[Effects of oxymatrine on arrhythmia in dogs with myocardial infarction].
OBJECTIVE
To study the effects of oxymatrine (Oxy) on arrhythmia in dogs with myocardial infarction.


METHODS
Partly ligating the left anterior descending coronary artery in the open-chest dogs produced myocardial infarction of left anterior ventricular wall. After 5-8 d, the diastolic excitability threshold (DET), the effective refractory periods (ERP) and arrhythmias were determined by programmed electric stimulation (PES).


RESULTS
Oxy (i.v. 50 mg.kg-1) increased DET from 2.53 +/- 1.28 to 3.19 +/- 1.62 V, lengthened ERP from 182 +/- 25 to 219 +/- 43 ms at normal region and from 206 +/- 49 to 235 +/- 55 ms at infarct region in left ventricle, but had no effects on dispersion of ERP, QTc interval and ventricular tachycardia (VT) or ventricular fibrillation (VF). Procainamide (Pro) (i.v. 25 mg.kg-1) increased DET and lengthened ERP and QTc interval, but decreased the dispersion of ERP. Pro prevented PES-induced VT/VF and spontaneous ischemia-related VF.


CONCLUSIONS
The increased DET and lengthened ERP of Oxy are its anti-arrhythmic mechanism.
Zeng
J X
JX
Department of Cardiovascular Disease, First Affiliated Hospital, Jiangxi Medical College, Nanchung, China.
Cao
H Y
HY
Li
Q
Q
Xu
Z
Z
Guo
Z B
ZB
D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D001145:Arrhythmias, Cardiac / Q000517:prevention & control*; D004285:Dogs; D005260:Female; D008297:Male; D009203:Myocardial Infarction / Q000503:physiopathology*; D011807:Quinolizines; D012032:Refractory Period, Electrophysiological / Q000187:drug effects; D000093842:Matrines
D000470:Alkaloids; D000889:Anti-Arrhythmia Agents; D011807:Quinolizines; C037573:oxymatrine; D000093842:Matrines