Table 4.

The organization of organoids depends on their sustained beating time.

Organoid Type	Visible Contractions and Relaxations	Sustained Beating Time
Cor-Oids	Day 2,3	~3 Weeks
WTS-Oids	Day 7,8	~2 Weeks
UKK-Oids	Day 12–15	~1 Week

Over 21 days of culture, the day when contractions and relaxations were recognized and the sustained beating time of each organoid type were found to be key points for determining their structural organization. Indeed, contractions and relaxations over time stimulate the formation of defined cardiac-like structures.