title: Edrophonium-induced right ventricular outflow tract tachycardia.
abstract: Idiopathic right ventricular outflow tract-ventricular tachycardia (RVOT-VT) generally occurs when sympathetic nervous system activity is increased, though, in a few patients, it develops when parasympathetic nervous activity (PNA) is increased. Among 101 consecutive patients with RVOT-VT confirmed by endocardial catheter mapping, 5 (4.9%) presented with nocturnal RVOT-VT. Autonomic nervous balance was studied by heart rate variability (HRV) analysis from 24-hour ambulatory electrocardiogram (ECG). Standard programmed ventricular stimulation (PVS), ventricular burst pacing, and drug provocation were performed to induce RVOT-VT. In the studied five patients, the average number of mostly nocturnal ventricular premature contractions (VPCs) was 6649 +/- 4472/day. Two patients had nocturnal nonsustained RVOT-VT on 24-hour ambulatory ECG recordings. The HRV analysis revealed that a progressive increase in high-frequency power coincided with an increase in VPCs or development of RVOT-VT at night, whereas low/high frequency ratio did not change significantly during the 24-hour period. RVOT-VT could not be induced by PVS, ventricular burst pacing, or isoproterenol or adenosine triphosphate i.v. However, RVOT-VT could only be induced by edrophonium, 5 mg i.v., in all patients. An increase in PNA was observed in a few patients before the development of RVOT-VT. Edrophonium facilitated induction of RVOT-VT in such patients.
authors.affiliation: Cardiology Department, Yokosuka Kyosai General Hospital, Kanagawa, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Hachiya
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma
authors.forename: Yasuteru
authors.initials: Y
authors.lastname: Yamauchi
authors.forename: Yukio
authors.initials: Y
authors.lastname: Sekiguchi
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Iesaka
mesh_terms: D000328:Adult; D000368:Aged; D002800:Cholinesterase Inhibitors / Q000009:adverse effects*; D004491:Edrophonium / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000139:chemically induced* / Q000503:physiopathology
chemical_list: D002800:Cholinesterase Inhibitors; D004491:Edrophonium