Left ventricular 12 segmental strain imaging predicts response to cardiac resynchronization therapy.

Background: The number of non-responders to cardiac resynchronization therapy (CRT) exposes the need for better patient selection criteria for CRT. This study aimed to identify echocardiographic parameters that would predict the response to CRT.
Methods: Forty-five consecutive patients receiving CRT-D implantation for heart failure (HF) were included in this prospective study. New York Heart Association (NYHA) class, 6-minute walk distance, electrograph character, and multi echocardiographic parameters, especially in strain patterns, were measured and compared before and six months after CRT in the responder and non-responder groups. Response to CRT was defined as a decrease in left ventricular endsystolic volume (LVESV) of 15% or more at 6-month follow up.
Results: Twenty-two (48.9%) patients demonstrated a response to CRT at 6-month follow-up. Significant improvement in NYHA class (P < 0.01), left ventricular end-diastolic volume (LVEDV) (P < 0.01), and 6-minute walk distance (P < 0.01) was shown in this group. Although there was an interventricular mechanical delay determined by the difference between left and right ventricular pre-ejection intervals ((42.87 ± 19.64) ms vs. (29.43 ± 18.19) ms, P = 0.02), the standard deviation of time to peak myocardial strain among 12 basal, mid and apical segments (Tε-SD) ((119.97 ± 43.32) ms vs. (86.62 ± 36.86) ms, P = 0.01) and the non-ischemic etiology (P = 0.03) were significantly higher in responders than non-responders, only the Tε-SD (OR = 1.02, 95% CI = 1.01 - 1.04, P = 0.02) proved to be a favorable predictor of CRT response after multivariate Logistic regression analysis.
Conclusion: The left ventricular 12 segmental strain imaging is a promising echocardiographic parameter for predicting CRT response.