In-vitro and in-vivo electrophysiologic effects of encainide

Cardiovascular Drugs and Therapy
C C LibersaR Rouet

Abstract

The intracellular electrophysiologic effects of encainide (E) and its main metabolite, O-desmethyl-encainide (ODE), were studied in guinea-pig papillary muscle preparations and related to the in-vivo electrophysiologic effects observed after intravenous (IV) infusion of E in 11 patients undergoing electrophysiologic study (EPS). At equipotent concentrations of E and ODE, frequency-dependent reductions in Vmax studied at pacing rates of 30-180 beats/min ranged from -11.5% to -53%, with maximum reductions of -53% and -47%, respectively at the highest frequency. The kinetics of onset of use-dependent Vmax reduction were slower for ODE than for E at each studied pacing rate. The kinetics of total recovery from use-dependent block were still slower (120 seconds for E and 300 seconds for ODE at a 90 beats/min pacing rate). These in-vitro electrophysiologic data could explain the marked alterations in intraventricular and atrioventricular conduction observed in humans 60 minutes after IV administration of 1 mg/kg of E over a 15-minute period. The QRS, PA, AH, and HV intervals were significantly increased (p less than 0.01) and the Wenckebach cycle length was increased by 8% (p less than 0.05). Blood pressure, RR, QT, CSNRT, ESACT, ERP...Continue Reading

References

Nov 1, 1985·Journal of Cardiovascular Pharmacology·C C LibersaA R Kher
Apr 1, 1984·Journal of Clinical Pharmacology·E M Vaughan Williams
Jan 1, 1984·Annual Review of Pharmacology and Toxicology·L M Hondeghem, B G Katzung
Apr 1, 1982·The American Journal of Cardiology·W M JackmanE N Prystowsky

❮ Previous
Next ❯

Citations

Dec 1, 1992·Hypertension·C L Jackson, S M Schwartz

❮ Previous
Next ❯

Related Concepts

Related Feeds

Cardiac Conduction System

The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Discover the latest research on the cardiac conduction system here.