Mapping of local conduction anisotropy in the ischemic myocardium

The effects of angiotensin II (Ang II), a modulator of cellular coupling, on impulse propagation in the ischemic myocardium were analyzed using maps of local conduction anisotropy. In control studies, ischemia causes a reduction in conduction velocities for both directions without significant changes for the anisotropic ratio. Before ischemia, Ang II induces an increase in the longitudinal direction but a decrease in the transversal direction. During ischemia, in the Ang II experiments conduction velocity slowed more rapidly and, reached slower conduction values for the transverse direction than in the controls. In conclusion, in the ischemic myocardium, Ang II enhances nonuniform anisotropy and hastens the development of conduction block. Thus, the therapeutic effect of ACE-inhibitors in patients with myocardial infarction may include an antiarrhythmic action