.001). VE/VCO₂ slope was strongly correlated with PetCO₂ max (r=1.00, P<0.001). Conclusions: The exercise cardiopulmonary function of children after single ventricular correction is weaker than that of biventricular correction, and the exercise tolerance of children after biventricular correction is lower than that of normal children. Among the children after biventricular correction, the exercise tolerance of children with complex CHD is lower than that of children with simple CHD. Postoperative CPET is of important realistic significance for CHD children.
Adolescent ; Child ; China ; Exercise Test/methods* ; Female ; Heart Defects, Congenital/surgery* ; Humans ; Male ; Oxygen Consumption ; Retrospective Studies

Objective To examine if the variations at sea level would be able to predict subsequent susceptibility to acute altitude sickness in subjects upon a rapid ascent to high altitude. Methods One hundred and six Han nationality male individuals were recruited to this research. Dynamic electrocardiogram, treadmill exercise test, echocardiography, routine blood examination and biochemical analysis were performed when subjects at sea level and entering the plateau respectively. Then multiple regression analysis was performed to construct a multiple linear regression equation using the Lake Louise Score as dependent variable to predict the risk factors at sea level related to acute mountain sickness (AMS). Results Approximately 49.05% of the individuals developed AMS. The tricuspid annular plane systolic excursion (22.0±2.66 vs. 23.2±3.19 mm, t=1.998, P=0.048) was significantly lower in the AMS group at sea level, while count of eosinophil [(0.264±0.393)×10⁹/L vs. (0.126±0.084)×10⁹/L, t=-2.040, P=0.045], percentage of differences exceeding 50 ms between adjacent normal number of intervals (PNN50, 9.66%±5.40% vs. 6.98%±5.66%, t=-2.229, P=0.028) and heart rate variability triangle index (57.1±16.1 vs. 50.6±12.7, t=-2.271, P=0.025) were significantly higher. After acute exposure to high altitude, C-reactive protein (0.098±0.103 vs. 0.062±0.045 g/L, t=-2.132, P=0.037), aspartate aminotransferase (19.7±6.72 vs. 17.3±3.95 U/L, t=-2.231, P=0.028) and creatinine (85.1±12.9 vs. 77.7±11.2 mmol/L, t=-3.162, P=0.002) were significantly higher in the AMS group, while alkaline phosphatase (71.7±18.2 vs. 80.6±20.2 U/L, t=2.389, P=0.019), standard deviation of normal-to-normal RR intervals (126.5±35.9 vs. 143.3±36.4 ms, t=2.320, P=0.022), ejection time (276.9±50.8 vs. 313.8±48.9 ms, t=3.641, P=0.001) and heart rate variability triangle index (37.1±12.9 vs. 41.9±11.1, t=2.020, P=0.047) were significantly lower. Using the Lake Louise Score as the dependent variable, prediction equation were established to estimate AMS: Lake Louise Score=3.783+0.281×eosinophil-0.219×alkaline phosphatase+0.032×PNN50. Conclusions We elucidated the differences of physiological variables as well as noninvasive cardiovascular indicators for subjects after high altitude exposure compared with those at sea level. We also created an acute high altitude reaction early warning equation based on the physiological variables and noninvasive cardiovascular indicators at sea level.
Acute Disease ; Adolescent ; Adult ; Alkaline Phosphatase/blood* ; Altitude ; Altitude Sickness/physiopathology* ; Aspartate Aminotransferases/blood* ; Blood Pressure/physiology* ; C-Reactive Protein/analysis* ; Creatinine/blood* ; Electrocardiography/methods* ; Exercise Test/methods* ; Heart Rate/physiology* ; Humans ; Leukocyte Count ; Male ; Risk Factors ; Young Adult

PURPOSE: Remote ischemic preconditioning (RIPC), induced by repeated bouts of ischemia followed by reperfusion of the arm or leg is a noninvasive strategy to protect a target organ against oxidative stress and injury caused by ischemia and reperfusion. Interestingly, recent evidence suggests that RIPC may also improve exercise performance by increasing maximal oxygen consumption, but such finding remain equivocal. As such, the purpose of the study was to examine the effect of RIPC on exercise performance in healthy individuals. METHODS: In a randomized cross-over design, 17 healthy male participants (age, 23±3 years) were exposed to either a sham control (six cycles of 5 minutes bilateral thigh cuff occlusion at 20 mm Hg) or RIPC (six cycles of 5 minutes bilateral thigh cuff occlusion at 180 mm Hg) an hour before a maximal exercise test. We measured maximal oxygen consumption, power output, heat rate, blood pressure, and blood lactate as exercise performance parameters during a maximal exercise test performed on an upright bicycle. RESULTS: Compared with the sham control, RIPC improved maximal oxygen consumption (7.4%, p=0.025) and maximal power output (11.5%, p=0.010), whereas other exercise performance parameters remained unchanged with RIPC (p>0.05). CONCLUSION: Taken together, the improvements in maximal oxygen consumption and maximal power output induced by RIPC may suggest that RIPC should be considered as a method for improving exercise performance.
Arm ; Blood Circulation ; Blood Pressure ; Cross-Over Studies ; Exercise Test ; Exercise Tolerance* ; Hot Temperature ; Humans ; Ischemia ; Ischemic Preconditioning* ; Lactic Acid ; Leg ; Male ; Methods ; Oxidative Stress ; Oxygen Consumption ; Reperfusion ; Thigh ; Young Adult*

