After 2 decades of research (1) for a total artificial heart (TAH), the pneumatically driven heart has achieved consistent surgical success with design, implantation and routinely reliable postoperative care (2, 3). More recently, 2 calves lived for over 6 months. Two-month survival rate is now 65%, and the surgical mortality is less than 20%.
However, the electrically powered devices are the most promising for eventual human use (4), because of the best potential for miniaturization of their power source. In contrast the pneumatic power source cannot be miniaturized as well, and requires large, transcutaneous air drive lines. The Department of Energy (DOE) has successfully developed an effective and reliable blood pump which has been implanted in calves (5). Additionally, the integrated electrical energy convertor has successfully been developed. It is very small and can drive mechanically the DOE blood pump in the chest (Fig. 1). The electrohyraulically driven heart (Fig. 2), using a reversing axial flow pump energy converter, has also been developed.

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A New designed total artificial heart, a diaphragm type pump fabricated of Avcothane® has been developed.
This pump is spherical to decrease the volume of ventricle in the thoracic cavity and has no diaphragm-housing junction to prevent the thrombus formation. The calderashaped base plate of pump is designed to have the same surface area as the diaphragm and the length of the full systolic diaphragm profile is exactly the same as the wavy bottom line of the base plate.
The pump was implanted into the thorax of eight calves weighing 90 to 110kg for the fitting and long survival trials.

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Highly reliable, safty and easy operative pneumatic artificial heart driving system was developed.
There are two modes of operation; (a) ECG triggered synchronous pumping (b) variable fixedrate asynchronous pumping. The pneumatic driving system has an adjustable systolic pnematic pulse pressure, diastolic vacume, rate, systolic duration, and diastolic duration.
A storage battery—inverter system with automatic switching are incorporated in the system to insure a continuous source of electrical power and permit fully portable operation of the system for periods of about 60 minutes.

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The establishment of the complete implantable with energy sourse, perment left ventricular assist device, just like a pace-maker is a most desirable technology to save severecoronary ischemic diseases with relatively wide heart muscle damage. For this purpose an intrathoracic left ventricular assist device (LVAD) and a parathoracic left ventricular assist device (PAVD) were developed in our laboratory.
A LVAD was a airdriven, oval shaped diaphragm pump. The human dura mater valves were employed as inflow and outflow valves. The pump was made from the biolized bovine pericardium. Fourteen calves were used in invivo tests which were cotinued over nine months. The reactions of the artificial bypass tract were checked hematologically, biochemically, hemodynamically and histologically using the electromicroscope.
The PVAD was a thin, curved pump which was made from titaniumcasted. The bladder was round shaped and driven by hydraulic power. The pneumo-hydraulic convertor which was a prototype of the implantable engine were implanted into sixteen calves. Adding to previous mentioned testing, the endurance, test of the pump and prototypeengine was achieved in this series. The effect of heat producted from energy source (nucleous or electricity) were examined for long periods.

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In recent three and half years, the eighteen cases of long survivals of goats over one month including 100 days ware experience.
In blood chemical analysis, Ht and Tp decrease gradually after surgical operation, however the values trend to recover one month later, β-globulin shows transiently high value and γ-globulin increases gradually and even three months later. LDH shows trausient increase, however the tests of liver functions, kidney functions, fatty metabolism and electrolytes show no significant change.
The causes of death of the eighteen cases are eight thrombus or emboli, two low cardiac output, two malnutrition, two blood pump rupture, etc.

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The long term survival on calves in total artificial heart replacement will give us in future one of the key points to solve the problem for clinical indication of the replacement. The short term survival cases suggested us the methode of long term survival in artificial heart.
SGOT and SGPT decreased, but yet high level, within one week after operation in the relative long term survival cases. In the cases of long term survival they became normal value within two weeks.
Pyruvate, Lactate and Total Bilirubin decreased, but yet high level, after two weeks, but Alkali Phosphatase did not become normal value for 60 days.
The data of SGOT and Total Bilirubin level showed the influence of open heart and umbalance between driving system and calf itself.
The survivals within one week were given early death by the hemodynamic Schock and open heart. They showed lung complication, renal failure, thrombus formation and low cardiac out put syndrome in autopsy.
The cases of long term survival increased many urinal volume during perfusion, but no hemodynamic Schock. They showed mainly mechanical failure - broken the implanted artificial heart.
I used the data of Freie Universitat Berlin klinikum Westend.

