Software development to standardize the clinical diagnosis of exercise oscillatory ventilation in heart failure.

BACKGROUND: Exercise oscillatory ventilation (EOV) is characterized by periodic oscillations of minute ventilation during cardiopulmonary exercise testing (CPET). Despite its prognostic value in chronic heart failure (HF), its diagnosis is complex due to technical limitations. An easier and more accurate way of EOV identification can contribute to a better approach and clinical diagnosis. This study aims to describe a software development to standardize the EOV diagnosis from CPET's raw data in heart failure patients and test its reliability (intra- and inter-rater). METHODS: The software was developed in the "drag-and-drop" G-language using LabVIEW®. Five EOV definitions (Ben-Dov, Corrà, Kremser, Leite, and Sun definitions), two alternative approaches, one smoothing technique, and some basic statistics were incorporated into the interface to visualize four charts of the ventilatory response. EOV identification was based on a set of criteria verified from the interaction between amplitude, cycle length, and oscillation time. Two raters analyzed the datasets. In addition, repeated measurements were verified after six months using about 25% of the initial data. Cohen's kappa coefficient (κ) was used to investigate the reliability. RESULTS: Overall, 391 tests were analyzed in duplicate (inter-rater reliability) and 100 tests were randomized for new analysis (intra-rater reliability). High inter-rater (κ > 0.80) and intra-rater (κ > 0.80) reliability of the five EOV diagnoses were observed. CONCLUSION: The present study proposes novel semi-automated software to detect EOV in HF, with high inter and intra-rater agreements. The software project and its tutorial are freely available for download.

Frailty influences the vascular responsiveness of elderly individuals with chronic heart failure.

INTRODUCTION: Frailty is highly prevalent in heart failure (HF) patients. HF is associated with oxidative stress and chronic inflammation, which impair oxygen use by skeletal muscles. Little is known about the influence of frailty on vascular responsiveness and tissue oxygenation. OBJECTIVE: Analyze the influence of frailty on vascular responsiveness and muscle oxygenation in elderly individuals with and without HF. METHODS: Individuals aged ≥60 years, with or without HF, were evaluated for frailty (phenotype). Near-infrared spectroscopy (NIRS) was used to assess muscle oxygenation at rest (oxygen saturation - StO2 and deoxyhemoglobin) and during handgrip exercise (minimum StO2 and maximum deoxyhemoglobin), and oxygenation variables. STATISTICAL ANALYSIS: Results were grouped according to the frailty phenotype: non-frail, pre-frail, and frail. Shapiro-Wilk test was used to assess normality. Data were compared using a two-way analysis of variance (ANOVA). Bonferroni post hoc test was applied to determine the influence of frailty or HF on NIRS variables. SPSS software was used in the analyses; p < 0.05 was considered significant. RESULTS: 55 elderly participants (61.8% female; 70.4 ± 7.2 years old; 28 HF patients) participated in the study. 32.7% (n = 18) were classified as non-frail, 43.3% (n = 24) as pre-frail, and 23.6% (n = 13) as frail. The analysis of vascular responsiveness (n = 52) identified an influence (p < 0.05) of frailty on the reperfusion rate (slope 2 and ∆StO2 of nadir-peak) and desaturation during occlusion (area under the curve of StO2) in HF patients. There was no influence of frailty or HF on muscle oxygenation at rest and during exercise (n = 54; p > 0.05). CONCLUSION: The coexistence of frailty and HF seems to impair vascular responsiveness, as frail elderly participants with HF presented lower reperfusion rates and higher desaturation levels during the arterial occlusion test. However, the presence of frailty or HF alone had no influence on muscle oxygenation at rest or during exercise.

Functional capacity in a rat model of heart failure: impact of myocardial infarct size.

NEW FINDINGS: What is the central question of this study? To the best of our knowledge, no studies have evaluated oxygen uptake, carbon dioxide production and exercise tolerance in rats that have undergone myocardial infarction classified by myocardial infarct (MI) size. What is the main finding and its importance? Oxygen uptake and exercise intolerance are MI size dependent, and classification based on MI size can distinguish rats with functional capacity impairment. Rats with a large MI (>40% of the left ventricle) might provide a good model for the testing of new therapies that have the potential to modify the variables of functional capacity. Oxygen uptake (V̇O2) and exercise tolerance in rats classified by myocardial infarct (MI) size are underexplored. The aim of this study was to evaluate V̇O2, carbon dioxide production (V̇CO2) and exercise tolerance in rats that had undergone myocardial infarction. Fourteen weeks after myocardial infarction or sham surgery, rats underwent an integrated approach to evaluation of left ventricular function and V̇O2/V̇O2V̇CO2V̇CO2, exercise tolerance and skeletal muscle weight. Based on determination of MI size, rats were assigned to sham-operated controls (Sham, n = 12), small myocardial infarction (SMI, n = 8) and large myocardial infarction (LMI, n = 5) groups. The LMI rats showed lower systolic (ejection fraction and fractional shortening) and diastolic (E/A ratio) left ventricular function compared with SMI. Maximal V̇O2 (∼24%, P < 0.05), V̇O2 reserve (∼30%, P < 0.05), time to exhaustion (∼36%, P < 0.05) and maximal velocity (∼30%, P < 0.05) were lower in LMI compared with sham-operated control animals, with no difference between SMI rats and sham-operated controls. Maximal V̇CO2 and respiratory exchange ratio showed no significant difference between MI rats and sham-operated control rats. The LMI rats demonstrated lower gastrocnemius weight (∼12%, P < 0.05) and soleus weight (∼19%, P = 0.07) compared with sham-operated control rats. Significant correlations between MI size, left ventricular end-diastolic pressure, right ventricle hypertrophy, pulmonary congestion, ejection fraction and fractional shortening with maximal V̇O2 and distance run were observed. Oxygen uptake and exercise intolerance are MI size dependent.

