Cardiovascular and Pulmonary Responses to Acute Use of Electronic Nicotine Delivery Systems and Combustible Cigarettes in Long-Term Users.

BACKGROUND: The acute cardiovascular and pulmonary effects of contemporary electronic nicotine delivery systems (ENDS) in long-term users are not known. RESEARCH QUESTION: What are the cardiovascular and pulmonary responses to an acute 15-min product use challenge with ENDS and combustible cigarettes in regular nicotine-containing product users compared with control participants who do not use tobacco or vape? STUDY DESIGN AND METHODS: Observational challenge study before and after nicotine-containing product use of 395 individuals who used ENDS exclusively (n = 164; exhaled carbon monoxide level, < 5 parts per million [ppm]; positive urine NicCheck I [Mossman Associates] results, 82%; fourth-generation ENDS), participants who smoked cigarettes exclusively (n = 117; carbon monoxide level, > 5 ppm; positive urine NicCheck I results), and control participants (n = 114; carbon monoxide level, < 5 ppm; negative urine NicCheck I results). RESULTS: During the 15-min product challenge, cigarette users took a median of 14.0 puffs (interquartile range [IQR], 9.3 puffs); ENDS users took 9.0 puffs (IQR, 7.5 puffs; P < .001). After product challenge, compared with control participants, ENDS users showed greater increases in adjusted mean differences in systolic BP (5.6 mm Hg [95% CI, 4.4-6.8 mm Hg] vs 2.3 mm Hg [95% CI, 0.8-3.8 mm Hg]; P = .001), diastolic BP (4.2 mm Hg [95% CI, 3.3-5.0 mm Hg] vs 2.0 mm Hg [95% CI, 1.1-3.0 mm Hg; P = .003), and heart rate (4.8 beats/min [95% CI, 4.0-5.6 beats/min] vs -1.3 beats/min [95% CI, -2.2 to -0.3 beats/min]; P < .001) and greater reductions in brachial artery diameter (-0.011 cm [95% CI, -0.013 to 0.009 cm] vs -0.006 cm [95% CI, -0.004 to -0.009 cm]; P = .003), time-domain heart rate variability (-7.2 ms [95% CI, -10.5 to -3.7 ms] vs 3.6 ms [95% CI, 1.6-9.3 ms]; P = .001), and FEV1 (ENDS: -4.1 [95% CI, -5.4 to -2.8] vs control participants: -1.1 [95% CI, -2.7 to 0.6]; P = .005) with values similar to those of cigarette users. ENDS users performed worse than control participants on all exercise parameters, notably metabolic equivalents (METs; adjusted mean difference, 1.28 METs [95% CI, 0.73-1.83 METs]; P < .001) and 60-s heart rate recovery (adjusted mean difference, 2.9 beats/min [95% CI, 0.7-5.0 beats/min]; P = .008). INTERPRETATION: ENDS users had acute worsening of blood pressure, heart rate, and heart rate variability, as well as vasoconstriction, impaired exercise tolerance, and increased airflow obstruction after vaping, compared to control participants. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT03863509; URL: www. CLINICALTRIALS: gov.

Aortic Stenosis: Risk Stratification and Timing of Surgery.

PURPOSE OF REVIEW: This review summarizes the current management of patients with newly diagnosed aortic stenosis. RECENT FINDINGS: Recent developments include detection of early myocardial dysfunction using serum B-type natriuretic peptide levels and global longitudinal strain, as well as ongoing trials of transcatheter aortic valve replacement in asymptomatic patients and patients with moderate aortic stenosis complicated by symptoms or left ventricular systolic dysfunction. Given the high mortality associated with severe symptomatic aortic stenosis, all symptomatic patients should be referred for aortic valve replacement. Asymptomatic patients with left ventricular systolic dysfunction, abnormal exercise stress test, high degree of stenosis, rapid disease progression, or elevated serum B-type natriuretic peptide level may also have an indication for valve replacement, based on established criteria. The progress in management of severe aortic stenosis has been in the direction of earlier detection and earlier valve replacement.

