title: Idiopathic ventricular arrhythmias originating from the left ventricular summit: anatomic concepts relevant to ablation.
abstract: BACKGROUND
  The summit of the left ventricle (LV) is the most superior portion of the epicardial LV bounded by an arc from the left anterior descending coronary artery, superior to the first septal perforating branch to the left circumflex coronary artery. Ventricular arrhythmias (VAs) originating from this region may present challenges for catheter ablation.
  
  
  RESULTS
  We studied 27 consecutive patients with VAs originating from the LV summit. The great cardiac vein (GCV) divides this region between an inferior area accessible to ablation and a superior, inaccessible area. Successful ablation was achieved within the GCV in 14 patients and on the epicardial surface in 4. Ventricular prepotentials were recorded at the successful ablation site in 80% of these patients. In 5 patients, ablation was abandoned because of inaccessibility of the catheter to the myocardium or high impedance with radiofrequency application within the GCV. In the remaining 4 patients, epicardial mapping suggested VA origins in a region of low voltage that was located superior to the GCV (inaccessible area), and ablation was abandoned because of close proximity to the coronary arteries or high impedance. A right bundle-branch block, transition zone, R-wave amplitude ratio in leads III to II, Q-wave amplitude ratio in leads aVL to aVR, and S waves in lead V(6) accurately predicted the site of origin.
  
  
  CONCLUSIONS
  LV summit VAs may be ablated within the GCV or inferior to the GCV on the epicardial surface, though sites superior to the GCV are usually inaccessible to ablation.
authors.affiliation: Division of Cardiovascular Disease, University of Alabama at Birmingham, Ala 35294-0019, USA. takumi-y@fb4.so-net.ne.jp
authors.forename: Takumi
authors.initials: T
authors.lastname: Yamada
authors.forename: H Thomas
authors.initials: HT
authors.lastname: McElderry
authors.forename: Harish
authors.initials: H
authors.lastname: Doppalapudi
authors.forename: Taro
authors.initials: T
authors.lastname: Okada
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Murakami
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Naoki
authors.initials: N
authors.lastname: Yoshida
authors.forename: Yasuya
authors.initials: Y
authors.lastname: Inden
authors.forename: Toyoaki
authors.initials: T
authors.lastname: Murohara
authors.forename: Vance J
authors.initials: VJ
authors.lastname: Plumb
authors.forename: G Neal
authors.initials: GN
authors.lastname: Kay
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017115:Catheter Ablation / Q000379:methods*; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000033:anatomy & histology*; D006352:Heart Ventricles / Q000294:innervation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000503:physiopathology* / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult