Role of the Alternans of Action Potential Duration and Aconitine-Induced Arrhythmias in Isolated Rabbit Hearts
- Author(s)
- Byung-Chun Jung; Sang-Hee Lee; Yong-Keun Cho; Hyoung-Seob Park; Yoon-Nyun Kim; Young-Soo Lee; Dong-Gu Shin
- Keimyung Author(s)
- Park, Hyoung Seob; Kim, Yoon Nyun
- Department
- Dept. of Internal Medicine (내과학)
- Journal Title
- Journal of Korean Medical Science
- Issued Date
- 2011
- Volume
- 26
- Issue
- 12
- Keyword
- Aconitine; Optical mapping; APD restitution; APD alternans
- Abstract
- Under conditions of Na+ channel hyperactivation with aconitine, the changes in action
potential duration (APD) and the restitution characteristics have not been well defined in
the context of aconitine-induced arrhythmogenesis. Optical mapping of voltage using
RH237 was performed with eight extracted rabbit hearts that were perfused using the
Langendorff system. The characteristics of APD restitution were assessed using the steadystate
pacing protocol at baseline and 0.1 μM aconitine concentration. In addition, pseudo-
ECG was analyzed at baseline, and with 0.1 and 1.0 μM of aconitine infusion respectively.
Triggered activity was not shown in dose of 0.1 μM aconitine but overtly presented in 1.0
μM of aconitine. The slopes of the dynamic APD restitution curves were significantly
steeper with 0.1 μM of aconitine than at baseline. With aconitine administration, the cycle
length of initiation of APD alternans was significantly longer than at baseline (287.5 ± 9.6
vs 247.5 ± 15.0 msec, P = 0.016). The functional reentry following regional conduction
block appears with the progression of APD alternans. Ventricular fibrillation is induced
reproducibly at pacing cycle length showing a 2:1 conduction block. Low-dose aconitine
produces arrhythmogenesis at an increasing restitution slope with APD alternans as well as
regional conduction block that proceeds to functional reentry.
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