Figure 4

Cyclic myocardial perfusion variation over the cardiac cycle. A) Mean MBF within the group of seven healthy rats are reported as a function of the normalized cardiac cycle. These are shown at rest (grey diamonds) and during adenosine-induced stress (black triangles). For clarity, a six orders polynomial regression was used to fit the data. Error bars correspond to the standard deviation within the group for each temporal bin. Minimum MBF was found to be at ES for both physiological states. Maximum MBF was found to be at ED at rest and sooner than ED during stress. B) MPR values are given as free ratios of stress and rest MBF. MPR behavior (black squares) was found reversed compared to MBF variation, with first an initial increase during systole until a maximum at ES. This maximum value was conserved during most of diastole with a minimum at ED.