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Skow RJ, Sarma S, MacNamara JP, Bartlett MF, Wakeham DJ, Martin ZT, Samels M, Nandadeva D, Brazile TL, Ren J, Fu Q, Babb TG, Balmain BN, Nelson MD, Hynan LS, Levine BD, Fadel PJ, Haykowsky MJ, Hearon CM. Identifying the Mechanisms of a Peripherally Limited Exercise Phenotype in Patients With Heart Failure With Preserved Ejection Fraction. Circ Heart Fail 2024; 17:e011693. [PMID: 39051098 PMCID: PMC11335445 DOI: 10.1161/circheartfailure.123.011693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 06/11/2024] [Indexed: 07/27/2024]
Abstract
BACKGROUND We identified peripherally limited patients using cardiopulmonary exercise testing and measured skeletal muscle oxygen transport and utilization during invasive single leg exercise testing to identify the mechanisms of the peripheral limitation. METHODS Forty-five patients with heart failure with preserved ejection fraction (70±7 years, 27 females) completed seated upright cardiopulmonary exercise testing and were defined as having a (1) peripheral limitation to exercise if cardiac output/oxygen consumption (VO2) was elevated (≥6) or 5 to 6 with a stroke volume reserve >50% (n=31) or (2) a central limitation to exercise if cardiac output/VO2 slope was ≤5 or 5 to 6 with stroke volume reserve <50% (n=14). Single leg knee extension exercise was used to quantify peak leg blood flow (Doppler ultrasound), arterial-to-venous oxygen content difference (femoral venous catheter), leg VO2, and muscle oxygen diffusive conductance. In a subset of participants (n=36), phosphocreatine recovery time was measured by magnetic resonance spectroscopy to determine skeletal muscle oxidative capacity. RESULTS Peak VO2 during cardiopulmonary exercise testing was not different between groups (central: 13.9±5.7 versus peripheral: 12.0±3.1 mL/min per kg; P=0.135); however, the peripheral group had a lower peak arterial-to-venous oxygen content difference (central: 13.5±2.0 versus peripheral: 11.1±1.6 mLO2/dL blood; P<0.001). During single leg knee extension, there was no difference in peak leg VO2 (P=0.306), but the peripherally limited group had greater blood flow/VO2 ratio (P=0.024), lower arterial-to-venous oxygen content difference (central: 12.3±2.5 versus peripheral: 10.3±2.2 mLO2/dL blood; P=0.013), and lower muscle oxygen diffusive conductance (P=0.021). A difference in magnetic resonance spectroscopy-derived phosphocreatine recovery time was not detected (P=0.199). CONCLUSIONS Peripherally limited patients with heart failure with preserved ejection fraction identified by cardiopulmonary exercise testing have impairments in oxygen transport and utilization at the level of the skeletal muscle quantified by invasive knee extension exercise testing, which includes an increased blood flow/V̇O2 ratio and poor muscle diffusive capacity. REGISTRATION URL: https://www.clinicaltrials.gov; Unique identifier: NCT04068844.
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Affiliation(s)
- Rachel J Skow
- Department of Kinesiology, University of Texas at Arlington (R.J.S., M.F.B., Z.T.M., D.N., M.D.N., P.J.F.)
- Faculty of Nursing, College of Health Sciences, University of Alberta, Edmonton, AB, Canada (R.J.S., M.J.H.)
| | - Satyam Sarma
- Institute of Exercise and Environmental Medicine (S.S., J.P.M., D.J.W., M.S., T.L.B., Q.F., T.G.B., B.N.B., B.D.L., C.M.H.), University of Texas Southwestern Medical Center, Dallas
| | - James P MacNamara
- Institute of Exercise and Environmental Medicine (S.S., J.P.M., D.J.W., M.S., T.L.B., Q.F., T.G.B., B.N.B., B.D.L., C.M.H.), University of Texas Southwestern Medical Center, Dallas
| | - Miles F Bartlett
- Department of Kinesiology, University of Texas at Arlington (R.J.S., M.F.B., Z.T.M., D.N., M.D.N., P.J.F.)
| | - Denis J Wakeham
- Institute of Exercise and Environmental Medicine (S.S., J.P.M., D.J.W., M.S., T.L.B., Q.F., T.G.B., B.N.B., B.D.L., C.M.H.), University of Texas Southwestern Medical Center, Dallas
| | - Zachary T Martin
- Department of Kinesiology, University of Texas at Arlington (R.J.S., M.F.B., Z.T.M., D.N., M.D.N., P.J.F.)
- Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA (Z.T.M.)
| | - Mitchel Samels
- Institute of Exercise and Environmental Medicine (S.S., J.P.M., D.J.W., M.S., T.L.B., Q.F., T.G.B., B.N.B., B.D.L., C.M.H.), University of Texas Southwestern Medical Center, Dallas
| | - Damsara Nandadeva
- Department of Kinesiology, University of Texas at Arlington (R.J.S., M.F.B., Z.T.M., D.N., M.D.N., P.J.F.)
- Department of Physiology, Faculty of Medicine, University of Peradeniya, Sri Lanka (D.N.)
| | - Tiffany L Brazile
- Institute of Exercise and Environmental Medicine (S.S., J.P.M., D.J.W., M.S., T.L.B., Q.F., T.G.B., B.N.B., B.D.L., C.M.H.), University of Texas Southwestern Medical Center, Dallas
| | - Jimin Ren
- Advanced Imaging Research Center (J.R.), University of Texas Southwestern Medical Center, Dallas
- Department of Radiology (J.R.), University of Texas Southwestern Medical Center, Dallas
| | - Qi Fu
- Institute of Exercise and Environmental Medicine (S.S., J.P.M., D.J.W., M.S., T.L.B., Q.F., T.G.B., B.N.B., B.D.L., C.M.H.), University of Texas Southwestern Medical Center, Dallas
| | - Tony G Babb
- Institute of Exercise and Environmental Medicine (S.S., J.P.M., D.J.W., M.S., T.L.B., Q.F., T.G.B., B.N.B., B.D.L., C.M.H.), University of Texas Southwestern Medical Center, Dallas
| | - Bryce N Balmain
- Institute of Exercise and Environmental Medicine (S.S., J.P.M., D.J.W., M.S., T.L.B., Q.F., T.G.B., B.N.B., B.D.L., C.M.H.), University of Texas Southwestern Medical Center, Dallas
| | - Michael D Nelson
- Department of Kinesiology, University of Texas at Arlington (R.J.S., M.F.B., Z.T.M., D.N., M.D.N., P.J.F.)
| | - Linda S Hynan
- Peter O'Donnell Jr School of Public Health and Department of Psychiatry (L.S.H.), University of Texas Southwestern Medical Center, Dallas
| | - Benjamin D Levine
- Institute of Exercise and Environmental Medicine (S.S., J.P.M., D.J.W., M.S., T.L.B., Q.F., T.G.B., B.N.B., B.D.L., C.M.H.), University of Texas Southwestern Medical Center, Dallas
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington (R.J.S., M.F.B., Z.T.M., D.N., M.D.N., P.J.F.)
| | - Mark J Haykowsky
- Faculty of Nursing, College of Health Sciences, University of Alberta, Edmonton, AB, Canada (R.J.S., M.J.H.)