Maximal oxygen uptake and exercise tolerance are improved in rats with heart failure subjected to low-level laser therapy associated with resistance training.

Exercise tolerance and maximal oxygen uptake (VO2max) are reduced in heart failure (HF). The influence of combined resistance training (RT) and low-level laser therapy (LLLT) on exercise tolerance and VO2max in HF has not yet been explored. The aim of this study was to evaluate the influence of combined RT and LLLT on VO2max and exercise tolerance in rats with HF induced by myocardial infarction (MI). Rats were allocated to sedentary sham (Sed-Sham, n = 12), sedentary heart failure (Sed-HF, n = 9), RT heart failure (RT-HF, n = 7) and RT associated with LLLT heart failure (RT + LLLT-HF, n = 7) groups. After MI or sham surgery, rats underwent a RT and LLLT protocol (applied immediately after RT) for 8 weeks. VO2max and exercise tolerance were evaluated at the end of protocol. HF rats subjected to LLLT combined with RT showed higher VO2basal (41 %), VO2max (40 %), VO2reserve (39 %), run distance (46 %), time to exhaustion (30 %) and maximal velocity (22 %) compared with HF rats that underwent RT alone. LLLT associated with RT improved oxygen uptake and exercise tolerance compared with RT alone in HF rats.

Light-emitting diode therapy (LEDT) improves functional capacity in rats with heart failure.

The syndrome of heart failure (HF) promotes central and peripheral dysfunctions that result in functional capacity decrease, leading to fatigue, dyspnea, and exercise intolerance. The use of light-emitting diode therapy (LEDT) has shown good results reducing fatigue and exercise intolerance, when applied on skeletal muscles before or after exercises. Thereby, the aim of this study was to compare the effects of LEDT on functional capacity, aerobic power, and hemodynamic function in HF rats. Male Wistar rats (230-260 g) were randomly allocated into three experimental groups: Sham (n = 6), Control-HF (n = 4), and LEDT-HF (n = 6). The animals were subjected to an exercise performance test (ET) with gas analysis coupled in a metabolic chamber for rats performed two times (6 and 14 weeks after myocardial infarction). On the day after the baseline aerobic capacity test, the animals were submitted during 8 weeks to the phototherapy protocol, five times/week, 60 s of irradiation, 6 J delivered per muscle group. Statistical analysis was performed by one- and two-way ANOVAs with repeated measures and Student-Newman-Keuls post hoc tests (p ≤ 0.05). Comparing the percentage difference (Δ) between baseline and the final ET, there was no significant difference for the VO2max variable considering all groups. However, Sham and LEDT-HF groups showed higher relative values than the Control-HF group, respectively, for distance covered (27.7 and 32.5 %), time of exercise test (17.7 and 20.5 %), and speed (13.6 and 12.2 %). In conclusion, LEDT was able to increase the functional capacity evaluated by distance covered, time, and speed of exercise in rats with HF.

The influence of low-level laser therapy on parameters of oxidative stress and DNA damage on muscle and plasma in rats with heart failure.

In heart failure (HF), there is an imbalance between the production of reactive oxygen species and the synthesis of antioxidant enzymes, causing damage to the cardiovascular function and increased susceptibility to DNA damage. The aim of this study was to evaluate the influence of low-level laser therapy (LLLT) on parameters of oxidative stress and DNA damage in skeletal muscle and plasma of rats with HF. Wistar rats were allocated into six groups: "placebo" HF rats (P-HF, n = 9), "placebo" Sham rats (P-sham, n = 8), HF rats at a dose 3 J/cm(2) of LLLT (3 J/cm(2)-HF, n = 8), sham rats at a dose 3 J/cm(2) of LLLT (3 J/cm(2)-sham, n = 8), HF rats at a dose 21 J/cm(2) of LLLT (21 J/cm(2)-HF, n = 8) and sham rats at a dose 21 J/cm(2) of LLLT (21 J/cm(2)-sham, n = 8). Animals were submitted to a LLLT protocol for 10 days at the right gastrocnemius muscle. Comparison between groups showed a significant reduction in superoxide dismutase (SOD) activity in the 3 J/cm(2)-HF group (p = 0.03) and the 21 J/cm(2)-HF group (p = 0.01) compared to the P-HF group. 2',7'-Dihydrodichlorofluorescein (DCFH) oxidation levels showed a decrease when comparing 3 J/cm(2)-sham to P-sham (p = 0.02). The DNA damage index had a significant increase either in 21 J/cm(2)-HF or 21 J/cm(2)-sham in comparison to P-HF (p = 0.004) and P-sham (p = 0.001) and to 3 J/cm(2)-HF (p = 0.007) and 3 J/cm(2)-sham (p = 0.037), respectively. Based on this, laser therapy appears to reduce SOD activity and DCFH oxidation levels, changing the oxidative balance in the skeletal muscle of HF rats. Otherwise, high doses of LLLT seem to increase DNA damage.

