HEMODYNAMIC AND ANTIARRHYTHMIC EFFECTS OF ORAL-THERAPY WITH PRAJMALINE AND MEXILETINE IN PATIENTS WITH EXTRASYSTOLES - A COMPARISON OF GROUPS

The hemodynamic and antiarrhythmic effects of an oral 7-day therapy wi th 3 x 300 mg/day mexiletine (n = 16) and 4 x 20 mg prajmaline (n = 13 ) were investigated in 29 patients requiring therapy for ventricular e xtrasystoles by using right heart catheterization, (99m)technetium ven triculography, and 24-h Holter monitoring. Neither drug, while inducin g significant suppression of ventricular ectopies, in particular of co uplets and triplets, and therapeutic plasma levels, provoked impairmen t of ventricular pump function (mexiletine group: EF 52.8 vs. 53.5%, C I 3.4 vs. 3.6 l/min/M2, PAPm 17.4 vs. 17.5 mmHg, SVR 1304 vs. 1265 dyn . s . cm-5; prajmaline group: EF 48 vs. 44.9%, CI 3.7 vs. 3.7 l/min/m 2, PAPm 18.5 vs. 17.7 mmHg, SVR 1977 vs. 2489 dyn . s . cm 5). Under e xercise, there were also no cardiodepressive effects found with either drug. Therapeutic plasma levels of mexiletine and prajmaline at 1 133 +/- 446 ng/ml and 113.2 +/- 88 ng/ml, respectively, were found at the time of right heart catheterization. The occurrence of couplets was s ignificantly reduced by 93 % under mexiletine and by 91 % under prajma line. Gastrointestinal and central nervous side effects were more freq uently reported with mexiletine compared to prajmaline, with prajmalin e being tolerated very well except for one patient. None of the drugs showed significant effects on either heart rate, arterial pressure or pulmonary artery mixed oxygen saturation (p > 0.05).