Cor Vasa 2016, 58(3):e340-e351 | DOI: 10.1016/j.crvasa.2015.08.001

Echocardiography and cardiac resynchronization therapy

Josef Marek^*, Jana Gandalovičová, Eva Kejřová, Miroslav Pšenička, Aleš Linhart, Tomáš Paleček

II. interní klinika kardiologie a angiologie, 1. lékařská fakulta Univerzity Karlovy a Všeobecná fakultní nemocnice, Praha, Česká republika

Cardiac resynchronization therapy (CRT) is an effective therapeutic option in patients with congestive heart failure, left ventricular ejection fraction ≤ 35%, and a widened QRS complex. However, a significant proportion of individuals do not respond to CRT favorably. Understandably, a large number of studies have addressed various techniques to improve patient selection for CRT and to improve responder rate in patients with CRT devices. A large proportion of these approaches utilize echocardiography.
Techniques for improved patient selection include various metrics of dyssynchrony associated with response to CRT and long-term outcome. Partly because of failure in PROSPECT trial, these techniques have so far not been successfully translated into clinical practice.
Novel echocardiographic approaches aiming to improve responder rate are based on selecting optimal placement for left ventricular lead, using speckle-tracking echocardiography to avoid scarred tissue and to guide the LV lead placement towards late-contracting segments. Single center randomized trials have shown positive results, but these need to be validated in multicenter studies.
Furthermore, several echocardiographic techniques have been developed for individual optimization of atrioventricular and interventricular delay settings, based on left ventricular filling patterns, cardiac output, and dyssynchrony. Again, despite encouraging single center studies, data from multicenter trials are so far lacking or inconclusive.
While mixed results of studies using current echocardiographic techniques cannot warrant their routine clinical use, proper selection of patients for CRT and improving responder rate remains an important goal. Echocardiographic methods are continually evolving to address these issues. However, a meticulous approach including multicenter validation is needed to ensure clinical applicability in future.

Keywords: Bundle branch block; Cardiac resynchronization therapy; Echocardiography; Heart failure

Received: July 13, 2015; Accepted: August 2, 2015; Published: June 1, 2016  Show citation