Despite the importance of cardiorespiratory fitness, no practical method exists to estimate maximal oxygen consumption (VO₂max) without a specific exercise protocol. We developed an estimation model of VO₂max, using maximal activity energy expenditure (aEEmax) as a new feature to represent the level of physical activity. Electrocardiogram (ECG) and acceleration data were recorded for 4 days in 24 healthy young men, and reference VO₂max levels were measured using the maximal exercise test. aEE was calculated using the measured acceleration data and body weight, while heart rate (HR) was extracted from the ECG signal. aEEmax was obtained using linear regression, with aEE and HR as input parameters. The VO₂max was estimated from the aEEmax using multiple linear regression modeling in the training group (n = 16) and was verified in the test group (n = 8). High correlations between the estimated VO₂max and the measured VO₂max were identified in both groups, with a 15-hour recording being sufficient to produce a highly accurate VO₂max estimate. Additional recording time did not significantly improve the accuracy of the estimation. Our VO₂max estimation method provides a robust alternative to traditional approaches while only requiring minimal data acquisition time in daily life.
Acceleration ; Body Weight ; Electrocardiography ; Energy Metabolism ; Exercise Test ; Heart Rate ; Humans ; Linear Models ; Male ; Methods ; Motor Activity ; Oxygen Consumption

OBJECTIVE: To explore the feasibility of cardiopulmonary exercise test (CPET) in leukemia patients after chemotherapy. METHODS: Leukemia patients with histologically confirmed hematologic malignancies were reviewed. We evaluated for CPET, between receiving chemotherapy and undergoing stem cell transplantation after 2 weeks. We recorded exercise testing and physiologic parameters during CPET between January 2013 to May 2015. All patients were subjected to symptoms limited to exercise testing, according to the Modified Bruce Protocol. We considered that if respiratory exchange ratio achieved was over 1.10, participants had successfully completed CPET. We dichotomized all participants into two groups (normal group, normal range of resting heart rate; higher group, over 100 per minute of heart rate). RESULTS: 30 patients were finally enrolled. All participants had no adverse effects during the exercise test. Mean peak double product was 26,998.60 mmHg·beats/min (range, 15,481–41,004), and mean peak oxygen consumption (VO₂ peak) was 22.52±4.56 mL/kg/min. Significant differences were observed in the normal group with VO₂ peak (mean, 24.21 mL/kg/min; p=0.027) and number of prior intensive chemotherapy, compared to the higher group (mean, 1.95; p=0.006). CONCLUSION: Our results indicate that CPET in leukemia patients before stem cell transplantation was very safe, and is an efficient method to screen for patients with poor cardiac functions. As CPET presents the parameters which reveal the cardiopulmonary functions, including VO₂ peak, double product and exercise capacity, this exercise test would help to predict the physical performance or general condition of the leukemia patients.
Drug Therapy* ; Exercise Test* ; Feasibility Studies* ; Heart ; Heart Rate ; Hematologic Neoplasms ; Humans ; Leukemia* ; Methods ; Oxygen Consumption ; Reference Values ; Rehabilitation ; Stem Cell Transplantation ; Tachycardia

BACKGROUNDDual sensor (DS) for rate adaption was supposed to be more physiological. To evaluate its superiority, the DS (accelerometer [ACC] and minute ventilation [MV]) and normal sinus rate response were compared in a self-controlled way during exercise treadmill testing.

METHODSThis self-controlled study was performed in atrioventricular block patients with normal sinus function who met the indications of pacemaker implant. Twenty-one patients came to the 1-month follow-up visit. Patients performed a treadmill test 1-month post implant while programmed in DDDR and sensor passive mode. For these patients, sensor response factors were left at default settings (ACC = 8, MV = 3) and sensor indicated rates (SIRs) for DS, ACC and MV sensor were retrieved from the pacemaker memories, along with measured sinus node (SN) rates from the beginning to 1-minute after the end of the treadmill test, and compared among study groups. Repeated measures analysis of variance and profile analysis, as well as variance analysis of randomized block designs, were used for statistical analysis.

