title: Heart rate turbulence parameters correlate with post-premature ventricular contraction changes in muscle sympathetic activity.
abstract: BACKGROUND
  Heart rate turbulence (HRT) has been shown to be vagally mediated with a strong correlation to baroreflex indices. However, the relationship between HRT and peripheral sympathetic nerve activity (SNA) after a premature ventricular contraction (PVC) remains unclear.
  
  
  OBJECTIVE
  We sought to evaluate the relationship between HRT and the changes in peripheral SNA after PVCs.
  
  
  METHODS
  We recorded postganglionic muscle SNA during electrocardiogram monitoring in eight patients with spontaneous PVCs. Fifty-two PVCs were observed and analyzed for turbulence onset (TO) and slope (TS). SNA was quantified during (1) the dominant burst after the PVC (dominant burst area) and (2) the 10 seconds after the dominant burst (postburst SNA).
  
  
  RESULTS
  The mean TO was 0.1% +/- 4.6%, and the mean TS was 6.1 +/- 6.6. The dominant burst area negatively correlated with TO (r = -0.50, P = .0002). The postburst SNA showed a significant positive correlation with TO (r = 0.44, P = .001) and a negative correlation with TS (r = -0.42, P = .002). These correlations remained significant after controlling for either the PVC coupling interval or the left ventricular ejection fraction.
  
  
  CONCLUSIONS
  Our findings highlight the relationship between perturbations in HRT and pathology in the sympathetic limb of the autonomic nervous system. Future studies are needed to evaluate the prognostic role of baroreflex control of sympathetic activity in patients with structural heart disease.
authors.affiliation: Department of Internal Medicine, Division of Cardiology, University of Utah, Salt Lake City, Utah 84132, USA. Nathan.Segerson@hsc.utah.edu
authors.forename: Nathan M
authors.initials: NM
authors.lastname: Segerson
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Wasmund
authors.forename: Moeen
authors.initials: M
authors.lastname: Abedin
authors.forename: Rakesh K
authors.initials: RK
authors.lastname: Pai
authors.forename: Marcos
authors.initials: M
authors.lastname: Daccarett
authors.forename: Nazem
authors.initials: N
authors.lastname: Akoum
authors.forename: T Scott
authors.initials: TS
authors.lastname: Wall
authors.forename: Richard C
authors.initials: RC
authors.lastname: Klein
authors.forename: Roger A
authors.initials: RA
authors.lastname: Freedman
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Hamdan
mesh_terms: D000704:Analysis of Variance; D001794:Blood Pressure; D004562:Electrocardiography; D005121:Extremities / Q000294:innervation; D005260:Female; D006339:Heart Rate; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation*; D012107:Research Design; D013318:Stroke Volume; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D018879:Ventricular Premature Complexes / Q000503:physiopathology*