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Wright SP, Goodman JM, Sasson Z, Granton JT, Mak S. Left atrial reservoir pressure-volume relations during exercise in healthy older adults. J Appl Physiol (1985) 2024; 136:901-907. [PMID: 38420677 DOI: 10.1152/japplphysiol.00905.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 02/14/2024] [Accepted: 02/21/2024] [Indexed: 03/02/2024] Open
Abstract
The left atrium (LA) mediates cardiopulmonary interactions. During ventricular systole, the LA functions as a compliant reservoir that is coupled to the left ventricle (LV) and offloads volume from the pulmonary vasculature. We aimed to describe LA reservoir function using phasic relationships between pulmonary artery wedge pressure (PAWP) and LA volume events. We included healthy adults (7 M/6 F, 56 ± 8 yr) who were studied at rest and during semirecumbent cycle ergometry at a target of 100 beats/min heart rate. Right heart catheterization was performed to record the PAWP and two-dimensional (2-D) echocardiography was used to measure LA and LV volumes. We manually measured A-wave, x-trough, V-wave, and y-trough PAWP beat-by-beat, as well as minimal, maximal, and precontraction biplane LA volumes. Heart rate increased by 40 ± 7 beats/min with exercise; stroke volume and cardiac output also rose. Although all phasic PAWP measurements increased with exercise, the x-V pressure pulse during LA filling doubled from 4 ± 2 to 8 ± 4 mmHg (P = 0.001). LA minimal volume was unchanged but maximal volume increased from 39 ± 9 to 48 ± 9 mL (P < 0.001) with exercise, and so reservoir volume increased from 24 ± 5 to 32 ± 8 mL (P < 0.001). As such, calculated LA compliance decreased from 6.8 ± 3.4 to 4.8 ± 2.6 mL/mmHg (P = 0.029). The product of V-wave PAWP and LA maximal volume, a surrogate for LA wall stress, increased from 486 ± 193 to 953 ± 457 mmHg·mL (P < 0.001). In healthy older adults during submaximal exercise, the PAWP waveform shifts upward and its amplitude widens, LA filling increases, LA compliance decreases modestly, and LA wall stress may augment substantially.NEW & NOTEWORTHY We combined invasive estimates of left atrial pressure with noninvasive left atrial volume measurements made at rest and during exercise in healthy humans. Left atrial pressure and volume both increased with exercise, though the pressure increase was relatively greater, and calculated compliance decreased modestly while estimated peak wall stress nearly doubled. Our results demonstrate left atrial loading during exercise in healthy older adults and provide insight into how the left atrium mediates cardiopulmonary interactions.
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Affiliation(s)
- Stephen P Wright
- Centre for Heart, Lung and Vascular Health, University of British Columbia, Kelowna, British Columbia, Canada
- Division of Cardiology, Sinai Health System/University Health Network, Toronto, Ontario, Canada
| | - Jack M Goodman
- Division of Cardiology, Sinai Health System/University Health Network, Toronto, Ontario, Canada
- Department of Exercise Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Zion Sasson
- Division of Cardiology, Sinai Health System/University Health Network, Toronto, Ontario, Canada
| | - John T Granton
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Division of Respirology, Sinai Health System/University Health Network, Toronto, Ontario, Canada
| | - Susanna Mak
- Division of Cardiology, Sinai Health System/University Health Network, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
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Duke JW, Lovering AT. Respiratory and cardiopulmonary limitations to aerobic exercise capacity in adults born preterm. J Appl Physiol (1985) 2020; 129:718-724. [PMID: 32790592 DOI: 10.1152/japplphysiol.00419.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Adults born preterm, regardless of whether they develop bronchopulmonary dysplasia, have underdeveloped respiratory and cardiopulmonary systems. The resulting impaired respiratory and cardiopulmonary systems are inadequate for the challenges imposed by aerobic exercise, which is exacerbated by the presence of bronchopulmonary dysplasia. Thus the respiratory and cardiopulmonary systems of these preterm individuals may be the most influential contributors to the significantly lower aerobic exercise capacity compared with their term born counterparts. The precise underlying cause(s) of the lower aerobic exercise capacity in adults born preterm is not entirely known but could be a number of interrelated parameters including mechanical ventilatory constraints, impaired pulmonary gas exchange efficiency, and excessive cardiopulmonary pressures. Likewise, additional aspects, such as impaired cardiovascular function and altered muscle bioenergetics, may play additional roles in limiting aerobic exercise capacity. Whether or not all or some of these aspects are present in adults born preterm and precisely how they may contribute to the lower aerobic exercise capacity are only beginning to be systematically explored. The purpose of this mini-review is to outline what is currently known about the respiratory and cardiopulmonary limitations during exercise in this population and to identify key areas where additional knowledge will help to advance this area. Additionally, where possible, we highlight the similarities and differences between obstructive lung disease resulting from preterm birth and chronic obstructive pulmonary disease (COPD) as the physiology and pathophysiology of these two forms of obstructive lung disease may not be identical.
