to correlate changes in pacemaker frequency with those of length and tension in mammalian atrial tissues , a strip of the sinoatrial ( sa ) nodal tissue ( about 10 mm in length and 4 mm in width ) isolated from the rabbit heart was subjected to constant-length and constant-load stretches , and the relation between the resulting pacemaker frequency changes and the segmental length changes of the preparation was examined by means of cinematographic recording of the preparation with carbon markers on its surface .
C0018792
atrial
C0018787
heart