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A moderate 500-m treadmill walk for estimating peak oxygen uptake in men with NYHA class I-II heart failure and reduced left ventricular ejection fraction.

ABSTRACT: BACKGROUND:Maximal cardiopulmonary exercise testing (CPX) is the gold-standard for cardiorespiratory fitness assessment in chronic heart failure (CHF) patients. However, high costs, required medical supervision, and safety concerns make maximal exercise testing impractical for evaluating mobility-impaired adults. Thus, several submaximal walking protocols have been developed and currently used to estimate peak oxygen consumption (VO2peak) in CHF patients. However, these tests have to be performed at close to maximum exercise intensity. The aim of this study was to examine the validity of a 500-m treadmill-walking test carried out at moderate intensity for estimating VO2peak in community-dwelling adult and elderly patients with CHF and reduced left ventricular ejection fraction (HFrEF). METHODS:Forty-three clinically stable men with HFrEF (age 67.7 ± 9.2 years, and left ventricular ejection fraction, LVEF 38% ± 6%) underwent exercise testing during an outpatient cardiac rehabilitation/secondary prevention program. Each patients completed a CPX, and a moderate and self-paced (11-13/20 on the Borg scale) 500-m treadmill-walking test. Age, weight, height, walk time, and heart rate during the 500-m test were entered into prediction equations previously validated for VO2peak estimation from a 1000-m walking test in patients with cardiovascular disease and preserved LVEF. RESULTS:Directly measured and estimated VO2peak values were not different (21.6 ± 4.9 vs 21.7 ± 4.6 mL/kg/min). The comparison between measured and estimated VO2peak values yielded a correlation of R = 0.97 (SEE = 0.7 mL/kg/min, P < 0.0001). The slope and the intercept coincided with the line of identity (Passing and Bablock analysis, P = 0.50). Residuals were normally distributed, and the examination of the Bland-Altman analysis do not show systematic or proportional error. CONCLUSIONS:A moderate and self-regulated 500-m treadmill-walking test is a valid tool for VO2peak estimation in patients with HFrEF. These findings may have practical implications in the context of transitioning from clinically based programs to fitness facilities or self-guided exercise programs in adults and elderly men with HFrEF.

SUBMITTER: Mazzoni G

PROVIDER: S-EPMC5902976 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background Moderate aortic stenosis ( MAS ) has not been extensively studied and characterized, as no published study has been specifically devoted to this condition. Methods and Results We aimed to describe the characteristics of patients with MAS and to evaluate their long-term survival compared with that of the general population. This study included 508 patients (mean±SD age, 75±11 years) with MAS (aortic valve area between 1 and 1.5 cm2; mean±SD aortic valve area, 1.2±0.15 cm2) and preserved left ventricular ejection fraction. Patients were mostly (86.4%) asymptomatic or minimally symptomatic, 78.3% had hypertension, 36.2% were diabetics, and 48.3% had dyslipidemia. Each patient with MAS was matched for the average survival (per year) of all patients of the same age and same sex from our region (Somme department, north of France). During follow-up (median 47 months), 113 patients (22.2%) underwent aortic valve replacement for severe AS. The mean±SD time between inclusion and surgery was 37±22 months. During follow-up, 255 patients (50.2%) died. The 6-year survival of patients with MAS was lower than the expected survival (53±2% versus 65%). In multivariate analysis, age (hazard ratio, 1.04 [95% CI, 1.02-1.05]; P<0.001), prior atrial fibrillation (hazard ratio, 1.35 [95% CI, 1.05-1.73]; P=0.019), and Charlson comorbidity index (hazard ratio, 1.11 [95% CI, 1.05-1.18]; P=0.002) were associated with increased mortality. Aortic valve replacement was associated with better survival (hazard ratio, 0.38 [95% CI, 0.27-0.54]; P<0.001). Conclusions The results of this study show that patients with MAS present many cardiovascular risk factors, a high rate of surgery during follow-up, and increased mortality compared with the general population mainly related to associated comorbidities. Patients with MAS should, therefore, be managed for their cardiovascular risk factors and comorbidities. They require close follow-up, especially when the aortic valve area is close to 1 cm2, as aortic valve replacement performed when patients transition to severe AS and develop indications for surgery during follow-up is associated with better survival.

