Figure 7. Prevention of RIRR and arrhythmias by EUK-134.

A, average normalized DHE fluorescence of control (blue) and EUK-134 (50 μm, red)-treated hearts to perfusion with 200 μm H₂O₂ for 10 min. In the treatment group, perfusion with the synthetic superoxide dismutase/catalase mimetic prevented the rise in ROS levels. EUK-134 perfusion was introduced 10 min prior to the H₂O₂ challenge and maintained throughout the entire protocol. B, prevention of RIRR by EUK-134 was associated with full protection against H₂O₂-mediated arrhythmias. C, average normalized left ventricular cavity pressure measurements following H₂O₂ challenge as compared to baseline indicate significant preservation of contractility in EUK-134-treated hearts compared to controls. D, representative traces of left ventricular cavity pressure recordings measured in control and EUK-134-treated hearts indicating preservation of contractility in EUK-134-treated but not control hearts following challenge with the RIRR protocol.