title: Three-dimensional propagation imaging of left ventricular activation by speckle-tracking echocardiography to predict responses to cardiac resynchronization therapy.
abstract: BACKGROUND
  On the basis of the electromechanical coupling theory, an activation imaging system has been developed with three-dimensional speckle-tracking echocardiography. The aim of this study was to determine the association between left ventricular (LV) propagation patterns by activation imaging and response to cardiac resynchronization therapy (CRT).
  
  
  METHODS
  This was a retrospective, single-center study. Eighty-one patients undergoing CRT, of whom 50 (61.7%) had left bundle branch block (LBBB), were enrolled. Activation imaging studies were performed with a three-dimensional speckle-tracking echocardiographic system, which allowed visualization of LV activation propagation and measurement of the time from the QRS complex to activation onset. A CRT volume responder was defined as a patient with ≥15% reduction of LV end-systolic volume at 6 months after CRT. Clinical outcomes were assessed with the composite end point of death due to cardiac causes or unplanned hospitalization for cardiac diseases.
  
  
  RESULTS
  In patients with LBBB, the main activation pattern (74%) was a U-shaped propagation pattern, which was characterized as propagation from the midseptum to the lateral or posterior wall through the apex. In patients without LBBB, various non-U-shaped propagation patterns were observed in the majority of patients (97%). Among the 41 CRT responders, almost all (87.8%) had the U-shaped propagation pattern. During follow-up (median, 20 months), 29 patients (35.8%) reached the clinical end points. In a multivariate Cox proportional hazards model, a U-shaped propagation pattern was associated with the end points independently of LBBB or LV end-diastolic volume.
  
  
  CONCLUSIONS
  The U-shaped propagation pattern on three-dimensional speckle-tracking echocardiography was significantly associated with a favorable CRT response. Activation pattern analysis may provide additional information to predict response to CRT.
authors: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan. Electronic address: yo-seo@md.tsukuba.ac.jp.
authors: Yoshihiro
authors: Y
authors: Seo
authors: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
authors: Tomoko
authors: T
authors: Ishizu
authors: Cardiovascular Division, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan.
authors: Ryo
authors: R
authors: Kawamura
authors: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
authors: Masayoshi
authors: M
authors: Yamamoto
authors: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
authors: Kenji
authors: K
authors: Kuroki
authors: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
authors: Miyako
authors: M
authors: Igarashi
authors: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
authors: Yukio
authors: Y
authors: Sekiguchi
authors: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
authors: Akihiko
authors: A
authors: Nogami
authors: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
authors: Kazutaka
authors: K
authors: Aonuma
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: Cardiac resynchronization therapy; Dyssynchrony; Heart failure; Speckle-tracking echocardiography; Three-dimensional echocardiography