Cardiac sympathetic nerve activity can detect congestive heart failure sensitively in patients with hypertrophic cardiomyopathy

STUDY OBJECTIVES: Cardiac sympathetic nerve dysfunction is related to poor clinical outcome in patients with several different heart diseases. However, it is not clear whether cardiac sympathetic nerve activity is useful for predicting the onset of congestive heart failure (CHF) in patients with hypertrophic cardiomyopathy (HCM). The aim of this study was to examine the prognostic value of performing (123)I-labeled metaiodobenzylguanidine (MIBG) scintigraphy in patients with HCM in comparison with other conventional prognostic variables. METHODS: (123)I-labeled MIBG images were obtained from 84 HCM patients without prior CHF. After measurement of cardiac function, the patients were followed up for 9 to 86 months in our hospital. RESULTS: According to the cutoff values for the heart/mediastinum ratio (H/M) on delayed images of control subjects (ie, mean - 1 and 2 SDs), the patients were subdivided into the following three groups: group A (H/M, > 2.11; 34 patients); group B (H/M, < 1.86 to 相似文献   

Clinical features of myocardial triglyceride in different types of cardiomyopathy assessed by proton magnetic resonance spectroscopy: comparison with myocardial creatine

BackgroundMyocardial lipid overstorage may produce cardiomyopathy, leading to dysfunction, but advanced heart failure may cause lipolysis via sympathetic nerve activation. In the failing heart, the creatine kinase system may also be impaired. The aims of this study were to assess myocardial triglyceride (TG) and creatine (CR) in different types of cardiomyopathy and to investigate whether they are related to the severity of cardiac dysfunction.Methods and ResultsIn patients with hypertrophic cardiomyopathy (HCM, n = 8), dilated cardiomyopathy (DCM, n = 12) or ischemic cardiomyopathy (ICM, n = 10), and normal subjects (NML, n = 22), myocardial TG and CR were evaluated using proton magnetic resonance spectroscopy. To assess cardiac sympathetic nerve activity, myocardial MIBG (a radioactive guanethidine analog) uptake was measured in DCM. Myocardial TG was significantly lower in hypertrophic cardiomyopathy (HCM) (1.92 ± 0.99 μmol/g), but higher in ICM (7.59 ± 4.36 μmol/g) than in NML hearts (4.05 ± 1.94 μmol/g). There was no significant difference in TG between DCM (4.84 ± 6.45 μmol/g) and NML. Myocardial CR in HCM (20.4 ± 8.4 μmol/g), DCM (14.8 ± 4.8 μmol/g), and ICM (19.4 ± 6.3 μmol/g) was significantly lower than that in NML hearts (27.1 ± 4.3 μmol/g). Overall, myocardial CR correlated positively with the severity of heart failure estimated by ejection fraction or myocardial BMIPP (a radioactive fatty acid analog) uptake, but TG did not. In DCM, myocardial TG correlated with body mass index, but not with MIBG uptake.ConclusionsMyocardial TG may be related to the specific cause of disease rather than the severity of cardiac dysfunction. In contrast, myocardial CR reflects the severity of heart failure despite different pathoetiologic mechanisms of dysfunction. In DCM, myocardial TG may be affected by an overweight state rather than cardiac sympathetic nerve dysfunction. Thus, myocardial CR has a closer relationship to heart failure severity than does myocardial TG.     

Myocardial creatine concentration in various nonischemic heart diseases assessed by 1H magnetic resonance spectroscopy.

