Changes in IWS, peak systolic WS, and end diastolic WS with dobutamine stimulation. A: IWS changes with incremental dobutamine stress. The IWS were comparable between MI (n = 5) and sham group (n = 5) at the baseline. However, IWS in MI hearts increased significantly with dobutamine stimulation, whereas there was no noticeable increase of IWS in the sham hearts. ms: millisecond. Changes in peak systolic WS (B) and end diastolic WS (C) with incremental dobutamine stress after small MI. Both peak systolic WS and end diastolic WS in MI hearts were significantly higher than those in sham hearts with dobutamine stimulation. * p < 0.05 vs. sham, # p < 0.05 vs. 0 mcg/kg/min, § < 0.05 vs. 5 mcg/kg/min.