Proarrhythmic proclivity of left-stellate ganglion stimulation in a canine model of drug-induced long-QT syndrome type 1

Rachel M.A. ter Bekke, Annerie M.E. Moers, Monique M.J. de Jong, Daniel M. Johnson, Peter J. Schwartz, Emilio Vanoli, Paul G.A. Volders

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Left-stellate ganglion stimulation (LSGS) can modify regional dispersion of ventricular refractoriness, promote triggered activity, and reduce the threshold for ventricular fibrillation (VF). Sympathetic hyperactivity precipitates torsades de pointes (TdP) and VF in susceptible patients with long-QT syndrome type 1 (LQT1). We investigated the electromechanical effects of LSGS in a canine model of drug-induced LQT1, gaining novel arrhythmogenic insights. Methods: In nine mongrel dogs, the left and right stellate ganglia were exposed for electrical stimulation. ECG, left- and right-ventricular endocardial monophasic action potentials (MAPs) and pressures (LVP, RVP) were recorded. The electromechanical window (EMW; Q to LVP at 90% relaxation minus QT interval) was calculated. LQT1 was mimicked by infusion of the KCNQ1/I Ks blocker HMR1556. Results: At baseline, LSGS and right-stellate ganglion stimulation (RSGS) caused similar heart-rate acceleration and QT shortening. Positive inotropic and lusitropic effects were more pronounced under LSGS than RSGS. I Ks blockade prolonged QTc, triggered MAP-early afterdepolarizations (EADs) and rendered the EMW negative, but no ventricular tachyarrhythmias occurred. Superimposed LSGS exaggerated EMW negativity and evoked TdP in 5/9 dogs within 30 s. Preceding extrasystoles originated mostly from the outflow-tracts region. TdP deteriorated into therapy-refractory VF in 4/5 animals. RSGS did not provoke TdP/VF. Conclusions: In this model of drug-induced LQT1, LSGS readily induced TdP and VF during repolarization prolongation and MAP-EAD generation, but only if EMW turned from positive to very negative. We postulate that altered mechano-electric coupling can exaggerate regional dispersion of refractoriness and facilitates ventricular ectopy.

Original languageEnglish
Pages (from-to)66-72
Number of pages7
JournalInternational Journal of Cardiology
Volume286
DOIs
Publication statusPublished - Jul 1 2019

Keywords

  • Autonomic nervous system
  • Long-QT syndrome
  • Torsades de pointes
  • Ventricular arrhythmia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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