BACKGROUND: Previous (31)P magnetic resonance spectroscopy (MRS) studies demonstrated that the myocardial phosphocreatine-to-ATP ratio offered important information concerning the degree of dysfunction and prognosis in patients with cardiomyopathy. In the present study, we investigated total creatine (CR) levels in various diseased hearts using 1H MRS. METHODS AND RESULTS: Fourteen patients with the following conditions were examined: cardiac amyloidosis (n = 2); hypertensive heart disease (4); valvular disease (2); hypertrophic cardiomyopathy (2); dilated cardiomyopathy (2); restrictive cardiomyopathy (1); and post-operative atrial septal defect (1). Myocardial CR was measured using 1H MRS with point-resolved spectroscopy localization. Overall, myocardial CR levels in diseased hearts were significantly lower than those in the control group [16.5+/-6.0 (n = 14) vs 27.1+/-3.2 micromol/g (n = 10), p < 0.001]. There was a positive correlation between myocardial CR and left ventricular ejection fraction (42.9+/-13.8%, range 19.5-69.1%) despite the different mechanisms of cardiac dysfunction (r = 0.60, p < 0.05). Myocardial CR levels in patients who were hospitalized due to heart failure within 1 year were significantly lower than those in other patients [11.3+/-1.0 (n = 4) vs 18.6+/-5.9 micromol/g (n = 10), p < 0.05]. CONCLUSIONS: Noninvasive measurement of myocardial CR using 1H MRS may be valuable in the assessment of disease severity and prediction of clinical course in various forms of heart disease.     

Cerebral metabolic abnormalities in congestive heart failure detected by proton magnetic resonance spectroscopy

OBJECTIVES: Using proton magnetic resonance spectroscopy, we investigated cerebral metabolism and its determinants in congestive heart failure (CHF), and the effects of cardiac transplantation on these measurements. BACKGROUND: Few data are available about cerebral metabolism in CHF. METHODS: Fifty patients with CHF (ejection fraction < or = 35%) and 20 healthy volunteers were included for this study. Of the patients, 10 patients underwent heart transplantation. All subjects performed symptom-limited bicycle exercise test. Proton magnetic resonance spectroscopy (1H MRS) was obtained from localized regions (8 to 10 ml) of occipital gray matter (OGM) and parietal white matter (PWM). Absolute levels of the metabolites (N-acetylaspartate, creatine, choline, myo-inositol) were calculated. RESULTS: In PWM only creatine level was significantly lower in CHF than in control subjects, but in OGM all four metabolite levels were decreased in CHF. The creatine level was independently correlated with half-recovery time and duration of heart failure symptoms in PWM (r = -0.56, p < 0.05), and with peak oxygen consumption and serum sodium concentration in OGM (r = 0.58, p < 0.05). Cerebral metabolic abnormalities were improved after successful cardiac transplantation. CONCLUSIONS: This study shows that cerebral metabolism is abnormally deranged in advanced CHF and it may serve as a potential marker of the disease severity.     

31P magnetic resonance spectroscopy in dilated cardiomyopathy and coronary artery disease. Altered cardiac high-energy phosphate metabolism in heart failure.

BACKGROUND. The purpose of this work was to further define the value of cardiac 31P magnetic resonance (MR) spectroscopy for patients with coronary artery disease and dilated cardiomyopathy. METHODS AND RESULTS. Blood-corrected and T1-corrected 31P MR spectra of anteroseptal myocardium were obtained at rest using image-selected in vivo spectroscopy localization, a selected volume of 85 +/- 12 cm3, and a field strength of 1.5 T. Nineteen volunteers had a creatine phosphate (CP)/ATP ratio of 1.95 +/- 0.45 (mean +/- SD) and a PDE/ATP ratio of 1.06 +/- 0.53; in four patients with left anterior descending coronary artery (LAD) stenosis, six patients with chronic anterior wall infarction, and four patients with chronic posterior wall infarction, CP/ATP and phosphodiester (PDE)/ATP ratios did not differ from those in volunteers. Twenty-five measurements of 19 patients with dilated cardiomyopathy yielded a CP/ATP of 1.78 +/- 0.51 and a PDE/ATP of 0.98 +/- 0.56 (p = NS versus volunteers). When these patients were grouped according to the severity of heart failure, however, CP/ATP was 1.94 +/- 0.43 in mild (p = NS versus volunteers) and 1.44 +/- 0.52 in severe DCM (p < 0.05), respectively. No correlation was found between CP/ATP and left ventricular ejection fraction or fractional shortening, but correlation of CP/ATP with the New York Heart Association (NYHA) class was significant (r = 0.60, p < 0.005). Six patients with dilated cardiomyopathy were studied repeatedly before and after 12 +/- 6 weeks of drug treatment leading to clinical recompensation with improvement of the NYHA status by 0.8 +/- 0.3 classes. Concomitantly, CP/ATP increased from 1.51 +/- 0.32 to 2.15 +/- 0.27 (p < 0.01), whereas PDE/ATP did not change significantly. CONCLUSIONS. Cardiac high-energy phosphate metabolism at rest is normal in LAD stenosis and chronic myocardial infarction in the absence of heart failure. The CP/ATP ratio has low specificity for the diagnosis of dilated cardiomyopathy. However, CP/ATP correlated with the clinical severity of heart failure and may improve during clinical recompensation.     

