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1.
To evaluate cardiac complications associated with electrical injury, 7 patients with high-tension electrical injury (6,600 V alternating current) underwent 201Tl and 123I-metaiodobenzylguanidine (MIBG) imaging in addition to conventional electrocardiographic and echocardiographic assessments. Electrocardiography showed transient atrial fibrillation, second degree atrioventricular block, ST-segment depression, and sinus bradycardia in each patient. Echocardiography showed mild hypokinesis of the anterior wall in only 2 patients, but 201Tl and 123I-MIBG myocardial scintigraphy showed an abnormal scan image in 6/7 and 5/6 patients, respectively. Decreased radionuclide accumulation was seen primarily in areas extending from the anterior wall to the septum. Decreased radionuclide accumulation was smaller in extent and milder in degree in 123I. MIBG than in 201Tl imaging. These results suggest that even in patients without definite evidence of severe cardiac complications in conventional examinations, radionuclide imaging detects significant damage due to high-tension electrical injury, in which sympathetic nerve dysfunction might be milder than myocardial cell damage.  相似文献   

2.
Left ventricular (LV) systolic function in hypertrophic cardiomyopathy (HCM) is usually normal. Late in the disease, however, LV systolic dysfunction and dilatation are recognized. Although abnormalities in cardiac sympathetic nerve activity in patients with HCM have been demonstrated using (123)I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy, the changes of cardiac sympathetic nerve activity throughout the clinical course from typical to end-stage HCM are unclear. The objective of this study was to evaluate the relationship between abnormalities on (123)I-MIBG myocardial scintigraphy and pathophysiologic changes in patients with HCM. METHODS: We performed (123)I-MIBG scintigraphy on 46 patients with HCM and 18 age-matched control subjects. The patients were categorized into 3 groups: 28 patients with normal LV systolic function (group A), 9 patients with LV systolic dysfunction (group B), and 9 patients with LV systolic dysfunction and dilatation (group C). With planar (123)I-MIBG imaging, the heart-to-mediastinum ratio for early and delayed acquisitions and the washout rate were calculated. With SPECT, polar maps of the LV myocardium were divided into 20 segments. The regional uptake and washout rate were calculated from semiquantitative 20-segment bull's-eye analysis. RESULTS: The early uptake was significantly lower in group C than in the control group (P < 0.01). The washout rate was progressively higher in group A, group B, and group C (P < 0.01). Reduced regional early uptake was found in 2.9 +/- 3.4 (group A), 4.1 +/- 4.7 (group B), and 7.4 +/- 4.3 (group C) segments, respectively. In group C, regional early uptake was significantly reduced, predominantly in the interventricular septal wall, and regional washout rate was increased in the apex and lateral wall. CONCLUSION: These results suggest that cardiac sympathetic nerve abnormalities in patients with HCM may advance with development of LV systolic dysfunction and dilatation and that (123)I-MIBG myocardial scintigraphy may be a useful tool for the evaluation of pathophysiologic changes in HCM.  相似文献   

3.
It is likely that a close association exists between findings obtained by two methods: dobutamine stress echocardiography and 123I-MIBG scintigraphy. Both of these methods are associated with beta-adrenergic receptor mechanisms. This study was conducted to demonstrate the relation between myocardial response to dobutamine stress and sympathetic nerve release of norepinephrine in the failing heart. In 12 patients with heart failure due to idiopathic dilated cardiomyopathy, the myocardial effects of dobutamine stress were evaluated by low-dose dobutamine stress echocardiography: and sympathetic nerve function was evaluated by scintigraphic imaging with iodine-123 [123I] meta-iodobenzylguanidine (MIBG), an analogue of norepinephrine. Echocardiography provided quantitative assessment of wall motion and left ventricular dilation; radiotracer studies with 123I-MIBG provided quantitative assessment of the heart-to-mediastinum (H/M) uptake ratio and washout rate. Results showed that H/M correlated with baseline wall motion (r = 0.682, p = 0.0146), wall motion after dobutamine stress (r = 0.758, p = 0.0043), the change in wall motion (r = 0.667, p = 0.0178), and with left ventricular diastolic diameter (r = 0.837, p = 0.0007). In addition, the 123I-MIBG washout rate correlated with baseline wall motion (r = 0.608, p = 0.0360), wall motion after dobutamine stress (r = 0.703, p = 0.0107), and with the change in wall motion (r = 0.664, p = 0.0185). Wall motion, especially in the myocardial response to dobutamine stress, is related to sympathetic nerve activity in heart failure.  相似文献   

