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Peak Oxygen Consumption (peak + oxygen_consumption)

Distribution by Scientific Domains

Medical Sciences	88%

Selected Abstracts

Peak Oxygen Consumption and Heart Failure Prognosis,Does Race, Sex, or Fat Explain the Discrepancy?

CONGESTIVE HEART FAILURE, Issue 1 2009
Editor's note: The following commentary addresses issues raised in an article published in the previous issue.
No abstract is available for this article. [source]

Peak oxygen consumption and long-term all-cause mortality in nonsmall cell lung cancer,

CANCER, Issue 20 2010
Lee W. Jones PhD
Abstract BACKGROUND: Identifying strong markers of prognosis is critical to optimize treatment and survival outcomes in patients with nonsmall cell lung cancer (NSCLC). The authors investigated the prognostic significance of preoperative cardiorespiratory fitness (peak oxygen consumption [VO2peak]) among operable candidates with NSCLC. METHODS: By using a prospective design, 398 patients with potentially resectable NSCLC enrolled in Cancer and Leukemia Group B 9238 were recruited between 1993 and 1998. Participants performed a cardiopulmonary exercise test to assess VO2peak and were observed until death or June 2008. Cox proportional models were used to estimate the risk of all-cause mortality according to cardiorespiratory fitness category defined by VO2peak tertiles (<0.96 of 0.96-1.29/>1.29 L/min,1) with adjustment for age, sex, and performance status. RESULTS: Median follow-up was 30.8 months; 294 deaths were reported during this period. Compared with patients achieving a VO2peak <0.96 L/min,1, the adjusted hazard ratio (HR) for all-cause mortality was 0.64 (95% confidence interval [CI], 0.46-0.88) for a VO2peak of 0.96 to 1.29 L/min,1, and 0.56 (95% CI, 0.39-0.80) for a VO2peak of >1.29 L/min,1 (Ptrend = .0037). The corresponding HRs for resected patients were 0.66 (95% CI, 0.46-0.95) and 0.59 (95% CI, 0.40-0.89) relative to the lowest VO2peak category (Ptrend = .0247), respectively. For nonresected patients, the HRs were 0.78 (95% CI, 0.34-1.79) and 0.39 (95% CI, 0.16-0.94) relative to the lowest category (Ptrend = .0278). CONCLUSIONS: VO2peak is a strong independent predictor of survival in NSCLC that may complement traditional markers of prognosis to improve risk stratification and prognostication. Cancer 2010. © 2010 American Cancer Society. [source]

The Influence of Congenital Heart Disease on Psychological Conditions in Adolescents and Adults after Corrective Surgery

CONGENITAL HEART DISEASE, Issue 6 2006
Kambiz Norozi MD
ABSTRACT Objective., The present study was designed to examine psychological characteristics of adolescents and adults with operated congenital heart disease (ACHD). Particularly it was to be examined whether cardiological parameters may be associated with subjectively perceived impairments and measures of psychological distress. Patients., A total of 361 men (209) and women (152) between 14 and 45 years underwent medical checkups and an interview on psychological and sociological issues. Setting., The medical part consisted of a complete cardiological examination including the classification of residual symptoms according to the New York Heart Association (NYHA), and spiroergometry. The Brief Symptom Inventory was used for depicting current psychological and somatic symptoms. These were assessed on 9 subscales: somatization, obsession-compulsion, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation, and psychoticism. Results., The analyses revealed statistically significant associations between the degree of NYHA class and psychological symptoms. These findings could not be reproduced for physical fitness as measured by peak oxygen consumption. No gender differences emerged. Conclusions., Our results suggest that psychological measures of ACHD are not directly dependent on their physical fitness or on the severity of residual symptoms. Instead, patients' subjective appraisal of their disease severity and the conviction to what degree one can depend on the operated heart may be important determinants of psychological states. [source]

The Effect of Erythropoietin on Exercise Capacity, Left Ventricular Remodeling, Pressure-Volume Relationships, and Quality of Life in Older Patients With Anemia and Heart Failure With Preserved Ejection Fraction

