Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9171697 | Journal of Electrocardiology | 2005 | 5 Pages |
Abstract
Differential effects of sodium channel blockers, an IKr blocker (nifekalant) and amiodarone on the spiral-type reentry, were investigated in rabbit hearts by using a high-resolution optical mapping system. Two-dimensional subepicardial layer of left ventricular myocardium with uniform anisotropy was prepared by endocardial cryoablation. During ventricular tachycardia (VT) elicited by cross-field stimulation, spiral-type excitations rotating around functional block lines (FBLs) were visualized. All the sodium channel blockers stabilized rotors; VT duration was prolonged in association with increases of FBLs and VT cycle length. The rotors in the presence of nifekalant were characterized by large meandering, long FBLs, and frequent front-tail interactions generating wave breaks. Amiodarone (acute application) increased FBLs and VT cycle length, but shortened the VT duration with minimal front-tail interaction. These results suggest that multifaceted drug action on both depolarization and repolarization may be required for the early termination of spiral-type reentry without causing breakup of rotors.
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Authors
Itsuo MD, Haruo MD, Mastoshi MD, Harumichi MD, Yuko MD, Yusuke Okuno, Ichiro PhD, Kaichiro MD,