Preferential action of mexiletine on central common pathway of reentrant ventricular tachycardia

Journal of the American College of Cardiology
Y AizawaS Fujita

Abstract

The action of mexiletine on diseased myocardium was assessed in reentrant ventricular tachycardia (VT). Whether class Ib antiarrhythmic agents exert a preferential action on the central common pathway of reentrant ventricular tachycardia has not yet been studied in humans. In 10 consecutive patients (7 with a previous myocardial infarction, 3 with nonischemic disease), VT was induced and entrained with rapid pacing. The orthodromic conduction time was measured from stimulus to the entrained electrogram at the exit from the presumed central common pathway (i.e., the earliest site of activation). Mexiletine at 125 to 250 mg was administered intravenously, and when VT with the same configuration was induced, the study was repeated. The action of mexiletine on the central common pathway was assessed from the changes in VT cycle length and orthodromic conduction time. The effects on QRS complex duration, local conduction time between the exit and the pacing site and duration of the local electrogram were compared between normal and diseased myocardium. Mexiletine prolonged the VT cycle length in all patients, from (mean +/- SD) 316 +/- 30 to 360 +/- 64 ms (mean change 20 +/- 7%, p < 0.001); during entrainment of VT, the orthodromic ...Continue Reading

References

May 1, 1978·The American Journal of Cardiology·R LazzaraB J Scherlag
Jan 1, 1989·Pacing and Clinical Electrophysiology : PACE·G FontaineY Grosgogeat
Aug 1, 1989·Journal of the American College of Cardiology·G N KayV J Plumb
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Nov 1, 1980·Journal of Molecular and Cellular Cardiology·K R Courtney
Jan 1, 1982·The American Journal of Cardiology·M E JosephsonA M Greenspan

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