SRC and hydrops fetalis: Furthermore, transmission electron microscope images showed that HF cardiomyocytes had significantly more abnormally-shaped mitochondria with poorly-defined cristae, characteristic of mitochondrial damage, compared with Con (Fig. 7C, D), though damaged mitochondria counts were reduced towards Con among HF + HIIT + Src-shRNA and HF + Metrnl (Fig. 7D).