 Atrial reservoir flow component

The atrial reservoir flow component is blood entering the left atrium during ventricular systole and leaving through the mitral valve in the following ventricular diastole. This parcel-based category in atrial flow component analysis specifies both arrival and departure phases.^[ref]

Its definition explains the storage interpretation of atrial reservoir function. In an idealized closed-outlet interval, the left atrium's volume balance iswhere $Q_{\mathrm{PV}}$ is total net inflow from the pulmonary veins. A stipulated constant 50 mL/s for 0.3 s increases atrial volume by 15 mL. This balance describes storage during that interval. To label all 15 mL as atrial reservoir flow component, a parcel record must additionally show the prescribed subsequent exit.

For example, imagine that the stored 15 mL comprises 12 mL that leaves in the following ventricular diastole and 3 mL that remains beyond it. The volume increase is still 15 mL, but the qualifying atrial reservoir flow component from those arrivals is 12 mL. Conversely, older blood can leave during the same filling phase without having entered during the immediately preceding ventricular systole.

A maximum-minus-minimum atrial volume is therefore not an automatic census of this category. Chamber volume measures how much is inside at a given time; pathlines identify which represented blood is inside and where it goes. The primary study combined moving anatomy from computed tomography, computational fluid dynamics and numerical pathlines rather than directly measuring each parcel's velocity with the anatomical scanner.^[ref] These complementary observations connect a visible chamber motion to a specific transport question.