Systolic (ST) current flow across infarct boundaries

Dissimilarities in the electrophysiological abnormalities of lateral border and central infarct zone cells after healing of myocardial infarction in cats.

“…These data indicate that conduction was impaired in the border zone, whereas normal conduction was still possible in central infarct and normal areas. The electrophysiological abnormalities in the endocardial lateral border zone cells of the healed myocardial infarction appear to be the most severe, and the border zone may play an important role in chronic electrophysiological instability observed both in situ and in vitro (Circ Res 51: 486-193, 1982) DURING acute ischemia and early infarction, a border zone composed of damaged but viable myocardium surrounding a central zone of irreversible injury or infarction has been identified ultrastructurally (Cox et al, 1968;Page and Polimeni, 1977;Kloner et al, 1979), histochemically (Fishbein et al, 1980), and electrophysiologically (Kleber et al, 1978;Anderson et al, 1980). Hearse et al (1977), in a recent study of acute ischemia in the dog, described a border zone of reduced blood flow, elevated lactate, and sharply decreased high energy phosphate content.…”

“…A gradual change in electrical potential from normal to ischemic tissues has been observed in acutely ischemic pig hearts (Kleber et al, 1978). Anderson et al (1980) demonstrated marked variations in electrophysiological responses developed in normal, border, and infarct zones after acute coronary occlusion. Although these studies have generated considerable information on the characteristics of border zone cells in acute experimental ischemia, few data are available on the border zone of healing or healed myocardial infarction.…”