Heterogeneous Sympathetic Innervation Influences Local Myocardial Repolarization in Normally Perfused Rabbit Hearts

Background—Heterogeneity of sympathetic innervation is thought to contribute to the potential for fatal arrhythmia. However, little is known about the effects of heterogeneous innervation on repolarization. Methods and Results—To assess this relationship, we measured activation recovery intervals (ARIs) from 64 epicardial sites in 11 rabbits studied 2 weeks after regional denervation produced by phenol and 4 sham-operated rabbits. ARI results were compared with the distribution of sympathetic innervation measured from 3D reconstructions of serial autoradiographs of [125I]metaiodobenzylguanidine and 99mTc-sestamibi. ARIs were recorded during baseline sinus rhythm, norepinephrine (NE) infusion (0.1 μg · kg−1 · min−1), and left stellate ganglion stimulation (SS). NE shortened ARI in 98% of electrodes in the denervated region. The degree of ARI shortening and dispersion increased (P<0.001 and P<0.01, respectively) as denervation became more severe. SS shortened ARI in 30% of electrodes in the denervated area,...