[Comparative study of the anti-arrhythmic activity of mexiletine and lidocaine in ventricular hyperkinetic arrhythmias].

The present study has been carried out on 50 patients admitted to C.C.U. for cardiovascular diseases of various ethiology (44 patients with ischemic heart disease) who required antiarrhythmic theory for different types of ventricular arrhythmias: monofocal ventricular extrasistoles greater than 6/min, bigeminal ventricular extrasistoles, polifocal and/or repetitive ventricular tachycardias. The patients have been randomly allocated into two groups of 25 subjects: the first one has been treated with Mexiletine and the second with Lidocaine. In Mexiletine treated group the following results have been obtained: 19 excellent (76%), 4 good (16%) and 2 ineffective (8%). In Lidocaine treated group: 11 excellent (44%), 5 good (20%) and 9 ineffective (36%). Statistical analysis by chi square test has shown significant prevalence of favourable results in Mexiletine treated patients (p less than 0.02; X(2) = 5.33). Moreover, in relation to the type of arrhythmias, Mexiletine succeded in a greater number of cases of complicated ventricular extrasistoles (bigeminal, polifocal and/or ripetitive) and in ventricular tachicardias. Mexiletine also has induced significant reduction of QTc and significant increase of cardiac rate, whereas it did not affect significantly the PR interval and blood pressure. None of these parameters has been influenced significantly by Lidocaine. Side effects have been similar for both drugs and generally mild. On the basis of results and in accord with the electrophysiological properties, the Authors discuss the possible mechanism of action and the role of Mexiletine in the treatment of ventricular arrhythmias particularly those complicating acute phase of myocardial infarction.