Is Exercise Stress Testing Useful for Risk Stratification in Anomalous Aortic Origin of a Coronary Artery?

Data on maximal exercise-stress-testing (m-EST) in anomalous-aortic-origin-of-coronary-arteries (AAOCA) is limited and correlation with stress perfusion imaging has not been demonstrated. AAOCA patients ≤20 years were prospectively enrolled from 6/2014-01/2020. A m-EST was defined as heart rate >85%ile on ECG-EST and respiratory-exchange-ratio ≥1.05 on cardiopulmonary-exercise-testing (CPET). Abnormal m-EST included significant ST-changes or high-grade arrhythmia, V̇O2max and/or O2 pulse <85% predicted, or abnormal O2 pulse curve. A (+) dobutamine-stress cardiac-magnetic-resonance-imaging (+DS-CMR) had findings of inducible-ischemia. Outcomes: (1) Differences in m-EST based on AAOCA-type; (2) Assuming DS-CMR as gold-standard for detection of inducible ischemia, determine agreement between m-EST and DS-CMR. A total of 155 AAOCA (right, AAORCA = 126; left, AAOLCA = 29) patients with a median (IQR) age of 13 (11-15) years were included; 63% were males and a m-EST was completed in 138 (89%). AAORCA and AAOLCA had similar demographic and m-EST characteristics, although AAOLCA had more frequently evidence of inducible ischemia on m-EST (P = 0.006) and DS-CMR (P = 0.007). Abnormal O2 pulse was significantly associated with +DS-CMR (OR 5.3, 95% CI 1.6-18,P = 0.005). Sensitivity was increased with addition of CPET to ECG-EST (to 58% from 19%). There was no agreement between m-EST and DS-CMR for detection of inducible ischemia. A m-EST has very low sensitivity for detection of inducible ischemia in AAOCA, and sensitivity is increased with addition of CPET. Stress perfusion abnormalities on DS-CMR were notconcordant with m-EST findings and adjunctive testing should be considered for clinical decision making in AAOCA.

Sex-Specific Impairment of Cardiac Functional Reserve in HFpEF: Insights From the HFpEF Stress Trial.

Background: Heart failure with preserved ejection fraction (HFpEF) has been observed to have a twice as high prevalence in women compared to men with similar predisposing risk factors between both sexes. Objectives: This study aimed to identify sex-specific pathophysiological features in HFpEF using rest and exercise stress right heart catheterization (RHC), echocardiography and cardiovascular magnetic resonance imaging (CMR). Methods: Seventy-five patients with exertional dyspnea, preserved ejection fraction (EF) (≥50%), and signs of diastolic dysfunction on echocardiography were prospectively recruited in the HFpEF Stress Trial. Patients underwent RHC, echocardiography and CMR at rest and during exercise stress. Patients were diagnosed with HFpEF and noncardiac dyspnea according to RHC measurements. Results: After exclusion, the final study cohort comprised 68 patients (females n = 44, males n = 24) with a mean age of 66.9 ± 9.7 years. Compared to men, women with HFpEF revealed lower right ventricular stroke volumes during exercise stress (females 38.1 vs males 50.4 mL/m2 BSA; P = 0.011). This was accompanied by a decreasing left atrial EF in women but not men comparing resting to exercise conditions (females -2.7% vs males 2.5%, P = 0.020) and impaired left ventricular filling (females 35.5 vs males 44.2 mL/m2 BSA, P = 0.017) in women with HFpEF during exercise stress. These sex-specific differences were not present in noncardiac dyspnea. Conclusions: Women with HFpEF demonstrate sex-specific functional alterations of right ventricular, left atrial, and left ventricular function during exercise stress. This unique pathophysiology represents a sex-specific diagnostic target, which may allow early identification of women with HFpEF for future individualized therapeutic approaches.

Age and Sex Differences and Temporal Trends in the Use of Invasive and Noninvasive Procedures in Patients Hospitalized With Acute Myocardial Infarction.

