[Antiarrhythmic treatment with mexiletine in acute myocardial infarction (author's transl)]

The effect of an introduced i.v. bolus of 250 mg of mexiletine was checked in cases of acute myocardial infarction with ventricular premature beats. On the 19 observed subjects 17 are male and 2 female: 18 cases with acute myocardial infarction and 1 with acute coronary failure. The introduction of the bolus was followed by an infusion of 0.75 mg/m for the successive four days. After 60 m' no significant changes in arterial pressure and in the heart rate were recorded. The Extrasistolies decrease from 11 +/- 3 to 3 +/- 2/m' (-71%, p less than 0.01); PQ and QT variations were not significant. After four days of infusion, systolic arterial pressure decrease from 135 +/- 4 to 121 +/- 3 (-10%; p less than 0.01), sinusal rate drops from 90 +/- 4 to 80 +/- 3 (-12%, p less than 0.05). The changes of diastolic arterial pressure, PQ and QT were not significant. Extrasistolies disappears entirely. A comparison between a mexiletine and a xilocaine i.v. bolus showed that mexiletine performs a higher antiarrhythmic activity.