title: T-wave area predicts response to cardiac resynchronization therapy in patients with left bundle branch block.
abstract: BACKGROUND
  Chronic heart failure patients with a left ventricular (LV) conduction delay, mostly due to left bundle branch block (LBBB), generally derive benefit from cardiac resynchronization therapy (CRT). However, 30-50% of patients do not show a clear response to CRT. We investigated whether T-wave analysis of the ECG can improve patient selection.
  
  
  RESULTS
  The study population comprised 244 CRT recipients with baseline 12-lead electrocardiogram recordings. Echocardiographic response after 6-month CRT was defined as a ≥5% increase in LV ejection fraction (LVEF). Vectorcardiograms (VCGs) were constructed from the measured 12-lead ECGs using an adapted Kors algorithm on digitized ECGs. Logistic regression models indicated repolarization variables as good predictors of CRT response. The VCG-derived T-wave area predicted CRT response (odds ratio [OR] per 10 μVs increase 1.172 [P < 0.001]) even better than QRS-wave area (OR = 1.116 [P = 0.001]). T-wave area had especially predictive value in the LBBB patient group (OR = 2.77 in LBBB vs. 1.09 in non-LBBB). This predictive value persisted after adjustment of multiple covariates, such as gender, ischemia, age, hypertension, coronary artery bypass graft, and the usage of diuretics and β-blockers. In LBBB patients, the increase in LVEF was 6.1 ± 9.7% and 11.3 ± 9.1% in patients with T-wave area below and above the median value, respectively (P < 0.01).
  
  
  CONCLUSIONS
  In patients with LBBB morphology of the QRS complex, a larger baseline T-wave area is an important independent predictor of LVEF increase following CRT.
authors.affiliation: Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands.
authors.forename: Elien B
authors.initials: EB
authors.lastname: Engels
authors.forename: Eszter M
authors.initials: EM
authors.lastname: Végh
authors.forename: Caroline J M
authors.initials: CJ
authors.lastname: Van Deursen
authors.forename: Kevin
authors.initials: K
authors.lastname: Vernooy
authors.forename: Jagmeet P
authors.initials: JP
authors.lastname: Singh
authors.forename: Frits W
authors.initials: FW
authors.lastname: Prinzen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001900:Boston; D002037:Bundle-Branch Block / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy; D058409:Cardiac Resynchronization Therapy Devices; D002908:Chronic Disease; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D018579:Patient Selection; D011237:Predictive Value of Tests; D020127:Recovery of Function; D012189:Retrospective Studies; D012815:Signal Processing, Computer-Assisted; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D014672:Vectorcardiography; D016277:Ventricular Function, Left
keywords: T wave; biventricular pacing; cardiac resynchronization therapy; electrocardiography; heart failure; left bundle branch block