The active end product of the renin-angiotensin system, angiotensin II (Ang
II), through the activation of specific Ang II receptors, regulates cardia
c contractility, cell coupling, and impulse propagation and is involved in
cardiac remodeling, growth, and apoptosis. We review these subjects, as wel
l as the second messengers that are involved, and the synthesis of Ang II i
n the heart under normal and pathological conditions. Finally, we discuss t
he possibility that there is an intracrine renin-angiotensin system in the
heart that plays a role in the control of cell communication and inward Ca2
+ current.