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Objective: Individuals with type 2 diabetes are at high risk for cardiovascular events. We evaluated the prognostic value of gated myocardial perfusion single-photon computed tomography (SPECT) for asymptomatic diabetic patients in a Japanese population.Research Design and Methods: Asymptomatic patients (n=485) aged≥50 years with either a maximal carotid artery intima-media thickness of ≥1.1 mm, or a urinary albumin ≥30 mg/g creatinine or who had at least two of the following, abdominal obesity, low HDL cholesterol, high triglyceride levels, and hypertension, were enrolled at 50 institutions. The patients were evaluated using gated SPECT with the stress-rest protocol and followed up for 3 years.Results: During the follow-up period, 62 (13%) events occurred, including 5 cardiac deaths and 57 cardiovascular events. Patients with summed stress scores (SSS) of ≥9 had a significantly higher incidence (of either death or cardiovascular events) than those with SSS scores of <9 (23 vs. 12%; P=0.009). Multivariate Cox regression analysis showed that significant variables were SSS≥9, a low estimated glomerular filtration rate, and being a current smoker. Univariate Cox regression analysis showed that ticlopidine and insulin use are potent medical modulators of cardiovascular events.Conclusions: The incidences of cardiovascular events and death were significantly high in a select population of type 2 diabetic patients with SPECT abnormalities. A targeted treatment strategy is required for asymptomatic but potentially high-risk patients with type 2 diabetes. [ABSTRACT FROM AUTHOR]

Objective: To determine whether cardiac iodine-123 metaiodobenzylguanidine (123I MIBG) imaging is useful in predicting the prognosis of patients with chronic heart failure. Design: Cardiac (123)I MIBG imaging was done on entry to the study. The cardiac MIBG washout rate was calculated from anterior chest view images obtained 20 and 200 minutes after injection of the isotope. Study patients were divided into two groups with washout rates above and below 27% (the mean value + 2 SD obtained in 20 normal subjects), and were then followed up. Setting: Tertiary referral centre. Patients: 79 patients with chronic heart failure in whom the left ventricular ejection fraction was less than 40%. Results: There were 37 patients in group 1 (washout rate of &ges;27%) and 42 in group 2 (< 27%). During a follow up period of between 1 and 52 months, eight patients died suddenly and five died of worsening heart failure in group 1, while none died in group 2; 13 patients in group 1 and four in group 2 were admitted to hospital for progressive heart failure. Kaplan-Meier analysis showed that group 1 had a significantly higher mortality and morbidity (p = 0.001 and p < 0.001, respectively) than group 2. Conclusions: Cardiac 123I MIBG washout rate seems to be a good predictor of prognosis in patients with chronic heart failure. [ABSTRACT FROM AUTHOR]

Clinical investigations have suggested that the defects in SPECT images of a free fatty acid analog, I-123 beta-methyliodophenyl pentadecanoic acid (BMIPP) may indicate the ischemic risk area. To elucidate whether I-123 BMIPP can indicate the area at risk of ischemia, ex-vivo autoradiography was performed in rats whose left coronary artery was occluded for 60 min and then reperfused. I-123 BMIPP was injected at the acute stage (n = 10), or the subacute stage (7 days after reperfusion; n = 9). Infarction and the area at risk were identified by triphenyl tetrazolium chloride staining and injection of methylene blue during religation just before sacrifice, respectively. The BMIPP uptake in the risk area was significantly lower than that in the remote area at the acute (risk, 53.7+/-23.3% of the uptake at right ventricle, mean +/- SD; remote, 109.3+/-11.8%; p < 0.01) and subacute (risk, 52.5+/-11.5%; remote, 97.9+/-14.3%; p < 0.01) stages. In addition, the area with reduced uptake of I-123 BMIPP showed a significant correlation with the area at risk both at the acute (r = 0.98, p < 0.01) and subacute (r = 0.92, p < 0.01) stages. In conclusion, the area at risk can be evaluated by I-123 BMIPP both at the acute and subacute stages. [ABSTRACT FROM AUTHOR]