CONGESTIVE HEART FAILURE, Issue 3 2010
Rose S. Cohen MD
A prospective, open-label, 3-month study was conducted to evaluate the feasibility and short-term clinical effect of subcutaneous erythropoietin injections in patients with anemia and heart failure with preserved ejection fraction (ejection fraction, 55%±2%). Using a dose-adjusted algorithm to effect a rate of rise in hemoglobin not to exceed 0.4 g/dL,/wk, hemoglobin (10.8±0.3 to 12.2±0.3 g/dL) and red blood cell volume (1187±55 to 1333±38 mL) increased with an average weekly dose of 3926 units. Functional measures increased from baseline (6-minute walk test [289±24 to 331±22 m], exercise time [432±62 to 571±51 s], and peak oxygen consumption [8.2±0.7 to 9.4±0.9 mL/kg/min], all P<.05). End-diastolic volume declined significantly (8% volumetric decrease, 108±3 to 100±3 mL, P =.03), but there were no significant changes in left ventricular mass or estimated left ventricular end-diastolic pressure. Pressure-volume analysis demonstrated a reduction in ventricular capacitance at an end-diastolic pressure of 30 mm Hg without significant changes in contractile state. Congest Heart Fail. 2010;16:96,103. © 2009 Wiley Periodicals, Inc. [source]

Short-Term Effects of Right Ventricular Pacing on Cardiorespiratory Function in Patients With a Biventricular Pacemaker

CONGESTIVE HEART FAILURE, Issue 6 2008
Stefan Toggweiler MD
The intention of this study was to evaluate the short-term effect of right ventricular (RV) pacing on cardiorespiratory function in patients with a biventricular pacemaker. A group of 26 patients with a biventricular pacemaker was enrolled in this cross-over, single-blind study. All patients underwent spiroergometry and electrocardiography in RV and biventricular pacing mode. Peak work capacity (102±32 W and 107±34 W for RV and biventricular pacing mode, respectively; P<.01) and peak oxygen consumption (21.4±6.7 mL/min/kg and 22.6±7.0 mL/min/kg for RV and biventricular pacing mode, respectively; P<.01) were significantly lower in the RV pacing mode. Heart rate at rest was significantly higher with active RV pacing. Short-term RV pacing in patients with a biventricular pacemaker resulted in a higher heart rate at rest, a lower peak work capacity, and a lower peak oxygen consumption compared with that in the biventricular pacing mode. [source]

Ten-Year Echo/Doppler Determination of the Benefits of Aerobic Exercise after the Age of 65 Years

ECHOCARDIOGRAPHY, Issue 1 2010
Alexander J. Muster M.D.
As the human lifespan becomes progressively extended, potential health-related effects of intense aerobic exercise after age 65 need evaluation. This study evaluates the cardiovascular (CV), pulmonary, and metabolic effects of competitive distance running on age-related deterioration in men between 69 (±3) and 77 (±2) years (mean ± SD). Twelve elderly competitive distance runners (ER) underwent oxygen consumption and echo/Doppler treadmill stress testing (Balke protocol) for up to 10 years. Twelve age-matched sedentary controls (SC) with no history of CV disease were similarly tested and the results compared for the initial three series of the study. CV data clearly separated the ER from SC. At entry, resting and maximal heart rate, systolic/diastolic blood pressure, peak oxygen consumption (VO2max), and E/A ratio of mitral inflow were better in the ER (P < 0.05 vs. SC). With aging, ER had a less deterioration of multiple health parameters. Exceptions were VO2max and left ventricular diastolic function (E/A, AFF, IVRT) that decreased (P < 0.05, Year 10 vs. Year 1). Health advantages of high-level aerobic exercise were demonstrated in the ER when compared to SC. Importantly, data collected in ER over 10 years confirm the benefit of intensive exercise for slowing several negative effects of aging. However, the normative drop of exercise capacity in the seventh and eighth decades reduces the potential athleticism plays in prevention of CV events. (Echocardiography 2010;27:5-10) [source]

Maximum Daily 6 Minutes of Activity: An Index of Functional Capacity Derived from Actigraphy and Its Application to Older Adults with Heart Failure

