canine cardiac purkinje fibers and atrial trabeculae and rat and cat papillary muscles superfused with a hyperkalemic , hypoxic , and acidotic tyrode solution were depolarized to membrane potentials ( -70 to -60 mv ) at which action potential amplitude declined as the coupling intervals of pacing stimuli were prolonged from 500 to 4,500 ms .
C0018787
cardiac
C0018792
atrial