To elucidate the change in perfusion and aerobic metabolism in myocarditis, tissue counting and dual tracer ex vivo autoradiography with Tl-201 and a free fatty acid analog, I-123- or I-125-labeled (p-iodophenyl)-methyl-pentadecanoic acid (BMIPP), were performed in rats with myocarditis induced by immunization with cardiac myosin. Inflammatory damage was classified histologically. At the acute stage (2-4 weeks after the antigen-injection), total heart uptakes of Tl and BMIPP and the ratio (BMIPP/Tl) were significantly reduced in myocarditis rats (N = 15) compared with the controls (N = 12). Myocardial distribution of Tl and BMIPP was not homogeneous. Relative uptake of Tl and BMIPP (N = 9, 128 regions) was gradually decreased with the extent of inflammation, and the regional BMIPP/Tl was smaller than the control. At the subacute stage (7 weeks after the antigen-injection), total Tl uptake in myocarditis rats (N = 5) recovered to the control level (N = 4), but that of BMIPP was still significantly lower than the control. BMIPP/Tl was still significantly lower in myocarditis. Myocardial distribution of Tl and BMIPP recovered to be more homogeneous. Relative uptake of Tl and BMIPP (N = 6, 78 regions) still gradually but significantly decreased with the extent of inflammation. Regional BMIPP/Tl was still depressed in myocarditis. These results indicate that myocardial perfusion and aerobic metabolism were discrepant and heterogeneously suppressed with severe inflammation during the acute stages, but the difference decreases with time. Examination with Tl-201 and BMIPP may provide information about the severity of myocarditis. [ABSTRACT FROM AUTHOR]

Patients with left bundle branch block (LBBB) often show abnormal images on exercise thallium (T1)-201 scintigraphy without evidence of significant coronary stenosis. We investigated the mechanism for this phenomenon. Six patients with LBBB and without significant coronary stenosis underwent T1-201 SPECT, ECG-gated SPECT imaging with Tc-99m-methoxyisobutyl-isonitrile (MIBI), and atrial pacing stress test. The % count amplitude in Tc-99m-MIBI images was calculated as [(maximal counts) - (minimal counts)]/(minimal counts) x 100. Though all patients had a low count in the septal and inferior wall in T1-201 SPECT images, there was no ischemic production of lactate during an atrial pacing stress test. Nevertheless, gated SPECT images showed attenuated septal activity during systole. In patients with LBBB, the ratios of % count amplitude at the septum to that at the lateral wall at rest (0.47 +/- 0.05, mean +/- SE) were significantly less than the controls (n = 5, 0.83 +/- 0.12, p = 0.014). In conclusion, these results suggest that abnormal T1-201 SPECT images of the septum in patients with LBBB are partially caused by impaired septal wall thickening during systole. Such an abnormal wall motion may reduce blood flow demands to the septum, resulting in reduction of coronary blood flow with little ischemia. [ABSTRACT FROM AUTHOR]

To elucidate the relation between glucose tolerance and myocardial uptake of F-18 fluorodeoxyglucose (FDG), FDG-PET with 75 g oral glucose loading was performed on 43 coronary artery disease patients (twice in 2 patients). The patients were divided into 4 groups based on the blood glucose level (BS) and the insulinogenic index (II): group 1, normal (n = 9); group 2, impaired glucose tolerance (IGT, n = 12); group 3, mild diabetes mellitus (DM) (II > 0.4, n = 12); and group 4, severe DM (II < or = 0.4, n = 12). Percent (%) dose uptake of FDG in the normal regions of the myocardium was not significantly different in groups 1, 2, and 3, but it was much lower in group 4 than in groups 1 and 2. In groups 2, 3, and 4, % dose uptake showed a definite negative correlation with BS 60 min after glucose loading (r = -0.450, p < 0.05), and a close positive correlation with II (r = 0.363, p < 0.05). These findings indicate that myocardial FDG uptake in normal regions is not greatly impaired in patients with IGT or mild DM. Myocardial viability can be assessed by oral glucose loading in patients with IGT and mild DM as well as in patients with normal glucose tolerance. [ABSTRACT FROM AUTHOR]

It has been reported that beta-blockade has beneficial effects on the cardiac function and prognosis of patients with congestive heart failure. However, the mechanism for these effects remained unclear. This study compared the use of an angiotensin-converting enzyme (ACE) inhibitor (enalapril, 2.5 to 5.0 mg/day, or delapril, 15 to 30 mg/day) alone with the effects of beta-blockade therapy (metoprolol, 40 to 60 mg/day) coupled with an ACE inhibitor on global and regional left ventricular (LV) function in patients with dilated cardiomyopathy. In 12 patients with dilated cardiomyopathy, the global LV ejection fraction (EF), regional EF (rEF), and regional ejection time (rET) were determined by sector analysis of the radionuclide ventriculogram before and after therapy (duration 14 +/- 9 months). The coefficients of variation of rEF and rET were calculated as indexes of the heterogeneity of regional LV systolic wall motion. EF increased significantly from 20% +/- 8% to 30% +/- 8% (p < 0.05) in patients who received beta-blockade and an ACE inhibitor (n = 5). Furthermore, the coefficients of variation of rET decreased from 27% +/- 13% to 16% +/- 7% (p < 0.05). In contrast, patients treated with an ACE inhibitor only (n = 7) showed no significant improvements in any of these parameters. These results suggest that, compared with an ACE inhibitor alone, beta-blockade improves global and regional LV function in dilated cardiomyopathy by synchronizing myocardial contraction. [ABSTRACT FROM AUTHOR]