title: Echocardiographic evaluation of cardiac resynchronization therapy: ready for routine clinical use? A critical appraisal.
abstract: Cardiac resynchronization therapy (CRT) has been proposed as an alternative treatment in patients with severe, drug-refractory heart failure. The clinical results are promising, and improvement in symptoms, exercise capacity, and systolic left ventricular (LV) function have been demonstrated after CRT, accompanied by a reduction in hospitalization and a superior survival as compared with optimized medical therapy alone. However, 20% to 30% of patients do not respond to CRT. Currently, patients are selected mainly on electrocardiogram criteria (wide QRS complex, left bundle branch block configuration). In view of the 20% to 30% of nonresponders, additional selection criteria are needed. Echocardiography (and, in particular, tissue Doppler imaging) may allow further identification of potential responders to CRT, based on assessment of inter- and intraventricular dyssynchrony. In addition, echocardiography may allow optimal LV lead positioning and follow-up after CRT. In the current review, the different echocardiographic approaches to predict response to CRT are discussed. In addition, the use of echocardiography to guide LV lead positioning and follow-up after CRT are addressed.
authors.affiliation: Leiden University Medical Center, Leiden, The Netherlands. jbax@knoware.nl
authors.forename: Jeroen J
authors.initials: JJ
authors.lastname: Bax
authors.forename: Gerardo
authors.initials: G
authors.lastname: Ansalone
authors.forename: Ole A
authors.initials: OA
authors.lastname: Breithardt
authors.forename: Genevieve
authors.initials: G
authors.lastname: Derumeaux
authors.forename: Christophe
authors.initials: C
authors.lastname: Leclercq
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Schalij
authors.forename: Peter
authors.initials: P
authors.lastname: Sogaard
authors.forename: Martin
authors.initials: M
authors.lastname: St  John Sutton
authors.forename: Petros
authors.initials: P
authors.lastname: Nihoyannopoulos
mesh_terms: D002986:Clinical Trials as Topic; D003955:Diagnostic Tests, Routine; D004452:Echocardiography / Q000379:methods*; D006329:Heart Conduction System / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D009200:Myocardial Contraction / Q000502:physiology; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology