Cunningham T, et al. – In this present study, the safety and effectiveness of flecainide were examined in children with normal hearts and those with congenital heart disease (CHD) or cardiomyopathy (CMO). Results of this study proved that flecainide was a safe and effective antiarrhythmic medication, even for children with underlying CHD.

Methods

• In this study, 175 patients (20 with CHD and two with CMO) receiving flecainide were reviewed.
• When comparing patients with CHD to those with normal hearts, patients with CHD were younger at diagnosis (median age 19 days; IQR 3–157.5 days vs normal heart patients median age 21 days; IQR 7–172 days, p = 0.4) and severe cardiac dysfunction was more prevalent (30% in CHD patients vs 8% in normal heart patients, p = 0.009). 

Results

• Between the two groups, treatment duration did not differ (CHD patients median duration 52 weeks; IQR 27–91.5 weeks vs normal heart patients median duration 55 weeks; IQR 32–156 weeks, p = 0.5). 
• Cardiac dysfunction resulting in flecainide discontinuation occurred in two patients (1%), one with CHD and one without.
• 3 patients reported proarrhythmia (2%) and there were no cardiac arrests during follow–up.
• There was one death in this cohort in a patient with severe CHD and an RSV infection (<1%).
• Between the groups, arrhythmia control did not differ (90% in CHD patients vs 77% in normal heart patients, p = 0.2). 
• In this cohort, flecainide was well tolerated.
• Fewer than 3% discontinued medication due to flecainide–associated adverse events.
• In this study, no difference was observed in the incidence of adverse events between patients with normal hearts and patients with CHD.