Effects of Oral Propafenone in Patients with Frequent Ventricular Extrasystoles

Propafenone is an antiarrhythmic drug with class IC sodium channel blocking agent with mildly -blocking and calcium channel blocking properties. Oral therapy effectively suppresses supraventricular and ventricular arrhythmias. However, experience with propafenone in Chinese patients is limited. To assess the efficacy and safety of oral propafenone in Chinese patients with frequent ventricular extrcrsys-toles ( >20/hour in average ) and normal treadmill exercise test and echocardiographic results, 23 patients ( 14 males and 9females, mean age 56.5 years ) were studied using 24-hour Holter ECG recording. Oral propafenone at a dose of 300 mg/day (12 patients ) and 450 mg /day (II patients) was then given. The 24-hour Holter ECG recording was repeated 4 weeks later to evaluate the suppressive effect of propafenone. Blood pressure and adverse effects were also recorded at each visit. When all patients taking 300 mg/day were analyzed as a group, no stastistically significant suppresion of ventricular extrasystoles was noted, whereas patients taking 450 mg/day had significant suppression of total ventricular ectopies, isolated ventricular ectopies, and average ventricular ectopies. Therapeutic success ( >85% suppression of ventricular ectop ) was achieved in 41. 7% (5/12) of in those taking 300 mg/day and in 63. 6% (7/11) of those taking 450 mg/day. Of the three patients taking 450 mg/day, who did not achieve > 85% suppression, two patients showed significant suppression of ventricular ectopies without adverse effects when the dose was increased to 600 mg/day. During the treatment period, no patient reported arrhythmia - related ill effects or developed hemodynamic instability, although three patients had transient and asymptomatic bradycardia during the 24-hour Holter ECG recording. There- fore, we conclude that oral propafenone is effective at a dose range of 300 to 600 mg/day is effective and safe in the suppression of frequent ventricular extrasystoles in patients with functionally normal heart.