Arterial stiffness is increased in young women with endometriosis.

Endometriosis is a chronic gynaecological disorder that is accompanied by inflammation and oxidative stress. Atherosclerosis has a long subclinical progression in arteries of children and young adults decades before overt clinical manifestations of the disease. In this study, we determined arterial stiffness by measuring brachial-ankle pulse wave velocity (baPWV) in women with endometriosis to assess the presence of subclinical atherosclerosis. We also measured markers of inflammation and oxidative stress in women with endometriosis. baPWV in women with endometriosis aged over 30 years was significantly higher than that in women without endometriosis aged over 30 years (p < 0.05), but not in women aged less than 30. Serum high-sensitivity C-reactive protein level in women with endometriosis was significantly higher than that in controls (p < 0.05). Young women with endometriosis show significantly increased arterial stiffness, suggesting that women with endometriosis need to be cautious of the future onset of atherosclerosis.

Increase in prominence of electrocardiographic J waves after a single dose of propofol in a patient with early ventricular repolarisation.

J waves appear on an electrocardiogram as an elevation of the J point in the terminal portion of the QRS complex. J waves are often benign, but may be associated with malignant ventricular arrhythmias. In some cases, such problems appear to have been precipitated by propofol infusions. We observed a sudden increase in J waves and profound hypotension following a single intravenous dose of propofol in an 84-year-old woman with early repolarisation in the inferior ventricular wall. When early repolarisation (as shown by electrocardiographic J waves) is observed in the inferior ventricular wall pre-operatively, patients should be carefully monitored. Myocardial ischaemia and the use of drugs that might worsen J waves should be avoided.

C-type natriuretic peptide is a Schwann cell-derived factor for development and function of sensory neurones.

Cyclic GMP (cGMP) is known to play important roles for neuronal development and neurite pathfinding. However, the regulatory mechanism that governs the synthesis of cGMP in the nervous system is not well defined. In the present study, we examined the role of C-type natriuretic peptide (CNP), which increases intracellular cGMP upon binding to its receptor, guanylyl cyclase (GC)-B, in the peripheral nervous system. Immunohistochemistry revealed that CNP is demonstrated in Schwann cells, whereas GC-B mRNA is highly expressed in dorsal root ganglion (DRG) neurones. In cultured DRG neurones, GC-B was demonstrated in dendrites of TrkA-positive cells, where it co-exists with cGMP-dependent protein kinase I (cGKI), the major intracellular mediator of cGMP actions. Addition of CNP in the culture medium increased the density of fine neurites, which was accompanied by the increase in phosphorylation of vasodilator-stimulated phosphoprotein, a cGKI substrate. Furthermore, in mice deficient for the CNP gene (CNP-KO), the numbers of TrkA-positive DRG neurones were diminished. Likewise, there were much less cGKI-positive neurones in DRG and cGKI-positive fibres in the dorsal spinal cord of CNP-KO than wild-type mice. Finally, the bone deformity-rescued CNP-KO mice displayed a decreased response to formalin-induced pain compared to wild-type. Taken together, these results suggest that CNP is derived from Schwann cells and plays an important role for the development and function of nociceptive sensory neurones.

Mitral inflow and mitral annular motion velocities in patients with mitral annular calcification: evaluation by pulsed Doppler echocardiography and pulsed Doppler tissue imaging.

