The American Journal of Physiology-Heart and Circulatory Physiology publishes original investigations, reviews and perspectives on the physiology of the heart, vasculature, and lymphatics. These articles include experimental and theoretical studies of cardiovascular function at all levels of organization ranging from the intact and integrative animal and organ function to the cellular, subcellular, and molecular levels. The journal embraces new descriptions of these functions and their control systems, as well as their basis in biochemistry, biophysics, genetics, and cell biology. Preference is given to research that provides significant new mechanistic physiological insights that determine the performance of the normal and abnormal heart and circulation.