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 5 2010
Jason Howell BA
OBJECTIVES: To compare the correlation between the maximum 6 minutes of daily activity (M6min) and standard measures of functional capacity in older adults with heart failure (HF) with that in younger subjects and its prognostic utility. DESIGN: Prospective, cohort study. SETTING: Tertiary care, academic HF center. PARTICIPANTS: Sixty, ambulatory, adults, New York Heart Association (NYHA) Class I to III, stratified into young (50.9 ± 9.4) and older cohorts (76.8 ± 8.0). MEASUREMENTS: Correlation between M6min and measures of functional capacity (6-minute walk test; 6MWT) and peak oxygen consumption (VO2) according to cardiopulmonary exercise testing in a subset of subjects. Survival analysis was employed to evaluate the association between M6min and adverse events. RESULTS: Adherence to actigraphy was high (90%) and did not differ according to age. The correlation between M6min and 6MWT was higher in subjects aged 65 and older than in those younger than 65 (correlation coefficient (r=0.702, P<.001 vs r=0.490, P=.002). M6min was also significantly associated with peak VO2 (r=0.612, P=.006). During the study, 26 events occurred (2 deaths, 10 hospitalizations, 8 emergency department visits, and 6 intercurrent illnesses). The M6min was significantly associated with subsequent events (hazard ratio=2.728, 95% confidence interval=1.10,6.77, P=.03), independent of age, sex, ejection fraction, NYHA class, brain natriuretic peptide, and 6MWT. CONCLUSION: The high adherence to actigraphy and association with standard measures of functional capacity and independent association with subsequent morbid events suggest that it may be useful for monitoring older adults with HF. [source]

Estimating Cardiorespiratory Fitness in Well-Functioning Older Adults: Treadmill Validation of the Long Distance Corridor Walk

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 1 2006
Eleanor M. Simonsick PhD
Objectives: To determine criterion validity of the 400-m walk component of the Long Distance Corridor Walk (LDCW) and develop equations for estimating peak oxygen consumption (VO2) from 400-m time and factors intrinsic to test performance (e.g., heart rate (HR) and systolic blood pressure (SBP) response) in older adults. Design: Cross-sectional validation study. Setting: Gerontology Research Center, National Institute on Aging, Baltimore, Maryland. Participants: Healthy volunteers (56 men and 46 women) aged 60 to 91 participating in the Baltimore Longitudinal Study of Aging between August 1999 and July 2000. Measurements: The LDCW, consisting of a 2-minute walk followed immediately by a 400-m walk "done as quickly as possible" over a 20-m course was administered the day after maximal treadmill testing. HR and SBP were measured before testing and at the end of the 400-m walk. Weight, height, activity level, perceived effort, and stride length were also acquired. Results: Peak VO2 ranged from 12.2 to 31.1 mL oxygen/kg per minute, and 400-m time ranged from 2 minutes 52 seconds to 6 minutes 18 seconds. Correlation between 400-m time and peak VO2 was ,0.79. The estimating equation from linear regression included 400-m time (partial coefficient of determination (R2)=0.625), long versus short stride (partial R2=0.090), ending SBP (partial R2=0.019), and a correction factor for fast 400-m time (<240 seconds; partial R2=0.020) and explained 75.5% of the variance in peak VO2 (correlation coefficient=0.87). Conclusion: A 400-m walk performed as part of the LDCW provides a valid estimate of peak VO2 in older adults. Incorporating low-cost, safe assessments of fitness in clinical and research settings can identify early evidence of physical decline and individuals who may benefit from therapeutic interventions. [source]

Utilization of Defibrillators and Resynchronization Therapy at the Time of Evaluation at a Heart Failure and Cardiac Transplantation Center

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2010
DANIEL B. SIMS M.D.
Background: Internal cardioverter defibrillators (ICDs) and cardiac resynchronization therapy (CRT) reduce mortality, but are underutilized in routine clinical practice. The use of these devices in patients at the time of an initial evaluation at an advanced heart failure and cardiac transplantation center is unknown. Methods: We retrospectively analyzed consecutive patients who were enrolled in a database examining parameters of cardiopulmonary exercise testing in chronic heart failure (CHF) patients at the time of an initial outpatient evaluation at a tertiary care center. Rates of ICD and CRT use in eligible patients were determined. Results: Two hundred two patients had an average age of 54 ± 13 years and an average peak oxygen consumption (pVO2) of 12.5 ± 4.5 mL/kg/min. Of 97 patients eligible for an ICD only, 57% had an ICD at the time of evaluation. Sixty-four percent of ICD-eligible male patients had an ICD compared to 36% of ICD-eligible female patients (P = 0.015). Of 105 patients meeting criteria for CRT, 54% had a CRT device. There was no difference between CRT use in eligible male and female patients. Conclusions: ICDs and CRT are underutilized in patients with severe CHF at the time of evaluation at a tertiary care center despite young age, objective functional limitation, and active consideration for advanced CHF therapies. Female patients have lower rates of ICD use than male patients. (PACE 2010; 988,993) [source]