Preliminary Effects of a Structured Educational Program in Cardiac Patients at Different Stages of Enrollment in Cardiovascular Rehabilitation.

This quasi-experimental study investigated the preliminary effects of a structured education intervention in a pooled sample of cardiovascular rehabilitation (CR) patients in Brazil. Recently enrolled (RE) and long-term enrolled (LTE) patients attended 12 weekly education sessions in addition to three weekly exercise sessions. Patients completed surveys assessing disease-related knowledge, physical activity, food intake, self-efficacy, and health literacy. Functional capacity was assessed by the 6-minutes walking test. All outcomes were assessed at pre-,post-CR, and 6-months follow-up. Bonferroni correction was applied. In total, 69 (69.7%) patients completed all three assessments. There were significant improvements in knowledge pre-to post-test in both subgroups (p < 0.001), and in functional capacity (p ≤ 0.001) and food intake (p ≤ 0.001) pre-to post-test in the RE subgroup. Post-test knowledge was correlated to physical activity, functional capacity and health literacy. This preliminary study suggests the importance of structured education for CR patients. A larger study using a randomized controlled design is needed to determine efficacy.

Aerobic Exercise Prescription in Cardiac Rehabilitation Based on Heart Rate from Talk Test Stages and 6-Minute Walk Test. / Prescrição de Exercício Aeróbio na Reabilitação Cardíaca Baseada na Frequência Cardíaca dos Estágios do Teste da Fala e do Teste de Caminhada de 6 Minutos.

BACKGROUND: Although the Talk Test (TT) is a reliable and low-cost test, its use for aerobic exercise prescription is still limited. OBJECTIVE: To analyze the heart rate (HR) in the stages of the TT and at the peak of the 6-minute walk test (6MWT) as a parameter to prescribe aerobic exercise compared with HR at the first and second ventilatory thresholds (VT1 and VT2) of cardiopulmonary exercise test (CPET). METHODS: Individuals with cardiovascular disease attended three assessment days: 1) anamnesis and CPET; 2) 6MWT; and 3) TT. One-way repeated measures ANOVA or Friedman's test were used to compare HR at VT1 and VT2 with HR at TT stages: last positive (TT+), first equivocal (TT±), and negative (TT-), and at the peak of the 6MWT. Pearson's or Spearman's test assessed correlations between HR at VTs, TT stages, and 6MWT. Statistical significance was set at 5%. RESULTS: The study included 22 cardiac patients (13 men, 61 ± 8 years). HR at VT1 was similar to HR at TT+ (p = 0.987) and TT± (p = 0.154), and moderately correlated with TT+ (r = 0.479, p = 0.024). HR at VT2 was similar to TT- (p = 0.383), with a strong correlation (r = 0.757, p < 0.001). HR at the peak of the 6MWT was significantly different from HR at TT+, TT±, and VT1 (p = 0.001, p = 0.005, and p < 0.001, respectively) but similar to TT- (p = 0.68). CONCLUSIONS: HR at TT+ and TT- reflect HR at VT1 and VT2, respectively, differently from 6MWT, which was similar only to VT2. TT may be an objective test to assist aerobic exercise prescription in cardiac rehabilitation.

FUNDAMENTO: Embora o Teste da Fala (TF) seja um teste confiável e de baixo custo, seu uso para prescrição de exercício aeróbio ainda é limitado. OBJETIVO: Analisar a frequência cardíaca (FC) dos estágios do TF e no pico do teste de caminhada de 6 minutos (TC6min) como parâmetro para a prescrição de exercício aeróbio comparando com a FC no primeiro e segundo limiares ventilatórios (LV1 e LV2) do teste cardiopulmonar de exercício (TCPE). MÉTODOS: Pacientes com doença cardiovascular compareceram a 3 dias de avaliação: 1) anamnese e TCPE; 2) TC6min; e 3) TF. Foram usados ANOVA unidirecional de medidas repetidas ou teste de Friedman para comparar a FC no LV1 e LV2 com a FC nos estágios do TF: último positivo (TF+), primeiro equívoco (TF±) e negativo (TF−) e no pico do TC6min. O teste de Pearson ou Spearman avaliou se há correlação entre FC em LVs, estágios do TF e TC6min. A significância estatística foi fixada em 5%. RESULTADOS: O estudo incluiu 22 pacientes cardíacos (13 homens, 61 ± 8 anos). A FC no LV1 foi semelhante à FC no TF+ (p = 0,987) e TF± (p = 0,154), e moderadamente correlacionada com o TF+ (r = 0,479, p = 0,024). A FC no LV2 foi semelhante ao TF− (p = 0,383), com forte correlação (r = 0,757, p < 0,001). A FC no pico do TC6min foi significativamente diferente da FC no TF+, TF± e LV1 (p = 0,001, p = 0,005 e p < 0,001, respectivamente), mas semelhante ao TF− (p = 0,68). CONCLUSÕES: A FC no TF+ e TF− reflete a FC no LV1 e LV2, respectivamente, diferentemente do TC6min, que foi semelhante apenas ao LV2. O TF pode ser um teste objetivo para auxiliar a prescrição de exercício aeróbio na reabilitação cardíaca.

