Nationwide experience of catecholaminergic polymorphic ventricular tachycardia caused by RyR2 mutations.

Objective: The aim of this study was to characterise disease penetrance, course of disease and use of antiarrhythmic medication and implantable cardioverter-defibrillator (ICD) therapy in a Danish nationwide cohort of patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) due to mutations in the ryanodine receptor-2 () gene.

Methods: The study population was identified through the national hereditary heart disease database (Progeny). The study population was divided into three groups: probands, symptomatic and asymptomatic relatives.

Results: We identified 23 symptomatic probands, 18 symptomatic and 10 asymptomatic relatives with a mutation. Twenty (87%) probands and 10 (36%) relatives had severe presenting symptoms (sudden cardiac death (SCD), aborted SCD (ASCD) or syncope).As compared with symptomatic relatives, probands had lower age at onset of symptoms (16 years (IQR, 10-33) vs 43 years (IQR, 25-54), p<0.0001) and were more prone to fatal or near-fatal events (ASCD, SCD) (16vs5, p<0.0001). Twenty-eight patients had an ICD implanted, and eight experienced appropriate ICD therapy during follow-up (65 months (IQR, 43-175)). Electrical storm was seen in two of the 28 ICD treated patients (7%). No patients receiving treatment died during follow-up (57 months (IQR, 32-139)). Multifocal atrial tachycardia was the predominant symptom in five patients.

Conclusions: In a national cohort of RyR2 mutation-positive CPVT patients, SCD, ASCD and syncope were presenting events in the majority of probands and also occurred in 36% of relatives identified through family screening. Probands were younger at disease onset and more prone to fatal or near-fatal events than relatives.