Effects of amiodarone on wave front dynamics during ventricular fibrillation in isolated swine right ventricle.
The effects of acute amiodarone infusion on dynamics of ventricular fibrillation (VF) are unclear. Six isolated swine right ventricles (RVs) were studied in vitro. Activation patterns during VF were mapped optically, whereas action potentials were recorded with a glass microelectrode. At baseline, VF was associated with frequent spontaneous wave breaks. Amiodarone (2.5 microg/ml) reduced spontaneous wave breaks and increased the cycle length (CL) of VF from 83.3 +/- 17.8 ms at baseline to 118.4 +/- 25.8 ms during infusion (P < 0.05). Amiodarone increased the reentrant wave front CL (114.4 +/- 15.5 vs. 78.2 +/- 19.0 ms, P < 0.05) and central core area (4.1 +/- 3.8 vs. 0.9 +/- 0.3 mm2, P < 0.05). Within 30 min of infusion, VF terminated (n = 1), converted to ventricular tachycardia (VT) (n = 1) or continued at a slower rate (n = 4). Amiodarone flattened the APD restitution curves. We conclude that amiodarone reduced spontaneous wave breaks. It might terminate VF or convert VF to VT. These effects were associated with the flattening of APD restitution slope and increased core size of reentrant wave fronts.
Omichi
Chikaya
C
Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, University of California at Los Angeles School of Medicine, Los Angeles, California 90048-1865, USA.
Zhou
Shengmei
S
Lee
Moon-Hyoung
MH
Naik
Ajay
A
Chang
Che-Ming
CM
Garfinkel
Alan
A
Weiss
James N
JN
Lin
Shien-Fong
SF
Karagueuzian
Hrayr S
HS
Chen
Peng-Sheng
PS
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000638:Amiodarone / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D003971:Diastole / Q000187:drug effects; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D013552:Swine; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000503:physiopathology*; D016278:Ventricular Function, Right / Q000187:drug effects / Q000502:physiology*
D000889:Anti-Arrhythmia Agents; D000638:Amiodarone