title: QRS integral: an electrocardiographic indicator of mechanical interventricular asynchrony.
abstract: OBJECTIVE
  The aim of this study was to investigate whether interventricular asynchrony (IVA) can be measured by electrocardiography.
  
  
  METHODS
  Sixty-two patients (New York Heart Association heart failure functional class III: age, mean +/- SD: 64 +/- 9 years; ejection fraction, mean +/- SD: 24% +/- 8%; dilative cardiomyopathy/ischemic cardiomyopathy, n = 39/23) with left bundle branch block (QRS duration, mean +/- SD: 165 +/- 21 milliseconds) underwent a 120-channel body surface mapping. QRS integral was analyzed and compared with IVA (echo).
  
  
  RESULTS
  Interventricular asynchrony was associated with significantly decreased QRS integrals 15 cm cranial and 6 cm lateral from V1 in patients with normal axis (n = 36): At a cutoff value of -26 milliseconds mV, receiver operating characteristic analysis to predict IVA revealed a sensitivity of 89% and a specificity of 83% (area under curve, mean +/- SEM: 0.9 +/- 0.07; P < .001). In patients with left axis deviation (n = 26), IVA showed significantly decreased QRS integrals 10 cm caudal from V1: at a cutoff value of -89 milliseconds mV, receiver operating characteristic analysis to predict IVA revealed a sensitivity of 83% and a specificity of 100% (area under curve, mean +/- SEM: 0.9 +/- 0.07; P < .002).
  
  
  CONCLUSIONS
  Interventricular asynchrony strongly correlates with QRS integral. Key lead positions, however, are axis dependent and outside standard leads.
authors.affiliation: Department of Cardiology and Angiology, University Hospital of Muenster, Albert-Schweitzer-Strasse 33, Münster, Germany. alexander.samol@ukmuenster.de
authors.forename: Alexander
authors.initials: A
authors.lastname: Samol
authors.forename: Stefan
authors.initials: S
authors.lastname: Klotz
authors.forename: Jörg
authors.initials: J
authors.lastname: Stypmann
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Bruns
authors.forename: Richard
authors.initials: R
authors.lastname: Houben
authors.forename: Matthias
authors.initials: M
authors.lastname: Paul
authors.forename: Christian
authors.initials: C
authors.lastname: Vahlhaus
mesh_terms: D000465:Algorithms; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis*