The heart's beat is caused by an electrical impulse that travels from the S-A, or sinoa-trial, node to the A-V, or atrioventricular, node and through the specialized heart muscle.
Means the heart is contracting. It usually means the ventricles are contracting, but it can also refer to atrial contraction.
The portion of the cardiac cycle in which the heart is relaxed.
Was this article helpful?