Cardiac myocytes are the most physically energetic cells in the body. They are highly specialized high-oxygen-content cells that house a large number of mitochondria [1]. They occupy as much as 75% of the cardiac mass, but constitute only about one third of the total cell number in the heart. Differentiated cardiac myocytes have little capacity to proliferate; however, hypertrophic growth has been shown to respond to alpha1-adrenergic stimuli via the Ras/MEK pathway [2]. All cardiac myocytes are capable of spontaneous rhythmic depolarization and repolarization of their membranes. Contraction of cardiac myocytes is myogenic, which is independent of nervous stimulation. There is a complex network of signals in cardiac myocytes regulating the rhythmic pumping of the heart [3]. Cardiac myocyte hypertrophy and apoptosis have been implicated in the loss of contractile function during heart failure. A better understanding of the cardiac signaling network will help reveal the cellular mechanisms leading to cardiac myocyte death. HCM-a from ScienCell Research Laboratories are isolated from human adult heart. HCM-a are cryopreserved after purification and delivered frozen. Each vial contains >1 x 10^6 cells in 1 ml volume. HCM-a are characterized by immunofluorescence with antibody specific to sarcomeric α-actinin. HCM-a are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast, and fungi. HCM-a are guaranteed to further culture under the conditions provided by ScienCell Research Laboratories; however, HCM-a are not recommended for expanding or long-term cultures since the cells do not proliferate in culture. Recommended Medium It is recommended to use Cardiac Myocyte Medium-serum free (CMM-sf, Cat. #6101) for culturing HCM-a in vitro.