title: Depression and reduced heart rate variability after cardiac surgery: the mediating role of emotion regulation.
abstract: BACKGROUND
  Heart rate variability (HRV), as an index of autonomic nervous system (ANS) functioning, is reduced by depression after cardiac surgery, but the underlying mechanisms of this relationship are poorly understood. Poor emotion regulation as a core symptom of depression has also been associated with altered ANS functioning. The present study aimed to examine whether emotion dysregulation could be a mediator of the depression-reduced HRV relationship observed after cardiac surgery.
  
  
  METHODS
  Self-reported emotion regulation and four-minute HRV were measured in 25 depressed and 43 nondepressed patients after cardiac surgery. Mediation analysis was conducted to evaluate emotion regulation as a mediator of the depression-reduced HRV relationship.
  
  
  RESULTS
  Compared to nondepressed patients, those with depression showed lower standard deviation of normal-to-normal (NN) intervals (p<.05), root mean square successive difference of NN intervals (p<.004), and number of interval differences of successive NN intervals greater than 50ms (NN50) (p<.05). Increased low frequency (LF) in normalized units (n.u.) and reduced high frequency (HF) n.u. were also found in depressed compared to nondepressed patients (p's<.01). Mediation analysis revealed that suppression of emotion-expressive behavior partially mediated the effect of depression on LF n.u. and HF n.u.
  
  
  CONCLUSIONS
  Results confirmed previous findings showing that depression is associated with reduced HRV, especially a reduced vagal tone and a sympathovagal imbalance, after cardiac surgery. This study also provides preliminary evidence that increased trait levels of suppression of emotion-expressive behavior may mediate the depression-related sympathovagal imbalance after cardiac surgery.
authors.affiliation: Department of General Psychology, University of Padua, Italy. Electronic address: elisabetta.patron@studenti.unipd.it.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Patron
authors.affiliation: Department of General Psychology, University of Padua, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Messerotti Benvenuti
authors.affiliation: Department of Preventive and Rehabilitative Cardiology, Motta di Livenza Hospital, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Favretto
authors.affiliation: Department of Preventive and Rehabilitative Cardiology, Motta di Livenza Hospital, Italy.
authors.forename: Renata
authors.initials: R
authors.lastname: Gasparotto
authors.affiliation: Department of General Psychology, University of Padua, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Palomba
mesh_terms: D000223:Adaptation, Psychological; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D001341:Autonomic Nervous System / Q000503:physiopathology*; D002317:Cardiovascular Agents / Q000627:therapeutic use; D001026:Coronary Artery Bypass / Q000523:psychology; D003863:Depression / Q000209:etiology / Q000503:physiopathology*; D004644:Emotions / Q000502:physiology*; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology*; D019918:Heart Valve Prosthesis Implantation / Q000523:psychology; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology / Q000503:physiopathology*; D011795:Surveys and Questionnaires; D014630:Vagus Nerve / Q000503:physiopathology
chemical_list: D000925:Anticoagulants; D002317:Cardiovascular Agents
keywords: Cardiac surgery; Cognitive reappraisal; Depression; Emotion regulation; Emotion suppression; Heart rate variability