We decided to use the substrain “RJj” for three reasons: (1) C57BL/6JRj mice, in contrary to the 129 background animals, present an RR interval more stable over the life span of the animals, a parameter altered in Trpm4 knockdown mouse models (Vignier et al., 2019), (2) those mice are protected from overweigh which can influence, if append, the interpretation of the data (Siersbaek et al., 2020) and (3) no cardiac hypertrophy has been, till today, descript concerning thus substrain in contrary to the C57BL/6N (Kiper et al., 2013; Moreth et al., 2014). Here, TRPM4 is linked to cardiac hypertrophy.