title: Sustained polymorphic arrhythmias induced by programmed ventricular stimulation have prognostic value in patients receiving defibrillators.
abstract: BACKGROUND
  Patients with ischemic cardiomyopathy (ICM) who have monomorphic ventricular tachycardia (VT) induced by programmed ventricular stimulation (PVS) are at increased risk of sudden cardiac death (SCD). Among a primary prevention population, the prognostic significance of induced polymorphic ventricular arrhythmias is unknown.
  
  
  METHODS
  A total of 105 consecutive patients who received an implantable cardioverter-defibrillator (ICD) for primary prevention of SCD in the setting of ICM and non-sustained VT were retrospectively evaluated. Seventy-five patients (group I) had induction of monomorphic VT and 30 patients (group II) had a sustained ventricular arrhythmia other than monomorphic VT (ventricular flutter, ventricular fibrillation, and polymorphic VT) induced during PVS.
  
  
  RESULTS
  Baseline characteristics were similar between group I and group II except for ejection fraction (25% vs. 31%, P = 0.0001) and QRS duration (123 milliseconds vs. 109 milliseconds, P = 0.04). Sixteen of 75 (21.3%) patients in group I and 6 of 30 (20%) patients in group II received appropriate ICD therapy (P = 0.88). Survival free from ICD therapy was similar between groups (P = 0.54). There was a trend toward increased all-cause mortality among patients in group I by Kaplan-Meier analysis (P = 0.08). However, when adjusted for age, EF, and QRS duration mortality was similar (P = 0.45).
  
  
  CONCLUSIONS
  There is no difference in rates of appropriate ICD discharge or mortality between patients dichotomized by type of rhythm induced during PVS. These results suggest that patients in this population who have inducible VF or sustained polymorphic VT have similar rates of subsequent clinical ventricular tachyarrhythmias as those with inducible monomorphic VT.
authors.affiliation: Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA. scottgre@hotmail.com
authors.forename: Scott L
authors.initials: SL
authors.lastname: Greenberg
authors.forename: J
authors.initials: J
authors.lastname: Mauricio Sánchez
authors.forename: Jonas A
authors.initials: JA
authors.lastname: Cooper
authors.forename: Michael E
authors.initials: ME
authors.lastname: Cain
authors.forename: Jane
authors.initials: J
authors.lastname: Chen
authors.forename: Marye J
authors.initials: MJ
authors.lastname: Gleva
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Lindsay
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Smith
authors.forename: Mitchell N
authors.initials: MN
authors.lastname: Faddis
mesh_terms: D000368:Aged; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D004554:Electric Countershock / Q000379:methods*; D004558:Electric Stimulation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000517:prevention & control*; D013813:Therapy, Computer-Assisted / Q000379:methods; D014693:Ventricular Fibrillation / Q000175:diagnosis* / Q000517:prevention & control*