Feasibility of a Virtual Educational Programme for Behaviour Change in Cardiac Patients from a Low-Resource Setting.

Patient education is an integral part of recovery from a critical cardiac life event and a core component of cardiac rehabilitation (CR) programmes. This study addressed the feasibility of a virtual educational programme for behaviour change in CR patients from a low-resource setting in Brazil. Cardiac patients from a CR programme closed due to the pandemic received a 12-week virtual educational intervention (WhatsApp messages and bi-weekly calls from healthcare providers). Acceptability, demand, implementation, practicality, and limited efficacy were tested. Overall, 34 patients and 8 healthcare providers agreed to participate. The intervention was considered practical and acceptable by the participants, who reported a satisfaction median of 9.0 (7.4-10.0)/10 (patients) and 9.8 (9.6-10.0)/10 (providers). The main difficulties in carrying out the intervention activities were related to technology, motivation to self-learning, and a lack of in-person orientation. All the patients reported that the information included in the intervention was aligned with their information needs. The intervention was associated with changes in exercise self-efficacy, sleep quality, depressive symptoms, and performance of high-intensity physical activity. In conclusion, the intervention was considered feasible to educate cardiac patients from a low-resource setting. It should be replicated and expanded to support patients that face barriers to onsite CR participation. Challenges related to technology and self-learning should be addressed.

Impact of COVID-19's on Cardiovascular Rehabilitation Programs in Brazil: An Online Survey-Based Cross-Sectional Study. / Impacto da COVID-19 nos Programas de Reabilitação Cardiovascular no Brasil: Um Estudo Transversal Baseado em uma Pesquisa Online.

BACKGROUND: The COVID-19 pandemic had an impact on cardiovascular rehabilitation (CR) programs in Brazil. OBJECTIVES: To describe the characteristics of CR programs in Brazil, the impacts of the first epidemiological wave of COVID-19 (first 60 days) on the programs and present the initiatives used to overcome the impacts. METHOD: This cross-sectional and retrospective study utilized a specific online survey. Participants were coordinators of CR programs. Variables were presented by Brazilian geographic region and as the following categories: demographic, clinical and operational characteristics. The significance level for statistical analysis was set at 5%. RESULTS: Fifty-nine CR programs were responsible for 5,349 patients, of which only 1,817 were post-acute cardiovascular events, which corresponded to 1.99% of hospitalized patients in the month prior to the survey (n=91,231). The greatest impact was the suspension of on-site activities, which occurred similarly in areas with the highest and the lowest rates of COVID-19 in the period. Forty-five programs (75%) were shortly interrupted, while three (5%) were ended. All 42 programs that already used remote rehabilitation strategies noticed a substantial increase in activities, based primarily on the use of media and video calling. Only three (5%) considered safe to see patients during the first 60 days. CONCLUSIONS: There was a reduction in the number of CR programs with the COVID-19 pandemic. Telerehabilitation activities increased during the first two months of the COVID-19 pandemic, but this was not enough to overcome the reduction in CR program activities across Brazil.

FUNDAMENTO: A pandemia da COVID-19 teve um impacto sobre os programas de reabilitação cardiovasculares (RC) no Brasil. OBJETIVOS: Descrever características dos programas de RC no Brasil, os impactos da primeira onda epidemiológica da COVID-19 (primeiros 60 dias) sobre os programas, e apresentar as iniciativas usadas para superar esses impactos. MÉTODOS: Este estudo transversal e retrospectivo usou um questionário online específico. Os participantes eram coordenadores de programas de RC. As variáveis foram apresentadas por região geográfica do Brasil, como as seguintes categorias: característica demográficas, clínicas e operacionais. O nível de significância estatística foi definido em 5%. RESULTADOS: Cinquenta e nove programas de RC atendiam 5349 pacientes, dos quais somente 1817 eram pacientes após eventos cardiovasculares agudos, o que correspondia a 1,99% dos pacientes internados no mês anterior à pesquisa (n=91.231). O maior impacto foi a suspensão das atividades presenciais, o que ocorreu de maneira similar em áreas com as taxas mais altas e áreas com as taxas mais baixas de COVID-19 no período. Quarenta e quatro (75%) programas foram interrompidos de forma breve, e três (5%) foram encerrados. Todos os 42 programas que já utilizavam estratégias de reabilitação remota notaram aumento substancial nas atividades, baseadas principalmente no uso da mídia e chamadas por vídeo. Somente três (5%) consideraram seguro atender pacientes durante os primeiros 60 dias. CONCLUSÕES: Houve redução no número de programas de RC devido a pandemia da COVID-19. Atividades de telerreabilitação aumentaram durante os primeiros dois meses da pandemia da COVID-19, mas que não foi suficiente para superar a redução nas atividades dos programas de RC no Brasil.

