Predicting CRT Response with Speckle Tracking Echocardiography: A Systematic Review and Meta-analysis.

Abstract

Nearly 30% of patients with cardiac resynchronization therapy (CRT) are non- responders. Speckle tracking echocardiography (STE) parameters are able to evaluate electromechanical dyssynchrony that could improve outcomes. We aim to examine the association between various STE parameters with CRT response and clinical outcomes in heart failure patients. Searching was done on three medical databases. STE parameters assessed are dyssynchrony index (time delay of peak strain between walls > 130ms), myocardial work indices (global constructive and wasted work - GCC and GWW, etc) and strain patterns. Meta- analysis with random effect model was used to pool the effect sizes. Fifty-one observational studies comprising of 11491 patients ranging from 63 - 71 years old were included. Dyssynchrony index with radial strain is not associated with CRT response but with risk reduction of clinical outcome (HR 0.51, CI: 0.39 - 0.67). This association is also found in unfavorable ECG (HR 0.77), and non-LBBB (HR 0.47) populations. Meta-regression result did not show the association of LBBB, ischemic heart disease and QRS duration as covariates to the outcomes. GWW is associated with an increased odds of CRT response (OR 4.78) and risk reduction of clinical outcomes (HR 0.44). Deformation strain pattern 1/2 and typical LBBB strain are associated with increased odds of CRT response (OR 8.26 and 5.07) while deformation pattern 3 and absence of typical LBBB strain pattern with increased risk of clinical outcome (HR 3.22 and 2.77). Various STE parameters could be used to improve CRT response and clinical outcome in heart failure patients.