4.
BACKGROUND: Iodine 123-labeled metaiodobenzylguanidine (MIBG) has been used to study cardiac adrenergic nerve activity. Cardiac MIBG uptake is diminished in patients with heart failure. However, it is not known how this reduction is related to regional abnormalities of myocardial wall motion or perfusion. METHODS AND RESULTS: We studied 24 patients with idiopathic dilated cardiomyopathy (ejection fraction <45%) and 15 healthy control subjects using I-123 MIBG cardiac imaging, echocardiographic assessment of wall motion abnormalities, technetium 99m sestamibi perfusion scintigraphy, and hemodynamic assessment. Cardiac MIBG was significantly correlated with ejection fraction (r = 0.67), cardiac index (r = 0.57), left ventricular wall motion score index (r = -0.68), and systolic wall stress (r = -0.61). MIBG was lower in patients than in control subjects (1.43 +/- 0.19 vs 2.05 +/- 0.02; P <.01), whereas the washout rate was higher (P <.01). Moreover, a significant correlation was found between the reduction in MIBG uptake and the severity of echocardiographic wall motion abnormalities in the anterior wall (r = 0.543), apex (r = 0.530), and septum (r = 0.675), as well as with the severity of decrease in resting myocardial perfusion in the anterior wall (r = 0.480) and septum (r = 0.580). CONCLUSIONS: Patients with idiopathic dilated cardiomyopathy show not only global but also regional abnormalities of cardiac sympathetic innervation. The severity of these changes is partially correlated with abnormalities of regional wall motion and myocardial perfusion.  相似文献   

5.
We report a case of "Takotsubo" cardiomyopathy that was considered to be caused by hypercatecholaminemia due to mental stress. Myocardial scintigraphy using 123I-MIBG revealed severe damage to the myocardial sympathetic nerve terminals at the site of reduced left ventricular wall motion on left ventriculography. In this case, cardiac nuclear imaging with 123I-MIBG appeared to be useful for understanding the pathophysiology when combined with ECG and left ventriculography.  相似文献   

6.
Although various noninvasive methods have been used to detect vasospasm, none of them are sensitive enough for patients with sporadic attacks. Because abnormal fatty acid metabolism and cardiac adrenergic neuronal damage are observed in ischemic myocardium, (123)I-15-(p-iodophenyl)-3-R,S-methyl pentadecanoic acid (BMIPP) and (123)I-metaiodobenzylguanidine (MIBG) have recently been proposed as useful tracers for detection of myocardial damage. This study investigated the relationships among the coronary vasospastic regions, abnormal left ventricular regional wall motion, fatty acid metabolism, and sympathetic nerve functions and their changes during treatment in patients with vasospastic angina. METHODS: We evaluated 50 patients with vasospastic angina (25 with clinically documented vasospasm [group A] and 25 with vasospasm induced by ergonovine provocation [group B]) and 25 control subjects who had chest pain but had normal coronary arteries without ergonovine provocation of spasm. Sixteen patients in group A were reevaluated 6 mo after medical treatment. The territorial regions of the vasospasm-induced coronary artery, wall motion determined by left ventriculography, and BMIPP and MIBG uptake were compared. RESULTS: Regions exhibiting a positive reaction to the ergonovine provocation were observed in the right coronary artery in 41 patients, the left anterior descending artery in 33, and the left circumflex artery in 21. Provocation occurred in multiple vessels in 29 patients (58%). Reduction of wall motion was observed in 19 patients (38%). Sensitivity and specificity for the identification of vasospastic angina were 86% (43/50 patients) and 88% (22/25 control subjects), respectively, for BMIPP scintigraphy and 100% (50/50 patients) and 56% (14/25 control subjects), respectively, for MIBG scintigraphy. In the region exhibiting a reduction in left ventricular wall motion, BMIPP or MIBG uptake was decreased. The sensitivity and specificity of determination of vasospasm-induced coronary arteries were 71% (67/95 arteries) and 95% (71/75 arteries), respectively, for BMIPP scintigraphy and 96% (91/95 arteries) and 55% (41/75 arteries), respectively, for MIBG scintigraphy. After 6 mo, during treatment, vasospasm was reinduced by ergonovine provocation in 6 patients (group I) and was not reinduced in 10 patients (group II). Improvements of decreased BMIPP and MIBG uptake were lower in group I (25% +/- 4% and 16% +/- 4%, respectively) than in group II (69% +/- 4% and 50% +/- 3%, respectively; both P < 0.01). The regions in which vasospasm was reinduced exhibited decreased BMIPP and MIBG uptake. CONCLUSION: Abnormal fatty acid metabolism and cardiac sympathetic denervation were observed more frequently than were wall motion abnormalities in the vasospastic region in patients with vasospastic angina. BMIPP and MIBG scintigraphy are highly accurate and noninvasive techniques for determining the presence and location of vasospasm.  相似文献   

