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This paper presents a slug-churn flow model for predicting turbulent mixing rates of both gas and liquid phases between adjacent subchannels in a BWR fuel rod bundle. In the model, the mixing rate of the liquid phase is calculated as the sum of the three components, i.e. turbulent diffusion, convective transfer and pressure difference fluctuations between the subchannels. The components of turbulent diffusion and convective transfer are calculated from Sadatomi et al.'s [Nucl. Eng. Des. 162 (1996) 245–256] method, applicable to single-phase turbulent mixing, by considering the effect of the increment of liquid velocity due to the presence of gas phase. The component of the pressure difference fluctuations is evaluated from a newly developed correlation. The mixing rate of the gas phase, on the other side, is calculated from a simple relation of mixing rate between gas and liquid phases. The validity of the proposed model has been confirmed with the turbulent mixing rates data of Rudzinski et al. [Can. J. Chem. Eng. 50 (1972) 297–299] as well as the present authors.

A 3-year-old boy suffered from the poor body weight gain under the diagnosis of partial anomalous pulmonary venous connection (PAPVC) to the high portion of the superior vena cava (SVC) associated with ventricular septal defect (VSD) and intact atrial septum (IAS). Preoperative cardiac catheterization revealed the pulmonary to systemic flow ratio 2.6 and mean pulmonary arterial pressure of 21 mmHg. He successfully underwent surgical repair with Williams method using right atrial (RA) flap out and VSD patch closure. Postoperative course was uneventful and echocardiography demonstrated no obstruction at the both routes of neo-SVC and neo-right upper pulmonary venous return.

Osler Rendu-Weber (O-R W) disease (hereditary haemorrhagic telangiectasia) is characterized by an anormality of the peripheral blood vessels which often causes recurrent epistaxis. We presented a case of aortic valve replacement for the patient with O-R-W disease. A 75-year-old woman diagnosed as O-R-W disease with chest pain and dyspnea was admitted. Preoperative transthoratic echocardiography showed severe aortic valve stenosis (AS) with a pressure gradient (from left ventricle to ascending aorta) of 72.5 mmHg. Urgent aortic valve replacement (AVR) was performed after preoperative hormonal (estrogen-progesterone) therapy, that might be effective for bleeding from vascular ectasia. No hemorrhagic tendency was recognized and the postoperative course was uneventful.

An 18-year-old girl with atrial septal defect and Andersen syndrome is reported. Andersen syndrome was described as a hereditary disease characterized by periodic paralysis, prolongation of the QT interval with ventricular arrhythmia and characteristic physical features including low set ear and micrognathia. We successfully performed cardiac operation for this rare associated malformation.

Steinberg method is a modification of Doty extended aortoplasty for supravalvular aortic stenosis (SAS). This modification entails placement of an additional patch in the left coronary sinus. A 3-year-old boy was diagnosed as SAS with aortic valvular stenosis. He was noticed a systolic murmur from 1 month after his birth. Echocardiography showed left ventricular hypertrophy, and pressure gradient of 80 mmHg was measured between the ascending aorta and the left ventricle. Cardiac catheterization revealed severe aortic stenosis at the sino-tubular (ST) junction. We adopted Steinberg 3 sinuses reconstruction. After this operation, there was no pressure gradient at ST junction although aortic valvular stenosis remained and mild aortic valve regurgitation newly developed. As this method can produce a symmetric aortic root, it may reduce aortic valve deformity especially on the left coronary cusp.

Between November 1985 and April 2003, surgical treatment for ventricular septal perforation (VSP) after acute myocardial infarction was performed in 16 patients. Patients were divided into 2 groups by method of operation. One group is infarct exclusion technique (n = 10). The other group is trans right ventricular (RV) approach (n = 6). No significant differences were observed between 2 groups in preoperative states. Operative death rate was high in both groups. Five patients (50%) were died in infarct exclusion group, 4 patients (67%) in trans RV group. Infarct exclusion technique needed longer extracorporeal circulation time (201 +/- 33 min) than trans RV approach (170 +/- 32 min). Although trans RV approach is attractive for its simplicity, 3 cases died of rupture of remained left ventricle infarction area. On the other hand, there were no mortality cases caused by left ventricle rupture in infarct exclusion technique group. As this result, we select infarct exclusion technique as a surgical correction for VSP.

A 37-day-old girl having cor triatriatum with partial anomalous pulmonary venous return was found on emergent admission. Echocardiography and angiography revealed severe pulmonary hypertension with anomalous pulmonary venous return to inominate vein. She still was in respiratory failure after emergent surgical repair because of severe pulmonary hypertension following pulmonary venous obstruction. Prostacyclin is the first Food and Drug Administration (FDA)-approved treatment for advanced primary pulmonary hypertension, which has antithrombotic properties related to its effect on platelets and is a potent vasodilator of both the systemic and pulmonary arteries, and has positive inotropic properties. We started prostacyclin oral internal therapy for her and she recovered from respiratory problems very quickly. Prostacyclin might be effective for pulmonary hypertension before and after surgical repair as primary pulmonary hypertension.

