title: Heart rate variability measurement and clinical depression in acute coronary syndrome patients: narrative review of recent literature.
abstract: OBJECTIVE
  We aimed to explore links between heart rate variability (HRV) and clinical depression in patients with acute coronary syndrome (ACS), through a review of recent clinical research literature.
  
  
  BACKGROUND
  Patients with ACS are at risk for both cardiac autonomic dysfunction and clinical depression. Both conditions can negatively impact the ability to recover from an acute physiological insult, such as unstable angina or myocardial infarction, increasing the risk for adverse cardiovascular outcomes. HRV is recognized as a reflection of autonomic function.
  
  
  METHODS
  A narrative review was undertaken to evaluate state-of-the-art clinical research, using the PubMed database, January 2013. The search terms "heart rate variability" and "depression" were used in conjunction with "acute coronary syndrome", "unstable angina", or "myocardial infarction" to find clinical studies published within the past 10 years related to HRV and clinical depression, in patients with an ACS episode. Studies were included if HRV measurement and depression screening were undertaken during an ACS hospitalization or within 2 months of hospital discharge.
  
  
  RESULTS
  Nine clinical studies met the inclusion criteria. The studies' results indicate that there may be a relationship between abnormal HRV and clinical depression when assessed early after an ACS event, offering the possibility that these risk factors play a modest role in patient outcomes.
  
  
  CONCLUSIONS
  While a definitive conclusion about the relevance of HRV and clinical depression measurement in ACS patients would be premature, the literature suggests that these measures may provide additional information in risk assessment. Potential avenues for further research are proposed.
authors: ECG Monitoring Research Lab, University of California, San Francisco, CA, USA.
authors: Patricia Re
authors: PR
authors: Harris
authors: Department of Physiological Nursing, School of Nursing, University of California, San Francisco, CA, USA.
authors: Claire E
authors: CE
authors: Sommargren
authors: Heart Rate Variability Laboratory, School of Medicine, Washington University, St Louis, MO, USA.
authors: Phyllis K
authors: PK
authors: Stein
authors: Asian Heart & Vascular Center at Mount Zion, Division of Cardiology, University of California, San Francisco, CA, USA ; Cardiology Consultation Service, Cardiac Noninvasive Laboratory, and The Enhanced External Counterpulsation Unit, Department of Medicine, University of California, San Francisco Medical Center, San Francisco, CA, USA.
authors: Gordon L
authors: GL
authors: Fung
authors: Division of Cardiology, University of California, San Francisco, CA, USA ; Department of Physiological Nursing, School of Nursing, University of California, San Francisco, CA, USA.
authors: Barbara J
authors: BJ
authors: Drew
keywords: autonomic nervous system; depressive disorder; outcomes research; risk assessment