7.
PURPOSE: This study was performed to determine whether I-123 metaiodobenzylguanidine (MIBG) scintigraphy can depict myocardial sympathetic nerve abnormalities in Becker muscular dystrophy. MATERIALS AND METHODS: A 34-year-old man with Becker muscular dystrophy underwent Tl-201 and I-123 MIBG scintigraphy sequentially before and 4 months after the beginning of oral administration of enalapril maleate, an angiotensin-converting enzyme inhibitor. RESULTS: Before and during treatment, stress Tl-201 scintigraphy revealed nonreversible myocardial perfusion defects in the anterior, inferoposterior, and apical walls, and I-123 MIBG scintigraphy depicted a region with decreased sympathetic nerve function or innervation. Before treatment, the I-123 MIBG heart count- mediastinum count (H:M) ratio was 2.1 and the washout rate was 21% on delayed images obtained 4 hours after the injection of I-123 MIBG, indicating hyperactivity of the sympathetic nervous system in the myocardium. During treatment, the H:M ratio was 3.0 and the washout rate was 15%. CONCLUSION: With I-123 MIBG scintigraphy it is possible to evaluate an abnormality of the myocardial sympathetic nervous system and the efficacy of administration of an angiotensin-converting enzyme inhibitor in this disease.  相似文献   

8.
Autonomic disorder is not infrequent in patients with akinetic-rigid syndromes, including idiopathic Parkinson's disease. In the advanced stage of Parkinson's disease, abnormal blood pressure responses, such as orthostatic hypotension and abnormal circadian blood pressure rhythm, may occur. Few cases of reduced 123I-metaiodobenzylguanidine (MIBG) accumulation in the heart or limbs of Parkinson's disease patients have been reported. However, whether reduced accumulation is caused by damage to the postganglionic sympathetic nervous system or by central autonomic failure corresponding to abnormalities in blood pressure regulation is unknown. METHODS: We evaluated sympathetic denervation in 32 Parkinson's disease patients using 123I-MIBG cardiac scintigraphy and compared the findings with those for autonomic dysfunction detected by orthostatic hypotension and diurnal blood pressure variation. Cardiac 125I-MIBG accumulation was also determined in an experimental model of Parkinson's disease using mice pretreated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). RESULTS: Cardiac 123I-MIBG accumulation 15 min after injection and 4 h after injection was markedly reduced in the Parkinson's disease patients (heart-to-mediastinum ratio: 1.58 +/- 0.37 and 1.33 +/- 0.28, respectively) compared with 7 healthy volunteers (2.42 +/- 0.27 and 2.60 +/- 0.15, respectively). This reduction was observed even at the earlier stages of physical activity or disease duration and also in patients with normal blood pressure response and variation, indicating that the marked decrease in cardiac 123I-MIBG accumulation may be a special feature of Parkinson's disease. Pretreatment with a total dose of 100 mg/kg MPTP, which is the standard dose used to destroy the dopaminergic neurons in models of Parkinson's disease, significantly reduced cardiac 125I-MIBG accumulation in C57BL/6 mice. Interestingly, the reduction of 125I-MIBG accumulation was still significant when MPTP was reduced to 5 mg/kg. These findings indicated that the postganglionic sympathetic nerves may be damaged by MPTP or unknown toxic substrates in experimental or human Parkinson's disease during the early stage, because dopaminergic neurons and sympathetic nerves are substantially similar in their plasma membrane transporters. CONCLUSION: Cardiac scintigraphy with 123I-MIBG may be used as a new imaging approach in the diagnosis and characterization of akinetic-rigid syndromes, especially Parkinson's disease.  相似文献   

