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Zhong X, Tang J, Jiang R, Yuan P, Zhao Q, Gong S, Liu J, Wang L. The predictive value of minute ventilation versus carbon dioxide production in pulmonary hypertension associated with left heart disease. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:351. [PMID: 33708978 PMCID: PMC7944330 DOI: 10.21037/atm-21-366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Background The aim of the present study was to investigate the role of key cardiopulmonary exercise testing (CPET) parameters in the identification of pre-capillary components in patients with pulmonary hypertension associated with left heart disease (PH-LHD), and to evaluate their correlations with hemodynamic parameters. Methods Ninety patients with PH-LHD underwent right-heart catheterization, echocardiography, and CPET. The differences in related indexes between a combined post- and pre-capillary PH (Cpc-PH) group (n=47) and an isolated post-capillary PH (Ipc-PH) group (n=43) were compared. Correlation analysis was performed. Logistic regression and receiver operator characteristic (ROC) analyses were performed to assess the ability of CPET variables to distinguish patients with Cpc-PH from those with Ipc-PH. Results The hemodynamics, hyperventilation and right ventricular function of Cpc-pH group were worse than those of Ipc-pH group. The parameters related to minute ventilation versus carbon dioxide production (VE/VCO2) played a significant role in the differentiation of Cpc-PH and Ipc-PH, and had a moderate positive correlation with pulmonary vascular resistance (PVR). Univariate and multivariate logistic analyses showed that lowest percentage of VE/VCO2 in predicted value (VE/VCO2%pred) was the single best predictor of Cpc-PH, and the area under ROC curve also confirmed that lowest VE/VCO2%pred (≥137%) could serve as a novel diagnostic marker for Cpc-PH. On the basis of this lowest VE/VCO2%pred threshold, patients were divided into two groups. Most hemodynamic parameters were worse in patients with a lowest VE/VCO2%pred ≥137%. Conclusions VE/VCO2-related parameters are powerful prognosticators for the presence of pre-capillary components in patients with PH-LHD, especially lowest VE/VCO2%pred.
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Affiliation(s)
- Xiujun Zhong
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Respiratory Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jie Tang
- Department of Respiratory Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Rong Jiang
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ping Yuan
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Qinhua Zhao
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Sugang Gong
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jinming Liu
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Lan Wang
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
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Fermoyle CC, Stewart GM, Borlaug BA, Johnson BD. Pulmonary Vascular Pressures and Gas Exchange Response to Exercise in Heart Failure With Preserved Ejection Fraction. J Card Fail 2020; 26:1011-1015. [PMID: 32750488 DOI: 10.1016/j.cardfail.2020.07.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 07/13/2020] [Accepted: 07/20/2020] [Indexed: 11/15/2022]
Abstract
Elevated left ventricular filling pressure (measured as mean pulmonary capillary wedge pressure) at rest or with exercise is diagnostic of heart failure with preserved ejection fraction. However, the capacity of the right ventricle to compensate for a high mean pulmonary capillary wedge pressure and thus maintain an appropriate transpulmonary gradient (TPG) and perfusion of the pulmonary capillaries is likely an important contributor to gas exchange efficiency and exercise capacity. Therefore, this study aimed to determine whether a higher TPG at peak exercise is associated with superior exercise capacity and gas exchange. Gas exchange data from dyspneic patients referred for exercise right heart catheterization were retrospectively analyzed and patients were split into two groups based on TPG. Patients with a higher TPG at peak exercise had a higher peak VO2 (1025 ± 227 vs 823 ± 276, P = .038), end-tidal partial pressure of carbon dioxide (42.2 ± 7.9 vs 38.0 ± 4.7, P = .044), and gas exchange estimates of pulmonary vascular capacitance (408 ± 90 vs 268 ± 108, P = .001). A higher TPG at peak exercise correlated with a higher peak oxygen uptake, O2 pulse, and stroke volume (R = 0.42, 0.44 and 0.42, respectively, all P < 0.05). These findings indicate that a greater TPG with exercise might be important for improving exercise capacity in heart failure with preserved ejection fraction.
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Affiliation(s)
- Caitlin C Fermoyle
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Glenn M Stewart
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Barry A Borlaug
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Bruce D Johnson
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
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3
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Taylor BJ, Shapiro BP, Johnson BD. Exercise intolerance in heart failure: The important role of pulmonary hypertension. Exp Physiol 2020; 105:1997-2003. [PMID: 32092200 DOI: 10.1113/ep088105] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 02/20/2020] [Indexed: 12/21/2022]
Abstract
NEW FINDINGS What is the topic of this review? This review concerns the negative impact of pulmonary hypertension (PH) on the pulmonary haemodynamic and gas exchange responses to exercise, considering the mechanisms by which PH plays a role in exercise intolerance in heart failure (HF) patients. What advances does it highlight? The hallmark limited pulmonary vascular 'reserve' and impaired pulmonary gas exchange responses to exercise in HF are worsened by the development of PH; these are key determinants of exercise intolerance. Even HF patients who present with 'normal' pulmonary vascular function experience exercise-induced PH, which plays a role in exercise intolerance. ABSTRACT Patients with heart failure universally complain of exertional intolerance, but the underlying cause(s) of this intolerance may differ between patients with different disease phenotypes. Exercise introduces an impressive stress to the lungs, where elevations in venous return and cardiac output engender substantial increases in pulmonary blood volume and flow. Relative to healthy individuals, the pulmonary vascular reserve to accept this increase in pulmonary perfusion is compromised in heart failure, with a growing body of evidence suggesting that the development of pulmonary hypertension (PH), and in particular a precapillary component of PH, worsens the pulmonary haemodynamic response to exercise in these patients. Characterized by an exaggerated increase in pulmonary arterial pressure and an elevation in pulmonary vascular resistance, this dysfunctional pulmonary haemodynamic response plays a role in exercise intolerance, probably through an impairment of right ventricular function, underperfusion of the pulmonary circulation and a subsequent reduction in systemic blood flow and oxygen delivery. The hallmark abnormalities in ventilatory and pulmonary gas exchange that accompany heart failure, including a greater ventilatory equivalent for carbon dioxide, are also worsened by the development of PH. This raises the possibility that measures of exercise pulmonary gas exchange might help to 'describe' underlying PH in heart failure; however, several fundamental issues and questions need to be addressed before such gas exchange measures could truly be considered efficacious measures used to differentiate the type of PH and track the severity of PH in heart failure. exercise intolerance, heart failure, pulmonary gas exchange, pulmonary haemodynamics, pulmonary hypertension.
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Affiliation(s)
- Bryan J Taylor
- School of Biomedical Sciences, University of Leeds, Leeds, UK.,Department of Cardiovascular Diseases, Mayo Clinic, Jacksonville, FL, USA
| | - Brian P Shapiro
- Department of Cardiovascular Diseases, Mayo Clinic, Jacksonville, FL, USA
| | - Bruce D Johnson
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
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4
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Cross TJ, Kim CH, Johnson BD, Lalande S. The interactions between respiratory and cardiovascular systems in systolic heart failure. J Appl Physiol (1985) 2019; 128:214-224. [PMID: 31774354 DOI: 10.1152/japplphysiol.00113.2019] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Heart failure (HF) is a complex and multifaceted disease. The disease affects multiple organ systems, including the respiratory system. This review provides three unique examples illustrating how the cardiovascular and respiratory systems interrelate because of the pathology of HF. Specifically, these examples outline the impact of HF pathophysiology on 1) respiratory mechanics and the mechanical "cost" of breathing; 2) mechanical interactions of the heart and lungs; and on 3) abnormalities of pulmonary gas exchange during exercise, and how this may be applied to treatment. The goal of this review is to, therefore, raise the awareness that HF, though primarily a disease of the heart, is accompanied by marked pathology of the respiratory system.
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Affiliation(s)
- Troy James Cross
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester Minnesota
| | - Chul-Ho Kim
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester Minnesota
| | - Bruce D Johnson
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester Minnesota
| | - Sophie Lalande
- Department of Kinesiology and Heath Education, University of Texas at Austin, Austin, Texas
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5
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Biological variation of resting measures of ventilation and gas exchange in a large healthy cohort. Eur J Appl Physiol 2019; 119:2033-2040. [DOI: 10.1007/s00421-019-04190-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/11/2019] [Indexed: 10/26/2022]
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6
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Van Iterson EH, Smith JR, Olson TP. Exercise on-transition uncoupling of ventilatory, gas exchange and cardiac hemodynamic kinetics accompany pulmonary oxygen stores depletion to impact exercise intolerance in human heart failure. Acta Physiol (Oxf) 2018; 223:e13063. [PMID: 29575588 DOI: 10.1111/apha.13063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 03/04/2018] [Accepted: 03/08/2018] [Indexed: 12/16/2022]
Abstract
AIM In contrast to knowledge that heart failure (HF) patients demonstrate peak exercise uncoupling across ventilation, gas exchange and cardiac haemodynamics, whether this dyssynchrony follows that at the exercise on-transition is unclear. This study tested whether exercise on-transition temporal lag for ventilation relative to gas exchange and oxygen pulse (O2 pulse) couples with effects from abnormal pulmonary gaseous oxygen store (O2store ) contributions to V˙O2 to interdependently precipitate persistently elevated ventilatory demand and low oxidative metabolic capacity in HF. METHODS Beat-to-beat HR and breath-to-breath ventilation and gas exchange were continuously acquired in HF (N = 9, ejection fraction = 30 ± 9%) and matched controls (N = 10) during square-wave ergometry at 60% V˙O2peak (46 ± 14 vs 125 ± 54-W, P < .001). Temporal responses across V˙E , V˙O2 and O2 pulse were assessed for the exercise on-transition using single exponential model Phase II on-kinetic time constants (τ = time to reach 63% steady-state rise). Breath-to-breath gas fractions and respiratory flows were used to determine O2stores . RESULTS HF vs controls: τ for V˙E (137 ± 93 vs 74 ± 40-seconds, P = .03), V˙O2 (60 ± 40 vs 23 ± 5-seconds, P = .03) and O2 pulse (28 ± 18 vs 23 ± 15-seconds, P = .59). Within HF, τ for V˙E differed from O2 pulse (P < .02), but not V˙O2 . Exercise V˙E rise (workload indexed) differed in HF vs controls (545 ± 139 vs 309 ± 88-mL min-1 W-1 , P < .001). Exercise on-transition O2store depletion in HF exceeded controls, generally persisting to end-exercise. CONCLUSION These data suggest HF demonstrated exercise on-transition O2store depletion (high O2store contribution to V˙O2 ) coupled with dyssynchronous V˙E , V˙O2 and O2 pulse kinetics-not attributable to prolonged cardiac haemodynamics. Persistent high ventilatory demand and low oxidative metabolic capacity in HF may be precipitated by physiological uncoupling occurring within the exercise on-transition.
