Clinical symptoms before and after permanent artificial cardiac pacing in 71 patients (35 male and 36 female; averaged age 65.1 years old) with bradyarrhythmia were described. These patients were diagnosed and classified into the following three groups: (1) A-V block (36 cases), (2) Sick sinus syndrome (31 cases), and (3) Atrial fibrillation with slow ventricular response (4 cases). The clinical symptoms shown before pacing were Adams-Stokes attack (66.7%), the limitation of physical activity (22.2%), heart failure (19.4%), palpitation (19.4%), vertigo (16.7%), anginal pain (13.9%) and dyspnea (8.3%).
After the implantation of the pacemaker, Adams-Stokes attack disappeared in all the cases. The limitation of physical activity was improved in younger patients, but such improvement was slightly depressed in the older patients. General symptoms caused by heart failure were also disappeared except in the patients with valvular heart disease. Palpitation was observed more frequently in sick sinus syndrome than in A-V block; it was difficult to eliminate this by pacing. Anginal pain, dyspnea and vertigo were disappeared by pacing.

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In this paper the relationship between the clinical effect of permanent pacing and the cause of death is discussed.
Of 63 patients with implanted pacemakers, 8 died. The causes of death were cerebellar hemorrhage, sudden death, unknown cause, senility, pneumonia, cerebral embolism, myocardial infarction and mesenteric embolization. The mortality of our paced patients was 12.7 per cent. Post-operative mortality (within 30 days of surgery) was 1.6 per cent (one case). However, the cause of this death was unrelated to the pacemaker (myocardial infarction).
When the patients who have died are compared to the living patients, with relation to the average age at the time of initial pacing, we find that the former group was older than the latter. This may be due to natural history.
Electrocardiographic findings reveal that mortality in the supraventricular arrhythmic group was slightly higher than in the atrio-ventricular block group. In the supraventricular arrhythmic group, systemic embolization as the cause of death was remarkable. This may be due to the irregularity and/or stasis of the blood flow in the atria.
Hemodynamic improvement with pacing was quite obvious not only i n the living, but also i n the patients who had died.
After pacing, no Adams-Stokes attacks or death due to congestive heart failure ever occured.
Although patients derive hemodynamic improvement from pacing, it is no guarantee that they will not die from causes unrelated to the pacemaker. Pacing, therefore, is not always effective in prolonging life.

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Recently, there has been an increase in demand for low-noise air-conditioners. The reduction of noise originating from the expansion valve in an air-conditioner is particularly important, since the propagation of noise along the piping system leads to problems for overall low-noise operation. In order to design a low-noise operating valve, it is necessary to understand the flow characteristics of the refrigerant passing through the throttle of the valve. By acquiring knowledge from the visualization of two-phase flow in an old throttle design, we manufactured an expansion valve with a new throttle design that aims for a reduction in noise generation. We compared the performances of the old and new throttle designs by monitoring the refrigerant flow conditions, refrigerant pressures and temperatures, as well as the acoustic noise generation. Flow visualization of the new throttle clearly indicates liquid or bubbly flow upstream; there is no slug flow. These results show a direct contrast to those for the old throttle design, where slug flow can occur upstream under certain operating conditions. There is also a marked reduction in the noise power spectra in the high frequency domain, which is the one that poses particular problems for the human ear.

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