Cardiac phosphorus-31 two-dimensional chemical shift imaging in patients with hereditary hemochromatosis.

Hemochromatosis is a hereditary iron overload syndrome characterized by increased iron storage, followed by liver cirrhosis and is often associated with restrictive cardiomyopathy. The purpose of this study was to detect alterations of cardiac high-energy phosphate metabolism in patients with hereditary hemochromatosis (HHC) prior to the development of structural heart diseases. Therefore cardiac phosphorus-31 two-dimensional chemical shift imaging ((31)P 2D CSI) was employed. Twenty-four male patients (mean age 47.2 +/- 12 years) homozygous for the C282Y mutation in the hemochromatosis associated HFE gene and twenty-four male healthy volunteers (mean age 47 +/- 11 years) as age-matched controls were included in this study. Using a 1.5-Tesla whole-body magnetic resonance scanner, electrocardiograph-triggered transversal 31P 2D CSI was performed. Left ventricle mean phosphocreatine (PCr) to beta-adenosine triphosphate (beta-ATP) ratios of patients with HHC (1.60 +/- 0.41) were significantly decreased in comparison to healthy volunteers (1.93 +/- 0.36; p = 0.004). Furthermore, we detected moderate, negative correlations between left ventricular PCr to beta-ATP ratios and transferrin saturation, cholesterol, low-density lipoprotein as well as triglyceride. This study shows that 31P 2D CSI permits the detection of alterations of cardiac high-energy phosphate metabolism in patients with HHC, but without any evidence for heart disease. The decreased PCr to beta-ATP ratios in HHC might be caused by mitochondrial impairment due to cardiac iron overload.

3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors improve myocardial high-energy phosphate metabolism in men.

PURPOSE: We intended to prove that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors or statins have a beneficial impact on the human myocardial, high-energy, phosphate metabolism. METHODS: The present study included 18 male patients (mean age 49.8 +/- 10.3) with statin-treated, familiar hypercholesterolemia (FH) and 13 male patients with untreated FH (mean age 44.6 +/- 9.5). Twenty-six healthy male volunteers served as controls (mean age 44.2 +/- 12.1). Phosphorus-31, two-dimensional chemical shift imaging (31P 2D CSI) of the heart was performed in all subjects using a 1.5 Tesla whole-body magnetic resonance (MR) scanner. The ratios between phosphocreatine (PCr) and beta-adenosine-triphosphate (beta-ATP) were calculated for the left ventricular myocardium. Furthermore, echocardiographic evaluation and stress tests were performed in all individuals. RESULTS: The untreated patients with FH exhibited a significant decrease in left ventricular PCr to beta-ATP ratios (1.78 +/- 0.34) compared with statin-treated FH patients (2.15 +/- 0.26, p < 0.001) and healthy controls (2.04 +/- 0.26, p = 0.009). The left ventricular PCr-to-beta-ATP ratios of the treated FH patients were in the range of the healthy controls. CONCLUSIONS: Our study shows for the first time an-improvement of the high-energy, phosphate metabolism in the left ventricular myocardium of patients with statin-treated FH compared with untreated FH patients.

Detection of a silent myocardial infarction with phosphor-31 two-dimensional chemical shift imaging (31P 2-D CSI).

BACKGROUND: Phosphor-31 two-dimensional chemical shift imaging (3lP 2-D CSI) is a well-established noninvasive technique in experimental research on regional myocardial ischemia, and it permits in vivo monitoring of high-energy phosphate metabolism in the myocardium without requiring external tracers,wherein phosphocreatinine (PCr) and beta-adenosine triphosphate (beta-ATP) are the main components of investigation. The decrease of PCr is one of the earliest reactions to acute myocardial ischemia, but also fixed defects after myocardial infarction (MI) showed a reduced ratio of PCr/beta-ATP, probably because of are modeling process taking place in the noninfarcted tissue. CASE REPORT: A 55-year-old patient with diabetes mellitus type 1 is reported, who presented within the scope of a study at the University Hospital Innsbruck, Austria, and in whom 31P 2-D CSI helped to detect a so far unknown coronary heart disease (CHD). CONCLUSION: In the presented case, 31P 2-D CSI for the first time helped to reveal a severe CHD and a so far unknown MI,and and if the calculated voxel size was chosen small enough, even a satisfying localization of the lesion became possible.

