Paper-like Bilateral Sternocleidomastoid Muscle Atrophy May Suggest the Occurrence of Sustained Ventricular Tachycardia

Key Teaching Points•Myotonic dystrophy must always be considered as the potential cause of ventricular tachycardia (VT), as it is associated with the risk of sudden death caused by asystole following atrioventricular block or VT in patients with myotonic dystrophy.•Bilateral sternocleidomastoid muscle atrophy is one of the characteristic findings of myotonic dystrophy, and the range of prevalence of myotonic dystrophy ranges from approximately 1:100,000 in some areas of Japan to approximately 1:10,000 in Iceland, with a European prevalence of 3–15 per 100,000.•Close attention to a paper-like bilateral sternocleidomastoid muscle atrophy on computed tomography images could help diagnose VT with muscular dystrophy. •Myotonic dystrophy must always be considered as the potential cause of ventricular tachycardia (VT), as it is associated with the risk of sudden death caused by asystole following atrioventricular block or VT in patients with myotonic dystrophy.•Bilateral sternocleidomastoid muscle atrophy is one of the characteristic findings of myotonic dystrophy, and the range of prevalence of myotonic dystrophy ranges from approximately 1:100,000 in some areas of Japan to approximately 1:10,000 in Iceland, with a European prevalence of 3–15 per 100,000.•Close attention to a paper-like bilateral sternocleidomastoid muscle atrophy on computed tomography images could help diagnose VT with muscular dystrophy.