Evaluation of Left Ventricular Diastolic Function by Global Strain Rate Imaging in Patients with Obstructive Hypertrophic Cardiomyopathy: A Simultaneous Speckle Tracking Echocardiography and Cardiac Catheterization Study

Abstract

Impaired left ventricular (LV) diastolic function is a common pathophysiological feature of patients with hypertrophic cardiomyopathy (HCM). The noninvasive evaluation of diastolic function in these patients remains a challenge. Speckle tracking echocardiography (STE) provides direct information on intrinsic myocardial function and may improve the diagnostic of diastolic dysfunction in HCM patients. We retrospectively analyzed 51 patients with obstructive HCM (HOCM). Strain rate (SR) curves were obtained for 18 different segments of the LV myocardium. The peak SR during the isovolumic relaxation period (SRIVR ) and the peak early diastolic strain rate (SRE ) were measured for each segment. Cardiac catheterization was performed within 24hours after echocardiographic analysis. LV end-diastolic pressure (LVEDP) was measured and time constant of myocardial relaxation (τ) was calculated. We therefore correlated STE-derived with invasive indices and compared it with flow and tissue Doppler measurements. SRIVR and SRE were significantly reduced in all 51 HOCM patients (0.16±0.09%/sec and 0.71±0.25%/sec).The ratio of peak early mitral inflow velocities to SRIVR and SRE (E/SRIVR and E/SRE ) correlated well with LVEDP (r=0.760, P<0.001; r=0.401, P=0.004). Receiver operating characteristic analysis shown E/SRE ratio had the largest under curve area in predicting HOCM patients with seriously elevated LVEDP. In addition, SRIVR and SRE significantly related with τ (r=-0.611, P<0.001; r=-0.369, P=0.008). Diastolic function was seriously impaired in HOCM patients. The E/SRE ratio can be used to predict LVEDP with acceptable accurate in HOCM patients. In addition, SRIVR is a reliable parameter to assess LV relaxation in patients with HOCM.