Antimyosin monoclonal antibody is a specific marker of impaired sarcolemmal integrity resulting not only from ischemia but also from non-ischemic myocardial injury, such as infection, inflammatory, or immunologic reactions, and alcohol or drug intoxication. In addition, antimyosin accumulation has been demonstrated in some forms of cardiomyopathy with unknown as well as known etiologies. Antimyosin positivity appears to indicate precisely the extent of myocardial necrosis and to reflect cardiac dysfunction in an acute stage of active myocardial damage caused by ischemia and inflammation. However, the correlation is not necessarily good in the chronic stages of the disease or in idiopathic cardiomyopathic hearts; in other words, cardiac antimyosin uptake can be detected even in myocardial tissue with a normal histologic appearance independent of the presence of inflammatory responses, myocyte necrosis, or functional or morphologic deterioration. Thus, antimyosin is useful not only for detecting and quantifying acute myocardial necrosis but also for specifically identifying ongoing or latently progressing myocardial degeneration and sarcolemmal disruption, which will certainly lead to myocardial necrosis. These characteristics may contribute to the early detection of myocardial damage and lead to the investigation of pathophysiologic mechanisms. Further progress in immunologic and radiolabeling techniques is necessary for better specificity and less antigenicity against humans in antimyosin monoclonal antibody imaging. (Jpn Circ J 1998; 62: 77 - 82)

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To evaluate the diagnostic value of dobutamine stress electron-beam computed tomography (EBCT) as compared with exercise stress thallium-201 single-photon emission computed tomography (²⁰¹Tl-SPECT) for the detection of myocardial ischemia, 10 patients with proven or suspected coronary artery disease underwent both tests. Nine of the 10 patients also underwent coronary angiography. EBCT images were analyzed objectively to evaluate systolic wall thickening and analyzed segmentally to determine the distribution of the coronary arteries. Dobutamine stress EBCT revealed the presence of ischemia in 59 segments, whereas exercise stress ²⁰¹Tl-SPECT revealed ischemia in 51 segments (agreement=73%). The advantage of dobutamine stress EBCT was demonstrated in the inferior/posterior segments as compared with the results of exercise stress ²⁰¹Tl-SPECT. The overall sensitivity for detecting ischemic regions supplied by coronary arteries with significant stenosis (diameter stenosis > 50%) was 83% for dobutamine stress EBCT and 79% for exercise stress ²⁰¹Tl-SPECT (p=NS), with specificities of 75% and 82% (p=NS). Thus, dobutamine stress EBCT presents a reasonable alternative to exercise stress ²⁰¹Tl-SPECT for the objective assessment of patients with suspected coronary artery disease. (Jpn Circ J 1998; 62: 83 - 90)

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To elucidate whether the mode of left ventricular opacification using sonicated serum albumin (SSA) is dependent upon the severity of left ventricular dysfunction, SSA was administered intravenously to 26 patients with dilated cardiomyopathy, 24 patients with anteroseptal myocardial infarction, and 9 normal control subjects. The left ventricular inflow pattern in echocardiograms on the apical 4-chamber view was classified into 2 types: straight or whirling. The ratio of left ventricular opacified area to left ventricular end-diastolic area, called the percent left ventricular effective fraction (%LVEF), was also calculated. The inflow pattern was straight in all normal control subjects and 9 myocardial infarction patients, whereas 15 myocardial infarction and all dilated cardiomyopathy patients showed the whirling pattern. Percent LVEF was significantly smaller in patients with dilated cardiomyopathy (45±22%, p<0.0001) and myocardial infarction (65±14%, p<0.001) than in normal control subjects (84±7%). The area that was not opacified was observed only in the infarcted area in cases of myocardial infarction, and over wide regions in cases of dilated cardiomyopathy. In addition, there were significant correlations between %LVEF and ejection fraction or peak filling rate. These findings indicate that contrast echocardiography using SSA can reflect sensitively the severity of left ventricular dysfunctions and detect the regions involved in patients with dilated cardiomyopathy and myocardial infarction. (Jpn Circ J 1998; 62: 91 - 96)

