LND 796 is an aminosteroidal derivative with positive inotropic effects similar to those of digitalis. It exhibits electrophysiological, toxic, and inotropic effects in normal and partially potassium-depolarized ventricular muscles. LND 796 requires higher concentrations than digoxin to induce the same toxic symptoms. It exhibits a concentration-dependent positive inotropic effect on guinea pig papillary muscles in normal potassium solution. In partially potassium-depolarized papillary muscles, LND 796 enhances both components of contraction and increases the amplitude of slow action potentials. The mechanism of positive inotropic action of LND 796 involves enhanced calcium entry in calcium channels and inhibition of sodium-potassium ATPase. Due to its expanded positive inotropic range, LND 796 may have potential application in the treatment of congestive heart failure.