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Recently, it is a big problem that the thrombus is formed inside of ventricle the artificial heart. It is said that there is close relation between the shape of the ventricle and the blood flow mechanism inside it.
Although the flow field in ventricle of the artificial heart is very complicated, it is very important to grasp it for the design of ventricle. This study has made it clear by hydraulic experiment how the flow parttern of artificial heart is affected by the installed position, the angle of inlet or outlet and the direction of valve. From these experiment the sape of ventricle in accordance withe following conditions proved to be optimum; the inlet angle is about 30° with outside opening and the outlet angle is in the range from 60° to 90° with inside opening.

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Left ventricular-aortic bypass or left atrio-aortic bypass under the condition of mitral valve destruction have been performed in 25 dogs with sever left heart failure.
Left heart failure was induced by the ligation of almost all major branches from the ant. descend, circumflex and post. desc. coronary arteries to the left ventricular wall.
Results obtained were as follows.
1. Dogs survived up to 5 days with almost normal appearance. Many of them died suddenly on 2nd or 3rd postoperativeday caused of ventricular fibrillation. Bypass flow rate has been maintained at the higher level than usual cardial output untill their death.
2. Viability of the myocardium has been preserved faily well. However, it seemed to be impossible to prevent them from necrosis without reconstruction of coronary arteries.

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A new designed motor-driven total artificial heart with a diaphragm type pump fabricated of Avcothane® has been basically studied with its extra- and intracorporeal evaluation.
The basic principle of this artificial heart is an alternative pumping of right and left ventricles by the pendulum motion driven by link motion gear system and D-C motor which is implanted intrathoratic and abdominal cavity through diaphragm.
The pumping chamber is spherical having special shaped gloval shaft positioned between the right and left ventricular diaphragm. The capacity of each ventricle was designed 200cc and the space between two diaphragms was adequately filled up with liquid silicone to ensure the smoother driving motion. In the initial design, the shaft between motor and gear system has been manufactured with flexible metalic wire. However due to lack of durability, this was re-designed with solid metalic shaft. In mock circulation, this motor could drivin 12/min. with adequate pressure relationship. Three calves underwent into the implantation. The maximum survival period was 8 hours. The main cause of expiration was lack of durability of mechanical portion of linking.

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Pumping functions of pulsatile blood pump made of segmented polyurethane and plasticized polyvinylchloride were measured under various driving conditions using mock circulation. Simultaneously flow pattern in the pumping chambers was analyzed by flow visualization technique. These findings demonstrate that imperfect driving conditions produce the region where the flow rate extremely decreases and that the decrease in flow rate causes thrombus formation in the pumping chamber.

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A new air driven artificial heart device developed for clinical reality was evaluated in in-vivo acute experiments. The left heart asist pump was connected left atrium and descending aorta of beagle dog. Left ventricle pressure, aortic pressure, left atrial pressure, bypass flow and air pressure wave fome were measured under synchronize and unsyncronize pumping with ECG. As conclusion, it become clear that ttis device could apply not only to any types of assist heart, but also to total artificial heart.

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Analysis of intrinsic beats in 29 patients with implanted pacemakers were performed by inhibition tests. During the inhibition test intrinsic beats occured after ventricular asystole of short duration in the patients with A-V block. The intrinsic beats had tendencies of prolongation of R-R interval, widening of QRS duration and increase of incidence of ventricular rhythm during the pacing periods. These findings may indicate some progressive deterioration of conduction systems of the hearts. In the patients with S. S. S., no apparent changes were observed, except some prolongation of R-R intervals.

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1. In view of an increasing number of patients with implanted cardiac pacemakers, the systematization of care of patients who reside in remote places by means of telephone transmission of stimulating pulse wave is planned.
2. By the use of a pacergram (developed through joint effort of Nihon Koden Co. Ltd.), it is passible to transmit not only ECG but also the waveforms of pacemaker pulse.
3. This will make the case of patients with pacemakers safer and easier.

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An experience of pacemaker implantation in newborn with congenital complete A-V block and without other intracardiac defects was presented. About ten weeks prior to birth, it was that her fetal heart rate was 45 beats per minite. She was born on Jan. 12, 1978 by Cesarean section at Osaka Prefectural Hospital and weighed 3640gr. At birth the heart rate was 43 beats per minite. A chest roentgenogram revealed cardiomegaly with cardiothoracic ratio of 67per cent. The electrocardiogram showed complete heart block with a ventricular rate of 43, an atrial rate of 150 and the duration of QRS complex of 0.06sec.
When 2 days old, she was treated by temporary pacing because she was in frank cardial failure with hepatomegaly and respiratory distress and these was no apparent improvement with the temporary administration of either atropine or Isuprel. She improved immediately with clearing of the heart failure and definite reduction of heart size and hepatomegaly.
Then a myocardil electrode (Medtronic 5815) was fixed on the wall of the right ventricle by left thoracotomy and a unipolar demand pacemaker (Medtronic 5973) was positioned on the left side of subcutaneons abdominal wall.
She tolerated the operative procedure. She has continued to be in good health for eight months. She will be the youngest person to receive a pacemaker implant in Japan.

