High Incidence of Inappropriate ICD Therapies in Young Patients with Catecholaminergic Polymorphic Ventricular Tachycardia

Introduction: We present three young patients with inappropriate shocks of implantable cardioverter defibrillator (ICD) therapies that were performed for the treatment of ventricular arrhythmias due to catecholaminergic polymorphic ventricular tachycardia (CPVT). Case Presentations: Case 1: a 4 year-old boy, CPVT with syncope occurred during swimming. He was treated with an ICD because he complained of syncope repeatedly and administered oral beta-blocker. During follow-up, he had inappropriate shocks due to rapid paroxysmal atrial fibrillation (PAF) during exercise. The PAF was disappeared with an additional flecainide, oral antiarrhythmic agent. Case 2: a 16 year-old boy, CPVT resulting in cardiopulmonary arrest occurred during exercise. He was treated with an ICD and prescribed oral beta-blocker. After that, inappropriate shocks were delivered under his awareness due to the occurrence of rapid PAF. With additional administration of flecainide, inappropriate shocks were decreased. Case 3: a 21 year-old man, an ICD was implanted for CPVT with syncope. He had repeatedly inappropriate shocks due to the occurrence of atrial flutter (AFL). Catheter ablation were performed for eliminating his AFL. Conclusions: In young patients with CPVT, inappropriate ICD therapies easily occur with atrial tachyarrhythmias even if a dual chamber ICD was used. An additional antiarrhythmic drug therapy or catheter ablation should be considered to inhibit such an inappropriate shock.