The isolated congenital mitral regurgitation (MR) is a rare anomaly. We have successfully treated a 7-year-old boy who had MR due to a partial defect of the anterior leaflet. Echocardiogram revealed moderate MR at the anterior leaflet as a result of its partial defect. Another MR was also detected at the coaptation zone of the 2 leaflets due to mild prolapse of the anterior leaflet. The mitral valve was approached via atrial septostomy and a partial defect (8 x 6 mm) was found near the postero-medial commissure of the anterior leaflet. Any chordae did not develop around the defect or subvalvular lesions. Other parts of the leaflet was seemed normal and any inflammatory or degenerative changes were not detected in the rest of the leaflets. We have done direct closure of the defect of the leaflet and also added annuloplasty at the posteromedial commissure by modified Kay method.

We report about successful case of human atrial natriuretic peptide (HANP) infusion therapy for early infants who developed congestive heart failure after surgical repair of congenital heart diseases at Ehime Prefectural Central Hospital between January, 1998 through January, 2000. Age at operation ranged from 0 day to 38 days (mean 20 days), and body weight ranged from 1.6 kg to 3.5 kg (2.8 kg as mean). Following HANP infusion at incremental doses of 0.05 to 0.24 microgram/kg/min (0.16 microgram/kg/min as mean), urine output and hemodynamics dramatically improved. Urine output increased from 0.75 ml/kg/hr to 2.79 ml/kg/hr (p = 0.0001) and good urinary output was maintained (3.06 ml/kg/hr) even after discontinuation of the infusion. During the infusion, the heart rate decreased from 157 bpm to 150 bpm and the systemic systolic blood pressure increased from 68 mmHg to 78 mmHg. Central venous pressure decreased from 9.3 mmHg to 7.9 mmHg. There were no adverse effects by HANP infusion. These are successful cases of HANP infusion therapy as the initial treatment of post-operative pulmonary hypertension in this age group. Human atrial natriuretic peptide infusion therapy can be used safely and might be useful in some early infants with CHF, although more investigation is needed.

We investigated the effect of milrinone (phoshphodiesterase III inhibitor) on postoperative hemodynamics in adult eighteen cardiac surgical patients (mean LVEF = 63%). Milrinone was administrated just after the aortic declamping during CPB. Comparing with control group, systemic vascular resistance decreased significantly and sufficient inotropic effect was sustained. In order to keep proper blood pressure much more cathechoramine dose was need when milrinone dose increased during this study. This is supposed that milrinone affected strong vasodilating effect and caused relative hypovolemic condition to the patient who showed good cardiac function. Milrinone causes best efficacy to the patient of poor cardiac function when he showed deconpensation or relatively hypervolemic hemodynamic condition.

We examined the surgical results of total anomalous pulmonary venous connection (TAPVC) retrospectively in 6 infants, who were less than 3 months old and underwent a total repair at Ehime Prefectural Central Hospital between May, 1993 through May, 1998, in terms of the pre, peri, and postoperative management, the site of connection, and the surgical procedures. Aged at operation ranged from 1 day to 86 days (mean 39 days), and body weight ranged from 2.4 kg to 5.5 kg (mean 3.4 kg). All 6 patients had echocardiographic diagnosis and cardiac catheterization but one. In operative procedure, cut back method was done in a patient of paracardiac type of Darling's classification and posterior approach was used in total correction for 4 supracardiac and 1 infracardiac type. There were 3 hospital deaths who had poor conditions before operation, but no late deaths. Surgical results of TAPVC might have been improved with advances in non-invasive diagnosis by echocardiography, and pre and perioperative management. And we should take care of these patients of TAPVC in long term period to make sure that they have no pulmonary venous obstruction.

A 38-year-old man was admitted to our hospital for detailed examination of fever, cough and yellow sputum. At the age of 32, be had mitral prosthesis for the first time, because of mitral regurgitation due to mitral valve prolapse. Four years previously, he had again undergone mitral prosthetic valve replacement due to prosthetic valve endocarditis due to staphylococcus epidemidis. This occasion, staphylococcus aureus was isolated by arterial blood culture. Transesophageal echocardiography detected vegetation attached to the mitral prosthetic valve and paravalvular leakage. The diagnosis was prosthetic valve endocarditis. He underwent a third mitral prosthetic valve replacement. Detection of the source of infection was difficult only by transthoracic echocardiography, and immediate transesophageal echocardiography seemed mandatory to diagnose bacterial endocarditis.

A 59-year-old man who was admitted with hoarseness and diagnosed as aneurysm of the diverticulum of the ductus arteriosus was reported. In our case, enhanced computed tomography and aortography gave reliable informations. Operation was performed through a posterolateral thoracotomy under partial cardiopulmonary bypass. The aneurysm was successfully resected and defect of the aortic wall was covered with Dacron patch. Postoperative course was uneventful. To our knowledge, this is 12th surgically treated case in Japan.