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The actual orifice area of a valve is still considered to be a valuable index for assessing prosthetic valve function. Valve orifice area as calculated by Gorlin's formula is, however, not constant but changes in proportion to the transvalvular flow rate. The purpose of the present study was to examine the relationship between orifice area and flow rate across the Björk-Shiley prosthetic valve as calculated by Gorlin's formula, and to modify the formula in a series of patients with the Björk-Shiley prosthetic valve in the aortic position. Fifty-six patients who had received aortic valve replacement with a Björk-Shiley prosthetic valve underwent cardiac catheterization. Prosthetic valve orifice area was calculated by Gorlin's formula and then plotted against flow rate across the valve with respect to valve size. The relationship between orifice area and flow was linear. The discharge coefficient of Gorlin's formula was plotted against flow rate, and a linear correlation was obtained. By substituting Gorlin's formula for an empiric coefficient into the function for transvalvular flow rate, a modified formula that can predict the actual orifice area of the prosthetic valve is obtained. (Jpn Circ J 1998; 62: 97 - 101)

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Optimal treatment for patients with uncomplicated type B dissection remains a matter of debate. From January, 1987, through June, 1996, 43 patients with acute type B dissection were treated exclusively by medical therapy according to our management guidelines. After discharge, aortography and enhanced computed tomography were performed every 6 months to evaluate the diameter of the dissected aorta. All 43 patients survived the acute phase and were discharged alive from the hospital. There was no death related to aortic dissection. Three patients underwent surgical treatment in the chronic phase because of aortic enlargement. Aortic enlargement in 3 additional patients was managed medically. The values for freedom from aortic enlargement for 43 patients at 1, 3, and 5 years were 100%, 91%, and 86%, respectively. The long-term survival rates of patients treated medically and discharged from the hospital are acceptable. (Jpn Circ J 1998; 62: 102 - 105)

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Aneurysms involving the aortic arch were repaired in 12 patients using a technique known as deep hypothermic intermittent circulatory arrest (DHICA). This technique consists of repeated cycles of 20 min of circulatory arrest and 10 min of cerebral and systemic reperfusion. Aneurysms were of the following types: 2 true atherosclerotic aneurysm, 8 aortic dissections, and 2 traumatic aneurysm. There were 2 operative deaths caused by coagulopathy as a result of hepatic failure and difficulty with left ventricular venting. The frequency of circulatory arrest ranged from 2 to 5 cycles, and total circulatory arrest ranged from 20 to 71 min (mean 43.6 min). The lowest tympanic temperature ranged from 17.7 to 19.2 °C. No permanent cerebral complications occurred in 10 patients. We believe that this adjunct technique offers excellent results in the surgical treatment of aneurysms involving the aortic arch. (Jpn Circ J 1998; 62: 106 - 110)

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The effects and problems of intravenous thrombolytic therapy with a bolus injection of mutant tissue plasminogen activator (t-PA) were investigated in 34 patients with first acute myocardial infarction (AMI). In contrast, 114 patients were selected from 1,003 patients with AMI for treatment using intravenous infusion urokinase (UK). Angiography of these 148 patients revealed a complete occlusion of infarct-related artery with no clear contraindications to the study treatment. With the exception of thrombolysis in myocardial infarction (TIMI-3) recanalization 60 min after a bolus injection of mutant t-PA, the patients were given intracoronary UK in addition to mutant t-PA. The study comparisons were assessed using the following criteria: (1) 60-min assessment of recanalization rates, mutant t-PA vs UK; (2) time interval from initiation of thrombolysis to recanalization, mutant t-PA vs UK; (3) angiographic reocclusion rates within 1 month, mutant t-PA alone vs UK vs mutant t-PA plus UK; and (4) intracerebral hemorrhage rates, mutant t-PA alone vs UK vs mutant t-PA plus UK. There were no significant differences in the recanalization rates between mutant t-PA and UK, but there was a significant reduction in the time to recanalization with mutant t-PA (31.8±12.7 min) compared with UK (56.5±6.3 min). There was a significant difference in the reocclusion rates among the 3 treatment groups (20% mutant t-PA alone vs 4% UK vs 0% mutant t-PA plus UK). On the other hand, no significant differences in intracerebral hemorrhage rates among the 3 treatments were observed. In conclusion, thrombolytic therapy with a bolus injection of mutant t-PA achieved more rapid recanalization, but treatment with mutant t-PA led to a high rate of reocclusion. (Jpn Circ J 1998; 62: 111 - 114)

