If you look at it long enough, it is a word that opens and spreads out, makes a circle of a far horizon, a word on which rain can fall and dimple or sweep across in lashing gusts and leave unperturbed, a word that is calm enough to look at, almost lulling, but also hints at holding unreckonable power."

VOA: standard.2010.08.04

So, there's a continuum of electrical connection in the heart that allows an action potential to sweep across the surface of the heart and for the heart to beat in a coordinated fashion.

所以 心脏细胞有电偶联的连结组织,以使动作电位平稳在细胞表面传递,保证心脏的协调性跳动

耶鲁公开课 - 生物医学工程探索课程节选