English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Inert gas measurements of flow per unit weight (F/W) incorporating even saturation of heterogeneously perfused areas and two–decade resolution of coronary venous desaturation curves have been compared with radioactive microsphere measurements of F/W in closed–chest dogs with modest heterogeneity of F/W. Coefficients of variation for microsphere measurements in 96 left ventricular segments revealed global heterogeneity of F/W, of similar degree, in dogs with and without an abdominal aortocaval fistula (0.18 ±4- 0.07 vs 0.15 ± 0.04; p > 0.3). Endocardial–epicardial flow ratios were lower in the fistula dogs (0.77 ± 0.11 vs 1.05 ⊥ 0.08; p < 0.01), reflecting transmural as well as nontransmural heterogeneity of F/W. Inert gas measurements of average F/W, derived from the Kety–Schmidt equation using dissolved hydrogen (H2) as tracer, agreed within i 20% of average microsphere F/W in 18 of 20 comparisons in fistula and nonfistula dogs. Semilogarithmically plotted H2 desaturation data were curvilinear in both settings, but arbitrarily derived ‘slow–compartment’ H2 F/W agreed with average microsphere endocardial F/W only in the fistula dogs. We conclude that 1) methodologically adequate inert gas measurements give accurate values for average F/W in the presence of moderate heterogeneity of perfusion; and 2) although the presence of heterogeneous perfusion can be appreciated from the shape of inert gas desaturation curves, compartmental analyses of curves cannot ordinarily be interpreted in a specific transmural or other spatial sense.

Inert gas measurements of myocardial perfusion in the presence of heterogeneous flow documented by microspheres.