There are two type of cardiac calcium channel current, both are inward current: (1) L-type Ca 2+ channel current(I ca-L ),plays a major role in determining myocyte action potential plateau characteristics as well as initiating the myocyte excitation-contraction coupling; (2) T-type Ca 2+ channel current(I ca-T ), probably plays an important role in pacemaker activity. The alterations of L-type calcium channel abundance and function in cardiac hypertrophy and heart failure are determined by the the species difference, especially by the stage of the disease process and the degree of the disease. Both abundance and function of L-type calcium channel decrease in severe hypertrophy and heart failure.
