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Sample records for artificial heart devices

  1. High reliability linear drive device for artificial hearts

    NASA Astrophysics Data System (ADS)

    Ji, Jinghua; Zhao, Wenxiang; Liu, Guohai; Shen, Yue; Wang, Fangqun

    2012-04-01

    In this paper, a new high reliability linear drive device, termed as stator-permanent-magnet tubular oscillating actuator (SPM-TOA), is proposed for artificial hearts (AHs). The key is to incorporate the concept of two independent phases into this linear AH device, hence achieving high reliability operation. The fault-tolerant teeth are employed to provide the desired decoupling phases in magnetic circuit. Also, as the magnets and the coils are located in the stator, the proposed SPM-TOA takes the definite advantages of robust mover and direct-drive capability. By using the time-stepping finite element method, the electromagnetic characteristics of the proposed SPM-TOA are analyzed, including magnetic field distributions, flux linkages, back- electromotive forces (back-EMFs) self- and mutual inductances, as well as cogging and thrust forces. The results confirm that the proposed SPM-TOA meets the dimension, weight, and force requirements of the AH drive device.

  2. Fatal Acanthamoeba Encephalitis in a Patient With a Total Artificial Heart (Syncardia) Device

    PubMed Central

    Tan, Susanna K.; Gajurel, Kiran; Tung, Christie; Albers, Gregory; Deresinski, Stan; Montoya, Jose G.; Sheikh, Ahmad Y.; Banerjee, Dipanjan; Ha, Richard

    2014-01-01

    Acanthamoeba encephalitis is an uncommon but often fatal infection complication. Here we report the first case of Acanthamoeba encephalitis in a patient with a Total Artificial Heart device. PMID:25734127

  3. The total artificial heart

    PubMed Central

    Cook, Jason A.; Shah, Keyur B.; Quader, Mohammed A.; Cooke, Richard H.; Kasirajan, Vigneshwar; Rao, Kris K.; Smallfield, Melissa C.; Tchoukina, Inna

    2015-01-01

    The total artificial heart (TAH) is a form of mechanical circulatory support in which the patient’s native ventricles and valves are explanted and replaced by a pneumatically powered artificial heart. Currently, the TAH is approved for use in end-stage biventricular heart failure as a bridge to heart transplantation. However, with an increasing global burden of cardiovascular disease and congestive heart failure, the number of patients with end-stage heart failure awaiting heart transplantation now far exceeds the number of available hearts. As a result, the use of mechanical circulatory support, including the TAH and left ventricular assist device (LVAD), is growing exponentially. The LVAD is already widely used as destination therapy, and destination therapy for the TAH is under investigation. While most patients requiring mechanical circulatory support are effectively treated with LVADs, there is a subset of patients with concurrent right ventricular failure or major structural barriers to LVAD placement in whom TAH may be more appropriate. The history, indications, surgical implantation, post device management, outcomes, complications, and future direction of the TAH are discussed in this review. PMID:26793338

  4. Wearable air supply for pneumatic artificial hearts and ventricular assist devices.

    PubMed

    Sipin, A J; Fabrey, W J; Smith, S H; Doussourd, J D; Olsen, D B

    1992-08-01

    An experimental wearable air supply for pneumatic artificial hearts and ventricular assist devices has been built and tested. The unit eliminates the need for tethering to a large, stationery driver. The miniaturized air supply is designed for ambulatory patients with implanted pulsatile pneumatic total artificial hearts (TAH) or pneumatic left-ventricular assist devices (LVAD), to permit mobility in clinical and home settings. The device has major short-term utility as a supply for pneumatic TAH or VAD bridges in patients awaiting heart transplants. The system design for the wearable driver includes a novel, fast rotary compressor, driven by a brushless direct current (DC) motor to supply air to the ventricle through an electromagnetically actuated directional valve, all controlled by a microcomputer. Stroke volume from 0 to 200 cc; pulse rate from 60 to 160 bpm, and duty cycle from 33% to 50% are selected on a keyboard, and the selected or measured parameters can be shown on a liquid crystal display. For control of delivery from a single ventricular assist device, stroke volume is controlled by variation of compressor speed. In the wearable air supply for a TAH, a single compressor drives both ventricles alternately through a double-acting directional valve. Air volume delivered to the left ventricle is adjusted by variation of compressor speed, and air volume to the right ventricle by variation of ejection time. The effect on blood flow rate of the lower impedance to the right ventricle is compensated by provision of a two-stage compressor, in which a single stage drives the right ventricle, and both stages connected in parallel drive the left ventricle. The overall dimensions of the prototype air supply for driving either a TAH or LVAD are 4.5 by 7.8 by 4.5 inches, including an emergency battery with a duration of 15 to 30 min depending on load. The weight is presently 5.5 lb, but this will be reduced in a production design and for a dedicated LVAD air supply

  5. Artificial heart for humanoid robot

    NASA Astrophysics Data System (ADS)

    Potnuru, Akshay; Wu, Lianjun; Tadesse, Yonas

    2014-03-01

    A soft robotic device inspired by the pumping action of a biological heart is presented in this study. Developing artificial heart to a humanoid robot enables us to make a better biomedical device for ultimate use in humans. As technology continues to become more advanced, the methods in which we implement high performance and biomimetic artificial organs is getting nearer each day. In this paper, we present the design and development of a soft artificial heart that can be used in a humanoid robot and simulate the functions of a human heart using shape memory alloy technology. The robotic heart is designed to pump a blood-like fluid to parts of the robot such as the face to simulate someone blushing or when someone is angry by the use of elastomeric substrates and certain features for the transport of fluids.