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Affiliation(s)
- E. H. Van Iterson
- Department of Cardiovascular Medicine; Mayo Clinic; Rochester MN USA
| | - J. R. Smith
- Department of Cardiovascular Medicine; Mayo Clinic; Rochester MN USA
| | - T. P. Olson
- Department of Cardiovascular Medicine; Mayo Clinic; Rochester MN USA
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7
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Van Iterson EH, Baker SE, Wheatley CM, Morgan WJ, Olson TP, Snyder EM. Exercise Stroke Volume in Adult Cystic Fibrosis: A Comparison of Acetylene Pulmonary Uptake and Oxygen Pulse. CLINICAL MEDICINE INSIGHTS-CIRCULATORY RESPIRATORY AND PULMONARY MEDICINE 2018; 12:1179548418790564. [PMID: 30083061 PMCID: PMC6073827 DOI: 10.1177/1179548418790564] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 06/28/2018] [Indexed: 12/19/2022]
Abstract
Cardiac hemodynamic assessment during cardiopulmonary exercise testing (CPET) is proposed to play an important role in the clinical evaluation of individuals with cystic fibrosis (CF). Cardiac catheterization is not practical for routine clinical CPET. Use of oxygen pulse (O2pulse) as a noninvasive estimate of stroke volume (SV) has not been validated in CF. This study tested the hypothesis that peak exercise O2pulse is a valid estimate of SV in CF. Measurements of SV via the acetylene rebreathe technique were acquired at baseline and peak exercise in 17 mild-to-moderate severity adult CF and 25 age-matched healthy adults. We calculated O2pulse=V.O2HR. Baseline relationships between SV and O2pulse were significant in CF (r = .80) and controls (r = .40), persisting to peak exercise in CF (r = .63) and controls (r = .73). The standard error of estimate for O2pulse-predicted SV with respect to measured SV was similar at baseline (14.1 vs 20.1 mL) and peak exercise (18.2 vs 13.9 mL) for CF and controls, respectively. These data suggest that peak exercise O2pulse is a valid estimate of SV in CF. The ability to noninvasively estimate SV via O2pulse during routine clinical CPET can be used to improve test interpretation and advance our understanding of the impact cardiac dysfunction has on exercise intolerance in CF.
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Affiliation(s)
| | - Sarah E Baker
- College of Pharmacy, The University of Arizona, Tucson, AZ, USA.,Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA
| | - Courtney M Wheatley
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA.,College of Pharmacy, The University of Arizona, Tucson, AZ, USA
| | - Wayne J Morgan
- Department of Pediatrics, The University of Arizona, Tucson, AZ, USA
| | - Thomas P Olson
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Eric M Snyder
- College of Pharmacy, The University of Arizona, Tucson, AZ, USA.,School of Kinesiology, University of Minnesota, Minneapolis, MN, USA
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Kim CH, Van Iterson EH, Hansen JE, MacCarter DJ, Johnson BD. Streamlining cardiopulmonary exercise testing for use as a screening and tracking tool in primary care. Pulm Circ 2018; 8:2045894018776489. [PMID: 29693481 PMCID: PMC5987906 DOI: 10.1177/2045894018776489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/20/2018] [Indexed: 11/16/2022] Open
Abstract
Cardiopulmonary exercise testing (CPET) using a spectrum of different approaches demonstrates usefulness for objectively assessing patient disease severity in clinical and research settings. Still, an absence of trained specialists and/or improper data interpretation techniques can pose major limitations to the effective use of CPET for the clinical classification of patients. This study aimed to test an automated disease likelihood scoring algorithm system based on cardiopulmonary responses during a simplified step-test protocol. For patients with heart failure (HF), pulmonary hypertension (PAH), obstructive lung disease (OLD), or restrictive lung disease (RLD), we compared patient scores stratified into one of four "silos" generated from our novel algorithm system against patient evaluations provided by expert clinicians. Patients with HF (n = 12), PAH (n = 9), OLD (n = 16), or RLD (n = 10) performed baseline pulmonary function testing followed by submaximal step-testing. Breath-by-breath measures of ventilation and gas exchange, in addition to oxygen saturation and heart rate were collected continuously throughout testing. The algorithm demonstrated close alignment with patient assessments provided by clinical specialists: HF (r = 0.89, P < 0.01); PAH (r = 0.88, P < 0.01); OLD (r = 0.70, P < 0.01); and RLD (r = 0.88, P < 0.01). Furthermore, the algorithm was capable of differentiating major disease from other disease pathologies. Thus, in a clinically relevant manner, these data suggest this simplified automated disease algorithm scoring system used during step-testing to identify the likelihood that patients have HF, PAH, OLD, or RLD closely correlates with patient assessments conducted by trained clinicians.
