Fig. 9.

Estimates of flow and V_SV obtained by simultaneously optimizing flow, V_SV, and V_LV to fit pseudodata containing a realistic level of random noise (similar to that in Fig. 8). Pseudodata were generated using using normal flow heterogeneity and 15 combinations of flow and V_SV covering physiological range. True values of flow and V_SV are indicated by 15 intersections of lines. True value of V_LV was constant at 0.028 ml/g. Ten independent realizations of random uniform noise were added to each set of pseudodata. Each symbol represents optimized parameters obtained from a single model fit. There was negligible systematic error in parameter estimates when model included normal flow heterogeneity; i.e., for all ○, true values are at nearest intersection. However, systematic underestimates of flow and V_SV were observed when heterogeneity was not included in model; i.e., for all ◆, true values are at nearest intersection to right.