title: Defective recovery of QT dispersion following transcatheter aortic valve implantation: frequency, predictors and prognosis.
abstract: BACKGROUND
  Corrected QT dispersion (cQTD) has been correlated with non-uniform ventricular repolarisation and increased mortality. In patients with aortic stenosis, cQTD has been shown improved after surgical valve replacement, but the effects of transcatheter aortic valve implantation (TAVI) are unknown. Therefore, we sought to explore the frequency, predictors and prognostic effects of defective cQTD recovery at 6 months after TAVI.
  
  
  METHODS
  A total of 222 patients underwent TAVI with the Medtronic-CoreValve System between November 2005 and January 2012. Patients who were on class I or III antiarrhythmics or on chronic haemodialysis or who developed atrial fibrillation, a new bundle branch block or became pacemaker dependent after TAVI were excluded. As a result, pre-, post- and follow-up ECG (median: 6 months) analysis was available in 45 eligible patients. Defective cQTD recovery was defined as any progression beyond the baseline cQTD at 6 months.
  
  
  RESULTS
  In the 45 patients, the mean cQTD was 47 ± 23 ms at baseline, 45 ± 17 ms immediately after TAVI and 40 ± 16 ms at 6 months (15% reduction, P = 0.049). Compared to baseline, cQTD at 6 months was improved in 60% of the patients whereas defective cQTD recovery was present in 40%. cQTD increase immediately after TAVI was an independent predictor of defective cQTD recovery at 6 months (per 10 ms increase; OR: 1.89, 95% CI: 1.15-3.12). By univariable analysis, defective cQTD recovery was associated with late mortality (HR: 1.52, 95% CI: 1.05-2.17).
  
  
  CONCLUSIONS
  Despite a gradual reduction of cQTD after TAVI, 40% of the patients had defective recovery at 6 months which was associated with late mortality. More detailed ECG analysis after TAVI may help to avoid late death.
authors.affiliation: Department of Cardiology, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: Rutger-Jan
authors.initials: RJ
authors.lastname: Nuis
authors.affiliation: Department of Electrophysiology, Erasmus Thoraxcenter, Rotterdam, the Netherlands.
authors.forename: Gokhan
authors.initials: G
authors.lastname: Turgut
authors.affiliation: Department of Cardiology, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: Robert M
authors.initials: RM
authors.lastname: van der Boon
authors.affiliation: Department of Cardiology, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: Nicolas M
authors.initials: NM
authors.lastname: van Mieghem
authors.affiliation: Department of Cardiology, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: Sjoerd T
authors.initials: ST
authors.lastname: Nauta
authors.affiliation: Department of Cardiology, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Serruys
authors.affiliation: Department of Biostatistics, Erasmus Thoraxcenter, Rotterdam, the Netherlands.
authors.forename: Ron T
authors.initials: RT
authors.lastname: van Domburg
authors.affiliation: Division of Cardiovascular Diseases, Azienda Ospedaliero-Universitaria Pisana, Pisa, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Zuchelli
authors.affiliation: Department of Electrophysiology, Erasmus Thoraxcenter, Rotterdam, the Netherlands.
authors.forename: Luc
authors.initials: L
authors.lastname: Jordaens
authors.affiliation: Department of Cardiology, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: Peter P
authors.initials: PP
authors.lastname: de Jaegere
keywords: Aortic stenosis; Conduction abnormalities; Left bundle branch block; Predictors; QT dispersion; Transcatheter aortic valve implantation