Differentiation of the Electrophysiological Effects on the Atrial Myocardium Between the Pure Na Channel Blocker, Pilsicainide, and Flecainide
Authors: Masashi Kanemoto1; Akihiko Shimizu1; Toshihiko Yamagata1; Masahiro Esato1; Takeshi Ueyama1; Yasuhiro Yoshiga1; Hiroyuki Kakugawa1; Ryousuke Kametani1; Noriko Inoue1; Akira Sawa1; Masunori Matsuzaki2
Source: Cardiovascular Drugs and Therapy, Volume 18, Number 4, July 2004 , pp. 295-303(9)
Publisher: Springer
Abstract:
The purpose of this study was to identify the difference between the pure Na channel blocker, pilsicainide and Ic-antiarrhythmic drug, flecainide, on the atrial electrophysiological characteristics.Methods: The subjects consisted of 24 patients (48 ± 12 years-old: P-group) in whom pilsicainide was administrated intravenously (1 mg/kg/10 min) and 31 patients (47 ± 15 years-old: F-group) in whom flecainide was administrated intravenously (2 mg/kg/10 min). The atrial effective refractory period (ERP-A), intra-atrial conduction time (CT), max intra-atrial conduction delay (Max CD), repetitive atrial firing zone (RAFZ), fragmented atrial activity zone (FAZ) and intra-atrial conduction delay zone (CDZ) were measured before and after the drugs.Results: Pilsicainide and flecainide significantly prolonged the ERP-A (211 ± 27 msec to 246 ± 39 msec; p < 0.001, 217 ± 25 msec to 244 ± 33 msec; p < 0.001, respectively) and CT (121 ± 33 msec to 149 ± 43 msec; p < 0.001, 122 ± 22 msec to 153 ± 27 msec; p < 0.001, respectively) to the same degree. However, the Max CD was shortened by pilsicainide, but not by flecainide. The RAFZ, FAZ and CDZ decreased in the P-group (21 ± 25 msec to 4 ± 10 msec; p < 0.01, 24 ± 24 msec to 14 ± 18 msec; p < 0.05, 56 ± 29 msec to 43 ± 32 msec, p < 0.05, respectively), but not in the F-group. Conclusions: The effects of atrial conduction delays may differ between pilsicainide and flecainide. Further examination will be needed to explain this mechanism.Keywords: sodium channel blocker; pilsicainide; flecainide; antiarrhythmic drug; atrial vulnerability
Document Type: Research article
DOI: 10.1023/B:CARD.0000041249.35724.da
Affiliations: 1: Division of Cardiovascular Medicine, Yamaguchi University Graduate School of Medicine 2: Division of Cardiovascular Medicine, Yamaguchi University Graduate School of Medicine, Email: masunori@yamaguchi-u.ac.jp

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