BackgroundIt is important to include large sample sizes and different factors that influence the six-minute walking distance (6MWD) in order to propose reference equations for the six-minute walking test (6MWT). ObjectiveTo evaluate the influence of anthropometric, demographic, and physiologic variables on the 6MWD of healthy subjects from different regions of Brazil to establish a reference equation for the Brazilian population. MethodIn a multicenter study, 617 healthy subjects performed two 6MWTs and had their weight, height, and body mass index (BMI) measured, as well as their physiologic responses to the test. Delta heart rate (∆HR), perceived effort, and peripheral oxygen saturation were calculated by the difference between the respective values at the end of the test minus the baseline value. ResultsWalking distance averaged 586±106m, 54m greater in male compared to female subjects (p<0.001). No differences were observed among the 6MWD from different regions. The quadratic regression analysis considering only anthropometric and demographic data explained 46% of the variability in the 6MWT (p<0.001) and derived the equation: 6MWDpred=890.46-(6.11×age)+(0.0345×age2)+(48.87×gender)-(4.87×BMI). A second model of stepwise multiple regression including ∆HR explained 62% of the variability (p<0.0001) and derived the equation: 6MWDpred=356.658-(2.303×age)+(36.648×gender)+(1.704×height)+(1.365×∆HR). ConclusionThe equations proposed in this study, especially the second one, seem adequate to accurately predict the 6MWD for Brazilians.

BackgroundDespite the epidemic of cardiovascular disease and the benefits of cardiac rehabilitation (CR), availability is known to be insufficient, although this is not quantified. This study ascertained CR availability, volumes and its drivers, and density.MethodsA survey was administered to CR programs globally. Cardiac associations and local champions facilitated program identification. Factors associated with volumes were assessed using generalized linear mixed models, and compared by World Health Organization region. Density (i.e. annual ischemic heart disease [IHD] incidence estimate from Global Burden of Disease study divided by national CR capacity) was computed.FindingsCR was available in 111/203 (54.7%) countries; data were collected in 93 (83.8% country response; N = 1082 surveys, 32.1% program response rate). Availability by region ranged from 80.7% of countries in Europe, to 17.0% in Africa (p < .001). There were 5753 programs globally that could serve 1,655,083 patients/year, despite an estimated 20,279,651 incident IHD cases globally/year. Volume was significantly greater where patients were systematically referred (odds ratio [OR] = 1.36, 95% confidence interval [CI] = 1.35–1.38) and programs offered alternative models (OR = 1.05, 95%CI = 1.04–1.06), and significantly lower with private (OR = .92, 95%CI = .91–.93) or public (OR = .83, 95%CI = .82–84) funding compared to hybrid sources.Median capacity (i.e., number of patients a program could serve annually) was 246/program (Q25-Q75 = 150–390). The absolute density was one CR spot per 11 IHD cases in countries with CR, and 12 globally.InterpretationCR is available in only half of countries globally. Where offered, capacity is grossly insufficient, such that most patients will not derive the benefits associated with participation.

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BackgroundCardiac rehabilitation (CR) is a clinically-effective but complex model of care. The purpose of this study was to characterize the nature of CR programs around the world, in relation to guideline recommendations, and compare this by World Health Organization (WHO) region.MethodsIn this cross-sectional study, a piloted survey was administered online to CR programs globally. Cardiac associations and local champions facilitated program identification. Quality (benchmark of ≥ 75% of programs in a given country meeting each of 20 indicators) was ranked. Results were compared by WHO region using generalized linear mixed models.Findings111/203 (54.7%) countries in the world offer CR; data were collected in 93 (83.8%; N = 1082 surveys, 32.1% program response rate). The most commonly-accepted indications were: myocardial infarction (n = 832, 97.4%), percutaneous coronary intervention (n = 820, 96.1%; 0.10), and coronary artery bypass surgery (n = 817, 95.8%). Most programs were led by physicians (n = 680; 69.1%). The most common CR providers (mean = 5.9 ± 2.8/program) were: nurses (n = 816, 88.1%; low in Africa, p < 0.001), dietitians (n = 739, 80.2%), and physiotherapists (n = 733, 79.3%). The most commonly-offered core components (mean = 8.7 ± 1.9 program) were: initial assessment (n = 939, 98.8%; most commonly for hypertension, tobacco, and physical inactivity), risk factor management (n = 928, 98.2%), patient education (n = 895, 96.9%), and exercise (n = 898, 94.3%; lower in Western Pacific, p < 0.01). All regions met ≥ 16/20 quality indicators, but quality was < 75% for tobacco cessation and return-to-work counseling (lower in Americas, p = < 0.05).InterpretationThis first-ever survey of CR around the globe suggests CR quality is high. However, there is significant regional variation, which could impact patient outcomes.

