title: Ventricular premature depolarizations triggered by incremental dose isoproterenol infusion: common electrocardiographic features.
abstract: OBJECTIVE
  To identify the prevalence of adrenergically mediated ventricular premature depolarizations (VPDs) and characterize their electrocardiographic (ECG) features and specific anatomically determined sites of origin within the ventricles.
  
  
  METHODS
  VPDs occurring during incremental isoproterenol infusion (3 to 20 mug/min) in 108 patients (30 women, mean age 58 +/- 10 years) with normal ventricular function and no previous ventricular tachycardia (VT) were identified. VPDs were grouped to a probable anatomic region of origin based on 12-lead ECG.
  
  
  RESULTS
  The 235 VPD morphologies (median 2 per patient, range 1-13) were observed in 85/108 (79%) patients. The most frequent regions of origin were: peri-mitral annulus 17%, left-Purkinje network 14%, right ventricle (RV) outflow tract 14%, apical RV free wall 11% and peri-tricuspid annulus 10%. Only 39 (17%) VPDs were not easily classified.
  
  
  CONCLUSIONS
  Adrenergically mediated VPDs are frequent in patients without structural heart disease or VT and tend to originate from a few anatomic sites.
authors.affiliation: Cardiovascular Division, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Nuria
authors.initials: N
authors.lastname: Rivas
authors.forename: Sandhya
authors.initials: S
authors.lastname: Dhruvakumar
authors.forename: Sumeet K
authors.initials: SK
authors.lastname: Mainigi
authors.forename: Tanya
authors.initials: T
authors.lastname: Smith
authors.forename: Edward P
authors.initials: EP
authors.lastname: Gerstenfeld
authors.forename: Francis E
authors.initials: FE
authors.lastname: Marchlinski
mesh_terms: D000328:Adult; D002316:Cardiotonic Agents / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D006801:Humans; D007545:Isoproterenol / Q000009:adverse effects*; D018879:Ventricular Premature Complexes / Q000139:chemically induced* / Q000175:diagnosis*
chemical_list: D002316:Cardiotonic Agents; D007545:Isoproterenol