Potential Application of Tissue Doppler Imaging to Assess Regional Left Ventricular Diastolic Function in Patients with Hypertrophic Cardiomyopathy: Comparison with ¹²³I-β-Methyl Iodophenyl Pentadecanoic Acid Myocardial Scintigraphy

Background: Tissue Doppler imaging (TDI) has been utilized to evaluate left ventricular myocardial dysfunction in patients with hypertrophic cardiomyopathy (HCM); however, no clear explanation for the abnormality of TDI variables has been forthcoming. Hypothesis: Peak negative myocardial velocity gradient (MVG) derived from TDI may correlate with a disorder of fatty acid metabolism in patients with HCM. Methods: Tissue Doppler imaging and ¹²³I-β-methyl iodophenyl pentadecanoic acid ( ¹²³I-BMIPP) myocardial scintigraphy were performed in 15 patients with asymmetric septal hypertrophy (mean age 47 ± 18 years) and in 12 healthy controls (mean age 43 ± 10 years). Results: In early ¹²³I-BMIPP images, accumulation defects were observed in the ventricular septumin 12 patients and in the posterior wall in 8 patients with HCM. Peak negative MVG in the ventricular septum (1.1 ± 0.5 vs. 2.8 ± 0.5, p<0.0001) and posterior wall (5.2 ± 1.4 vs. 6.7 ± 0,8, p< 0.01) was significantly lower in the HCM group than in the controls; also, these parameters were significantly lower in patients with than in those without a defect in the region in question. The peak negative MVG in the ventricular septum and posterior wall correlated inversely with the washout rate in all subjects. Conclusions: Peak negative MVG according to TDI is related to disorder of fatty acid metabolism in the regional left ventricular myocardium of patients with HCM.