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AimsThe effects of exercise training in chronic heart failure are well established, however, they have not been evaluated in Chagas cardiomyopathy (ChC). We sought to determine the effects of exercise training on functional capacity, health-related quality of life (HQoL), and brain natriuretic peptide (BNP) levels in patients with ChC. Methods and resultsThis randomized, controlled, single-blind trial included 40 patients with ChC (age 49.5 + 7.8 years, 57.5% male) who did not practice regular exercise. All patients were assessed, at baseline and at the end of the study, by exercise test (VO 2 and exercise time), six-minute walk test (6MWT), Goldman Specific Activity Scale (SAS), HQoL, and BNP levels. Patients were randomized to inactive control group (ICG ¼ 19) or exercise training group (ETG ¼ 21). Exercise training group patients underwent 12 weeks of exercise training: walking for up to 30 min (intensity 50-70% HR reserve + HR at rest) and warm-up and cooling-down exercising, three times a week. The data were analysed for delta values (D¼ end 2 baseline). After intervention, compared with the ICG, the ETG had significant increases in functional parameters including, DVO 2 (6.5 vs. 2.8 mL/kg/min, P ¼ 0.001), D exercise time (2.9 vs.1.1 min, P , 0.001), D6MWT distance (83.5 vs. 2.0 m, P ¼ 0.001) improved DSAS (8 vs. 1 patient, P ¼ 0.008), and HQoL: D domains vitality (7.5 vs. 0 points, P ¼ 0.013), D emotional aspects (16.7 vs. 0 points, P ¼ 0.012), and D mental health (16.1 vs. 0 points, P ¼ 0.031). There was no difference in BNP levels. ConclusionIn patients with ChC, exercise training was associated with a major improvement in functional capacity and HQoL without any adverse effects.--

The objective of the present study was to evaluate breathing pattern, thoracoabdominal motion and muscular activity during three breathing exercises: diaphragmatic breathing (DB), flow-oriented (Triflo II) incentive spirometry and volume-oriented (Voldyne) incentive spirometry. Seventeen healthy subjects (12 females, 5 males) aged 23 ± 5 years (mean ± SD) were studied. Calibrated respiratory inductive plethysmography was used to measure the following variables during rest (baseline) and breathing exercises: tidal volume (Vt), respiratory frequency (f), rib cage contribution to Vt (RC/Vt), inspiratory duty cycle (Ti/Ttot), and phase angle (PhAng). Sternocleidomastoid muscle activity was assessed by surface electromyography. Statistical analysis was performed by ANOVA and Tukey or Friedman and Wilcoxon tests, with the level of significance set at P < 0.05. Comparisons between baseline and breathing exercise periods showed a significant increase of Vt and PhAng during all exercises, a significant decrease of f during DB and Voldyne, a significant increase of Ti/Ttot during Voldyne, and no significant difference in RC/Vt. Comparisons among exercises revealed higher f and sternocleidomastoid activity during Triflo II (P < 0.05) with respect to DB and Voldyne, without a significant difference in Vt, Ti/Ttot, PhAng, or RC/Vt. Exercises changed the breathing pattern and increased PhAng, a variable of thoracoabdominal asynchrony, compared to baseline. The only difference between DB and Voldyne was a significant increase of Ti/Ttot compared to baseline. Triflo II was associated with higher f values and electromyographic activity of the sternocleidomastoid. In conclusion, DB and Voldyne showed similar results while Triflo II showed disadvantages compared to the other breathing exercises.