Background Few studies have examined age and sex differences in the receipt of cardiac diagnostic and interventional procedures in patients hospitalized with acute myocardial infarction and trends in these possible differences during recent years. Methods and Results Data from patients hospitalized with a first acute myocardial infarction at the major medical centers in the Worcester, Massachusetts, metropolitan area were utilized for this study. Logistic regression analysis was used to examine age (<55, 55-64, 65-74, and ≥75 years) and sex differences in the receipt of echocardiography, exercise stress testing, coronary angiography, percutaneous coronary interventions, and coronary artery bypass graft surgery, and trends in the use of those procedures during patients' acute hospitalization, between 2005 and 2018, while adjusting for important confounding factors. The study population consisted of 1681 men and 1154 women with an initial acute myocardial infarction who were hospitalized on an approximate biennial basis between 2005 and 2018. A smaller proportion of women underwent cardiac catheterization, percutaneous coronary intervention, and coronary artery bypass graft surgery, while there were no sex differences in the receipt of echocardiography and exercise stress testing. Patients aged ≥75 years were less likely to undergo cardiac catheterization, percutaneous coronary intervention, and coronary artery bypass graft surgery, but were more likely to receive echocardiography compared with younger patients. Between 2005 and 2018, the use of echocardiography and coronary artery bypass graft surgery nonsignificantly increased among all age groups and both sexes, while the use of cardiac catheterization and percutaneous coronary intervention increased nonsignificantly faster in women and older patients. Conclusions We observed a continued lower receipt of invasive cardiac procedures in women and patients aged ≥75 years with acute myocardial infarction, but age and sex gaps associated with these procedures have narrowed during recent years.

Relationship Between Cardiorespiratory Fitness, Baseline Blood Pressure and Hypertensive Response to Exercise in the Ferrari Corporate Population.

AIM: To evaluate the incidence and clinical significance of impaired cardiorespiratory fitness (CRF) and the association with baseline blood pressure (BP) levels and hypertensive response to exercise (HRE). METHODS: A cross-sectional study was conducted on a total sample of 2058 individuals with a mean age of 38 ± 9 years, enrolled for the first time at the Ferrari corporate wellness program "Formula Benessere", including a maximal exercise stress testing (EST). BP and heart rate (HR) values were obtained from EST at rest, during exercise and recovery time. CRF was arbitrarily classified according to estimated VO2 max in optimal, normal, mildly and moderately reduced. RESULTS: One-hundred and thirty-nine individuals of 2058 (6.7%) showed a moderate CRF reduction assessed by EST. Subjects with elevated resting and/or exercise BP showed a worse CRF than those with normal BP levels, also after the adjustment for age, sex, body mass index, smoking habits, peak SBP and DBP. Seventy-seven individuals (3.7%) showed an HRE during EST, with normal baseline BP levels. CONCLUSION: About 7% of a corporate population showed a significantly reduced CRF, assessed by EST. Individuals with lower levels of CRF have higher resting and/or peak exercising BP values after adjusting for co-variables. This study expands the role of EST outside of traditional ischemic CVD evaluation, towards the assessment of reduced CRF and HRE in the general population, as a possible not evaluated CV risk factor.

Exercise testing for children with cystic fibrosis: A systematic review.

BACKGROUND: Exercise testing is routinely used to measure exercise capacity in children with cystic fibrosis (CF). Various tests are available, however the psychometric properties of these measures have not been systematically reviewed for this population. METHOD: A systematic search of electronic databases (PubMed, Web of Science, Medline, CINHAL, Cochrane, and PEDro) was performed to identify papers that: (a) reported original psychometric data, (b) examined a measure of exercise capacity, (c) examined children with CF aged eight to 18 years; and (d) were published in English after 1950. The level of psychometric evidence was evaluated using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist. RESULTS: Searches identified 1025 papers. Forty-six papers were included, covering 15 tests: incremental cardiopulmonary exercise test using a cycle ergometer (CPET(cycle)) or treadmill (CPET(treadmill)), 6 minute walk test (6MWT), modified shuttle test (MST), 3-minute step test (3MST), 2 minute walk test (2MWT), Bratteby walk test, intermittent sprint test, speed ramp test, incremental step test, forward-backwards jump test (FBJT), astride jump test (AJT), motor quotient test, Munich fitness test, and Glittre ADL test. CONCLUSION: There is a plethora of exercise tests available with varying psychometric robustness. The CPET, 6MWT, and MST have fair to good psychometric properties, but each with their clinical advantages and limitations. Thus, a Selection Guide was developed to assist clinicians and researchers in selecting the most appropriate exercise test for various situations.

