But for the first heartbeats the researchers found no clear pacemakers; different embryos had different cells that started beating first and they triggered the cells around them in a wave-like pattern.

但对于第一次心跳， 研究人员没有发搏器；不同胚胎有不同细胞， 它们首先开始跳动， 并以波状模式触发周围细胞。