Contractile Reserve Assessed by Three-Dimensional Global Circumferential Strain as a Predictor of Cardiovascular Events in Patients with Idiopathic Dilated Cardiomyopathy

Abstract

It has been suggested that the assessment of left ventricular contractile reserve during dobutamine infusion can improve prognostic evaluation for patients with idiopathic dilated cardiomyopathy (DCM). However, the assessment of contractile reserve is often subjective, while three-dimensional (3D) speckle-tracking can quantify three different components of strain simultaneously from all 16 left ventricular segments. The purpose of this study was to investigate the capability of multidirectional deformational indices assessed by 3D speckle-tracking strain to predict cardiac events in patients with DCM. Whether such assessment under dobutamine infusion can enhance this method's predictive capability was also evaluated by comparison with two-dimensional (2D) speckle-tracking. Sixty-five patients with DCM with a mean ejection fraction of 34 ± 8% (all <45%) were prospectively recruited, and both 3D and 2D speckle-tracking echocardiography was used to measure global circumferential strain (GCS), radial strain, and longitudinal strain at baseline and during dobutamine infusion (20 μg/kg/min). Event-free survival was then tracked over 12 months. Among all indices of contractile reserve, increase in 3D GCS under dobutamine infusion ≤ 2.71% best predicted cardiovascular events, with 83% sensitivity, 80% specificity, and an area under the curve of 0.874 (P < .001). Furthermore, the area under the curve for increase in 3D GCS was significantly larger than that for both resting 3D GCS and increase in 2D GCS (P < .05 for both). On multivariate Cox analysis, increase in 3D GCS was the only independent predictor of cardiovascular events (hazard ratio, 0.635; P< .001). Assessment of contractile reserve using 3D GCS has the potential to predict cardiovascular events in patients with DCM and may thus have clinical implications for the management of such patients.