AIMS: We evaluated the relationship between the mitral inflow velocities by pulsed Doppler echocardiography and mitral annular motion velocities by pulsed Doppler tissue imaging in patients with mitral annular calcification. METHODS AND RESULTS: Fifty-three patients with mitral annular calcification were divided into two groups: severe mitral annular calcification (n=15, mitral annular calcification bigger than or equal 5mm in width) and mild mitral annular calcification (n=38, mitral annular calcification <5mm in width). In addition, 20 patients with hypertensive heart disease (HHD group) and mild left ventricular hypertrophy but no mitral annular calcification and 30 normal individuals (normal group) were studied. The early diastolic mitral inflow velocity (E) was higher in the severe mitral annular calcification group (0.75+/-0.26 m/s) than in the HHD and normal groups (mild mitral annular calcification, 0.65+/-0.21; HHD, 0.57+/-0.24; normal, 0.55+/-0.15m/s), and the late diastolic mitral inflow velocity (A) was higher in the severe mitral annular calcification group (1.24+/-0.23 m/s) than in the other three groups (mild mitral annular calcification, 0.96+/-0.20; HHD, 0.84+/-0.23; normal, 0.75+/-0.13 m/s). In contrast, the early and late diastolic annular velocities (Ea, Aa) were lower in the severe mitral annular calcification group (Ea: 5.7+/-2.2; Aa: 11.9+/-4.4 cm/s) than in the other three groups (Ea: mild mitral annular calcification, 8.3+/-2.5; HHD, 7.7+/-2.2; normal, 9.0+/-1.8 cm/s; Aa: mild mitral annular calcification, 14.2+/-4.1; HHD, 14.3+/-2.8; normal, 14.2+/-2.1cm/s). Mitral valve area was smaller in the severe mitral annular calcification group (2.6+/-1.0 cm(2)) than in the other three groups (mild mitral annular calcification, 3.1+/-0.7; HHD, 4.1+/-0.7; normal, 4.2+/-0.9 cm(2)). In the mitral annular calcification and normal groups, the A correlated inversely with mitral valve area (r=-0.67, P<0.01) and directly with severity of mitral annular calcification (r=0.65, P<0.01), and the Ea correlated inversely with left ventricular wall thickness (r=-0.37, P<0.01) and severity of mitral annular calcification (r=-0.45, P<0.01). CONCLUSION: Patients with severe mitral annular calcification have higher mitral inflow velocities due to mitral annular restriction and lower mitral annular velocities caused by decreased mitral annular motion and abnormal left ventricular relaxation.

A case of thyrotoxicosis with pancytopenia.

We report a 49-year-old man with primary hyperthyroidism who presented with pancytopenia. The patient presented with leg edema, sinus tachycardia, cardiomegaly, and pleural effusions, all from congestive heart failure. Laboratory data showed pancytopenia and primary hyperthyroidism; echocardiogram showed diffuse hyperkinesis of the left ventricular wall and right ventricular overloading. The bone marrow was moderately hypercellular and compatible with arrested hematopoiesis. Pancytopenia and heart failure improved after administration of methimazole and diuretics. However, high levels of thyroid hormone recurred with pancytopenia 4 months after admission. Therefore, subtotal thyroidectomy was performed, and the levels of thyroid hormones and peripheral blood cell counts have remained normal. Pancytopenia may be caused by hyperthyroidism.

[Clinical significance of coronary flow reserve in hypertrophied heart: comparison with Doppler index, hemodynamics and plasma natriuretic peptide concentrations].

OBJECTIVES: The relationship was investigated between coronary flow reserve and Doppler echocardiographic parameters, hemodynamic parameters and plasma natriuretic peptide concentrations in the hypertrophied heart. METHODS: The subjects were 19 patients with hypertrophied heart due to various etiologies and no significant coronary artery stenosis. All patients were in sinus rhythm. The left ventricular wall thickness, the E/A ratio in transmitral flow velocity pattern and the Doppler index were determined by Doppler echocardiography, and the plasma atrial and brain natriuretic peptide concentrations were measured. At cardiac catheterization, pulmonary capillary wedge pressure and left ventricular end-diastolic pressure were measured, and the coronary flow reserve was obtained by injecting intracoronary adenosine triphosphate into the left anterior descending artery using a Doppler guidewire. RESULTS: Coronary flow reserve in the patients was significantly lower than in 11 normal control subjects (2.50 +/- 0.76 vs 3.90 +/- 0.64, p < 0.001). There were no significant correlations between coronary flow reserve and the left ventricular wall thickness or the E/A ratio. The mean value of the Doppler index in the patients was 0.48 +/- 0.10 and there was a significant negative correlation between coronary flow reserve and the Doppler index (r = -0.73, p < 0.001). The correlation between coronary flow reserve and left ventricular end-diastolic pressure was not significant, but there was a significant negative correlation between coronary flow reserve and pulmonary capillary wedge pressure (r = -0.64, p < 0.01). There were significant negative correlations between coronary flow reserve and atrial (r = -0.62, p < 0.01), or brain natriuretic peptide concentrations (r = -0.56, p < 0.05). CONCLUSIONS: Coronary flow reserve may reflect overall cardiac performance evaluated by the Doppler index and plasma natriuretic peptide concentrations in the hypertrophied heart, and the measurement of coronary flow reserve may be useful for evaluating disease severity in patients with hypertrophied heart.

