Effect of Autonomic Nervous System on the Transmural Dispersion of Ventricular Repolarization in Intact Canine

The effect of the autonomic nerves on the transmural dispersion ot ventrtcular repolartzation in intact canine was investigated. By using the monophasic action potential (MAP) recording technique, monophasic action potentials (MAPs) of the epicardium (Epi), midmyocardium (Mid) and endocardium (Endo) were recorded simultaneously by specially designed plunge-needle electrodes at the left ventricular free wall in 12 open-chest dogs. MAPD90 and transmural dispersion of repolarization among three myocardial layers as well as the incidence of the EAD before autonomicnervous stimulation and during autonomic nervous stimulation were compared. The results showed that the MAPD90 of Epi, Mid and Endo before autonomic nervous stimulation were 278 + 11 ms,316±16 ms and 270±12 ms respectively, the MAPD90 of Mid was significantly longer than that of Epi or Endo (P