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 [(125)I]metaiodobenzylguanidine and (99m)Tc-sestamibi. ARIs were recorded during baseline sinus rhythm, norepinephrine (NE) infusion (0.1 microg. 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, with increased shortening and dispersion related to increased severity of denervation (P<0.01). SS prolonged ARI in 70% of electrodes in the denervated area, with no correlation with severity of denervation. CONCLUSIONS: The magnitude and dispersion of local repolarization responses are related to the severity of denervation, as well as the type of stimulation: neural (SS) versus humoral (NE). The differences may relate to the concentration of NE released.
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 [(125)I]metaiodobenzylguanidine and (99m)Tc-sestamibi. ARIs were recorded during baseline sinus rhythm, norepinephrine (NE) infusion (0.1 microg. 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, with increased shortening and dispersion related to increased severity of denervation (P<0.01). SS prolonged ARI in 70% of electrodes in the denervated area, with no correlation with severity of denervation. CONCLUSIONS: The magnitude and dispersion of local repolarization responses are related to the severity of denervation, as well as the type of stimulation: neural (SS) versus humoral (NE). The differences may relate to the concentration of NE released.
Authors: Marmar Vaseghi; Nicolas Lellouche; Harry Ritter; Gregg C Fonarow; Jignesh K Patel; Jaime Moriguchi; Michael C Fishbein; Jon A Kobashigawa; Kalyanam Shivkumar Journal: Heart Rhythm Date: 2009-01-16 Impact factor: 6.343
Authors: M E Marketou; E N Simantirakis; V K Prassopoulos; S I Chrysostomakis; A A Velidaki; N S Karkavitsas; P E Vardas Journal: Heart Date: 2002-09 Impact factor: 5.994