title: Utility of transesophageal electrocardiography to guide optimal placement of a transesophageal pacing catheter in dogs.
abstract: OBJECTIVE
  To determine if the transesophageal atrial (A) wave amplitude or ventricular (V) wave amplitude can be used to guide optimal positioning of a transesophageal pacing catheter in dogs.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  Fourteen client owned healthy dogs with a median weight of 15.4 kg (IQR = 10.6-22.4) and a median age of 12 months (IQR = 6-12).
  
  
  METHODS
  Transesophageal atrial pacing (TAP) using a 6 Fr pacing catheter was attempted in dogs under general anesthesia. The pacing catheter was inserted orally into the esophagus to a position caudal to the heart. With the pulse generator set at a rate 20 beats/minute(-1) above the intrinsic sinus rate, the catheter was slowly withdrawn until atrial pacing was noted on a surface electrocardiogram (ECG). Then the catheter was withdrawn in 1 cm increments until atrial capture was lost. Minimum pacing threshold (MPT) and transesophageal ECG were recorded at each site. Amplitudes of the A and V waves on transesophageal ECG were then measured and their relationship to MPT was evaluated.
  
  
  RESULTS
  TAP was achieved in all dogs. In 9/14 dogs the site of lowest overall MPT was the same as the site of maximal A wave deflection. In dogs with at least three data points, linear regression analysis of the relationship between the estimated site of the lowest overall MPT compared to estimated site of the maximal A and V waveform amplitudes demonstrated a strong correlation (R(2) = 0.99).
  
  
  CONCLUSIONS
  Transesophageal ECG A and V waveforms were correlated to MPT and could be used to direct the placement of a pacing catheter. However, the technique was technically challenging and was not considered to be clinically useful to guide the placement of a pacing catheter.
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Sanders
authors.forename: Emily
authors.initials: E
authors.lastname: Chapel
authors.forename: Fernando L
authors.initials: FL
authors.lastname: Garcia-Pereira
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Venet
mesh_terms: D000818:Animals; D002304:Cardiac Pacing, Artificial / Q000379:methods / Q000662:veterinary; D057785:Catheters / Q000662:veterinary*; D004285:Dogs; D004562:Electrocardiography / Q000379:methods / Q000662:veterinary*; D004947:Esophagus; D010138:Pacemaker, Artificial / Q000662:veterinary
keywords: atrial; bradycardia; pacing; transesophageal