[Flecainide: a new antiarrhythmic agent].

The authors report their clinical experience with flecainide, a new Class I antiarrhythmic drug, in 44 patients classified into three groups. The first group (7 cases) comprised patients with a wide range of arrhythmias sensitive to the usual antiarrhythmic agents. The second (17 cases) were atrial arrhythmias resistant to the usual antiarrhythmic agents and were mainly vagal atrial arrhythmias. The last group (20 cases) comprised patients with resistant VT, 14 of whom had underlying cardiac disease (8 chronic infarcts). The results obtained were analysed by a score test because of the wide range of arrhythmias and the wide variations in their spontaneous recurrent rate. The antiarrhythmic effect was checked by repeated Holter monitoring correlated with the results of interrogation. Provocative pacing studies were performed in 5 cases of inducible VT under therapy. The results with flecainide were compared with those obtained with reference Class I antiarrhythmics: quinidine, 700 to 1100 mg/day or disopyramide, 600 mg/day. Amiodarone was often associated with each Class I antiarrhythmic because of the resistant nature of these arrhythmias. In group I the results with flecainide were equivalent to those of quinidine. In the other two groups the results were significantly better than those of the reference antiarrhythmic: mean scores: group II 3,20 +/- 0,5 compared to 1,9 +/- 0,4 (p less than 0,01); group III 3,70 +/- 0,37 compared to 1,85 +/- 0,22 (p less than 0,001). Tolerance was good apart from neurosensory side effects (loss of accomodation, vertigo) which were dose dependent and which led to the withdrawal of therapy in only 4 cases. Four types of cardiac side effects were observed: aggravation of existing sinoatrial block (1 case); aggravation of existing intraventricular block (2 cases); aggravation of contractile function which was very poor before therapy (2 cases); and sudden death during therapy in patients with ischemic heart disease in cardiac failure and with incessant resistant VT (2 cases). In these instances the role of the drug cannot be confirmed. These complications were observed with doses of more than 5 mg/kg/day and in patients with cardiac failure. Two of these patients had serum flecainide levels which were very high. It may therefore be possible to reduce the incidence of these complications by adapting dosage to the patient's clinical state and to the serum drug levels.(ABSTRACT TRUNCATED AT 400 WORDS)