Antiarrhythmic efficacy of mexiletine, propafenone and flecainide in ventricular premature beats. a comparative study in patients after myocardial infarction
Klempt, H.W.; Nayebagha, A.; Fabry, E.
Zeitschrift für Kardiologie 71(5): 340-349
In 12 patients with coronary artery disease, 11 of them with previous myocardial infarction, the antiarrhythmic effects of orally administered flecainide (F.), mexiletine (M.) and propafenone (P.) were examined. The doses amounted to 400 mg F., 600 mg M., and 900 mg P. daily. The administration was made randomized with a change between placebo and verum periods with a duration of 3 respectively 4 days. The 3 antiarrhythmic agents reduced significantly the number of ventricular premature beats (VPB), the reduction of VPB amounted to 94.2% (F.), 80.2% (P.), and 52.8% M.). Repetitive VPB were reduced about 98.8 % (F.), 96.8% (P.) and 83.33% (M.). The Lown-Index diminished by about 1.45 classes (F.) 1.18 classes (P.) respectively 0.55 classes (M.). A complete suppression of VPB was obtained only in one patient under medication with F. F. and P. lengthened the duration of P, PQ and QRS, whereas M. did not affect these parameters. Heart rate and QT remained unchanged. Subjective side-effects of the 3 agents were similar. Without of the influence on the ECG, objective side effects were missed. The long plasma half-life of F. (19.0 +/- 5.2 h) guarantees an antiarrhythmic effect over a period of 24 hours if the substance is administered twice daily. The large variance of plasma half-life can cause some difficulties in the finding of individually required dose of F.