Keisuke Kiso MD, Presenter: Nothing to Disclose

Yoshio Ishida MD, Abstract Co-Author: Nothing to Disclose

Kazuki Fukuchi MD, Abstract Co-Author: Nothing to Disclose

Mechanisms underlying LV functional deterioration in hypertrophic cardiomyopathy (HCM) are not well elucidated. So,we investigated the relationship between the LV remodeling of HCM and the perfusion or the fatty acid metabolism of myocardium.

We performed the follow-up study of HCM patients by echocardiography, perfusion imaging with thallium-201 (Tl) and fatty acid imaging with I-123 BMIPP (BMIPP). Twenty-five patients with HCM (M:F=18:7, 54±15 years) were enrolled for this study. The mean follow-up periods were 2.5±2.0 years. The subjects were divided into two groups based on the progression of LV cavity dilatation during the follow-up, 8 with (Gp A) and 17 without (Gp B) an increase in LV end-diastolic volume, estimated by echocardiography, more than 20%. Regional myocardial distributions in Tl and BMIPP were evaluated using SPECT : the myocardium was divided into 20 segments and the degree of reduced tracer uptake in each segment was scored using a four-point scoring system (defect score, DS 3:severely reduced, DS 2:moderately reduced, DS 1:mildly reduced, DS 0:normal). The sum of the DSs (SDS) in all segments and the difference in BMIPP and Tl SDSs (d-SDS) as an index of myocardial perfusion-metabolism mismatch were calculated. Also, from anterior planar 20-min early BMIPP imaging, heart/mediastinum count ratio (H/M) was determined.

There was no difference in age, the degree of hypertrophy and the incidence of HOCM between Gps A and B. However, Gp A had higher BMIPP SDS and d-SDS (p=0.003 and 0.006, respectively), and lower H/M (p=0.04) than Gp B in the initial study. From the initial to second study, Tl SDS significantly increased in Gp A but remained the same in Gp B, while BMIPP SDS tended to decrease in Gp A but remained the same in Gp B. The change in Tl SDS positively correlated with that in LVEDV in all patients.

In conclusion, the impaired myocardial fatty acid metabolism and consequent tissue damage may relate to LV remodeling in non-familial HCM patients. The observation of myocardial perfusion and metabolism mismatch by Tl and BMIPP SPECT images is helpful for prediction of the LV remodeling in this disease.

Kiso, K, Ishida, Y, Fukuchi, K, Impaired Myocardial Fatty Acid Metabolism may Relate to LV Remodeling in Hypertrophic Cardiomyopathy: Estimation by I-123 BMIPP SPECT.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4407647.html