| | - Christopher M Hearon
- Institute of Exercise and Environmental Medicine (S.S., J.P.M., D.J.W., M.S., T.L.B., Q.F., T.G.B., B.N.B., B.D.L., C.M.H.), University of Texas Southwestern Medical Center, Dallas
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2
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MacNamara JP, Turlington WM, Dias KA, Hearon CM, Ivey E, Delgado VA, Brazile TL, Wakeham DJ, Turer AT, Link MS, Levine BD, Sarma S. Impaired longitudinal systolic-diastolic coupling and cardiac response to exercise in patients with hypertrophic cardiomyopathy. Echocardiography 2024; 41:e15857. [PMID: 38895911 PMCID: PMC11250570 DOI: 10.1111/echo.15857] [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: 03/06/2024] [Revised: 05/22/2024] [Accepted: 05/23/2024] [Indexed: 06/21/2024] Open
Abstract
BACKGROUND In patients with hypertrophic cardiomyopathy (HCM), impaired augmentation of stroke volume and diastolic dysfunction contribute to exercise intolerance. Systolic-diastolic (S-D) coupling characterizes how systolic contraction of the left ventricle (LV) primes efficient elastic recoil during early diastole. Impaired S-D coupling may contribute to the impaired cardiac response to exercise in patients with HCM. METHODS Patients with HCM (n = 25, age = 47 ± 9 years) and healthy adults (n = 115, age = 49 ± 10 years) underwent a cardiopulmonary exercise testing (CPET) and echocardiogram. S-D coupling was defined as the ratio of LV longitudinal excursion of the mitral annulus during early diastole (EDexc) and systole (Sexc) and compared between groups. Peak oxygen uptake (peak V̇O2) (Douglas bags), cardiac index (C2H2 rebreathe), and stroke volume index (SVi) were assessed during CPET. Linear regression was performed between S-D coupling and peak V̇O2, peak cardiac index, and peak SVi. RESULTS S-D coupling was lower in HCM (Controls: 0.63 ± 0.08, HCM: 0.56 ± 0.10, p < 0.001). Peak V̇O2 and stroke volume reserve were lower in patients with HCM (Peak VO2 Controls: 28.5 ± 5.5, HCM: 23.7 ± 7.2 mL/kg/min, p < 0.001, SV reserve: Controls 39 ± 16, HCM 30 ± 18 mL, p = 0.008). In patients with HCM, S-D coupling was associated with peak V̇O2 (r = 0.47, p = 0.018), peak cardiac index (r = 0.60, p = 0.002), and peak SVi (r = 0.63, p < 0.001). CONCLUSION Systolic-diastolic coupling was impaired in patients with HCM and was associated with fitness and the cardiac response to exercise. Inefficient S-D coupling may link insufficient stroke volume generation, diastolic dysfunction, and exercise intolerance in HCM.
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Affiliation(s)
- James P MacNamara
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - William M Turlington
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Katrin A Dias
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
| | - Christopher M Hearon
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Erika Ivey
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
| | - Vincent A Delgado
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Tiffany L Brazile
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Denis J Wakeham
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Aslan T Turer
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Mark S Link
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Benjamin D Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Satyam Sarma
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Bano M, Hussain T, Samels MR, Butts RJ, Kirk R, Levine BD. Cardiovascular remodelling in response to exercise training in patients after the Fontan procedure: a pilot study. Cardiol Young 2024; 34:604-613. [PMID: 37664999 DOI: 10.1017/s1047951123003153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
BACKGROUND The cardiovascular adaptations associated with structured exercise training in Fontan patients remain unknown. We hypothesised that short-term training causes cardiac remodelling and parallel improvement in maximal exercise capacity (VO2 max) in these patients. METHODS AND RESULTS Five patients, median age 19.5 (17.6-21.3) years, with a history of Fontan operation meeting inclusion/exclusion criteria, participated in a 3-month training programme designed to improve endurance. Magnetic resonance images for assessment of cardiac function, fibrosis, cardiac output, and liver elastography to assess stiffness were obtained at baseline and after training. Maximal exercise capacity (VO2 max) and cardiac output Qc (effective pulmonary blood flow) at rest and during exercise were measured (C2H2 rebreathing) at the same interval. VO2 max increased from median (IQR) 27.2 (26-28.7) to 29.6 (28.5-32.2) ml/min/kg (p = 0.04). There was an improvement in cardiac output (Qc) during maximal exercise testing from median (IQR) 10.3 (10.1-12.3) to 12.3 (10.9-14.9) l/min, but this change was variable (p = 0.14). Improvement in VO2 max correlated with an increase in ventricular mass (r = 0.95, p = 0.01), and improvement in Quality-of-life inventory (PedsQL) Cardiac scale scores for patient-reported symptoms (r = 0.90, p = 0.03) and cognitive problems (r = 0.89, p = 0.04). The correlation between VO2 max and Qc showed a positive trend but was not significant (r = 0.8, p = 0.08). No adverse cardiac or liver adaptations were noted. CONCLUSION Short-term training improved exercise capacity in this Fontan pilot without any adverse cardiac or liver adaptations. These results warrant further study in a larger population and over a longer duration of time. TRIAL REGISTRATION NUMBER NCT03263312, Unique Protocol ID: STU 122016-037; Registration Date: 18 January, 2017.
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Affiliation(s)
- Maria Bano
- Department of Pediatrics, Division of Cardiology, UT Southwestern, Dallas, TX, USA
| | - Tarique Hussain
- Department of Pediatrics, Division of Cardiology, UT Southwestern, Dallas, TX, USA
| | - Mitchel R Samels
- Institute of Exercise and Environmental Medicine, Dallas, TX, USA
| | - Ryan J Butts
- Department of Pediatrics, Division of Cardiology, UT Southwestern, Dallas, TX, USA
| | - Richard Kirk
- Department of Pediatric Cardiology and Cardiac Surgery, Ospedale Pediatrico Bambino Gesu, Rome, Itlay
| | - Benjamin D Levine
- Institute of Exercise and Environmental Medicine, Dallas, TX, USA
- Department of Internal Medicine, Division of Cardiology, UT Southwestern, Dallas, TX, USA
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Bostad W, Gibala MJ. Response. Med Sci Sports Exerc 2024; 56:157-158. [PMID: 37625165 DOI: 10.1249/mss.0000000000003286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/27/2023]
Affiliation(s)
- William Bostad
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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D'Souza AW, Yoo JK, Bhai S, Sarma S, Anderson EH, Levine BD, Fu Q. Attenuated peripheral oxygen extraction and greater cardiac output in women with posttraumatic stress disorder during exercise. J Appl Physiol (1985) 2024; 136:141-150. [PMID: 38031720 PMCID: PMC11219012 DOI: 10.1152/japplphysiol.00161.2023] [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: 03/15/2023] [Revised: 11/20/2023] [Accepted: 11/20/2023] [Indexed: 12/01/2023] Open
Abstract
Posttraumatic stress disorder (PTSD) is associated with an increased risk of developing cardiovascular disease, especially in women. Evidence indicates that men with PTSD exhibit lower maximal oxygen uptake (V̇o2max) relative to controls; however, whether V̇o2max is blunted in women with PTSD remains unknown. Furthermore, it is unclear what determinants (i.e., central and/or peripheral) of V̇o2max are impacted by PTSD. Therefore, we evaluated the central (i.e., cardiac output; Q̇c) and peripheral (i.e., arteriovenous oxygen difference) determinants of V̇o2max in women with PTSD; hypothesizing that V̇o2max would be lower in women with PTSD compared with women without PTSD (controls), primarily due to smaller increases in stroke volume (SV), and therefore Q̇c. Oxygen uptake (V̇o2), heart rate (HR), Q̇c, SV, and arteriovenous oxygen difference were measured in women with PTSD (n = 14; mean [SD]: 43 [11] yr,) and controls (n = 17; 45 [11] yr) at rest, and during an incremental maximal treadmill exercise test, and the Q̇c/V̇o2 slope was calculated. V̇o2max was not different between women with and without PTSD (24.3 [5.6] vs. 26.4 [5.0] mL/kg/min; P = 0.265). However, women with PTSD had higher Q̇c [P = 0.002; primarily due to greater SV (P = 0.069), not HR (P = 0.285)], and lower arteriovenous oxygen difference (P = 0.002) throughout exercise compared with controls. Furthermore, the Q̇c/V̇o2 slope was steeper in women with PTSD relative to controls (6.6 [1.4] vs. 5.7 [1.0] AU; P = 0.033). Following maximal exercise, women with PTSD exhibited slower HR recovery than controls (P = 0.046). Thus, despite attenuated peripheral oxygen extraction, V̇o2max is not reduced in women with PTSD, likely due to larger increases in Q̇c.NEW & NOTEWORTHY The current study indicates that V̇o2max is not different between women with and without PTSD; however, women with PTSD exhibit blunted peripheral extraction of oxygen, thus requiring an increase in Q̇c to meet metabolic demand during exercise. Furthermore, following exercise, women with PTSD demonstrate impaired autonomic cardiovascular control relative to sedentary controls. We interpret these data to indicate that women with PTSD demonstrate aberrant cardiovascular responses during and immediately following fatiguing exercise.
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Affiliation(s)
- Andrew W D'Souza
- Neurovascular Research Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Jeung-Ki Yoo
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Salman Bhai
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Satyam Sarma
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Elizabeth H Anderson
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Veterans Affairs North Texas Health Care System, Dallas, Texas, United States
| | - Benjamin D Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
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Bostad W, Williams JS, Van Berkel EK, Richards DL, MacDonald MJ, Gibala MJ. Biological sex does not influence the peak cardiac output response to twelve weeks of sprint interval training. Sci Rep 2023; 13:22995. [PMID: 38151488 PMCID: PMC10752867 DOI: 10.1038/s41598-023-50016-4] [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: 08/15/2023] [Accepted: 12/14/2023] [Indexed: 12/29/2023] Open
Abstract
Sprint interval training (SIT) increases peak oxygen uptake (V̇O2peak) but the mechanistic basis is unclear. We have reported that 12 wk of SIT increased V̇O2peak and peak cardiac output (Q̇peak) and the changes in these variables were correlated. An exploratory analysis suggested that Q̇peak increased in males but not females. The present study incorporated best practices to examine the potential influence of biological sex on the Q̇peak response to SIT. Male and female participants (n = 10 each; 21 ± 4 y) performed 33 ± 2 sessions of SIT over 12 wk. Each 10-min session involved 3 × 20-s 'all-out' sprints on an ergometer. V̇O2peak increased after SIT (3.16 ± 1.0 vs. 2.89 ± 1.0 L/min, η2p = 0.53, p < 0.001) with no sex × time interaction (p = 0.61). Q̇peak was unchanged after training (15.2 ± 3.3 vs. 15.1 ± 3.0 L/min, p = 0.85), in contrast to our previous study. The peak estimated arteriovenous oxygen difference increased after training (204 ± 30 vs. 187 ± 36 ml/L, p = 0.006). There was no effect of training or sex on measures of endothelial function. We conclude that 12 wk of SIT increases V̇O2peak but the mechanistic basis remains unclear. The capacity of inert gas rebreathing to assess changes in Q̇peak may be limited and invasive studies that use more direct measures are needed.
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Affiliation(s)
- William Bostad
- Department of Kinesiology, McMaster University, Ivor Wynne Centre, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Jennifer S Williams
- Department of Kinesiology, McMaster University, Ivor Wynne Centre, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Emily K Van Berkel
- Department of Kinesiology, McMaster University, Ivor Wynne Centre, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Douglas L Richards
- Department of Medicine, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Maureen J MacDonald
- Department of Kinesiology, McMaster University, Ivor Wynne Centre, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Martin J Gibala
- Department of Kinesiology, McMaster University, Ivor Wynne Centre, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada.
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Wakeham DJ, Ivey E, Saland SA, Lewis JS, Palmer D, Morris M, Bleich JL, Weyand PG, Brazile TL, Hearon CM, Sarma S, MacNamara JP, Hieda M, Levine BD. Effects of Synchronizing Foot Strike and Cardiac Phase on Exercise Hemodynamics in Patients With Cardiac Resynchronization Therapy: A Within-Subjects Pilot Study to Fine-Tune Cardio-Locomotor Coupling for Heart Failure. Circulation 2023; 148:2008-2016. [PMID: 37830218 PMCID: PMC11032184 DOI: 10.1161/circulationaha.123.066170] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 09/26/2023] [Indexed: 10/14/2023]
Abstract
BACKGROUND Despite advances in medical and cardiac resynchronization therapy (CRT), individuals with chronic congestive heart failure (CHF) have persistent symptoms, including exercise intolerance. Optimizing cardio-locomotor coupling may increase stroke volume and skeletal muscle perfusion as previously shown in healthy runners. Therefore, we tested the hypothesis that exercise stroke volume and cardiac output would be higher during fixed-paced walking when steps were synchronized with the diastolic compared with systolic portion of the cardiac cycle in patients with CHF and CRT. METHODS Ten participants (58±17 years of age; 40% female) with CHF and previously implanted CRT pacemakers completed 5-minute bouts of walking on a treadmill (range, 1.5-3 mph). Participants were randomly assigned to first walking to an auditory tone to synchronize their foot strike to either the systolic (0% or 100±15% of the R-R interval) or diastolic phase (45±15% of the R-R interval) of their cardiac cycle and underwent assessments of oxygen uptake (V̇o2; indirect calorimetry) and cardiac output (acetylene rebreathing). Data were compared through paired-samples t tests. RESULTS V̇o2 was similar between conditions (diastolic 1.02±0.44 versus systolic 1.05±0.42 L/min; P=0.299). Compared with systolic walking, stroke volume (diastolic 80±28 versus systolic 74±26 mL; P=0.003) and cardiac output (8.3±3.5 versus 7.9±3.4 L/min; P=0.004) were higher during diastolic walking; heart rate (paced) was not different between conditions. Mean arterial pressure was significantly lower during diastolic walking (85±12 versus 98±20 mm Hg; P=0.007). CONCLUSIONS In patients with CHF who have received CRT, diastolic stepping increases stroke volume and oxygen delivery and decreases afterload. We speculate that, if added to pacemakers, this cardio-locomotor coupling technology may maximize CRT efficiency and increase exercise participation and quality of life in patients with CHF.
