Optical imaging of spiral waves: pharmacological modification of spiral-type excitations in a 2-dimensional layer of ventricular myocardium.
Differential effects of sodium channel blockers, an I(Kr) 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.
Kodama
Itsuo
I
Department of Circulation, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Nagoya 464-8601, Japan. ikodama@riem.nagoya-u.ac.jp
Honjo
Haruo
H
Yamazaki
Mastoshi
M
Nakagawa
Harumichi
H
Ishiguro
Yuko
Y
Okuno
Yusuke
Y
Sakuma
Ichiro
I
Kamiya
Kaichiro
K
D000638:Amiodarone / Q000494:pharmacology; D000818:Animals; D016880:Anisotropy; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D006329:Heart Conduction System / Q000187:drug effects* / Q000473:pathology; D006801:Humans; D009206:Myocardium / Q000473:pathology*; D011226:Pre-Excitation Syndromes / Q000188:drug therapy* / Q000473:pathology*; D011744:Pyrimidinones / Q000494:pharmacology; D012815:Signal Processing, Computer-Assisted; D026941:Sodium Channel Blockers / Q000494:pharmacology*; D017180:Tachycardia, Ventricular / Q000188:drug therapy / Q000473:pathology
D000889:Anti-Arrhythmia Agents; D011744:Pyrimidinones; D026941:Sodium Channel Blockers; C076259:nifekalant; D000638:Amiodarone