A 68-year-old woman had clinical signs of an acute myocardial infarction. Echocardiography revealed a tumor in the left atrium. Coronary angiography demonstrated total occlusion at RCA#1. On emergency operation a left atrial myxoma was removed and aortocoronary saphenous vein graft to the right coronary artery was performed. The operative correction of coronary arterial obstruction due to cardiac myxoma or thrombus is rare.

A 44-year-old man was transferred to our hospital because of severe congestive heart failure complicated with acute renal failure and hepatic failure. He had been injured in a traffic accident three years before. Echocardiogram demonstrated a large tumor on the anterior wall of right ventricle obstructing RV outflow. Emergent operation was performed with cardiopulmonary bypass. Tumor was too large and invading into RV endocardium partially. RV patch enlargement was performed because it was impossible to resect tumor entirely. CVP was decreased dramatically to 8 cmH2O from 28 cmH2O. Postoperative hemodynamic was stable, but patient died of hepatic failure. Autopsy revealed that tumor was pseudoaneurysm from ascending aorta and ruptured into right ventricle.

A 67-year-old female with mitral regurgitation associated with acromegaly was admitted to our hospital. The cause of MR was torn chordae of posterior leaflet of the mitral valve. A prolapse part of the posterior leaflet was resected and sutured by McGoon's method. Annuloplasty was performed by Kay's method. Postoperative course was uneventful. She recovered well after the operation.

A 38-year-old female was admitted to our hospital because she was suffered from severe dyspnea on effort. She had a history of nasal bleeding, endocarditis, fever, proteinuria, and alopecia at the age of 16, and was diagnosed as SLE. She was suffered from recurrent cerebral infarctions at the age of 35 and 38, and then mitral regurgitation was pointed out. Preoperative examination revealed non-active phase of SLE and UCG showed massive mitral regurgitation. Operative findings showed thrombosed verrucca circumferentially on the mitral valve. Mitral valve replacement (B-S #27) was done with using a felt strip in order to reinforce the mitral annular tissues. Histological findings of the verrucca showed Libman-Sacks endocarditis. Postoperative course was uneventful. Surgical treatment for Libman-Sacks endocarditis is extremely rare.

We have experienced surgical correction of incomplete ECD in a 66-year-old female patient. This is the oldest case in Japanese literatures. Preoperative examination showed mild mitral regurgitation, interatrial shunt (L-R 52%) and moderate pulmonary hypertension (Pp/Ps 0.48). The correction consisted of valvuloplasty of mitral valve and patch closure of ostium primum. The postoperative course was uneventful. The postoperative catheterization showed improved cardiac function.

The present status and problems in the usage of pump oxygenator were analysed through the answer obtained by questionaires which were sent to the 32 of major institution throughout our country. The total number of artificial heart and lung apparatus in use at 32 institutions were 5694, 5472 of roller pump and 222 of pulsatile pump, which showed predominantly in roller tyle. As for the artificial lung, 3151 were bubble oxygenator and 2172 were membrane type, membrane type appeared to be more popular. Only 4 institutions were satisfied with the use of present apparatus, rest of them were not satisfied and preclaimed certain demand of improvement of instrument, especially in 12 institution, compactrization of instruments were advised. The safety of the extracorporeal circulation with the use of present apparatus were accepted by 10 institution, however, complications such as hemolysis and organ failures like renal insufficiency were listed by 21 institutions. It appears to be concluded that much effort to improve the present pump oxygenator regarding to compactirization, safeness and automatic control of the machine are mandatory.

Left-to-right (L-R) shunting across a ventricular septal defect (VSD) often involves a direct VSD-pulmonary arterial component (jet) that surges from the VSD immediately into the pulmonary artery. We used the thermodilution technique in dogs with acute experimental VSD to quantify this component. In dogs with supracristal VSD (n = 7), the direct component represented 76 +/- 4% (mean +/- SE) of the total L-R shunt on average, vs 39 +/- 7% (p less than .001) of the total in dogs with infracristal VSD and the same level of L-R shunting (n = 6). The direct component can be expected to impose additional hyperkinetic forces on the pulmonary artery since it is driven by the left ventricular pressure. Although not yet clinically proven, we speculate therefore that patients with supracristal VSD may be at greater risk of becoming jeopardized by late-onset pulmonary vascular obstructive disease. Since a part of the total shunt other than the direct component dropped into the right ventricle, the right ventricle bore only 24% of the total shunt in supracristal VSD, but 61% in infracristal VSD. We also found that the amount of direct component was decreased, and therefore another part must have increased, as the pulmonary vascular resistance was artificially raised. As a second speculation, therefore, we suggest that patients with supracristal VSD may have less enlargement of the right ventricle than those with infracristal VSD before pulmonary hypertension develops.