Linear and nonlinear analysis of heart rate variability in coronary disease.

OBJECTIVE: Coronary artery disease (CAD) and acute myocardial infarction (AMI) are associated with a reduction of heart rate variability (HRV). The aim of this study was to compare the HRV of CAD patients with and without AMI (CAD-AMI) with health-matched controls by linear (spectral analysis) and nonlinear [Shannon entropy (SE), conditional entropy (CE) and symbolic analysis (SA)] analysis. METHODS: Fifty-eight men were divided into three groups: healthy (n = 19, 57 ± 4 years), CAD (n = 20, 56 ± 10 years) and CAD-AMI (n = 19, 54 ± 12 years). The RR intervals were recorded at rest in the supine position for 10 min with an HR monitor (Polar(®)S810i). A series of 250 beats was selected to analyze variance, spectral analysis, SE, CE [complexity index (CI), normalized CI (NCI)] and SA (0V, 1V, 2LV and 2ULV patterns), as well as 0V (no significant variation) and 2ULV (two significant unlike variations), which reflect sympathetic and vagal modulation, respectively. One-way ANOVA (or the Kruskal-Wallis test when appropriate) and Pearson correlation were used. RESULTS: The CAD group had higher body mass index and weight than the CAD-AMI group, but no differences were found between the healthy and AMI groups. There were no differences between the groups regarding linear and nonlinear analysis. The 0V and 2ULV patterns were significantly correlated with the SE, CI and NCI of the three groups. INTERPRETATION: There was no difference between the groups regarding cardiac autonomic modulation by linear and nonlinear methods, which may be due to beta-blocker use, coronary angioplasty and the exercise capacity of healthy subjects.

Sensitivity and specificity of different exercise oscillatory ventilation definitions to predict 2-year major adverse cardiovascular outcomes in chronic heart failure patients.

BACKGROUND: Exercise oscillatory ventilation (EOV) shows a four-fold greater risk of adverse events. This study aims to analyze the sensitivity and specificity of three EOV diagnostic definitions to predict adverse outcomes at a 2-year follow-up and to compare its EOV prevalence and relations with the patient's profile. METHODS: Cardiopulmonary exercise tests from 233 heart failure patients were analyzed. Two blinded reviewers used a semiautomated software to identify EOV cases pattern according to the definitions of Ben-Dov, Corrà, and Leite. Data were grouped in EOV-positive or EOV-negative according to each definition. Baseline characteristics, EOV prevalence, relative risk, sensitivity, and specificity to predict 2-years of major adverse cardiovascular outcomes were analyzed. RESULTS: The Corrà definition led to the best prediction of 2-year major cardiovascular adverse outcomes (HR 2.46 [1.16 to 5.25]; p = 0.019, AUC = 0.618; p = 0.007). EOV prevalence was 17.2%, 17.2%, and 9.4% applying Ben-Dov, Corrà, and Leite definition, respectively. The main clinical differences between EOV-positive and EOV-negative patients were: MECKI score and VE/VCO2 slope (all definitions), and BNP levels (Ben-Dov and Leite). BNP levels were correlated with amplitude (rho = 0.255; p = 0.033) and cycle length (rho = 0.388; p = 0.002). CONCLUSION: Corrà definition was the only one that exhibited the capacity to predict major adverse cardiovascular outcomes at a 2-year follow-up. Regardless of its definition, EOV was more often prevalent in patients with a greater MECKI score and VE/VCO2 slope values.

Perceptions of Cardiac Rehabilitation Participants Regarding their Health Behaviors and Information Needs during the COVID-19 Pandemic in Brazil. / Percepções dos Participantes de Reabilitação Cardíaca sobre seus Comportamentos em Saúde e Necessidades de Informação durante a Pandemia COVID-19 no Brasil.

