Regulation of performance of the heart.
D001696:Biomechanical Phenomena; D001775:Blood Circulation / Q000502:physiology*; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology; D011984:Sensory Receptor Cells / Q000502:physiology; D013564:Sympathetic Nervous System / Q000502:physiology