Longitudinal two-dimensional strain rate imaging: a potential approach to predict the response to cardiac resynchronization therapy.

The purpose of our study was to test the usefulness of speckle-tracking two-dimensional echocardiography (in particular longitudinal strain and strain rate) in predicting the response to cardiac resynchronization therapy. The standard approach has been tissue Doppler-based echocardiographic imaging (TDI) has initially showed promising results in small clinical trials. However, recent larger, prospective randomized clinical trials (PROSPECT, ReTHINK) showed that TDI is inadequate to predict response from CRT in patients with heart failure. Altogether, these data suggest the need to identify alternative echocardiographic parameters to predict the response to CRT. We included 53 patients suffering from heart failure, who received CRT. TDI and two-dimensional speckle tracking imaging in addition to standard echocardiography were performed prior to CRT. The standard deviation of time to peak longitudinal strain in 12 LV segments (Tstrain-SD) and the standard deviation of time to the end of longitudinal systolic strain rate in six basal LV segments (Tsr-SD) were calculated. Standard echocardiography was performed 6 months after CRT. Patients were classified as echocardiographic responders if the LV end-systolic volume was reduced >15% compared with baseline volumes. No significant difference was seen in baseline Ts-SD, and Tstrain-SD between non-responders and responders. However, the Tsr-SD was much higher in responders than non-responders (95.9 +/- 33.0% vs. 64.8 +/- 39.6%, P < 0.05), and it showed a sensitivity of 73% and specificity of 65% for the defined echocardiographic response using a cutoff value of 70.7 ms. Our study demonstrates that longitudinal two-dimensional strain rate imaging is a promising potential echocardiographic parameter to predict benefit from CRT in patients with heart failure. This hypothesis needs to be further tested in prospective randomized clinical trials.