Speckle tracking echocardiography analyses of myocardial contraction efficiency predict response for cardiac resynchronization therapy

Zibire Fulati,Yu Kang,Yangang Su,Haiyan Chen,Ning Sun,Xianhong Shu,Yang Liu

doi:10.1186/s12947-018-0148-5

Abstract

BackgroundIn 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). 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. This study prospectively investigated whether efficiency indexes could predict CRT outcome.MethodsOur 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. Primary outcome events were predefined as death or HF hospitalization, and secondary outcome events were defined as all-cause death during the follow-up. 16-segement Standard deviation of time to onset strain (TTO-16SD) and time to peak strain (TTP-16SD) were included as the dyssynchrony indexes.ResultsAccording 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. Patients with poorer myocardial contraction efficiency and better contractility are more likely to benefit from CRT.ConclusionsSTE can evaluate left ventricular contraction efficiency and contractility to predict CRT response. When analyzing myocardial strain by STE, contraction during LVEj should be highlighted.

Highlights

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) [1, 2]
Primary outcome events were predefined as death or HF hospitalization, and secondary outcome events were defined as all-cause death during the follow-up
A significantly larger left ventricular (LV) volume was observed in the Non-responder group and a significantly higher the onset of contraction (TTO) dyssynchrony index was seen in the responder group (Table 1 shows the baseline characteristics of the Responder and Non-responder groups)

Summary

Introduction

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) [1, 2]. The results of the PROSPECT (Predictors of Response to CRT) trials and [6] the Echo-CRT (Echocardiography Guided Cardiac Resynchronization Therapy) trials [7] make echocardiography dyssynchrony index a controversial tool in selecting patients for CRT. 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 widely treated by cardiac resynchronization therapy(CRT). This study prospectively investigated whether efficiency indexes could predict CRT outcome

Methods

Results

Conclusion