A meta-analysis of cardiopulmonary exercise testing in pre-pubertal healthy children produces new information / Metanálise de testes de exercícios cardiopulmonares em crianças pré-púberes saudáveis

The objective of the paper was to analyze cardiopulmonary data and functional capacity in healthy children who have undergone ergospirometry. A systematic meta-analysis review of ergospirometry in children was performed based on reports indexed in PubMed, Bireme, and Embase. End points were age, sex, body mass index, maturation evaluation, the type of ergometer used for ergospirometry, and cardiopulmonary related values (peak heart rate and peak oxygen consumption [VO2]). Twenty articles were selected, which included 3,808 children, averaging 9.1years of age. A treadmill was used in 55% of the trials, and a cycle ergometer in the other 45% studies included in this analysis. The following statistically significant results were found: on subgroup analysis, peak VO2 values in boys on the treadmill was 20% higher than peak VO2 values in girls on the cycle ergometer; peak VO2 values in boys on the treadmill were 18% greater than that for girls on the same ergometer. BMI was inversely correlated with peak VO2 in the total analysis, and in female subjects on cycle ergometers. Peak heart rate during the ergospirometrical test was 5.6 BPM higher than the estimated 95% maximum heart rate. Most of the ergospirometrical parameters had not been reported in the original trials analyzed here. We conclude that peak VO2 value for pre-pubertal children are circa 18% higher in boys vs. girls and overall higher in treadmill vs. cycle ergometers.

O objetivo do trabalho foi analisar dados relativos à função cardiopulmonar e capacidade funcional em crianças saudáveis submetidas a ergoespirometria. Uma revisão meta-analítica sistemática de ergoespirometria em crianças foi realizada com base na literatura indexada no PubMed, Bireme, e Embase. Os parâmetros pesquisados foram: idade, sexo, índice de massa corporal, avaliação da maturação, tipo de ergômetro utilizado para ergoespirometria, e os valores cardiopulmonares relacionados (frequência cardíaca máxima e consumo máximo de oxigênio [VO2]). Vinte artigos foram selecionados, que incluíram 3808 crianças, com uma média de 9,1 anos de idade. Esteiras erogmétricas foram utilizadas em 55% dos ensaios, e bicicletas erogmétricas em outros 45% incluídos nesta análise. Os seguintes resultados estatisticamente significantes foram encontradas: em análise de subgrupo, valores de VO2 de pico em meninos, obtidos na esteira foram 20% maiores do que os respectivos valores em meninas na bicicleta ergométrica valores de VO2 pico em meninos na esteira foram 18% maiores do que para meninas no mesmo ergômetro. O Índice de massa corpórea correlacionou-se inversamente com VO2 de pico na análise total e em meninas testadas em ciclo-ergômetro. A frequência cardíaca máxima durante o teste ergo-espirométrico foi 5,6 BPM superior aos 95% da freqüência cardíaca máxima prevista. A maior parte dos parâmetros ergo-espirométricos não havia sido relatada nos estudos originais por nós analisados. A conclusão desta metanálise é que o valor de VO2 de pico para crianças pré-púberes é cerca de 18% maior nos meninos versus meninas e em esteira vs. ciclo-ergômetro.

Effects of age on aerobic capacity in heart failure patients under beta-blocker therapy: possible impact in clinical decision-making?

BACKGROUND: Heart failure (HF) is associated with impaired maximal aerobic capacity as indicated by decreases in peak oxygen uptake (peak VO(2)). Considering that aging by itself has a negative effect on this variable, the evaluation of maximum capacity is often questioned because current predicted peak VO(2) is based on subjects without heart disease or b-blocker therapy. In contrast, if decline in predicted and attained peak VO(2) were age-related, proportionally, loss of aerobic function (predicted peak VO(2), %) would remain stable over time in these patients. The purpose of this investigation is to assess the effects of age on peak VO(2) in HF patients taking b-blockers. METHODS: We retrospectively evaluated 483 (132 female) patients (aged 20-88 years, LVEF 31 ± 11%) with non-ischemic (n = 362), ischemic (n = 74) and Chagas-related HF (n = 47) who had been submitted to an incremental cardiopulmonary exercise testing on a motorized treadmill. Linear regression was used to develop the equation to predict peak VO(2), based on age. RESULTS: Peak VO(2) decreased 0.9 mL/min/kg per age-decade, maximum HR also decreased with aging and VE/VCO(2) slope was similar among all decades. The predicted new b-blocker equation to peak VO(2 bb) was 20.934 - 0.092 × age. CONCLUSIONS: Clinical interpretation of aerobic capacity impairment is influenced by aging in HF patients. This evidence must be considered when using peak VO(2) for prognostic stratification and clinical decision-making in patients with HF under b-blocker therapy.