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Affiliation(s)
- Denis J Wakeham
- University of Texas Southwestern Medical Center, Dallas (D.J.W., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (D.J.W. E.I., S.A.S., J.S.L., D.P., M.M., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
| | - Erika Ivey
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (D.J.W. E.I., S.A.S., J.S.L., D.P., M.M., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
| | - Sophie A Saland
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (D.J.W. E.I., S.A.S., J.S.L., D.P., M.M., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
| | - Joshua S Lewis
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (D.J.W. E.I., S.A.S., J.S.L., D.P., M.M., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
| | - Dean Palmer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (D.J.W. E.I., S.A.S., J.S.L., D.P., M.M., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
| | - Margot Morris
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (D.J.W. E.I., S.A.S., J.S.L., D.P., M.M., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
| | | | - Peter G Weyand
- Locomotor Performance Laboratory, Department of Applied Physiology & Wellness, Southern Methodist University, Dallas, TX (P.G.W.)
| | - Tiffany L Brazile
- University of Texas Southwestern Medical Center, Dallas (D.J.W., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (D.J.W. E.I., S.A.S., J.S.L., D.P., M.M., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
| | - Christopher M Hearon
- University of Texas Southwestern Medical Center, Dallas (D.J.W., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (D.J.W. E.I., S.A.S., J.S.L., D.P., M.M., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
| | - Satyam Sarma
- University of Texas Southwestern Medical Center, Dallas (D.J.W., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (D.J.W. E.I., S.A.S., J.S.L., D.P., M.M., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
| | - James P MacNamara
- University of Texas Southwestern Medical Center, Dallas (D.J.W., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (D.J.W. E.I., S.A.S., J.S.L., D.P., M.M., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
| | - Michinari Hieda
- University of Texas Southwestern Medical Center, Dallas (D.J.W., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (D.J.W. E.I., S.A.S., J.S.L., D.P., M.M., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
| | - Benjamin D Levine
- University of Texas Southwestern Medical Center, Dallas (D.J.W., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (D.J.W. E.I., S.A.S., J.S.L., D.P., M.M., T.L.B., C.M.H., S.S., J.P.M., M.H., B.D.L.)
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8
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MacNamara JP, Dias KA, Hearon CM, Ivey E, Delgado VA, Saland S, Samels M, Hieda M, Turer AT, Link MS, Sarma S, Levine BD. Randomized Controlled Trial of Moderate- and High-Intensity Exercise Training in Patients With Hypertrophic Cardiomyopathy: Effects on Fitness and Cardiovascular Response to Exercise. J Am Heart Assoc 2023; 12:e031399. [PMID: 37830338 PMCID: PMC10757533 DOI: 10.1161/jaha.123.031399] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 09/20/2023] [Indexed: 10/14/2023]
Abstract
Background Moderate intensity exercise training (MIT) is safe and effective for patients with hypertrophic cardiomyopathy, yet the efficacy of high intensity training (HIT) remains unknown. This study aimed to compare the efficacy of HIT compared with MIT in patients with hypertrophic cardiomyopathy. Methods and Results Patients with hypertrophic cardiomyopathy were randomized to either 5 months of MIT, or 1 month of MIT followed by 4 months of progressive HIT. Peak oxygen uptake (V˙O2; Douglas bags), cardiac output (acetylene rebreathing), and arteriovenous oxygen difference (Fick equation) were measured before and after training. Left ventricular outflow gradient and volumes were measured by echocardiography. Fifteen patients completed training (MIT, n=8, age 52±7 years; HIT, n=7, age 42±8 years). Both HIT and MIT improved peak V˙O2 by 1.3 mL/kg per min (P=0.009). HIT (+1.5 mL/kg per min) had a slightly greater effect than MIT (+1.1 mL/kg per min) but with no statistical difference (group×exercise P=0.628). A greater augmentation of arteriovenous oxygen difference occurred with exercise (Δ1.6 mL/100 mL P=0.005). HIT increased left ventricular end-diastolic volume (+17 mL, group×exercise P=0.015) compared with MIT. No serious arrhythmias or adverse cardiac events occurred. Conclusions This randomized trial of exercise training in patients with hypertrophic cardiomyopathy demonstrated that both HIT and MIT improved fitness without clear superiority of either. Although the study was underpowered for safety outcomes, no serious adverse events occurred. Exercise training resulted in salutary peripheral and cardiac adaptations. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03335332.
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Affiliation(s)
- James P. MacNamara
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian DallasDallasTXUSA
- University of Texas Southwestern Medical CenterDallasTXUSA
| | - Katrin A. Dias
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian DallasDallasTXUSA
| | - Christopher M. Hearon
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian DallasDallasTXUSA
- University of Texas Southwestern Medical CenterDallasTXUSA
| | - Erika Ivey
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian DallasDallasTXUSA
| | | | - Sophie Saland
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian DallasDallasTXUSA
| | - Mitchel Samels
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian DallasDallasTXUSA
| | - Michinari Hieda
- Department of Medicine and Biosystemic Science, Hematology, Oncology, and Cardiovascular Medicine, School of MedicineKyushu UniversityFukuokaJapan
| | - Aslan T. Turer
- University of Texas Southwestern Medical CenterDallasTXUSA
| | - Mark S. Link
- University of Texas Southwestern Medical CenterDallasTXUSA
| | - Satyam Sarma
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian DallasDallasTXUSA
- University of Texas Southwestern Medical CenterDallasTXUSA
| | - Benjamin D. Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian DallasDallasTXUSA
- University of Texas Southwestern Medical CenterDallasTXUSA
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9
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McCarthy DG, Bostad W, Bone J, Powley FJ, Richards DL, Gibala MJ. Effect of Acute Ketone Monoester Ingestion on Cardiorespiratory Responses to Exercise and the Influence of Blood Acidosis. Med Sci Sports Exerc 2023; 55:1286-1295. [PMID: 36849121 DOI: 10.1249/mss.0000000000003141] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
PURPOSE This study aimed to examine the effect of KE ingestion on exercise cardiac output ( Q˙ ) and the influence of blood acidosis. We hypothesized that KE versus placebo ingestion would increase Q ˙, and coingestion of the pH buffer bicarbonate would mitigate this effect. METHODS In a randomized, double-blind, crossover manner, 15 endurance-trained adults (peak oxygen uptake (V̇O 2peak ), 60 ± 9 mL·kg -1 ·min -1 ) ingested either 0.2 g·kg -1 sodium bicarbonate or a salt placebo 60 min before exercise, and 0.6 g·kg -1 KE or a ketone-free placebo 30 min before exercise. Supplementation yielded three experimental conditions: basal ketone bodies and neutral pH (CON), hyperketonemia and blood acidosis (KE), and hyperketonemia and neutral pH (KE + BIC). Exercise involved 30 min of cycling at ventilatory threshold intensity, followed by determinations of V̇O 2peak and peak Q ˙. RESULTS Blood [β-hydroxybutyrate], a ketone body, was higher in KE (3.5 ± 0.1 mM) and KE + BIC (4.4 ± 0.2) versus CON (0.1 ± 0.0, P < 0.0001). Blood pH was lower in KE versus CON (7.30 ± 0.01 vs 7.34 ± 0.01, P < 0.001) and KE + BIC (7.35 ± 0.01, P < 0.001). Q ˙ during submaximal exercise was not different between conditions (CON: 18.2 ± 3.6, KE: 17.7 ± 3.7, KE + BIC: 18.1 ± 3.5 L·min -1 ; P = 0.4). HR was higher in KE (153 ± 9 bpm) and KE + BIC (154 ± 9) versus CON (150 ± 9, P < 0.02). V̇O 2peak ( P = 0.2) and peak Q ˙ ( P = 0.3) were not different between conditions, but peak workload was lower in KE (359 ± 61 W) and KE + BIC (363 ± 63) versus CON (375 ± 64, P < 0.02). CONCLUSIONS KE ingestion did not increase Q ˙ during submaximal exercise despite a modest elevation of HR. This response occurred independent of blood acidosis and was associated with a lower workload at V̇O 2peak .
