title: ECG parameters predict left ventricular conduction delay in patients with left ventricular dysfunction.
abstract: Estimating left ventricular electrical delay (Q-LV) from a 12-lead ECG may be important in evaluating cardiac resynchronization therapy (CRT).
  
  
  
  The purpose of this study was to assess the impact of Q-LV interval on ECG configuration.
  
  
  
  One hundred ninety-two consecutive patients undergoing CRT implantation were divided electrocardiographically into 3 groups: left bundle branch block (LBBB), right bundle branch block (RBBB), and nonspecific intraventricular conduction delay (IVCD). The IVCD group was further subdivided into 81 patients with left (L)-IVCD and 15 patients with right (R)-IVCD (resembling RBBB, but without S wave in leads I and aVL). The Q-LV interval in the different groups and the relationship between ECG parameters and the maximum Q-LV interval were analyzed.
  
  
  
  Patients with LBBB presented a long Q-LV interval (147.7 ± 14.6 ms, all exceeding cutoff value of 110 ms), whereas RBBB patients presented a very short Q-LV interval (75.2 ± 16.3 ms, all <110 ms). Patients with an IVCD displayed a wide range of Q-LV intervals. In L-IVCD, mid-QRS notching/slurring showed the strongest correlation with a longer Q-LV interval, followed, in decreasing order, by QRS duration >150 ms and intrinsicoid deflection >60 ms. Isolated mid-QRS notching/slurring predicted Q-LV interval >110 ms in 68% of patients. The R-IVCD group presented an unexpectedly longer Q-LV interval (127.0 ± 12.5 ms; 13/15 patients had Q-LV >110 ms).
  
  
  
  Patients with LBBB have a very prolonged Q-LV interval. Mid-QRS notching in lateral leads strongly predicts a longer Q-LV interval in L-IVCD patients. Patients with R-IVCD constitute a subgroup of patients with a long Q-LV interval.
authors.affiliation: Department of Cardiology, Rovigo General Hospital, Rovigo, Italy. Electronic address: gian.past@libero.it.
authors.forename: Gianni
authors.initials: G
authors.lastname: Pastore
authors.affiliation: Department of Cardiology, Rovereto General Hospital, Rovereto, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Maines
authors.affiliation: Department of Cardiology, Rovigo General Hospital, Rovigo, Italy.
authors.forename: Lina
authors.initials: L
authors.lastname: Marcantoni
authors.affiliation: Department of Cardiology, Rovigo General Hospital, Rovigo, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Zanon
authors.affiliation: Department of Molecular Medicine, University of Padua, Padova, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Noventa
authors.affiliation: Boston Scientific Italy, Milan, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Corbucci
authors.affiliation: Department of Cardiology, Rovigo General Hospital, Rovigo, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Baracca
authors.affiliation: Department of Cardiology, Rovigo General Hospital, Rovigo, Italy.
authors.forename: Silvio
authors.initials: S
authors.lastname: Aggio
authors.affiliation: Department of Cardiology, Rovigo General Hospital, Rovigo, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Picariello
authors.affiliation: Department of Cardiology, Rovigo General Hospital, Rovigo, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Lanza
authors.affiliation: Department of Cardiology, Rovigo General Hospital, Rovigo, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Rigatelli
authors.affiliation: Department of Cardiology, Rovigo General Hospital, Rovigo, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Carraro
authors.affiliation: Department of Cardiology, Rovigo General Hospital, Rovigo, Italy.
authors.forename: Loris
authors.initials: L
authors.lastname: Roncon
authors.affiliation: Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York.
authors.forename: S Serge
authors.initials: SS
authors.lastname: Barold
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002037:Bundle-Branch Block / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006329:Heart Conduction System / Q000000981:diagnostic imaging / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D013223:Statistics as Topic; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000503:physiopathology
keywords: Cardiac resynchronization therapy; Heart failure; Left bundle branch block; Left ventricular electrical delay; Nonspecific intraventricular conduction delay; Right bundle branch block