Comparative Cardiorespiratory Fitness in Children: Racial Disparity May Begin Early in Childhood.

African American (AA) adults are reported to have lower levels of cardiorespiratory fitness (CRF) as compared to Caucasian adults. CRF is linked to cardiovascular morbidity and mortality. We hypothesized that the disparities start early in childhood. This was a retrospective analysis of the cardiopulmonary exercise test (CPET). We included normal healthy children, ≤ 18 years of age, who had normal electrocardiograms and normal cardiac function. We excluded patients with congenital heart disease, obesity and suboptimal exercise test. The entire cohort was divided into two groups based on race (Caucasian vs. AA) and then further subcategorized by gender. The cohort of 248 patients had a mean ± SD age of 14.4 ± 2.1 years. 158 (60.8%) were males and 158 (60.8%) were Caucasians. Oxygen consumption was higher among Caucasian children when compared to the AA children (48.7 ± 7.9 vs. 45.4 ± 7 mL/kg/min, p = 0.01). This racial disparity continued to persist when comparisons were performed separately for girls and boys. Upon comparing the four groups, the AA females were found to have the lowest values of VO2max, exercise time and METS (p = 0.001). Thus, in conclusion, the AA children have significantly lower level of CRF, as measured by VO2max and exercise time. The racial disparity is independent of gender. African American females show the lowest level of aerobic capacity. The findings of our study suggest that the racial disparity in the CRF levels seen in the adult population may begin early in childhood.

Electrocardiographic exercise testing in adults: performance and interpretation. An expert opinion of the Polish Cardiac Society Working Group on Cardiac Rehabilitation and Exercise Physiology.

Electrocardiographic (ECG) exercise stress test has been a major diagnostic test in cardiology for several decades. Ongoing technological advances that have led to a wide use of imaging techniques and development of new guidelines have called for a revised and updated approach to the technique and interpretation of the ECG exercise testing. The present document outlines an expert opinion of the Polish Cardiac Society Working Group on Cardiac Rehabilitation and Exercise Physiology regarding the performance and interpretation of ECG exercise testing in adults. We discussed technical requirements and necessary equipment for the exercise testing laboratory as well as healthcare personnel competencies necessary to supervise ECG exercise testing and fully interpret test findings. Broad indications for ECG exercise testing include diagnostic assessment of coronary artery disease (CAD), including pre-test probability of CAD, evaluation of functional disease severity and risk strati- fication in patients with established CAD, assessment of response to treatment, evaluation of exercise-related symptoms and exercise capacity, patient evaluation before exercise training/cardiac rehabilitation, and risk stratification prior to non-cardiac surgery. ECG exercise testing is safe if indications and contraindications are observed, testing is appropriately monitored, and indications for test termination are clearly established. The exercise protocol should be adjusted to the expected exercise capacity of a patient so as to limit the duration of exercise to 8-12 min. Clinical, haemodynamic, and ECG response to exercise is evaluated during the test. The test report should include information about the exercise protocol used, reason for test termination, perceived exertion, presence/severity of anginal symptoms, peak exercise capacity or tolerated workload in relation to the predicted exercise capacity, heart rate response, and the presence or absence of ST-T changes. The test report should conclude with a summary including clinical and ECG assessment.

Human Cardiac 31P-MR Spectroscopy at 3 Tesla Cannot Detect Failing Myocardial Energy Homeostasis during Exercise.

