Transverse propagation resulted in significantly greater maximum rate of rise of transmembrane potential (Vmax) compared to longitudinal propagation in canine ventricular muscle (P < 0.001).
Does the direction of propagation alter the maximum rate of rise of transmembrane potential (Vmax) in canine ventricular muscle cells?
Cellular Vmax is sensitive to the direction of propagation, reflecting the electrical load presented by adjoining cells.
p-value: p=< 0.001
This study was designed to test the hypothesis that the electrical load seen at a microelectrode impalement site is sensitive to the direction of propagation of the approaching wavefront as a reflection of an altered spatial relationship between the impalement site and the surrounding microscopic electrical boundaries located up- and downstream. These boundaries correspond to the different sizes and shapes of the impaled and surrounding cells as well as to the distribution of the associated electrical connections between the cells. The effects of changes in these geometric relationships on maximum rate of rise of transmembrane potential (Vmax) were investigated in canine ventricular muscle by measuring Vmax in different cells while the direction of propagation was changed from along the longitudinal axis to the transverse axis of the fibers or the direction of conduction was reversed along either of these axes. Comparison of the Vmax values for longitudinal propagation (LP) and transverse propagation (TP), each in one direction, showed that TP Vmax was significantly greater than LP Vmax (P < 0.001). However, the values of Vmax were different from cell to cell during LP (93-139 V/s) and TP (110-181 V/s). The absolute values of LP Vmax and TP Vmax at the same site varied independently of each other, e.g., some of the lowest LP Vmax values occurred at the same site as the highest TP Vmax values. Furthermore, at the same site, Vmax changed considerably when propagation was maintained along the longitudinal axis but the direction of conduction was reversed. Similar prominent changes in Vmax occurred when the direction was reversed along the transverse axis.(ABSTRACT TRUNCATED AT 250 WORDS)
Spach et al. (Tue,) conducted a other in Canine ventricular muscle electrophysiology. Transverse propagation (TP) vs. Longitudinal propagation (LP) was evaluated on Maximum rate of rise of transmembrane potential (Vmax) (p=< 0.001). Transverse propagation resulted in significantly greater maximum rate of rise of transmembrane potential (Vmax) compared to longitudinal propagation in canine ventricular muscle (P < 0.001).
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