Autonomic Nervous System Activity Measured Directly and QT Interval Variability in Normal and Pacing-Induced Tachycardia Heart Failure Dogs

Gianfranco Piccirillo, Damiano Magrì, Masahiro Ogawa, Juan Song, Voon J. Chong, Seongwook Han, Boyoung Joung, Eue Keun Choi, Samuel Hwang, Lan S. Chen, Shien Fong Lin, Peng Sheng Chen

Research output: Contribution to journalArticle

84 Scopus citations


Objectives: This study sought to find out more about the relationship between sympathetic and vagal nerve activity and the cardiac repolarization in a canine model of pacing-induced tachycardia congestive heart failure (CHF). Background: The QT variability index (QTVI), a noninvasive marker of temporal cardiac repolarization dispersion, is among the risk factors for sudden death during CHF. Among factors influencing this variable are the myocardial damage and the autonomic nervous system activity typical of dilated cardiomyopathy. Methods: We assessed autonomic nervous system activity recorded from an implanted data transmitter that monitored integrated left stellate-ganglion nervous activity, integrated vagus nerve activity, and electrocardiogram. We collected 36 segments recorded at baseline and 36 after induced CHF. We then arbitrarily identified recording segments as containing low or high sympathetic activity values, and we compared corrected QT intervals and the QTVI under a given sympathetic activity condition at baseline and after inducing CHF. Results: In the high sympathetic activity subgroup, both QT variables increased from baseline to CHF (corrected QT intervals, p < 0.01; QTVI, p < 0.05) whereas in the low sympathetic activity subgroup they remained unchanged. The baseline QTVI correlated inversely with integrated vagus nerve activity (r2 = 0.16; β = -0.47; p < 0.05) whereas, during CHF, the QTVI correlated directly with integrated left stellate-ganglion nervous activity (r2 = 0.32; β = 0.27, p < 0.01). Conclusions: During CHF, sympathetic activation is associated with an increase in the QT interval and QTVI. Because these changes vary over time, they could result from myocardial structural damage and sympathetic activation combined. Conversely, under normal conditions, no relationship exists between sympathetic activation and the QT variables.

Original languageEnglish (US)
Pages (from-to)840-850
Number of pages11
JournalJournal of the American College of Cardiology
Issue number9
StatePublished - Aug 25 2009



  • autonomic nervous system
  • congestive heart failure
  • QT variability index
  • sudden cardiac death

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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