  6. Multi-Targeted Antithrombotic Therapy for Total Artificial Heart Device Patients

    PubMed Central

    Ramirez, Angeleah; Riley, Jeffrey B.; Joyce, Lyle D.

    2016-01-01

    Abstract: To prevent thrombotic or bleeding events in patients receiving a total artificial heart (TAH), agents have been used to avoid adverse events. The purpose of this article is to outline the adoption and results of a multi-targeted antithrombotic clinical procedure guideline (CPG) for TAH patients. Based on literature review of TAH anticoagulation and multiple case series, a CPG was designed to prescribe the use of multiple pharmacological agents. Total blood loss, Thromboelastograph® (TEG), and platelet light-transmission aggregometry (LTA) measurements were conducted on 13 TAH patients during the first 2 weeks of support in our institution. Target values and actual medians for postimplant days 1, 3, 7, and 14 were calculated for kaolinheparinase TEG, kaolin TEG, LTA, and estimated blood loss. Protocol guidelines were followed and anticoagulation management reduced bleeding and prevented thrombus formation as well as thromboembolic events in TAH patients postimplantation. The patients in this study were susceptible to a variety of possible complications such as mechanical device issues, thrombotic events, infection, and bleeding. Among them all it was clear that patients were at most risk for bleeding, particularly on postoperative days 1 through 3. However, bleeding was reduced into postoperative days 3 and 7, indicating that acceptable hemostasis was achieved with the anticoagulation protocol. The multidisciplinary, multi-targeted anticoagulation clinical procedure guideline was successful to maintain adequate antithrombotic therapy for TAH patients. PMID:27134306

  7. Multi-Targeted Antithrombotic Therapy for Total Artificial Heart Device Patients.

    PubMed

    Ramirez, Angeleah; Riley, Jeffrey B; Joyce, Lyle D

    2016-03-01

    To prevent thrombotic or bleeding events in patients receiving a total artificial heart (TAH), agents have been used to avoid adverse events. The purpose of this article is to outline the adoption and results of a multi-targeted antithrombotic clinical procedure guideline (CPG) for TAH patients. Based on literature review of TAH anticoagulation and multiple case series, a CPG was designed to prescribe the use of multiple pharmacological agents. Total blood loss, Thromboelastograph(®) (TEG), and platelet light-transmission aggregometry (LTA) measurements were conducted on 13 TAH patients during the first 2 weeks of support in our institution. Target values and actual medians for postimplant days 1, 3, 7, and 14 were calculated for kaolinheparinase TEG, kaolin TEG, LTA, and estimated blood loss. Protocol guidelines were followed and anticoagulation management reduced bleeding and prevented thrombus formation as well as thromboembolic events in TAH patients postimplantation. The patients in this study were susceptible to a variety of possible complications such as mechanical device issues, thrombotic events, infection, and bleeding. Among them all it was clear that patients were at most risk for bleeding, particularly on postoperative days 1 through 3. However, bleeding was reduced into postoperative days 3 and 7, indicating that acceptable hemostasis was achieved with the anticoagulation protocol. The multidisciplinary, multi-targeted anticoagulation clinical procedure guideline was successful to maintain adequate antithrombotic therapy for TAH patients.

  8. Totally implantable total artificial heart and ventricular assist device with multipurpose miniature electromechanical energy system.

    PubMed

    Takatani, S; Orime, Y; Tasai, K; Ohara, Y; Naito, K; Mizuguchi, K; Makinouchi, K; Damm, G; Glueck, J; Ling, J

    1994-01-01

    A multipurpose miniature electromechanical energy system has been developed to yield a compact, efficient, durable, and biocompatible total artificial heart (TAH) and ventricular assist device (VAD). Associated controller-driver electronics were recently miniaturized and converted into hybrid circuits. The hybrid controller consists of a microprocessor and controller, motor driver, Hall sensor, and commutation circuit hybrids. The sizing study demonstrated that all these components can be incorporated in the pumping unit of the TAH and VAD, particularly in the centerpiece of the TAH and the motor housing of the VAD. Both TAH and VAD pumping units will start when their power line is connected to either the internal power pack or the external battery unit. As a redundant driving and diagnostic port, an emergency port was newly added and will be placed in subcutaneous location. In case of system failure, the skin will be cut down, and an external motor drive or a pneumatic driver will be connected to this port to run the TAH. This will minimize the circulatory arrest time. Overall efficiency of the TAH without the transcutaneous energy transmission system was 14-18% to deliver pump outputs of 4-9 L/min against the right and left afterload pressures of 25 and 100 mm Hg. The internal power requirement ranged from 6 to 13 W. The rechargeable batteries such as NiCd or NiMH with 1 AH capacity can run the TAH for 30-45 min. The external power requirement, when TETS efficiency of 75% was assumed, ranged from 8 to 18 W. The accelerated endurance test in the 42 degrees C saline bath demonstrated stable performance over 4 months. Long-term endurance and chronic animal studies will continue toward a system with 5 years durability by the year 2000.

