title: Focal myocardial infarction induces global remodeling of cardiac sympathetic innervation: neural remodeling in a spatial context.
abstract: Myocardial infarction (MI) induces neural and electrical remodeling at scar border zones. The impact of focal MI on global functional neural remodeling is not well understood. Sympathetic stimulation was performed in swine with anteroapical infarcts (MI; n = 9) and control swine (n = 9). A 56-electrode sock was placed over both ventricles to record electrograms at baseline and during left, right, and bilateral stellate ganglion stimulation. Activation recovery intervals (ARIs) were measured from electrograms. Global and regional ARI shortening, dispersion of repolarization, and activation propagation were assessed before and during sympathetic stimulation. At baseline, mean ARI was shorter in MI hearts than control hearts (365 ± 8 vs. 436 ± 9 ms, P < 0.0001), dispersion of repolarization was greater in MI versus control hearts (734 ± 123 vs. 362 ± 32 ms(2), P = 0.02), and the infarcted region in MI hearts showed longer ARIs than noninfarcted regions (406 ± 14 vs. 365 ± 8 ms, P = 0.027). In control animals, percent ARI shortening was greater on anterior than posterior walls during right stellate ganglion stimulation (P = 0.0001), whereas left stellate ganglion stimulation showed the reverse (P = 0.0003). In infarcted animals, this pattern was completely lost. In 50% of the animals studied, sympathetic stimulation, compared with baseline, significantly altered the direction of activation propagation emanating from the intramyocardial scar during pacing. In conclusion, focal distal anterior MI alters regional and global pattern of sympathetic innervation, resulting in shorter ARIs in infarcted hearts, greater repolarization dispersion, and altered activation propagation. These conditions may underlie the mechanisms by which arrhythmias are initiated when sympathetic tone is enhanced.
authors.affiliation: University of California-Los Angeles (UCLACardiac Arrhythmia Center, UCLA, Los Angeles, California;
authors.forename: Olujimi A
authors.initials: OA
authors.lastname: Ajijola
authors.forename: Daigo
authors.initials: D
authors.lastname: Yagishita
authors.forename: Krishan J
authors.initials: KJ
authors.lastname: Patel
authors.forename: Marmar
authors.initials: M
authors.lastname: Vaseghi
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamakawa
authors.forename: Eileen
authors.initials: E
authors.lastname: So
authors.forename: Robert L
authors.initials: RL
authors.lastname: Lux
authors.forename: Aman
authors.initials: A
authors.lastname: Mahajan
authors.forename: Kalyanam
authors.initials: K
authors.lastname: Shivkumar
mesh_terms: D000818:Animals; D056988:Anterior Wall Myocardial Infarction / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D004195:Disease Models, Animal; D004558:Electric Stimulation; D022062:Electrophysiologic Techniques, Cardiac; D006321:Heart / Q000294:innervation*; D009206:Myocardium / Q000473:pathology*; D013233:Stellate Ganglion / Q000503:physiopathology*; D013552:Swine; D013997:Time Factors
keywords: autonomic nervous system; cardiac innervation; neural remodeling; sympathetic nerves
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