VDAC1 and cardiac rhythm disease: When discussing VDAC2 as a potential drug target for cardiac arrhythmia, it should be noted that the transfer of Ca2+ from the sarcoplasmic reticulum into mitochondria is most likely a specialized role of VDAC2 in cardiomyocytes, presumably accomplished by a functional or even physical coupling to the ryanodine receptor (Min et al., 2012; Shimizu et al., 2015; Subedi et al., 2011) and might be less relevant or maybe accomplished by other VDAC isoforms in other cell types.