TNNT2 and hydrops fetalis: Subsequently, we established a 24‐h hypoxia‐induced cardiac organoid model of HF in vitro, with validation conducted through morphological assessment (Figure S1A) and analysis of HF markers including cell viability, lactate dehydrogenase (LDH), cardiac troponin T (cTnT), and N‐terminal pro‐B‐type Natriuretic peptide (NT‐proBNP) (Figure 1A).