Extrinsic control:
Release of the following substances from the sympathetic and parasympathetic branches of the autonomic nervous system, effect chronotropicity:
These actions are mediated through cardiopulmonary receptors, such as the carotid sinus (aortic) baroreceptors, carotid (aortic) body chemoreceptors,
central chemoreceptors, venae cavae/atrial volume receptors (Bainbridge Reflex), and the ventricular volume receptors.
Intrinsic control:
Environment - ischemia, stretch, K+, Ca++, temperature