Phosphorus-31 magnetic resonance spectroscopy (31P-MRS) is a unique non-invasive imaging modality for probing in vivo high-energy phosphate metabolism in the human heart. We investigated whether current 31P-MRS methodology would allow for clinical applications to detect exercise-induced changes in (patho-)physiological myocardial energy metabolism. Hereto, measurement variability and repeatability of three commonly used localized 31P-MRS methods [3D image-selected in vivo spectroscopy (ISIS) and 1D ISIS with 1D chemical shift imaging (CSI) oriented either perpendicular or parallel to the surface coil] to quantify the myocardial phosphocreatine (PCr) to adenosine triphosphate (ATP) ratio in healthy humans (n = 8) at rest were determined on a clinical 3 Tesla MR system. Numerical simulations of myocardial energy homeostasis in response to increased cardiac work rates were performed using a biophysical model of myocardial oxidative metabolism. Hypertrophic cardiomyopathy was modeled by either inefficient sarcomere ATP utilization or decreased mitochondrial ATP synthesis. The effect of creatine depletion on myocardial energy homeostasis was explored for both conditions. The mean in vivo myocardial PCr/ATP ratio measured with 3D ISIS was 1.57 ± 0.17 with a large repeatability coefficient of 40.4%. For 1D CSI in a 1D ISIS-selected slice perpendicular to the surface coil, the PCr/ATP ratio was 2.78 ± 0.50 (repeatability 42.5%). With 1D CSI in a 1D ISIS-selected slice parallel to the surface coil, the PCr/ATP ratio was 1.70 ± 0.56 (repeatability 43.7%). The model predicted a PCr/ATP ratio reduction of only 10% at the maximal cardiac work rate in normal myocardium. Hypertrophic cardiomyopathy led to lower PCr/ATP ratios for high cardiac work rates, which was exacerbated by creatine depletion. Simulations illustrated that when conducting cardiac 31P-MRS exercise stress testing with large measurement error margins, results obtained under pathophysiologic conditions may still lie well within the 95% confidence interval of normal myocardial PCr/ATP dynamics. Current measurement precision of localized 31P-MRS for quantification of the myocardial PCr/ATP ratio precludes the detection of the changes predicted by computational modeling. This hampers clinical employment of 31P-MRS for diagnostic testing and risk stratification, and warrants developments in cardiac 31P-MRS exercise stress testing methodology.

The short-term impact of the catheter ablation on noninvasive autonomic nervous system parameters in patients with paroxysmal atrial fibrillation.

BACKGROUND: The autonomic nervous system (ANS) is a potentially potent modulator of the initiation and perpetuation of atrial fibrillation (AF), whereas the presence of AF can activate and alter the ANS. The catheter ablation of AF (AFCA) may cause the cardiac ANS dysfunction, whereas restoration of sinus rhythm or sympathovagal imbalance by AFCA can reverse this process. Our principal goal was to investigate the short-term effect of AFCA on ANS functions evaluated by noninvasive chronotropic (CI), resting heart rate (RHR), and heart rate recovery (HRR) indices. METHOD: A total of 45 patients were enrolled with symptomatic, drug refractory paroxysmal AF undergoing first cryoballoon (CB) pulmonary vein antrum isolation (PVAI) with one 28-mm CB using single 3-minute freeze techniques without bonus applications. All patients underwent symptom-limited exercise treadmill testing to evaluate noninvasive parameters of ANS before PVAI. For those patients who remained in sinus rhythm, an additional exercise test was repeated after 1 and 3 months after discharge. RESULTS: The autonomic CI and RHR/HRR indices were impaired after PVAI and persisted post-PVAI 3 months. However, these parameters were not different in patients with and without recurrence. CONCLUSION: This study demonstrated that the successful AFCA might concurrently impair the ANS parameters. The autonomic imbalance between the sympathetic and parasympathetic activity after AFCA could either become antiarrhythmic and/or proarrhythmic based on which of the two components was going to prevail after successful AFCA. The impaired ANS balance after PVAI might also be another hypothetical mechanism for AF recurrence particularly in the absence of PV reconnection.

Myoadenylate deaminase deficiency: a frequent cause of muscle pain A case detected by exercise testing.

