Although variants in TRPM4 have been associated with arrythmias [18,32], our case, with the p.Arg905Trp variant, demonstrated recurrent EHI that was found to be complicated by syncope and which was diagnosed as MH susceptible (Table S4), with no variants in MH candidate genes [9,10,11,12]. This evidence concerns the gene TRPM4 and cardiac arrhythmia.