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Load-induced changes in ventricular repolarization: evidence of autonomic modulation

Ksenia A Sedova1, Sergey L Goshka, Vladimir A Vityazev

  • 1a Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, 50 Pervomayskaya Street, Syktyvkar, 167982 Russia.

Canadian Journal of Physiology and Pharmacology
|November 26, 2011
PubMed

Insights

Autonomic tone significantly influences cardiac repolarization during increased hemodynamic load. Blocking autonomic signals alters ventricular repolarization patterns, impacting arrhythmogenesis risk.

Area of Science:

  • Cardiovascular Physiology
  • Autonomic Nervous System
  • Cardiac Electrophysiology

Background:

  • Increased hemodynamic load elevates arrhythmogenesis risk by altering cardiac repolarization.
  • The role of autonomic tone in modulating load-dependent repolarization changes requires further investigation.

Purpose of the Study:

  • To investigate the hypothesis that autonomic tone intervention affects load-dependent changes in ventricular repolarization.
  • To elucidate the impact of autonomic blockade on ventricular repolarization heterogeneity under augmented hemodynamic load.

Main Methods:

  • Measurement of activation-recovery intervals using 64 ventricular epicardial leads in 26 chinchilla rabbits.
  • Induction of aortic stenosis to create augmented hemodynamic load.
  • Administration of atropine and propranolol to achieve autonomic blockade prior to loading.

Main Results:

  • Short-term stenosis decreased right ventricular activation-recovery intervals; prolonged overload increased repolarization duration in both ventricles.
  • Autonomic blockade prolonged activation-recovery intervals, particularly in the left ventricle, and attenuated repolarization gradients.
  • Ventricular loading in autonomically blocked animals shortened repolarization duration, transforming biphasic changes into monophasic shortening.

Conclusions:

  • Autonomic tone is crucial for developing ventricular repolarization heterogeneity under augmented hemodynamic load.
  • Autonomic blockade significantly alters ventricular repolarization dynamics and gradients during hemodynamic stress.

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