Assessment of left ventricular systolic dyssynchrony in hypertrophic cardiomyopathy by three-dimensional speckle tracking echocardiography

Abstract

Objective To explore the value of three-dimensional speckle tracking imaging (3D-STI) in evaluating the systolic dyssynchrony of left ventricle(LV) in patients with hypertrophic cardiomyopathy (HCM).Methods A total of 93 consecutive patients with HCM were enrolled,in which 63 patients were non-obstructive HCM (HNCM),30 patients were obstructive HCM(HOCM).In addition,72 healthy subjects were recruited as a control group.An ultrasound system iE33(Philips Medical Systems) was used to acquire and analyze two-dimensional images.Full-volume three-dimensional dynamic images were performed using matrix transducer X5-1.The 16 segments of the time to peak area strain(TAS),the time to peak circumferential strain(TCS),the time to peak longitudinal strain(TLS),the time to peak radial strain(TRS)were analysis using off-line TomTec software (4D LV-Analysis 3.0).Then the standard deviation for the TAS,TCS,TLS,TRS (TAS-SD,TCS-SD,TLS-SD,TRS-SD),the maximal difference value of any of two segments of TAS,TCS,TLS,TRS (TAS-diff,TCS-diff,TLS-diff,TRS-diff),and the indices after standardization(TAS-SD％,TCS-SD％,TLS-SD％,TRS-SD％,TAS-diff％,TCS-diff％,TLS-diff％,TRS-diff％) were calculated,the difference of all these dyssynchroy indices among three groups were compared.Results Compared with the control group,LV end-diastolic,volumes and stroke volume significantly decreased,LV mass and LV diastolic wall thickness significantly increased(P ＜0.05).However,there was no significant difference between LVEF (P ＞0.05).The comparison of the 3D-STI dyssynchrony indices were as followed:compared with the control group,TAS-SD％,TLS-SD％,TRS-SD％,TAS-diff％,TRS-diff％,TLS-diff％ were significantly prolonged in HCM,there were significantly difference(P ＜0.05),while there were no statistics difference in TCS-SD％,TCS-diff％.Compared with the HNCM,TAS-SD％,TCS-SD％,TRS-SD％,TAS-diff％,TRS-diff％,TCS-diff％ were significantly prolonged in HOCM,while there was no statistics difference in TLS-SD％,TLS-diff％.A positive linear correlation exists between left ventricular outflow tract pressure gradient(LVOT-PG) and these dyssynchrony indices.Conclusions The systolic dyssynchrony of the LV are commonly existed in patients with HCM,indicated the impairment of myocardial contractility exists at the early stage of the HCM,3D-STI provided a new method for evaluating LV systolic abnormal in patients with HCM. Key words: Echocardiography; Cardiomyopathy, hypertrophic; Ventricular function, left; Three-dimensional speckle tracking imaging