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Affiliation(s)
- Chul-Ho Kim
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
| | | | - James E. Hansen
- Respiratory and critical care physiology and medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Dean J. MacCarter
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
| | - Bruce D. Johnson
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
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9
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Influence of dietary nitrate supplementation on lung function and exercise gas exchange in COPD patients. Nitric Oxide 2018; 76:53-61. [PMID: 29549005 DOI: 10.1016/j.niox.2018.03.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 03/05/2018] [Accepted: 03/12/2018] [Indexed: 12/29/2022]
Abstract
BACKGROUND During exercise as pulmonary blood flow rises, pulmonary capillary blood volume increases and gas exchange surface area expands through distention and recruitment. We have previously demonstrated that pulmonary capillary recruitment is limited in COPD patients with poorer exercise tolerance. Hypoxia and endothelial dysfunction lead to pulmonary vascular dysregulation possibly in part related to nitric oxide related pathways. PURPOSE To determine if increasing dietary nitrate might influence lung surface area for gas exchange and subsequently impact exercise performance. METHODS Subjects had stable, medically treated COPD (n = 25), gave informed consent, filled out the St George Respiratory Questionnaire (SGRQ), had a baseline blood draw for Hgb, performed spirometry, and had exhaled nitric oxide (exNO) measured. Then they performed the intra-breath (IB) technique for lung diffusing capacity for carbon monoxide (DLCO) as well as pulmonary blood flow (Qc). Subsequently they completed a progressive semi-recumbent cycle ergometry test to exhaustion with measures of oxygen saturation (SpO2) and expired gases along with DLCO and Qc measured during the 1st work load only. Subjects were randomized to nitrate supplement group (beetroot juice) or placebo group (black currant juice) for 8 days and returned for repeat of the above protocol. RESULTS Exhaled nitric oxide levels rose >200% in the nitrate group (p < 0.05) with minimal change in placebo group. The SGRQ suggested a small fall in perceived symptom limitation in the nitrate group, but no measure of resting pulmonary function differed post nitrate supplementation. With exercise, there was no influence of nitrate supplementation on peak VO2 or other measures of respiratory gas exchange. There was a tendency for the exercise DLCO to increase slightly in the nitrate group with a trend towards a rise in the DLCO/Qc relationship (p = 0.08) but not in the placebo group. The only other significant finding was a fall in the exercise blood pressure in the nitrate group, but not placebo group (p < 0.05). CONCLUSION Despite evidence of a rise in exhaled nitric oxide levels with nitrate supplementation, there was minimal evidence for improvement in exercise performance or pulmonary gas exchange surface area in a stable medically treated COPD population.
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10
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Van Iterson EH, Olson TP, Borlaug BA, Johnson BD, Snyder EM. Comparisons of Noninvasive Methods Used to Assess Exercise Stroke Volume in Heart Failure with Preserved Ejection Fraction. Med Sci Sports Exerc 2018; 49:1758-1768. [PMID: 28471812 DOI: 10.1249/mss.0000000000001308] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
INTRODUCTION Cardiopulmonary exercise testing (CPET) plays an important role in properly phenotyping signs and symptoms of heart failure with preserved ejection fraction (HFpEF). The prognostic value of CPET is strengthened when accompanied by cardiac hemodynamic measurements. Although recognized as the "gold" standard, cardiac catheterization is impractical for routine CPET. Thus, advancing the scientific/methodologic understanding of noninvasive techniques for exercise cardiac hemodynamic assessment is clinically impactful in HFpEF. This study tested the concurrent validity of noninvasive acetylene gas (C2H2) uptake, echocardiography (ECHO), and oxygen pulse (O2pulse) for measuring/predicting exercise stroke volume (SV) in HFpEF. METHODS Eighteen white HFpEF and 18 age-/sex-matched healthy controls participated in upright CPET (ages, 69 ± 9 yr vs 63 ± 9 yr). At rest, 20 W, and peak exercise, SV was measured at steady-state via C2H2 rebreathe (SVACET) and ECHO (SVECHO), whereas O2pulse was derived (=V˙O2/HR). RESULTS Resting relationships between SVACET and SVECHO, SVECHO and O2pulse, or SVACET and O2pulse were significant in HFpEF (R = 0.30, 0.36, 0.67), but not controls (R = 0.07, 0.01, 0.09), respectively. Resting relationships persisted to 20 W in HFpEF (R = 0.70, 0.53, 0.70) and controls (R = 0.05, 0.07, 0.21), respectively. Peak exercise relationships were significant in HFpEF (R = 0.62, 0.24, 0.64), but only for SVACET versus O2pulse in controls (R = 0.07, 0.04, 0.33), respectively. Standardized standard error of estimate between techniques was strongest in HFpEF at 20 W: SVACET versus SVECHO = 0.57 ± 0.22; SVECHO versus O2pulse = 0.71 ± 0.28; SVACET versus O2pulse = 0.56 ± 0.22. CONCLUSIONS Constituting a clinically impactful step towards construct validation testing, these data suggest SVACET, SVECHO, and O2pulse demonstrate moderate-to-strong concurrent validity for measuring/predicting exercise SV in HFpEF.