Exercise capacity in early and late adult heart transplant recipients.

BACKGROUND: The aim of this study was to compare peak oxygen consumption (VO(2)), heart rate (HR) reserve and HR recovery in early and late heart transplant recipients. Moreover, we also aimed to correlate peak VO(2) and HR reserve. METHODS: Fivteen heart transplant recipients (8 early and 7 late), 8 ± 3 and 161 ± 58 months after transplantation, respectively, performed a cardiopulmonary exercise test. RESULTS: Early heart transplant recipients showed lower HR reserve compared to late heart transplant recipients, 39 ± 15 vs. 58 ± 19 bpm (p = 0.049), respectively. Peak VO(2) (23.4 ± 4 vs. 21.8 ± 5 mL/kg/min, p = 0.56), VO(2) respiratory compensation point (18.7 ± 2 vs. 18.5 ± 4 mL/ /kg/min, p = 0.48) and time of exercise testing (14 ± 3 vs. 13 ± 3 min, p = 0.95) %age- -predicted peakVO(2) (65 ± 12 vs. 70 ± 10%, p = 0.24) were not different between the groups. Moreover, peak VO2 and %age-predicted peakVO(2) correlated with HR reserve only in early heart transplant recipients (r = 0.89, p = 0.003 and r = 0.71, p = 0.04, respectively). Early heart transplant recipients increased HR (2.5 ± 2.0% at fi rst minute and 0.7 ± 2.3% at the second minute), while late recipients decreased HR (-6.0 ± 4.7 at fi rst minute and -15.5 ± 2.4 at the second minute) at the recovery period of cardiopulmonary exercise test. CONCLUSIONS: Exercise capacity did not show difference between early and late heart transplant recipients. HR reserve was higher in late compared to early recipients. HR reserve only correlated with peak VO(2) in early recipients. Moreover, only late heart transplant recipients showed decrease in HR during the recovery period of cardiopulmonary exercise test.

Age-related maximum heart rate among ischemic and nonischemic heart failure patients receiving ß-blockade therapy.

BACKGROUND: Equations to predict maximum heart rate (HR(max)) in heart failure (HF) patients receiving ß-adrenergic blocking (BB) agents do not consider the cause of HF. We determined equations to predict HR(max) in patients with ischemic and nonischemic HF receiving BB therapy. METHODS AND RESULTS: Using treadmill cardiopulmonary exercise testing, we studied HF patients receiving BB therapy being considered for transplantation from 1999 to 2010. Exclusions were pacemaker and/or implantable defibrillator, left ventricle ejection fraction (LVEF) >50%, peak respiratory exchange ratio (RER) <1.00, and Chagas disease. We used linear regression equations to predict HR(max) based on age in ischemic and nonischemic patients. We analyzed 278 patients, aged 47 ± 10 years, with ischemic (n = 75) and nonischemic (n = 203) HF. LVEF was 30.8 ± 9.4% and 28.6 ± 8.2% (P = .04), peak VO(2) 16.9 ± 4.7 and 16.9 ± 5.2 mL kg(-1) min(-1) (P = NS), and the HR(max) 130.8 ± 23.3 and 125.3 ± 25.3 beats/min (P = .051) in ischemic and nonischemic patients, respectively. We devised the equation HR(max) = 168 - 0.76 × age (R(2) = 0.095; P = .007) for ischemic HF patients, but there was no significant relationship between age and HR(max) in nonischemic HF patients (R(2) = 0.006; P = NS). CONCLUSIONS: Our study suggests that equations to estimate HR(max) should consider the cause of HF.