title: Detection of inadvertent catheter movement into the coronary sinus ostium or middle cardiac vein by real-time impedance monitoring prior to radiofrequency ablation in the right atrial posteroseptal region.
abstract: OBJECTIVE
  The objective of this study was to evaluate the use of continuous catheter impedance monitoring prior to ablation to facilitate differentiation of the coronary sinus ostium (CSO) and the middle cardiac vein (MCV) from the right atrial posteroseptal region (RPS).
  
  
  BACKGROUND
  Empiric observations have suggested that continuous catheter impedance monitoring could differentiate the CSO and MCV from the RPS region. Radiofrequency ablation in the MCV or coronary sinus has been associated with coronary artery injury. Differentiation of these areas may be difficult with either fluoroscopy or electrogram characteristics.
  
  
  RESULTS
  Continuous impedance measurements using a 4-mm Navistar (Biosense Webster) ablation catheter were conducted in 17 consecutive patients undergoing ablation for supraventricular tachycardia. The average impedance value was recorded at the right atrial septum (RS) posterior to the bundle of His, the RPS region, within 1 cm inside the CSO and in the MCV. These areas were confirmed and demarcated with 3-D mapping and biplane fluoroscopy. A significant increase in impedance was observed between the CSO (X = 146.6 ± 24.8) and RPS [Formula: see text] regions (p < 0.001). Furthermore, a significant rise in impedance was seen between the MCV [Formula: see text] and RPS and CSO, respectively (p < 0.001). No significant change in impedance was found between the RS [Formula: see text] and RPS regions.
  
  
  CONCLUSIONS
  Continuous impedance measurements during mapping can facilitate differentiation of catheter locations inside the CSO and MCV from extracoronary sinus regions. This may reduce the risk of inadvertent coronary artery damage during the ablation procedure.
authors.affiliation: Arrhythmia and Ablation Center, Department of Cardiology, Florida Hospital, Orlando, FL, USA.
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Pollak
authors.forename: Heather
authors.initials: H
authors.lastname: Seckel
authors.forename: Joseph
authors.initials: J
authors.lastname: Monir
authors.forename: George
authors.initials: G
authors.lastname: Ebra
authors.forename: George
authors.initials: G
authors.lastname: Monir
mesh_terms: D000328:Adult; D000368:Aged; D006328:Cardiac Catheterization; D017115:Catheter Ablation / Q000009:adverse effects* / Q000295:instrumentation*; D054326:Coronary Sinus / Q000293:injuries*; D003331:Coronary Vessels / Q000293:injuries*; D017097:Electric Impedance; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005548:Foreign-Body Migration / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome