Complex atrial tachyarrhythmias in children with RYR2-mediated catecholaminergic polymorphic ventricular tachycardia: a single-centre paediatric experience

Background Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a malignant inherited arrhythmia syndrome characterised by adrenergically mediated ventricular arrhythmias in structurally normal hearts. Atrial tachycardias (AT) have been increasingly recognised in CPVT, but their prevalence, phenotype, and management in paediatric patients remain poorly defined. Purpose To characterise the arrhythmic spectrum of paediatric RYR2-mediated CPVT, focusing on SVA and their implications for rhythm control strategies, including catheter ablation, left cardiac sympathetic denervation (LCSD) and device therapy. Methods We retrospectively reviewed all consecutive patients <16 years of age diagnosed with CPVT at a single tertiary paediatric centre (2013–2025). Diagnosis followed ESC criteria and required a pathogenic/likely pathogenic (P/LP) RYR2 variant. Clinical data, non-invasive testing (12-lead ECG, Holter ECG, exercise test, echocardiography), implantable loop recorder (ILR) findings, and invasive procedures (electrophysiological study, ablation, LCSD, ICD implantation) were analysed. Results Among 78 individuals evaluated for suspected CPVT, 20 paediatric patients (median age at diagnosis 6.5 years, interquartile range 0.4–12; 60% female) fulfilled diagnostic criteria and carried a P/LP RYR2 variant. During a mean follow-up of 6.8±6.2 years, nine patients (45%) were symptomatic, including three (15%) with resuscitated sudden cardiac arrest. β-blockers were prescribed in 16 patients (80%), and 9 (45%) required additional flecainide. LCSD was performed in 5 (25%), ICDs implanted in 5 (25%), and ILRs in 7 (35%). AT occurred in 3/20 patients (15%) from two families (Figure 1 and 2), all with structurally normal hearts. Documented AT included ectopic atrial tachycardia, atrial flutter and atrial fibrillation, often recurrent and drug-refractory despite maximised β-blocker plus flecainide therapy and LCSD. All three patients underwent complex ablation procedures, including cavo-tricuspid isthmus ablation, focal atrial tachycardia ablation and pulmonary vein isolation guided by 3D electroanatomical mapping. ILR monitoring demonstrated a substantial reduction in ATburden; importantly, no malignant ventricular arrhythmias were preceded by AT, and no deaths occurred. Conclusions In paediatric RYR2-mediated CPVT, AT are observed in a clinically relevant minority and can be particularly challenging to control. A strategy combining intensive pharmacological therapy, LCSD, continuous ILR monitoring and targeted catheter ablation appears feasible and can reduce atrial arrhythmia burden without clear evidence that AT trigger malignant ventricular events. These findings support an individualised rhythm control approach in paediatric CPVT and highlight the need for larger studies to refine risk stratification and device indications in this population.