Therapeutic AV block has been preferred in drug-resistant cases, although concurrent pacemaker implantation is mandatory. If it is technically possible to control surgically produced AV block to the first or second degree, this would certainly make conjoined use of a demand pacemaker quite unnecessary. This concept prompted us to undertake an experimental study, in which we succeeded in producing first to third degree AV block in 30 mongrel dogs through ablation of the AV node by applying direct current from the epicardial side. From immediately after starting ablation a stepwise progressive prolongation of the PQ interval was noted, with eventual development of third degree AV block. Histopathologically, the lesion consisted of coagulation necrosis which involved an average of 95% of the AV node in animals developing third degree AV block and an average of 66% in those with first degree AV block. These results suggest that our surgical procedure, if technically refined to permit ablation of the AV node to the desired extent, will provide an acceptable means of treating supraventricular tachyarrhythmia without requiring permanent pacemaker implantation.

It has been widely recognized that the drinking of strongly acid hot spring water often causes gastrointestinal symptoms. However, the research in this subject has been distinctly sporadic.
Fundamental and clinical experiments were undertaken to ascertain the effect of the drinking of Tamagawa Spa on the gastrointestinal mucosa. The property of Tamagawa Spa, Akita prefecture, is acid vitriol spring whose pH value is 1.2, and it contains a large amount of hydrochloric acid and hydrogen sulfide.
1. Studies in Man
The changes of gastric mucosa in 36 subjects after the drinking of hot spring water were observed by gastrocamera or gastrofiberscope.
Varying degrees of hyperaemia were found in all subjects administered non-diluted hot spring water, whereas these change were markedly reduced in subjects administered two times and over diluted hot spring water.
No instances of erosion or ulceration were seen in any of the subjects.
2. Experiments in Animals
Twenty three healthy rabbits, orally administered non-diluted or diluted hot spring water for seven days were autopsied.
The changes of gastric mucosa were similar to those in man, and no significant influence on the jejunal mucosa was seen. Microscopically the affected mucosa revealed degeneration of the epithelial cells of gastric gland and edema of the submucosa.
Based on the critical review of former studies, several important factors were suggested to explain the occurrence of gastric impairment after the drinking of Tamagawa Spa water.

The purpose of this study was to clarify the effect of warm water bathing (40°C) of the hand on the psychologic sweating measured in the opposite palm. The subjects were 2 males and 4 females, aged 38±10 years (26-58 years). The psychologic sweating was estimated by the apparatus developed by Sakaguchi et al (Sakaguchi, M. et al BME 26: 213, 1988). The room temperature was 27 to 28°C and the relative humidity was 60 to 70%. The sensor was attached using adhesive tape on the right palm. Then the psychologic sweating was measured after deep respiration, mental arithmetic, hand grip, bathing in warm water of 40°C at the level of left wrist. The results showed that the mean values of palmar sweating were 15.6 for deep respiration, 16.8 for mental arithmetic, 15.5 for hand grip and 0 for warm water bathing.
Above results suggest that local water bathing of moderate temperature induces a decrease of psychologic sweating, probably due to relaxing effect of the cerebrum.

We reviewed our experience with 19mm size aortic valve prostheses for cases with small aortic annulus. Forty-six patients operated on between 1990 and Septembr 2002 were enrolled in this study. Clinical late assessment was performed to evaluate the incidence of valverelated complications, residual transprosthetic gradient, left ventricular mass index (LVMI), and NYHA functional class. Postoperative echocardiography was performed to evaluate hemodynamic performance of the prostheses. Follow up was 1 to 12.7 years (mean 5.3±3.6). There was no hospital mortality (0%). Actuarial survival rates at 10 years were 81.4±1.5%. The late postoperative peak gradient was 25±11mmHg. LVMI was significantly reduced in late phase. NYHA functional class significantly improved in the late period. Although 19mm size aortic valve prosthesis remains small transprosthetic pressure gradient, LVMI significantly reduced and patient activity was satisfactory maintained in the late period.