Serial changes in serum VEGF and HGF in patients with acute myocardial infarction.

The time course of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) release in patients with acute myocardial infarction (AMI) is unknown. Blood samples were obtained at the time of admission and 3, 7, 14 and 21 days later in 32 patients with AMI and 30 control patients. Serum VEGF and HGF, as well as C-reactive protein (CRP) and amyloid A protein (SAA), were determined. Both serum VEGF and HGF levels on admission in patients with AMI were higher than control values and peaked on day 7. VEGF levels in patients with preinfarction angina were higher than in patients with no preinfarction angina, whereas the HGF level did not differ. Both CRP and SAA levels peaked on day 3, and the CRP level on day 3 correlate with both VEGF and HGF levels on day 7. We hypothesized that the serum VEGF level is associated with preinfarction ischemia and the increase in VEGF and HGF on day 7 of AMI may represent a response to acute inflammation.

Plasma and platelet plasminogen activator inhibitor-1 in patients with acute myocardial infarction.

Several studies have demonstrated an increased level of plasma plasminogen activator inhibitor-1 (PAI-1) in patients with coronary artery disease (CAD). However, the concentration of PAI-1 in platelets, which accounts for more than 90% of the blood PAI-1, is unknown in these patients. The present study evaluated the concentrations of PAI-1 and several fibrinolytic factors in the plasma and platelets of patients with CAD and the serial changes in patients with acute myocardial infarction (AMI). All 72 subjects had coronary angiography and were divided into 3 groups: CAD(-) group without coronary artery stenosis or myocardial ischemia (n=20), CAD(+) group with either stable angina pectoris (n=18) or old myocardial infarction (n=12) with coronary artery stenosis, and the AMI group admitted within 24h of symptom onset who underwent successful percutaneous transluminal coronary angioplasty (n=22). The concentrations of plasma PAI-1, tissue plasminogen activator (t-PA), and t-PA x PAI-1 complex were similar in the CAD(-) and CAD(+) groups, but were greater on day 1 in the AMI group compared with the 2 CAD groups. There were no significant differences between the 3 groups in the plasma concentrations of thrombin antithrombin III complex (TAT), alpha2-plasmin inhibitor-plasmin complex (PIC), beta-thromboglobulin (beta-TG), and platelet factor 4 (PF-4). The platelet PAI-1 concentrations did not differ between the CAD(-) and CAD(+) groups, but was greater on day 1 in the AMI group compared to the CAD groups. The platelet beta-TG and PF-4 were similar between the 3 groups. In the AMI group, both the plasma and platelet PAI-1 concentrations were greater on day 1, but the plasma PAI-1 rapidly decreased by day 5 and remained low on day 28 compared with day 1. The platelet PAI-1 concentration gradually decreased by day 5 and was further decreased by day 28. The serial changes of the plasma t-PA and t-PA PAI-1 complex during the course of AMI were similar to those of the plasma PAI-1. A positive correlation was found between the plasma and platelet PAI-1 in all 72 patients, but not in the AMI group alone. These results suggest that the PAI-1 that has accumulated in platelets at the onset of AMI might be released in large amounts into the plasma, resulting in an increase in thrombus formation.

Role of circulating vascular endothelial growth factor and hepatocyte growth factor in patients with coronary artery disease.

Vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) are thought to stimulate endothelial cell proliferation and induce angiogenesis in vivo. However. the precise mechanism responsible for VEGF and HGF release in patients with coronary artery disease is still unknown. We studied serum concentrations of VEGF and HGF in 20 patients with acute myocardial infarction (AMI), 20 patients with stable angina pectoris (AP) who had reversible perfusion defects on stress myocardial scintigraphy, and 16 patients with old myocardial infarction (OMI) who had no reversible defects on stress myocardial scintigraphy. The control group consisted of 20 patients with atypical chest pain who had angiographically normal coronary arteries. Serum VEGF and HGF concentrations were measured by enzyme-linked immunosorbent assay. Both the serum VEGF and HGF concentrations in the early stage of myocardial infarction in the patients with AMI were higher than those in the patients with AP and with OMI, and control patients. The VEGF concentration in the patients with AP was higher than in the patients with OMI, whereas the HGF concentration did not differ in the patients with AP and OMI. The VEGF concentration in AMI patients who had had preinfarction angina on admission was higher than that of patients who had had no preinfarction angina, whereas the HGF concentration did not differ between the two groups of patients. These results suggest that the serum VEGF concentration may reflect myocardial ischemia to a greater degree than the serum HGF concentration.