9.
I-123 Metaiodobenzylguanidine (MIBG) is taken up by myocardial sympathetic neuronal endings. Sympathetic neuronal function in 10 patients with cardiomyopathy under stable state were studied by using MIBG and Tl-201 (Tl) SPECT images with 50% cut off level. For myocardial imaging MIBG and Tl were simultaneously injected and collected (dual injection and dual collection mode; Dd mode). Four hours delayed images were also collected. Three types of abnormal findings were noted in MIBG images in combination with Tl images. 1) Enhancement of regional MIBG washout with otherwise normal MIBG and Tl uptake in infero-lateral wall were noted in 5 patients with history of congestive heart failure (Pathophysiologically acceleration of regional sympathetic neuronal function was suspected. Mean washout ratio is 63 +/- 7% vs. 45 +/- 10% in normal region). 2) In 3 patients with dilated cardiomyopathy increase of MIBG/Tl (M/T) ratio was noted in basal septal wall (Sympathetic neuronal function is abnormally accelerated in the region with depressed coronary perfusion. Exaltation of regional sympathetic neuronal function was suspected. Mean M/T ratio is 1.6. Tentative normal range is from 0.8 to 1.20). 3) In 2 patients with dilated cardiomyopathy under severe congestive heart failure defects of MIBG uptake with normal Tl uptake were noted (Sympathetic neuronal function was depleted in spite of normal coronary perfusion. Depletion of myocardial catecolamine was suspected. M/T ratio is 0.75 and 0.7 respectively). Heterogeneous abnormality of sympathetic neuronal function was noted in MIBG images. This findings corresponded to report about heterogeneous myocardial catecholamine concentrations in hearts of recipients of transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

10.
Iodine-123 metaiodobenzylguanidine ([123I]MIBG) is a norepinephrine analog which can be used to image the sympathetic innervation of the heart. In this study, cardiac imaging with [123I]MIBG was performed in patients with idiopathic congestive cardiomyopathy and compared to normal controls. Initial uptake, half-time of tracer within the heart, and heart to lung ratios were all significantly reduced in patients compared to normals. Uptake in lungs, liver, salivary glands, and spleen was similar in controls and patients with cardiomyopathy indicating that decreased MIBG uptake was not a generalized abnormality in these patients. Iodine-123 MIBG imaging was also performed in cardiac transplant patients to determine cardiac nonneuronal uptake. Uptake in transplants was less than 10% of normals in the first 2 hr and nearly undetectable after 16 hr. The decreased uptake of MIBG suggests cardiac sympathetic nerve dysfunction while the rapid washout of MIBG from the heart suggests increased cardiac sympathetic nerve activity in idiopathic congestive cardiomyopathy.  相似文献   