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Bipolar electrode configuration is superior to the unipolar electrode in our aspects. The advantages of the bipolar are the redundancy of having two electrodes in the heart. This system avoids the possible complication of muscle twiching or interference by myopotentials. There is no significant difference of threshold and of sensing function between both systems.

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Since 1969, implantation of pacemakers has been carried out mainly for the treatment off complete atrioventricular block in the 2nd Department of Surgery, Tottori University School of Medicine. By the end of this August, 50 cases were experienced and to 17 of these patients, generator exchange was performed 29 times.
Since the first implantation in 1969, the number of implantation has increased rapidly every year. The energy source of the generator was changed from the Hg battery to the long acting Li battery since 1976.
As our criteria for the generator exchange, 2 years after implantation is determied as the elective exchange as a rule. As for the emergency and semiemergency exchange, the following cases were decided: the frequency of stimulation shows increase over 5% of immediately after implantation; and disruption and infection of wound are seen over 1 year after implantation.
Details of the 29 times exchanges were 18 cases of elective exchange (62%) and 11 cases of emergency and semiemergency exchanges. As seen, the latter was more frequent than expectation.
The decreasing rate of stimulation frequency was studied about 11 cases in which recordings were sufficient among 18 cases of elective exchange. The mean of 5.4% was obtained, though not calculated uniformly, since types of generator, levels of stimulation and ways of stimulation were different.
This value may become the rough criterion for the exchange of the Hg battery generator.
By the way, the decreasing rate of the Li battery 2 years after implantation, as compared with controls, hardly changed.
Details of the 11 emergency and semiemergency exchanges were 2 cases of disruption of endocardial electrode, 1 case of complete consumption of the battery, 2 cases of pacing failure supposed to be due to the penetration by the myocardial electrode of the wall of the right ventricule, 4 cases of infection of the implanted site, 1 case of pressure necrosis of the skin and 1 case of unknown cause.
The infection of implanted wound was frequent in case which required a long time for the implantation procedures, preparation of insertion vessels and fixation of the electrode tip in the roentgen fluoroscopic room.
The above-described complications could be sufficiently prevented by strict operators, disinfection of the operationsfield, potent and effective use of antibiotics and mastery of implantation technique. Infection and disruption of electrode does not always become the absolute cause of generator exchange. From the points of aging of implanted patients and popularization of the long acting Li battery, to the cases over 1 year after implantation of the Hg battery, exchange to the generator using the Li battery can be considered.

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During past 13 years, 115 patients underwent the implantation of cardiac pacemaker. Nintythree out of these patients survived over 6 months after the implantation of pacemaker. The change of NYHA functional classification and social rehabilitation after pacemaker implantation were studied in 82 survivors and the cause of death was analysed in 11 patients who died. The causes of death were as follows; congestive heart failure in 3, primary myocardiopathy in 1, sudden death in 1, cancer in 2, apoplexy in 1, pneumonia in 1, perforative peritonitis in 1, and nephritis in 1.
Significant improvement of symptoms estimated by the NYHA functional classification was obtained in 69 patients. In 7 patients, the NYHA classification was not changed or slightly improved. In these patients, 3 had tachycardia and 4 had congestive heart failure preand postoperatively.
The rate of social rehabilitation was 62.0%. This value disclosed rather unsatisfactory in comparison with the postoperative NYHA classification. On the other hand, 2 female patients with complete A-V block were safely delivered after implantation. Their rate-output curves made flat type which showed that cardiac output was independent on the wide range of pacing rate.

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Three hundred patients with pacemaker implant were followed up. Transvenous endocardial leads are reliable. Ten years longevity of endocardial electrode is approximately 85 percent. Patient's survival curve is getting better, mainly because of wider indication of pacemaker implant. Patients with sick sinus syndrome resulted in better prognosis than those with complete A-V block.