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Affiliation(s)
- Joseph W Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon
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Durand F, Gaston AF, Vicenzi M, Deboeck G, Subirats E, Faoro V. Noninvasive Pulmonary Hemodynamic Evaluation in Athletes With Exercise-Induced Hypoxemia. Chest 2020; 157:1568-1578. [PMID: 32081649 DOI: 10.1016/j.chest.2020.01.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 12/22/2019] [Accepted: 01/31/2020] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND Pulmonary capillary stress failure is potentially involved in exercise-induced hypoxemia (ie, a significant fall in hemoglobin oxygen saturation [Spo2]) during sea level exercise in endurance-trained athletes. It is unknown whether there are specific properties of pulmonary vascular function in athletes exhibiting oxygen desaturation. METHODS Ten endurance-trained athletes with exercise-induced hypoxemia (EIH), nine endurance-trained athletes with no exercise-induced hypoxemia (NEIH), and 10 untrained control subjects underwent an incremental exercise stress echocardiography coupled with lung diffusion capacity for carbon monoxide (Dlco) and lung diffusion capacity for nitric oxide (Dlno) testing. Functional adaptation of the pulmonary circulation was evaluated with measurements of mean pulmonary arterial pressure (mPAP), pulmonary capillary pressure, pulmonary vascular resistance (PVR), cardiac output (Qc), and pulmonary vascular distensibility (alpha) mathematically determined from the curvilinearity of the multi-point mPAP/Qc relation. RESULTS EIH athletes exhibited a lower exercise-induced PVR decrease compared with the untrained and NEIH groups (P < .001). EIH athletes showed higher maximal mPAP compared with NEIH athletes (45.4 ± 0.9 mm Hg vs 41.6 ± 0.9 mm Hg, respectively; P = .003); there was no difference between the NEIH and untrained subjects. Alpha was lower in the EIH group compared with the NEIH group (P < .05). Maximal mPAP, Pcap, and alpha were correlated with the fall of Spo2 during exercise (P < .01, P < .01, and P < .05). Dlno and Dlco increased with exercise in all groups, with no differences between groups. Dlno/Qc was correlated to the exercise-induced Spo2 changes (P < .05). CONCLUSIONS EIH athletes exhibit higher maximal pulmonary vascular pressures, lower vascular distensibility, or exercise-induced changes in PVR compared with NEIH subjects, in keeping with pulmonary capillary stress failure or intrapulmonary shunting hypotheses.
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Affiliation(s)
- Fabienne Durand
- Laboratoire Européen Performance, Santé Altitude, EA4604-Université de Perpignan Via Domitia, Département STAPS, Font-Romeu, France; Catedra de medicina de muntanya I del medi natural I de simulacio clinica, Universitat de Girona, Girona, Spain.
| | - Anne-Fleur Gaston
- Laboratoire Européen Performance, Santé Altitude, EA4604-Université de Perpignan Via Domitia, Département STAPS, Font-Romeu, France; Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
| | - Marco Vicenzi
- Cardio-Pulmonary Exercise Laboratory, Faculty of Motorskill Science, Université Libre de Bruxelles, Brussels, Belgium; Cardiovascular Diseases Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Department of Clinical Sciences and Community Health, Milan, Italy
| | - Gael Deboeck
- Cardio-Pulmonary Exercise Laboratory, Faculty of Motorskill Science, Université Libre de Bruxelles, Brussels, Belgium
| | - Enric Subirats
- Laboratoire Européen Performance, Santé Altitude, EA4604-Université de Perpignan Via Domitia, Département STAPS, Font-Romeu, France; Catedra de medicina de muntanya I del medi natural I de simulacio clinica, Universitat de Girona, Girona, Spain
| | - Vitalie Faoro
- Cardio-Pulmonary Exercise Laboratory, Faculty of Motorskill Science, Université Libre de Bruxelles, Brussels, Belgium
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Michaelchuk WW, Tedjasaputra V, Bryan TL, van Diepen S, Stickland MK. The effect of dopamine on pulmonary diffusing capacity and capillary blood volume responses to exercise in young healthy humans. Exp Physiol 2019; 104:1952-1962. [PMID: 31603268 DOI: 10.1113/ep088056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 10/08/2019] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the Central question? Does dopamine, a pulmonary vascular vasodilator, contribute to the regulation of pulmonary diffusing capacity and capillary blood volume responses to exercise and exercise tolerance? What are the main findings and their importance? Dopamine appears not to be important for regulating pulmonary diffusing capacity or pulmonary capillary blood volume during exercise