title: Normal atrial activation and voltage during sinus rhythm in the human heart: an endocardial and epicardial mapping study in patients with a history of atrial fibrillation.
abstract: BACKGROUND
  The three-dimensional contributions to human atrial activation in sinus rhythm have not been specifically characterized. We evaluated the sequence of endocardial and epicardial activation and voltage of the atria during normal sinus rhythm.
  
  
  RESULTS
  The study group includes 35 patients with history of symptomatic atrial fibrillation. Prior to catheter ablation of atrial fibrillation, we performed multielectrode electroanatomic mapping during sinus rhythm, endocardially of the RA, LA, and coronary sinus (CS) and, in 10 patients, epicardially of the transverse sinus and oblique sinus. Following activation of the atrial region of the sinus node, the epicardial transverse sinus was activated 11 +/- 18 msec later, while the earliest endocardial LA activation occurred in the region of Bachmann's bundle at 31 +/- 13 msec, significantly earlier than the earliest epicardial LA activation of the oblique sinus at 54 +/- 10 msec (P < 0.002). The posterior LA revealed complex types of activation in 66% of patients analyzed, due to the convergence of wavefront propagation from the CS, oblique sinus, and endocardial LA. Bipolar voltage measurements revealed significantly higher values for the epicardium (mean 3.05 +/- 1.31 mv) than for the endocardium (mean 1.65 +/- 0.75 mv), P < 0.0001 between both groups.
  
  
  CONCLUSIONS
  In sinus rhythm, we have characterized endocardial and epicardial atrial activation and voltage, and provide an analysis and understanding of the genesis of the P wave complex in humans.
authors: Division of Cardiology, University of Ottawa Heart Institute, Ottawa, ON, Canada. RLemery@ottawaheart.ca
authors: Robert
authors: R
authors: Lemery
authors: David
authors: D
authors: Birnie
authors: Anthony S L
authors: AS
authors: Tang
authors: Martin
authors: M
authors: Green
authors: Michael
authors: M
authors: Gollob
authors: Matt
authors: M
authors: Hendry
authors: Ernest
authors: E
authors: Lau
mesh_terms: D001281:Atrial Fibrillation / Q000503:physiopathology*; D016275:Atrial Function; D018780:Body Surface Potential Mapping / Q000379:methods; D004699:Endocardium / Q000502:physiology / Q000503:physiopathology; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010496:Pericardium / Q000502:physiology / Q000503:physiopathology; D012849:Sinoatrial Node / Q000502:physiology / Q000503:physiopathology*