Nonsustained VT in a Patient with Genetically Proven Andersen-Tawil Syndrome (LQT 7)

Abstract

Andersen-Tawil syndrome, LQT 7, is a genetic disorder associated with mild QT prolongation and ventricular tachyarrhythmia (especially bidirectional VT) which is well known to be notoriously difficult to suppress by antiarrhythmic drugs. We here report a 41 year-old female patient with LQT 7, who carried a missense mutation of R 67 W in KCNJ2. She admitted to our hospital because of syncope. She had none of periodic paralysis, dysmorphic features and family history. Frequent PVCs and nonsustained VT (NSVT) have been pointed out since 13 years old although she was asymptomatic until her admission to our hospital. Twelve-lead ECG exhibited marked QT (QU) prolongation of 720 ms associated with frequent PVCs, which were easily escalated into NSVT by exercise and usually presented as a bidirectional form. A 24-hour Holter recording revealed more than 35,000 beats of PVCs/NSVTs. Combination of oral flecainide (200 mg, bid) and bisoprolol (1.25 mg, qd) remarkably reduced daily number of PVCs/NSVTs to less than 1,000 beats, and rendered exercise-induced bidirectional NSVT before the medication to infrequent PVCs after the medication. No syncope recurred during 6 month follow-up. In conclusion, combination of flecainide and bisoprolol suppressed bidirectional VT in an LQT 7 patient.