RESULTSFifteen patients (15/21) were determined to be chronotropically competent. The mean differences between DS SIRs and intrinsic sinus rates during treadmill testing were smaller than those for ACC and MV sensor (mean difference between SIR and SN rate: ACC vs. SN, MV vs. SN, DS vs. SN, respectively, 34.84, 17.60, 16.15 beats/min), though no sensors could mimic sinus rates under the default settings for sensor response factor (ACC vs. SN P-adjusted < 0.001; MV vs. SN P-adjusted = 0.002; DS vs. SN P-adjusted = 0.005). However, both in the range of 1 st minute and first 3 minutes of exercise, only the DS SIR profile did not differ from sinus rates (P-adjusted = 0.09, 0.90, respectively).

CONCLUSIONSThe DS under default settings provides more physiological rate response during physical activity than the corresponding single sensors (ACC or MV sensor). Further study is needed to determine if individual optimization would further improve adaptive performance of the DS.

Adult ; Aged ; Cardiac Pacing, Artificial ; methods ; Exercise ; physiology ; Exercise Test ; Female ; Humans ; Male ; Middle Aged ; Pacemaker, Artificial

BACKGROUNDThe long-time exercise test (ET) is used to diagnose the primary periodic paralyses (PPs). However the reference values of ET are many and various. This study aimed to investigate the reference value of long-time ET in the diagnosis of PPs.

METHODSWe recruited 108 healthy subjects, 68 patients with PPs, and 72 patients with other diseases for the study. The procedure of ET was made on the basis of the McManis' method. Electrical responses were recorded from right abductor digiti minimi (ADM) muscle when stimulation of the ulnar nerve at the wrist. After the compound muscle action potential (CMAP) was monitored, subjects were then asked to contract the muscle as strongly as possible for 5 minutes. CMAPs were recorded for 2 seconds immediately after cessation of exercise, then every 5 minutes for 10 minutes, and finally every 10 minutes for 50 minutes. In general, the CMAP amplitudes will fall below the pre-exercise levels in an hour. The largest decrease was calculated and used as results of ET.

RESULTSThe CMAP amplitude decreases had no significant differences between groups when the healthy adults were grouped according to age, gender, height, weight and test time. Decreases in PPs patients (57.76%) were significantly more than in healthy subjects (15.21%) and other disease patients (18.10%, P < 0.001). Receiver operating characteristic (ROC) curve analysis showed that the best threshold is 35.50%.

CONCLUSIONSIn the long-time exercise test, threshold of 35.50% for the CMAP amplitude decrease was identified for abnormal. The result is not influenced by age, gender, height, weight, and test time. About 7.4% of healthy subjects were abnormal in ET.

Adult ; Aged ; Aged, 80 and over ; Exercise Test ; methods ; Female ; Humans ; Male ; Middle Aged ; Paralyses, Familial Periodic ; diagnosis ; Prospective Studies ; Reference Values

INTRODUCTIONCardiorespiratory fitness (CRF) is an independent predictor of voluminous health outcomes and can be measured using non-exercise fitness assessment (NEFA) equations. However, the accuracy of such equations in Asian populations is unknown. The objective of this study was to cross-validate the NEFA equation, developed by Jurca et al in 2005, in the adult Singaporean population.

METHODSA total of 100 participants (57 men, 43 women; aged 18-65 years) were recruited, and their maximal oxygen consumption (VO2 max) was measured in the laboratory by indirect calorimetry. The participants also completed the NEFA questionnaire, which helps to predict VO2 max with the NEFA equation. The relationship between NEFA-predicted and laboratory-measured VO2 max values was analysed.

RESULTSOverall, our study demonstrated a high correlation between the NEFA-predicted and laboratory-measured VO2 max values (r = 0.83). The Pearson's correlation coefficient values for the men and women in the study were 0.61 and 0.77, respectively. To improve the accuracy of the predictive equation, we transformed the original equation developed by Jurca et al into new equations that would allow estimation of VO2 max with and without resting heart rate as a variable.

CONCLUSIONThe modified NEFA equations accurately estimated CRF and may be applied to the majority of adult Singaporeans. With this, health practitioners and researchers are now able to assess CRF levels at both the individual and population levels in either the primary care, fitness or research setting.

