The purpose of this study was to determine
propafenone's effectiveness in terminating and suppressing supraventricular arrhythmias using meta-analytic techniques. Published abstracts and manuscripts with these goals were selected and data abstracted on conversion and maintenance of sinus rhythm. Data were pooled using standard meta-analytic techniques and analyzed according to observation times, trial design (randomized versus nonrandomized), and route of
drug administration.
Propafenone successfully terminated 83.8% (95% confidence interval 78.1-89.7%) of
supraventricular tachycardias. For
supraventricular tachycardias, the proportion of patients remaining in sinus rhythm without recurrent
arrhythmia was 64.6% (58.1-71.1%) at 1 year. The likelihood of converting a paroxysm of
atrial fibrillation (AF) increased over time, with 76.1% (72.8-79.4%) of patients in sinus rhythm 24 hours after initiation of
therapy. Patients receiving intravenous
therapy were more likely to convert to sinus rhythm in the first 4 hours after
drug administration. The treatment benefit of
propafenone versus placebo in converting sinus rhythm was greatest in the first 8 hours
after treatment (treatment benefit of 31.5% [24.5-38.5%] at 4 hours and 32.9% [24.3-41.5%] at 8 hours, p <0.01). This treatment benefit decreased to 1 1.0% (-0.6-22.4%) after 24 hours.
Propafenone was effective in suppressing recurrences of AF in 55.4% (51.3-59.7%) at 6 months and 56.8% (52.3-61.3%) at 12 months. Thus,
propafenone is effective in terminating
supraventricular tachycardias and AF in the vast majority of patients. Suppression of
arrhythmia recurrences is feasible in most patients, although its effectiveness decreases over time.