Abstract 18908: Incremental Value of Inefficient Deformation Indices for Predicting Response to Cardiac Resynchronization Therapy

Abstract

Background: Previous studies have identified 4 clinical characteristics associated with a favorable response to cardiac resynchronization therapy (CRT): female, left bundle-branch block (LBBB), QRS duration ≥ 150 ms and non-ischemic etiology. This study evaluated the incremental value of baseline inefficient-deformation and time-delay indices over clinical characteristics for predicting CRT response.

Methods: Speckle-tracking longitudinal strain was analyzed in 119 CRT candidates. Patients were divided into subgroups according to sex (male vs female), QRS morphology (LBBB vs non-LBBB), QRS duration (≥ 150 ms vs <150 ms) and heart failure etiology (ischemic vs nonischemic). Inefficient deformation was indexed by the septal systolic stretching that occurred after shortening (SRSsept) and the absolute differences between peak strain and end-systolic strain across 16 segments (SDI). Time to peak strain was measured to derive the septal to lateral delay and the 12-segment standard deviation of time to peak strain. CRT response was defined as a 6-month end-systolic volume reduction ≥ 15%.

Results: Patients with 1 of the 4 favorable characteristics were more likely to exhibit other favorable characteristics and had greater amounts of inefficient deformation than those without. In contrast, time-delay indices were not significantly different in any pairwise comparison except for that between LBBB and non-LBBB patients. Of the 38 patients for whom 6-month follow-up data was available, CRT response was found in 22 (58%). SRSsept and SDI rather than time-delay indices provided significant incremental value over clinical characteristics when predicting CRT response.

Conclusions: Combined SRSsept (or SDI) and favorable characteristics may help identify CRT responders.