Reversal of electrophysiologic effects of flecainide on the accessory pathway by isoproterenol in the Wolff-Parkinson-White syndrome

The American Journal of Cardiology
A S Manolis, N A Estes

Abstract

To determine the reversibility of the effects of flecainide on accessory pathways, electrophysiologic studies were performed in the drug-free control state, after flecainide loading and with isoproterenol infusion during flecainide treatment in 12 patients with symptomatic preexcitation syndrome. After the baseline drug-free evaluation, oral flecainide was given in dosages of 50 to 200 mg twice daily (mean daily dose 282 +/- 75) for at least 4 days before the repeat electrophysiologic study. Isoproterenol infusion was given in dosages of 1 to 4 micrograms/min to increase the heart rate at rest by 50%. Anterograde block in the accessory pathway was observed in 3 patients with flecainide therapy, whereas in the other patients the anterograde refractory period increased from 243 +/- 20 to 315 +/- 23 ms (p less than 0.05). The shortest preexcited RR interval during atrial fibrillation lengthened from 234 +/- 27 ms before flecainide to 313 +/- 38 ms (p less than 0.05). Retrograde block occurred in 2 patients after flecainide, whereas the retrograde refractory period of the accessory pathway increased from 247 +/- 26 to 337 +/- 45 ms in the other patients. Orthodromic atrioventricular reciprocating tachycardia, inducible in 10 patien...Continue Reading

References

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Citations

Feb 1, 1992·Journal of the American College of Cardiology·H CalkinsF Morady
Jun 18, 1998·American Heart Journal·R WeissF Morady
Nov 1, 1994·Journal of Cardiovascular Electrophysiology·R H Falk, R I Fogel
Feb 1, 1996·Journal of Cardiovascular Electrophysiology·J M Miller
Sep 16, 1998·The American Journal of Cardiology·P T Sager
Aug 20, 1992·The American Journal of Cardiology·I Crozier
Sep 3, 2003·Journal of Cardiovascular Electrophysiology·Hiroshi TadaFred Morady
May 21, 2020·Trends in Cardiovascular Medicine·Antonis A ManolisAntonis S Manolis

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