UMAP visualizations demonstrated elevated expression of troponin genes TNNT2 (Figure 4A–D), TNNI3 (Figure 4E–H), and TTN (Figure 4I–L) in cardiomyocytes of TOF, DCM, HCM, HF-HLHS, and Neo-HLHS compared to the donor control (Supplementary Figure S2A–G). Here, TNNI3 is linked to hydrops fetalis.