Is flecainide safe or appropriate for a patient with heart failure with preserved ejection fraction (HFpEF)?

Flecainide in HFpEF

Flecainide is safe and appropriate for use in patients with HFpEF, provided they have preserved left ventricular systolic function and no coronary artery disease. The 2024 ESC guidelines explicitly include HFpEF among the conditions where flecainide can be used for rhythm control in atrial fibrillation, while the primary contraindications are HFrEF (reduced ejection fraction), severe left ventricular hypertrophy, and coronary artery disease 1.

Guideline-Based Recommendations

The most recent 2024 ESC AF guidelines provide clear direction:

• Flecainide or propafenone is recommended for long-term rhythm control in AF patients, excluding those with impaired left ventricular systolic function, severe left ventricular hypertrophy, or coronary artery disease 1
• Notably, HFpEF is NOT listed as a contraindication in these guidelines
• In contrast, dronedarone is explicitly recommended for patients with HFpEF, HFmrEF, ischemic heart disease, or valvular disease 1

Critical Distinction: HFpEF vs HFrEF

The key safety concern with flecainide relates to reduced ejection fraction, not preserved ejection fraction:

• The FDA label warns about negative inotropic effects and worsening heart failure, particularly in patients with NYHA class III-IV heart failure or ejection fraction <30% 2
• The 2022 AHA/ACC/HFSA guidelines reference the CAST trial, which studied post-MI patients with reduced EF and ventricular arrhythmias—a completely different population than HFpEF 3
• Historical data from the 1980s showed flecainide-induced heart failure occurred primarily in patients with EF ≤30% 4, 5

Practical Application for HFpEF Patients

Use flecainide in HFpEF patients when:

• Ejection fraction is preserved (≥50% by current definitions)
• No significant coronary artery disease
• No severe left ventricular hypertrophy
• NYHA class I-II symptoms (avoid in class III-IV)

Starting approach:

• Begin with 50 mg twice daily for supraventricular arrhythmias 2
• Monitor ECG for conduction changes (PR, QRS prolongation) 2
• Increase by 50 mg increments every 4 days if needed, up to maximum 300 mg/day 2
• Maintain trough plasma levels <0.7-1.0 mcg/mL when feasible 2

Emerging Evidence Supporting Safety

Recent systematic reviews challenge the broad extrapolation of CAST trial results:

• A 2026 meta-analysis of 35,886 patients found no increased ventricular arrhythmia risk with class Ic agents in structural heart disease populations (HR 0.73,95% CI 0.51-1.03) 6
• A 2025 retrospective study showed no increased VT/VF incidence in structural heart disease patients, including those with LVH (OR 4.8,95% CI 0.6-38.44, p=0.139) 7
• Contemporary reviews argue for phenotype-specific reassessment rather than blanket contraindications 8

Common Pitfalls to Avoid

1. Don't confuse HFpEF with HFrEF: The preserved ejection fraction fundamentally changes the risk profile
2. Screen for coronary disease: Even in HFpEF, active ischemia or significant CAD remains a contraindication
3. Assess baseline conduction: Avoid in patients with pre-existing significant conduction disease unless paced 2
4. Monitor for heart failure decompensation: While less common in HFpEF, close monitoring of volume status and symptoms remains essential 2

The bottom line: HFpEF with preserved systolic function and no CAD is not a contraindication to flecainide based on current guidelines and emerging evidence, making it a reasonable option for rhythm control in appropriately selected patients.