  9. Totally implantable artificial hearts and left ventricular assist devices: selecting impermeable polycarbonate urethane to manufacture ventricles.

    PubMed

    Yang, M; Zhang, Z; Hahn, C; Laroche, G; King, M W; Guidoin, R

    1999-01-01

    In the development of a new generation of totally implantable artificial hearts and left ventricular assist devices (VADs) for long-term use, the selection of an acceptable material for the fabrication of the ventricles probably represents one of the greatest challenges. Segmented polyether urethanes used to be the material of choice due to their superior flexural performance, acceptable blood compatibility, and ease of processing. However, because they are known to degrade and to be readily permeable to water, they cannot meet the rigorous requirements needed for a new generation of implantable artificial hearts and VADs. Therefore, the objective of the present study was to identify alternative polymeric materials that would be satisfactory for fabricating the ventricles, and in particular, to determine the water permeability through membranes made from four commercial polycarbonate urethanes (Carbothane PC3570A, Chronoflex AR, Corethane 80A, and Corethane 55D) in comparison to those made from two traditional polyether urethanes (Tecoflex EG80A and Tecothane TT-1074A). In addition to determining the rate of water transmission through the six membranes by exposing them to deionized water, saline, and albumin-Krebs solution under pressure and measuring the displacement of liquid by means of a recently developed capillary method, the inherent surface and chemical properties of the six membranes were characterized by SEM, contact angle measurements, FTIR, DSC, and GPC techniques. The results of the study demonstrated that the rate of water transmission through the four polycarbonate urethane membranes was significantly lower than through the two polyether urethanes. In fact the lowest values were recorded with the two Corethane membranes, and the harder type 55D polymer had a lower value (2.7 x 10(-7) g/s cm2) than the softer 80A version (3.3 x 10(-7) g/s cm2). This level of water vapor permeability, which appears to be controlled primarily by a Fickian diffusion

  10. Totally implantable artificial hearts and left ventricular assist devices: selecting impermeable polycarbonate urethane to manufacture ventricles.

    PubMed

    Yang, M; Zhang, Z; Hahn, C; Laroche, G; King, M W; Guidoin, R

    1999-01-01

    In the development of a new generation of totally implantable artificial hearts and left ventricular assist devices (VADs) for long-term use, the selection of an acceptable material for the fabrication of the ventricles probably represents one of the greatest challenges. Segmented polyether urethanes used to be the material of choice due to their superior flexural performance, acceptable blood compatibility, and ease of processing. However, because they are known to degrade and to be readily permeable to water, they cannot meet the rigorous requirements needed for a new generation of implantable artificial hearts and VADs. Therefore, the objective of the present study was to identify alternative polymeric materials that would be satisfactory for fabricating the ventricles, and in particular, to determine the water permeability through membranes made from four commercial polycarbonate urethanes (Carbothane PC3570A, Chronoflex AR, Corethane 80A, and Corethane 55D) in comparison to those made from two traditional polyether urethanes (Tecoflex EG80A and Tecothane TT-1074A). In addition to determining the rate of water transmission through the six membranes by exposing them to deionized water, saline, and albumin-Krebs solution under pressure and measuring the displacement of liquid by means of a recently developed capillary method, the inherent surface and chemical properties of the six membranes were characterized by SEM, contact angle measurements, FTIR, DSC, and GPC techniques. The results of the study demonstrated that the rate of water transmission through the four polycarbonate urethane membranes was significantly lower than through the two polyether urethanes. In fact the lowest values were recorded with the two Corethane membranes, and the harder type 55D polymer had a lower value (2.7 x 10(-7) g/s cm2) than the softer 80A version (3.3 x 10(-7) g/s cm2). This level of water vapor permeability, which appears to be controlled primarily by a Fickian diffusion

  11. Computation of incompressible viscous flows through artificial heart devices with moving boundaries

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin; Rogers, Stuart; Kwak, Dochan; Chang, I.-DEE

    1991-01-01

    The extension of computational fluid dynamics techniques to artificial heart flow simulations is illustrated. Unsteady incompressible Navier-Stokes equations written in 3-D generalized curvilinear coordinates are solved iteratively at each physical time step until the incompressibility condition is satisfied. The solution method is based on the pseudo compressibility approach and uses an implicit upwind differencing scheme together with the Gauss-Seidel line relaxation method. The efficiency and robustness of the time accurate formulation of the algorithm are tested by computing the flow through model geometries. A channel flow with a moving indentation is computed and validated with experimental measurements and other numerical solutions. In order to handle the geometric complexity and the moving boundary problems, a zonal method and an overlapping grid embedding scheme are used, respectively. Steady state solutions for the flow through a tilting disk heart valve was compared against experimental measurements. Good agreement was obtained. The flow computation during the valve opening and closing is carried out to illustrate the moving boundary capability.

