Management of patients with long QT syndrome.

I have read with great interest the case report entitled “Epicardially placed implantable cardioverter-defibrillator for a child with congenital long QT syndrome” by Sugiyama et al. in the latest issue of the journal [1]. The authors well presented a case of long QT syndrome managed using implantation of an epicardial shock electrode and dose titration of beta-blocker therapy. However, some important issues should be mentioned. As compared to beta-blocker therapy with metoprolol, treatment with nadolol has been shown to significantly decrease breakthrough cardiac events in symptomatic patients [2]. Furthermore, the therapeutic efficacy of nadolol was better in patients with long QT syndrome, particularly in LQT2 [3], [4]. An implantable cardioverter–defibrillator should be considered early in the diagnosis of patients with recurrent symptoms despite receiving beta-blocker therapy, although inherent difficulties are related to much smaller body weight, body surface area, and continued growth of children. Another limitation of high-dose beta blocker therapy is that negative chronotropic effects resulted in potential device pacing attempts, which can cause atrial arrhythmias and left ventricular dysfunction with long-term atrial and ventricular pacing, respectively. Single-coil defibrillator lead implanted at the free wall, using an active can, might be an alternative approach (Fig. 1). Last, device programming using high counts with initial detection, upper threshold levels >250 bpm with a single detection zone and maximum shock output, and features minimizing ventricular pacing should be considered in all patients with inherited arrhythmia syndromes.

Fig. 1

Direct radiography shows abdominally located active can and epicardially implanted single-coil defibrillator lead (arrow) with pacing and sensing electrodes (arrow heads) on postero-anterior (a) and left-lateral (b) projections. Epicardially implanted single-coil electrode seen on the beating heart (c).

Conflict of interest

All authors declare no conflict of interest related to this study.