45 year-old male with Becker muscular dystrophy (BMD), dilated cardiomyopathy (DCM) and reduced left ventricular ejection fraction (LVEF) developed ventricular tachycardia (VT), successfully treated with appropriate shocks from his cardioverter-defibrillator (ICD). Substrate ablation was planned, and although cardiac magnetic resonance (CMR) was performed, interpretation was impaired due to significative lead artifact. Epicardial access was obtained; electroanatomical (EA) mapping revealed a large area of low-amplitude, fractionated and delayed electrograms (EGMs) in left ventricular inferolateral wall. Coronary angiography and phrenic nerve (PN) stimulation were conducted to prevent damage to sensitive structures. Radiofrequency (RF) ablation was performed, achieving near-complete abolition of targeted potentials.