Fibrinolytic factors, serum lipid and C-reactive protein predicting cardiac events in Japanese patients with coronary atherosclerotic lesions.

Although disturbances of the fibrinolytic system and serum lipid, and the presence of inflammation, may be risk factors for coronary artery disease (CAD), few reports have investigated these relationships in Japanese patients. Data on 106 patients (79 men and 27 women, mean age 62.3 years) with atherosclerotic lesions on the coronary angiogram were evaluated prospectively to identify whether the factors were useful in predicting the risk of coronary events during a follow-up of 50+/-4 months. Of the 106 patients who were followed, 11 patients had coronary events (4 acute myocardial infarction and 7 unstable angina pectoris). In univariate Cox analyses, a high level of tissue-plasminogen activator (t-PA), apolipoprotein CII, C-reactive protein (CRP), and a low level of high-density lipoprotein-cholesterol (HDL-C) was each associated with a significant increase in the risk of future cardiac events. The stepwise model of Cox proportional hazards analysis selected only a high level of t-PA and CRP as predictors of cardiac events. Controlling for any risk factor did not lower the relation between t-PA and the risk of cardiac events, whereas the relative risk of cardiac events in CRP was not significant when controlled for HDL-C. Thus, in prospective data obtained from a cohort of Japanese patients with coronary atherosclerotic lesions, the elevation of t-PA was an independent predictor of subsequent cardiac events. The prognostic role of CRP in cardiac events was related to a low level of HDL-C.

[Hypertensive heart disease with left ventricular diastolic dysfunction demonstrating restrictive hemodynamics: a case report].

A 47-year-old man with hypertensive heart disease and left heart failure due to left ventricular diastolic dysfunction was admitted to our hospital because of emergent hypertension. Chest radiography on admission showed slight cardiomegaly and mild pulmonary congestion with right pleural effusion Echocardiography showed concentric hypertrophy and normal contraction of the left ventricular wall Pulsed Doppler left ventricular inflow velocity wave and pulmonary venous flow velocity wave disclosed restrictive filling patterns. After Ca antagonist, nitrate, and diuretics were administered, blood pressure was normalized, and left ventricular inflow velocity wave showed the relaxation abnormality pattern and pulmonary venous flow velocity wave showed the normal pattern. Radioiodinated iodine-123 metaiodobenzyl guanidine (123I-MIBG) imaging in the state of normalized blood pressure showed decreased heart to mediastinum ratio and increased washout rate. Left heart catheterization and angiography revealed normal end-diastolic pressure and coronary arteries, but coronary flow reserve evaluated with Doppler flow wire and intracoronary adenosine triphosphate administration was impaired: Plasma level of atrial and brain natriuretic peptides, which were markedly elevated on admission, decreased with the improvement of heart failure. Doppler flow velocity patterns, plasma levels of atrial natriuretic peptide and brain natriuretic peptide, cardiac sympathetic nerve activity, and coronary flow reserve might be useful for evaluating the severity of left ventricular diastolic dysfunction in patients with hypertensive heart disease.

Right heart flow dynamics after tricuspid valve annuloplasty. Characteristics and time course.

To evaluate the effect of tricuspid annuloplasty (TAP) on right heart flow dynamics, we analyzed tricuspid inflow velocity pattern, jugular venous pulse and color Doppler flow signal of tricuspid regurgitation (TR) before and after surgery in 16 patients who underwent TAP (TAP group). Cardiac rhythm was atrial fibrillation in all patients. Twelve patients with lone atrial fibrillation served as controls (AF group). Patients in the TAP group were studied before and serially after surgery with a mean follow-up period of 2.7 years. TAP was performed according to the modified De Vega technique in all patients. In a comparison of the most recent data in the TAP group and the data in the AF group, the maximum tricuspid inflow velocity was significantly increased, and both the deceleration time of the tricuspid inflow velocity wave and the y-h interval of the jugular venous pulse were significantly prolonged in the TAP group compared to the AF group. Immediately after surgery, in the TAP group, the area of the TR jet was markedly decreased, and the deceleration time of the tricuspid inflow velocity wave was significantly prolonged compared to those before surgery. The area of the TR jet was dramatically decreased and remained small during the follow-up period. Thus, TAP may produce mild tricuspid stenosis but may also confer sustained preventive effects against TR.