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Affiliation(s)
- Devin G McCarthy
- Department of Kinesiology, McMaster University, Hamilton, ON, CANADA
| | - William Bostad
- Department of Kinesiology, McMaster University, Hamilton, ON, CANADA
| | - Jack Bone
- Department of Kinesiology, McMaster University, Hamilton, ON, CANADA
| | - Fiona J Powley
- Department of Kinesiology, McMaster University, Hamilton, ON, CANADA
| | | | - Martin J Gibala
- Department of Kinesiology, McMaster University, Hamilton, ON, CANADA
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10
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Hearon CM, Reddy S, Dias KA, Shankar A, MacNamara J, Levine B, Sarma S. Characterizing regional and global effects of epicardial adipose tissue on cardiac systolic and diastolic function. Obesity (Silver Spring) 2023; 31:1884-1893. [PMID: 37368514 DOI: 10.1002/oby.23782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/16/2023] [Accepted: 03/24/2023] [Indexed: 06/29/2023]
Abstract
OBJECTIVE The aim of this retrospective study was to determine whether regional epicardial adipose tissue (EAT) exerts localized effects on adjacent myocardial left ventricular (LV) function. METHODS Cardiac magnetic resonance imaging (MRI), echocardiography, dual-energy x-ray absorptiometry, and exercise testing were performed in 71 patients with obesity with elevated cardiac biomarkers and visceral fat. Total and regional (anterior, inferior, lateral, right ventricular) EAT was quantified by MRI. Diastolic function was quantified by echocardiography. MRI was used to quantify regional longitudinal LV strain. RESULTS EAT was associated with visceral adiposity (r = 0.47, p < 0.0001) but not total fat mass. Total EAT was associated with markers of diastolic function (early tissue Doppler relaxation velocity [e'], mitral inflow velocity ratio [E/A], early mitral inflow/e' ratio [E/e']), but only E/A remained significant after adjustment for visceral adiposity (r = -0.30, p = 0.015). Right ventricular and LV EAT had similar associations with diastolic function. There was no evidence for localized effects of regional EAT deposition on adjacent regional longitudinal strain. CONCLUSIONS There was no association between regional EAT deposition and corresponding regional LV segment function. Furthermore, the association between total EAT and diastolic function was attenuated after adjustment for visceral fat, indicating that systemic metabolic impairments contribute to diastolic dysfunction in high-risk middle-aged adults.
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Affiliation(s)
- Christopher M Hearon
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Shiva Reddy
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Katrin A Dias
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Aditi Shankar
- Department of Internal Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
| | - James MacNamara
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Benjamin Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Satyam Sarma
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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11
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Reynolds E, Curry K, Barton G, Chandra A, Crandall CG, Berry JD. Impact of the Insoluble Gas Concentration on Measured Stroke Volume at Rest and Submaximal Exercise Using the Innocor Device. Med Sci Sports Exerc 2023; 55:601-606. [PMID: 36251384 DOI: 10.1249/mss.0000000000003073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION The Innocor® device uses an insoluble gas (SF 6 ) to estimate lung volume and the rate of disappearance of a soluble gas (nitrous oxide) to measure pulmonary blood flow (PBF), which approximates cardiac output assuming no shunt. We sought to identify error in the measurement of the insoluble gas in an effort to reduce variation in Innocor® measurement. METHODS We enrolled 28 participants from the Dallas Heart Study (mean age, 63 yr; 57% men; 43% White). Stroke volume was measured at rest and at submaximal (20 and 40 W) exercise using both echocardiography (Philips iE33) and the Innocor® device. We defined a priori peak and equilibrium SF 6 measurement errors as greater or less than 20% of the mean observed value. Three Innocor measurements were obtained at rest ( n = 27) for a total of 81 measurements. Of these, 22% had SF 6 measurements that fell outside of the a priori range. RESULTS Resting Innocor® stroke volume measures with peak SF 6 measured above a priori range (>0.12%) was associated with larger stroke volumes compared with stroke volume measures without peak SF 6 error (101.4 [26.8] vs 64.9 [8.7] mL; P = 0.006) and overestimated stroke volume when compared with stroke volume by echo (101.4 [26.8] vs 59.9 [16.3] mL; P = 0.017). A similar pattern was observed at submaximal exercise. In contrast, there was no consistent association between variation in equilibrium SF 6 concentrations and measured stroke volume. CONCLUSIONS Variability in peak SF 6 concentration is common while using the Innocor® device and results in overestimated stroke volume. These findings have implications for research protocols using this device.
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Affiliation(s)
- Eli Reynolds
- Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas, TX
| | - Karrie Curry
- Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas, TX
| | - Gregory Barton
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas, TX
| | - Alvin Chandra
- Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas, TX
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12
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Kelley EF, Carlson AR, Wentz RJ, Ziegler BL, Johnson BD. Influence of rapidly oscillating inspired O 2 and N 2 concentrations on pulmonary vascular function and lung fluid balance in healthy adults. Front Physiol 2022; 13:1018057. [PMID: 36569769 PMCID: PMC9768664 DOI: 10.3389/fphys.2022.1018057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 11/15/2022] [Indexed: 12/12/2022] Open
Abstract
Introduction: Aircrew may experience rapidly oscillating inspired O2/N2 ratios owing to fluctuations in the on-board oxygen delivery systems (OBOG). Recent investigations suggest these oscillations may contribute to the constellation of physiologic events in aircrew of high-performance aircraft. Therefore, the purpose of this study was to determine whether these "operationally-relevant" environmental challenges may cause decrements in measures of pulmonary vascular physiology. Methods: Thirty healthy participants (Age: 29 ± 5 years) were recruited and assigned to one of the three exposures. Participants were instrumented for physiologic monitoring and underwent baseline cardiopulmonary physiology testing (ground level) consisting of a rebreathe method for quantifying pulmonary blood flow (Qc), pulmonary capillary blood volume (Vc) and alveolar-capillary conductance (Dm). Ultrasound was used to quantify "comet tails" (measure of lung fluid balance). After baseline testing, the participants had two 45 min exposures to an altitude of 8,000 ft where they breathed from gas mixtures alternating between 80/20 and 30/70 O2/N2 ratios at the required frequency (30 s, 60 s, or 120 s), separated by repeat baseline measure. Immediately and 45 min after the second exposure, baseline measures were repeated. Results: We observed no changes in Qc, Dm or Vc during the 60 s exposures. In response to the 30 s oscillation exposure, there was a significantly reduced Qc and Vc at the post-testing period (p = 0.03). Additionally, exposure to the 120 s oscillations resulted in a significant decrease in Vc at the recovery testing period and an increase in the Dm/Vc ratio at both the post and recovery period (p < 0.01). Additionally, we observed no changes in the number of comet tails. Conclusion: These data suggest "operationally-relevant" changes in inspired gas concentrations may cause an acute, albeit mild pulmonary vascular derecruitment, reduced distention and/or mild pulmonary-capillary vasoconstriction, without significant changes in lung fluid balance or respiratory gas exchange. The operational relevance remains less clear, particularly in the setting of additional environmental stressors common during flight (e.g., g forces).
