title: A cautionary tale: the risks of flecainide treatment for myotonic dystrophy.
abstract: Myotonic dystrophy (MD) is associated with important cardiac abnormalities, and 30% of deaths are attributable to cardiac causes, predominantly arrhythmias. Sodium channel blockers have been used to improve muscle strength and relaxation in MD. Flecainide is a potent selective blocker of the mutant sodium channel in myotonia and inhibits the abnormal noninactivating sodium current in both painful myotonia congenita and painless MD with a resultant improvement in muscle relaxation. We describe the case of a 41-year-old woman with MD who developed ventricular tachycardia (VT) while taking flecainide to improve her muscle strength. Flecainide was discontinued and VT could not subsequently be induced. Although flecainide is an effective antiarrhythmic agent, it may also be proarrhythmic, particularly in patients at risk for VT. We recommend careful cardiac assessment, risk stratification, and consideration of high-risk patients for early screening electrophysiological studies, especially if considering use of a class 1 antiarrhythmic agent.
authors.affiliation: From the Waller Cardiac Department, St. Mary's Hospital, Imperial College, London, UK.
authors.forename: Diana A
authors.initials: DA
authors.lastname: Gorog
authors.forename: Georgina
authors.initials: G
authors.lastname: Russell
authors.forename: Alina
authors.initials: A
authors.lastname: Casian
authors.forename: Nicholas S
authors.initials: NS
authors.lastname: Peters