Impact of Right Ventricular Pacing Sites on Exercise Capacity during Ventricular Rate Regularization in Patients with Permanent Atrial Fibrillation

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2009
HUNG-FAT TSE M.D., Ph.D.
Background:The deleterious effects of right ventricular apical (RVA) pacing may offset the potential benefit of ventricular rate (VR) regularization and rate adaptation during an exercise in patient's atrial fibrillation (AF). Methods:We studied 30 patients with permanent AF and symptomatic bradycardia who receive pacemaker implantation with RVA (n = 15) or right ventricular septal (RVS, n = 15) pacing. All the patients underwent an acute cardiopulmonary exercise testing using VVI-mode (VVI-OFF) and VVI-mode with VR regularization (VRR) algorithm on (VVI-ON). Results:There were no significant differences in the baseline characteristics between the two groups, except pacing QRS duration was significantly shorter during RVS pacing than RVA pacing (138.9 ± 5 vs 158.4 ± 6.1 ms, P = 0.035). Overall, VVI-ON mode increased the peak exercise VR, exercise time, metabolic equivalents (METs), and peak oxygen consumption (VO2max), and decreased the VR variability compared with VVI-OFF mode during exercise (P < 0.05), suggesting that VRR pacing improved exercise capacity during exercise. However, further analysis on the impact of VRR pacing with different pacing sites revealed that only patients with RVS pacing but not patients with RVA pacing had significant increased exercise time, METs, and VO2max during VVI-ON compared with VVI-OFF, despite similar changes in peaked exercise VR and VR variability. Conclusion:In patients with permanent AF, VRR pacing at RVS, but not at RVA, improved exercise capacity during exercise. [source]

The Effects of Rate-Adaptive Atrial Pacing Versus Ventricular Backup Pacing on Exercise Capacity in Patients with Left Ventricular Dysfunction

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2009
M.S.C.E., ROD PASSMAN M.D.
Background: Atrial rate-adaptive pacing may improve cardiopulmonary reserve in patients with left ventricular dysfunction. Methods: A randomized, blinded, single-crossover design enrolled dual-chamber implantable defibrillator recipients without pacing indications and an ejection fraction ,40% to undergo cardiopulmonary exercise treadmill stress testing in both atrial rate-adaptive pacing (AAIR) and ventricular demand pacing (VVI) pacing modes. The primary endpoint was change in peak oxygen consumption (VO2). Secondary endpoints were changes in anaerobic threshold, perceived exertion, exercise duration, and peak blood pressure. Results: Ten patients, nine males, eight with New York Heart Association class I, mean ejection fraction 24 ± 7%, were analyzed. Baseline VO2 was 3.6 ± 0.5 mL/kg/min. Heart rate at peak exercise was significantly higher during AAIR versus VVI pacing (142 ± 18 vs 130 ± 23 bpm; P = 0.05). However, there was no difference in peak VO2 (AAIR 23.7 ± 6.1 vs VVI 23.8 ± 6.3 mL/kg/min; P = 0.8), anaerobic threshold (AAIR 1.3 ± 0.3 vs VVI 1.2 ± 0.2 L/min; P = 0.11), rate of perceived exertion (AAIR 7.3 ± 1.5 vs VVI 7.8 ± 1.2; P = 0.46), exercise duration (AAIR 15 minutes, 46 seconds ± 2 minutes, 54 seconds vs VVI 16 minutes, 3 seconds ± 2 minutes, 48 seconds; P = 0.38), or peak systolic blood pressure (AAIR 155 ± 22 vs VVI 153 ± 21; P = 0.61) between the two pacing modes. Conclusion: In this study, AAIR pacing did not improve peak VO2, anaerobic threshold, rate of perceived exertion, or exercise duration compared to VVI backup pacing in patients with left ventricular dysfunction and no pacing indications. [source]