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Affiliation(s)
- Eli F. Kelley
- AFRL, 711HPW, WPAFB, Dayton, OH, United States,*Correspondence: Eli F. Kelley,
| | - Alex R. Carlson
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States
| | - Robert J. Wentz
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States
| | - Briana L. Ziegler
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States
| | - Bruce D. Johnson
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States
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13
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MacNamara JP, Dias KA, Hearon CM, Hieda M, Turer AT, Link MS, Sarma S, Levine BD. Limits to Submaximal and Maximal Exercise in Patients with Hypertrophic Cardiomyopathy. J Appl Physiol (1985) 2022; 133:787-797. [PMID: 35952351 DOI: 10.1152/japplphysiol.00566.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Patients with hypertrophic cardiomyopathy (HCM) often have reduced exercise capacity, and it is unclear whether cardiovascular regulation during exercise is intact in these patients. We aimed to determine the relationship between cardiac output (Q̇c) and oxygen uptake (V̇O2), and stroke volume (SV) reserve in HCMcompared to healthy participants and participants with left ventricular hypertrophy (LVH) but not HCM. METHODS Sixteen patients with HCM (48±7 years, 44% female), 16 participants with LVH (49±5 years, 44% female), and 61 healthy controls (CON: 52±5 years, 52% female) completed submaximal steady-state treadmill exercise followed by a maximal exercise test. V̇O2, Q̇c,SV and arterio-venous oxygen difference were measured during rest and exercise, and Q̇c/V̇O2 slopes were constructed. RESULTS The Q̇c/V̇O2 slopewas blunted in HCM compared to CON and LVH (HCM 4.9±0.7 vs. CON 5.5± 1.0 [P = 0.027], vs LVH 6.0±1.0AU [P = 0.002]) and participants with HCM had a lower SV reserve (HCM 53±33%, controls 83±33%, LVH 82±22%; HCM vs. controls P = 0.002; HCM vs. LVH P = 0.015). Despite a blunted Q̇c/V̇O2 slope, 75% of patients with HCM achieved ≥80% predicted V̇O2max by augmenting a-vO2 difference at maximal exercise (16.0±0.8 mL/100mL vs 13.8±2.7 mL/100mL, P = 0.021). CONCLUSIONS Patients with HCM do not appropriately match Q̇c to metabolic demand, primarily due to inadequate stroke volume augmentation. Despite this central limitation, many patients achieve normal exercise capacities by significantly increasing peripheral oxygen extraction.
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Affiliation(s)
- James P MacNamara
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, United States.,University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Katrin A Dias
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, United States.,University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Christopher M Hearon
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, United States.,University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Michinari Hieda
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, United States.,University of Texas Southwestern Medical Center, Dallas, TX, United States.,Kyushu University, School of Medicine, Department of Medicine and Biosystemic Science, Fukuoka, Japan
| | - Aslan T Turer
- University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Mark S Link
- University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Satyam Sarma
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, United States.,University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Benjamin D Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, United States.,University of Texas Southwestern Medical Center, Dallas, TX, United States
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14
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Hearon CM, Samels M, Dias KA, MacNamara JP, Levine BD, Sarma S. Isolated knee extensor exercise training improves skeletal muscle vasodilation, blood flow, and functional capacity in patients with HFpEF. Physiol Rep 2022; 10:e15419. [PMID: 35924338 PMCID: PMC9350466 DOI: 10.14814/phy2.15419] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 05/07/2023] Open
Abstract
Patients with HFpEF experience severe exercise intolerance due in part to peripheral vascular and skeletal muscle impairments. Interventions targeting peripheral adaptations to exercise training may reverse vascular dysfunction, increase peripheral oxidative capacity, and improve functional capacity in HFpEF. Determine if 8 weeks of isolated knee extension exercise (KE) training will reverse vascular dysfunction, peripheral oxygen utilization, and exercise capacity in patients with HFpEF. Nine HFpEF patients (66 ± 5 years, 6 females) performed graded IKE exercise (5, 10, and 15 W) and maximal exercise testing (cycle ergometer) before and after IKE training (3x/week, 30 min/leg). Femoral blood flow (ultrasound) and leg vascular conductance (LVC; index of vasodilation) were measured during graded IKE exercise. Peak pulmonary oxygen uptake (V̇O2 ; Douglas bags) and cardiac output (QC ; acetylene rebreathe) were measured during graded maximal cycle exercise. IKE training improved LVC (pre: 810 ± 417, post: 1234 ± 347 ml/min/100 mmHg; p = 0.01) during 15 W IKE exercise and increased functional capacity by 13% (peak V̇O2 during cycle ergometry; pre:12.4 ± 5.2, post: 14.0 ± 6.0 ml/min/kg; p = 0.01). The improvement in peak V̇O2 was independent of changes in Q̇c (pre:12.7 ± 3.5, post: 13.2 ± 3.9 L/min; p = 0.26) and due primarily to increased a-vO2 difference (pre: 10.3 ± 1.6, post: 11.0 ± 1.7; p = 0.02). IKE training improved vasodilation and functional capacity in patients with HFpEF. Exercise interventions aimed at increasing peripheral oxidative capacity may be effective therapeutic options for HFpEF patients.
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Affiliation(s)
- Christopher M. Hearon
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
- University of Texas Southwestern Medical CenterDepartment of Internal MedicineDallasTexasUSA
| | - Mitchel Samels
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
| | - Katrin A. Dias
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
- University of Texas Southwestern Medical CenterDepartment of Internal MedicineDallasTexasUSA
| | - James P. MacNamara
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
- University of Texas Southwestern Medical CenterDepartment of Internal MedicineDallasTexasUSA
| | - Benjamin D. Levine
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
- University of Texas Southwestern Medical CenterDepartment of Internal MedicineDallasTexasUSA
| | - Satyam Sarma
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
- University of Texas Southwestern Medical CenterDepartment of Internal MedicineDallasTexasUSA
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15
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Narang N, Thibodeau JT, Parker WF, Grodin JL, Garg S, Tedford RJ, Levine BD, McGuire DK, Drazner MH. Comparison of Accuracy of Estimation of Cardiac Output by Thermodilution Versus the Fick Method Using Measured Oxygen Uptake. Am J Cardiol 2022; 176:58-65. [PMID: 35613956 PMCID: PMC9648100 DOI: 10.1016/j.amjcard.2022.04.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/24/2022] [Accepted: 04/08/2022] [Indexed: 11/18/2022]
Abstract
The thermodilution (TD) method is routinely used for the estimation of cardiac output (Q̇C). However, its accuracy, compared with the gold-standard Fick method, where systemic oxygen uptake (V̇O2) is directly measured, and Q̇C calculated from V̇O2 and the arterio-venous oxygen difference ("direct" Fick), has not been well validated. The present study determined the agreement between TD and Fick methods in consecutive patients who underwent pulmonary artery catheterization for a broad range of clinical conditions. This is a subanalysis of a previous study comparing the indirect versus Fick method based on a prospective, consecutive patient registry of 253 patients who underwent pulmonary artery catheterization for clinical indications at a single center between 1999 and 2005. We included patients that had an estimation of Q̇C both by the Fick method using measured V̇O2 by exhaled gas analyses from timed Douglas bag collections and by TD. Cardiac index was classified as low when ≤2.2 L/min/m2 or normal when >2.2 L/min/m2. The median (25th, 75th percentile) age of the cohort was 59 (50,67) years, and 50% were female. A total of 43.5% had normal left ventricular function by ventriculography, and 25.7% had ischemic heart disease. Median overall Fick and TD Q̇C were 4.4 (3.5, 5.5) and 4.3 (3.7, 5.2) L/min, respectively (p = 0.04). The median absolute percent error between Fick and TD Q̇C was 17.5 (7.7, 28.4)%, with a typical error of 0.88 L/min (95% confidence interval [CI] 0.82 to 0.95). Median absolute percent error was comparable in the low (n = 118) and normal Q̇CI (n = 135) groups (16.9% vs 18.9%, respectively, p = 0.88). typical error was 0.3 (95% CI 0.27 to 0.33) and 0.49 (95% CI 0.45 to 0.55) L/min/m2 in that comparison. Percent error >25% between Fick and TD Q̇C was observed in over 30% of patients. Overall, Fick and TD Q̇C modestly correlated (Rs = 0.64, p <0.001), with a nondirectional error introduced by TD Q̇C [mean bias of 0.21 (-2.2, 2.7) L/min]. There was poor agreement between TD and the gold-standard Fick method, highlighting the limitations of making clinical decisions based on TD.