  12. An electric artificial heart for clinical use.

    PubMed

    Pierce, W S; Rosenberg, G; Snyder, A J; Pae, W E; Donachy, J H; Waldhausen, J A

    1990-09-01

    Advances in microelectronics, high-strength magnets, and control system design now make replacement of the heart using an implantable, electrically powered pump feasible. The device described herein is a compact, dual pusher plate unit with valved polyurethane sac-type ventricles positioned at either end. The power unit consists of a small, brushless direct current motor and a motion translator. A microprocessor control system is used to regulate heart beat rate and provide left-right output balance. Bench studies lasting for as long as 1 year have been performed. Heart replacement with the electric heart has been performed in 18 calves since 1984. The longest survivor lived for more than 7 months. Among the causes of termination were component failure, thromboembolic complications, and bleeding. No major problem has been identified that precludes prolonged use of the electric heart. In the future the patient with end-stage heart disease will have an electric artificial heart as one therapeutic option.

  13. Therapeutic and physiological artificial heart: future prospects.

    PubMed

    Nosé, Y; Ohtsubo, S; Tayama, E

    1997-07-01

    Current left ventricular assist devices (LVADs) have demonstrated admirable results. However, approximately one-fourth of the patients who require LVADs suffer from right heart failure and require additional right ventricular (RV) assist devices (RVADs). The RV failure impairs the splanchnic circulation, subsequently developing into multiorgan failure (MOF). An aggressive application of a biventricular assist device (BVAD) is the best way to avoid and treat MOF because the BVAD reduces splanchnic congestion. Also, because the BVAD allows retention of the natural heart, recovery of the heart function can be expected after long-term assist. This benefit cannot be expected from conventional total artificial hearts. Although there are no implantable clinical BVAD systems in existence today, present advanced technologies in rotary blood pumps can enable these systems to be totally implantable. So, we should focus on developing a totally implantable BVAD system. The implantable BVAD will be a therapeutic and physiological total artificial heart, and it will be a common home health care device in the near future. PMID:9212923

  14. Ethical challenges with deactivation of durable mechanical circulatory support at the end of life: left ventricular assist devices and total artificial hearts.

    PubMed

    Rady, Mohamed Y; Verheijde, Joseph L

    2014-01-01

    Left ventricular assist devices (LVADs) and total artificial hearts (TAHs) are surgically implanted as permanent treatment of unrecoverable heart failure. Both LVADs and TAHs are durable mechanical circulatory support (MCS) devices that can prolong patient survival but also alter end-of-life trajectory. The permissibility of discontinuing assisted circulation is controversial because device deactivation is a life-ending intervention. Durable MCS is intended to successfully replace native physiological functions in heart disease. We posit that the presence of new lethal pathophysiology (ie, a self-perpetuating cascade of abnormal physiological processes causing death) is a central element in evaluating the permissibility of deactivating an LVAD or a TAH. Consensual discontinuation of durable MCS is equivalent with allowing natural death when there is an onset of new lethal pathophysiology that is unrelated to the physiological functions replaced by an LVAD or a TAH. Examples of such lethal conditions include irreversible coma, circulatory shock, overwhelming infections, multiple organ failure, refractory hypoxia, or catastrophic device failure. In all other situations, deactivating the LVAD/TAH is itself the lethal pathophysiology and the proximate cause of death. We postulate that the onset of new lethal pathophysiology is the determinant factor in judging the permissibility of the life-ending discontinuation of a durable MCS.

  15. Artificial Heart Fluid Dynamics.

    NASA Astrophysics Data System (ADS)

    Mussivand, Tofigh Varcaneh

    Flow characteristics within pneumatic, pulsatile, and pusher plate prosthetic hearts were studied. The blood pumps evaluated were duplicates of pumps used for in vivo calf and for clinical implantation at the Cleveland Clinic Foundation. Human dura mater bioprosthetic, caged disk, and Bjork-Shiley tilting disk valves were employed in the pumps. Dual camera video tape and synchronized still photography were used to study flow patterns. Diffused light and a planar laser source provided illumination. The laser light was fanned into a plane with a thickness of 0.2 mm to 10 mm. Magnesium oxide and Amberlite particles were used as tracers. Aqueous-glycerol, aqueous-sucrose solutions and mineral oil were used as blood analog fluids. Inflow, outflow, drive, and afterload pressures, diaphragm motion, cardiac output, and heart rate were measured and recorded. An electrical circuit was developed to synchronize pump diaphragm motion with captured images of flow trajectories. After digitizing the trajectories, velocities, global and local turbulence, and shear stresses were obtained. Disturbed and recirculating zones were identified. Qualitative and quantitative analyses were performed using data obtained from the digitization of flow trajectories. Simultaneous turbulence and stasis were observed during most phases of the cardiac cycles in all the pumps tested. A maximum Reynold's shear stress of 2889 dynes/cm ^2 occurred at 120 beats per minute (bpm). The peak velocity was 146 cm/sec during systole. The identified regions of recirculation, low velocity and disturbed flow were shown to correlate with thrombosed areas of explanted blood pumps. The maximum calculated turbulence intensity was 106 cm/sec which occurred at 120 bpm during systole.

