Breathing manoeuvre-dependent changes in myocardial oxygenation in healthy humans.

Günsch, Dominik; Fischer, Kady Anne; Flewitt, Jacqueline A; Yu, Janelle; Lukic, Ryan; Friedrich, Julian A; Friedrich, Matthias G (2014). Breathing manoeuvre-dependent changes in myocardial oxygenation in healthy humans. European heart journal - cardiovascular imaging, 15(4), pp. 409-414. Oxford University Press 10.1093/ehjci/jet171

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AIMS CO₂ is an intrinsic vasodilator for cerebral and myocardial blood vessels. Myocardial vasodilation without a parallel increase of the oxygen demand leads to changes in myocardial oxygenation. Because apnoea and hyperventilation modify blood CO₂, we hypothesized that voluntary breathing manoeuvres induce changes in myocardial oxygenation that can be measured by oxygenation-sensitive cardiovascular magnetic resonance (CMR). METHODS AND RESULTS Fourteen healthy volunteers were studied. Eight performed free long breath-hold as well as a 1- and 2-min hyperventilation, whereas six aquatic athletes were studied during a 60-s breath-hold and a free long breath-hold. Signal intensity (SI) changes in T₂*-weighted, steady-state free precession, gradient echo images at 1.5 T were monitored during breathing manoeuvres and compared with changes in capillary blood gases. Breath-holds lasted for 35, 58 and 117 s, and hyperventilation for 60 and 120 s. As expected, capillary pCO₂ decreased significantly during hyperventilation. Capillary pO₂ decreased significantly during the 117-s breath-hold. The breath-holds led to a SI decrease (deoxygenation) in the left ventricular blood pool, while the SI of the myocardium increased by 8.2% (P = 0.04), consistent with an increase in myocardial oxygenation. In contrast, hyperventilation for 120 s, however, resulted in a significant 7.5% decrease in myocardial SI/oxygenation (P = 0.02). Change in capillary pCO₂ was the only independently correlated variable predicting myocardial oxygenation changes during breathing manoeuvres (r = 0.58, P < 0.01). CONCLUSION In healthy individuals, breathing manoeuvres lead to changes in myocardial oxygenation, which appear to be mediated by CO₂. These changes can be monitored in vivo by oxygenation-sensitive CMR and thus, may have value as a diagnostic tool.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Intensive Care, Emergency Medicine and Anaesthesiology (DINA) > Clinic and Policlinic for Anaesthesiology and Pain Therapy

UniBE Contributor:

Günsch, Dominik and Fischer, Kady Anne

Subjects:

600 Technology > 610 Medicine & health

ISSN:

2047-2412

Publisher:

Oxford University Press

Language:

English

Submitter:

Jeannie Wurz

Date Deposited:

22 May 2015 14:36

Last Modified:

23 Jan 2018 12:15

Publisher DOI:

10.1093/ehjci/jet171

PubMed ID:

24078154

Uncontrolled Keywords:

BOLD-sensitive MRI; T2*-weighted imaging; apnoea; carbon dioxide; hyperventilation; vasodilation

BORIS DOI:

10.7892/boris.69121

URI:

https://boris.unibe.ch/id/eprint/69121

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