The role of the right ventricle during hypobaric hypoxic exercise

Insights from patients after the Fontan operation

Jorge A. Garcia, Susan B. McMinn, Julie H. Zuckerman, David E Fixler, Benjamin D Levine

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Objectives: The principal objective of this study was to examine the importance of the fight ventricle for maximal systemic oxygen transport during exercise at high altitude by studying patients after the Fortan operation. Background: High-altitude-induced hypoxia causes a reduction in maximal oxygen uptake. Normal right ventricular pump function may be critical to sustain cardiac output in the face of hypoxic pulmonary vasoconstriction. We hypothesized that patients after the Fontan operation, who lack a functional subpulmonary ventricle, would have a limited exercise capacity at altitude, with an inability to increase cardiac output. Methods: We measured oxygen uptake (V̇O2, Douglas bag), cardiac output (Q̇c, C2H2 rebreathing), heart rate (HR) (ECG), blood pressure (BP) (cuff), and O2 Sat (pulse oximetry) in 11 patients aged 14.5 ± 5.2 yr (mean ± SD) at 4.7 ± 1.6 yr after surgery. Data were obtained at rest, at three submaximal steady state workrates, and at peak exercise on a cycle ergometer. All tests were performed at sea level (SL) and at simulated altitude (ALT) of 3048 m (10,000 ft, 522 torr) in a hypobaric chamber. Results: At SL, resting O2 sat was 92.6 ± 4%. At ALT, O2 sat decreased to 88.2 ± 4.6% (P < 0.05) at rest and decreased further to 80 ± 6.3% (P < 0.05) with peak exercise. At SL, V̇O2 increased from 5.1 ± 0.9 mL · kg-1 · min-1 at rest to 23.5 ± 5.3 mL · kg-1 · min-1 at peak exercise and CI (Q̇c · m-2) increased from 3.3 ± 0.7 L · m-2 to 6.2 ± 1.2 L · m-2.V̇O2 peak, 17.8 ± 4 mL · kg-1 · min-1 (P < 0.05), and CI peak, 5.0 ± 1.5 L · m-2 (P < 0.05), were both decreased at ALT. Remarkably, the relationship between Q̇c and V̇O2 was normal during submaximal exercise at both SL and ALT. However at ALT, stroke volume index (SVI, SV · m-2) decreased from 37.7 ± 8.6 mL · min-1 · m2 at rest, to 31.3 ± 8.6 mL · min-1 · m2 at peak exercise (P < 0.05), whereas it did not fall during sea level exercise. Conclusions: During submaximal exercise at altitude, right ventricular contractile function is not necessary to increase cardiac output appropriately for oxygen uptake. However, normal right ventricular pump function may be necessary to achieve maximal cardiac output during exercise with acute high altitude exposure.

Original languageEnglish (US)
Pages (from-to)269-276
Number of pages8
JournalMedicine and Science in Sports and Exercise
Volume31
Issue number2
StatePublished - 1999

Fingerprint

Fontan Procedure
Heart Ventricles
Exercise
Oceans and Seas
Cardiac Output
Right Ventricular Function
Oxygen
Altitude Sickness
Oximetry
Vasoconstriction
Stroke Volume
Electrocardiography
Heart Rate
Blood Pressure
Lung

Keywords

  • Altitude
  • Congenital heart disease
  • Exercise
  • Fontan
  • Hypoxia
  • Right ventricle

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Physical Therapy, Sports Therapy and Rehabilitation
  • Orthopedics and Sports Medicine

Cite this

The role of the right ventricle during hypobaric hypoxic exercise : Insights from patients after the Fontan operation. / Garcia, Jorge A.; McMinn, Susan B.; Zuckerman, Julie H.; Fixler, David E; Levine, Benjamin D.

In: Medicine and Science in Sports and Exercise, Vol. 31, No. 2, 1999, p. 269-276.

