Combination ethacizin and ethmozin treatment of resistant ventricular ectopy: theoretical, experimental, and clinical study.

Published

Journal Article

Ethmozin (Moricizine HCl) and ethacizin are two class I antiarrhythmic drugs with different rate constants of interaction with the sodium channel. Computer simulation using the "guarded-receptor" model predicted that the combination of ethacizin and ethmozin should exert a greater decrease in excitability and conduction at short coupling intervals, but little effect at normal heart rates (HR). To test this prediction, we measured intraventricular conduction delay in canine hearts in vivo. In agreement with the model, the combination more potently prolonged the delay only at intervals < 600 ms as compared with ethacizin alone. Combination therapy was tested in 6 patients with idiopathic ventricular ectopic depolarizations (VEDs). Three patients were resistant to either ethmozin or ethacizin monotherapy, and three could not tolerate effective doses because of side effects. Quantitative continuous ECG monitoring showed that total VEDs in the resistant group decreased 0 and 17 +/- 13% for 400 and 800 mg/day ethmozin and 18 +/- 12 and 55 +/- 12% for 100 and 200 mg/day ethacizin, respectively. Combined therapy with ethmozin (400 mg/day) and ethacizin (100 mg/day) reduced the number of VEDs by 78 +/- 2% in these patients without side effects. In the "nonresistant" but intolerant group of patients, use of the combination allowed relief of symptomatic ectopy without side effects. A theoretical model correctly predicted an effective combination of class I antiarrhythmic drugs, one with "fast-off" and one with "slow-off" kinetics, which may provide a general rationale for choosing drug combinations.

Full Text

Duke Authors

Cited Authors

  • Nesterenko, VV; Anyukhovsky, EP; Bugrij, EM; Starmer, CF; Beloshapko, GG; Makielski, JC; Kuzmin, AV; Menshikov MJu, ; Mazaev, AV; Rosenshtraukh, LV

Published Date

  • March 1994

Published In

Volume / Issue

  • 23 / 3

Start / End Page

  • 501 - 508

PubMed ID

  • 7515997

Pubmed Central ID

  • 7515997

Electronic International Standard Serial Number (EISSN)

  • 1533-4023

International Standard Serial Number (ISSN)

  • 0160-2446

Language

  • eng