![]() ![]() However, time to peak contraction alone was not sufficient to determine patients’ response to CRT, and time to onset of contraction can actually affect patients’ responsiveness to CRT as well. Of note, both studies mainly adopted dyssynchrony indexes of time to peak systolic velocities by Tissue Doppler Imaging (TDI). Nevertheless, the results of the PROSPECT (Predictors of Response to CRT) trials and the Echo-CRT (Echocardiography Guided Cardiac Resynchronization Therapy) trials make echocardiography dyssynchrony index a controversial tool in selecting patients for CRT. Observational studies suggested that mechanical rather than electrical dyssynchrony can predict the CRT outcome. However, more than 30% of patients do not benefit, and some may even experience worsening from CRT. Current guidelines recommend LBBB with QRS duration of ≥150 ms by electrocardiography (ECG) for CRT. Randomized controlled trials have demonstrated that cardiac resynchronization therapy (CRT) is an effective therapy for patients suffering from heart failure refractory to medical therapy with widened electrocardiographic QRS complexes and reduced ejection fraction (EF). When analyzing myocardial strain by STE, contraction during LVEj should be highlighted. ![]() STE can evaluate left ventricular contraction efficiency and contractility to predict CRT response. Patients with poorer myocardial contraction efficiency and better contractility are more likely to benefit from CRT. ResultsĪccording to LV end systolic volume (LVESV) and LV eject fraction(LVEF) values at 6-month follow-up, subjects were classified into responder and non-responder groups, ECR (OR 0.87, 95%CI 0.78–0.97, P < 0.05) and maximum longitudinal strain (MLS) (OR 2.22, 95%CI 1.36–3.61, P < 0.01) were the two independent predictors for CRT response, Both TTO-16SD and TTP-16SD failed to predict outcome. 16-segement Standard deviation of time to onset strain (TTO-16SD) and time to peak strain (TTP-16SD) were included as the dyssynchrony indexes. Primary outcome events were predefined as death or HF hospitalization, and secondary outcome events were defined as all-cause death during the follow-up. Our prospective pilot study including 70 CRT candidates, parameters of myocardial contraction timing and contractility were measured by speckle tracking echocardiography (STE) and efficiency indexes were calculated accordingly at baseline and at 6-month follow-up. This study prospectively investigated whether efficiency indexes could predict CRT outcome. Myocardial Contraction Efficiency was defined as the ratio of Efficient Contraction Time (ECTR) and amplitude of efficient contraction (ECR) during LVEj against that in the entire cardiac cycle. In patients with left ventricular (LV) dysssynchrony, contraction that doesn’t fall into ejection period (LVEj) results in a waste of energy due to inappropriate contraction timing, which was now widely treated by cardiac resynchronization therapy(CRT). ![]()
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