Research output: Contribution to journalArticle

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abstract = "Objectives: The principal objective of this study was to examine the importance of the fight ventricle for maximal systemic oxygen transport during exercise at high altitude by studying patients after the Fortan operation. Background: High-altitude-induced hypoxia causes a reduction in maximal oxygen uptake. Normal right ventricular pump function may be critical to sustain cardiac output in the face of hypoxic pulmonary vasoconstriction. We hypothesized that patients after the Fontan operation, who lack a functional subpulmonary ventricle, would have a limited exercise capacity at altitude, with an inability to increase cardiac output. Methods: We measured oxygen uptake (V̇O2, Douglas bag), cardiac output (Q̇c, C2H2 rebreathing), heart rate (HR) (ECG), blood pressure (BP) (cuff), and O2 Sat (pulse oximetry) in 11 patients aged 14.5 ± 5.2 yr (mean ± SD) at 4.7 ± 1.6 yr after surgery. Data were obtained at rest, at three submaximal steady state workrates, and at peak exercise on a cycle ergometer. All tests were performed at sea level (SL) and at simulated altitude (ALT) of 3048 m (10,000 ft, 522 torr) in a hypobaric chamber. Results: At SL, resting O2 sat was 92.6 ± 4{\%}. At ALT, O2 sat decreased to 88.2 ± 4.6{\%} (P < 0.05) at rest and decreased further to 80 ± 6.3{\%} (P < 0.05) with peak exercise. At SL, V̇O2 increased from 5.1 ± 0.9 mL · kg-1 · min-1 at rest to 23.5 ± 5.3 mL · kg-1 · min-1 at peak exercise and CI (Q̇c · m-2) increased from 3.3 ± 0.7 L · m-2 to 6.2 ± 1.2 L · m-2.V̇O2 peak, 17.8 ± 4 mL · kg-1 · min-1 (P < 0.05), and CI peak, 5.0 ± 1.5 L · m-2 (P < 0.05), were both decreased at ALT. Remarkably, the relationship between Q̇c and V̇O2 was normal during submaximal exercise at both SL and ALT. However at ALT, stroke volume index (SVI, SV · m-2) decreased from 37.7 ± 8.6 mL · min-1 · m2 at rest, to 31.3 ± 8.6 mL · min-1 · m2 at peak exercise (P < 0.05), whereas it did not fall during sea level exercise. Conclusions: During submaximal exercise at altitude, right ventricular contractile function is not necessary to increase cardiac output appropriately for oxygen uptake. However, normal right ventricular pump function may be necessary to achieve maximal cardiac output during exercise with acute high altitude exposure.",
keywords = "Altitude, Congenital heart disease, Exercise, Fontan, Hypoxia, Right ventricle",
author = "Garcia, {Jorge A.} and McMinn, {Susan B.} and Zuckerman, {Julie H.} and Fixler, {David E} and Levine, {Benjamin D}",
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T1 - The role of the right ventricle during hypobaric hypoxic exercise

T2 - Insights from patients after the Fontan operation

AU - Garcia, Jorge A.

AU - McMinn, Susan B.

AU - Zuckerman, Julie H.