Project description:Aims: Evidence-based guidelines for heart failure management depend mainly on current left ventricular ejection fraction (LVEF). However, fewer studies have examined the impact of prior LVEF. Patients may enter the heart failure with midrange ejection fraction (HFmrEF) category when heart failure with preserved ejection fraction (HFpEF) deteriorates or heart failure with reduced ejection fraction (HFrEF) improves. In this study, we examined the association between change in LVEF and adverse outcomes. Methods: HFmrEF patients with at least two or more echocardiograms 3 months apart at the First Affiliated Hospital of Dalian Medical University between September 1, 2015 and November 30, 2019 were identified. According to the prior LVEF, the subjects were divided into improved group (prior LVEF < 40%), stable group (prior LVEF between 40 and 50%), and deteriorated group (prior LVEF ≥ 50%). The primary outcomes were cardiovascular death, all-cause mortality, hospitalization for worsening heart failure, and composite event of all-cause mortality or all-cause hospitalization. Results: A total of 1,168 HFmrEF patients (67.04% male, mean age 63.60 ± 12.18 years) were included. The percentages of improved, stable, and deteriorated group were 310 (26.54%), 334 (28.60%), and 524 (44.86%), respectively. After a period of follow-up, 208 patients (17.81%) died and 500 patients met the composite endpoint. The rates of all-cause mortality were 35 (11.29%), 55 (16.47%), and 118 (22.52%), and the composite outcome was 102 (32.90%), 145 (43.41%), and 253 (48.28%) for the improved, stable, and deteriorated groups, respectively. Cox regression analysis showed that the deterioration group had higher risk of cardiovascular death (HR: 1.707, 95% CI: 1.064-2.739, P = 0.027), all-cause death (HR 1.948, 95% CI 1.335-2.840, P = 0.001), and composite outcome (HR 1.379, 95% CI 1.096-1.736, P = 0.006) compared to the improvement group. The association still remained significant after fully adjusted for both all-cause mortality (HR = 1.899, 95% CI 1.247-2.893, P = 0.003) and composite outcome (HR: 1.324, 95% CI: 1.020-1.718, P = 0.035). Conclusion: HFmrEF patients are heterogeneous with three different subsets identified, each with different outcomes. Strategies for managing HFmrEF should include previously measured LVEF to allow stratification based on direction changes in LVEF to better optimize treatment.

Project description:Heart Failure (HF) significantly impacts approximately 26 million people worldwide, causing disruptions in the normal functioning of their hearts. The estimation of left ventricular ejection fraction (LVEF) plays a crucial role in the diagnosis, risk stratification, treatment selection, and monitoring of heart failure. However, achieving a definitive assessment is challenging, necessitating the use of echocardiography. Electrocardiogram (ECG) is a relatively simple, quick to obtain, provides continuous monitoring of patient's cardiac rhythm, and cost-effective procedure compared to echocardiography. In this study, we compare several regression models (support vector machine (SVM), extreme gradient boosting (XGBOOST), gaussian process regression (GPR) and decision tree) for the estimation of LVEF for three groups of HF patients at hourly intervals using 24-hour ECG recordings. Data from 303 HF patients with preserved, mid-range, or reduced LVEF were obtained from a multicentre cohort (American and Greek). ECG extracted features were used to train the different regression models in one-hour intervals. To enhance the best possible LVEF level estimations, hyperparameters tuning in nested loop approach was implemented (the outer loop divides the data into training and testing sets, while the inner loop further divides the training set into smaller sets for cross-validation). LVEF levels were best estimated using rational quadratic GPR and fine decision tree regression models with an average root mean square error (RMSE) of 3.83% and 3.42%, and correlation coefficients of 0.92 (p<0.01) and 0.91 (p<0.01), respectively. Furthermore, according to the experimental findings, the time periods of midnight-1 am, 8-9 am, and 10-11 pm demonstrated to be the lowest RMSE values between the actual and predicted LVEF levels. The findings could potentially lead to the development of an automated screening system for patients with coronary artery disease (CAD) by using the best measurement timings during their circadian cycles.