in healthy participants. Dopamine blockade trials demonstrated that endogenous dopamine is important for maintaining exercise tolerance; however, exogenous dopamine does not improve exercise tolerance. ABSTRACT Pulmonary capillary blood volume (Vc ) and diffusing membrane capacity (Dm ) expansion are important contributors to the increased pulmonary diffusing capacity (DLCO ) observed during upright exercise. Dopamine is a pulmonary vascular vasodilator, and recent studies suggest that it may play a role in Vc regulation through changes in pulmonary vascular tone. The purpose of this study was to examine the effect of exogenous dopamine and dopamine receptor-2 (D2 -receptor) blockade on DLCO , Vc and Dm at baseline and during cycle exercise, as well as time-to-exhaustion at 85% of V ̇ O 2 peak . We hypothesized that dopamine would increase DLCO , Vc , Dm and time-to-exhaustion, while D2 -receptor blockade would have the opposite effect. We recruited 14 young, healthy, recreationally active subjects ( V ̇ O 2 peak 45.8 ± 6.6 ml kg-1 min-1 ). DLCO , Vc and Dm were determined at baseline and during exercise at 60% and 85% of V ̇ O 2 peak under the following randomly assigned and double blinded conditions: (1) intravenous saline and placebo pill, (2) intravenous dopamine (2 µg kg-1 min-1 ) and placebo pill, and (3) intravenous saline and D2 -receptor antagonist (20 mg oral metoclopramide). Exogenous dopamine and dopamine blockade had no effect on DLCO , Vc and Dm responses at baseline or during exercise. Dopamine blockade reduced time-to-exhaustion by 47% (P = 0.04), but intravenous dopamine did not improve time-to-exhaustion. While dopamine modulation did not affect DLCO , Vc or Dm , the reduction in time-to-exhaustion with D2 -receptor blockade suggests that endogenous dopamine is important for exercise tolerance.
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Affiliation(s)
- Wade W Michaelchuk
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Vincent Tedjasaputra
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Tracey L Bryan
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Sean van Diepen
- Department of Critical Care and Division of Cardiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Michael K Stickland
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,G.F. MacDonald Centre for Lung Health, Covenant Health, Edmonton, Alberta, Canada
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Wright SP, Esfandiari S, Gray T, Fuchs FC, Chelvanathan A, Chan W, Sasson Z, Granton JT, Goodman JM, Mak S. The pulmonary artery wedge pressure response to sustained exercise is time-variant in healthy adults. Heart 2016; 102:438-43. [PMID: 26762239 DOI: 10.1136/heartjnl-2015-308592] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 12/15/2015] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVES The clinical and prognostic significance of 'exaggerated' elevations in pulmonary artery wedge pressure (PAWP) during symptom-limited exercise testing is increasingly recognised. However, the paucity of normative data makes the identification of abnormal responses challenging. Our objectives was to describe haemodynamic responses that reflect normal adaptation to submaximal exercise in a group of community-dwelling, older, non-dyspnoeic adults. METHODS Twenty-eight healthy volunteers (16 men/12 women; 55±6 years) were studied during rest and two consecutive stages of cycle ergometry, at targeted heart rates of 100 bpm (light exercise) and 120 bpm (moderate exercise). Right-heart catheterisation was performed to measure pulmonary artery pressures, both early (2 min) and after sustained (7 min) exercise at each intensity. RESULTS End-expiratory PAWP at baseline was 11±3 mm Hg and increased to 22±5 mm Hg at early-light exercise (p<0.01). At sustained-light exercise, PAWP declined to 17±5 mm Hg, remaining elevated versus baseline (p<0.01). PAWP increased again at early-moderate exercise to 20±6 mm Hg but did not exceed the values observed at early-light exercise, and declined further to 15±5 mm Hg at sustained-moderate exercise (p<0.01 vs baseline). When analysed at 30 s intervals, mean and diastolic pulmonary artery pressures peaked at 180 (IQR=30) s and 130 (IQR=90) s, respectively, and both declined significantly by 420 (IQR=30) s (both p<0.01) of light exercise. Similar temporal patterns were observed at moderate exercise. CONCLUSIONS The range of PAWP responses to submaximal exercise is broad in health, but also time-variant. PAWP may routinely exceed 20 mm Hg early in exercise. Initial increases in PAWP and mean pulmonary artery pressures do not necessarily reflect abnormal cardiopulmonary physiology, as pressures may normalise within a period of minutes.
