Eitaro Fujii

Radiofrequency (RF) catheter ablation of supraventricular tachycardias causes local parasympathetic denervation. This study used heart rate variability (HRV) to evaluate the effects of ablation of atrial tachycardia (AT) arising from the atrioventricular annulus (AVAT) on autonomic function. Ten patients with AVAT were referred for ablation (group AT) and compared with 8 patients with paroxysmal atrial fibrillation who underwent PV isolation (group Paf), and 13 patients with idiopathic ventricular tachycardia successfully treated by ablation (group VT). Time and frequency domain analysis of HRV on 24‐hour ambulatory ECG recordings was performed before and after ablation. Root mean square of differences of consecutive N‐N intervals (rMSSD), percentage of difference between consecutive N‐N intervals >50 ms (pNN50), and high frequency (HF) component were measured to examine the effects on parasympathetic nerve activity. In group AT, rMSSD, pNN50, and HF decreased significantly after ablation, while they remained unchanged in group Paf and group VT. These observations suggest that parasympathetic denervation after ablation was limited to group AT, and depended on the site of energy delivery along the tricuspid or mitral valve as opposed to atrial or ventricular muscle.

A 39-year-old Japanese woman presented with an idiopathic left ventricular aneurysm manifesting as recurrent episodes of palpitation. She was referred to our hospital for evaluation of sustained ventricular tachycardia. Echocardiography disclosed a dyskinetic well-defined wall bulge during both systole and diastole at the basal region of the interventricular septum, and reduced left ventricular wall thickness and severe hypokinesis at the anterolateral to posterolateral region. These appearances were confirmed by the angiographic findings. The sustained ventricular tachycardia was reproducibly induced by a single extrastimulus from the right ventricular apex. Subsequently, 4-type ventricular tachycardias were induced during the electrophysiological study and the mechanism of these ventricular tachycardias was considered reentry. Radiofrequency catheter ablation failed due to the changing QRS morphologies during the entrainment study. The patient was treated with cibenzoline 300 mg a day, and there has been no recurrence of tachycardia during the 18-month follow-up period.