title: Effects of Spinal Cord Stimulation on Cardiac Sympathetic Nerve Activity in Patients with Heart Failure.
abstract: BACKGROUND
  Spinal cord stimulation (SCS) reduces sympathetic activity in animal models of heart failure with reduced ejection fraction (HF) but limited data exist of SCS in patients with HF. The aim of the present study was to test the primary hypothesis that SCS reduces cardiac sympathetic nerve activity in HF patients. Secondary hypotheses were that SCS improves left ventricular function and dimension, exercise capacity, and clinical variables relevant to HF.
  
  
  METHODS
  HF patients with a SCS device previously participating in the DEFEAT-HF trial were included in this crossover study with 6-week intervention periods (SCS-ON and SCS-OFF). SCS (50 Hz, 210-μs pulse duration, aiming at T2-T4 segments) was delivered for 12 hours daily. Indices of myocardial sympathetic neuronal function (heart-to-mediastinum ratio, HMR) and activity (washout rate, WR) were assessed using123I-metaiodobenzylguanidine (MIBG) scintigraphy. Echocardiography, exercise testing, and clinical data collection were also performed.
  
  
  RESULTS
  We included 13 patients (65.3 ± 8.0 years, nine males) and MIBG scintigraphy data were available in 10. HMR was not different comparing SCS-ON (1.37 ± 0.16) and SCS-OFF (1.41 ± 0.21, P = 0.46). WR was also unchanged comparing SCS-ON (41.5 ± 5.3) and SCS-OFF (39.1 ± 5.8, P = 0.30). Similarly, average New York Heart Association class (2.4 ± 0.5 vs 2.3 ± 0.6, P = 0.34), quality of life score (24 ± 16 vs 24 ± 16, P = 0.94), and left ventricular dimension and function as well as exercise capacity were all unchanged comparing SCS-ON and SCS-OFF.
  
  
  CONCLUSIONS
  In patients with HF, SCS (12 hours daily, targeting the T2-T4 segments of the spinal cord) does not appear to influence cardiac sympathetic neuronal activity or function as assessed by MIBG scintigraphy.
authors.affiliation: Department of Cardiology, Na Homolce Hospital, Prague, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Naar
authors.affiliation: Cardiac Rhythm and Heart Failure, Medtronic Plc, Minneapolis, Minnesota.
authors.forename: Deborah
authors.initials: D
authors.lastname: Jaye
authors.affiliation: Department of Medicine, Solna, Karolinska Institutet, and Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Linde
authors.affiliation: Department of Cardiology, Na Homolce Hospital, Prague, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Neužil
authors.affiliation: Department of Cardiology, Na Homolce Hospital, Prague, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Doškář
authors.affiliation: Department of Cardiology, Na Homolce Hospital, Prague, Czech Republic.
authors.forename: Filip
authors.initials: F
authors.lastname: Málek
authors.affiliation: Department of Medicine, Solna, Karolinska Institutet, and Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Frieder
authors.initials: F
authors.lastname: Braunschweig
authors.affiliation: Department of Medicine, Solna, Karolinska Institutet, and Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Lars H
authors.initials: LH
authors.lastname: Lund
authors.affiliation: Department of Medicine, Solna, Karolinska Institutet, and Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Mortensen
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, and Department of Neurosurgery, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Bengt
authors.initials: B
authors.lastname: Linderoth
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, and Department of Neurosurgery, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Göran
authors.initials: G
authors.lastname: Lind
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, and Department of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Dianna
authors.initials: D
authors.lastname: Bone
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Scholte
authors.affiliation: Cardiac Rhythm and Heart Failure, Medtronic Plc, Minneapolis, Minnesota.
authors.forename: Fred
authors.initials: F
authors.lastname: Kueffer
authors.affiliation: Cardiac Rhythm and Heart Failure, Medtronic Plc, Minneapolis, Minnesota.
authors.forename: Jodi
authors.initials: J
authors.lastname: Koehler
authors.affiliation: Department of Clinical Physiology, Sunderby Hospital, Luleå, Sweden.
authors.forename: Kambiz
authors.initials: K
authors.lastname: Shahgaldi
authors.affiliation: Department of Nuclear Medicine, University Hospital Královské Vinohrady, Prague, Czech Republic.
authors.forename: Otto
authors.initials: O
authors.lastname: Lang
authors.affiliation: Department of Medicine, Solna, Karolinska Institutet, and Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Marcus
authors.initials: M
authors.lastname: Ståhlberg
mesh_terms: D000368:Aged; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging / Q000294:innervation* / Q000503:physiopathology*; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy*; D006801:Humans; D008297:Male; D013116:Spinal Cord / Q000000981:diagnostic imaging / Q000503:physiopathology*; D062187:Spinal Cord Stimulation / Q000379:methods*; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D016896:Treatment Outcome
keywords: heart failure; imaging; spinal cord stimulation; sympathetic nervous system