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Intracardiac light catheter for rapid scanning transmural absorbance spectroscopy of perfused myocardium: measurement of myoglobin oxygenation and mitochondria redox state.

Authors :
Femnou, Armel N.
Kuzmiak-Glancy, Sarah
Covian, Raul
Giles, Abigail V.
Kay, Matthew W.
Balaban, Robert S.
Source :
American Journal of Physiology: Heart & Circulatory Physiology. Dec2017, Vol. 313 Issue 6, pH1199-H1208. 10p.
Publication Year :
2017

Abstract

Absorbance spectroscopy of intrinsic cardiac chromophores provides nondestructive assessment of cytosolic oxygenation and mitochondria redox state. Isolated perfused heart spectroscopy is usually conducted by collecting reflected light from the heart surface, which represents a combination of surface scattering events and light that traversed portions of the myocardium. Reflectance spectroscopy with complex surface scattering effects in the beating heart leads to difficulty in quantitating chromophore absorbance. In this study, surface scattering was minimized and transmural path length optimized by placing a light source within the left ventricular chamber while monitoring transmurally transmitted light at the epicardial surface. The customdesigned intrachamber light catheter was a flexible coaxial cable (2.42-Fr) terminated with an encapsulated side-firing LED of 1.8 x 0.8 mm, altogether similar in size to a Millar pressure catheter. The LED catheter had minimal impact on aortic flow and heart rate in Langendorff perfusion and did not impact stability of the left ventricule of the working heart. Changes in transmural absorbance spectra were deconvoluted using a library of chromophore reference spectra to quantify the relative contribution of specific chromophores to the changes in measured absorbance. This broad-band spectral deconvolution approach eliminated errors that may result from simple dualwavelength absorbance intensity. The myoglobin oxygenation level was only 82.2 ± 3.0%, whereas cytochrome c and cytochrome a + a3 were 13.3 ± 1.4% and 12.6 ± 2.2% reduced, respectively, in the Langendorff-perfused heart. The intracardiac illumination strategy permits transmural optical absorbance spectroscopy in perfused hearts, which provides a noninvasive real-time monitor of cytosolic oxygenation and mitochondria redox state. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
03636135
Volume :
313
Issue :
6
Database :
Academic Search Index
Journal :
American Journal of Physiology: Heart & Circulatory Physiology
Publication Type :
Academic Journal
Accession number :
133098115
Full Text :
https://doi.org/10.1152/ajpheart.00306.2017