CAV3 and hydrops fetalis: To investigate whether the graded changes in t‐tubule structure observed in HTY and HF myocytes could be attributable to graded changes in expression of Jph2, Bin1 and/or Cav3, all of which have been implicated in t‐tubule formation and maintenance (Caldwell et al., 2014; Ziman, Gómez‐Viquez, Bloch, & Lederer, 2010) and have been reported to change in HF (Frisk et al., 2016; Reynolds et al., 2016), we investigated the expression of these proteins in each group.