Acquired left ventricular hypertrabeculation/noncompaction (LVHT) is rare and has been described in patients with mitochondriopathy, Barth syndrome, and Becker muscular dystrophy. Here we report acquired LVHT in a 28-year-old man with Duchenne muscular dystrophy who required non-invasive, positive-pressure ventilation for muscular respiratory failure since age 16 years. Transthoracic echocardiography at age 22 years revealed enlarged left atrium and ventricle and reduced fractional shortening, but no LVHT. Transthoracic echocardiography at age 27 years revealed enlarged left atrium and ventricle, systolic dysfunction, mitral insufficiency, and, surprisingly, LVHT. The cause and pathomechanism of acquired LVHT in this patient remained speculative.