Simultaneous recording of action potentials from endocardium and epicardium during ischemia in the isolated cat ventricle: relation of temporal electrophysiologic heterogeneities to arrhythmias.

摘要: We studied the effects of ischemia on transmembrane action potentials, conduction time, and refractory periods both endocardial epicardial muscle cells coronary-perfused cat left ventricles. Oxygenated Tyrode's solution was perfused through anterior descending coronary artery, while preparation superfused with gassed 95% N2 5% CO2. Transmembrane potentials recorded simultaneously from were normal during perfusion. When perfusion discontinued ("ischemia"), rapid deterioration prolongation time observed in cells. The magnitude reduction potential amplitude duration (APD), greater than cells, although change resting membrane almost same. However, APD decreased progressively 30 min ischemia, whereas reduced maximally at 10 then partially recovered. Shortening paralleled shortening, for first increased. At significantly shorter those exceeded because development postrepolarization refractoriness Accompanying these different changes spontaneous extrasystolic impulses increased runs could be induced by extrastimuli.(ABSTRACT TRUNCATED AT 250 WORDS)