title: Ventricular tachyarrhythmia recurrence in primary versus secondary implantable cardioverter-defibrillator patients and role of electrophysiology study.
abstract: OBJECTIVE
  In recent years, there has been a shift away from performing electrophysiologic study (EPS) to guide implantable cardioverter-defibrillator (ICD) implantation with a reliance on left ventricular ejection fraction (LVEF) alone.
  
  
  METHODS
  ICD patients were prospectively recruited from the multicentre COMFORT (Concept of Optimal Management of ventricular Fibrillation Or Very fast ventricular Tachycardia) trial. Primary prevention ICD patients (n = 260, groups 1 and 2) were compared to secondary prevention ICD patients (n = 210, group 3). Primary prevention ICDs were implanted in patients with ischemic cardiomyopathy based on LVEF ≤ 40 % and inducible ventricular tachycardia (VT) at EPS (n = 123, group 1) or impaired LVEF alone (LVEF ≤ 30 % or LVEF ≤ 35 % with NYHA class II or III; n = 137, group 2). EPS was performed in 61 % of secondary prevention ICD patients (n = 129). Patients were followed up for >12 months with a primary endpoint of spontaneous VT/ventricular fibrillation (VF).
  
  
  RESULTS
  A significantly higher rate of spontaneous VT/VF occurred in secondary versus primary prevention ICD patients (P < 0.001) and in EPS-guided versus LVEF-guided primary prevention ICD patients (P = 0.029). At 2 years, the proportion of patients with ≥1 VT/VF episode was 24.6 ± 4.2 %, 19.9 ± 4.6 % and 37.1 ± 3.9 % for groups 1, 2 and 3, respectively. In the secondary prevention, patients who underwent EPS, VT/VF occurred in 44.4 ± 5.9 % and 14.1 ± 6.6 % with a positive versus negative result, respectively (P = 0.02).
  
  
  CONCLUSIONS
  Secondary prevention ICD patients have more spontaneous VT/VF than primary prevention ICD patients. Secondary and primary prevention ICD patients with inducible VT at EPS have more VT/VF than patients without inducible VT or impaired LVEF alone.
authors.affiliation: Department of Cardiology, Westmead Hospital, Sydney, NSW, 2145, Australia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Zaman
authors.forename: Gopal
authors.initials: G
authors.lastname: Sivagangabalan
authors.forename: William
authors.initials: W
authors.lastname: Chik
authors.forename: Wayne
authors.initials: W
authors.lastname: Stafford
authors.forename: John
authors.initials: J
authors.lastname: Hayes
authors.forename: Russell
authors.initials: R
authors.lastname: Denman
authors.forename: Glenn
authors.initials: G
authors.lastname: Young
authors.forename: Prashanthan
authors.initials: P
authors.lastname: Sanders
authors.forename: Pramesh
authors.initials: P
authors.lastname: Kovoor
mesh_terms: D001315:Australia / Q000453:epidemiology; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D018572:Disease-Free Survival; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011322:Primary Prevention / Q000706:statistics & numerical data*; D012008:Recurrence; D012307:Risk Factors; D055502:Secondary Prevention / Q000706:statistics & numerical data*; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*