title: Distinguishing ventricular arrhythmia originating from the right coronary cusp, peripulmonic valve area, and the right ventricular outflow tract: utility of lead I.
abstract: BACKGROUND
  Outflow tract ventricular arrhythmia (OTVA) can be complicated to target for ablation when originating from either the periaortic or pulmonary valve (PV) region. Both sites may present with a small R wave in lead V1. However, the utility of lead I in distinguishing these arrhythmia locations is unknown.
  
  
  RESULTS
  Thirty-six consecutive patients (mean age 41 ± 14 years, 13 male) underwent catheter ablation for OTVA. OTVA origin was determined from intracardiac electrogram tracings and electroanatomic maps. Observers blinded to results measured QRS waveform amplitude and duration from standard 12-lead ECG tracings. Measurements with highest diagnostic performance were modeled into an algorithm. Sites of successful ablation were anterior right ventricular outflow tract (RVOT; n = 6), posterior RVOT (n = 4), PV (n = 18), and right coronary cusp (RCC; n = 8). Highest performing surface ECG discriminators were from lead I to V1 vectors: RCC, lead I R wave ≥ 1.5 mV, and V1 R wave ≥2.0 mV (sensitivity 87%, specificity 93%); PV, V1 R wave > 0 mV, and lead I R/(R+S) ≤ 0.75 (sensitivity 78%, specificity 72%); anterior RVOT, V1 R wave = 0 mV, and lead I R/(R+S) <0.4 (sensitivity 67%, specificity 97%); posterior RVOT, V1 R wave > 0 mV, and lead I R/(R+S) > 0.75 (sensitivity 75%, specificity 84%). Sequential algorithmic application of these criteria resulted in an overall accuracy of 72% in predicting site of OTVA origin.
  
  
  CONCLUSIONS
  A relatively large R wave in lead I is seen with RCC origin but not PV origin. A sequential algorithm has limited but potentially significant value beyond assessment of lead I in approaching OTVA.
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Elisa
authors.initials: E
authors.lastname: Ebrille
authors.affiliation: Carnegie Mellon, Pittsburg, Pennsylvania, USA.
authors.forename: Vishnu M
authors.initials: VM
authors.lastname: Chandra
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Faisal
authors.initials: F
authors.lastname: Syed
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Freddy
authors.initials: F
authors.lastname: Del Carpio Munoz
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Sudip
authors.initials: S
authors.lastname: Nanda
authors.affiliation: Division of Cardiology, Department of Medicine, Queen Mary Hospital, Hong Kong.
authors.forename: Jo Jo
authors.initials: JJ
authors.lastname: Hai
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Cha
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Hammill
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Munger
authors.affiliation: Mayo Clinic Jacksonville Florida, Division of Cardiology, Jacksonville, Florida, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Venkatachalam
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Packer
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.|Department of Pediatrics and Adolescent Medicine Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Asirvatham
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D017115:Catheter Ablation; D003331:Coronary Vessels / Q000503:physiopathology*; D003937:Diagnosis, Differential; D004562:Electrocardiography / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011664:Pulmonary Valve / Q000503:physiopathology*; D018754:Ventricular Dysfunction / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D014694:Ventricular Outflow Obstruction / Q000503:physiopathology* / Q000601:surgery
keywords: catheter ablation; outflow tract; premature ventricular contractions; right coronary cusp; sinus of Valsalva; ventricular tachycardia