Intracardiac electrical stimulation of parasympathetic nerve fibers induced a negative dromotropic effect that was abolished by atropine but preserved after successful radiofrequency ablation.
Does intracardiac electrical stimulation of parasympathetic nerve fibers induce negative dromotropic effects, and are these effects preserved after radiofrequency ablation?
Intracardiac parasympathetic stimulation induces negative dromotropic effects that are vagally mediated and remain intact after standard radiofrequency ablation for AVNRT or atrial flutter.
INTRODUCTION: The dromotropic effects of intracardiac parasympathetic nerve stimulation have not been well studied; furthermore, the effects of radiofrequency ablation lesions on parasympathetic nerve stimulation are not clear. METHODS AND RESULTS: Group I: intracardiac electrical stimulation in the right posteroseptal and anteroseptal areas under different stimulation strengths; group II: intracardiac electrical stimulation before and 10 minutes after intravenous propranolol; group III: intracardiac electrical stimulation before and 5 minutes after intravenous atropine. Among the 10 patients with AV nodal reentrant tachycardia (group IV) and the 10 patients with atrial flutter (group V), atrial fibrillation was induced before and after successful ablation, and intracardiac electrical stimulation in the right posteroseptal area was performed before and after successful ablation. The maximal response and complete decay of the response occurred within 2 to 6 seconds of initiation or termination of parasympathetic nerve stimulation. This negative dromotropic effect disappeared after atropine was administered, but not after propranolol. After successful ablation, parasympathetic stimulation still induced negative dromotropic effects. CONCLUSION: Electrical stimulation of parasympathetic nerve fibers near the posteroseptal and anteroseptal areas could induce a negative dromotropic effect, and this effect was preserved after successful radiofrequency ablation of slow pathway and isthmus conduction.
Chen et al. (Sun,) conducted a other in AV nodal reentrant tachycardia and atrial flutter. Intracardiac electrical stimulation of parasympathetic nerve fibers vs. Baseline, post-pharmacologic blockade, and post-ablation was evaluated on Negative dromotropic effect. Intracardiac electrical stimulation of parasympathetic nerve fibers induced a negative dromotropic effect that was abolished by atropine but preserved after successful radiofrequency ablation.