  16. SynCardia: the total artificial heart

    PubMed Central

    Anyanwu, Anelechi; Zucchetta, Fabio; Gerosa, Gino

    2014-01-01

    The SynCardia total artificial heart (TAH) currently provides the most definitive option for patients with biventricular failure who are not candidates for isolated left ventricular (LV) assist device placement. The techniques for implantation are adaptable to almost all patients with advanced heart failure, including those with severe biventricular cardiomyopathy, complex congenital heart disease, failed LV assist devices, failed transplantations, and acquired structural heart defects that have failed or are not amenable to conventional surgical treatment. Over the years, the implantation technique has evolved in order to minimize the surgical invasiveness of the procedure, in anticipation of additional future surgery. Meticulous hemostasis with double layer sutures, use of Gore-Tex sheets around the TAH and the pericardial cavity, and use of tissue expanders to avoid contraction of pericardial cavity around the device are discussed in detail in the following report. Additionally, we will provide our experience with implantation of TAH in various challenging scenarios, such as patients with a small chest cavity, congenital heart defects, and simultaneous use of extracorporeal membrane oxygenation (ECMO). PMID:25512904

  17. Actuator device for artificial leg

    NASA Technical Reports Server (NTRS)

    Burch, J. L. (Inventor)

    1976-01-01

    An actuator device is described for moving an artificial leg of a person having a prosthesis replacing an entire leg and hip joint. The device includes a first articulated hip joint assembly carried by the natural leg and a second articulated hip joint assembly carried by the prosthesis whereby energy from the movement of the natural leg is transferred by a compressible fluid from the first hip joint assembly to the second hip joint assembly for moving the artificial leg.

  18. Computed Flow Through An Artificial Heart Valve

    NASA Technical Reports Server (NTRS)

    Rogers, Stewart E.; Kwak, Dochan; Kiris, Cetin; Chang, I-Dee

    1994-01-01

    Report discusses computations of blood flow through prosthetic tilting disk valve. Computational procedure developed in simulation used to design better artificial hearts and valves by reducing or eliminating following adverse flow characteristics: large pressure losses, which prevent hearts from working efficiently; separated and secondary flows, which causes clotting; and high turbulent shear stresses, which damages red blood cells. Report reiterates and expands upon part of NASA technical memorandum "Computed Flow Through an Artificial Heart and Valve" (ARC-12983). Also based partly on research described in "Numerical Simulation of Flow Through an Artificial Heart" (ARC-12478).

  19. Atrial septum defect closure device in a beating heart, from the perspective of a researcher in artificial organs.

    PubMed

    Tomizawa, Yasuko

    2012-12-01

    Transcatheter closure of atrial septum defect (ASD) with a closure device is increasing, but the history of clinical use of this procedure is still short, and the efficacy and long-term safety remain unproved. The total number of closure devices implanted throughout the world has not been counted accurately. Therefore, the probability of complications occurring after implantation is uncertain. Device-related complications that occur suddenly late after implantation are life-threatening, and quite often necessitate emergency surgical intervention. In Japanese medical journals, authors reporting closure devices have mentioned no complications and problems in their facilities. Detailed studies of device-related complications and device removal have not been reported in Japan. In fact, this literature search found an unexpectedly large number of reports of various adverse events from many overseas countries. When follow-up duration is short and the number of patients is small, the incidence of complications cannot be determined. Rare complications may emerge in a large series with a long observation period. Consequently, the actual number of incidents related to ASD closure devices is possibly several times higher than the number reported. Guidelines for long-term patient management for patients with an implanted closure device are necessary and post-marketing surveillance is appropriate. Development of a national database, a worldwide registration system, and continuous information disclosure will improve the quality of treatment. The devices currently available are not ideal in view of reports of late complications requiring urgent surgery and the need for life-long follow-up. An ideal device should be free from complications during life, and reliability is indispensable.

  20. Anaerobic threshold in total artificial heart animals.

    PubMed

    Chiang, B Y; Pantalos, G; Burns, G L; Long, J W; Khanwilkar, P S; Everett, S D; Mohammad, S F; Olsen, D B

    1994-01-01

    The anaerobic threshold represents an objective measure of functional capacity and is useful in assessment of pulmonary and cardiovascular dysfunction. This study determined the anaerobic threshold in total artificial heart animals and evaluated the performance of the total artificial heart system. Five animals with total artificial hearts were put under incremental exercise testing after exercise training. The intensity of exercise ranged from 2.0 to 4.5 km/hr, with an increment of 0.5 km/hr every 3 min. The anaerobic threshold was 6.72 +/- 0.84 ml/kg/min as detected by the lactate method, and 6.48 +/- 0.79 by the CO2 method. The value of the anaerobic threshold in total artificial heart animals implies that the performance capacity of a total artificial heart is not sufficient to meet the oxygen requirements of vigorously exercising skeletal muscle. The protocol does not allow for driving parameter changes during exercise, and this situation, combined with the manual mode of the control system used, was inadequate to allow the total artificial heart animals to exercise more vigorously. Using an automatic control mode might be helpful, as well as considering the relationship between indices of oxygen metabolism, such as oxygen delivery, oxygen consumption, and oxygen extraction rate, in the control algorithms in total artificial heart control systems.

  1. What Is a Total Artificial Heart?

    MedlinePlus

    ... that the CardioWest is connected to an outside power source and the AbioCor isn't. The CardioWest ... run from inside the chest to an outside power source. Normal Heart and CardioWest Total Artificial Heart ...

