Nils P. Johnson et al. JCIN 2015;8:1018-1027 Patterns of Pd/Pa During Hyperemia Three major Pd/Pa response patterns of varying frequency occurred during steady intravenous adenosine infusion: “classic” (sigmoid), “humped” (sigmoid with superimposed bumps of varying height), and “unusual” (no pattern). For each observed example, the red dot marks the smart minimum FFR. The blue scale for Pd/Pa and time applies to the example tracings. Abbreviations as in Figure 1. Nils P. Johnson et al. JCIN 2015;8:1018-1027 2015 American College of Cardiology Foundation