title: Autonomic nervous system activity measured directly and QT interval variability in normal and pacing-induced tachycardia heart failure dogs.
abstract: OBJECTIVE
  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 (r(2) = 0.16; beta = -0.47; p < 0.05) whereas, during CHF, the QTVI correlated directly with integrated left stellate-ganglion nervous activity (r(2) = 0.32; beta = 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.
authors.affiliation: Dipartimento di Scienze dell'Invecchiamento, Università degli Studi di Roma La Sapienza, Rome, Italy. gianfranco.piccirillo@uniroma1.it
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Piccirillo
authors.forename: Damiano
authors.initials: D
authors.lastname: Magrì
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ogawa
authors.forename: Juan
authors.initials: J
authors.lastname: Song
authors.forename: Voon J
authors.initials: VJ
authors.lastname: Chong
authors.forename: Seongwook
authors.initials: S
authors.lastname: Han
authors.forename: Boyoung
authors.initials: B
authors.lastname: Joung
authors.forename: Eue-Keun
authors.initials: EK
authors.lastname: Choi
authors.forename: Samuel
authors.initials: S
authors.lastname: Hwang
authors.forename: Lan S
authors.initials: LS
authors.lastname: Chen
authors.forename: Shien-Fong
authors.initials: SF
authors.lastname: Lin
authors.forename: Peng-Sheng
authors.initials: PS
authors.lastname: Chen
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001341:Autonomic Nervous System / Q000502:physiology* / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial; D004195:Disease Models, Animal; D004285:Dogs; D004562:Electrocardiography; D006333:Heart Failure / Q000209:etiology*; D013564:Sympathetic Nervous System / Q000502:physiology / Q000503:physiopathology; D013610:Tachycardia / Q000150:complications* / Q000175:diagnosis; D014630:Vagus Nerve / Q000502:physiology / Q000503:physiopathology
references.citation: J Intern Med. 2006 Jan;259(1):59-69
references.pmid: 16336514
references.citation: Hypertension. 1987 Nov;10(5):538-43
references.pmid: 3666866
references.citation: Circulation. 2005 Sep 6;112(10):1392-9
references.pmid: 16129791
references.citation: Circ Res. 2003 Oct 3;93(7):638-45
references.pmid: 12933704
references.citation: Comput Biol Med. 2001 Sep;31(5):399-406
references.pmid: 11535204
references.citation: Circulation. 1996 Mar 1;93(5):1043-65
references.pmid: 8598068
references.citation: Hypertension. 1988 Dec;12(6):600-10
references.pmid: 3203964
references.citation: J Am Coll Cardiol. 2007 Jul 24;50(4):335-43
references.pmid: 17659201
references.citation: Circulation. 2003 Jun 3;107(21):2753-60
references.pmid: 12756150
references.citation: Pacing Clin Electrophysiol. 2008 Aug;31(8):1048-56
references.pmid: 18684263
references.citation: J Am Coll Cardiol. 2003 Jul 16;42(2):348-60
references.pmid: 12875775
references.citation: Circulation. 1999 Mar 16;99(10):1385-94
references.pmid: 10077525
references.citation: Am J Physiol. 1998 Aug;275(2):H369-77
references.pmid: 9683422
references.citation: Heart Rhythm. 2006 Jan;3(1):78-85
references.pmid: 16399059
references.citation: Clin Sci (Lond). 2001 Oct;101(4):429-38
references.pmid: 11566081
references.citation: Circulation. 1998 Nov 24;98(21):2334-51
references.pmid: 9826323
references.citation: Heart Rhythm. 2008 Jan;5(1):131-9
references.pmid: 18055272
references.citation: Circulation. 1980 Dec;62(6):1256-65
references.pmid: 7438361
references.citation: Circulation. 1998 Apr 14;97(14):1362-7
references.pmid: 9577947
references.citation: Circ Res. 2004 Oct 15;95(8):754-63
references.pmid: 15486322
references.citation: Eur Heart J. 2007 Jun;28(11):1344-50
references.pmid: 17101636
references.citation: J Intern Med. 2006 Jan;259(1):7-23
references.pmid: 16336510
references.citation: Am J Physiol. 1998 Nov;275(5):H1635-42
references.pmid: 9815071
references.citation: Heart Rhythm. 2007 Jul;4(7):964-72
references.pmid: 17599687
references.citation: Transl Res. 2006 Aug;148(2):72-8
references.pmid: 16890147
references.citation: Clin Sci (Lond). 2002 Mar;102(3):363-71
references.pmid: 11869178
references.citation: Am J Cardiol. 2002 Nov 15;90(10):1113-7
references.pmid: 12423713
references.citation: Circulation. 2008 Aug 26;118(9):916-25
references.pmid: 18697820
references.citation: J Toxicol Sci. 2006 Oct;31(4):381-90
references.pmid: 17077591
references.citation: Circulation. 1997 Sep 2;96(5):1557-65
references.pmid: 9315547
references.citation: Circulation. 2004 Aug 24;110(8):897-903
references.pmid: 15302799
references.citation: Am J Physiol Heart Circ Physiol. 2008 Sep;295(3):H962-H968
references.pmid: 18599596
references.citation: J Am Coll Cardiol. 2004 Oct 6;44(7):1481-7
references.pmid: 15464332
references.citation: Am J Physiol Heart Circ Physiol. 2005 Oct;289(4):H1729-35
references.pmid: 15923309
references.citation: J Am Coll Cardiol. 2000 Mar 1;35(3):778-86
references.pmid: 10716483
references.citation: Med Biol Eng Comput. 2002 Jan;40(1):79-84
references.pmid: 11954712
references.citation: Ann Noninvasive Electrocardiol. 2006 Oct;11(4):299-305
references.pmid: 17040277
references.citation: J Cardiovasc Electrophysiol. 1998 Sep;9(9):899-908
references.pmid: 9786070
references.citation: Am J Physiol Heart Circ Physiol. 2008 Sep;295(3):H923-H925
references.pmid: 18641269