  2. FLUID MECHANICS OF ARTIFICIAL HEART VALVES

    PubMed Central

    Dasi, Lakshmi P; Simon, Helene A; Sucosky, Philippe; Yoganathan, Ajit P

    2009-01-01

    SUMMARY 1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird’s-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10–15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage. PMID:19220329

  3. Implanted artificial heart with radioisotope power source.

    PubMed

    Shumakov, V I; Griaznov, G M; Zhemchuzhnikov, G N; Kiselev, I M; Osipov, A P

    1983-02-01

    An atomic artificial heart for orthotopic implantation was developed with the following characteristics: volume, 1.2 L; weight, 1.5 kg; radioisotope power, 45 W; operating life, up to 5 years; hemodynamics, similar to natural hemodynamics. The artificial heart includes a thermal drive with systems for regulating power, feeding steam into the cylinders, return of the condensate to the steam generator, and delivery of power to the ventricles and heat container. The artificial heart is placed in an artificial pericardium partially filled with physiologic solution. It uses a steam engine with two operating cylinders that separately drive the left and right ventricles. There is no electronic control system in the proposed design. The operation of the heat engine is controlled, with preservation of autoregulation by the vascular system of the body. The separate drives for the ventricles is of primary importance as it provides for operation of the artificial heart through control of cardiac activity by venous return. Experimental testing on a hydromechanical bench demonstrated effective autoregulation.

  4. Implanted artificial heart with radioisotope power source.

    PubMed

    Shumakov, V I; Griaznov, G M; Zhemchuzhnikov, G N; Kiselev, I M; Osipov, A P

    1983-02-01

    An atomic artificial heart for orthotopic implantation was developed with the following characteristics: volume, 1.2 L; weight, 1.5 kg; radioisotope power, 45 W; operating life, up to 5 years; hemodynamics, similar to natural hemodynamics. The artificial heart includes a thermal drive with systems for regulating power, feeding steam into the cylinders, return of the condensate to the steam generator, and delivery of power to the ventricles and heat container. The artificial heart is placed in an artificial pericardium partially filled with physiologic solution. It uses a steam engine with two operating cylinders that separately drive the left and right ventricles. There is no electronic control system in the proposed design. The operation of the heat engine is controlled, with preservation of autoregulation by the vascular system of the body. The separate drives for the ventricles is of primary importance as it provides for operation of the artificial heart through control of cardiac activity by venous return. Experimental testing on a hydromechanical bench demonstrated effective autoregulation. PMID:6838394

  5. THEORETICAL DESIGN CONSIDERATIONS AND PHYSIOLOGIC PERFORMANCE CRITERIA FOR AN IMPROVED INTRACORPOREAL (ABDOMINAL) ELECTRICALLY ACTUATED LONG-TERM LEFT VENTRICULAR ASSIST DEVICE (“E-TYPE” ALVAD) OR PARTIAL ARTIFICIAL HEART

    PubMed Central

    Igo, Stephen R.; Hibbs, C. Wayne; Fuqua, John M.; Trono, Ruben; Edmonds, Charles H.; Norman, John C.

    1978-01-01

    Our laboratories are engaged in the design of a clinically-oriented electrically actuated long-term intracorporeal (abdominal) left ventricular assist device (“E-type” ALVAD) or partial artificial heart. This infradiaphragmatic blood pump is designed to be powered by implantable electrical to mechanical energy converter systems. The following analyses were undertaken to: [List: see text] The proposed “E-type” ALVAD should be capable of pumping 4-7 liters per minute at heart rates of 75-100 beats per minute during rest, and 10 liters per minute at rates of 120 beats per minute during moderate exercise. These performance levels should be exceeded with a maximum device stroke volume of 85-90 ml and a mean pump inflow (filling) impedance of ≤ 0.072 gm/sec/cm−5. Images PMID:15216070

  6. Heart failure - surgeries and devices

    MedlinePlus

    ... signal to your heart. The signal makes your heart beat at the correct pace. Pacemakers may be used: To correct abnormal heart rhythms. The heart may beat too slowly, too fast, or in an irregular ...

  7. Development of a totally implantable artificial heart.

    PubMed

    Rowles, J R; Khanwilkar, P S; Diegel, P D; Hansen, A C; Bearnson, G B; Smith, K D; Tatsumi, E; Olsen, D B

    1992-01-01

    The first generation of an integrated, totally implantable electrohydraulic total artificial heart was designed for long-term cardiac replacement. The system consists of an elliptical blood pump with an interatrial shunt, Medtronic-Hall 27 mm and 25 mm inflow and outflow valves, respectively, an energy converter consisting of an axial-flow, hydraulic pump driven by a brushless DC motor, and an electronics system with transcutaneous energy transmission and telemetry. Energy is supplied by internal nickel-cadmium rechargeable batteries that supply power for 20 min and external silver-zinc batteries that are designed to supply energy to run the system for 5 hr. The blood pump consists of a single layer diaphragm cast from Biolon, with joined right and left ventricles sharing a common base. The dynamic stroke volume is 84 ml, and maximum cardiac output is 9.2 L/min at a heart rate of 110 beats/min on the mock circulation. A 4.3 mm diameter interatrial shunt is used to balance the volumetrically coupled ventricles. The energy converter pumps hydraulic fluid alternately between ventricles, with controlled, active filling in one ventricle during the systolic phase of the other ventricle. Internal or external controllers adjust the heart rate and motor speed to maintain normal atrial filling pressures and full stroke. Electromagnetic induction is used to transfer energy through the skin and a bidirectional infrared data link incorporated within the transcutaneous energy transmission coils is used to transmit information. The entire system is being assembled and refined for long-term animal implant studies. PMID:1457955

