Dofetilide, a new class III antiarrhythmic agent

Area of Science:

• Cardiology
• Pharmacology

Background:

• Atrial fibrillation (AF) and atrial flutter (AFl) are common arrhythmias.
• Current treatments have limitations in efficacy and safety.

Purpose of the Study:

• To evaluate the efficacy and safety of dofetilide for rhythm control in AF and AFl patients.
• To compare dofetilide with existing antiarrhythmic agents.

Main Methods:

• Dofetilide's mechanism of action involves selective blockade of the rapid component of the delayed rectifier outward potassium current.
• Clinical trials assessed conversion rates to normal sinus rhythm (NSR) and maintenance of NSR.
• Dosing is adjusted based on creatinine clearance, with an approximate 10-hour elimination half-life.

Main Results:

• Dofetilide demonstrated superior efficacy compared to flecainide in converting AFl to NSR (70% vs 9%).
• Dofetilide was more effective than sotalol in converting and maintaining NSR in patients with AF and AFl (29% vs 6%).
• Most patients converted to NSR within 24-36 hours.

Conclusions:

• Dofetilide offers a favorable risk:benefit profile for rhythm control in AF and AFl.
• The primary serious side effect is dose-related torsades de pointes, necessitating hospitalization for initial dosing and monitoring.
• Careful patient selection and monitoring are crucial for safe and effective use.