Myoadenylate deaminase deficit (MAD, MIM#615511) is the most common cause of metabolic myopathies with an estimated prevalence of 1-2% in the general population. We report the case of a 39-year-old man suffering from severe skeletal muscle pain that had developed gradually for 4 years. A moderate increase in creatine kinase (CK) was the only biological sign observed. This study takes a closer look at a common but poorly known pathology and highlights the interest of the dynamic metabolic investigations carried out during exercise stress test with a cycle ergometer. Our non-invasive clinical and biological examination, at the interface between physiology and biology, disclosed the total absence of a physiological increase in plasma ammonia evocative of MAD. However, MAD was later confirmed by histochemistry and molecular studies, which revealed the presence of the recurrent homozygous pathogenic variant affecting the adenosine monophosphate deaminase 1 gene (AMPD1) in most patients with MAD.

Gender disparities in the functional significance of anemia among apparently healthy adults.

BACKGROUND: Data on the functional impact of anemia on cardiorespiratory fitness (CRF) and survival in healthy individuals are limited. Our aim was to evaluate the association between anemia thresholds, low CRF, and survival in otherwise healthy adults. METHODS: Study population included 16 334 apparently healthy subjects attending annual periodic health screening examinations (71 200 annual visits), including exercise stress testing (EST). Anemia was defined by the World Health Organization (WHO) or Beutler and Waalens' (BW) criteria. Low CRF was defined as the lowest fitness quintile according to the Bruce protocol. RESULTS: The mean age was 46±10 years, and 70% were men. Mean Hb levels were 13±1 and 15±1 among women and men, respectively, with higher proportion of anemia among women. The majority of anemic subjects had mild anemia. When analyzing repeated annual visits, anemia was associated with a significant 39% and 64% increased risk of low CRF according the WHO and BW criteria only in women (n=18 672). Baseline anemia at first visit was associated with 2.6- and 1.9-fold increased risk of all-cause mortality using the WHO and BW criteria, exclusively in men (n=11 511). CONCLUSIONS: Overall, the functional and prognostic impact of anemia is gender dependent, based on the WHO and BW arbitrary criteria, suggesting differing mechanism and responses.

Osteoprotegerin concentrations in patients with suspected reversible myocardial ischemia: observations from the Akershus Cardiac Examination (ACE) 1 Study.

Increased circulating osteoprotegerin (OPG) levels have been associated with the prevalence and severity of coronary artery disease and the risk of cardiovascular death. OPG is a cytokine of the tumor necrosis factor receptor superfamily and is expressed in various cell types in the body, including osteoblasts, inflammatory cells, vascular smooth muscle cells/endothelial cells and cardiomyocytes. The main sources determining OPG levels in the circulation however, are not well understood, and whether reversible myocardial ischemia influences OPG levels are not known. Accordingly, OPG levels were measured in 198 patients referred for exercise stress testing and myocardial perfusion imaging (MPI). In addition OPG levels were measured in 8 healthy control subjects performing a maximal bicycle stress test. Plasma samples were collected before, immediately after, 1.5h and 4.5h after exercise stress testing with MPI. OPG levels at baseline were not different in patient with reversible myocardial ischemia (n=19) and patients without reversible ischemia (n=179) (4.7 [3.6-5.5]pmol/L vs. 4.3 [3.4-5.2]pmol/L, p=0.21), and there was an increase in OPG levels immediately after exercise regardless of whether or not the patient had reversible ischemia on MPI (absolute increase: 0.2 [0-0.55]pmol/L vs. 0.3 [0-0.5]pmol/L, p=0.72). OPG levels also increased immediately after stress in the 8 control subjects (3.5 (3.2-3.8)pmol/L at baseline to 3.8 (3.5-4.7), p=0.008). In conclusion, OPG levels increase acutely during exercise stress testing, but this increase is likely caused by mechanisms other than myocardial ischemia.

The diagnostic yield of exercise stress testing as a screening tool for subclinical coronary artery disease in patients with moderate to severe obstructive sleep apnea.

