Pretreatment with KN-93 increases the arrhythmia threshold during NE infusion. A) ECG traces from paired studies in a HF rabbit during pretreatment with saline (Veh) or KN-93. With Veh, VT was induced during infusion of NE at 3.13 μg/kg/min. With KN-93, VT was not induced until the maximal dose, 25 μg/kg/min. B) Paired observations of individual (small symbols) and median (large symbols) values of the NE dose threshold for the induction of VT with pretreatment of saline (Vehicle) or KN-93 in naïve (n = 8, left) and HF (n = 7, right) rabbits. *p < 0.05 KN-93 vs Vehicle