Efficacy of Implantable Cardioverter Defibrillators in Young Patients With Catecholaminergic Polymorphic Ventricular Tachycardia

Abstract

Background— The effectiveness of implantable cardioverter-defibrillator (ICD) therapy for the management of catecholaminergic polymorphic ventricular tachycardia (VT) in young patients is not known. ICD discharges are not always effective and inappropriate discharges are common, both resulting in morbidity and mortality. Methods and Results— This is a multicenter, retrospective review of young patients with catecholaminergic polymorphic VT and ICDs from 5 centers. ICD discharges were evaluated to determine arrhythmia mechanism, appropriateness, efficacy of therapy, and complications. A total of 24 patients were included. Median (interquartile range) ages at onset of catecholaminergic polymorphic VT symptoms and ICD implant were 10.6 (5.0–13.8) years and 13.7 (10.7–16.3) years, respectively. Fourteen patients received 140 shocks. Ten patients (42%) experienced 75 appropriate shocks and 11 patients (46%) received 65 inappropriate shocks. On actuarial analysis, freedom from appropriate shock at 1 year after ICD implant was 75%. Of appropriate shocks, only 43 (57%) demonstrated successful primary termination. All successful appropriate ICD discharges were for ventricular fibrillation. No episodes of polymorphic VT or bidirectional VT demonstrated successful primary termination. The adjusted mean (95% confidence interval) cycle length of successful discharges was significantly shorter than unsuccessful discharges (168 [152–184] ms versus 245 [229–262] ms; adjusted P =0.002). Electrical storm occurred in 29% (4/14) and induction of more malignant ventricular arrhythmias in 36% (5/14). There were no deaths. Conclusions— ICD efficacy in catecholaminergic polymorphic VT depends on arrhythmia mechanism. Episodes of ventricular fibrillation were uniformly successfully treated, whereas polymorphic and bidirectional VT did not demonstrate successful primary termination. Inappropriate shocks, electrical storm, and ICD complications were common.

Clinical Management of Catecholaminergic Polymorphic Ventricular Tachycardia

“…Careful ICD programming is necessary in CPVT because the effectiveness of appropriate shocks critically depends on the arrhythmia mechanism, usually being effective only when the treated rhythm is ventricular fibrillation. 31,32 Thus, CPVT patients with arrhythmic events despite β-blockers are in dire need of an effective adjunct therapy. The present data conclusively indicate that LCSD represents a viable and effective answer to this predicament.…”

Clinical and genetic profile of catecholaminergic polymorphic ventricular tachycardia in Hong Kong Chinese children

“…1,12,14,16 Some recent studies have suggested that ICD may be harmful to CPVT patients, however, because both appropriate and inappropriate ICD shocks can potentially induce VT storms and cardiac arrest. 16,17 Therefore, ICD implantation should be restricted to patients with symptoms refractory to optimised medical treatment and LCSD. 18 …”

Left Cardiac Sympathetic Denervation

“…7,8 Although ICDs may prevent sudden death in some cases, there are case reports of ICD discharges being proarrhythmic in CPVT and the high voltage function does nothing to prevent arrhythmia from occurring in the first place. 9 For clinicians, LCSD is an appealing approach: its efficacy is independent of patient compliance and it avoids the pulmonary side effects of β-blockers.…”