Proton magnetic resonance spectroscopy in corticobasal degeneration and progressive supranuclear palsy

Background:   Corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) each have distinctive clinical features, but diagnosis is often uncertain. Our purpose was to evaluate whether localized, single-voxel proton magnetic resonance spectroscopy (¹H-MRS) could distinguish between typical CBD and PSP patients.
Methods:   The study included 10 patients with CBD, nine with PSP and eight age-matched normal healthy subjects. A single-voxel method of 8 cm³ (2 × 2 × 2 cm) was used for ¹H-MRS. The volume of interest was selected at the frontoparietal cortex and the lentiform nucleus.
Results:   Patients with CBD had significantly reduced ratios of N-acetylaspartate to choline-containing compounds (NAA/Cho), N-acetylaspartate to creatine and phosphocreatine (NAA/Cr) in the frontoparietal cortex and lentiform nucleus compared with the normal subjects. Patients with PSP had significantly reduced NAA/Cho and NAA/Cr ratios in the lentiform nucleus, but not in the frontoparietal cortex compared with normal subjects. There was a significant difference in the NAA/Cho in the frontoparietal lobe between CBD and PSP patients.
Conclusion:   ¹H-MRS may indicate different regional patterns of neuronal involvement in CBD and PSP. We suggest that this could be helpful in the differentiation and diagnostic evaluation of CBD and PSP patients.     

Proton magnetic resonance spectroscopy reveals central neuroaxonal impairment in systemic sclerosis

OBJECTIVE:. Involvement of the central nervous system (CNS) in systemic sclerosis (SSc) is rare. Proton magnetic resonance spectroscopy (1H-MRS) assesses in vivo cerebral metabolites. We investigated the biochemical modifications of the CNS in SSc. METHODS: N-acetylaspartate/creatine ratio (NAA/Cr) and choline/creatine ratio (Cho/Cr) at right centrum semiovale (RCS) and at right basal ganglia (RBG) were evaluated by 1H-MRS in 12 patients with limited (lSSc) and 8 patients with diffuse SSc (dSSc) and 20 control subjects. RESULTS: With 1H-MRS, a significant reduction of NAA/Cr ratio at RBG (p < 0.02) and at RCS (p < 0.002) was detected in SSc patients. Cho/Cr ratio was increased (p < 0.02) in the RCS, but not in RBG. In patients with lSSc, a significant reduction of NAA/Cr was detected in RCS but not in RBG. CONCLUSION: Evidence of neuroaxonal damage strongly suggests the existence of CNS involvement in SSc.     

Proton magnetic resonance spectroscopy studies in lactic acidosis and mitochondrial disorders

Summary Congenital lactic acidoses form a large group of disorders that are commonly associated with profound neurological dysfunction. Difficulties are frequently encountered in establishing a diagnosis, and the mechanisms underlying brain damage are poorly understood. We have performed proton magnetic resonance spectroscopy (¹H-MRS) on 24 patients under investigation for suspected metabolic disorder, and have compared the MRS observations of brain lactate with measurements of cerebrospinal fluid (CSF) lactate. We have shown good concordance between the two types of observation, confirming the value of the CSF measurements. Regional variations in brain lactate are detected in some cases, and these may help to elucidate the mechanisms underlying selective brain damage.     

