Flecainide in Idiopathic Premature Ventricular Contractions and Related Cardiomyopathy

The UNIFLECA study is a prospective, single-arm, non-randomized observational cohort designed to evaluate the long-term efficacy and safety of flecainide (in the form of Sanocard) in adult patients with frequent idiopathic premature ventricular contractions (PVCs) and suspected PVC-induced cardiomyopathy (PVCi-CMP). Despite being considered benign in structurally normal hearts, a persistently high PVC burden-particularly above 10%-is increasingly recognized as a cause of reversible left ventricular dysfunction and a potential trigger for cardiomyopathy. This condition is frequently underdiagnosed and may lead to unnecessary treatments or delayed intervention.

The study targets a unique population: symptomatic patients with idiopathic PVCs who have structurally normal hearts and have either declined catheter ablation or are ineligible for invasive procedures. Each patient undergoes comprehensive baseline cardiac evaluation, including transthoracic echocardiography, cardiac magnetic resonance imaging (CMR) to exclude late gadolinium enhancement or myocardial scar, and coronary angiography or non-invasive equivalent to rule out ischemic heart disease. Two 24-hour Holter ECG recordings, taken at least 30 days apart, are used to confirm persistent high PVC burden (>5%).

Flecainide, a Class IC antiarrhythmic agent with sodium channel-blocking properties, is administered as monotherapy. The initial dose is 100 mg/day and may be titrated up to 200 mg/day based on clinical response, patient tolerability, and QRS interval monitoring. Beta-blockers are discontinued unless used for unrelated comorbidities such as hypertension. Patients are monitored with serial 12-lead ECGs, Holter recordings, and echocardiograms at baseline and every three months over a total follow-up period of three years.

The primary endpoint is the percentage reduction in PVC burden as measured by 24-hour Holter ECG. Secondary endpoints include (1) improvement in left ventricular ejection fraction (LVEF), (2) symptom relief as assessed by structured patient questionnaires focusing on palpitations, bradysphygmia, fatigue, dizziness, and exercise intolerance, (3) incidence of adverse events including proarrhythmia, conduction disturbances, and neurological side effects, and (4) adherence to long-term flecainide therapy, including need for dose modifications or drug discontinuation.

This investigator-initiated study is being conducted across tertiary arrhythmia centers in Greece. It aims to fill a significant evidence gap in the long-term pharmacologic management of idiopathic PVCs and PVCi-CMP. Preliminary results indicate significant PVC burden reduction and symptomatic improvement, supporting the potential utility of flecainide as an effective non-invasive therapeutic option in appropriately selected patients. Data from this study will contribute to optimizing treatment strategies for idiopathic ventricular arrhythmias in the absence of structural heart disease, supporting the use of personalized medicine and risk stratification.