Echocardiographic assessment of right atrial function in patients with myocardial infarction with reference to obstructive lesions of the coronary arteries.

We assessed the relationship between right atrial (RA) function and obstructive lesions of the coronary arteries in 29 patients with recent or old myocardial infarction (MI). Patients were divided into 3 groups according to the location of obstructions as follows: obstruction at the proximal right coronary artery (segments 1 and 2) (RCA proximal group, n=9); obstruction at the distal RCA (segments 3 and 4) (RCA distal group, n=6); and obstruction at the left anterior descending coronary artery (LCA group, n=14). The RA volume and the fractional change in the RA area during atrial contraction (RA %AC) were evaluated by apical 2-dimensional echocardiography. The right ventricular (RV) end-diastolic pressure (RVEDP) was measured in 4 patients in the RCA proximal group and 4 patients in the LCA group. The ejection fraction of the right ventricle (RVEF) was measured by radionuclide angiography or 2-dimensional echocardiography in 7 patients in the RCA proximal group, 5 patients in the RCA distal group, and 7 patients in the LCA group. The RVEF tended to be lower in the RCA proximal group than in the RCA distal and LCA groups. The RA volume was significantly greater in the RCA proximal group than in the LCA group. The RA %AC was significantly smaller in the RCA proximal group than in the RCA distal and LCA groups. There were no significant differences in the early diastolic RV inflow velocity among groups, but the late diastolic RV inflow velocity was significantly lower in the RCA proximal group than in the RCA distal and LCA groups. There was no significant difference in the RVEDP between the RCA proximal and LCA groups. Thus, RA dysfunction in the RCA proximal group appeared to be due to myocardial damage rather than to afterload mismatch. These findings suggest that RA dysfunction may occur in patients with an inferior MI who have an obstructive lesion of the proximal RCA.

[Cardiac amyloidosis with atrioventricular valve thickening and left atrial dysfunction: a case report].

A 70-year-old man with cardiac amyloidosis was referred to our hospital because of exertional chest pain accompanied by ischemic changes on electrocardiography on April 2, 1997. Transthoracic echocardiography revealed a normal size and normally contracted left ventricle without hypertrophy and "granular sparkling" quality of the myocardium, thickening of the mitral and tricuspid valves, and enlargement of the left atrium with reduced booster pump function. Pulsed Doppler mitral inflow velocity wave showed a pseudonormalized pattern, and pulmonary venous flow velocity wave showed a non-compliant pattern. Transesophageal echocardiography revealed thickening and reduced movement of the interatrial septum and reduced flow velocity in the left atrial appendage, suggesting left atrial dysfunction. Adenosine triphosphate (ATP) stress thallium-201 myocardial scintigraphy showed reversible patchy defect mainly in the posterolateral wall. Left ventricular end-diastolic and pulmonary capillary wedge pressures were mildly elevated. Angiography showed normal coronary arteries, but coronary flow reserve measured by administering intravenous ATP in the left anterior descending artery was severely impaired. A rectal biopsy specimen was positive by Congo red staining. Thus, angina pectoris in this patient may be due to amyloid infiltration of the small intramural coronary arteries. Atrioventricular valve thickening and left atrial dysfunction are important clues to diagnose cardiac amyloidosis.

[Evaluation of cardiac function by various cardiac imaging techniques in mitochondrial cardiomyopathy: a case report].

