Long-term follow-up of patients with long-QT syndrome treated with β- blockers and continuous pacing

Background - The long-QT syndrome is associated with sudden cardiac death. Combination of β-blocker and pacing therapy has been proposed for treatment of drug-resistant patients. The purpose of this study was to summarize our long-term experience with combined therapy in patients with long-QT syndrome. Methods and Results - A total of 37 patients with idiopathic long-QT syndrome were treated with combined therapy consisting of continuous cardiac pacing and maximally tolerated β-blocker therapy and followed up for 6.3±4.6 years (mean±SD). The group consisted of 32 female and 5 male patients with a mean age of 31.6 years. The mean paced rate was 82±7 bpm (range, 60 to 100 bpm). On follow-up, recurrent symptoms caused by pacemaker malfunction were documented in 3 patients. Four patients died during the follow-up period: 2 adolescents stopped β-blocker therapy, 1 patient died suddenly while treated with combined therapy, and 1 patient died of unrelated causes. In addition, 3 patients had resuscitated cardiac arrest while on combined therapy, and 1 patient had repeated, appropriate implantable cardioverter-defibrillator discharges on follow-up. Conclusions - Because 28 of 37 patients remain without symptoms with β-blocker therapy and continuous pacing, combined therapy appears to provide reasonable, long-term control for this high-risk group. However, the incidence of sudden death and aborted sudden death (24% in all patients and 17% in compliant patients) strongly suggests the use of a 'back-up' defibrillator, particularly in noncompliant adolescent patients. Implantable cardioverter-defibrillator therapy, however, may be associated with recurrent shocks in susceptible patients.