We demonstrate here that patient-specific iPSC-CMs recapitulated consistently the hallmark electrophysiologic features of cardiomyopathic DMD patients (Finsterer and Stöllberger, 2003), In fact, mature iPSC-CMs from two hemizygous male DMD patients lacking the Dp427 isoform and a female patient heterozygous for a 5-exon deletion (Δ8–12) in the dystrophin gene have significantly reduced INa and IK1 densities, dV/dtmax and conduction velocities, as well as focal and reentrant arrhythmias. This evidence concerns the gene DMD and Duchenne muscular dystrophy.