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Intravascular ultrasound (IVUS) imaging enables detailed analysis and precise measurements of vascular cross-sections. However, to achieve a reduction in the existing level of observer variability requires the development of quantitative IVUS. We have developed a fully automatic intraluminal edge detection technique, based on adaptive active contour models and called ADDER (adaptive damping dependent on echographic regions) that allows the quantitation of the intraluminal cross-sectional area (ICSA). Using a 30-MHz mechanically rotated transducer mounted at the tip of a 3.5-F catheter, 58 normal and pathologic arterial segments (from coronary, renal, splenic, iliac, and carotid arteries) were imaged in vitro. These images were analyzed by 2 experts, E1 and E2, who manually traced the intraluminal contour twice for each image, as well as with ADDER. Intra-observer variabilities for ICSAS Were found to be excellent (-1.454±3.51% for E1, 0.96±5.4% for E2). The inter-observer variability was 2.1±4.3%. The success factor for ADDER was 89% . Its intra-observer variability was null, as the method always finds a unique contour. The correlation between the automatically detected ICSA and the manual ICSA was: r=0.99 (y=1.03x+0.89 mm²). Morphometric variations between manually and automatically traced contours, analyzed by the centerline method, were 100±140 mm on average. In conclusion, the ADDER automatic contour detection applied to IVUS images is robust and characterized by small systematic and random errors; therefore, quantitative IVUS is a useful tool in clinical research trials. (Jpn Circ J 1998; 62: 115 - 121)

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In this study we investigated the effects of isoproterenol and enoximone on protamine cardiotoxicity because administration of protamine for heparin reversal during open heart surgery depresses left ventricular function. Eighteen mongrel dogs were entered into this study. After induction of general anesthesia and a stabilization period, a thermodilution catheter was inserted via the jugular vein. Another 2 catheters were inserted into the left ventricle and femoral artery. Heparin and protamine were used in all animals. Heparin dosage was 300 U/kg, and protamine dosage was 4.5 mg/kg. The animals were divided into 3 groups. Six animals received enoximone (5 μg/kg per min), 6 animals received isoproterenol (0.05 μg/kg per min), and 6 animals received no inotropic agent. Measurements were performed before treatment, 5 min after protamine administration, and at 15-min intervals for 1 h. Cardiac output (CO), mean arterial pressure, pulmonary capillary wedge pressure, first derivative of left ventricular pressure (1±) left ventricular systolic pressure, and heart rate were measured. CO was 1582±34 ml/min in the isoproterenol group (I+P), 1684±61 ml/min in the enoximone group (E+P), and 1471±37 ml/min in the protamine group (P) (p<0.05 E+P vs I+P and P) 60 min after protamine administration. The first derivative of left ventricular pressure (dP/dt) was 1995 ±61 mmHg/sec in the I+P group, 2320±85 mmHg/sec in the E+P group, and 1816±48 mmHg/sec in the P group (p<0.05 E+P vs I+P and P). In our experimental study, the isoproterenol and protamine combination did not increase hemodynamic activity. However, isoproterenol alone significantly increased hemodynamic activity as determined by dP/dt values. Protamine administration impairs the effects of beta agonists on the myocardium. In the protamine group, CO and pressure-dependent values were significantly reduced. Isoproterenol administration did not reverse this deterioration because of the loss of the β-receptor activity. Inotropic agents acting through the β-adrenergic system have partial effects on myocardium. Enoximone, a phosphodiesterase inhibitor, reverses deterioration of cardiac function after protamine administration because it increases myocardial function via the phosphodiesterase system. (Jpn Circ J 1998; 62: 122 -126)

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We report a case of hypertrophic cardiomyopathy (HCM) with apical left ventricular aneurysm, which is difficult to review because cases are so rare. A 54-year-old Japanese man was first found to have an electro-cardiograpic abnormality (T-wave inversion at rest) 19 years ago, and non-obstructive apical HCM without identifiable cause was diagnosed by echocardiography, left ventriculography, and clinical findings. After 19 years, he was admitted because of repeated episodes of palpitation and chest oppression at rest. Widespread left ventricular hypertrophy from the anteroseptal wall to the apex with an apical left ventricular aneurysm was detected by echocardiography, left ventriculography, and cardiac magnetic resonance imaging. Histologic examination of the hypertrophic apical myocardium surrounding the aneurysm showed that the myocardial tissue had been extensively replaced by fibrous tissue containing hypertrophic myocardial fibers, and uptakes of [¹²³I]-metaiodobenzyl guanidine (MIBG) and [¹²³I-] β-methyliodophenyl pentadecanoic acid (BMIPP) in single-photon emission photography images were reduced despite high myocardial perfusion. On the other hand, histologic examination of the hypertrophic anterior wall revealed myocardial hypertrophy with disorga-nization; myocardial perfusion and the uptakes of MIBG and BMIPP were preserved. Abnormalities of myocardial fatty acid metabolism and sympathetic neuron activity with preserved perfusion flow and histologic changes such as fibrosis in the apical wall are indicative of apical myocardial injury or ischemia (infarction) without coronary artery stenosis; apical aneurysm may have occurred in severe apical HCM with cavity obliteration up to the midventricular level. (Jpn Circ J 1998; 62: 127 - 131)

