Percutaneous transvenous mitral commissurotomy (PTMC) has recently been used to treat mitral stenosis. The aim of this study was to evaluate the usefulness of radionuclide perfusion lung scanning in assessing the effect of PTMC on the relief of lung congestion. We studied 30 patients (7 males and 23 females, mean age 55 years). Perfusion lung scannings were performed within 1 week before and after PTMC. We calculated the ratio of activity in the upper quarter to that in the lower quarter of the right lung (U/L) as an index of lung congestion. After PTMC, the mean mitral valve area increased from 1.1±0.3 to 1.9±0.4cm², the mean left atrial pressure decreased from 14.8±6.3 to 9.1±3.5 mmHg, the mean pulmonary artery pressure decreased from 22.7±8.6 to 17.4±6.3mmHg, and the U/L ratio decreased significantly from 0.89±0.40 to 0.68±0.24 (p<0.0001). The U/L ratio showed greater improvement (4.5%) in patients whose NYHA class improved (n=19) than in those whose NYHA class did not improve after PTMC. The U/L ratio was closely related to mitral valve area, and left atrial and pulmonary artery pressures. The change in the U/L ratio before and after PTMC also reflected symptomatic improvement. In conclusion, U/L ratios obtained from perfusion lung scannings before and after PTMC reflect mitral valve area and pressures, and can be used to assess lung congestion relief after PTMC.

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Patients with congestive heart failure reportedly show a poor correlation between cardiac function and exercise tolerance. Recent studies have demonstrated that skeletal muscle is the main factor that limits exercise tolerance. However, the relationship between high-energy phosphate metabolism in skeletal muscle and exercise tolerance has not been well defined. Exercise capacity was assessed in 35 subjects with myocardial infarction in terms of peak oxygen consumption (peak VO₂) during treadmill exercise with an analysis of expired gases. On the same day, changes in high-energy phosphates in finger flexor muscle during handgrip exercise were measured by magnetic resonance spectrometry. Phosphocreatine (PCr) utilization and the decrease in pH during handgrip exercise were significantly greater in patients with a poor exercise capacity and their time constant of recovery of PCr was prolonged. The ratios of PCr/Pi (Pi: inorganic phosphate) and PCr/HMPA (HMPA: hexamethylphosphoramide) during exercise and the time constant of recovery of PCr were significantly correlated with peak VO₂. These results suggest that skeletal muscle metabolism governs exercise tolerance.

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Forty five patients aged 40 years or younger were treated with coronary intervention in our institution between 1983 and 1994. This young Japanese population had a strong predisposition to risk factors but did not have extensive disease. These patients underwent 50 elective interventional procedures for angina pectoris or old myocardial infarction and 6 direct balloon angioplasty procedures for acute myocardial infarction. The initial successful result was obtained in 41 of the 45 patients (91%). The mean follow-up was 43±35 months. Angiographic follow-up was available in 31 of the 41 eligible patients (76%). Angiographic restenosis was seen in 9 of these 31 patients (29%), and in 12 of the 38 lesions (32%) with initial successful intervention. There were no deaths among the successfully treated patients. Event-free survival rate without death, myocardial infarction, or coronary artery bypass surgery was 94%; however, event-free survival rate without death, myocardial infarction, coronary artery bypass surgery, or repeat intervention was 66% at 43 months. Ninety three percent of the eligible patients were free from angina at follow-up. These short- and long-term results suggest that young Japanese patients can be treated safely and effectively with coronary interventions.

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To elucidate the morphologic characteristics of the left ventricle in patients with hypertrophic cardiomyopathy who developed atrial fibrillation, we studied left ventricular geometry by two-dimensional echocardiography in 92 patients with hypertrophic cardiomyopathy. These patients were divided into two groups; 24 patients with transient or persistent atrial fibrillation (group I) and 68 patients with sinus rhythm (group II). Left ventricular chamber size in group I was significantly smaller than that in group II. Left ventricular chamber size was correlated positively with stroke volume, and was correlated negatively with left ventricular end-diastolic pressure. The incidence of systemic thromboembolism in group I was 7.1% per patient year. In hypertrophic cardiomyopathy, the size of the left ventricle appears to have major pathophysiologic significance in the development of atrial fibrillation. In addition, since patients with hypertrophic cardiomyopathy who develop atrial fibrillation have a potential risk of systemic thromboembolism, prophylactic anticoagulant therapy should be performed in these patients.