  8. Present and future perspectives on total artificial hearts

    PubMed Central

    Gerosa, Gino; Scuri, Silvia; Iop, Laura

    2014-01-01

    Due to shortages in donor organ availability, advanced heart-failure patients are at high risk of further decompensation and often death while awaiting transplantation. This shortage has led to the development of effective mechanical circulatory support (MCS). Currently, various implantable ventricular-assist devices (VADs) are able to provide temporary or long-term circulatory support for many end-stage heart-failure patients. Implantation of a total artificial heart (TAH) currently represents the surgical treatment option for patients requiring biventricular MCS as a bridge to transplant (BTT) or destination therapy (DT). However, the clinical applicability of available versions of positive displacement pumps is limited by their size and associated complications. Application of advanced technology is aimed at solving some of these issues, attempting to develop a new generation of smaller and more effective TAHs to suit a wider patient population. Particular targets for improvement include modifications to the biocompatibility of device designs and materials in order to decrease hemorrhagic and thromboembolic complications. Meanwhile, new systems to power implanted driving units which are fully operational without interruption of skin barriers represent a potential means of decreasing the risk of infections. In this review, we will discuss the history of the TAH, its development and clinical application, the implications of the existing technological solutions, published outcomes and the future outlook for TAHs. PMID:25512901

  9. Artificial neural network circuits with Josephson devices

    SciTech Connect

    Harada, Y.; Goto, E. )

    1991-03-01

    This article describes a new approach of Josephson devices for computer applications. With an artificial neural network scheme Josephson devices is expected to develop a new paradigm for future computer systems. Here the authors discuss circuit configuration for a neuron with Josephson devices. The authors proposed a combination of a variable bias source and Josephson devices for a synapse circuit. The bias source signal is steered by the Josephson device input signal and becomes the synapse output signal. These output signals are summed up at the specific resistor or inductor to produce the weighted sum of Josephson devices input signals. According to the error signal, the bias source value is corrected. This corresponds to the learning procedure.

  10. An artificial heart driven by liquid gas.

    PubMed

    Abe, Y; Chinzei, T; Imachi, K; Mabuchi, K; Atsumi, K; Fujimasa, I

    1990-01-01

    An artificial heart (AH) driving system, in which a sac or diaphragm type blood pump is liquid gas driven, is designed. The working mechanism of this system is as follows: 1) liquid gas is used for the driving source; 2) a liquid gas is stored in its liquid state in the circuit; 3) a liquid gas is vaporized, and the vaporizing pressure squeezes the blood pump, causing ejection of blood; 4) vaporized gas is aspirated and compressed by a small compressor to liquefaction through the heat exchanger, then negative pressure is applied to the blood pump and blood is aspirated; and 5) the blood pump is driven in this closed cycle. To demonstrate the mechanism of this system, a prototype was developed using Freon 114 as the liquid gas. In this system, the maximum flow of the AH at a 100 pulse per minute rate, was about 6.9 L/min, using a 90 ml sac type blood pump. The advantages of this AH driving mechanism are as follows: 1) a small system is available because pressure chambers are not necessary; 2) a biventricular system is available, with a single compressor; 3) no compliance chamber is necessary if the system is small enough to be implanted.

  11. An artificial heart driven by liquid gas.

    PubMed

    Abe, Y; Chinzei, T; Imachi, K; Mabuchi, K; Atsumi, K; Fujimasa, I

    1990-01-01

    An artificial heart (AH) driving system, in which a sac or diaphragm type blood pump is liquid gas driven, is designed. The working mechanism of this system is as follows: 1) liquid gas is used for the driving source; 2) a liquid gas is stored in its liquid state in the circuit; 3) a liquid gas is vaporized, and the vaporizing pressure squeezes the blood pump, causing ejection of blood; 4) vaporized gas is aspirated and compressed by a small compressor to liquefaction through the heat exchanger, then negative pressure is applied to the blood pump and blood is aspirated; and 5) the blood pump is driven in this closed cycle. To demonstrate the mechanism of this system, a prototype was developed using Freon 114 as the liquid gas. In this system, the maximum flow of the AH at a 100 pulse per minute rate, was about 6.9 L/min, using a 90 ml sac type blood pump. The advantages of this AH driving mechanism are as follows: 1) a small system is available because pressure chambers are not necessary; 2) a biventricular system is available, with a single compressor; 3) no compliance chamber is necessary if the system is small enough to be implanted. PMID:2252673

  12. Ventricular assist device in univentricular heart physiology.

    PubMed

    Brancaccio, Gianluca; Gandolfo, Fabrizio; Carotti, Adriano; Amodeo, Antonio

    2013-04-01

    The use of mechanical cardiac assistance is well established as a bridge to orthotopic heart transplantation (OHT) or to recovery for patients with congestive heart failure, however, the experience in single ventricle (SV) physiology is still limited. We report two cases of mechanical assistance in patients with SV physiology: a 2-year old male with hypoplastic left heart syndrome who underwent Norwood Stage I and II followed by HF and a 4-year old female with a univentricular heart who developed a severe right ventricular dysfunction 2 years after a cavopulmonary shunt. Mechanical support utilizing ventricular assist devices (VADs) is considered a valid tool to bridge patients with congestive heart failure to either OHT or to recovery. Increasing experience and improved outcomes utilizing this technology in children with biventricular hearts have led to considering employing these devices in failing SV treatment. We present 2 cases of terminally ill children with SV who were assisted with a VAD.

