Propafenone: noninvasive evaluation of efficacy

Area of Science:

• Cardiology
• Pharmacology

Background:

• Refractory ventricular tachyarrhythmias pose significant clinical challenges.
• Antiarrhythmic drug efficacy and safety require thorough evaluation.

Purpose of the Study:

• To assess the efficacy and safety of propafenone in patients with refractory ventricular tachyarrhythmias.
• To evaluate the predictive value of acute drug testing for maintenance therapy response.

Main Methods:

• A noninvasive protocol involving ambulatory monitoring and exercise testing was used.
• Acute drug testing with 450 mg propafenone followed by maintenance therapy (150-300 mg t.i.d.).
• Evaluation of drug effect on ventricular tachycardia (VT), couplets, and ventricular premature beats.

Main Results:

• Overall, 53% of patients responded to propafenone when both monitoring and exercise tests were considered.
• Acute drug testing predicted maintenance therapy response in 84% of patients.
• Propafenone reduced left ventricular ejection fraction in patients with baseline EF < 50% (34% vs 29%, p < 0.01).

Conclusions:

• Propafenone is an effective antiarrhythmic agent for a significant portion of patients with refractory ventricular tachyarrhythmias.
• The drug can be safely continued long-term in some patients, demonstrating sustained efficacy.
• Careful monitoring of left ventricular function is warranted in patients with pre-existing reduced ejection fraction.