Impairment of myocardial fatty acid metabolism in patients with hypertrophic cardiomyopathy

123I-(BMIPP) and 201Tl myocardial scintigraphies were performed in 30 patients with hypertrophic cardiomyopathy (HCM). The mean value of 123I-BMIPP uptake was significantly less in the anterior and posterior areas of junction between the ventricular septum (VS) and the free wall (AJ, PJ) and apex. The uptake of 123I-BMIPP was reduced (<80%) in AJ in 18 patients, PJ in 23 and the apex in 26. The uptake of 123I-BMIPP was reduced in these three segments in 14 patients. The uptake of 201Tl was reduced simultaneously in the same three segments in only six patients, who also showed 12'3I-BMIPP reduction. Quantitative dual tracer autoradiography with 125I-BMIPP and 201Tl was carried out in WKY/NCrj rats and normal Wistar rats. In 21 WKY/NCrj rats, the mean value of 125I-BMIPP uptake was significantly less in AJ and PJ than in the other segments. The uptake of 125I-BMIPP was reduced (<0.80) in AJ in 12 rats and PJ in 13. In 12 Wistar rats, there were no significant differences in the mean value of 125I-BMIPP uptake in the left ventricle. The 201Tl uptake was homogeneous in the left ventricle of both the WKY/NCrj rats and Wistar rats. In the WKY/NCrj rats, the grade of myocardial disarrangement was higher in AJ, PJ and VS than in the other segments. In the Wistar rats, there were no significant differences in the grade of myocardial disarrangement among the segments. Disruption of the cristae in the mitochondria was observed only in the junctional area of WKY/NCrj rats. In the WKY/NCrj rats, the activity of succinate dehydrogenase was lower in AJ, PJ and VS than in the other segments. The disorder of myocardial fatty acid metabolism was most marked in AJ, PJ and the apex of the hearts with HCM. It is suggested that the impairment of the myocardial fatty acid metabolism is closely related to an abnormal myocardial architecture, and that it may be due to depressed mitochondrial function. (J.P.N.). 59 refs