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Affiliation(s)
- Erik H Van Iterson
- 1Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN; and 2Department of Kinesiology, University of Minnesota, Minneapolis, MN
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11
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Behnia M, Wheatley CM, Avolio A, Johnson BD. Alveolar-capillary reserve during exercise in patients with chronic obstructive pulmonary disease. Int J Chron Obstruct Pulmon Dis 2017; 12:3115-3122. [PMID: 29123389 PMCID: PMC5661445 DOI: 10.2147/copd.s142523] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background Factors limiting exercise in patients with COPD are complex. With evidence for accelerated pulmonary vascular aging, destruction of alveolar-capillary bed, and hypoxic pulmonary vasoconstriction, the ability to functionally expand surface area during exercise may become a primary limitation. Purpose To quantify measures of alveolar-capillary recruitment during exercise and the relationship to exercise capacity in a cohort of COPD patients. Methods Thirty-two subjects gave consent (53% male, with mean ± standard deviation age 66±9 years, smoking 35±29 pack-years, and Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification of 0-4: 2.3±0.8), filled out the St George's Respiratory Questionnaire (SGRQ) to measure quality of life, had a complete blood count drawn, and underwent spirometry. The intrabreath (IB) technique for lung diffusing capacity for carbon monoxide (IBDLCO) and pulmonary blood flow (IBQc, at rest) was also performed. Subsequently, they completed a cycle ergometry test to exhaustion with measures of oxygen saturation and expired gases. Results Baseline average measures were 44±21 for SGRQ score and 58±11 for FEV1/FVC. Peak oxygen consumption (VO2) was 11.4±3.1 mL/kg/min (49% predicted). The mean resting IBDLCO was 9.7±5.4 mL/min/mmHg and IBQc was 4.7±0.9 L/min. At the first workload, heart rate (HR) increased to 92±11 bpm, VO2 was 8.3±1.4 mL/kg/min, and IBDLCO and IBQc increased by 46% and 43%, respectively, compared to resting values (p,0.01). The IBDLCO/Qc ratio averaged 2.0±1.1 at rest and remained constant during exercise with marked variation across subjects (range: 0.8-4.8). Ventilatory efficiency plateaued at 37±5 during exercise, partial pressure of mix expired CO2/partial pressure of end tidal CO2 ratio ranged from 0.63 to 0.67, while a noninvasive index of pulmonary capacitance, O2 pulse × PetCO2 (GxCap) rose to 138%. The exercise IBDLCO/Qc ratio was related to O2 pulse (VO2/HR, r=0.58, p<0.01), and subjects with the highest exercise IBDLCO/Qc ratio or the greatest rise from rest had the highest peak VO2 values (r=0.65 and 0.51, respectively, p<0.05). Of the noninvasive gas exchange measures of pulmonary vascular function, GxCap was most closely associated with DLCO, DLCO/Qc, and VO2 peak. Conclusion COPD patients who can expand gas exchange surface area as assessed with DLCO during exercise relative to pulmonary blood flow have a more preserved exercise capacity.
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Affiliation(s)
- Mehrdad Behnia
- Division of Critical Care, Florida Hospital, Orlando, FL
| | | | - Alberto Avolio
- Australian School of Advanced Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Bruce D Johnson
- Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, AZ, USA
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12
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Kim CH, Hansen JE, MacCarter DJ, Johnson BD. Algorithm for Predicting Disease Likelihood From a Submaximal Exercise Test. Clin Med Insights Circ Respir Pulm Med 2017; 11:1179548417719248. [PMID: 28757799 PMCID: PMC5513526 DOI: 10.1177/1179548417719248] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 06/04/2017] [Indexed: 12/13/2022] Open
Abstract
We developed a simplified automated algorithm to interpret noninvasive gas exchange in healthy subjects and patients with heart failure (HF, n = 12), pulmonary arterial hypertension (PAH, n = 11), chronic obstructive lung disease (OLD, n = 16), and restrictive lung disease (RLD, n = 12). They underwent spirometry and thereafter an incremental 3-minute step test where heart rate and SpO2 respiratory gas exchange were obtained. A custom-developed algorithm for each disease pathology was used to interpret outcomes. Each algorithm for HF, PAH, OLD, and RLD was capable of differentiating disease groups (P < .05) as well as healthy cohorts (n = 19, P < .05). In addition, this algorithm identified referral pathology and coexisting disease. Our primary finding was that the ranking algorithm worked well to identify the primary referral pathology; however, coexisting disease in many of these pathologies in some cases equally contributed to the cardiorespiratory abnormalities. Automated algorithms will help guide decision making and simplify a traditionally complex and often time-consuming process.
