Show simple item record

dc.contributor.authorBoulet, Lindsey
dc.contributor.authorStembridge, Mike
dc.contributor.authorTymko, Michael
dc.contributor.authorTremblay, Joshua
dc.contributor.authorFoster, Glen
dc.date.accessioned2016-05-31T15:25:15Z
dc.date.available2016-05-31T15:25:15Z
dc.date.issued2016-08-01
dc.identifier.citationBoulet, L.M., Stembridge, M., Tymko, M.M., Tremblay, J.C. and Foster, G.E. (2016) 'The effects of graded changes in oxygen and carbon dioxide tension on coronary blood velocity independent of myocardial energy demand', American Journal of Physiology-Heart and Circulatory Physiology, 311 (2), pp. 326-336en_US
dc.identifier.issn0363-6135
dc.identifier.issn1522-1539 (ESSN)
dc.identifier.urihttp://hdl.handle.net/10369/7893
dc.descriptionThis article was published in American Journal of Physiology-Heart and Circulatory Physiology on 01 August 2016 (online), available at http://dx.doi.org/10.1152/ajpheart.00107.2016en_US
dc.description.abstractIn humans, coronary blood flow is tightly regulated by microvessels within the myocardium in order to match myocardial energy demand. However, evidence regarding inherent sensitivity of the microvessels to changes in arterial partial pressure of carbon dioxide and oxygen is conflicting due to the accompanied changes in myocardial energy requirements. This study aimed to investigate the changes in coronary blood velocity while manipulating partial pressures of end-tidal CO2 (PETCO2) and O2 (PETO2). It was hypothesized that an increase in PETCO2 (hypercapnia) or decrease in PETO2 (hypoxia) would result in a significant increase in mean blood velocity in the left anterior descending artery (LADVmean) due to an increase in both blood gases and energy demand associated with the concomitant cardiovascular response. Cardiac energy demand was assessed through non-invasive measurement of the total left ventricular mechanical energy. Healthy subjects (n=13) underwent a euoxic CO2 test (PETCO2 = -8, -4, 0, +4, and +8 mmHg from baseline) and an isocapnic hypoxia test (PETO2 = 64, 52 and 45 mmHg). LADVmean was assessed using transthoracic Doppler echocardiography. Hypercapnia evoked a 34.6 ± 8.5% (mean ± SEM; P<0.01) increase in mean LADVmean, whereas hypoxia increased LADVmean by 51.4 ± 8.8% (P<0.05). Multiple stepwise regressions revealed that both mechanical energy and changes in arterial blood gases are important contributors to the observed changes in LADVmean (P<0.01). In summary, regulation of the coronary vasculature in humans is mediated by metabolic changes within the heart and an inherent sensitivity to arterial blood gases.en_US
dc.description.sponsorshipNatural Sciences and Engineering Research Council of Canada and Canada Foundation for Innovationen_US
dc.language.isoenen_US
dc.publisherAmerican Physiological Societyen_US
dc.relation.ispartofseriesAmerican Journal of Physiology-Heart and Circulatory Physiology
dc.subjectcoronary vesselsen_US
dc.subjecthypoxiaen_US
dc.subjectCarbon dioxideen_US
dc.subjectEchocardiographyen_US
dc.subjectdynamic end-tidal forcingen_US
dc.titleThe effects of graded changes in oxygen and carbon dioxide tension on coronary blood velocity independent of myocardial energy demanden_US
dc.typeArticleen_US
dc.identifier.doihttp://dx.doi.org/10.1152/ajpheart.00107.2016
dc.date.dateAccepted2016-05-19
dc.rights.embargodate2017-05-27
dc.rights.embargoreason12 month embargo requested by publisher
rioxxterms.freetoread.startdate2017-05-27


Files in this item

Thumbnail

This item appears in the following collection(s)

Show simple item record