Impact of aging on cardiac high-energy phosphate metabolism determined by phosphorus-31 2-dimensional chemical shift imaging (31P 2D CSI).

Previous echocardiographic and experimental animal studies have shown that cardiac function, structure, and metabolism change with age. The aim of this study was to evaluate the impact of age on left ventricular high-energy phosphate metabolism. Using a 1.5 Tesla whole-body MR scanner 31P 2D CSI (8 x 8 phase encoding steps, 320 mm field of view) was performed in 76 healthy male volunteers (41.7 +/- 13 years) without any history of coronary heart disease. Fourier interpolation, corrections for T1 saturation effects, the nucleus Overhauser effect, and the blood contamination were applied to the spectroscopic data. The volunteers were divided into two groups, younger (n = 37) and older (n = 39) than 41.7 years. In all volunteers, laboratory specimen were sampled, and transthoracal echocardiography was carried out. Significant differences in left ventricular phosphocreatine (PCr) to beta-adenosine-triphosphate (beta-ATP) ratios (2.16 vs. 1.83, p < 0.001), fasting serum glucose levels (83.3 vs. 98.7 mg/dl, p < 0.001), E/A (1.51 vs. 1.14 p < 0.001), and ejection fraction (EF, 65.3 vs. 59.9%, p = 0.005) were detected between the two groups of volunteers, younger and older than 41.7 years. Moreover, age correlated moderately to well with left ventricular PCr to beta-ATP ratios (r = -0.44), fasting serum glucose levels (r = 0.4), E/A (r = -0.7), left ventricular myocardial mass (r = -0.41), and EF (r = -0.55). In conclusion, our study shows that left ventricular PCr to beta-ATP ratios decrease moderately with age, as suggested by previous experimental animal studies. Additionally, age correlates negatively with E/A, left ventricular myocardial mass, and EF, as reported by previous echocardiography studies. The present study is the first to show the impact of age on left ventricular PCr to beta-ATP values in humans.

Decreased high-energy phosphate ratios in the myocardium of men with diabetes mellitus type I.

AIMS/HYPOTHESIS: To investigate whether alterations in high-energy phosphates occur in the myocardium of persons with diabetes mellitus type I. Microvascular abnormalities and dysfunction via thickening of the basement membrane are known to occur in diabetic patients. Myocardial high-energy phosphates have been shown to be reduced by ischemia, and alterations of the cardiac metabolism are the primary consequence of myocardial ischemia. METHODS: The present study involved 34 male patients (mean age 35.5 +/- 10.1) with diabetes mellitus type I and 35 healthy male volunteers (mean age 36 +/- 8.6) as age-matched controls. Phosphorus-31 magnetic resonance spectroscopic imaging of the heart was performed in all subjects using a 1.5-T whole-body magnetic resonance scanner. The ratios of phosphocreatine (PCr) to beta-adenosinetriphosphate (beta-ATP) were calculated. Moreover, echocardiographic evaluation and stress tests were performed in all individuals. RESULTS: The myocardium of patients with diabetes mellitus type I showed significantly decreased ratios of PCr to beta-ATP compared with healthy controls in the left ventricle (1.90 +/- 0.4 vs. 2.15 +/- 0.3, p < 0.05). We found a moderate negative correlation between the ratio of PCr to beta-ATP in the left ventricle and both, the diastolic left ventricular function (E/A; r = -0.41) and the glycohemoglobin A1c (GHbA1c; r = -0.42). CONCLUSION: This study demonstrates for the first time a decreased ratio of PCr to beta-ATP in the myocardium of persons with diabetes mellitus type I without a known history of coronary heart disease.