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Impaired cardiac reserve and severely diminished skeletal muscle O2 utilization mediate exercise intolerance in Barth syndrome

Publication ,  Journal Article
Spencer, CT; Byrne, BJ; Bryant, RM; Margossian, R; Maisenbacher, M; Breitenger, P; Benni, PB; Redfearn, S; Marcus, E; Cade, WT
Published in: American Journal of Physiology-Heart and Circulatory Physiology
November 2011

Barth syndrome (BTHS) is a mitochondrial myopathy characterized by reports of exercise intolerance. We sought to determine if 1) BTHS leads to abnormalities of skeletal muscle O extraction/utilization and 2) exercise intolerance in BTHS is related to impaired O extraction/utilization, impaired cardiac function, or both. Participants with BTHS (age: 17 ± 5 yr, n = 15) and control participants (age: 13 ± 4 yr, n = 9) underwent graded exercise testing on a cycle ergometer with continuous ECG and metabolic measurements. Echocardiography was performed at rest and at peak exercise. Near-infrared spectroscopy of the vastus lateralis muscle was continuously recorded for measurements of skeletal muscle O extraction. Adjusting for age, peak O consumption (16.5 ± 4.0 vs. 39.5 ± 12.3 ml·kg·min, P < 0.001) and peak work rate (58 ± 19 vs. 166 ± 60 W, P < 0.001) were significantly lower in BTHS than control participants. The percent increase from rest to peak exercise in ejection fraction (BTHS: 3 ± 10 vs. control: 19 ± 4%, P < 0.01) was blunted in BTHS compared with control participants. The muscle tissue O saturation change from rest to peak exercise was paradoxically opposite (BTHS: 8 ± 16 vs. control: −5 ± 9, P < 0.01), and the deoxyhemoglobin change was blunted (BTHS: 0 ± 12 vs. control: 10 ± 8, P < 0.09) in BTHS compared with control participants, indicating impaired skeletal muscle extraction in BTHS. In conclusion, severe exercise intolerance in BTHS is due to both cardiac and skeletal muscle impairments that are consistent with cardiac and skeletal mitochondrial myopathy. These findings provide further insight to the pathophysiology of BTHS.

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Published In

American Journal of Physiology-Heart and Circulatory Physiology

DOI

EISSN

1522-1539

ISSN

0363-6135

Publication Date

November 2011

Volume

301

Issue

5

Start / End Page

H2122 / H2129

Publisher

American Physiological Society

Related Subject Headings

  • Cardiovascular System & Hematology
  • 1116 Medical Physiology
  • 0606 Physiology
 

Citation

APA
Chicago
ICMJE
MLA
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Spencer, C. T., Byrne, B. J., Bryant, R. M., Margossian, R., Maisenbacher, M., Breitenger, P., … Cade, W. T. (2011). Impaired cardiac reserve and severely diminished skeletal muscle O2 utilization mediate exercise intolerance in Barth syndrome. American Journal of Physiology-Heart and Circulatory Physiology, 301(5), H2122–H2129. https://doi.org/10.1152/ajpheart.00479.2010
Spencer, Carolyn T., Barry J. Byrne, Randall M. Bryant, Renee Margossian, Melissa Maisenbacher, Petar Breitenger, Paul B. Benni, Sharon Redfearn, Edward Marcus, and W Todd Cade. “Impaired cardiac reserve and severely diminished skeletal muscle O2 utilization mediate exercise intolerance in Barth syndrome.” American Journal of Physiology-Heart and Circulatory Physiology 301, no. 5 (November 2011): H2122–29. https://doi.org/10.1152/ajpheart.00479.2010.
Spencer CT, Byrne BJ, Bryant RM, Margossian R, Maisenbacher M, Breitenger P, et al. Impaired cardiac reserve and severely diminished skeletal muscle O2 utilization mediate exercise intolerance in Barth syndrome. American Journal of Physiology-Heart and Circulatory Physiology. 2011 Nov;301(5):H2122–9.
Spencer, Carolyn T., et al. “Impaired cardiac reserve and severely diminished skeletal muscle O2 utilization mediate exercise intolerance in Barth syndrome.” American Journal of Physiology-Heart and Circulatory Physiology, vol. 301, no. 5, American Physiological Society, Nov. 2011, pp. H2122–29. Crossref, doi:10.1152/ajpheart.00479.2010.
Spencer CT, Byrne BJ, Bryant RM, Margossian R, Maisenbacher M, Breitenger P, Benni PB, Redfearn S, Marcus E, Cade WT. Impaired cardiac reserve and severely diminished skeletal muscle O2 utilization mediate exercise intolerance in Barth syndrome. American Journal of Physiology-Heart and Circulatory Physiology. American Physiological Society; 2011 Nov;301(5):H2122–H2129.

Published In

American Journal of Physiology-Heart and Circulatory Physiology

DOI

EISSN

1522-1539

ISSN

0363-6135

Publication Date

November 2011

Volume

301

Issue

5

Start / End Page

H2122 / H2129

Publisher

American Physiological Society

Related Subject Headings

  • Cardiovascular System & Hematology
  • 1116 Medical Physiology
  • 0606 Physiology