A single heart cell was extracted from a live mouse and observed under a microscope. At first, the single heart cell pulsated evenly, but then experienced arrhythmia. The cell soon died of a micro-heart attack.

As a follow-up experiment, the researchers used a pair of heart cells and observed the same pattern. During the fibrillation phase, the researches started moving the heart cells together, and at a certain proximity, the cells stopped fibrillating and synchronized into a normal pulse rhythm without touching.

In this video, Frederick Tamagi explores how researchers created a two-cell microscopic heart.