Abstract 5730: Discrimination of Hypertrophied Myocardium between Hypertrophic Cardiomyopathy and Myocardial Hypertrophy due to Essential Hypertension Using Two-dimensional Strain Analysis
Both hypertrophic cardiomyopathy (HCM) and hypertensive heart disease are characterized as myocardial hypertrophy based on common morphology. It is very important to discriminate these conditions in terms of therapeutic strategy. However, it may be difficult to differentiate HCM from LVH due to essential hypertension (EHT), as HCM often coexists with EHT. Our aim was to elucidate the qualitative difference in myocardial strain in the hypertrophy of HCM and EHT. Patients (N=22) with EHT (mean age, 61+/−13 y) and age- and sex-matched patients (N=35) with HCM (mean age, 62+/−14 y) underwent echocardiography with a Vivid 7 Dimension (GE Healthcare). Radial and circumferential strains were measured with custom software (EchoPacPC : GE Healthcare) with a 2-dimensional speckle method from the parasternal short axis view at the mid ventricular level. LV diastolic dimension (46+/−6 mm vs 47+/−5 mm), systolic dimension (28+/−4 mm vs 30+/−5 mm), ejection fraction (67+/−8% vs 64+/−8%) and mass index (136+/−35 g/m2 vs 137+/−34 g/m2) did not differ between the EHT and HCM groups. Radial strain in the septum was decreased in HCM versus EHT patients (33+/−15% vs 53+/−19%, p<0.01), but did not differ in the free wall. Circumferential strain in the septum was decreased in HCM compared with EHT patients (−21+/−5% vs −24+/−5%, p<0.01), but did not differ in the free wall. The ratio of septum to free wall radial strain (S/F rad) in HCM patients was decreased compared with the EHT group (0.76+/−0.18% vs 1.01+/−0.15%, p<0.001). The ratio of septum to free wall circumferential strain (S/F circ) did not differ between groups Multivariate analysis showed that among age, E/Ea, ratio of septum to posterior wall thickness, LV mass index and S/F rad, S/F rad was the only independent predictor for HCM (beta=0.24, p<0.05). A cutoff of S/F rad <0.90 discriminated between hypertrophy due to EHT and HCM with 90.9% sensitivity and 77.1% specificity. The differences in strain in radial direction between HCM and HT are not due to the degree of myocardial hypertrophy, but to myocardial characteristics. Two-dimensional strain analyses may help discriminate these 2 types of myocardial hypertrophy.