Myotonic dystrophy associated with QT prolongation and torsade de pointes

A rare case of myotonic dystrophy (MD) with congestive heart failure, assoc iated with QT prolongation and torsade de pointes (TdP) is reported. A 53-y ear-old woman was admitted to the hospital because of congestive heart fail ure. Electrocardiograph (ECG) showed first-degree atrioventricular block an d QT prolongation. During hospitalization, TdP appeared but returned to sin us rhythm spontaneously. As the patient had quadriplegia, a myopathic face, cataracts, diabetes mellitus, and an increased number of cytosine-thymine- guanine (CTG) repeats (760 repeats), she was diagnosed as having MD. Electr ocardiographic analysis of her family also revealed abnormal QT(U) prolonga tion in her daughter and brother who both had MD, while ECG findings of oth er family members without MD were normal. Thus, the presence of QT(U) prolo ngation was associated with MD in this family.