title: Electrical remodelling in patients with iatrogenic left bundle branch block.
abstract: OBJECTIVE
  Left bundle branch block (LBBB) is induced in approximately one-third of all transcatheter aortic valve implantation (TAVI) procedures. We investigated electrophysiological remodelling in patients with TAVI-induced LBBB.
  
  
  RESULTS
  This retrospective study comprises 107 patients with initially narrow QRS complex of whom 40 did not and 67 did develop persistent LBBB after TAVI. 12-lead electrocardiograms (ECGs) taken before TAVI, within 24 hours ('acute'), and 1-12 months after TAVI ('chronic') were used to reconstruct vectorcardiograms. From these vectorcardiograms, QRS and T-wave area were calculated as comprehensive indices of depolarization and repolarization abnormalities, respectively. TAVI-induced LBBB resulted in significant acute depolarization and repolarization changes while further repolarization changes were observed with longer lasting LBBB. The amount of long-term repolarization changes (remodelling) was highly variable between patients. The change in T-wave area between acute and chronic LBBB ranged from +57% to - 77%. After dividing the LBBB cohort into tertiles based on the change in T-wave area, only baseline QRS area was larger in the tertile with no significant change in T-wave area. During longer lasting LBBB, the spatial vector gradient (SVG) changed orientation towards the direction of the QRS-vector, indicating that later-activated regions developed shorter action potential duration.
  
  
  CONCLUSIONS
  This study in patients with TAVI-induced LBBB shows that repolarization changes develop within months after onset of LBBB, and that these changes are highly variable between individual patients.
authors.affiliation: Department of Physiology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands.
authors.forename: Elien B
authors.initials: EB
authors.lastname: Engels
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Thomas T
authors.initials: TT
authors.lastname: Poels
authors.affiliation: Catharina Hospital, Eindhoven, The Netherlands.
authors.forename: Patrick
authors.initials: P
authors.lastname: Houthuizen
authors.affiliation: Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Peter P T
authors.initials: PP
authors.lastname: de Jaegere
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Jos G
authors.initials: JG
authors.lastname: Maessen
authors.affiliation: Department of Cardiology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Kevin
authors.initials: K
authors.lastname: Vernooy
authors.affiliation: Department of Physiology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands frits.prinzen@maastrichtuniversity.nl.
authors.forename: Frits W
authors.initials: FW
authors.lastname: Prinzen
mesh_terms: D000200:Action Potentials; D000368:Aged; D000369:Aged, 80 and over; D002036:Bundle of His / Q000503:physiopathology*; D002037:Bundle-Branch Block / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate; D006801:Humans; D007049:Iatrogenic Disease; D008297:Male; D008955:Models, Cardiovascular; D009426:Netherlands; D066230:Patient-Specific Modeling; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors; D065467:Transcatheter Aortic Valve Replacement / Q000009:adverse effects*; D014672:Vectorcardiography
keywords: Left bundle branch block • Transcatheter aortic valve implantation • Vectorcardiography • Electrical remodelling