title: Incidence, determinants, and prognostic implications of true pleomorphism of ventricular tachycardia in patients with implantable cardioverter-defribillators: a substudy of the DATAS Trial.
abstract: BACKGROUND
  The occurrence of monomorphic ventricular tachycardia (M-VT) with >1 QRS morphology during the same episode (pleomorphism [PL]) or in different episodes (multiple morphologies [MM]) has been described through ECG. Implantable cardioverter-defribillator (ICD) electrograms (EGs) provide the opportunity to analyze virtually all spontaneous M-VT episodes. We sought to study the incidence, determinants, and prognostic significance of PL and MM as assessed by ICD-EG in a prospective series of patients with ICDs.
  
  
  RESULTS
  Spontaneous episodes of M-VT were analyzed before ICD intervention. PL was defined as >1 ICD-EG morphology, each having ≥6 consecutive identical beats during the same VT episode, and MM as >1 ICD-EG morphology in different M-VT episodes in the same patient. We analyzed 1881 M-VT episodes from 315 patients followed for 17 months. PL and MM occurred in 6% and 19%, respectively, of the total population (16% and 62% of patients with M-VT). Recurrent M-VT as diagnosis for ICD indication predicted PL and MM. Patients with PL more frequently developed MM (85% versus 15%; P<0.001) compared to patients without PL. Total mortality (5%) was significantly higher in patients with PL (20%), in patients with MM (11.5%), and in women (12%). In multivariate analysis, only PL (odds ratio, 5.33; P=0.009) and female sex (odds ratio, 3.1; P=0.038) predicted mortality.
  
  
  CONCLUSIONS
  In a prospective series of patients with ICDs, mostly indicated for secondary prevention, both PL and MM of VT, as judged by ICD-EG, were not uncommon and were strongly associated. Female sex and the development of PL VT were the only independent predictors of mortality.
authors.affiliation: Hospital Gregorio Marañon, Madrid, Spain.
authors.forename: Claudio
authors.initials: C
authors.lastname: Hadid
authors.forename: Jesus
authors.initials: J
authors.lastname: Almendral
authors.forename: Mercedes
authors.initials: M
authors.lastname: Ortiz
authors.forename: Joerg Otto
authors.initials: JO
authors.lastname: Schwab
authors.forename: Sabine
authors.initials: S
authors.lastname: Janko
authors.forename: Karl
authors.initials: K
authors.lastname: Mischke
authors.forename: Fernando
authors.initials: F
authors.lastname: Arribas
authors.forename: Christian
authors.initials: C
authors.lastname: Wolpert
authors.forename: Renato
authors.initials: R
authors.lastname: Ricci
authors.forename: Pedro
authors.initials: P
authors.lastname: Adragao
authors.forename: Erik
authors.initials: E
authors.lastname: Cobo
authors.forename: Xavier
authors.initials: X
authors.lastname: Navarro
authors.forename: Aurelio
authors.initials: A
authors.lastname: Quesada
mesh_terms: D000368:Aged; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009026:Mortality; D015999:Multivariate Analysis; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D017180:Tachycardia, Ventricular / Q000453:epidemiology / Q000503:physiopathology* / Q000628:therapy*