title: Defective recovery of QT dispersion predicts late cardiac mortality after percutaneous coronary intervention.
abstract: BACKGROUND
  It has been suggested that corrected QT dispersion (cQTD) provides a measure of repolarisation inhomogeneity; however, the existence of a relationship between cQTD and cardiac outcomes is controversial.
  
  
  OBJECTIVE
  To assess whether changes in cQTD following percutaneous coronary intervention (PCI) predict long-term survival.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Single tertiary care centre. Main outcome measures Cardiac mortality.
  
  
  METHODS
  612 patients had a 12-lead ECG recorded before and 6 h after PCI, and were followed-up for 49 ± 10 months.
  
  
  RESULTS
  PCI was associated with a significant overall reduction of cQTD at 6 h versus baseline (p < 0.001); a reduction in cQTD occurred in 343 patients (56%). During the follow-up, 46 deaths (7.5%) were recorded, 21 of which for non-cardiac and 25 for cardiac causes. At Cox regression analysis, a reduced ΔcQTD (cQTD baseline - 6 h) was an independent predictor of cardiac mortality (HR = 1.497; 95% CI 1.081 to 2.075 for each 20 ms decrease; p = 0.015), together with age (HR = 1.672; 95% CI 1.039 to 2.691 per 10 years increase; p = 0.034), diabetes (HR = 2.622; 95% CI 1.112 to 6.184; p=0.028), peak CK-MB (HR = 1.798; 95% CI 1.063 to 3.039 per each unit increase over normal level; p = 0.029), three-vessel coronary artery disease (HR=3.626; 95% CI 1.079 to 12.187; p = 0.037) and the number of treated lesions (HR=2.066; 95% CI 1.208 to 3.532; p = 0.008). Patients in the lowest tertile of ΔcQTD and having a post-procedural increase of CK-MB had a considerably higher cardiac mortality than the remaining population (14.6 vs 2.4%, p < 0.001).
  
  
  CONCLUSIONS
  cQTD decreases after PCI. A defective cQTD recovery, suggesting the persistence of repolarisation inhomogeneities, predicts long-term cardiac mortality.
authors.affiliation: Institute of Cardiology and Center of Excellence on Ageing, G. d'Annunzio University, Chieti, Ospedale SS. Annunziata, Via dei Vestini, 30, Chieti 66013, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Zimarino
authors.forename: Alessandro
authors.initials: A
authors.lastname: Corazzini
authors.forename: Alfonso
authors.initials: A
authors.lastname: Tatasciore
authors.forename: Stefania
authors.initials: S
authors.lastname: Marazia
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Torge
authors.forename: Cesare
authors.initials: C
authors.lastname: Di Iorio
authors.forename: Raffaele
authors.initials: R
authors.lastname: De Caterina
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015906:Angioplasty, Balloon, Coronary; D003327:Coronary Disease / Q000503:physiopathology / Q000628:therapy*; D004562:Electrocardiography / Q000379:methods; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016896:Treatment Outcome