title: Left Ventricular Outflow Tract Arrhythmias: Clinical Characteristics and Site of Origin.
abstract: BACKGROUND
  Left ventricular outflow tract (LVOT) arrhythmias are increasingly recognized. Data regarding the distribution of the sites of origin (SOO) of the arrhythmias are sparse.
  
  
  OBJECTIVE
  To describe the clinical characteristics of patients with LVOT arrhythmias and the distribution of their SOO.
  
  
  METHODS
  All 42 consecutive patients with LVOT arrhythmias who underwent radiofrequency (RF) ablation during the period 2000-2014 were included. SOO identification was based on mapping activation, pace mapping and a 3D mapping system in eight patients.
  
  
  RESULTS
  The study group comprised 28 males (66.7%) and 14 females, the mean age was 55 ± 15.4 years. Most patients (76%) were symptomatic. All suffered from high grade ventricular arrhythmias. Left ventricular (LV) dysfunction (ejection fraction ≤ 50%) was observed in 15 patients (35.7%), of whom 14 (93.3%) were males. The left coronary cusp (LCC) was the most common arrhythmia SOO (64.3%). Other locations were the right coronary cusp (RCC), the junction of the RCC-LCC commissure, aortic-mitral continuity, endocardial-LVOT, and a coronary sinus branch. Acute successful ablation was achieved in 29 patients (69%) and transient arrhythmia abolition in 40 (95.2%). There was a trend for a higher success rate using cooled tip ablation catheters as compared to standard catheters. The ablation procedure significantly improved LV function in all patients with tachycardiomyopathy.
  
  
  CONCLUSIONS
  LVOT arrhythmias mostly originate from the LCC and are associated with LV dysfunction in 36% of patients. Knowledge regarding the prevalence of the anatomic origin of the LVOT arrhythmias may help achieve successful ablation. The use of cooled tip ablation catheters might have beneficial effects on the success rate of the procedure.
authors.forename: Oholi
authors.initials: O
authors.lastname: Tovia-Brodie
authors.forename: Yoav
authors.initials: Y
authors.lastname: Michowitz
authors.forename: Aharon
authors.initials: A
authors.lastname: Glick
authors.forename: Raphael
authors.initials: R
authors.lastname: Rosso
authors.forename: Bernard
authors.initials: B
authors.lastname: Belhassen
mesh_terms: D000328:Adult; D000368:Aged; D017115:Catheter Ablation / Q000379:methods*; D015331:Cohort Studies; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000503:physiopathology* / Q000601:surgery; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology* / Q000601:surgery