11.
Chronic renal failure (CRF) patients on dialysis frequently show reduced heart rate variability (HRV), which has been reported to be corrected by renal transplantation. Recently, (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy has been used to evaluate cardiac sympathetic innervation, and uremic patients often show marked abnormalities of cardiac (123)I-MIBG uptake. We investigated whether renal transplantation can improve cardiac (123)I-MIBG uptake in patients with CRF on dialysis. METHODS: We analyzed time- and frequency-domain measures of 24-h HRV and cardiac (123)I-MIBG scintigraphy before and 1-3 mo after renal transplantation in 13 CRF patients on dialysis and in 10 control subjects. RESULTS: Both 24-h HRV and cardiac (123)I-MIBG uptake were significantly abnormal in the patients before transplantation compared with the control subjects. After transplantation, (123)I-MIBG washout rate from the myocardium significantly decreased from 46% +/- 21% to 20% +/- 22% (P = 0.006), and the heart-to-mediastinum ratio of (123)I-MIBG uptake in the late image significantly increased from 1.74 +/- 0.39 to 2.06 +/- 0.39 (P = 0.006). On the other hand, HRV measures tended to increase after transplantation but the changes did not reach statistical significance (P > 0.05). CONCLUSION: Renal transplantation provides the improvement of uremic cardiac sympathetic neuropathy assessed by (123)I-MIBG imaging, which may be a more sensitive or at least an earlier marker than HRV.  相似文献   

12.
A 58-year-old man, who had biopsy-proven cardiac sarcoidosis, underwent TI-201 and I-123 MIBG cardiac scintigraphy. Although no perfusion defect was identified by Tl-201, mild heterogeneity of I-123 MIBG uptake was present in the myocardium. The denervated but viable myocardium was demonstrated in the heart with sarcoidosis. Cardiac sympathetic nerve function was impaired in cardiac sarcoidosis, slightly improved with steroid therapy. I-123 MIBG scintigraphy may be useful to assess extent of myocardial involvement and response to therapy.  相似文献   

13.
In order to clarify the characteristics of myocardial ischemia in patients with chronic renal failure (CRF), we performed exercise stress myocardial perfusion imaging with 99mTc-MIBI in 36 patients with CRF. In 18 patients myocardial imaging with 123I-MIBG (MIBG) and 201Tl was performed at rest to evaluate myocardial sympathetic activities: cardiac uptake of MIBG normalized by myocardial perfusion (Uptake Ratio, UR) and myocardial washout rate of MIBG (WO). Exercise-induced perfusion abnormality was observed in 25 patients, and coronary angiography was performed in 19 of them. Among 25 diseased coronary arteries, 18 developed perfusion abnormalities in the myocardial segments which were supplied by each coronary artery. However in 5 patients without coronary artery stenosis and 2 patients with left anterior descending coronary artery disease, transient perfusion abnormalities were observed in the inferior segments. In 6 of them, MIBG imaging was obtained (Group A). MIBG imaging was also performed in 5 patients with transient inferior perfusion abnormality with coronary artery stenosis which supplied the inferior wall (Group B), and 7 patients without perfusion abnormality (Group C). In the patients of Group B, inferior UR was significantly lower than in Group C (0.58 +/- 0.07 vs. 0.68 +/- 0.08, p = 0.0485) and inferior WO was more accelerated than in Group C (18.6 +/- 7.7 vs. 12.1 +/- 6.0%, NS). However anterior UR and Wo levels were identical with those in Group C. In Group A, inferior UR (0.43 +/- 0.05) was significantly lower than in Group B and C, and WO in Group A (27.2 +/- 8.3%) was accelerated significantly compared to that in Group C. Besides in Group A, anterior UR was significantly smaller and WO was greater than in Group B and C. These findings suggested that in some patients with CRF, myocardial ischemia could arise without coronary artery stenosis, and this phenomenon might be related to abnormalities of cardiac sympathetic activity.  相似文献   

14.
A 42-year-old man had the insidious onset of heart failure, and was diagnosed as having restrictive cardiomyopathy. Doppler echocardiography study showed short deceleration time of the E wave and short isovolumic relaxation time on transmitral Doppler flow. He underwent Tl-201, I-123 beta-methyl-iodophenyl pentadecanoic acid (BMIPP) and I-123-metaiodobenzylguanidine (MIBG) cardiac scintigraphy. Tl-201 studies showed normal uptake in the left ventricle indicating normal blood perfusion. I-123 BMIPP and I-123 MIBG showed reduced uptake in the inferior segment of the myocardium, indicating impairment of fatty acid metabolism and sympathetic abnormalities.  相似文献   