STUDY OBJECTIVE: To address the yield of routine exercise stress testing as a screening tool for subclinical coronary artery disease (CAD) in patients with moderate to severe obstructive sleep apnea (OSA). DESIGN AND SETTING: A cross-sectional study in a university hospital. PARTICIPANTS: Of 380 consecutive patients with OSA, data from 206 subjects (mean apnea-hypopnea index [AHI] 41 ± 21 events/h) were studied; data from 78 with a history of CAD and 96 with mild OSA (AHI 5-15 events/h) were excluded. MEASUREMENTS: Routine exercise stress testing. RESULTS: Six subjects could not reach maximal exercise capacity. Of the remaining 200 patients, the results of exercise stress testing were normal in 189. Three had a positive stress test, with coronary angiography confirming the diagnosis of CAD. Eight patients had suspected positive findings on the stress test, but the results of the myocardial perfusion study were negative. CONCLUSION: The prevalence of subclinical CAD in this selected population with OSA was 1.5%, which is not higher than that in a general population. Our results do not support the routine use of exercise stress testing in patients with moderate to severe OSA who do not have symptoms of CAD.

Correlação entre o teste de caminhada de 6 minutos e as variáveis do teste ergométrico em pacientes com insuficiência cardíaca: estudo piloto / Correlation between six-minute walk test and exercise stress testing variables in patients with heart failure: a pilot study

Objetivo: Correlacionar a distância percorrida no teste de 6 minutos (TC6M) com as variáveis do testeergométrico (TE). Métodos: Foram estudados 21 pacientes, sendo 66%brancos, 62% homens, com média de idade de 60±11 anos, 38% diabéticos e com dislipidemia e 57% com hipertensãoarterial, com insuficiência cardíaca isquêmica (33%) e nãoisquêmica(67%), nas classes funcionais II (90%) e III (10%) da NYHA, com fração de ejeção = 0,35±0,058, utilizandoseo teste de caminhada de 6 minutos (TC6M) e o teste ergométrico (Bruce modificado). Foram excluídos ospacientes não otimizados com terapêutica medicamentosa,problemas ortopédicos, doença vascular periférica ou quaisquer limitações para esforço. Analisou-se no TC6Ma distância total percorrida, sendo o paciente submetido a 3 testes com intervalos de 20 minutos. Foi comparado o valor de distância média alcançada no TC6M com a distância percorrida no teste ergométrico; o consumo deoxigênio máximo (VO2) e o equivalente metabólico máximo (MET) do TE. Para a análise estatística foram utilizados: o teste do qui-quadrado, de Mann-Whitney e a correlação de Pearson. Resultados: Houve significativas correlações positivas entre a distância percorrida no TC6M e a distância percorrida no teste de esforço (p=0,0001; r=0,76); e entreo VO2 máximo (p=0,001; r=0,68) e o MET máximo (p=0,001; r=0,68) neste grupo de pacientes. Conclusão: O TC6M é um teste reprodutível, de fácil realização e de baixo custo que pode ser utilizado para a avaliação de pacientes com IC, podendo fornecer informações valiosas que normalmente são obtidassomente com o TE. O aumento da amostra poderá determinar o verdadeiro valor dessas informações.

Objective: To correlate the distance on Six-minute walk test (6-MWT) with parameters obtained during exercise stress testing (EST) with a Bruce-modified protocol. Methods: We studied 21 patients, of whom 66% were white, 62% male, age 60±11 years, 38% diabetic and with dyslipidemia and 57% with arterial hypertension, 33% with with ischemic and 67% with nonischemicHF, NYHA class II (90%) and III (10%), with ejection fraction= 0.35±0.058. We excluded patients with suboptimal therapy, orthopedic disability, peripheral vascular disease or unable to exercise. Patients weresubmitted to 6-MWT for three times, with a 20-minute interval, and mean distance value was considered forcomparisons with distance, maximal oxygen uptake (maxVO2) and maximal metabolic equivalent (MET) during EST. Chi-square, Mann-Whitney and Pearson’scorrelation tests were used. Results: We observed significant positive correlationsbetween mean distance on 6-MWT and EST distance (p=0.0001; r=0.76), EST maxVO2 (p=0.001; r=0.68) and EST MET (p=0.001; r=0.68). Conclusion: On heart failure patients, 6-MWT is a reproducible, low-cost and easily obtainable test that can provide valuable information, usually only available on EST. Future studies with larger samplesizes will validate the present study results.