title: Repolarization changes in patients with heart failure receiving cardiac resynchronization therapy-signs of cardiac memory.
abstract: OBJECTIVE
  Cardiac memory is known as T-wave inversions and other repolarization changes after a period of altered ventricular activation, previously mainly studied in structurally normal hearts. We investigated repolarization changes in failing hearts undergoing cardiac resynchronization therapy (CRT).
  
  
  METHODS
  Electrocardiogram and vectorcardiogram were recorded before and 1 day and 2 weeks after initiation of CRT in 23 patients with heart failure and left bundle-branch block.
  
  
  RESULTS
  After 1 day of CRT, the T vector during intrinsic conduction (left bundle-branch block) had rotated toward the direction of the paced QRS vector; T-vector size had increased with further increase after 2 weeks (T-vector amplitude, 889 ± 277 vs 651 ± 225 μV; T area, 169 ± 70 vs 102 ± 39 μVs; P < .01) accompanied by prolonged repolarization (T peak-to-end, 174 ± 34 vs 127 ± 16; QT interval corrected for heart rate, 541 ± 59 vs 493 ± 33 milliseconds; P < .01).
  
  
  CONCLUSIONS
  Repolarization changes are present in patients with heart failure, although less pronounced compared with after right ventricular pacing in structurally normal hearts.
authors.affiliation: Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands. liliane.wecke@karolinska.se
authors.forename: Liliane
authors.initials: L
authors.lastname: Wecke
authors.forename: Caroline J M
authors.initials: CJ
authors.lastname: van Deursen
authors.forename: Lennart
authors.initials: L
authors.lastname: Bergfeldt
authors.forename: Frits W
authors.initials: FW
authors.lastname: Prinzen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002037:Bundle-Branch Block / Q000503:physiopathology* / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric; D014672:Vectorcardiography