[Myocardial ischemia and abnormality of cardiac sympathetic nervous function in apical hypertrophic cardiomyopathy].

Exercise 201Tl myocardial scintigraphy of patients with apical hypertrophic cardiomyopathy (AH) often shows transient perfusion defect in the apex. Catecholamine may be related to the pathogenesis of AH, but this is not certain. The relationship between hypertrophy, myocardial ischemia, and cardiac sympathetic nervous function were investigated by comparing 123I-MIBG myocardial SPECT with exercise 201Tl myocardial SPECT especially at the apex which is the hypertrophic region. Seventeen patients with AH, mean age of 53 +/- 11 years old, underwent 123I-MIBG myocardial SPECT and exercise 201Tl myocardial SPECT on separate days. Decreased tracer uptake regions and the severity and extent of the defect were evaluated visually and compared. Myocardial clearance of 123I-MIBG in apical, midventricular, and basal regions was calculated from the bull's eye display. 123I-MIBG SPECT showed a decreased uptake or defect in the apex of all patients. 201Tl SPECT showed a reversible perfusion defect in the apex of 10 patients, an irreversible perfusion defect in the apex in 3, and normal perfusion in 4. Comparing decreased uptake on the exercise 201Tl myocardial image and 123I-MIBG 4-hour delayed image, the severity of the defect was: MIBG > Tl in 12 patients (71%), MIBG = Tl in 5 (29%), and the extent of the defect was: MIBG > Tl in 11 (65%), MIBG = Tl in 6 (35%). Mean clearance of 123I-MIBG in the apical and midventricular regions was significantly higher than that in the basal region (apical 46.2 +/- 7.1%, midventricular 44.4 +/- 7.8%, basal 38.7 +/- 7.7%).(ABSTRACT TRUNCATED AT 250 WORDS)