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The effects of aprindine on atrial vulnerability were studied in ll patients; 9 with paroxysmal atrial fibrillation (PAF), and 2 with Wolff-Parkinson-White syndrome, aged 19 to 69 (55.9±16.5; mean±SD). Before and 10 min after the intravenous injection of aprindine (1.5 mg/kg), programmed extrastimulation was performed from the right atrial appendage. Atrial vulnerability was assessed by evaluating the repetitive atrial firing zone (RAFZ), conduction delay zone (CDZ), maximum conduction delay (Max.CD) and fragmented atrial activity zone (FAAZ). After the injection, the duration of the P wave and QTc interval was significantly prolonged without any change in blood pressure or heart rate. RAF was observed in 8 patients under control conditions. However, after the injection of aprindine, the RAFZ completely disappeared in 2 patients, was narrowed in 4, and became wider in 1. AF was induced in the remaining patient. The zone significantly reduced (p<0.01) without any change in CDZ or Max.CD. While FAA was observed in 5 patients under control conditions, it completely disappeared in 2 patients, was narrowed in 1, and did not change in the remaining 7 after the injection of aprindine. In patients whose RAFZ narrowed after administration of aprindine, the wavelength, as determined from the atrial effective refractory period and conduction velocity, was augmented. These results indicate that aprindine suppresses atrial vulnerability with an augmentation of the wavelength. However aprindine exaggerated atrial vulnerability in some patients, such that atrial fibrillation was induced.

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The purpose of this study was to evaluate the functional and biochemical effects in immature cardiac myocytes under hypoxic and hypothermic conditions. Cardiac myocytes were isolated from neonatal rat ventricles and cultured for 4 days, after which 12.5×10⁵ myocytes/flask were incubated under 3% hypoxic conditions at 4°C, 10°C, 15°C, 20°C, 25°C, and 37°C for 6, 12, and 24h. After each hypoxic incubation, creatine kinase (CK) and lactate dehydrogenase (LDH) were measured in the incubation medium. The myocytes were then cultured for an additional 24h at 37°C to evaluate the recovery of the myocyte beating rate. In the 4°C and 37°C groups, the myocyte beating rate recovery markedly decreased with increasing incubation times from 78.1% and 97.2% at 6h to 0.0% and 38.4% of the control, which was the beating rate prior to hypoxic incubation, at 24h, respectively. However, in the 10°C, 15°C, and 25°C groups, this value decreased significantly only at 24h. In the 20°C group, beating rate completely recovered in 24h. A marked increase was found in the release of CK and LDH in the 4°C group from 28.5mIU/flask and 232.9mIU/flask at 6h to 83.7mIU/flask and 640.7 mIU/flask at 24h, respectively. However, in the 25°C and 37°C groups, this release was significantly increased only at 24h. In the 15°C and 20°C groups, no significant increases were observed over 24h. Below 15°C, hypothermia induced cellular damage both functionally and biochemically, and the greatest damage was observed at 4°C. Above 25°C, the damage was due to hypoxia. Thus, a temperature of 15°C to 20°C appears to be suitable for hypothermic preservation of immature myocardium.

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A 64-year-old woman without manifestations of Marfan syndrome was referred for the close investigation of a pulsatile abdominal mass. Computed tomographic scans and magnetic resonance images revealed aneurysmal dilatation of the entire aorta, including the ascending aorta and extending to the bifurcation of the aorta, as well as tortuousness of the thoracoabdominal and abdominal aorta. Digital subtraction angiography also showed aneurysmal dilatation of the entire aorta and trivial aortic regurgitation. However, aortic annular dilatation was not found by echocardiography or aortography. The entire aorta was replaced in two stages. First, graft replacement of the ascending aorta, except for the sinus segment, and the aortic arch was performed using an elephant trunk technique under hypothermic cardiopulmonary bypass with selective cerebral perfusion. Twelve weeks later, the remaining aorta, including the descending aorta and extending to the common iliac artery on the right side, and to the common femoral artery on the left side, was replaced with a partial cardiopulmonary bypass using femoral artery and vein cannulation. We believe that patients with mega aorta syndrome are best treated by total aortic replacement. The results in the present case indicate that the elephant trunk technique is useful for extensive aortic replacement in stages, and greatly facilitates the second stage operative procedures.

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Surgical therapy for ventricular septal perforation associated with acute myocardial infarction is thought to reduce ventricular chamber volume and distort the ventricle due to excision of the myocardium. A 69-year-old man underwent elective surgery that used an autologous pericardial patch without excising the myocardium. Intraventricular repair using the autologous pericardial patch enabled preservation of ventricular geometry and chamber volume and did not result in a depression of cardiac function. Moreover, it has been reported that this surgical procedure protects against suture bleeding and decreases the amount of foreign material required, thus possibly reducing the risk of infectious complications.

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A 43-year-old female was admitted for a labile hypertension and depression. High levels of plasma and urinary noradrenaline strongly suggested a pheochromocytoma. However, clinical investigations revealed a normal adrenal gland and thoraco-abdominal region. Venous samples from multiple sites indicated an increase in noradrenaline in the left jugular vein. Using computed tomography and Gadolinium DTPA (diethylene triamine pentaacetic acid)- enhanced dynamic MR (magnetic resonance) imaging, a tumor was discovered in the cerebello-pontine angle. Carotid angiography showed the feeder arteries clearly. Therefore, the tumor was classified as a noradrenaline-secreting glomus jugulare tumor fed by the carotid artery. After embolization and subsequent medical therapy, blood pressure was well controlled. Twenty cases of intracranial pheochromocytoma have been reported to date. This is the second such case in Japan.

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