Brain magnetic resonance imaging abnormalities in patients with heart failure

BACKGROUND: Although heart failure (HF) is a common cardiovascular disorder, to date little research has been conducted into possible associations between HF and structural abnormalities of the brain. AIMS: To determine the frequency and pattern of magnetic resonance imaging (MRI) abnormalities in outpatients with chronic HF, and to identify any demographic and clinical correlates. METHODS: Brain MRI scans were compared between a sample of 58 HF patients, 48 controls diagnosed with cardiovascular disease uncomplicated by HF (cardiac controls) and 42 healthy controls. Deep, periventricular and total white matter hyperintensities (WMH), lacunar and cortical infarcts, global and medial temporal lobe atrophy (MTA) were investigated. RESULTS: Compared to cardiac and healthy controls, HF patients had significantly more WMH, lacunar infarcts and MTA, whereas cardiac controls only had more MTA, compared to healthy controls. Age and left ventricular ejection fraction (LVEF) were independently associated with total WMH. Age and systolic hypotension were associated with MTA in HF patients and cardiac controls. CONCLUSION: Our results suggest that cardiac dysfunction contributes independently to the development of cerebral MRI abnormalities in patients with HF. Age and low LVEF are the principal predictors of cerebral WMH in patients with HF and in cardiac controls.     

Cardiovascular magnetic resonance and the evaluation of heart failure

Cardiovascular magnetic resonance (CMR) has established itself as probably the single best way of phenotyping the failing heart. It is the accepted gold standard for measuring cardiac function, volumes, and mass, but within the same scan session additional techniques are available for greater definition. Tissue characterization with the contrast agent gadolinium is well validated and allows the precise visualization and quantification of myocardial infarction. This can be used for viability assessment and to determine heart failure etiology. Dobutamine stress CMR and CMR perfusion hold advantages over conventional techniques. The new frontiers of CMR in heart failure hold the promise of unique insights quantifying myocardial iron, nonischemic fibrosis, microvascular perfusion, plaque characterization, and CMR-targeted intervention. The development and validation of these techniques represent major research challenges for the future. From a clinical perspective, an equal challenge is in increasing the availability of the modality for patients and physicians.     

The role of cardiovascular magnetic resonance in heart failure

Cardiovascular Magnetic Resonance (CMR) is an accepted gold standard for non-invasive, accurate, and reproducible assessment of cardiac mass and function. The interest in its use for viability, myocardial perfusion and coronary artery imaging is also widespread and growing rapidly as the hardware and expertise becomes available in more centres, and the scans themselves become more cost effective. In patients with heart failure, accurate and reproducible serial assessment of remodelling is of prognostic importance and the lack of exposure to ionizing radiation is helpful. The concept of an integrated approach to heart failure and its complications using CMR is fast becoming a reality, and this will be tested widely in the coming few years, with the new generation of dedicated CMR scanners.     

Detrended fluctuation analysis can detect the impairment of heart rate regulation in patients with heart failure with preserved ejection fraction

BackgroundThe impairment of short-term heart rate regulation in patients with heart failure with preserved ejection fraction (HFpEF) can cause acute hemodynamic collapse. Detrended fluctuation analysis (DFA) is a useful tool for the diagnosis of heart diseases and the prediction of mortality. In DFA, the short-term scaling exponent α is decreased in heart failure. However, its change in HFpEF patients remains unclear.MethodsTwenty patients diagnosed with HFpEF [defined as brain natriuretic peptide (BNP) >100 pg/mL, ejection fraction (EF) ≥50%, and without significant valvular disease], 20 diagnosed with non-HFpEF (BNP > 100 pg/mL and EF < 50%), and 20 control subjects generally matched for age and gender were enrolled. Holter electrocardiography was performed, and heart rate variability was calculated. In the DFA, the scaling exponents in 1000 beats were calculated for each 15-min segment and the average of all segments was used. We compared both the short-term (<11 beats, α1) and long-term (≥11 beats, α2) scaling exponents among the three groups.ResultsIn the HFpEF, non-HFpEF, and control groups, α1 was 0.73 ± 0.27, 0.66 ± 0.29, and 1.01 ± 0.20 (p < 0.01), and α2 was 0.95 ± 0.08, 0.88 ± 0.11, and 0.96 ± 0.07 (p < 0.01), respectively. The α1 exponent was significantly decreased in the HFpEF group (p < 0.01 vs. control) and the non-HFpEF group (p < 0.01 vs. control), while the α2 exponent was significantly decreased in the non-HFpEF group only (p < 0.05 vs. HFpEF and control).ConclusionsShort-term heart rate regulation is impaired in patients with HFpEF, while patients with non-HFpEF have both short-term and long-term impairment.     

T-wave alternans associated with heart failure and hypomagnesemia in alcoholic cardiomyopathy.

