TY - JOUR
T1 - Effects of quinidine on arrhythmias and conduction in an isolated tissue model of ischemia and reperfusion
AU - Li, Gui Rong
AU - Ferrier, Gregory R.
PY - 1991/2
Y1 - 1991/2
N2 - Transmembrane electrical activity from endoand epicardium and a high-gain ECG were recorded from isolated segments of guinea pig right ventricles. Endocardium was stimulated. Tissues were exposed to ischemic conditions for 15 min and then reperfused with ±normal± Tyrode's solution. Ventricular tachycardia, bigeminy, or trigeminy with characteristics of transmural reentry occurred in early reperfusion in 68% of control hearts. Arrhythmias were associated with prolongation of the transmural conduction time (CT) and abbreviation of the endocardial effective refractory period (EP). Quinidine significantly suppressed reperfusion arrhythmias at 1 and 5 μM, slightly increased the incidence of arrhythmias at 10 μM, and again suppressed arrhythmias at 50 and 100 μM. At 1 and 5 μM, quinidine prevented or attenuated prolongation of the transmural CT by ischemic conditions and reperfusion. The transmural CT was not significantly changed at 10 μM, and was further prolonged at 50 and 10 μM quinidine. The endocardial ERP was prolonged by 50 and 100 μM quinidine during ischemic conditions and reperfusion. In epicardial slices, 5 μM quinidine shortened the CT transverse to the fiber orientation during reperfusion but had no effect on the longitudinal CT. Thus, antiarrhythmic efficacy of low concentrations of quinidine may occur through differential effects dependent on tissue anisotropy.
AB - Transmembrane electrical activity from endoand epicardium and a high-gain ECG were recorded from isolated segments of guinea pig right ventricles. Endocardium was stimulated. Tissues were exposed to ischemic conditions for 15 min and then reperfused with ±normal± Tyrode's solution. Ventricular tachycardia, bigeminy, or trigeminy with characteristics of transmural reentry occurred in early reperfusion in 68% of control hearts. Arrhythmias were associated with prolongation of the transmural conduction time (CT) and abbreviation of the endocardial effective refractory period (EP). Quinidine significantly suppressed reperfusion arrhythmias at 1 and 5 μM, slightly increased the incidence of arrhythmias at 10 μM, and again suppressed arrhythmias at 50 and 100 μM. At 1 and 5 μM, quinidine prevented or attenuated prolongation of the transmural CT by ischemic conditions and reperfusion. The transmural CT was not significantly changed at 10 μM, and was further prolonged at 50 and 10 μM quinidine. The endocardial ERP was prolonged by 50 and 100 μM quinidine during ischemic conditions and reperfusion. In epicardial slices, 5 μM quinidine shortened the CT transverse to the fiber orientation during reperfusion but had no effect on the longitudinal CT. Thus, antiarrhythmic efficacy of low concentrations of quinidine may occur through differential effects dependent on tissue anisotropy.
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U2 - 10.1097/00005344-199102000-00009
DO - 10.1097/00005344-199102000-00009
M3 - Article
C2 - 1709228
AN - SCOPUS:0025972947
SN - 0160-2446
VL - 17
SP - 239
EP - 248
JO - Journal of Cardiovascular Pharmacology
JF - Journal of Cardiovascular Pharmacology
IS - 2
ER -