Fig. 3

Global gene expression pathway analysis on patients without myocardial perfusion defects (n = 54). Red bars predict an overall increase in the activity of the pathway (activation) while blue bars indicate a prediction of an overall decrease in activity (deactivation/inhibition). White bars are those with a z-score which is zero or very close to zero. The overall activation/inhibition (deactivation) states of the pathways are predicted based on a Z-score algorithm. Z-score gives a statistical measure of the relationship of up and downregulated gene transcripts in the microarray data set with-respect-to a particular pathway. This Z-score is used to mathematically compare the microarray data set with the canonical pathway patterns. A pathway is predicted as activated or inhibited by comparing the expected pattern (up/downregulation of key genes in the pathway) if the pathway is activated against the actual pattern (up/downregulated key genes) in the microarray data set. If the actual pattern matches the expected pattern, the Z-score is positive (Z-score > ~2 = activated pathway) otherwise negative (Z-score <2 = inhibited pathway)