Marked T wave abnormality developed in a patient with alcoholic cardiomyopathy. The T negativity was of giant size and occurred in an alternating sequence in the presence of sinus rhythm. This change was rapidly transient, disappearing in 3 days. The complete electrocardiographic recovery was temporally related to successful treatment of severe heart failure, normalization of initially low serum magnesium level, and abolition of recurrent ventricular fibrillation.     

Monitoring disease progression in transgenic mouse models of Alzheimer's disease with proton magnetic resonance spectroscopy

Currently no definitive biomarker of Alzheimer's disease (AD) is available, and this impedes both clinical diagnosis in humans and drug discovery in transgenic animal models. Proton magnetic resonance spectroscopy ((1)H MRS) provides a noninvasive way to investigate in vivo neurochemical abnormalities. Each observable metabolite can potentially provide information about unique in vivo pathological processes at the molecular or cellular level. In this study, the age-dependent 1H MRS profile of transgenic AD mice was compared to that of wild-type mice. Twenty-seven APP-PS1 mice (which coexpress mutated human presenilin 1 and amyloid-beta precursor protein) and 30 wild-type mice age 66-904 days were examined, some repeatedly. A reduction in the levels of N-acetylaspartate and glutamate, compared with total creatine levels, was found in APP-PS1 mice with advancing age. The most striking finding was a dramatic increase in the concentration of myo-inositol with age in APP-PS1 mice, which was not observed in wild-type mice. The age-dependent neurochemical changes observed in APP-PS1 mice agree with results obtained from in vivo human MRS studies. Among the different transgenic mouse models of AD that have been studied with 1H MRS, APP-PS1 mice seem to best match the neurochemical profile exhibited in human AD. 1H MRS could serve as a sensitive in vivo surrogate indicator of therapeutic efficacy in trials of agents designed to reduce neurotoxicity due to microglial activation. Because of its noninvasive and repeatable nature, MRS in transgenic models of AD could substantially accelerate drug discovery for this disease.     

Mechanisms of creatine depletion in chronically failing rat heart

The failing myocardium is characterised by energetic imbalance, reflected by reduced phosphocreatine and creatine content. These changes may contribute to cardiac dysfunction, yet mechanisms of creatine and phosphocreatine depletion are poorly understood. Creatine is taken up by the heart via the creatine transporter. We investigated the mechanisms leading to myocardial creatine depletion in heart failure. Therefore rats were subjected to chronic left coronary artery ligation (MI; n = 36) or to sham operation (sham; n = 25). After 8 weeks, hearts were perfused with 14C-creatine buffer to determine creatine uptake rates via the creatine transporter. Total creatine content was determined by HPLC. Creatine transport in sham hearts followed Michaelis-Menten kinetics with a V(max) of 5.9 +/- 0.5 nmol/min per gww. Heart failure led to a significant 30% decrease in intracellular creatine content and to a significant 26% reduction in creatine uptake (V(max) in MI 4.3 +/- 0.4 nmol/min per gww; P < 0.001 vs. sham). We conclude that depletion of creatine/phosphocreatine content in the failing heart is due to reduced sarcolemmal creatine uptake. The creatine transporter may be a potential therapeutic target to prevent energetic imbalance in heart failure.     

Rapid progression from hypertrophic cardiomyopathy to heart failure in a patient with Becker's muscular dystrophy

We describe the case of a 17-year-old boy with Becker's muscular dystrophy (BMD) presenting with rapid progression from hypertrophic cardiomyopathy to heart failure within 2 years. Initial echocardiogram showed severe hypertrophy of left ventricle (LV) and right ventricle (RV) with normal chamber size, and preserved LV systolic function. Microscopic study of cardiac muscle obtained by endomyocardial biopsy of the interventricular septum showed severe hypertrophy of the muscle fibers and interstitial fibrosis. Follow-up echocardiogram 2 years after the first examination exhibited marked dilated LV and RV with severe LV global hypokinesia. Follow-up endomyocardial biopsy demonstrated increased interstitial cellular matrix. Immunohistochemical staining for dystrophin revealed significant loss of dystrophin along the sarcoplasmic membrane of the right biceps brachii muscle, compatible with BMD.