title: Electrical resynchronization induced by direct His-bundle pacing.
abstract: BACKGROUND
  Biventricular pacing (BiV) to effect cardiac resynchronization therapy can be technically difficult and fails to elicit a clinical response in 30% to 40% of patients. Direct His-bundle pacing (DHBP) theoretically could obviate some of these problems. Although DHBP is capable of narrowing the QRS in some patients, the consistency with which this can be achieved has not been characterized.
  
  
  OBJECTIVE
  The purpose of this study was to restore His-Purkinje functionality in consecutive patients undergoing de novo clinically mandated cardiac resynchronization therapy.
  
  
  METHODS
  DHBP was temporarily implemented at the time of implantation of a permanent BiV system in patients referred for cardiac resynchronization therapy. Native conduction, DHBP, and BiV QRS duration were compared. All patients presenting for BiV cardiac resynchronization therapy were eligible for the study. Ten patients were studied.
  
  
  RESULTS
  DHBP was successfully implemented in all 10 patients. In 7 of 10 patients, DHBP narrowed the QRS significantly compared with native conduction and BiV (mean QRS duration: native 171 +/- 13 ms, DHBP 148 +/- 11 ms, BiV 158 +/- 21, P <.0001). QRS narrowing with DHBP was specifically attributable to capture of latent His-Purkinje tissue. DHBP lead implantation time (16 minutes) was shorter than standard left ventricular lead implantation time (42 minutes).
  
  
  CONCLUSIONS
  DHBP was readily implemented in patients with standard indications for BiV cardiac resynchronization therapy. In most patients studied, DHBP resulted in a significantly narrower QRS compared with native conduction. DHBP may offer a physiologic alternative to BiV for cardiac resynchronization therapy.
authors.affiliation: Cardiovascular Research Institute, Burlington, Vermont, USA. daniel.lustgarten@vtmednet.org.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Lustgarten
authors.forename: Susan
authors.initials: S
authors.lastname: Calame
authors.forename: Eric M
authors.initials: EM
authors.lastname: Crespo
authors.forename: James
authors.initials: J
authors.lastname: Calame
authors.forename: Robert
authors.initials: R
authors.lastname: Lobel
authors.forename: Peter S
authors.initials: PS
authors.lastname: Spector
mesh_terms: D002036:Bundle of His; D002037:Bundle-Branch Block / Q000503:physiopathology / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D005240:Feasibility Studies; D006801:Humans; D011689:Purkinje Cells; D013318:Stroke Volume; D016277:Ventricular Function, Left