PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Heart, Artificial”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1978

Total support of the circulation of a patient with post-cardiotomy stone-heart syndrome by a partial artificial heart (ALVAD) for 5 days followed by heart and kidney transplantation.

A patient with acute bacterial endocarditis in whom ischaemic contracture of the left ventricle (stone-heart syndrome) developed during aortic and mitral valve replacement had an emergency implantation of an intracorporeal partial artificial heart (an abdominal left-ventricular assist device of ALVAD). This device functioned as a total artificial heart for nearly 6 days, while a donor heart for transplantation was sought. The ALVAD was then removed, and the patient received allografts of a heart and a kidney. The transplanted heart functioned well, but the patient died 15 days later from gram-negative sepsis. There was no evidence of cardiac or renal allograft rejection.

Acute Disease↗
PubMed1978

Paracorporeal artificial heart in postoperative heart failure.

A pneumatically driven artificial heart with a tubular silicone rubber membrane and disc valves was used for functional heart replacement in the paracorporeal mode. A fluidic drive system allows adjustment of the heart rate, positive and negative pressures and systole/diastole ratio. Since August, 1977, the artificial heart has been used in four patients with refractory postoperative heart failure not responding to volume loading, pH and electrolyte correction, catecholamines and intra-aortic balloon pumping. Large cannulae were placed in the atria and great vessels. The ventricles were fixed on the chest paracorporeally. The assist system was used as a left heart bypass in one patient and as a biventricular bypass in three other patients. After 48-72 hours, the ventricular function recovered in three patients, permitting removal of the artificial heart. One patient died of cerebral complications six weeks later; the other two recovered completely and were released in good condition. Profound postoperative heart failure can be completely reversed by the use of the paracorporeal artificial heart; the advantage of the system lies in the simplicity of its implantation and removal.

Adolescent↗
PubMed1979

Six-month survival of a calf with an artificial heart.

A pneumatically powered artificial heart, constructed primarily from a polyurethane, was implanted in the chest of a calf and supported the calf for more than 6 months. The heart, which was designed to fit in the chest of a 90 kilogram calf, was able to suppor the animal when it weighed 180 kilograms. During the first 105 days the calf remained strong and healthy. The animal grew progressively weaker after day 106, and by day 160 right heart failure became apparent. The principal cause of the right heart failure was an obstructive growth between the right atrium and the right ventricle. An attempt to correct the problem on day 184 with an artificial heart resulted in the animal's death.

Animals↗
PubMed1975

Survival for 18 days with a Jarvik-type artificial heart.

This is a report of an experiment wherein a calf had its natural heart replaced with an artificial heart and survived for 18 days and 20 hours. All measured physiologic parameters remained normal until the fourteenth day. Thereafter a gradual persistent rise in venous pressure and signs of a decreased cardiac output occurred. However, the animal outwardly appeared normal until the eighteenth day. During the nineteenth day it became comatose and was killed. At autopsy large thrombi were found in both atria, impairing ventricular filling, resulting in venous congestion and diminished cardiac output. This extended survival time and our ability to understand and eliminate the problems associated with artificial heart implantation give support to our hope that artificial hearts for man will be possible in the not too distant future.

Acute Kidney Injury↗
PubMedDate not supplied

The role of cardiac valves in artificial heart performance.

The criteria for the design, selection of materials, and fabrication of a total artificial heart have evolved over several years. As these criteria have become more sophisticated and exact, they have optimized the performance of all components within the system. A pump with sufficient volume and pressure output that fits in the available anatomic space was a primary objective. Concomitantly, a nonthrombogenic, durable material that was nondegradable in body fluids was being developed. The most easily managed energy source selected to date has been pulsed, compressed air programmed for gentle but effective systole and diastole. The evolution of good cardiac valves has been of major importance to the artificial heart effort. The historical development of the artificial heart has often centered around existing prosthetic valves which are currently an integral component of the complete system. A detailed analysis of the performance of the total artificial heart clearly identifies the role of the cardiac valve.

Animals↗
PubMedDate not supplied

[Comparative study of different artificial heart designs].

The results subsequent to investigations of 3 artificial heart constructions effected on a hydrodynamic stand are reported. The values of the artificial heart resistances during the systole and diastole were determined, these being shown to stand close to one another in all of the designs under review.

Evaluation Studies as Topic↗
PubMed1977

Implantation of the total artificial heart by lateral thoracotomy.

Progress in the techniques for surgical implantation of the artificial heart has progressed in parallel with the technology and design of the prosthesis. In the author's first experience with total artificial heart (TAH) implantation (1968) a trans-sternal split was used opening the sixth intercostal space on the right side across the sternum to the left space. This obviously was not the optimum approach but the complexity, design and size of the prosthesis required maximum exposure of the atria and great vessels. Subsequently the mid-sternal split incision was used. The Dacron fibril coated silicone rubber 8 cm Kwan-Gett ventricles implanted by the mid-sternal split sustained a calf for 14 days in 1972. A calf with the improved Jarvik 3 ventricles fabricated with the same material and implanted via mid-sternal split survived 19 days in early 1973. The surgical techniques for lateral (right) thoracotomy were adopted in this laboratory in 1973. These techniques were applicable only when the prosthesis fit better in the chest. This procedure has been adopted by other laboratories replacing the natural heart of the calf with a TAH. This report describes in detail the stepwise procedure for implantation of the total artificial heart by a lateral thoracotomy in the calf.