BACKGROUND: COVID-19 has impacted how people receive health care for many conditions, including cardiovascular diseases. OBJECTIVES: To examine perceptions of cardiac rehabilitation (CR) participants regarding their health behaviors and information needs during the COVID-19 pandemic in Brazil. METHODS: In this cross-sectional study, a 27-item questionnaire, developed by the investigators, was administered online to participants from two CR programs. Questions included health literacy (HL; using the Brief Health Literacy Screening Tool), technology use, perceptions before and during the COVID-19 pandemic, and information needs. Pearson correlation coefficients, paired t-tests, and ANOVA were used as appropriate. P < 0.05 was considered statistically significant for all tests. RESULTS: Overall, 159 (25.5%) CR participants answered the questionnaire. Of these, 89.9% had limited or marginal HL and 96.2% reported having internet access at home. Patients are mainly concerned about their family's health and their own, as well as how the coronavirus is dangerous to their health and how it has changed their lifestyle. Participants perceived that the quality of their health behaviors significantly decreased during the pandemic. The pandemic also changed information needs of CR participants as new needs emerged, such as the control of anxiety levels, staying motivated to live healthily during a pandemic, and how COVID-19 can impact their health condition. Participants with adequate HL significantly perceived the severity of the disease and having access to information significantly more than those with limited HL. CONCLUSIONS: Our results highlighted the impact of the pandemic on CR participants' perceptions regarding their health behaviors and information needs, which can be influenced by HL levels.

FUNDAMENTO: A COVID-19 afetou como as pessoas recebem atendimento de saúde para várias doenças, inclusive doenças cardiovasculares. OBJETIVOS: Examinar as percepções dos participantes de reabilitação cardíaca (RC) sobre seus comportamentos em saúde e necessidades de informação durante a pandemia da COVID-19 no Brasil. MÉTODOS: Neste estudo transversal, um questionário de 27 itens elaborado pelos investigadores foi administrado online a participantes de dois programas de RC. As perguntas incluíam letramento em saúde (LS; usando a Brief Health Literacy Screening Tool - Breve ferramenta de triagem de letramento em saúde), uso de tecnologia, percepções antes e durante a pandemia da COVID-19, e necessidades de informações. Foram usados coeficiente de correlação de Pearson, testes t pareados e ANOVA, conforme apropriado. Um p <0,05 foi considerado estatisticamente significativo para todos os testes. RESULTADOS: No total, 159 (25,5%) participantes de RC responderam ao questionário. Desses, 89,9% tinham LS limitado ou marginal, e 96,2% relataram ter acesso à internet de casa. Os pacientes se preocupam principalmente com a saúde de sua família e própria, além de como o coronavírus é perigoso para sua saúde e como mudou seu estilo de vida. Os participantes perceberam que a qualidade de seus comportamentos em saúde diminuiu significativamente durante a pandemia. A pandemia também mudou as necessidades de informações dos participantes de RC, já que novas necessidades surgiram, tais como, controle de níveis de ansiedade, manter a motivação para levar uma vida saudável durante a pandemia, e como a COVID-19 pode afetar sua condição de saúde. Participantes com LS adequado perceberam significativamente a gravidade da doença e tinham significativamente mais acesso a informações do que os pacientes com LS limitado. CONCLUSÕES: Nossos resultados destacaram o impacto da pandemia nas percepções dos participantes de RC em relação a seus comportamentos em saúde e necessidades de informação, que podem ser influenciados pelos níveis de LS.

Agreement between heart rate at first ventilatory threshold on treadmill and at 6-min walk test in coronary artery disease patients on ß-blockers treatment.

The purpose of this study was to verify the accuracy of the agreement between heart rate at the first ventilatory threshold (HRVT1) and heart rate at the end of the 6-min walk test (HR6MWT) in coronary artery disease (CAD) patients on ß-blockers treatment. This was a cross-sectional study with stable CAD patients, which performed a cardiopulmonary exercise test (CPET) on a treadmill and a 6-min walk test (6MWT) on nonconsecutive days. The accuracy of agreement between HRVT1 and HR6MWT was evaluated by Bland-Altman analysis and Lin's concordance correlation coefficient (rc), mean absolute percentage error (MAPE), and standard error of estimate (SEE). Seventeen stable CAD patients on ß-blockers treatment (male, 64.7%; age, 61±10 years) were included in data analysis. The Bland-Altman analysis revealed a negative bias of -0.41±6.4 bpm (95% limits of agreements, -13 to 12.2 bpm) between HRVT1 and HR6MWT. There was acceptable agreement between HRVT1 and HR6MWT (rc=0.84; 95% confidence interval, 0.63 to 0.93; study power analysis=0.79). The MAPE of the HR6MWT was 5.1% and SEE was 6.6 bpm. The ratio HRVT1/HRpeak and HR6MWT/HRpeak from CPET were not significantly different (81%±5% vs. 81%±6%, P=0.85); respectively. There was a high correlation between HRVT1 and HR6MWT (r=0.85, P<0.0001). Finally, the results of the present study demonstrate that there was an acceptable agreement between HRVT1 and HR6MWT in CAD patients on ß-blockers treatment and suggest that HR6MWT may be useful to prescribe and control aerobic exercise intensity in cardiac rehabilitation programs.

Expiratory Flow Limitation at Different Exercise Intensities in Coronary Artery Disease.