Myxoma of the left ventricle is exceedingly rare and to the best of our knowledge not a single case of its recurrence has been reported in Japan. We have recently experienced a case in which a myxomatous tumor of the left ventricle recurred at the same site as the primary lesion 2.5 years after operation and was treated by surgical excision. The patient was a 28-year-old female who, under the diagnosis of myxoma of the left ventricle, underwent surgical removal of the tumor and mitral valve replacement at her age of 25 years. Although her postoperative course was uneventful, she was noticed, at her age of 28 years, of her inaudible prosthetic valve clicks on auscultation at the outpatient service. Echocardiography revealed a tumor mass in the left ventricle, which tended to grow with the elapse of time. Echocardiography on rehospitalization disclosed a mobile cystic tumor on the posterior wall of the left ventricle, while pulmonary arteriography also revealed a movable tumor in the left ventricle. Intraoperatively, there was noted a solid tumor, composed partly of cystic structure, on the posterior wall of the left ventricle and quick pathology led to a suspected diagnosis of myxoma. Since the tumor was found to have involved the ventricular septum and myocardial tissue of the posterior wall of the left ventricle, its complete surgical excision was impossible. The tumor, with its growth pattern and morphology, was diagnosed as a malignant clinical behavior one, although histopathological evidence indicates its benignancy.

Surgery and cryoablation have been the preferred method for treating drug resistant ventricular tachycardia (VT). Cryoablation, the therapeutic usefulness of which has been documented in many reported studies, is nevertheless not free from technical difficulaties. The advent of Bard^® System 6000 Argon beam coagulator (ABC) as a new procedure alternative to cryoablation offered us a hope for solving problems with conventionally used techniques. Preliminary experiments with this device on dog myocardium permitted us to determine therapeutically adequate irradiation time and depth of cauterization and to locate an optimum area of myocardium to be coagulated. Based on these experiences, an attempt was made to use ABC as an adjunct to surgery in the surgical treatment of 4 patients with monofocal non-ischemic VT. In 1 of these 4 patients, VT disappeared postoperatively, making use of antiarrythmia drugs quite unnecessary, while in the remaining 3, a marked diminution of ventricular arrhythmia with a consequent reduction of drug dosage was achieved, use of the device thus being judged to be beneficial. These results led to the conclusion that ABC will provide a valuable adjunct to operation in selected cases of VT and, if the probe and other appliances are further refined, can reasonably be anticipated to be used as frequently as cryoablation.

An emergency percutaneous cardiopulmonary support system (PCPS) was employed 11 arrest victims (5 males, 6 females; mean age 59.3 years) refractory to conventional resuscitation measures. Cardiac operation was subsequently performed in two patients and coronary angioplasty in two. The 7 other patients continued on cardiopulmonary support by PCPS after successful resuscitation. Duration of support was 10.5±9.1 (mean±S. D.) hours, the flow rate was 2.5±0.7l/min, and PCPS was applied 5-70min (mean, 24.9min) following the onset of cardiac arrest. The entire intraluminal surface of PCPS device had been heparin coated, activated coagulation time was maintained about 150 seconds, with or without minimal systemically administered heparin. Seven of 11 patients (63.6%) were successfully weaned from the PCPS. The early survival (<30 days) was 6 patients (54.5%), and late survival was 4 patients (36.4%). We conclude that PCPS can improve survival in patient unresponsive to conventional resuscitation when instituted soon after cardiac arrest.

Between December of 1989 and May of 1993, 7 of 338 patients (2.1%) who underwent median sternotomy for cardiac operations developed mediastinitis. All of these infections caused by Staphylococcus species. Six of seven patients with mediastinitis were successfully treated with debridement, irrigation and omental transposition into the mediastinum. Between December of 1989 and May of 1992, sterile bone wax was used as a hemostatic agent in 233 of these patients. Between June of 1992 and May of 1993 an argon beam coagulator was used in place of bone wax in 105 patients. The incidence of mediastinitis significantly differed in relation to whether patients received bone wax or not (7 of 233 patients who did (3.0%) versus none in 105 patients who did not (0%) p<0.01). We conclude from this study that bone wax may be a promoting agent in postoperative mediastinitis, so the routine use of bone wax should be reconsidered.

Bypass grafting from the ascending thoracic aorta to the common iliac artery was performed to manage proximal hypertension in a patient with atypical coarctation of the thoracic aorta. The patient's history was significant for an acute aortic thrombosis at the level of the diaphragm for which she underwent an axillo-bifemoral bypass grafting as an emergency operation. Although she was doing well following the initial bypass grafting, the second bypass grafting was required to treat proximal hypertension refractory to medical management. The axillo-femoral bypass graft had a smaller diameter and a longer subcutaneous distance, and the blood supply to the abdominal viscera may have been insufficient. The proximal hypertension was well controlled following ascending thoracic aorta to common iliac bypass, because the diameter (16mm) of the graft is larger than that of the axillo-bifemoral bypass graft (8mm).