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Affiliation(s)
- Chul-Ho Kim
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
| | - James E Hansen
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
| | - Dean J MacCarter
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
| | - Bruce D Johnson
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
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13
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Van Iterson EH, Snyder EM, Johnson BD, Olson TP. Influence of the Metaboreflex on Pulmonary Vascular Capacitance in Heart Failure. Med Sci Sports Exerc 2017; 48:353-62. [PMID: 26414317 DOI: 10.1249/mss.0000000000000775] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE An impaired metaboreflex is associated with abnormal ventilatory and peripheral vascular function in heart failure (HF), whereas its influence on cardiac function or pulmonary vascular pressure remains unclear. We aimed to assess whether metabolite-sensitive neural feedback (metaboreflex) from locomotor muscles via postexercise regional circulatory occlusion (RCO) attenuates pulmonary vascular capacitance (GXCAP) and/or circulatory power (CircP) in patients with HF. METHODS Eleven patients with HF (NYHA class, I/II; ages, 51 ± 15 yr; ejection fraction, 32% ± 9%) and 11 age- and gender-matched controls (ages, 43 ± 9 yr) completed three cycling sessions (4 min, 60% peak oxygen uptake (V˙O2)). Session 1 was a control trial including normal recovery (NR). Session 2 or 3 included bilateral upper thigh pressure tourniquets inflated suprasystolic at end of exercise (RCO) for 2-min recovery with or without inspired CO2 (RCO + CO2) (randomized). Mean arterial pressure, HR, and V˙O2 were continuously measured. Estimates of central hemodynamics; CircP = (V˙O2 × mean arterial pressure)/weight; oxygen pulse index (O2pulseI = (V˙O2/HR)/body surface area); and GXCAP = O2pulseI × end-tidal partial pressure CO2 were calculated. RESULTS At rest and end of exercise, CircP and GXCAP were lower in HF versus those in controls (P < 0.05), with no differences between transients (P > 0.05). At 2-min recovery, GXCAP was lower during RCO versus that during NR in both groups (72 ± 23 vs 98 ± 20 and 73 ± 34 vs 114 ± 35 mL·beat·mm Hg·m, respectively; P < 0.05), whereas CircP did not differ between transients (P > 0.05). Differences (% and Δ) between baseline and 2-min recovery among transients suggest that metaboreflex attenuates GXCAP in HF. Differences (% and Δ) between baseline and 2-min recovery among transients suggest that metaboreflex may attenuate CircP in controls. CONCLUSIONS The present observations suggest that locomotor muscle metaboreflex activation may influence CircP in controls but not in HF. However, metaboreflex activation may evoke decreases in GXCAP (increased pulmonary vascular pressures) in HF and controls.
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Affiliation(s)
- Erik H Van Iterson
- 1Department of Kinesiology, University of Minnesota, Minneapolis, MN; 2Cardiovascular Medicine Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; and 3Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN
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Snyder EM, Van Iterson EH, Olson TP. Clinical Classification of Heart Failure Patients Using Cardiac Function during Exercise. Exerc Sport Sci Rev 2016. [PMID: 26196869 DOI: 10.1249/jes.0000000000000061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An effective approach for determining the clinical classification of heart failure (HF) patients is to estimate cardiac hemodynamics during exercise. This approach is strengthened further when measurements including cardiac power are used to describe cardiac hemodynamics. We hypothesize that cardiac power quantifies the hemodynamic and pressure-generating capability of the heart, relating with exercise tolerance better than traditional measurements in HF.
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Affiliation(s)
- Eric M Snyder
- 1School of Kinesiology, University of Minnesota, Minneapolis, MN; 2Cardiovascular Medicine Division, University of Pennsylvania, Philadelphia, PA; and 3Division of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
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15
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Agarwal M, Waxman AB. Physiological Techniques and Pulmonary Hypertension - Left Heart Disease. Prog Cardiovasc Dis 2016; 59:30-41. [PMID: 27211586 DOI: 10.1016/j.pcad.2016.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 05/11/2016] [Indexed: 01/06/2023]
Abstract
Group 2 Pulmonary hypertension (PH) is associated with left heart disease (LHD;Group 2 PH) and is the most common form of PH. Group 2 PH represents an important subgroup of patients with LHD where the development of PH leads to a significant increase in morbidity and mortality. Early diagnosis may provide an opportunity to intervene and significantly delay progression. In addition to clinical suspicion, several approaches including hemodynamic assessment, exercise testing, and imaging techniques play an important role in better disease characterization and management. Here, we review the role of physiologic based hemodynamic and exercise assessments of Group 2 PH patients.
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Affiliation(s)
- Manyoo Agarwal
- Department of Internal Medicine, University of Tennessee Health Science Center, Memphis, TN, USA; Pulmonary and Critical Care Medicine, Center for Pulmonary Heart Disease, Brigham and Women's Hospital Heart and Vascular Center
| | - Aaron B Waxman
- Pulmonary and Critical Care Medicine, Center for Pulmonary Heart Disease, Brigham and Women's Hospital Heart and Vascular Center; Pulmonary and Critical Care Medicine, Cardiovascular Medicine, Pulmonary Vascular Disease Program, Center for Pulmonary-Heart Diseases, Brigham and Women's Hospital Heart and Vascular Center, Harvard Medical School.
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Kim CH, Jae SY, Johnson BD. Pulmonary Hypertension and Cardiopulmonary Exercise in Heart Failure. ACTA ACUST UNITED AC 2015; 1:143-51. [PMID: 26389080 PMCID: PMC4315347 DOI: 10.1159/000360964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In heart failure (HF), pulmonary hypertension (PH) is initially associated with a rise in the left ventricular filling pressure. PH is defined by pulmonary hemodynamic measurements including pulmonary capillary wedge pressure, mean pulmonary arterial pressure and pulmonary vascular resistance. Eventually, PH in HF may become more of a reactive process. Although the mechanism of the reactive PH development is not clearly understood, vascular dysfunction induced by remodeling, vasoactive substances and genetic variation appear to contribute significantly to this form of PH. Noninvasive cardiopulmonary exercise testing has been extensively utilized to assess disease severity in HF patients. It provides integrated information that is dependent on cardiopulmonary hemodynamics, lung mechanics, breathing pattern and strategy. In this review, we will discuss the mechanisms of PH development in HF and how noninvasive gas exchange measures obtained with submaximal exercise are influenced by PH in this population.