INTRODUCTION: Expiratory flow limitation (EFL) during moderate intensity exercise is present in patients with myocardial infarction (MI), whereas in healthy subjects it occurs only at a high intensity. However, it is unclear whether this limitation already manifests in those with stable coronary artery disease (CAD) (without MI). MATERIALS AND METHODS: Forty-one men aged 40-65 years were allocated into (1) recent MI (RMI) group (n = 8), (2) late MI (LMI) group (n = 12), (3) stable CAD group (n = 9), and (4) healthy control group (CG) (n = 12). All participants underwent two cardiopulmonary exercise tests at a constant workload (moderate and high intensity), and EFL was evaluated at the end of each exercise workload. RESULTS: During moderate intensity exercise, the RMI and LMI groups presented with a significantly higher number of participants with EFL compared to the CG (p < 0.05), while no significant difference was observed among groups at high intensity exercise (p > 0.05). Moreover, EFL was only present in MI groups during moderate intensity exercise, whereas at high intensity all groups presented EFL. Regarding the degree of EFL, the RMI and LMI groups showed significantly higher values at moderate intensity exercise in relation to the CG. At high intensity exercise, significantly higher values for the degree of EFL were observed only in the LMI group. CONCLUSION: The ventilatory limitation at moderate intensity exercise may be linked to the pulmonary consequences of the MI, even subjects with preserved cardiac and pulmonary function at rest, and not to CAD per se.

Inspiratory Muscle Training After Heart Valve Replacement Surgery Improves Inspiratory Muscle Strength, Lung Function, and Functional Capacity: A RANDOMIZED CONTROLLED TRIAL.

PURPOSE: The aim of this study was to analyze the effects of inspiratory muscle training (IMT) as a therapeutic strategy after heart valve replacement surgery (HVRS). METHODS: A double-blind, randomized, clinical trial that included patients undergoing elective HVRS, without post-operative complications, were allocated to 2 groups: IMT group (IMT-G) and IMT placebo group (IMT-PG). The IMT started 3 d after surgery and was performed twice daily for 4 wk. Lung function, maximum inspiratory pressure (MIP) as a measure of inspiratory muscle strength, functional capacity, and quality of life were assessed pre-operatively and at the end of training. RESULTS: The IMT-G recovered pre-operative MIP and lung function values after 4 wk of training. This group also increased the distance walked during the 6-min walk test (6MWD). In the IMT-PG, the values of MIP were below those found pre-operatively, with impairment of lung function and lower 6MWD in the final evaluation. At the end of IMT, MIP was correlated with the 6MWD and with the spirometry variables. CONCLUSIONS: IMT performed for 4 wk after HVRS was effective in restoring the values of inspiratory muscle strength and lung function to the pre-operative level and increasing the functional capacity assessed by the 6MWD. Furthermore, an association between lung function and functional capacity was observed, demonstrating the clinical relevance of the use of IMT in the rehabilitation process of these patients.

Regarding: "Inspiratory muscle training improves performance of a repeated sprints ability test in professional soccer players".

The Journal of Bodywork & Movement Therapies recently published an article by Silva et al., entitled "Inspiratory muscle training improves performance of a repeated sprints ability test in professional soccer players" (Silva et al., 2019). After close reading we find that the new findings of Silva et al., (2019) are relevant and provide a promising indication that IMT can improve the performance of young male soccer players. However, some additional important points must be considered when interpreting these positive findings.

The effects of inspiratory muscle training with linear workload devices on the sports performance and cardiopulmonary function of athletes: A systematic review and meta-analysis.

Inspiratory muscle training (IMT) is considered an ergogenic resource to improve sports performance. The aim of this systematic review is to evaluate the effects of IMT with linear workload devices (IMT-linear) on the sports performance and cardiopulmonary function of athletes. A search was conducted on several databases until July 2018. Eligible studies were independently reviewed by two reviewers. Methodological quality and quality of evidence were assessed with PEDro' score and GRADE, respectively. Statistical analysis was performed using the Review Manager 5.3 software. Twenty-five studies were selected for analysis. A total of 207 athletes were allocated to the IMT group, 143 athletes to the IMT-Sham, and 86 healthy individuals to the control group. The quality of studies was high (6 [3-8] points). IMT-linear improved maximal inspiratory pressure (MD -29.42 cmH2O [-35.65, -23.20]; p < 0.001), independent of sports modality. There was no influence of IMT on the maximal expiratory pressure and pulmonary function markers. It was observed that IMT-linear improves the sports performance (SMD 0.64 [0.35, 0.92]; p < 0.0001) with moderate effect size. The results suggest that IMT-linear represents an effective tool to improve the inspiratory muscle strength of athletes, as well as sports performance. However, IMT-linear did not shown effect on cardiopulmonary function.