Animals↗
PubMed1978

Partial artificial heart (ALVAD) use with subsequent cardiac and renal allografting in a patient with stone heart syndrome.

The abdominal left ventricular assist device (ALVAD) is an order of magnitude more effective than conventional intra-aortic balloon pumping (IABP) in unloading and providing circulatory support to the failing left ventricle. This is a report of a unique case which demonstrates that in the absence of pulmonary vascular obstruction or constriction, the ALVAD can substitute for both left and right heart function. A 21-year-old patient with a congenital bicuspid aortic valve developed acute valvular endocarditis which rapidly progressed to congestive heart failure. An operation was undertaken, the mitral and aortic valves were excised and replaced by porcine heterografts, and a fistula from the right sinus of Valsalva to the right ventricle was closed. When coronary circulation was restored, irreversible ischemic contracture of the left ventricle, or "stone heart" syndrome, developed and emergency ALVAD or partial artificial heart implantation was effected. This device functioned as a total artificial heart for nearly six days, while a donor heart was sought. The patient then underwent removal of the ALVAD and cardiac and renal allografting. The transplanted heart functioned well, but the patient expired fifteen days later from gram-negative sepsis.

Adult↗
PubMedDate not supplied

[Method of bench testing an artificial heart].

A procedure for bench trials of the artificial heart (AH), that comes to determining the relationship between the AH performance and the duration of the systole with constant pressure differentials at the in- and outlets of the AH and pulse rate. The results of the AH trials by the proposed procedure are described.

Heart, Artificial↗
PubMed1977

Survival for 145 days with a total artificial heart.

A calf into which a biolized, total artificial heart (TAH) had been implanted survived for 145 days. All measured physiological parameters except central venous pressure (CVP) were back to normal one month after implantation, and thereafter the animal's physiological development was similar to that of a normal calf. The intimal weight, which was 96 kilograms at implantation, reached 190 kilogram at the end of experiment, with a daily gain rate of 0.9 kilogram per day. After the nineteenth postoperative week, signs of congestive heart failure appeared, such as high venous pressure, ascites, and enlarged liver although the calf outwardly appeared well. On postoperative day 146, the animal started foaming at the mouth, and a convulsion occurred; then, the experiment was terminated after 3,494 hours of pumping. At autopsy, there were acute bilateral bronchopneumonia involving mostly both upper lobes, pulmonary edema, slight chronic pneumonitis, and hepatomegaly. There were no serious thrombotic deposits inside the cardiac prosthesis.

Animals↗
PubMed1978

Comparison of cardiovascular responses and left ventricular work during exercise before and after artificial heart implantation.

Cardiovascular dynamics and left ventricular work were evaluated in 15 resting, standing, and treadmill-exercised calves before and at periodic intervals after their natural hearts (NH) were replaced with an artificial heart (AH). Standing produced increases in heart rate, cardiac output, oxygen uptake, and left ventricular work and decreases in mean aortic pressure and systemic vascular resistance in NH calves which were more marked with exercise. AH calves had higher aortic pressures, cardiac output, systemic vascular resistance, oxygen uptake, and left ventricular work during resting conditions in the first 2 postoperative weeks than did NH calves, which gradually returned to values similar to the latter by the fifth week after operation. Exercise was not tolerated early after AH implantation, but was after 5 to 6 weeks. Our results indicate that AH calves increase cardiac output with exercise by reducing systemic vascular resistance, whereas NH animals respond similarly, but also increase heart rate. The data suggest that a marked elevation in systemic vascular resistance early after AH implantation increases left ventricular work and prevents adequate rises in cardiac output to all but minor increases in metabolic requirements.

Animals↗
PubMed1978

Scanning electron microscopic evaluation of the surfaces of artificial hearts.

This report summarizes the surface changes seen in artificial hearts implanted in calves for periods up to four months. Fabrication defects as well as degradation resulting from wear are identified. SEM evaluation of the blood contacting surface as well as the surface of the diaphragm associated with the drive mechanisms has revealed potential problems with current heart designs and methods of fabrication. Materials evaluation of implanted hearts is crucial for a clinically useful system to evolve.

Animals↗
PubMedDate not supplied

[Artificial heart control system].

To develop a system for the artificial heart control the algorhythm of the latter, with the blood pressure in the aorta acting as a regulation parameter, was analyzed on its mathematical model. The results of the algorhythm operation in three model situation describing transitional processes under physical efforts, stress and resuscitation are reported. The technical implemetation of the described algorhythm is set forth and a comparison of the obtained experimental data versus the design curves is made.

Aorta↗