Fig. 2.

Xenon and antipyrine emergence and clearance in an isolated blood-perfused dog heart (weight = 91.4 g). The time scale is normalized by multiplying by F/W so the scale is the volume which has emerged divided by heart weight; e.g., at Ft/W = 2 the volume of flow which has emerged is the volume in ml of twice the heart weight in grams. Continuous lines are Xe; dashed lines are I-Ap. Upper panel: The emergence function η(t) is scaled by W/F as required for a self-consistent transformation. At the time of the vertical arrow, Ft/W = 1, the volumes V which had emerged and the flows F/W are listed in the same order as the curves cross the arrow. Note that the xenon escape is consistently higher for all times up to Ft/W = 1, and at late times the xenon washout is slower than antipyrine washout. Lower panel: Residue functions for xenon are consistently lower than those for antipyrine up until Ft/W is 3 or greater.