title: A clinical feasibility study of atrial and ventricular electromechanical wave imaging.
abstract: BACKGROUND
  Cardiac resynchronization therapy (CRT) and atrial ablation procedures currently lack a noninvasive imaging modality for reliable treatment planning and monitoring. Electromechanical wave imaging (EWI) is an ultrasound-based method that has previously been shown to be capable of noninvasively and transmurally mapping the activation sequence of the heart in animal studies by estimating and imaging the electromechanical wave, that is, the transient strains occurring in response to the electrical activation, at both high temporal and spatial resolutions.
  
  
  OBJECTIVE
  To demonstrate the feasibility of transthoracic EWI for mapping the activation sequence during different cardiac rhythms in humans.
  
  
  METHODS
  EWI was perfor`med in patients undergoing CRT and a left bundle branch block (LBBB) during sinus rhythm, left ventricular pacing, and right ventricular pacing, as well as in patients with atrial flutter (AFL) before intervention, EWI findings from patients with AFL were subsequently correlated with results from invasive intracardiac electrical mapping studies during intervention. In addition, the feasibility of single-heartbeat EWI at 2000 frames/s is demonstrated in humans for the first time in a patient with both AFL and right bundle branch block (RBBB).
  
  
  RESULTS
  The electromechanical activation maps demonstrated the capability of EWI to localize the pacing sites and characterize the bundle branch block activation sequence transmurally in patients with CRT. In patients with AFL, the EWI propagation patterns obtained with EWI were in excellent agreement with those obtained from invasive intracardiac mapping studies.
  
  
  CONCLUSIONS
  Our findings demonstrate the potential capability of EWI to aid in the assessment and follow-up of patients undergoing CRT pacing therapy and atrial ablation, with preliminary validation in vivo.
authors: Department of Biomedical Engineering, Columbia University, New York, New York 10027, USA.
authors: Jean
authors: J
authors: Provost
authors: Alok
authors: A
authors: Gambhir
authors: John
authors: J
authors: Vest
authors: Hasan
authors: H
authors: Garan
authors: Elisa E
authors: EE
authors: Konofagou
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging; D018780:Body Surface Potential Mapping / Q000379:methods; D002037:Bundle-Branch Block / Q000000981:diagnostic imaging; D058406:Cardiac Resynchronization Therapy; D017115:Catheter Ablation; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005240:Feasibility Studies; D006325:Heart Atria / Q000000981:diagnostic imaging*; D006329:Heart Conduction System / Q000000981:diagnostic imaging / Q000503:physiopathology; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D014463:Ultrasonography; D055815:Young Adult