AU - Fixler, David E

AU - Levine, Benjamin D

PY - 1999

Y1 - 1999

N2 - Objectives: The principal objective of this study was to examine the importance of the fight ventricle for maximal systemic oxygen transport during exercise at high altitude by studying patients after the Fortan operation. Background: High-altitude-induced hypoxia causes a reduction in maximal oxygen uptake. Normal right ventricular pump function may be critical to sustain cardiac output in the face of hypoxic pulmonary vasoconstriction. We hypothesized that patients after the Fontan operation, who lack a functional subpulmonary ventricle, would have a limited exercise capacity at altitude, with an inability to increase cardiac output. Methods: We measured oxygen uptake (V̇O2, Douglas bag), cardiac output (Q̇c, C2H2 rebreathing), heart rate (HR) (ECG), blood pressure (BP) (cuff), and O2 Sat (pulse oximetry) in 11 patients aged 14.5 ± 5.2 yr (mean ± SD) at 4.7 ± 1.6 yr after surgery. Data were obtained at rest, at three submaximal steady state workrates, and at peak exercise on a cycle ergometer. All tests were performed at sea level (SL) and at simulated altitude (ALT) of 3048 m (10,000 ft, 522 torr) in a hypobaric chamber. Results: At SL, resting O2 sat was 92.6 ± 4%. At ALT, O2 sat decreased to 88.2 ± 4.6% (P < 0.05) at rest and decreased further to 80 ± 6.3% (P < 0.05) with peak exercise. At SL, V̇O2 increased from 5.1 ± 0.9 mL · kg-1 · min-1 at rest to 23.5 ± 5.3 mL · kg-1 · min-1 at peak exercise and CI (Q̇c · m-2) increased from 3.3 ± 0.7 L · m-2 to 6.2 ± 1.2 L · m-2.V̇O2 peak, 17.8 ± 4 mL · kg-1 · min-1 (P < 0.05), and CI peak, 5.0 ± 1.5 L · m-2 (P < 0.05), were both decreased at ALT. Remarkably, the relationship between Q̇c and V̇O2 was normal during submaximal exercise at both SL and ALT. However at ALT, stroke volume index (SVI, SV · m-2) decreased from 37.7 ± 8.6 mL · min-1 · m2 at rest, to 31.3 ± 8.6 mL · min-1 · m2 at peak exercise (P < 0.05), whereas it did not fall during sea level exercise. Conclusions: During submaximal exercise at altitude, right ventricular contractile function is not necessary to increase cardiac output appropriately for oxygen uptake. However, normal right ventricular pump function may be necessary to achieve maximal cardiac output during exercise with acute high altitude exposure.

AB - Objectives: The principal objective of this study was to examine the importance of the fight ventricle for maximal systemic oxygen transport during exercise at high altitude by studying patients after the Fortan operation. Background: High-altitude-induced hypoxia causes a reduction in maximal oxygen uptake. Normal right ventricular pump function may be critical to sustain cardiac output in the face of hypoxic pulmonary vasoconstriction. We hypothesized that patients after the Fontan operation, who lack a functional subpulmonary ventricle, would have a limited exercise capacity at altitude, with an inability to increase cardiac output. Methods: We measured oxygen uptake (V̇O2, Douglas bag), cardiac output (Q̇c, C2H2 rebreathing), heart rate (HR) (ECG), blood pressure (BP) (cuff), and O2 Sat (pulse oximetry) in 11 patients aged 14.5 ± 5.2 yr (mean ± SD) at 4.7 ± 1.6 yr after surgery. Data were obtained at rest, at three submaximal steady state workrates, and at peak exercise on a cycle ergometer. All tests were performed at sea level (SL) and at simulated altitude (ALT) of 3048 m (10,000 ft, 522 torr) in a hypobaric chamber. Results: At SL, resting O2 sat was 92.6 ± 4%. At ALT, O2 sat decreased to 88.2 ± 4.6% (P < 0.05) at rest and decreased further to 80 ± 6.3% (P < 0.05) with peak exercise. At SL, V̇O2 increased from 5.1 ± 0.9 mL · kg-1 · min-1 at rest to 23.5 ± 5.3 mL · kg-1 · min-1 at peak exercise and CI (Q̇c · m-2) increased from 3.3 ± 0.7 L · m-2 to 6.2 ± 1.2 L · m-2.V̇O2 peak, 17.8 ± 4 mL · kg-1 · min-1 (P < 0.05), and CI peak, 5.0 ± 1.5 L · m-2 (P < 0.05), were both decreased at ALT. Remarkably, the relationship between Q̇c and V̇O2 was normal during submaximal exercise at both SL and ALT. However at ALT, stroke volume index (SVI, SV · m-2) decreased from 37.7 ± 8.6 mL · min-1 · m2 at rest, to 31.3 ± 8.6 mL · min-1 · m2 at peak exercise (P < 0.05), whereas it did not fall during sea level exercise. Conclusions: During submaximal exercise at altitude, right ventricular contractile function is not necessary to increase cardiac output appropriately for oxygen uptake. However, normal right ventricular pump function may be necessary to achieve maximal cardiac output during exercise with acute high altitude exposure.

KW - Altitude

KW - Congenital heart disease

KW - Exercise

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KW - Hypoxia

KW - Right ventricle

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