15.
The clinical characteristics of reversible left ventricular dysfunction due to "takotsubo" cardiomyopathy have been described, but the origin of this condition remains unclear. This study investigated (123)I-metaiodobenzlguanidine ((123)I-MIBG) myocardial scintigraphy in patients with takotsubo cardiomyopathy. METHODS: Eight consecutive patients with takotsubo cardiomyopathy were studied. Left ventricular wall motion was monitored by echocardiography until wall motion normalized. (123)I-MIBG myocardial scintigrams were performed within 3 d of admission (0 mo) and after the improvement of left ventricular dysfunction (3 mo). Early images were obtained at 30 min after radioisotope injection and delayed images were obtained after 4 h. The heart-to-mediastinum ratio (H/M ratio) and the washout rate were calculated. RESULTS: The mean left ventricular ejection fraction improved significantly (from 42.8% +/- 8.7% to 66.5% +/- 7.9%; P < 0.0001) and normalized after 19.4 +/- 5.4 hospital days. The early H/M ratio was significantly higher than the late ratio at 0 mo (2.16 +/- 0.25 vs. 1.89 +/- 0.24, respectively; P < 0.05), but not at 3 mo. The washout rate was significantly greater at 0 mo than at 3 mo (39.1% +/- 10.2% vs. 25.4% +/- 6.3%, respectively; P < 0.05). CONCLUSION: In patients with takotsubo cardiomyopathy, initial (123)I-MIBG myocardial scintigraphy depicted a unique pattern of ventricular asynergy and indicated the existence of cardiac sympathetic hyperactivity, although coronary blood flow was maintained. These findings strongly suggest that takotsubo cardiomyopathy could be caused by neurogenic myocardial stunning.  相似文献   

16.
A significant reduction of cardiac 123I-meta-iodobenzylguanidine (MIBG) accumulation has been reported in patients with idiopathic Parkinson's disease. However, it is unclear whether this reduction in cardiac sympathetic nerve is caused primarily or secondarily to the degeneration of sympathetic nerve centres which occurs in Parkinson's disease. Therefore, we examined neuronal 125I-MIBG accumulation in mice hearts of an experimental Parkinson's disease model and in sympathetic cells without any neuronal innervation. Cardiac accumulation of 125I-MIBG was determined 4h after intravenous injection of 125I-MIBG in mice pretreated with 1-methyl-4-phenyl-1,2,3,6-tetrahydroxypyridine (MPTP), an inducer of Parkinson's disease. In an in vitro study, uptake of 125I-MIBG was determined in a cultured pheochromocytoma cell line (PC-12), which was pretreated with MPTP. MPTP reduced MIBG accumulation mainly in its neuronal component of mice hearts, suggesting that MPTP impairs cardiac sympathetic nerves to uptake MIBG. Application of MPTP also caused near-complete blockade of 125I-MIBG accumulation in PC-12 cells. In the experimental PD models, it was shown that neuronal accumulation of MIBG was impaired by the direct action of MPTP to the sympathetic cells. These findings support the idea that cardiac sympathetic nerves are primarily impaired in Parkinson's disease despite the presence or absence of systemic autonomic failure.  相似文献   

17.
Background 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy is one of only a few methods available for objective evaluation of cardiac sympathetic function at a clinical level. Disorders in cardiac sympathetic function play an important role in various heart diseases, and MIBG provides an abundance of useful information for evaluation of disease severity, prognosis, and therapeutic effects; this information is of particular value in patients with heart failure, ischemic heart diseases, or arrhythmic disorders. On the other hand, the quantitative indices for MIBG differ between institutions, and evidence has not been sufficiently well established for MIBG, compared with myocardial perfusion imaging, in ischemic heart diseases. Review In view of these difficulties, this review provides fundamental information regarding MIBG, its usefulness for various diseases and future difficulties.  相似文献   

