title: Relationship between mechanical dyssynchrony and intra-operative electrical delay times in patients undergoing cardiac resynchronization therapy.
abstract: BACKGROUND
  It is important to understand the relationship between electrical and mechanical ventricular activation in CRT patients. By measuring local electrical activation at multiple locations within the coronary veins and myocardial contraction at the same locations in the left ventricle, we determined the relationship between electrical and mechanical activation at potential left ventricular pacing locations.
  
  
  METHODS
  In this study, mechanical contraction times were computed using high temporal resolution cine cardiovascular magnetic resonance (CMR) data, while electrical activation times were derived from intra-procedural local electrograms.
  
  
  RESULTS
  In our cohort, there was a strong correlation between electrical and mechanical delay times within each patient (R2=0.78 ± 0.23). Additionally, the latest electrically activated location corresponded with the latest mechanically contracting location in 91% of patients.
  
  
  CONCLUSIONS
  This study provides initial evidence that our method of obtaining non-invasive mechanical activation patterns accurately reflects the underlying electromechanical substrate of intraventricular dyssynchrony.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Suever
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Hartlage
authors.forename: R Patrick
authors.initials: RP
authors.lastname: Magrath
authors.forename: Shahriar
authors.initials: S
authors.lastname: Iravanian
authors.forename: Michael S
authors.initials: MS
authors.lastname: Lloyd
authors.affiliation: Wallace H, Coulter Department of Biomedical Engineering, Georgia Institute of Technology / Emory University, 1364 Clifton Road, Suite AG30, Atlanta, GA 30322, USA. jnoshin@emory.edu.
authors.forename: John N
authors.initials: JN
authors.lastname: Oshinski
mesh_terms: D000200:Action Potentials; D058406:Cardiac Resynchronization Therapy; D017023:Coronary Angiography; D004562:Electrocardiography; D006329:Heart Conduction System / Q000503:physiopathology*; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D009200:Myocardial Contraction; D011237:Predictive Value of Tests; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D016277:Ventricular Function, Left