A 39-year-old man with cardiomyopathy due to point mutation of mitochondrial DNA(3243) was admitted to our hospital because of exertional dyspnea accompanied by hearing disturbance and diabetes mellitus. Echocardiography revealed asymmetric hypertrophy of the anterolateral and posterior walls and systolic dysfunction of the left ventricle (fractional shortening = 18%). Pulsed Doppler mitral inflow velocity wave showed a pseudonormalized pattern. Iodine-123 betamethyl-p-iodophenyl-pentadecanoic acid (123I-BMIPP) myocardial scintigraphy showed decreased accumulation in the anterolateral, posterior, and apical walls. Left ventriculography showed moderately decreased ejection fraction (43%), and left ventricular end-diastolic pressure was mildly elevated (18 mmHg). Angiography showed normal coronary arteries, but coronary flow reserve measured by administering intravenous adenosine triphosphate was impaired in the left anterior descending and left circumflex arteries compared to the right coronary artery. Intracellular accumulations of abnormal mitochondria were detected by histologic examination of the cardiac and skeletal muscles. Evaluation of cardiac function showed that the area of myocardial hypertrophy was nearly consistent with the region of decrease in 123I-BMIPP accumulation and coronary flow reserve.

Relationship between flow dynamics in the left atrium and hemostatic abnormalities in patients with nonvalvular atrial fibrillation.

To investigate the relationship between left atrial (LA) flow dynamics and hemostatic markers in nonvalvular atrial fibrillation (AF), 45 patients with nonvalvular AF who had not received anticoagulants were evaluated by transesophageal echocardiography. We determined the LA appendage flow and the presence of LA spontaneous echo contrast (SEC) or thrombus. We measured plasma levels of thrombin-antithrombin III complex (TAT), fibrinopeptide A, D-dimer, beta-thromboglobulin, and platelet factor 4 in peripheral blood as hemostatic markers. The patients were divided into a low-velocity group (n = 19; sum of peak emptying and filling LA appendage flow velocities < 40 cm/s) and a high-velocity group (n = 26; > or = 40 cm/s). The maximum LA diameter was significantly greater and the LA expansion fraction was significantly smaller in the low-velocity group than in the high-velocity group. LA SEC or thrombus was observed in 11 patients (58%) in the low-velocity group, but not in any patients in the high-velocity group (p < 0.001). The plasma levels of TAT, fibrinopeptide A, D-dimer, beta-thromboglobulin, and platelet factor 4 were significantly higher in the low-velocity group than in the high-velocity group. The plasma levels of TAT, fibrinopeptide A, beta-thromboglobulin, and platelet factor 4 were significantly higher in 8 patients without LA SEC or thrombus in the low-velocity group than in 26 patients in the high-velocity group. Patients with nonvalvular AF accompanied by an enlarged and dysfunctioning LA and a decreased LA appendage flow velocity had increased intravascular coagulation-fibrinolysis activity and platelet activation. These abnormalities may be closely related to the thrombogenetic state in patients with nonvalvular AF.

Long-term effects of the angiotensin-converting enzyme inhibitor enalapril on chronic heart failure. Examination by 123I-MIBG imaging.

To examine the long-term effects of the angiotensin-converting enzyme (ACE) inhibitor enalapril on chronic heart failure, 10 patients (7 men and 3 women, mean age: 62 +/- 11 years) with chronic stable heart failure, classified as New York Heart Association (NYHA) functional class 2-3 for more than 3 months, and a left ventricular ejection fraction less than 45% were treated with 2.5-5.0 mg of enalapril once a day for 3-15 months (mean 7 months). The causes of heart failure were old myocardial infarction (n = 7), hypertension (n = 2), and atrial fibrillation (n = 1). Radioiodinated metaiodobenzyl guanidine (123I-MIBG) imaging, radionuclide angiography, and treadmill exercise test were performed before and after the treatment. With enalapril treatment, (1) left ventricular ejection fraction (LVEF) increased significantly from 38.3 +/- 6.9% to 47.5 +/- 14.7%; (2) sub-maximal exercise time increased significantly from 205 +/- 112 to 272 +/- 120 seconds; (3) the heart to mediastinum (H/M) ratio of 123I-MIBG increased significantly (early image: 1.99 +/- 0.38 versus 2.20 +/- 0.50; delayed image: 1.86 +/- 0.44 versus 2.09 +/- 0.51); and (4) the washout rate of 123I-MIBG decreased slightly from 29.1 +/- 9.1% to 25.4 +/- 7.0%. The improvement rate of LVEF was significantly correlated with the improvement rates of the H/M ratio and washout rate after treatment with enalapril. Thus, the long-term effects of enalapril can be observed in the cardiac sympathetic nervous system, and 123I-MIBG imaging appears to be useful for evaluating the therapeutic effects of enalapril on the cardiac sympathetic nervous system in patients with chronic heart failure.