title: Direct evidences for sympathetic hyperactivity and baroreflex impairment in Tako Tsubo cardiopathy.
abstract: BACKGROUND
  The exact pathophysiology of Tako-Tsubo cardiomyopathy (TTC) remains unknown but a role for sympathetic hyperactivity has been suggested. Up to now, no direct evidence of sympathetic nerve hyperactivity has been established nor involvement of sympathetic baroreflex identified. The aim of our study was to determine, by direct sympathetic nerve activity (SNS) recording if sympathetic nervous system activity is increased and spontaneous baroreflex control of sympathetic activity reduced in patients with TTC.
  
  
  METHODS
  We included 13 patients who presented with TTC and compared their SNS activity and spontaneous baroreflex control of sympathetic activity with that of 13 control patients with acutely decompensated chronic heart failure. SNS activity was evaluated by microneurography, a technique assessing muscle sympathetic nerve activity (MSNA). Spontaneous baroreflex control of sympathetic activity was evaluated as the absolute value of the slope of the regression line representing the relationship between spontaneous diastolic blood pressure values and concomitant SNS activity. Control patients were matched for age, sex, left ventricular ejection fraction and creatinine clearance.
  
  
  RESULTS
  The mean age of the patients with TTC was 80 years, all patients were women. There were no significant differences between the two groups of patients for blood pressure, heart rate or oxygen saturation level. TTC patients presented a significant increase in sympathetic nerve activity (MSNA median 63.3 bursts/min [interquartile range 61.3 to 66.0] vs median 55.7 bursts/min [interquartile range 51.0 to 61.7]; p = 0.0089) and a decrease in spontaneous baroreflex control of sympathetic activity compared to matched control patients (spontaneous baroreflex control of sympathetic activity median 0.7%burst/mmHg [interquartile range 0.4 to 1.9] vs median 2.4%burst/mmHg [interquartile range 1.8 to 2.9]; p = 0.005).
  
  
  CONCLUSIONS
  We report for the first time, through direct measurement of sympathetic nerve activity, that patients with TTC exhibit elevated SNS activity associated with a decrease in spontaneous baroreflex control of sympathetic activity. These data may explain the pathophysiology and clinical presentation of patient with TTC.
authors.affiliation: National Institute of Health and Medical Research (INSERM) UMR-1048, Institute of Metabolic and Cardiovascular diseases, Toulouse, France; C.I.C., Clinical Investigation Center, University Hospital of Toulouse, Toulouse, France.
authors.forename: Angelica
authors.initials: A
authors.lastname: Vaccaro
authors.affiliation: National Institute of Health and Medical Research (INSERM) UMR-1048, Institute of Metabolic and Cardiovascular diseases, Toulouse, France; Toulouse University III Paul Sabatier, Toulouse, France; Clinical Pharmacology Department, University Hospital of Toulouse, Toulouse, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Despas
authors.affiliation: National Institute of Health and Medical Research (INSERM) UMR-1048, Institute of Metabolic and Cardiovascular diseases, Toulouse, France; Department of Cardiology, University Hospital of Toulouse, Toulouse, France.
authors.forename: Clement
authors.initials: C
authors.lastname: Delmas
authors.affiliation: National Institute of Health and Medical Research (INSERM) UMR-1048, Institute of Metabolic and Cardiovascular diseases, Toulouse, France; Toulouse University III Paul Sabatier, Toulouse, France; Department of Cardiology, University Hospital of Toulouse, Toulouse, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Lairez
authors.affiliation: Human Neurotransmitter Laboratory, Baker IDI Heart and Diabetes Institute and Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Lambert
authors.affiliation: Human Neurotransmitter Laboratory, Baker IDI Heart and Diabetes Institute and Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Gavin
authors.initials: G
authors.lastname: Lambert
authors.affiliation: National Institute of Health and Medical Research (INSERM) UMR-1048, Institute of Metabolic and Cardiovascular diseases, Toulouse, France; Toulouse University III Paul Sabatier, Toulouse, France; Department of Cardiology, University Hospital of Toulouse, Toulouse, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Labrunee
authors.affiliation: National Institute of Health and Medical Research (INSERM) UMR-1048, Institute of Metabolic and Cardiovascular diseases, Toulouse, France; Toulouse University III Paul Sabatier, Toulouse, France.
authors.forename: Thibaut
authors.initials: T
authors.lastname: Guiraud
authors.affiliation: Human Neurotransmitter Laboratory, Baker IDI Heart and Diabetes Institute and Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Murray
authors.initials: M
authors.lastname: Esler
authors.affiliation: National Institute of Health and Medical Research (INSERM) UMR-1048, Institute of Metabolic and Cardiovascular diseases, Toulouse, France; Toulouse University III Paul Sabatier, Toulouse, France; Department of Cardiology, University Hospital of Toulouse, Toulouse, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Galinier
authors.affiliation: National Institute of Health and Medical Research (INSERM) UMR-1048, Institute of Metabolic and Cardiovascular diseases, Toulouse, France; Toulouse University III Paul Sabatier, Toulouse, France; Clinical Pharmacology Department, University Hospital of Toulouse, Toulouse, France; Department of Cardiology, University Hospital of Toulouse, Toulouse, France.
authors.forename: Jean Michel
authors.initials: JM
authors.lastname: Senard
authors.affiliation: National Institute of Health and Medical Research (INSERM) UMR-1048, Institute of Metabolic and Cardiovascular diseases, Toulouse, France; Toulouse University III Paul Sabatier, Toulouse, France; Clinical Pharmacology Department, University Hospital of Toulouse, Toulouse, France; Department of Cardiology, University Hospital of Toulouse, Toulouse, France; Human Neurotransmitter Laboratory, Baker IDI Heart and Diabetes Institute and Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia; C.I.C., Clinical Investigation Center, University Hospital of Toulouse, Toulouse, France.
authors.forename: Atul
authors.initials: A
authors.lastname: Pathak
mesh_terms: D000369:Aged, 80 and over; D017704:Baroreflex; D001794:Blood Pressure / Q000502:physiology; D016022:Case-Control Studies; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000294:innervation; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D054549:Takotsubo Cardiomyopathy / Q000503:physiopathology*