Flecainide use in arrhythmic patients who have structural heart disease.

Background: Current guidelines recommend the use of only on a limited basis in patients with normal or minimal structural heart disease. The CAST study, the only randomized controlled trials, showed increased mortality from long-term flecainide use in post-myocardial infarction (MI) patients with reduced left ventricular ejection fraction (LVEF). However, many later studies have revealed its safety when used in other structural heart diseases.

Objectives: This study investigates the incidence of ventricular tachycardia (VT) or ventricular fibrillation (VF) VT/VF in patients with structural heart disease compared to those with a normal heart when using flecainide.

Methods: We retrospectively recruited patients who had received at least one dose of flecainide in the past 5 years. Baseline characteristics, indications for flecainide use, and echocardiography results were reviewed. After 1 year, we evaluated the incidence of ventricular arrhythmias and all-cause mortality.

Results: After screening, 447 patients had received at least one dose of flecainide, and 336 patients were included in the study. Forty-seven patients (14%) had structural heart disease as defined by our protocols. Left ventricular hypertrophy (LVH) and impaired LVEF accounted for 28% and 25% of cases, respectively. There were five patients with coronary artery disease (CAD). After 1 year, ventricular arrhythmias occurred in two patients (4.7%) in the structural heart group; these patients had also experienced arrhythmias before receiving flecainide. In the non-structural heart group, ventricular arrhythmias were detected in three patients (1.1%). In multivariate analysis, structural heart disease was not associated with an increased incidence of ventricular arrhythmias (OR = 4.8 (0.6-38.44), p = 0.139).

Conclusion: Our study showed that no patients died due to ventricular arrhythmia, and the incidence of VT/VF was not increased in patients with structural heart disease. A prospective study is needed to further evaluate the safety of flecainide in patients with structural heart disease other than ischemic heart disease.