title: Sinus node function after cardiac surgery: is impairment specific for the maze procedure?
abstract: BACKGROUND
  Maze surgery is a final solution for intractable atrial fibrillation (AF), but an adverse effect on postoperative sinus node function has been reported. Whether this also applies to other types of cardiac surgery is unclear.
  
  
  METHODS
  We assessed postoperative rhythm by means of repeated exercise tolerance testing, ambulatory electrocardiography, and non-invasive testing of autonomic function between 1 and 12 months after four types of cardiac surgery. Fourteen patients without structural cardiac disease and medically refractory AF underwent the maze III procedure, 11 patients with mitral valve disease and preoperative AF underwent valvar surgery combined with a (simplified) maze III procedure, and 8 patients with mitral valve disease in sinus rhythm (SR) underwent isolated valvar surgery. The control group consisted of eight patients with sinus rhythm who underwent coronary artery bypass surgery (CABG).
  
  
  RESULTS
  One month after surgery, the chronotropic response to exercise was depressed, mean heart rate was high, and heart rate variability (HRV) was low, especially after maze III, combined surgery, and isolated valvar surgery. Twelve months after surgery, moderate improvements were observed. After CABG, considerably fewer abnormalities were observed, and HRV parameters recovered to a large extent. Non-invasive testing of autonomic function indicated disturbed vagal modulation of heart rate in all three groups with atrial incision.
  
  
  CONCLUSIONS
  Thus, attenuation of HRV and vagal modulation of sinus node function are not confined to maze surgery but also apply to isolated mitral valve surgery. Atrial incision therefore appears to be crucial and presumably produces autonomic nervous damage followed by partial reinnervation. Nevertheless, cardiac surgery in general seems initially to impair sinus node function with partial recovery in the consecutive 12 months.
authors.affiliation: Department of Cardiology, Thoraxcenter, University Hospital Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands. a.e.tuinenburg@thorax.azg.nl
authors.forename: Anton E
authors.initials: AE
authors.lastname: Tuinenburg
authors.forename: Isabelle C
authors.initials: IC
authors.lastname: Van Gelder
authors.forename: Maarten P
authors.initials: MP
authors.lastname: Van Den Berg
authors.forename: Jan G
authors.initials: JG
authors.lastname: Grandjean
authors.forename: Robert G
authors.initials: RG
authors.lastname: Tieleman
authors.forename: Andries J
authors.initials: AJ
authors.lastname: Smit
authors.forename: Rolf C G
authors.initials: RC
authors.lastname: Huet
authors.forename: Joost M A A
authors.initials: JM
authors.lastname: Van Der Maaten
authors.forename: Corine P
authors.initials: CP
authors.lastname: Volkers
authors.forename: Tjark
authors.initials: T
authors.lastname: Ebels
authors.forename: Harry J G M
authors.initials: HJ
authors.lastname: Crijns
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000601:surgery; D016275:Atrial Function / Q000502:physiology*; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D015716:Electrocardiography, Ambulatory; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000503:physiopathology / Q000601:surgery; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology / Q000503:physiopathology; D011446:Prospective Studies; D012849:Sinoatrial Node / Q000502:physiology*; D013997:Time Factors; D016896:Treatment Outcome