Prescrição de Exercício Aeróbio na Reabilitação Cardíaca Baseada na Frequência Cardíaca dos Estágios do Teste da Fala e do Teste de Caminhada de 6 Minutos / Aerobic Exercise Prescription in Cardiac Rehabilitation Based on Heart Rate from Talk Test Stages and 6-Minute Walk Test

Resumo Fundamento Embora o Teste da Fala (TF) seja um teste confiável e de baixo custo, seu uso para prescrição de exercício aeróbio ainda é limitado. Objetivo Analisar a frequência cardíaca (FC) dos estágios do TF e no pico do teste de caminhada de 6 minutos (TC6min) como parâmetro para a prescrição de exercício aeróbio comparando com a FC no primeiro e segundo limiares ventilatórios (LV1 e LV2) do teste cardiopulmonar de exercício (TCPE). Métodos Pacientes com doença cardiovascular compareceram a 3 dias de avaliação: 1) anamnese e TCPE; 2) TC6min; e 3) TF. Foram usados ANOVA unidirecional de medidas repetidas ou teste de Friedman para comparar a FC no LV1 e LV2 com a FC nos estágios do TF: último positivo (TF+), primeiro equívoco (TF±) e negativo (TF−) e no pico do TC6min. O teste de Pearson ou Spearman avaliou se há correlação entre FC em LVs, estágios do TF e TC6min. A significância estatística foi fixada em 5%. Resultados O estudo incluiu 22 pacientes cardíacos (13 homens, 61 ± 8 anos). A FC no LV1 foi semelhante à FC no TF+ (p = 0,987) e TF± (p = 0,154), e moderadamente correlacionada com o TF+ (r = 0,479, p = 0,024). A FC no LV2 foi semelhante ao TF− (p = 0,383), com forte correlação (r = 0,757, p < 0,001). A FC no pico do TC6min foi significativamente diferente da FC no TF+, TF± e LV1 (p = 0,001, p = 0,005 e p < 0,001, respectivamente), mas semelhante ao TF− (p = 0,68). Conclusões A FC no TF+ e TF− reflete a FC no LV1 e LV2, respectivamente, diferentemente do TC6min, que foi semelhante apenas ao LV2. O TF pode ser um teste objetivo para auxiliar a prescrição de exercício aeróbio na reabilitação cardíaca.

Abstract Background Although the Talk Test (TT) is a reliable and low-cost test, its use for aerobic exercise prescription is still limited. Objective To analyze the heart rate (HR) in the stages of the TT and at the peak of the 6-minute walk test (6MWT) as a parameter to prescribe aerobic exercise compared with HR at the first and second ventilatory thresholds (VT1 and VT2) of cardiopulmonary exercise test (CPET). Methods Individuals with cardiovascular disease attended three assessment days: 1) anamnesis and CPET; 2) 6MWT; and 3) TT. One-way repeated measures ANOVA or Friedman's test were used to compare HR at VT1 and VT2 with HR at TT stages: last positive (TT+), first equivocal (TT±), and negative (TT−), and at the peak of the 6MWT. Pearson's or Spearman's test assessed correlations between HR at VTs, TT stages, and 6MWT. Statistical significance was set at 5%. Results The study included 22 cardiac patients (13 men, 61 ± 8 years). HR at VT1 was similar to HR at TT+ (p = 0.987) and TT± (p = 0.154), and moderately correlated with TT+ (r = 0.479, p = 0.024). HR at VT2 was similar to TT− (p = 0.383), with a strong correlation (r = 0.757, p < 0.001). HR at the peak of the 6MWT was significantly different from HR at TT+, TT±, and VT1 (p = 0.001, p = 0.005, and p < 0.001, respectively) but similar to TT− (p = 0.68). Conclusions HR at TT+ and TT− reflect HR at VT1 and VT2, respectively, differently from 6MWT, which was similar only to VT2. TT may be an objective test to assist aerobic exercise prescription in cardiac rehabilitation.

Can RR intervals editing and selection techniques interfere with the analysis of heart rate variability?

BACKGROUND: Oscillation between successive sinus beats or RR intervals, termed heart rate variability, is an important marker of autonomic function of the heart. However, its analysis may be influenced by the database recorded based on the occurrence of interference. OBJECTIVE: To evaluate if the techniques of identification and editing of artifacts, as well as the selection methods of RR intervals, can interfere with heart rate variability analysis. METHODS: The RR intervals of 56 subjects (30 aortic stenosis patients, 14 physically active individuals, 12 amateur athletes) were recorded for 10min using a heart rate monitor. Values with differences greater than 20%, higher than three standard deviations or outside of the normal curve (95% confidence interval) were considered artifacts. These points were corrected through data replacement, adjacent, linear and polynomial interpolation, or excluded. Then, the 256 highest stability points and the last 5min of recordings were chosen. The software programs, Kubios HRV and GraphPAD, were used to calculate and to analyze the indices of heart rate variability, respectively. RESULTS: Strong agreement was observed among the identification algorithms; there was no difference between the correction techniques (p=0.95); and the selection methods exhibited different sections (p<0.01) with a direct influence on approximated entropy (p<0.05). CONCLUSION: With short-term recordings, selection methods may interfere with the non-linear heart rate variability analysis. The confidence interval, the replacement by the average of previous data and the selection of 256 of the highest stability points of the signal seem to be the most adequate procedures to treat the data with prior to analysis.