title: Universal algorithm for diagnosis of biventricular capture in patients with cardiac resynchronization therapy.
abstract: BACKGROUND
  An accurate and universal method for diagnosis of biventricular (BiV) capture using a standard 12-lead electrocardiogram (ECG) would be useful for assessment of cardiac resynchronization therapy (CRT) patients. Our objective was to develop and validate such an ECG method for BiV capture diagnosis that would be independent of pacing lead positions-a major confounder that significantly influences the morphologies of paced QRS complexes.
  
  
  METHODS
  On the basis of an evaluation of 789 ECGs of 443 patients with heart failure and various right ventricular (RV) and left ventricular (LV) lead positions, the following algorithm was constructed and validated. BiV capture was diagnosed if the QRS in lead I was predominantly negative and either V1 QRS was predominantly positive or V6 QRS was of negative onset and predominantly negative (step 1), or if QRS complex duration was <160 ms (step 2). All other ECGs were classified as loss of LV capture.
  
  
  RESULTS
  The algorithm showed good accuracy (93%), sensitivity (97%), and specificity (90%) for detection of loss of LV capture. The performance of the algorithm did not differ among apical, midseptal, and outflow tract RV lead positions and various LV lead positions.
  
  
  CONCLUSIONS
  LV capture leaves diagnostic hallmarks in the fused BiV QRS related to different vectors of depolarization and more rapid depolarization of the ventricles. An accurate two-step ECG algorithm for BiV capture diagnosis was developed and validated. This algorithm is universally applicable to all CRT patients, regardless of the positions of the pacing leads.
authors.affiliation: First Department of Cardiology, Interventional Electrocardiology and Hypertension, University Hospital, Cracow, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Jastrzebski
authors.forename: Piotr
authors.initials: P
authors.lastname: Kukla
authors.forename: Kamil
authors.initials: K
authors.lastname: Fijorek
authors.forename: Danuta
authors.initials: D
authors.lastname: Czarnecka
mesh_terms: D000368:Aged; D000465:Algorithms; D058406:Cardiac Resynchronization Therapy; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000628:therapy*; D006801:Humans; D008297:Male
keywords: biventricular pacing; cardiac resynchronization therapy; electrocardiogram; left ventricular capture; pacing lead position