What does flecainide do for atrial fibrillation?
Flecainide is a class IC anti‑arrhythmic that blocks sodium channels, slowing conduction through atrial tissue. When used for rhythm control, it can restore normal sinus rhythm in a subset of patients with atrial fibrillation (AF) and help maintain it with repeat dosing.
How does its effectiveness compare to other rhythm‑control drugs?
In short‑term trials, flecainide restores sinus rhythm in roughly 70‑80 % of patients who receive an initial dose. Over the long term, its success rate drops, and many patients require additional medication or cardioversion. Compared with drugs such as amiodarone or sotalol, flecainide is faster at converting AF but carries a higher risk of pro‑arrhythmia, especially in people with underlying heart disease.
When should patients consider flecainide?
Flecainide is usually prescribed for patients with no structural heart disease, preserved ejection fraction, and a history of paroxysmal AF that has not responded to rate‑control therapy. It is not recommended for people with coronary artery disease, heart failure, or significant conduction abnormalities.
Are there safety concerns with flecainide in atrial fibrillation?
Yes. Flecainide can induce ventricular arrhythmias, particularly in the presence of ischemia or left‑ventricular dysfunction. The drug can also prolong the QT interval in some patients. Because of these risks, a baseline ECG and a careful cardiac evaluation are mandatory before starting therapy.
How long does flecainide need to work after a dose?
A single loading dose of 200 mg (or 300 mg for larger patients) is often given under monitoring. Sinus rhythm is usually observed within 30 minutes to an hour. If rhythm is not restored, the dose can be repeated, but the risk of pro‑arrhythmia rises with each additional dose.
Can flecainide be used with other medications?
Flecainide is metabolized by CYP2D6 and can interact with drugs that affect this enzyme. Concomitant use with potassium‑sparing agents, digoxin, or drugs that prolong the QT interval may increase adverse effects. Patients should review all medications with their clinician.
What happens if flecainide fails to stop AF?
If the drug does not restore sinus rhythm or if the rhythm breaks down again, clinicians may switch to another anti‑arrhythmic, add a β‑blocker, or consider electrical cardioversion. In patients whose rhythm control fails repeatedly, long‑term rate control or ablation may be the next steps.
Who is the best candidate for flecainide therapy?
The ideal candidate is a younger or middle‑aged individual with paroxysmal AF, no significant structural heart disease, normal left‑ventricular function, and a willingness to adhere to regular ECG monitoring. Patients with prior heart attacks, heart failure, or severe valvular disease should avoid flecainide.