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Affiliation(s)
- Nikhil Narang
- Advocate Heart Institute, Advocate Christ Medical Center, Oak Lawn, Illinois; Division of Cardiology, Department of Medicine, University of Illinois-Chicago, Chicago, Illinois.
| | - Jennifer T Thibodeau
- Division of Cardiology, Department of Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - William F Parker
- Section of Pulmonary and Critical Care, Department of Medicine, University of Chicago, Chicago, Illinois
| | - Justin L Grodin
- Division of Cardiology, Department of Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Sonia Garg
- Division of Cardiology, Department of Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Ryan J Tedford
- Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Benjamin D Levine
- Division of Cardiology, Department of Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas
| | - Darren K McGuire
- Division of Cardiology, Department of Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Parkland Health and Hospital System, Dallas, Texas
| | - Mark H Drazner
- Division of Cardiology, Department of Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
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Zhou X, Zhao G, Liu J, Zhou Y, Yan X, Li Z, Ma W, Jia S. Fiber pigtailed DFB laser-based optical feedback cavity enhanced absorption spectroscopy with a fiber-coupled EOM for phase correction. OPTICS EXPRESS 2022; 30:6332-6340. [PMID: 35209573 DOI: 10.1364/oe.449938] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
A novel technique for performing fiber pigtailed DFB laser and linear Fabry-Pérot cavity based optical feedback cavity enhanced absorption spectroscopy (OF-CEAS) is proposed. A fiber-coupled electro-optic modulator (f-EOM) with x-cut y-propagation LiNbO3 waveguide is employed, instead of PZT used in traditional OF-CEAS, to correct the feedback phase, which improves the compactness and applicability of OF-CEAS. Through the efficient and real-time control of the feedback phase by actively changing the input voltage of the f-EOM, a good long-term stability of the signal has been achieved. Consequently, a detection sensitivity down to 7.8×10-10 cm-1, better than the previous by PZT based OF-CEAS, has been achieved over the integration time of 200 s, even by use of a cavity with moderate finesse of 2850.
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Hieda M, Sarma S, Hearon CM, MacNamara JP, Dias KA, Samels M, Palmer D, Livingston S, Morris M, Levine BD. One-Year Committed Exercise Training Reverses Abnormal Left Ventricular Myocardial Stiffness in Patients With Stage B Heart Failure With Preserved Ejection Fraction. Circulation 2021; 144:934-946. [PMID: 34543068 DOI: 10.1161/circulationaha.121.054117] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Individuals with left ventricular (LV) hypertrophy and elevated cardiac biomarkers in middle age are at increased risk for the development of heart failure with preserved ejection fraction. Prolonged exercise training reverses the LV stiffening associated with healthy but sedentary aging; however, whether it can also normalize LV myocardial stiffness in patients at high risk for heart failure with preserved ejection fraction is unknown. In a prospective, randomized controlled trial, we hypothesized that 1-year prolonged exercise training would reduce LV myocardial stiffness in patients with LV hypertrophy. METHODS Forty-six patients with LV hypertrophy (LV septum >11 mm) and elevated cardiac biomarkers (N-terminal pro-B-type natriuretic peptide [>40 pg/mL] or high-sensitivity troponin T [>0.6 pg/mL]) were randomly assigned to either 1 year of high-intensity exercise training (n=30) or attention control (n=16). Right-heart catheterization and 3-dimensional echocardiography were performed while preload was manipulated using both lower body negative pressure and rapid saline infusion to define the LV end-diastolic pressure-volume relationship. A constant representing LV myocardial stiffness was calculated from the following: P=S×[Exp {a (V-V0)}-1], where "P" is transmural pressure (pulmonary capillary wedge pressure - right atrial pressure), "S" is the pressure asymptote of the curve, "V" is the LV end-diastolic volume index, "V0" is equilibrium volume, and "a" is the constant that characterizes LV myocardial stiffness. RESULTS Thirty-one participants (exercise group [n=20]: 54±6 years, 65% male; and controls (n=11): 51±6 years, 55% male) completed the study. One year of exercise training increased max by 21% (baseline 26.0±5.3 to 1 year later 31.3±5.8 mL·min-1·kg-1, P<0.0001, interaction P=0.0004), whereas there was no significant change in max in controls (baseline 24.6±3.4 to 1 year later 24.2±4.1 mL·min-1·kg-1, P=0.986). LV myocardial stiffness was reduced (right and downward shift in the end-diastolic pressure-volume relationship; LV myocardial stiffness: baseline 0.062±0.020 to 1 year later 0.031±0.009), whereas there was no significant change in controls (baseline 0.061±0.033 to 1 year later 0.066±0.031, interaction P=0.001). CONCLUSIONS In patients with LV hypertrophy and elevated cardiac biomarkers (stage B heart failure with preserved ejection fraction), 1 year of exercise training reduced LV myocardial stiffness. Thus, exercise training may provide protection against the future risk of heart failure with preserved ejection fraction in such patients. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03476785.
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Affiliation(s)
- Michinari Hieda
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.H., S.S., C.M.H., J.P.M., K.A.D., M.S., D.P., S.L., M.M., B.D.L.).,The University of Texas Southwestern Medical Center, Dallas (M.H., S.S., C.M.H., J.P.M., B.D.L.).,Kyushu University, School of Medicine, Fukuoka, Japan (M.H.)
| | - Satyam Sarma
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.H., S.S., C.M.H., J.P.M., K.A.D., M.S., D.P., S.L., M.M., B.D.L.).,The University of Texas Southwestern Medical Center, Dallas (M.H., S.S., C.M.H., J.P.M., B.D.L.)
| | - Christopher M Hearon
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.H., S.S., C.M.H., J.P.M., K.A.D., M.S., D.P., S.L., M.M., B.D.L.).,The University of Texas Southwestern Medical Center, Dallas (M.H., S.S., C.M.H., J.P.M., B.D.L.)
| | - James P MacNamara
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.H., S.S., C.M.H., J.P.M., K.A.D., M.S., D.P., S.L., M.M., B.D.L.).,The University of Texas Southwestern Medical Center, Dallas (M.H., S.S., C.M.H., J.P.M., B.D.L.)
| | - Katrin A Dias
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.H., S.S., C.M.H., J.P.M., K.A.D., M.S., D.P., S.L., M.M., B.D.L.)
| | - Mitchel Samels
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.H., S.S., C.M.H., J.P.M., K.A.D., M.S., D.P., S.L., M.M., B.D.L.)
| | - Dean Palmer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.H., S.S., C.M.H., J.P.M., K.A.D., M.S., D.P., S.L., M.M., B.D.L.)
| | - Sheryl Livingston
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.H., S.S., C.M.H., J.P.M., K.A.D., M.S., D.P., S.L., M.M., B.D.L.)
| | - Margot Morris
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.H., S.S., C.M.H., J.P.M., K.A.D., M.S., D.P., S.L., M.M., B.D.L.)
| | - Benjamin D Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.H., S.S., C.M.H., J.P.M., K.A.D., M.S., D.P., S.L., M.M., B.D.L.).,The University of Texas Southwestern Medical Center, Dallas (M.H., S.S., C.M.H., J.P.M., B.D.L.)
