title: Utility of distinctive local electrogram pattern and aortographic anatomical position in catheter manipulation at coronary cusps.
abstract: BACKGROUND
  The coronary cusps have recently become target sites for radiofrequency catheter ablation of both outflow tract ventricular arrhythmias originating near the coronary cusps (CC-VA) and atrial tachyarrhythmias such as focal atrial tachycardia originating near the noncoronary cusp (NCC-AT). However, the relation between local electrograms recorded at each CC during sinus rhythm and their anatomical position as assessed by aortography has not yet been systematically described.
  
  
  RESULTS
  In 28 patients undergoing RFCA for CC-VA or NCC-AT, amplitudes of the atrial and ventricular potentials at the CCs were measured during sinus rhythm, and the atrial/ventricular (A/V) potential ratio was computed. Relative positions of the CCs were assessed by aortography in 2 X-ray projections. In the right (RCC) and left coronary cusps (LCC), amplitudes of the ventricular potential were larger than those of the atrial potential, leading to an A/V ratio <1 in all patients (0.08 ± 0.10, 0.32 ± 0.21, respectively). In contrast, in the NCC, the amplitude of the atrial potential was larger than the ventricular potential, leading to a higher A/V ratio relative to the CCs (5.7 ± 2.6, P < 0.0001). Aortography demonstrated the rightward and anterior location of the RCC, the leftward and superior location of the LCC, and the inferior and posterior location of the NCC.
  
  
  CONCLUSIONS
  Awareness of the distinctive local electrogram pattern of each CC and their positions on aortography should lead to safer and more effective catheter ablation at the CCs.
authors.affiliation: Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan. tsasaki1@jhu.edu
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sasaki
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Hachiya
authors.forename: Kenzo
authors.initials: K
authors.lastname: Hirao
authors.forename: Koji
authors.initials: K
authors.lastname: Higuchi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hayashi
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Furukawa
authors.forename: Mihoko
authors.initials: M
authors.lastname: Kawabata
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takahashi
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Isobe
mesh_terms: D001027:Aortography / Q000379:methods*; D018780:Body Surface Potential Mapping / Q000379:methods*; D006328:Cardiac Catheterization / Q000379:methods*; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013612:Tachycardia, Ectopic Atrial / Q000175:diagnosis* / Q000601:surgery*; D016896:Treatment Outcome