Acute conversion of persistent atrial fibrillation during dofetilide initiation

Area of Science:

• Cardiology
• Pharmacology

Background:

• Dofetilide (D) is a selective potassium channel blocker approved for atrial fibrillation (AF) treatment.
• Previous trials focused on patients with left ventricle dysfunction or heart failure, reporting lower acute conversion rates (6-30%).
• A hypothesis was formed that D might achieve higher conversion rates in healthier patients with persistent AF.

Purpose of the Study:

• To evaluate the acute pharmacological conversion rate of dofetilide in a cohort of patients with persistent AF and preserved ejection fraction.
• To assess the safety and tolerability of dofetilide in this patient population.
• To identify factors predicting successful cardioversion with dofetilide.

Main Methods:

• Eighty consecutive patients with persistent AF received dofetilide, with dosing adjusted for creatinine clearance and QTc intervals.
• Patients were monitored via telemetry for at least six dosing intervals.
• Demographic and clinical data, including ejection fraction, coronary artery disease, and left atrial dimension, were collected.

Main Results:

• 77% of patients converted to sinus rhythm (SR) with dofetilide alone after 2.2 doses.
• Acute pharmacological conversion rates increased with dose: 20% (125 mcg bid), 44% (250 mcg bid), and 85% (500 mcg bid).
• Failure to convert was associated with larger left atrial diameter and longer AF duration. No cases of torsade de pointes or intolerance were reported.

Conclusions:

• Dofetilide demonstrated a high pharmacological conversion rate (77%) in healthier patients with persistent AF.
• The drug showed an incremental dose response and was safe and well-tolerated.
• Left atrial size and AF duration were predictors of successful cardioversion, suggesting dofetilide is a valuable option for AF conversion.