title: Empiric versus imaging guided left ventricular lead placement in cardiac resynchronization therapy (ImagingCRT): study protocol for a randomized controlled trial.
abstract: BACKGROUND
  Cardiac resynchronization therapy (CRT) is an established treatment in heart failure patients. However, a large proportion of patients remain nonresponsive to this pacing strategy. Left ventricular (LV) lead position is one of the main determinants of response to CRT. This study aims to clarify whether multimodality imaging guided LV lead placement improves clinical outcome after CRT.
  
  
  METHODS
  The ImagingCRT study is a prospective, randomized, patient- and assessor-blinded, two-armed trial. The study is designed to investigate the effect of imaging guided left ventricular lead positioning on a clinical composite primary endpoint comprising all-cause mortality, hospitalization for heart failure, or unchanged or worsened functional capacity (no improvement in New York Heart Association class and <10% improvement in six-minute-walk test). Imaging guided LV lead positioning is targeted to the latest activated non-scarred myocardial region by speckle tracking echocardiography, single-photon emission computed tomography, and cardiac computed tomography. Secondary endpoints include changes in LV dimensions, ejection fraction and dyssynchrony. A total of 192 patients are included in the study.
  
  
  CONCLUSIONS
  Despite tremendous advances in knowledge with CRT, the proportion of patients not responding to this treatment has remained stable since the introduction of CRT. ImagingCRT is a prospective, randomized study assessing the clinical and echocardiographic effect of multimodality imaging guided LV lead placement in CRT. The results are expected to make an important contribution in the pursuit of increasing response rate to CRT.
  
  
  BACKGROUND
  Clinicaltrials.gov identifier NCT01323686. The trial was registered March 25, 2011 and the first study subject was randomized April 11, 2011.
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Brendstrupgaardsvej 100, Skejby DK-8200, Aarhus N, Denmark. a.sommer@dadlnet.dk
authors.forename: Anders
authors.initials: A
authors.lastname: Sommer
authors.forename: Mads Brix
authors.initials: MB
authors.lastname: Kronborg
authors.forename: Steen Hvitfeldt
authors.initials: SH
authors.lastname: Poulsen
authors.forename: Morten
authors.initials: M
authors.lastname: Böttcher
authors.forename: Bjarne Linde
authors.initials: BL
authors.lastname: Nørgaard
authors.forename: Kirsten
authors.initials: K
authors.lastname: Bouchelouche
authors.forename: Peter Thomas
authors.initials: PT
authors.lastname: Mortensen
authors.forename: Christian
authors.initials: C
authors.lastname: Gerdes
authors.forename: Jens Cosedis
authors.initials: JC
authors.lastname: Nielsen
mesh_terms: D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D058409:Cardiac Resynchronization Therapy Devices; D002985:Clinical Protocols; D003718:Denmark; D003952:Diagnostic Imaging / Q000379:methods; D018450:Disease Progression; D004311:Double-Blind Method; D015150:Echocardiography, Doppler; D005080:Exercise Test; D017079:Exercise Tolerance; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006760:Hospitalization; D006801:Humans; D011237:Predictive Value of Tests; D011446:Prospective Studies; D020127:Recovery of Function; D012107:Research Design; D013318:Stroke Volume; D013813:Therapy, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D016277:Ventricular Function, Left