18.
I-123 metaiodobenzylguanidine (MIBG) scintigraphy is a new method to evaluate cardiac sympathetic nerve disturbance in patients with diabetes mellitus. Epalrestat specifically inhibits aldose reductase and improves diabetic neuropathy. The authors report a case of improvement in cardiac sympathetic dysfunction using MIBG scintigraphy with epalrestat therapy. In this case, epalrestat effectively reversed diabetic neuropathy, and MIBG scintigraphy was useful to evaluate the effect of epalrestat.  相似文献   

19.
Little is known about the relation between left ventricular (LV) functional reserve in response to exercise and cardiac sympathetic nervous function in patients with nonobstructive hypertrophic cardiomyopathy (HCM). We investigated whether an assessment of cardiac sympathetic nervous function by myocardial (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy might provide a sign of an abnormal LV functional reserve in response to exercise-induced beta-adrenergic stimulation in patients with HCM. METHODS: Thirty HCM patients underwent (123)I-MIBG scintigraphy and echocardiography at rest and subsequent biventricular cardiac catheterization at rest and during dynamic exercise. LV pressures were measured using a micromanometer-tipped catheter system. The early and delayed (123)I-MIBG images were quantified as a heart-to-mediastinum ratio (H/M). The plasma levels of brain natriuretic peptide (BNP) and norepinephrine (NE) were also measured. RESULTS: Patients were divided into 2 groups according to the delayed (123)I-MIBG H/M: group I consisted of 12 patients with a delayed H/M of < or =1.8 and group II had 18 patients with a delayed H/M of >1.8. Both the percentage increase from rest to exercise in LV isovolumic contraction (LV dP/dt(max)) and the percentage shortening of LV pressure half-time (T(1/2)) as an index of isovolumic relaxation were significantly less in group I than in group II (P < 0.05, respectively). A significant linear correlation was observed between the percentage increase in LV dP/dt(max) and (123)I-MIBG H/Ms (early H/M: r = 0.49, P < 0.01; delayed H/M: r = 0.54, P < 0.005, respectively). A significant linear correlation was also observed between the percentage shortening in T(1/2) and (123)I-MIBG H/Ms (early H/M: r = 0.58, P < 0.001; delayed H/M: r = 0.64, P < 0.0005, respectively). The plasma NE levels were significantly higher in group I than in group II (P < 0.01), whereas the plasma BNP levels were comparable in the 2 HCM groups. CONCLUSION: beta-Adrenergic enhancement of LV function during exercise may depend on the extent of cardiac sympathetic nervous innervation in HCM patients. Resting myocardial (123)I-MIBG scintigraphy can noninvasively evaluate LV functional reserve in response to exercise in patients with nonobstructive HCM.  相似文献   

20.
It remains unclear whether cardiac sympathetic nervous function is disturbed in patients with pulmonary arterial hypertension (PH) and how sympathetic dysfunction is related to PH. METHODS: In this study, (123)I-metaiodobenzylguanidine (MIBG) imaging of the heart, which reveals the sympathetic innervation of the left ventricle, was performed in 7 healthy volunteers without cardiopulmonary disease (control subjects); 55 patients with PH, including 27 with chronic thromboembolic pulmonary hypertension (CTEPH) of major vessels; and 28 patients with primary pulmonary hypertension (PPH). RESULTS: Cardiac (123)I-MIBG uptake, assessed as the heart-to-mediastinum activity ratio (H/M), was significantly lower in the CTEPH and PPH groups compared with that in the control group (P < 0.01). Myocardial MIBG turnover, expressed as the washout rate (WR [%]) from 15 to 240 min, was significantly higher in the CTEPH and PPH groups than that in the control group (P < 0.01). In the PPH group, H/M and WR values of MIBG correlated with the severity of pulmonary hypertension (represented by total pulmonary vascular resistance determined by right heart catheterization), the right ventricular ejection fraction determined by electron beam CT, and other variables but did not correlate well in the CTEPH group. In both groups, patients with H/M > or = 2.0 showed better cumulative survival than did those with H/M < 2.0 (P < 0.05). CONCLUSION: Patients with PH have significant left ventricular myocardial sympathetic nervous alteration. (123)I-MIBG imaging of the heart is useful for assessing the severity of pulmonary hypertension caused by PPH or CTEPH.  相似文献   

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