Adolescent ; Adult ; Aged ; Exercise Test ; methods ; Female ; Health Status ; Humans ; Male ; Middle Aged ; Models, Statistical ; Oxygen Consumption ; physiology ; Physical Fitness ; physiology ; Predictive Value of Tests ; Reproducibility of Results ; Singapore ; Surveys and Questionnaires ; Young Adult

BACKGROUNDThere is no research, either at home or abroad, focusing on assessing the cardiopulmonary functional reserve and exercise tolerance in patients with pulmonary embolism (PE), but the benefits of early exercise are well recognized. The goals of this study were to assess cardiopulmonary functional reserve in treated PE patients using the inert gas rebreathing method of the cardiopulmonary exercise test (CPET), and to compare it with traditional methods.

METHODSCPET on the bicycle ergometer were performed in 40 patients with age, gender, body mass index, systolic blood pressure, and pulmonary function matched. The first group was the PE group composed of 16 PE patients (5 male, 11 female) who were given the standard antithrombotic therapy for two weeks. The second group was composed of 24 normal individuals (10 male, 14 female). Both groups were evaluated by cardiac ultrasound examination, 6-minute walking test (6MWT), and CPET.

RESULTS(1) Right ventricular systolic pressure (RVSP) in the PE group increased significantly compared to the control group, (34.81 ± 8.15) mmHg to (19.75 ± 3.47) mmHg (P < 0.01). But neither right atrial end-systolic diameter (RASD) nor right ventricular end-diastolic diameter (RVDD) in the PE patients had changed when compared with the controls. The 6-minute walk distance was significantly reduced in the PE patients compared with normal subjects, (447.81 ± 79.20) m vs. (513.75 ± 31.45) m (P < 0.01). Both anaerobic threshold oxygen consumption (VO(2)AT) and peak oxygen consumption (VO(2)peak) were significantly lower in patients with PE, while CO(2) equivalent ventilation (VE/VCO(2) slope) was higher; VO(2)AT (9.44 ± 3.82) ml×kg(-1)×min(-1) vs. (14.62 ± 2.93) ml×kg(-1)×min(-1) (P < 0.01) and VO2peak (12.26 ± 4.06) ml×kg(-1)×min(-1) vs. (23.46 ± 6.15) ml×kg(-1)×min(-1) (P < 0.01) and VE/VCO(2) slope 35.47 ± 6.66 vs. 26.94 ± 3.16 (P < 0.01). There was no significant difference in resting cardiac output (CO) between the PE and normal groups, whereas peak cardiac output (peak CO) and the difference between exercise and resting cardiac output (ΔCO) were both significantly reduced in the PE group; peak CO (5.97 ± 2.25) L/min to (8.50 ± 3.13) L/min (P < 0.01), ΔCO (1.29 ± 1.59) L/min to (3.97 ± 2.02) L/min (P < 0.01). (2) The 6-minute walk distance did not correlated with CPET except for the VO2 peak in patients with PE, r = 0.675 (P < 0.01).

CONCLUSIONSThe cardiopulmonary functional reserve was reduced in patients with PE. CPET is an accurate, quantitative evaluation of cardiopulmonary functional reserve for PE patients.

Aged ; Exercise Test ; methods ; Exercise Tolerance ; physiology ; Female ; Humans ; Male ; Middle Aged ; Oxygen Consumption ; physiology ; Pulmonary Embolism ; physiopathology ; therapy

OBJECTIVE: To determine whether there was agreement between the short daytime ApneaGraph (dAG) and nocturnal ApneaGraph (nAG) in diagnosing sleep respiratory events initially and identifying the site of obstruction in airway. METHOD: Twenty four patients diagnosed OSAHS by PSG were enrolled. The apnea-hypopnea index (AHI), apnea index (AI), obstructive apnea-hypopnea index (OAHI), central apnea hypopnea index (CAHI), mixed apnea index (MAHI), lowest oxygen saturation (LSaO2) and the proportion of upper/lower obstruction (UPPER, LOWER) of patients were measured using both dAG and nAG. RESULT: There were no significant differences between nAG and dAG for the following parameters: AHI, AI, CAHI, MAHI, OAHI, the proportion of upper/lower obstruction, or LSaO2 (P>0.05). There were significant positive correlations between nAG and dAG with regard to AHI, AI, MAHI, OAHI, the proportion of upper/lower obstruction , LSaO2 except CAHI. CONCLUSION The dAG has similar results with nAG in early diagnosis of sleep respiratory events and identifying the level of airway obstruction. The time-saving dAG is of considerable referential importance in diagnosis of sleep respiratory events and analysing the level of airway obstruction.
Adult ; Airway Obstruction ; Exercise Test ; methods ; Female ; Humans ; Male ; Middle Aged ; Polysomnography ; methods ; Sleep ; Sleep Apnea, Obstructive ; diagnosis ; physiopathology