XXXX and reperfusion: effects on subendocardial cardiac fibers.

@entity1563 @entity1188
Coronary flow and transmembrane potentials of Purkinje and muscle fibers in reperfused @entity1188 and @entity1188 caused by permanent @entity1563 were compared. Purkinje fibers in @entity1188 at 24 h had markedly reduced resting potentials. Action potential amplitudes, and Vmax were reduced and duration markedly prolonged. In reperfused @entity1188 , changes in Purkinje fiber transmembrane potentials were not as marked. Action potential duration in 3-day-old @entity1188 were longer than at 24 h, but in reperfused @entity1188 durations had returned to normal. Premature impulses conducted more rapidly in the reperfused infarct Purkinje system than in the permanently occluded. Other transmembrane potential parameters of Purkinje fibers in 3-day-old and 9- to 10-day-old reperfused and @entity1188 were not significantly different from each other. The ventricular muscle cells that survived in reperfused @entity1188 at all times also had reduced resting potentials and action potentials with decreased amplitudes, reduced Vmax, and prolonged durations. Almost no muscle cells survived in @entity1188 . Therefore, reperfusion salvages subendocardial fibers and prevents some but not all of the electrophysiological abnormalities.