Secular trend in peak oxygen consumption among United States youth in the 20th century

AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 6 2002
Joey C. Eisenmann
The purpose of this study was to examine secular change in peak oxygen consumption (Vo2) in U.S. boys and girls using available data from the 20th century. Studies were primarily identified from review articles and a Medline search. To be included in the analysis, studies must have included direct measurement of peak Vo2 on healthy (free from overt disease) United States children and youth from the general population separated by sex. Data (mean values) were divided by decade and separated into three age groups: 6,12, 13,15, and 16,18 years for boys, and 6,11, 12,14, and 15,18 years for girls. Peak Vo2 values were expressed as related to bipedal locomotion; therefore, cycle ergometry values were corrected by a factor of 1.075. Mean values were fit by least squares, goodness-of-fit regression lines. Results indicate that absolute (L·min,1) and relative (ml·kg,1·min,1) peak Vo2 have remained relatively stable among boys and young girls. In adolescent girls, particularly those 15 years of age and older, peak Vo2 has decreased by approximately 20% over the past few decades. The available data indicate that aerobic fitness has not decreased in United States youth except in adolescent girls over the past few decades. Am. J. Hum. Biol. 14:699,706, 2002. © 2002 Wiley-Liss, Inc. [source]

Cardiopulmonary exercise testing as a risk assessment method in non cardio-pulmonary surgery: a systematic review

ANAESTHESIA, Issue 8 2009
T. B. Smith
Summary This study reviews the predictive value of maximum oxygen consumption () and anaerobic threshold, obtained through cardiopulmonary exercise testing, in calculating peri-operative morbidity and mortality in non-cardiopulmonary thoraco-abdominal surgery. A literature review provided nine studies that investigated either one or both of these two variables across a wide range of surgical procedures. Six of the seven studies that reported sufficiently detailed results on peak oxygen consumption and four of the six studies that reported sufficiently detailed results on anaerobic threshold found them to be significant predictors. We conclude that peak oxygen consumption and possibly anaerobic threshold are valid predictors of peri-operative morbidity and mortality in non-cardiopulmonary thoraco-abdominal surgery. These indicators could potentially provide a means of allocating increased care to high-risk patients. [source]

Peak oxygen consumption and long-term all-cause mortality in nonsmall cell lung cancer,

Relationship between arterial baroreflex sensitivity and exercise capacity in patients with acute myocardial infarction

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 1 2010
Fumio Yuasa
Summary To investigate the relationship between arterial baroreflex sensitivity (BRS) and exercise capacity, we examined arterial BRS and its relation to exercise capacity during upright bicycle exercise in 40 uncomplicated patients with acute myocardial infarction. Arterial BRS was measured 3 weeks (20 ± 5 days) after acute myocardial infarction and assessed by calculating the regression line relating phenylephrine-induced increases in systolic blood pressure to the attendant changes in the R,R interval. All patients underwent graded symptom-limited bicycle exercise with direct measurements of hemodynamic and metabolic measurements. In all patients, the average arterial BRS was 5·6 ± 2·6 ms mmHg,1. There were no significant correlations between arterial BRS and hemodynamic measurements at rest. However, arterial BRS was negatively related to systemic vascular resistance at peak exercise (r = ,0·60, P = 0·0001) and percent change increase in systemic vascular resistance from rest to peak exercise (r = ,0·45, P = 0·003), whereas arterial BRS was positively related to cardiac output (r = ,0·48, P = 0·002) and stroke volume at peak exercise (r = 0·42, P = 0·007), and percent change increase in cardiac output (r = ,0·55, P = 0·0002) and stroke volume from rest to peak exercise (r = 0·41, P = 0·008). Furthermore, arterial BRS had modest but significant correlations with peak oxygen consumption (r = ,0·48, P = 0·002) and exercise duration (r = 0·35, P = 0·029), indicating that patients with better arterial BRS have better exercise capacity in patients with acute myocardial infarction. These results suggest that arterial BRS was linked to central and peripheral hemodynamic responses to exercise and hence, contributed to exercise capacity after acute myocardial infraction. [source]