Abstract 2157: Quantitative Contrast Echocardiography for the Differentiation between Hypertensive Heart Disease, Hypertrophic Cardiomyopathy, Athlete’s Heart and the Normal Myocardium
Background: We have previously shown that relative blood volume (rBV), i.e. capillary density, is reduced in patients with hypertensive heart disease (HHD) compared to sedentary individuals (S) and athlete’s heart (AH). We sought to assess whether hypertrophic cardiomyopathy (HCM) may be distinguished from these forms of left ventricular hypertrophy (LVH) in vivo by quantitative contrast echocardiography.
Methods and Results: We examined 15 individuals, matched for age (average 33yrs) and gender, in each of the four groups: HCM, HHD, AH and S. rBV (ml/ml), its exchange frequency β (1/min) and MBF at rest and during adenosine-induced hyperemia were derived from myocardial contrast echocardiography in mid septal regions. The ratio of MBF during hyperemia and MBF at rest yielded myocardial blood flow reserve (MBFR). Left ventricular mass index was higher in HCM (148±47g/m2) HHD (140±30g/m2) and AH (134±15g/m2) than in S (94±13g/m2, p<0.01). rBV was not different between HCM (0.084±0.023ml/ml) and HHD (0.097±0.016ml/ml), but lower than in AH (0.151±0.024ml/ml, p<0.01) and S (0.129±0.026ml/ml, p<0.01). Conversely, MBFR was lower in HCM (1.67±0.93) compared to HHD (2.8±0.93, p<0.04), AH (4.74±1.46, p<0.01) and S (3.36±1.03, p<0.01). At rest, an rBV of 0.111ml/ml distinguished between HHD or HCM and S with a sensitivity of 80% and a specificity of 90%, and between HCM and AH with sensitivity of 100% and a specificity of 100%.
Conclusions: Capillary density is reduced in both forms of pathologic LVH, i.e. HCM and HHD, compared to S and AH. rBV accurately differentiated between HCM and AH in vivo.