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Sarma S, Howden E, Lawley J, Samels M, Levine BD. Central Command and the Regulation of Exercise Heart Rate Response in Heart Failure With Preserved Ejection Fraction. Circulation 2020; 143:783-789. [PMID: 33205661 DOI: 10.1161/circulationaha.120.048338] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Chronotropic incompetence is common in heart failure with preserved ejection fraction (HFpEF) and is linked to impaired aerobic capacity. Whether upstream autonomic signaling pathways responsible for raising exercise heart rate are impaired in HFpEF is unknown. We investigated the integrity of central command and muscle metaboreceptor function, 2 predominant mechanisms responsible for exertional increases in heart rate, in patients with HFpEF and senior controls. METHODS Fourteen healthy senior controls (7 men, 7 women) and 20 carefully screened patients with HFpEF (8 men, 12 women) underwent cardiopulmonary exercise testing (peak Vo2) and static handgrip exercise at 40% of maximal voluntary contraction to fatigue with postexercise circulatory arrest for 2 minutes to assess central command and metaboreceptor function, respectively. RESULTS Peak Vo2 (13.1±3.4 versus 22.7±4.0 mL/kg/min; P<0.001) and heart rate (122±20 versus 155±14 bpm; P<0.001) were lower in patients with HFpEF than senior controls. There were no significant differences in peak heart rate response during static handgrip between groups (patients with HFpEF versus controls: 90±13 versus 93±10 bpm; P=0.49). Metaboreceptor function, defined as mean arterial blood pressure at the end of postexercise circulatory arrest, was not significantly different between groups. CONCLUSIONS Central command (vagally mediated) and metaboreceptor function (sympathetically mediated) in patients with HFpEF were not different from those in healthy senior controls despite significantly lower peak whole-body exercise heart rates. These results demonstrate key reflex autonomic pathways regulating exercise heart rate responsiveness are intact in HFpEF.
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Affiliation(s)
- Satyam Sarma
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (S.S., M.S., B.D.L.).,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas (S.S., B.D.L.)
| | - Erin Howden
- Baker Heart and Diabetes Institute, Melbourne, Australia (E.H.)
| | - Justin Lawley
- Department of Sport Science, University of Innsbruck, Austria (J.L.)
| | - Mitchel Samels
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (S.S., M.S., B.D.L.)
| | - Benjamin D Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas (S.S., M.S., B.D.L.).,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas (S.S., B.D.L.)
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Sarma S, MacNamara J, Livingston S, Samels M, Haykowsky MJ, Berry J, Levine BD. Impact of severe obesity on exercise performance in heart failure with preserved ejection fraction. Physiol Rep 2020; 8:e14634. [PMID: 33207080 PMCID: PMC7673482 DOI: 10.14814/phy2.14634] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 10/12/2020] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Obesity plays an important role in functional impairment in HFpEF. The mechanisms underlying decreased functional capacity in obese HFpEF are not clear. We assessed the cardiac and peripheral determinants of exercise performance in HFpEF patients with class 2 obesity in the upright position, representative of posture when performing functional activities. METHODS AND RESULTS Thirty-two HFpEF patients were divided into two groups by presence of class 2 obesity (C2, BMI ≥ 35 kg/m2 , n = 14) and non-C2 (BMI < 35 kg/m2 , n = 18). Participants performed a bout of submaximal exercise followed by incremental stages of treadmill exercise to determine peak aerobic power (peak VO2 ). Peak VO2 and Ve/VCO2 were measured using Douglas bags while cardiac output (Qc) and stroke volume (SV) were measured by acetylene rebreathing. The C2 group were younger than the non-C2 group (67 ± 6 versus 73 ± 6 years; p = .009). Comorbid condition burden was similar between groups. Peak VO2 indexed to body mass was not significantly different between groups. Absolute peak VO2 was higher in the C2 group secondary to a larger peak Qc (14.3 versus 11.0 L/min; p = .012). SV reserve was also higher in the C2 group (72 versus 49%; p = .038). CONCLUSION HFpEF patients with severe obesity had similar cardiorespiratory fitness compared to patients with lower BMI with similar comorbidity burden. Absolute VO2 was actually higher in the severely obese driven by larger Qc and SV reserve arguing against significant effects from obesity per se on aerobic performance. The presence of a larger "cardiac engine" may offer potential for fat-loss strategies to improve impairments in functional capacity in obese patients with HFpEF.
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Affiliation(s)
- Satyam Sarma
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTXUSA
- Department of Internal MedicineUniversity of Texas Southwestern Medical Center DallasDallasTXUSA
| | - James MacNamara
- Department of Internal MedicineUniversity of Texas Southwestern Medical Center DallasDallasTXUSA
| | - Sheryl Livingston
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTXUSA
| | - Mitchel Samels
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTXUSA
| | | | - Jarett Berry
- Department of Internal MedicineUniversity of Texas Southwestern Medical Center DallasDallasTXUSA
| | - Benjamin D. Levine
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTXUSA
- Department of Internal MedicineUniversity of Texas Southwestern Medical Center DallasDallasTXUSA
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Hardin EA, Stoller D, Lawley J, Howden EJ, Hieda M, Pawelczyk J, Jarvis S, Prisk K, Sarma S, Levine BD. Noninvasive Assessment of Cardiac Output: Accuracy and Precision of the Closed-Circuit Acetylene Rebreathing Technique for Cardiac Output Measurement. J Am Heart Assoc 2020; 9:e015794. [PMID: 32851906 PMCID: PMC7660774 DOI: 10.1161/jaha.120.015794] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Background Accurate assessment of cardiac output is critical to the diagnosis and management of various cardiac disease states; however, clinical standards of direct Fick and thermodilution are invasive. Noninvasive alternatives, such as closed‐circuit acetylene (C2H2) rebreathing, warrant validation. Methods and Results We analyzed 10 clinical studies and all available cardiopulmonary stress tests performed in our laboratory that included a rebreathing method and direct Fick or thermodilution. Studies included healthy individuals and patients with clinical disease. Simultaneous cardiac output measurements were obtained under normovolemic, hypovolemic, and hypervolemic conditions, along with submaximal and maximal exercise. A total of 3198 measurements in 519 patients were analyzed (mean age, 59 years; 48% women). The C2H2 method was more precise than thermodilution in healthy individuals with half the typical error (TE; 0.34 L/min [r=0.92] and coefficient of variation, 7.2%) versus thermodilution (TE=0.67 [r=0.70] and coefficient of variation, 13.2%). In healthy individuals during supine rest and upright exercise, C2H2 correlated well with thermodilution (supine: r=0.84, TE=1.02; exercise: r=0.82, TE=2.36). In patients with clinical disease during supine rest, C2H2 correlated with thermodilution (r=0.85, TE=1.43). C2H2 was similar to thermodilution and nitrous oxide (N2O) rebreathing technique compared with Fick in healthy adults (C2H2 rest: r=0.85, TE=0.84; C2H2 exercise: r=0.87, TE=2.39; thermodilution rest: r=0.72, TE=1.11; thermodilution exercise: r=0.73, TE=2.87; N2O rest: r=0.82, TE=0.94; N2O exercise: r=0.84, TE=2.18). The accuracy of the C2H2 and N2O methods was excellent (r=0.99, TE=0.58). Conclusions The C2H2 rebreathing method is more precise than, and as accurate as, the thermodilution method in a variety of patients, with accuracy similar to an N2O rebreathing method approved by the US Food and Drug Administration.
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Affiliation(s)
- E Ashley Hardin
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
| | - Douglas Stoller
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
| | - Justin Lawley
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
| | - Erin J Howden
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
| | - Michinari Hieda
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
| | - James Pawelczyk
- Department of Physiology Pennsylvania State University University Park and Hershey PA
| | - Sara Jarvis
- Department of Biological Sciences Northern Arizona University Flagstaff AZ
| | - Kim Prisk
- Department of Medicine University of California at San Diego La Jolla CA
| | - Satyam Sarma
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
| | - Benjamin D Levine
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
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