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We report on a 37-year-old man with congestive heart failure caused by eosinophilic myocarditis associated with toxicodermia. He developed many annular skin eruptions and peripheral eosinophilia due to reactions against phenobarbital. Right ventricular endomyocardial biopsy revealed extensive infiltration of eosinophils in the myocardium. A drug lymphocyte-stimulating test (DLST) for phenobarbital was positive. His symptoms, cardiomegaly, and cardiac function were improved by discontinuing phenobarbital followed by oral administration of prednisolone. We conclude that this eosinophilic myocarditis must have been induced by an allergic reaction to phenobarbital and that long-term eosinophilia contributed to the myocardial injury. (Jpn Circ J 1998; 62: 132 - 135)

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Moyamoya disease is an occlusive intracranial arteriopathy with abnormal cerebral vascular collateral networks. Although this disease is known to be associated with stenosis of extracranial arteries, such as the renal artery, a case associated with stenoses of the coronary and renal arteries has not been reported. We describe here a 23-year-old man who had effort angina, renovascular hypertension, and asymptomatic moyamoya disease. Arterioangiography revealed bilateral occlusion of the intracranial carotid arteries and stenoses in the left coronary artery and the left renal artery. (Jpn Circ J 1998; 62: 136 - 138)

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The incidence of purulent pericarditis has declined. However, mortality remains high. We describe a case of purulent pericarditis with tamponade caused by Salmonella enteritidis, and emphasize the importance of early recognition, prompt institution of appropriate antibiotic therapy, and early surgical drainage for survival. (Jpn Circ J 1998; 62: 139 - 141)

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A 34-year-old female patient who presented to our hospital had been treated with insulin for diabetes since she was 25 year old. For the previous year she had experienced chest pain on exertion and during hypoglycemia. During both chest pain and exercise tests, ST depression and flattening of the T wave were recognized in leads II, III, aV_F, and V₂-V₆ on the electrocardiogram, and thus ischemic heart disease was suspected. Cardiac catheterization was performed, but no organic stenosis or spasms were found. Hypoglycemia (41 mg/dl) was induced by intravenous injection of rapid insulin (total 18 U, 0.4U/kg). However, no coronary change was seen, although she felt chest pain and the same ischemic electrocardiographic changes occurred. We hypothesized the causes of the ischemic change to be both the effects of insulin on the cardiovascular system and the physiologic stress induced by the existence of microvascular abnormality. Special care should therefore be taken with diabetic patients being treated with insulin or hypoglycemic agents. (Jpn Circ J 1998; 62: 142 - 145)

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A traumatic left bundle branch block (LBBB) is uncommon in a patient with intact atrioventricular conduction. Three of our patients developed LBBB during a left-sided catheterization. Two patients suffered from angina pectoris and the other had an abdominal aneurysm. Two of them had a history of hypertension. None of the patients had ever shown any conduction abnormalities before the catheterization. The electrocardiogram just before the examination was normal in all 3 patients. LBBB was observed when a catheter was introduced into the left ventricle, and lasted 2-4 min without significant change in heart rates. Examination revealed no significant stenosis proximal to the first septal perforator and normal left ventricular contraction in all patients. One patient developed permanent LBBB 14 months later. Catheter-induced LBBB may occur easily with certain anatomical characteristics of the left bundle branch or the distal His bundle, with or without some concealed damage to the conduction system. It is important to keep this complication in mind and to pay adequate attention to patients' electrocardiograms as well as their angiographical findings, especially in those with pre-existing right bundle branch block. (Jpn Circ J 1998; 62: 146 - 149)

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A 55-year-old Japanese woman demonstrated ST-segment elevation in leads I, aV_L, and V₃-V₆ with chest pain both in an ergometer exercise test and on dobutamine stress echocardiography. Although the baseline coronary arteriogram revealed no organic stenosis, total occlusion of the distal portion of the posterolateral branch of the left circumflex artery was observed during dobutamine infusion with ST-segment elevation and chest pain. This is a rare case of documented dobutamine-induced coronary arterial spasm. (Jpn Circ J 1998; 62: 150 - 151)

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