A Na+/K+-ATPase inhibitor; cardiac glycoside metabolite of digoxin; has a binding affinity of 0.829 relative to [3H]ouabain; has an inhibitory potency of 1.07 relative to [3H]ouabain for its ATPase activity; selective for the α3β1 isoform over α1β1 and α2β1 (Kds = 31.8, 65, and 35 nM, respectively); produces a more potent inotropic response in perfused guinea pig hearts than digoxin (60 and 46% increases in inotropy, respectively)