title: Pulmonary vein isolation and the Cox maze procedure only partially denervate the atrium.
abstract: OBJECTIVE
  The effects of ablation lines on myocardial innervation and response to autonomic stimuli are unclear. This study examined the effects of radiofrequency ablation on atrial autonomic innervation and compared pulmonary vein isolation and the biatrial Cox maze procedure.
  
  
  METHODS
  In 12 acute canines right and left vagosympathetic trunks and right and left stellate ganglia were isolated. Each nerve was stimulated before bipolar ablation, after pulmonary vein isolation, and after the Cox maze procedure. Nadolol (n = 6) and atropine (n = 6) were administered to block sympathetic and parasympathetic responses, respectively. Changes in heart rate and atrioventricular interval were compared. Changes in QRST area relative to an isoelectric baseline (index of local innervation) were calculated.
  
  
  RESULTS
  Sympathetic stimulation of each nerve and parasympathetic stimulation of the vagosympathetic trunks caused significant changes in heart rate and atrioventricular interval. After pulmonary vein isolation, the effect of 33% of the nerves on heart rate changes was eliminated. The Cox maze procedure eliminated right stellate sympathetic effects on heart rate. Fifty percent of the nerves caused heart rate changes after the Cox maze procedure. There was no significant effect of either lesion set on atrioventricular interval changes. Stimulation of 50% of nerves after pulmonary vein isolation produced local area changes significantly different from control area. After the Cox maze procedure, a different 50% of the nerves produced local changes different from those seen after pulmonary vein isolation.
  
  
  CONCLUSIONS
  Surgical ablation procedures disrupted innervation, affecting heart rate but not atrioventricular interval. Autonomic innervation affecting the atria was changed by pulmonary vein isolation and additionally by the Cox maze procedure. Residual autonomic effects were present even after the complete Cox maze procedure.
authors: Division of Cardiothoracic Surgery, Washington University School of Medicine, Saint Louis, MO 63110, USA.
authors: Shelly C
authors: SC
authors: Lall
authors: Kelley V
authors: KV
authors: Foyil
authors: Shun-ichiro
authors: S
authors: Sakamoto
authors: Rochus K
authors: RK
authors: Voeller
authors: John P
authors: JP
authors: Boineau
authors: Ralph J
authors: RJ
authors: Damiano
authors: Richard B
authors: RB
authors: Schuessler
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000601:surgery*; D006348:Cardiac Surgical Procedures / Q000379:methods*; D017115:Catheter Ablation; D004285:Dogs; D006325:Heart Atria / Q000294:innervation* / Q000601:surgery; D023421:Models, Animal; D011667:Pulmonary Veins / Q000601:surgery*