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In the series of 91 patients, who received permanent pacemakers, 85 patients had primary implantation of transvenous endcardial electrodes and 6 had epicardial electrodes. Of 85 primary transvenous electrodes implanted patients, 10 patients required reposition or reimplantation of the electrode. The main problem was dislocation of the catheter tips, which occurred in 5 cases. Stimulation of the diaphragm was noticed in two patients. Other complications of transvenous implantation included mycardial perforation, electrode break down, insulation defect of the wire and infection, one for each.
In another ten patients, exchange to epicardial pacing was necessary because of dislocation (5 cases), infections (2 cases) and electrode break down, diaphragmatic stimulation and increase in threshould, one for each.

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One handred and twelve pacemakers were implanted in 78 patients.
Malfunction of pacemaker developed in 20 patients. Electronical failure such as generator or wire trouble was found in 7 cases (35%). Causes of failure were in the host side in other 13 cases (65%). Among them it was due to rising threshold in six case. of which three developed malfunction when old generator had been changed to a new one of low output-long life.
Degeneration of myocardium are found in many case of sick sinus syndrome and trifascicular block, so at the time of implantation of pacemaker in these patients, attention must be paid to select of generator and electrode. Recently we have used pacing-analyzer by which maximum threshold and R-sensing are measured. Endocardial electrocardiogram during operation are recorded from catheter electrode. These method and procedure should been performed for prevention of those complications.

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Sinus tachycardia happens to cause cardiac dysfunction in cases immediately after valve replacement or coronary surgery. The method of selective cooling of the sinus node has been studied to reduce the heart rate in these patient. The effect of the cardiac surface warming under sinus node cooling has also been investigated to control of the cardiac contractility for treatment of the postoperative low output syndrome.
A small vinyl sack was attached to the junction of superior vena cava and right atrium (sinus node portion) and was perfused through a vinyl circuit with cooled Ringer solution (3°C). Intra-pericardial cavity was perfused for cardiac surface warming with warmed Ringer solution (40°C).
Experimental study revealed that the cooling reduced the temperature of the sinus node to 34°C resulting in about 10% reduction of the heart rate which was dependent on the sinus node temperature and reversible. By cardiac surface warming, the two dimentional strain gauge sutured to the right ventricular wall indicated some increase in muscle shortening. Clinical application of the sinus node cooling was performed in two postoperative cases, artificial valve replacement for aortic insufficiency and radical operation for Fallot's tetralogy. Postoperative sinus tachycardia in the patients was successfully controlled and the blood pressure improved.

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Pacing failure due to elevated threshold is the most difficult problem in electrical stimulation of the heart. It is important for the prevention of this pacing failure to wedge the electrode into a low threshold position. But the measurement of the threshold is troublesome, and particularly the judgment of the point is difficult on intermittent pacing. Each measures the threshold on his own level, so the value may be differ with which another have measured.
We have developed the new device Automatic Threshold Analyzer (KU-800). This device replies the threshold automatically. The benefits are easiness, making better time, safety, and reappearance of the value.

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In 150 patients with a pacemaker, voltage and current at threshold, electrical impedance and amplitude of the QRS complex were measured at initial implantation and replacement.
Comparison was made between myocardial and endocardial types according to the surface area.
At initial implantation, each patient showed a voltage threshold less than 0.9 volt. The threshold elevated to 2.0 to 2.3 volt at replacement (P<0.001). No significant differences in the increse, however, were seen clinically in types or surface area.
In cases in which a high stimulating threshold was recorded at replacement, the threshold was measured at various pacing pulse width. As the pulse width increased, i.e., amount of electrical energy increased, the threshold voltage decreased. though significant changes in the threshold were uncommon in the chronic stage, a few patients indicated a sudden increase. The fact should be kept in mind seriously in the management of patients with a pacemaker.

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This paper gives the results of stimulation threshold and R-wave sensitivity messurements in 31 patients who received two time PM replacements during the period of October 1975 to August 1978 in our hospital.
The study was made on 31 patients to measured stimulation threshold (bipolar, unipolar), R-wave and impedance.
Usually we have used uJ stimulation threshold by Ohms low.
1.) The 30 patients of bipolar pacing, stimulation thresholds were stabilzed in 12 patients (40%), increased in 12 patients(40%) and decreased 6 patients (20%).
2.) The 16 patients of bipolar and unipolar pacing, R-wave sensitivity were stabilized in 10 patients (62%).
Though the most number of patients has no relation in stimulation threshold and impedance.

