title: Prospective Use of Microvolt T-Wave Alternans Testing to Guide Primary Prevention Implantable Cardioverter Defibrillator Therapy.
abstract: BACKGROUND
  We hypothesized that a negative microvolt T-wave alternans (MTWA) test would identify patients unlikely to benefit from primary prevention implantable cardioverter defibrillator (ICD) therapy in a prospective cohort.
  
  
  RESULTS
  Data were pooled from 8 centers where MTWA testing was performed specifically for the purpose of guiding primary prevention ICD implantation. Cohorts were included if the ratio of ICDs implanted in patients who were MTWA "non-negative" to patients who were MTWA negative was >2:1, indicating that MTWA testing had a significant impact on the decision to implant an ICD. The pooled cohort included 651 patients: 371 MTWA non-negative and 280 MTWA negative. Among non-negative patients, 62% underwent ICD implantation whereas only 13% of MTWA-negative patients received an ICD (P<0.01). Despite a substantially lower prevalence of ICDs, long-term survival (6.9 years) was significantly better among MTWA-negative patients (68.2% non-negative vs. 87.1% negative, P=0.026).
  
  
  CONCLUSIONS
  MTWA-negative patients had significantly better survival than MTWA non-negative patients, the majority of whom had ICDs. Despite a very low prevalence of ICDs, long-term survival among patients with left ventricular ejection fraction ≤40% and a negative MTWA test was better than in the ICD arm of any study to date that has demonstrated a benefit of ICDs. This provides further evidence that MTWA-negative patients are unlikely to benefit from primary prevention ICD therapy.
authors.affiliation: Cardiology Division, Emory University School of Medicine.
authors.forename: Faisal M
authors.initials: FM
authors.lastname: Merchant
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Salerno-Uriarte
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Caravati
authors.forename: Stefania
authors.initials: S
authors.lastname: Falcone
authors.forename: Giulio
authors.initials: G
authors.lastname: Molon
authors.forename: Daniele
authors.initials: D
authors.lastname: Marangoni
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Raczak
authors.forename: Ludmila
authors.initials: L
authors.lastname: Danilowicz-Szymanowicz
authors.forename: Roberto F E
authors.initials: RF
authors.lastname: Pedretti
authors.forename: Simona
authors.initials: S
authors.lastname: Sarzi Braga
authors.forename: Takanori
authors.initials: T
authors.lastname: Ikeda
authors.forename: Leonardo
authors.initials: L
authors.lastname: Calo
authors.forename: Annamaria
authors.initials: A
authors.lastname: Martino
authors.forename: Demet
authors.initials: D
authors.lastname: Erciyes
authors.forename: Maurizio
authors.initials: M
authors.lastname: Piancastelli
authors.forename: Philippe
authors.initials: P
authors.lastname: Maury
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cohen
authors.forename: Antonis A
authors.initials: AA
authors.lastname: Armoundas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000401:mortality* / Q000628:therapy*; D017147:Defibrillators, Implantable; D018572:Disease-Free Survival; D004554:Electric Countershock; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015996:Survival Rate