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Affiliation(s)
- Chul-Ho Kim
- Division of Cardiovascular Disease, Mayo Clinic, Rochester, Minn., USA
| | - Sae Young Jae
- The Health and Integrative Physiology Laboratory, University of Seoul, Seoul, Korea
| | - Bruce D Johnson
- Division of Cardiovascular Disease, Mayo Clinic, Rochester, Minn., USA
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Van Iterson EH, Snyder EM, Joyner MJ, Johnson BD, Olson TP. Intrathecal fentanyl blockade of afferent neural feedback from skeletal muscle during exercise in heart failure patients: Influence on circulatory power and pulmonary vascular capacitance. Int J Cardiol 2015; 201:384-93. [PMID: 26310984 DOI: 10.1016/j.ijcard.2015.08.101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 06/02/2015] [Accepted: 08/09/2015] [Indexed: 01/08/2023]
Abstract
BACKGROUND Secondary pulmonary hypertension is common in heart failure (HF) patients. We hypothesized that inhibition of feedback from locomotor muscle group III/IV neurons contributes to reduced pulmonary vascular pressures independent of changes in cardiac function during exercise in HF. METHODS 9 HF patients (ages, 60 ± 2; EF, 26.7 ± 1.9%; New York Heart Association classes, I-III) and 9 age/gender matched controls (ages, 63 ± 2) completed five-minutes of constant-load cycling (65% Workloadpeak) with intrathecal fentanyl or placebo on randomized separate days. Mean arterial pressure (MAP), heart rate (HR), end-tidal partial pressure of CO2 (PETCO2), and oxygen consumption (VO2) were measured at rest and exercise. Non-invasive surrogates for cardiac power (circulatory power, CircP=VO2 × MAP), stroke volume (oxygen pulse, O2pulse=VO2/HR), and pulmonary arterial pressure (GXCAP=O2pulse × PETCO2) were calculated. RESULTS At rest and end-exercise, differences between fentanyl versus placebo were not significant for CircP in HF or controls. Differences between fentanyl versus placebo for GXCAP were not significant at rest in HF or controls. At end-exercise, GXCAP was significantly higher with fentanyl versus placebo in HF (691 ± 59 versus 549 ± 38 mL/beat × mmHg), but not controls (536 ± 59 versus 474 ± 43 mL/beat × mmHg). Slopes (rest to end-exercise) for GXCAP were significantly higher with fentanyl versus placebo in HF (95.1 ± 9.8 versus 71.6 ± 6.0 mL/beat × mmHg), but not controls (74.3 ± 9.5 versus 60.8 ± 6.5 mL/beat × mmHg). CircP slopes did not differ between fentanyl versus placebo in HF or controls (p>0.05). CONCLUSION We conclude that feedback from locomotor muscle group III/IV neurons may evoke increases in pulmonary vascular pressures independent of changes in cardiac function during exercise in HF.
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Affiliation(s)
- Erik H Van Iterson
- Department of Kinesiology, University of Minnesota, Cooke Hall, 1900 University Ave. SE, Minneapolis, MN 55455, USA.
| | - Eric M Snyder
- Department of Kinesiology, University of Minnesota, Cooke Hall, 1900 University Ave. SE, Minneapolis, MN 55455, USA
| | - Michael J Joyner
- Division of Cardiovascular Diseases, Mayo Clinic, Gonda 5 South, 200 First Street, SW, Rochester, MN 55905, USA
| | - Bruce D Johnson
- Division of Cardiovascular Diseases, Mayo Clinic, Gonda 5 South, 200 First Street, SW, Rochester, MN 55905, USA
| | - Thomas P Olson
- Division of Cardiovascular Diseases, Mayo Clinic, Gonda 5 South, 200 First Street, SW, Rochester, MN 55905, USA
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Kim CH, Olson LJ, Shen WK, Cha YM, Johnson BD. Ventilatory gas exchange and early response to cardiac resynchronization therapy. J Heart Lung Transplant 2015; 34:1430-5. [PMID: 26163155 DOI: 10.1016/j.healun.2015.05.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 04/17/2015] [Accepted: 05/28/2015] [Indexed: 10/23/2022] Open
Abstract
BACKGROUND Cardiac resynchronization therapy (CRT) is an accepted intervention for chronic heart failure (HF), although approximately 30% of patients are non-responders. The purpose of this study was to determine whether exercise respiratory gas exchange obtained before CRT implantation predicts early response to CRT. METHODS Before CRT implantation, patients were assigned to either a mild-moderate group (Mod G, n = 33, age 67 ± 10 years) or a moderate-severe group (Sev G, n = 31, age 67 ± 10 years), based on abnormalities in exercise gas exchange. Severity of impaired gas exchange was based on a score from the measures of VE/VCO(2) slope, resting PETCO(2) and change of PETCO(2) from resting to peak. All measurements were performed before and 3 to 4 months after CRT implantation. RESULTS Although Mod G did not have improved gas exchange (p > 0.05), Sev G improved significantly (p < 0.05) post-CRT. In addition, Mod G did not show improved right ventricular systolic pressure (RSVP; pre vs post: 37 ± 14 vs 36 ± 11 mm Hg, p > 0.05), yet Sev G showed significantly improved RVSP, by 23% (50 ± 14 vs 42 ± 12 mm Hg, p < 0.05). Both groups had improved left ventricular ejection fraction (p < 0.05), New York Heart Association class (p < 0.05) and quality of life (p < 0.05), but no significant differences were observed between groups (p > 0.05). No significant changes were observed in brain natriuretic peptide in either group post-CRT. CONCLUSION Based on pre-CRT implantation ventilatory gas exchange, subjects with the most impaired values appeared to have more improvement post-CRT, possibly associated with a decrease in RVSP.
