The Speckle Tracking Imaging for the Assessment of Cardiac Resynchronization Therapy (START) study.

BACKGROUND

We sought to identify the feasibility of speckle tracking echocardiography (STE) to predict cardiac resynchronization therapy (CRT) responders in a prospective multicenter study. METHODS AND RESULTS: Patients who were newly implanted with a CRT device were enrolled. Time (T) from QRS to maximum peak radial and circumferential strain (CS) in 6 segments on the left ventricular (LV) short-axis plane, and to the maximum peak of longitudinal strain in 18 segments on 3 apical LV planes was measured (Tmax). In segments with multiple peaks on the time-strain curves, time to the first peak (Tfirst) was also assessed. Difference in T between the earliest and latest segment and standard deviation (SD) of T in each strain component were assessed. CRT responders were defined as having LV end-systolic volume reduction >15% at 6 months after CRT. Clinical outcomes were assessed with a composite endpoint of death from cardiac causes or unplanned hospitalization for heart failure. Among 180 patients, 109 patients were identified as responders. Tfirst-SD of CS >116 ms was selected as the best independent predictor of CRT responders (P<0.001, hazard ratio=9.83, 95% confidence interval 3.78-25.6). In addition, Tfirst-SD of CS was associated with the clinical endpoints.

CONCLUSIONS

This prospective multicenter study revealed the high feasibility of dyssynchrony assessment by STE, which may improve the ability to predict CRT responders.