title: Combined ventricular endocardial and epicardial substrate mapping using a sonomicrometry-based electroanatomical mapping system.
abstract: BACKGROUND
  Substrate mapping using a magnetic electroanatomical mapping system (MEAM) has been shown to accurately delineate the location/extent of scarred myocardium. This study examined the ability of a sonomicrometry-based electroanatomic mapping system (SEAM) to render endocardial and epicardial substrate maps of infarcted ventricular myocardium.
  
  
  RESULTS
  In 7 swine with healed myocardial infarctions, combined epicardial and endocardial left ventricular (LV) substrate maps were created with both SEAM and MEAM mapping systems using 246+/-68 and 244+/-44 points respectively. Scarred myocardium was identified based upon bipolar electrogram amplitude < 1.5 mV, and radiofrequency ablation lesions were delivered to the scar border as defined by the sonomicrometry mapping system. The LV endocardial chamber volume as defined by SEAM (125+/-46 ml) correlated well with that defined by the MEAM (137+/-45 ml, r=0.77, p < 0.05). The area of infarcted tissue as determined by SEAM was highly correlated with that determined by gross pathology (r=0.96 for endocardial scar and r=0.92 for epicardial scar p < 0.05). The scar area calculated by the SEAM system also correlated well with the scar area determined by the MEAM system (0.91 for endocardial scar and 0.90 for epicardial scar p < 0.05). Finally, the sonomicrometry-based system was able to guide the placement of radiofrequency ablation lesions to the borders of the scar.
  
  
  CONCLUSIONS
  This study demonstrates that the sonomicrometry-based mapping can accurately reconstruct three-dimensional voltage maps of the endocardial and epicardial ventricular surfaces and guide the placement of ablation lesions along the scar border zone.
authors.affiliation: Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, Massachusetts 02114, USA. adavila@partners.org
authors.forename: Andre
authors.initials: A
authors.lastname: D'Avila
authors.forename: Aravinda
authors.initials: A
authors.lastname: Thiagalingam
authors.forename: Jeremy N
authors.initials: JN
authors.lastname: Ruskin
authors.forename: Vivek Y
authors.initials: VY
authors.lastname: Reddy
mesh_terms: D000818:Animals; D004699:Endocardium / Q000473:pathology*; D006352:Heart Ventricles / Q000473:pathology*; D009203:Myocardial Infarction / Q000473:pathology*; D010496:Pericardium / Q000473:pathology*; D013552:Swine