title: Entrainment mapping for rapid distinction of left and right atrial tachycardias.
abstract: BACKGROUND
  Distinguishing left from right atrial tachycardia is a critical step for guiding ablation.
  
  
  OBJECTIVE
  The purpose of this study was to develop and validate a simple algorithm predicting the location of macroreentrant atrial tachycardia (AT) circuits from limited entrainment mapping in right atrium (RA) and coronary sinus (CS).
  
  
  METHODS
  In 180 patients with organized reentrant AT, entrainment was performed at the high RA, proximal CS, and distal CS. The difference between the postpacing interval (PPI) and tachycardia cycle length (TCL) was calculated at each site. The location of the AT reentrant circuit was determined by mapping and ablation. An algorithm predicting AT regions was developed from 104 ATs in the first 90 patients (group I) and prospectively evaluated in a validation cohort of 106 ATs in the second 90 patients (group II).
  
  
  RESULTS
  In group I, PPI-TCL difference <50 or >50 ms at the high RA distinguished RA from LA reentrant circuits. For RA tachycardias, PPI-TCL difference at the proximal CS distinguished common flutter from lateral RA circuits. For LA circuits, PPI-TCL difference at the proximal and distal CS distinguished perimitral reentry from reentry involving the right pulmonary veins and septum. In group II, an algorithm based on PPI-TCL difference >50 or <50 ms at the high RA, proximal CS, or distal CS had sensitivity of 94%, specificity of 88%, and predictive accuracy of 93% for predicting the successful ablation region.
  
  
  CONCLUSIONS
  Limited entrainment from sites accessible from the RA can expeditiously suggest the AT location to guide more detailed mapping and potentially avoid unnecessary transseptal punctures in some patients.
authors.affiliation: Cardiovascular Division, Department of Internal Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Miyazaki
authors.forename: William G
authors.initials: WG
authors.lastname: Stevenson
authors.forename: Kent
authors.initials: K
authors.lastname: Stephenson
authors.forename: Kyoko
authors.initials: K
authors.lastname: Soejima
authors.forename: Laurence M
authors.initials: LM
authors.lastname: Epstein
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001282:Atrial Flutter / Q000503:physiopathology / Q000601:surgery; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006325:Heart Atria / Q000473:pathology / Q000601:surgery; D006329:Heart Conduction System / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012107:Research Design; D013612:Tachycardia, Ectopic Atrial / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D016896:Treatment Outcome