Association of Iodine-123 BMIPP and MIBG Cardiac Uptakes with Left Ventricular Functional Parameters Assessed by Gated Myocardial Perfusion SPECT

We investigated how the degree of cardiac uptakes of radioactive fatty acid (FA) analog ( 123 I-BMIPP) or norepinephrine (NE) analog ( 123 I-MIBG) was related to left ventricular (LV) functional parameters in patients with heart disease, which might be a predictor of cardiac events. Patients with ejection fraction (EF) of 16.2%-82.2% underwent 123 I-BMIPP or 123 I-MIBG myocardial scintigraphy, and were followed up over 1177±486 days. LV systolic functional parameter EF, diastolic parameters 1/3FR (first third filling rate), PFR (peak filling rate), and TPF (time to PFR) were calculated using quantitative gated SPECT. 123 I-BMIPP uptake (n=30) was significantly correlated with EF, 1/3FR, and PFR but not TPF. 123 I-MIBG uptake (n=37) was also correlated with EF, 1/3FR, and PFR but not TPF. In contrast, TPF was positively correlated with age, and was significantly longer in women than in men. Such findings were also observed in normal EF patients (≥50%, n=100). Kaplan–Meier analysis showed the occurrence of earlier cardiac events in the case of patients with decreased 123 I-BMIPP and 123 I-MIBG uptake, decreased PFR, and prolonged TPF. The degree of decreased cardiac uptakes of FA and NE may be associated with the grade of systolic and diastolic dysfunctions assessed by EF, PFR, and 1/3FR. In contrast, prolonged TPF, another diastolic parameter, may rather be caused by aging and female gender, independent of EF. Despite these differences, myocardial FA metabolism impairment, cardiac sympathetic nerve inactivity, decreased PFR, and prolonged TPF may all indicate poor cardiac prognosis in patients with heart disease. Keywords123 I-BMIPP; 123 I-MIBG; Cardiac Function; Heart Failure