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Affiliation(s)
- Chul-Ho Kim
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
| | - Lyle J Olson
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Win K Shen
- Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona
| | - Yong-Mei Cha
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Bruce D Johnson
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
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Taylor BJ, Smetana MR, Frantz RP, Johnson BD. Submaximal Exercise Pulmonary Gas Exchange in Left Heart Disease Patients With Different Forms of Pulmonary Hypertension. J Card Fail 2015; 21:647-55. [PMID: 25887446 DOI: 10.1016/j.cardfail.2015.04.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 02/15/2015] [Accepted: 04/06/2015] [Indexed: 11/30/2022]
Abstract
BACKGROUND We determined whether pulmonary gas exchange indices during submaximal exercise are different in heart failure (HF) patients with combined post- and pre-capillary pulmonary hypertension (PPC-PH) versus HF patients with isolated post-capillary PH (IPC-PH) or no PH. METHODS AND RESULTS Pulmonary hemodynamics and pulmonary gas exchange were assessed during rest and submaximal exercise in 39 HF patients undergoing right heart catheterization. After hemodynamic evaluation, patients were classified as having no PH (n = 11), IPC-PH (n = 12), or PPC-PH (n = 16). At an equivalent oxygen consumption, end-tidal CO2 (PETCO2) and arterial oxygen saturation (SaO2) were greater in no-PH and IPC-PH versus PPC-PH patients (36.1 ± 3.2 vs. 31.7 ± 4.5 vs. 26.2 ± 4.7 mm Hg and 97 ± 2 vs. 96 ± 3 vs. 91 ± 1%, respectively). Conversely, dead-space ventilation (VD/VT) and the ventilatory equivalent for carbon dioxide (V˙(E)/V˙CO2 ratio) were lower in no-PH and IPC-PH versus PPC-PH patients (0.37 ± 0.05 vs. 0.38 ± 0.04 vs. 0.47 ± 0.03 and 38 ± 5 vs. 42 ± 8 vs. 51 ± 8, respectively). The exercise-induced change in V(D)/V(T), V˙(E)/V˙CO2 ratio, and PETCO2 correlated significantly with the change in mean pulmonary arterial pressure, diastolic pressure difference, and transpulmonary pressure gradient in PPC-PH patients only. CONCLUSIONS Noninvasive pulmonary gas exchange indices during submaximal exercise are different in HF patients with combined post- and pre-capillary PH compared with patients with isolated post-capillary PH or no PH.
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Affiliation(s)
- Bryan J Taylor
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota.
| | - Michael R Smetana
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota
| | - Robert P Frantz
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota
| | - Bruce D Johnson
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota
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Taylor BJ, Olson TP, Chul-Ho-Kim, Maccarter D, Johnson BD. Use of noninvasive gas exchange to track pulmonary vascular responses to exercise in heart failure. CLINICAL MEDICINE INSIGHTS-CIRCULATORY RESPIRATORY AND PULMONARY MEDICINE 2013; 7:53-60. [PMID: 24093002 PMCID: PMC3785385 DOI: 10.4137/ccrpm.s12178] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We determined whether a non-invasive gas exchange based estimate of pulmonary vascular (PV) capacitance [PVCAP = stroke volume (SV) × pulmonary arterial pressure (Ppa)] (GXCAP) tracked the PV response to exercise in heart-failure (HF) patients. Pulmonary wedge pressure (Ppw), Ppa, PV resistance (PVR), and gas exchange were measured simultaneously during cycle exercise in 42 HF patients undergoing right-heart catheterization. During exercise, PETCO2 and VE/VCO2 were related to each other (r = −0.93, P < 0.01) and similarly related to mean Ppa (mPpa) (r = −0.39 and 0.36; P < 0.05); PETCO2 was subsequently used as a metric of mPpa. Oxygen pulse (O2 pulse) tracked the SV response to exercise (r = 0.91, P < 0.01). Thus, GXCAP was calculated as O2 pulse × PETCO2. During exercise, invasively determined PVCAP and non-invasive GXCAP were related (r = 0.86, P < 0.01), and GXCAP correlated with mPpa and PVR (r = −0.46 and −0.54; P < 0.01). In conclusion, noninvasive gas exchange measures may represent a simple way to track the PV response to exercise in HF.
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Affiliation(s)
- Bryan J Taylor
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA
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