[The efficacy of oral treatment with flecainide for paroxysmal atrial fibrillation: correlation with plasma concentration].

In the acute treatment of paroxysmal atrial fibrillation several drugs can be used. The aim of our work was to assess the efficacy of a single oral dose of flecainide in the conversion to sinus rhythm by correlating this data with flecainide plasma concentration. We have considered 37 patients affected by paroxysmal atrial fibrillation (for more than 8 hours) randomly assigned to the following two groups: group A, 19 patients, mean age 44.4 +/- 1.9 years) treated with flecainide (200 mg) and control group B (18 patients, mean age 46.6 +/- 1.8 years). This was done in order to point out any possible overlap between pharmacological and spontaneous conversion to sinus rhythm. In all patients, the following were performed: a Holter recording (524 hours) to evaluate the time of conversion to sinus rhythm (t-conversion to sinus rhythm), a determination of flecainide plasma concentration (after 150 flecainide administration) an Rx, an Echo-2D/Doppler test and an estimation of thyroid function. The Rx, the Echo-2D/Doppler and the endocrinological data in the 2 groups did not show any significant differences. We obtained a conversion to sinus rhythm in all but one of the group A patients (time of conversion to sinus rhythm 162 +/- 83 min) and in just 5 group B patients (time of conversion to sinus rhythm 1118 +/- 125 min) (time of conversion to sinus rhythm A vs B p less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)