Left ventricular discoordination index measured by speckle tracking strain rate imaging predicts reverse remodelling and survival after cardiac resynchronization therapy

Abstract

AimsThis study aimed to evaluate the predictive value of a baseline speckle tracking strain rate imaging-derived discoordination index for response to cardiac resynchronization therapy (CRT). Methods and resultsNinety-seven patients with QRS ≥120 ms and left ventricular (LV) ejection fraction ≤35% were prospectively followed after CRT in the Mayo CRT Registry. The LV discoordination index (stretch/shortening or thinning/thickening during ejection) was calculated from three types of deformation, radial, circumferential, and longitudinal, using twodimensional speckle tracking strain rate imaging. The benefit of CRT was evaluated by reverse remodelling (i.e. reduction of LV end-systolic volume ≥15% at 6-month follow-up) and survival. The optimal cut-off value of the baseline discoordination index in discriminating responders from non-responders was determined by receiver operating characteristic curve analysis. Significant differences in baseline indices between responders and non-responders were noted for radial and circumferential discoordination indices. A mid-ventricular radial discoordination index (RDI-M) .38% best predicted responders, especially in patients with ischaemic cardiomyopathy (area under the curve 0.86 for all patients, sensitivity 80%, and specificity 91%). Death occurred in 28 patients over a median follow-up of 3.2 years. When adjusted for confounding variables, lack of significant discoordination (RDI-M ,38%) before CRT was associated with a particularly high mortality (hazard ratio 7.05, 95% confidence interval 2.45 -26.0). ConclusionLV discoordination assessed by speckle tracking RDI-M imaging was able to predict reverse remodelling at 6 months and survival of patients who received CRT.--

Mechanisms of Right Ventricular Electromechanical Dyssynchrony and Mechanical Inefficiency in Children After Repair of Tetralogy of Fallot

“…18 Similar LV mechanical inefficiency between contracting and stretched segments has been quantified as the mechanical discoordination index and as contraction-stretch discoordination, which predict CRT response. 19,20 How applicable this will be to the failing RV in the setting of RBBB remains to be studied, although hemodynamics of the failing RV can be acutely improved in rTOF with RBBB using pacing. …”

Peripheral endothelial function may predict the effectiveness of beta-blocker therapy in patients with idiopathic dilated cardiomyopathy

“…According to previous studies, successful LVRR was defined as >15% reduction in LVESV in addition to >10% improvement in LV sytolic functional recovery [22,23]. Accordingly, LVRR was observed in 40% of all patients (21/52) and 75% of the responders (21/28).…”

Mechanistic Evaluation of Echocardiographic Dyssynchrony Indices

“…3,4,31 In a recent study with a patient population comparable to ours, Miyazaki et al 4 showed that conventional Doppler-derived indices assessing timing of valve opening and closure outclassed more complicated dyssynchrony indices, partly due to their low measurement variability. In another study by the same institute, Wang et al 32 found mechanical discoordination rather than dyssynchrony to be predictive for CRT response at 6-month follow-up and for long-term survival. The latter 2 studies are in close agreement with our finding that SRSsept and IVMD, being direct and indirect indices of mechanical discoordination, respectively, better predict CRT response than time-to-peak indices of mechanical dyssynchrony such as Strain-SL and SPWMD.…”