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The pacing rate must be controlled on the basis of the clinical condition. The programmable pacemaker is available for this purpose.
Eighty-five patients in our Surgery have undergone implantation of 119 programmable pacemakers (Cordis Omni-Stanicor 162C, D, 190A: 105 generators, Edwards Prolith 215: 4 generators, Intermedics InterLith-RP: 10 generators).
All programming systems have been fully programmed on the basis of hemodynamic examination, clinical condition, or for the reduction of complaints induced by artificial pacing (e. g. palpitation) and for the purpose of carrying out some clinical examination.
No programming trouble or interference has been experienced.

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Experience with 16 pts. with sick sinus syndrome (s. s. s.), aged 17 to 75 years who underwent permanent atrial pacemaker implantation using an atrial pacing catheter electrode were presented.
No A-V conduction disturbance was seen in any of the pts. Six J-shaped electrodes and 10 tined electrodes were utilized. An electrode dislodgement was observed in a case of post cardiac operation because of the elimination of the RA appendage at the time of operation. The remaining 15 pts. have had no trouble in the follow up period of one to 18 months, such as mispacing, dislodgement and an increase in threshold. However missensing of the P-wave was seen in almost half of the pts., because the amplitude of P-wave gained from the atrial electrode was not large enough to be sensed by the conventional demand pacemakers. The competition between the P-wave and atrial pacing, however, was insignificant. The method of atrial pacing dose not require any special techniques and has a very low incidence of failure. We believe that atrial pacing is a treatment of choice for the pts. with s. s. s. not associated with any A-V conduction disturbances.

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Since 1970, six children between age of five months and five years and two adult patients with complete heart block were treated with new type of induction pacemaker. This pacemaker differs in the method of energy transmission from the conventional induction pacemaker, i n which energy of stimulating pulse is continuously transmitted with the use of radiofrequency waves during the interval of stimulating pulses to the heart. The energy is stored in a condensor of the receiver implanted subcutaneously, with which energy transmission from outside of the body is inhibited.
The period of pacing has been 8 years, 7 years, and 5 years respectively without any complication. In four patients, their induction pacemakers were exchanged to other types because of some troubles, mostly fracture of the electrode. Another patient died of hypertrophic myocarditis.
An induction pacemaker is ideal for the treatment of heart block especially in children who need permanent pacing, because of the small sized implant and easy controllability of pacing rate.

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From 1974 to July 1978, 137 pulse generators were implanted in our cardiothoracic department. These included 30 old typed mercury generators (Medtronic 5942, 5945, Cordis Omni-Stanicor), 39 new typed long life mercury generators (Medtronic 5950, 5951, Cordis Stanicor K, Star-Edwards 8116) and 68 lithium pulse generators. In these three groups, the reliability of generators was statiscally analized. Abnormal battery depletions within the expected life length were observed in only one case in the first group and in 13 cases in the second group, whereas no case in the third group. The cummulative survival rate at the end of the expected life length was 95.1% in the first group and 26.1% in the second group.
In conclusion, , it was considered that lithium pulse generators were reliable but new typed mercury pulse generators were not reliable and careful observations were required.

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We have developed a new balancing system for hemofiltration. This system consists of a double chamber roller pump (Pump-1), a bypass roller pump (Pump-2), negative pressure pump (Pump-3) and filter. Principle of this system is to equalyze arterial blood flow from the patient to venous blood flow to the patient. A whole system must be closed circuit. When ultrafiltrate was withdown through the filter by Pump-3, blood volume in this system must be replaced from outside. This should be automatically done with substitutionfluid. Accordingly, an identical infusion rate of substitutionfluid with ultrafiltration rate is delivered to the venous line distal to the filter. Extra-rultrafiltrate (Body weightloss) can be obtained by bypassing venous blood flow from the distal to the proximal to pump-1, allowing precise body weightloss by pre-setting Pump-2. Erythrocyte fragility was compared between conventional hemodialysis and hemofiltration by this system. There was no difference in erythrocyte fragility between hemodialysis and hemofiltration.

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The clinical demands for filters of hemofiltration were estimated by comparison of normal urinary excretion, f filtrate volume and solute concentrations in filtrate. Ultrafiltration rate more than 76ml/min (blood flow rate 200ml/min is required for sufficient extraction of small molecular substances. Only three of currently available thirteen hollow-fiber filters examined clinically satisfied this requirement. These were the ones made of polyacrylonitrile membrane. Theoretical and empirical equations of ultrafiltration rate were estimated and Yoshida's equation showed best corelation to the clinical results.

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