Restrictive cardiomyopathy is a rare paediatric myocardial disorder causing diastolic dysfunction with preserved systolic function. We report a 14-year-old girl with idiopathic restrictive cardiomyopathy and recurrent systemic thromboemboli (stroke, limb ischaemia, renal infarction, and intracardiac thrombi) despite sinus rhythm. Anticoagulation resolved thrombi. She is currently awaiting heart transplantation. Early recognition, prompt anticoagulation, genetic evaluation, and consideration for transplantation are essential to optimise outcomes.

We report the first Caucasian patient with CALM2 p. Asn98Ser, a 2-year-old girl who survived out-of-hospital cardiac arrest after emotional stress. The initial rhythm was broad-complex tachycardia degenerating into ventricular fibrillation. Normal QT intervals and absent structural disease suggest a CPVT-like presentation, highlighting diagnostic and management challenges in calmodulinopathy.

Therapeutic drug monitoring of flecainide in children using plasma concentration measurements is undertaken by some clinicians. There is very little published evidence surrounding factors which influence plasma flecainide concentration, particularly in paediatric populations. We undertook a retrospective study of 45 children receiving flecainide to identify factors that influence its plasma concentration. Patients receiving a dose of 6 mg/kg/day had a higher mean plasma flecainide concentration than those receiving lower doses. Younger age and lighter weight were also associated with higher plasma flecainide concentrations. Children aged younger than 1 year receiving flecainide three times a day had a higher mean plasma flecainide concentration than older children who received flecainide twice a day. All supratherapeutic levels occurred in children aged less than 1 year who were receiving flecainide three times a day. Supratherapeutic levels were more common in those receiving 6 mg/kg/day while subtherapeutic levels were more common in those receiving 2 mg/kg/day. A supratherapeutic level did not correlate with adverse effects or clinical toxicity. Our results would suggest the need for a change of practice from prescribing flecainide at a frequency of three times a day in children aged younger than 1 year to twice a day in line with other ages.