Project description:BackgroundThe prognostic impact and optimal treatment of left ventricular systolic dysfunction in patients with moderate aortic regurgitation (AR) remain unknown. We aimed to assess the prognostic value of left ventricular ejection fraction (LVEF) in patients with moderate AR and explore the potential benefits of aortic valve intervention (AVI).MethodsIn total, 1,211 consecutive patients with moderate AR (jet width, 25-64% of LV outflow tract; vena contracta, 0.3-0.6 cm; regurgitant volume, 30-59 mL/beat; regurgitant fraction, 30-49%; effective regurgitation orifice, 0.10-0.29 cm2) prospectively registered between April and June 2018 at 46 academic hospitals were included. The primary outcome was a composite of death or hospitalization for heart failure (HHF). The optimal LVEF threshold for predicting the primary outcome was determined through the penalized spline shape and maximally selected rank statistics.ResultsDuring the 2-year follow-up, 125 deaths or HHF occurred. In the penalized splines, the relative hazard of death or HHF monotonically increased with decreasing LVEF. In the multivariate analysis, LVEF ≤55% was identified as the best threshold for independently predicting death or HHF under medical treatment (adjusted hazard ratio [HR]: 2.18; 95% confidence interval [CI] 1.38-3.42; P = 0.001), with substantial incremental values (integrated discrimination improvement index = 0.018, P = 0.030; net reclassification improvement index = 0.225, P = 0.006; likelihood ratio test P < 0.001). Among patients with LVEF 35-55%, AVI within 6 months of diagnosis was associated with a reduced risk of death or HHF compared with medical treatment alone (adjusted HR: 0.15; 95% CI: 0.04-0.50; P = 0.002), whereas this benefit was markedly attenuated when LVEF was ≤35% (adjusted HR: 0.65; 95% CI: 0.21-1.97; P = 0.441, P-interaction = 0.010) or >55% (adjusted HR: 0.40; 95% CI: 0.14-1.15; P = 0.089, P-interaction = 0.723).ConclusionsLVEF is an independent and incremental prognostic factor in patients with moderate AR, with LVEF ≤55% being a robust marker of poor prognosis. Patients with LVEF 35-55% may benefit from early surgical correction of moderate AR. Further studies are warranted to validate our findings in a randomized setting.RegistrationChina Valvular Heart Disease Study (China-VHD study, NCT03484806); clinicaltrials.gov/ct2/show/NCT03484806.

Project description:ImportancePatients categorized as having heart failure (HF) with left ventricular ejection fraction (LVEF) in the midrange between 40% and 50% (HFmrEF) are known to be at increased risk of future events. Although patients can transition into the midrange through either improvement or deterioration in their LVEF, there is limited information available assessing the association of directional change in LVEF with future events. Understanding the association between change in LVEF and the clinical course of patients with HFmrEF would be of value in guiding management strategies.ObjectiveTo determine whether risk of clinical events experienced by patients with HFmrEF varies according to whether LVEF improved or deteriorated into the range of 40% to 50% from previous measurements.Design, setting, and participantsIn this retrospective cohort study, patients were identified from the electronic health records at the UC San Diego Health System who had an LVEF measured between 40% and 50% on transthoracic echocardiography (TTE) performed during the calendar year of 2015 and who also had at least 1 prior TTE for comparison. The clinical course of these patients was then followed from the time of the index TTE through December 2018. Data were analyzed from January to March 2019.Main outcomes and measuresThe composite of all-cause mortality and all-cause hospitalization, the composite of cardiovascular mortality and HF hospitalization, and each of the individual components.ResultsOf the 448 patients who were identified with HFmrEF, 278 (62.1%) were male, and the mean (SD) age was 67.4 (9.7) years. Left ventricular ejection fraction improved from less than 40% in 157 patients (35.0%), deteriorated from greater than 50% in 224 patients (50.0%), and remained between 40% and 50% over time in 67 patients (15.0%). Compared with patients whose LVEF improved from less than 40% to midrange levels, patients whose LVEF deteriorated from greater than 50% had higher risk of all-cause mortality and hospitalization (hazard ratio, 1.34; 95% CI, 1.10-1.82; P = .03) and of cardiovascular mortality and HF hospitalization (hazard ratio, 1.71; 95% CI, 1.08-2.50; P = .02), and these differences persisted after multivariable analysis. Outcomes did not differ significantly between patients whose LVEF improved and those in whom it remained stable.Conclusion and relevanceIn a cohort of patients with HFmrEF from a large academic medical center, the clinical course was strongly influenced by the directional change in LVEF from prior study. Patients whose LVEF deteriorated into midrange levels experienced a significantly higher risk of adverse clinical events than patients whose LVEF had improved. These results suggest that directional change in LVEF from prior measurements should be considered when devising management strategies for patients with HFmrEF.

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A moderate 500-m treadmill walk for estimating peak oxygen uptake in men with NYHA class I-II heart failure and reduced left ventricular ejection fraction.

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