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Affiliation(s)
- Stephen P Wright
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada
| | - Sam Esfandiari
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada
| | - Taylor Gray
- Department of Exercise Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Felipe C Fuchs
- Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada
| | - Anjala Chelvanathan
- Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada
| | - William Chan
- Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada
| | - Zion Sasson
- Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada
| | - John T Granton
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada Division of Respirology, University Health Network, Toronto, Ontario, Canada
| | - Jack M Goodman
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada Department of Exercise Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Susanna Mak
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada
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Ma JLG, Dutch MJ. Extreme sports: Extreme physiology. Exercise-induced pulmonary oedema. Emerg Med Australas 2013; 25:368-71. [DOI: 10.1111/1742-6723.12101] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2013] [Indexed: 11/29/2022]
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Eldridge MW, Dempsey JA, Haverkamp HC, Lovering AT, Hokanson JS. Exercise-induced intrapulmonary arteriovenous shunting in healthy humans. J Appl Physiol (1985) 2004; 97:797-805. [PMID: 15107409 DOI: 10.1152/japplphysiol.00137.2004] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We hypothesized that increasing exercise intensity recruits dormant arteriovenous intrapulmonary shunts, which may contribute to the widened alveolar-arterial oxygen difference seen with exercise. Twenty-three healthy volunteers (13 men and 10 women, aged 23-48 yr) with normal lung function and a wide range of fitness (mean maximal oxygen uptake = 126% predicted; range = 78-200% predicted) were studied by agitated saline contrast echocardiography (4-chamber apical view). All 23 subjects had normal resting contrast echocardiograms without evidence of intracardiac or intrapulmonary shunting. However, with cycle ergometer exercise, 21 of 23 (91%) of the subjects showed a delayed (>3 cardiac cycles) appearance of contrast bubbles in the left heart. This pattern is consistent with passage of contrast bubbles through the pulmonary circulation. Because the contrast bubbles are known to be significantly larger than pulmonary capillaries, we propose that they are traveling through direct arteriovenous intrapulmonary shunts. In all cases, the intrapulmonary shunting developed at submaximal oxygen uptakes [%maximal oxygen uptake = 59 +/- 20 (SD)] and once evident persisted at all subsequent work rates. Within 3 min of exercise termination, the contrast echocardiograms with bubble injection showed no evidence of intrapulmonary shunting. These dynamic shunts will contribute significantly to the widened alveolar-arterial oxygen difference seen with exercise. They may also act as a protective parallel vascular network limiting the rise in regional pulmonary vascular pressure while preserving cardiac output during exercise.
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Affiliation(s)
- Marlowe W Eldridge
- John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin, Medical School, Madison, Wisconsin 53792-4108, USA.
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Hasuda T, Satoh T, Shimouchi A, Sakamaki F, Kyotani S, Matsumoto T, Goto Y, Nakanishi N. Improvement in exercise capacity with nitric oxide inhalation in patients with precapillary pulmonary hypertension. Circulation 2000; 101:2066-70. [PMID: 10790348 DOI: 10.1161/01.cir.101.17.2066] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Patients with precapillary pulmonary hypertension (PH) exhibit a poor exercise capacity due to an impaired vasodilatory response of their pulmonary arteries. By causing the pulmonary artery to dilate, inhaled nitric oxide (NO) may allow an increase in exercise capacity in patients with PH. METHODS AND RESULTS On 2 separate days, 3 days apart, 14 patients with precapillary PH (10 primary PH, 4 residual PH after correction of an intracardiac shunt; age, 40+/-12 years; mean pulmonary artery pressure, 60+/-23 mm Hg) performed exercise, with and without inhalation of 20 ppm NO, on a cycle ergometer. The work rate was increased 15 W/min until their symptom-limited maximum, with breath-by-breath gas analysis. Patients were randomly and blindly selected to inhale NO on either their first or second test. Peak exercise load and anaerobic threshold tended to increase, but not significantly. Peak oxygen consumption (f1.gif" BORDER="0">O(2)) and Deltaf1.gif" BORDER="0">O(2)/DeltaW ratio increased significantly, by 18% and 22%, respectively (peak f1.gif" BORDER="0">O(2), 13.6+/-3.6 to 16.0+/-4. 1 mL. kg(-1). min(-1); Deltaf1.gif" BORDER="0">O(2)/DeltaW ratio, 5. 8+/-2.4 to 7.1+/-2.3 mL. kg(-1). min(-1). W(-1); both P<0.01). Peak f1.gif" BORDER="0">O(2) increased >10% in 12 of the 14 patients. However, respiratory quotient at peak exercise decreased from 1. 22+/-0.15 to 1.09+/-0.15 (P<0.01). CONCLUSIONS Inhaled NO substantially increases oxygen consumption at the same workload during exercise. This finding supports the possibility of ambulatory NO inhalation therapy in patients with precapillary PH.
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Affiliation(s)
- T Hasuda
- Division of Cardiology and Pulmonary Circulation, Department of Medicine, National Cardiovascular Center, and Division of Circulatory Dynamics, National Cardiovascular Research Institute, Suita, Osaka, Japan
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