Effects of oral disopyramide phosphate on induction and sustenance of atrioventricular reentrant tachycardia incorporating retrograde accessory pathway conduction.

We evaluated the effects of oral disopyramide on induction and sustenance of AV reentrant tachycardia incorporating a retrogradely conducting accessory pathway in a large group of patients

H C Kou; J S Hung; Y S Lee; D Wu

2011

Scholarcy highlights

  • Oral disopyramide phosphate is effective in preventing induction of sustained AV reentrant tachyeardia in most patients
  • We evaluated the effects of oral disopyramide on induction and sustenance of AV reentrant tachycardia incorporating a retrogradely conducting accessory pathway in a large group of patients
  • Sustained AV reentrant tachycardia was induced in all 20 patients during the control study
  • In 14 patients, the tachycardia was induced by rapid atrial pacing, in 16 patients by atrial extrastimulus testing with demonstration of an antegrade echo zone, in 12 patients by rapid ventricular pacing, and in two patients by ventricular extrastimulus testing with demonstration of a retrograde echo zone
  • Antegrade induction of tachycardia was related to the achievement of a critical AV conduction time either with rapid atrial pacing or with atrial extrastimulus testing
  • Oral disopyramide prevented induction and sustenance of tachycardia in a majority of patients primarily because of the increased retrograde refractory period of the accessory pathway. This observation is substantiated by inability to induce AV reentrant atrial echo or tachycardia after disopyramide despite an AV interval longer than the critical AV interval during the control study; spontaneous termination of the induced tachycardia after disopyramide with a QRS complex not followed by an atrial response; and the ventricular paced cycle length that produced VA block after disopyramide being longer than the cycle length of the tachycardia
  • We suggest diagnostic criteria of parasystolic modulation

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