title: A new electrocardiographic marker for sympathetic nerve stimulation: modulation of repolarization by stimulation of stellate ganglia.
abstract: Activation of cardiac sympathetic nerves alters ventricular repolarization; however, these changes remain poorly characterized. The goal of this study was to examine effects of sympathetic stimulation on repolarization to identify electrocardiographic markers of sympathetic activation. Pigs underwent median sternotomy and bilateral thoracotomy to expose the stellate ganglia. Changes in T-wave duration, amplitude, repolarization vector, and time from peak to end (Tp-Te) were continuously monitored. Within 15 seconds of unilateral left or right stellate ganglion (LSG/RSG) stimulation, T-wave amplitude increased 6- and 4.5-fold, respectively, in lead aVF. T-wave duration and Tp-Te both increased 200% during LSG stimulation but only 50% and 30%, respectively, with RSG stimulation. During LSG stimulation, frontal and horizontal T-wave vectors, respectively, changed from 1.9° ± 22.8° and 333.8° ± 9.7° at baseline to 83.4° ± 3.9° (inferiorly) and 306.7° ± 1.8° (posteriorly). During RSG stimulation, frontal and horizontal T-wave vectors changed from 348.2° ± 21.6° and 333.8° ± 10.3° before stimulation to 280.7° ± 4.6° (superiorly) and 118.1° ± 5.6° (anteriorly). During stellate stimulation, T-wave vectors are displaced to angles specific for LSG activation (posteroinferiorly) or RSG activation (anterosuperiorly); T-wave amplitude, duration, and Tp-Te increase; and ST-duration decreases. Displaced repolarization vector and changes in T-wave morphometrics provide a novel marker of unilateral sympathetic nerve stimulation.
authors.affiliation: UCLA Cardiac Arrhythmia Center, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-7403, USA.
authors.forename: Rafael J
authors.initials: RJ
authors.lastname: Ramirez
authors.forename: Olujimi A
authors.initials: OA
authors.lastname: Ajijola
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.forename: Björn
authors.initials: B
authors.lastname: Holmström
authors.forename: Hampus
authors.initials: H
authors.lastname: Lüning
authors.forename: Michael M
authors.initials: MM
authors.lastname: Laks
authors.forename: Kalyanam
authors.initials: K
authors.lastname: Shivkumar
authors.forename: Aman
authors.initials: A
authors.lastname: Mahajan
mesh_terms: D000818:Animals; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology; D013233:Stellate Ganglion / Q000502:physiology*; D013552:Swine; D017779:Sympathetic Fibers, Postganglionic / Q000502:physiology; D013564:Sympathetic Nervous System / Q000502:physiology*; D014672:Vectorcardiography