First, we studied the diagnostic utility of myocardial imaging with 123I-BMIPP (
BMIPP), a 3-methyl-branched
fatty acid analog, in patients with various types of
cardiomyopathy and
left ventricular dysfunction (ejection fraction below 40%) by comparing with myocardial flow tracer imaging. The incidence of a dissociation between myocardial
BMIPP and 201Tl distributions (
BMIPP < 201Tl) as a marker of metabolic abnormality in viable tissue varied considerably among various
heart diseases. Patients with ischemic
cardiomyopathy and the dilated form of
hypertrophic cardiomyopathy had a higher incidence while those with idiopathic dilated, alcoholic and hypertensive
cardiomyopathy had a lower incidence. These results suggest that the marked difference between ischemic and
idiopathic dilated cardiomyopathies may contribute to the differential diagnosis between these two diseases which are main basic abnormalities in
congestive heart failure. Second, we investigated the relationship between myocardial
BMIPP uptake and ventricular stress in patients with right ventricular pressure overload due to
pulmonary hypertension. Myocardial
BMIPP uptake in the right ventricle estimated by referring to uptake in the left ventricle showed a significant correlation with mean pulmonary artery pressure (mPAP) and no significant difference with myocardial
99mTc-sestamibi uptake in the 15-81 mmHg mPAP range. These results suggest that myocardial utilization of
free fatty acid may be preserved in the presence of higher ventricular wall stress.