Differential effects of quinidine on transmembrane action potentials of normal and infarcted canine Purkinje fibers.

摘要: Fourteen days after proximal ligation of the left anterior descending coronary artery (LAD) mongrel dogs, effects quinidine on action potentials normal and infarcted Purkinje fibers were evaluated. The concentration-dependent (10(-7)-3 x 10(-5) M) frequency-dependent (1 3 Hz) actions evaluated by following parameters: maximum upstroke velocity (Vmax), potential duration at 50 95% repolarization (APD50, APD95), effective refractory period (ERP), resting membrane (RMP), amplitude (APA). Quinidine reduced Vmax in abnormal a concentration- manner; these more pronounced tissue. APD50 was shortened significantly 1 Hz noninfarcted fibers, whereas had no effect APD50. APD95 not altered fibers; areas prolonged Hz. (ERP) marked ischemically damaged fibers. No observed (RMP). APA Hz; there difference between These data indicate differential which may be an important mechanism