  13. [Caecal volvulus after heart surgery with artificial circulation].

    PubMed

    Korostelev, A N; Kuznetsov, A M; Chzhao, A V

    2016-01-01

    Presented herein is a description of a rare complication, i.e. caecal volvulus, after heart surgery. This case report illustrates difficulty of diagnosis of abdominal organs complications after artificial circulation and necessity of active surgical policy. PMID:27336350

  14. Development of a totally implantable total artificial heart controller.

    PubMed

    Lee, S H; Choi, W W; Min, B G

    1991-01-01

    Using a one chip microcontroller, 87C196 (One chip EPROM), and an erasable and programmable logic device (EPLD), an implantable control system to drive a pendulum type electromechanical total artificial heart was developed. This control system consists of four parts: a main management system, a motor driver with power regulator, a state monitoring system, and a communication portion. The main system has a speed detector, proportional and integral (PI) control, pulse width modulation (PWM) generation, serial communication, and an analog data processor. Two kinds of power system are used, separated by eight photocoupler arrays to improve system stability. When the performance of each compartment was compared with that of the previously used Z80 microprocessor based control system, good correspondence was shown. Logic power consumption was reduced to one third that of the previous controller. Using mock circulation tests, the overall performance of the control system was evaluated.

  15. Artificial leaf device for solar fuel production.

    PubMed

    Amao, Yutaka; Shuto, Naho; Furuno, Kana; Obata, Asami; Fuchino, Yoshiko; Uemura, Keiko; Kajino, Tsutomu; Sekito, Takeshi; Iwai, Satoshi; Miyamoto, Yasushi; Matsuda, Masatoshi

    2012-01-01

    Solar fuels, such as hydrogen gas produced from water and methanol produced from carbon dioxide reduction by artificial photosynthesis, have received considerable attention. In natural leaves the photosynthetic proteins are well-organized in the thylakoid membrane. To develop an artificial leaf device for solar low-carbon fuel production from CO2, a chlorophyll derivative chlorin-e6 (Chl-e6; photosensitizer), 1-carboxylundecanoyl-1'-methyl-4,4'-bipyrizinium bromide, iodide (CH3V(CH2)9COOH; the electron carrier) and formate dehydrogenase (FDH) (the catalyst) immobilised onto a silica-gel-based thin layer chromatography plate (the Chl-V-FDH device) was investigated. From luminescence spectroscopy measurements, the photoexcited triplet state of Chl-e6 was quenched by the CH3V(CH2)9COOH moiety on the device, indicating the photoinduced electron transfer from the photoexcited triplet state of Chl-e6 to the CH3V(CH2)9COOH moiety. When the CO2-saturated sample solution containing NADPH (the electron donor) was flowed onto the Chl-V-FDH device under visible light irradiation, the formic acid concentration increased with increasing irradiation time.

  16. Testing of Safety-Critical Software Embedded in an Artificial Heart

    NASA Astrophysics Data System (ADS)

    Cha, Sungdeok; Jeong, Sehun; Yoo, Junbeom; Kim, Young-Gab

    Software is being used more frequently to control medical devices such as artificial heart or robotic surgery system. While much of software safety issues in such systems are similar to other safety-critical systems (e.g., nuclear power plants), domain-specific properties may warrant development of customized techniques to demonstrate fitness of the system on patients. In this paper, we report results of a preliminary analysis done on software controlling a Hybrid Ventricular Assist Device (H-VAD) developed by Korea Artificial Organ Centre (KAOC). It is a state-of-the-art artificial heart which completed animal testing phase. We performed software testing in in-vitro experiments and animal experiments. An abnormal behaviour, never detected during extensive in-vitro analysis and animal testing, was found.

  17. Past and Present of Total Artificial Heart Therapy: A Success Story

    PubMed Central

    Samak, Mostafa; Fatullayev, Javid; Sabashnikov, Anton; Zeriouh, Mohamed; Rahmanian, Parwis B.; Choi, Yeong-Hoon; Wippermann, Jens; Wahlers, Thorsten; Schmack, Bastian; Ruhparwar, Arjang; Dohmen, Pascal M.; Karck, Matthias; Popov, Aron-Frederik; Simon, André R.; Weymann, Alexander

    2015-01-01

    The totally artificial heart (TAH) is among the most prominent medical innovations of the 21st century, especially due to the increasing population with end-stage heart failure. The progressive course of the disease, its resistance to conventional therapy, and the scarcity of hearts available for transplantation were the prime impetus for developing a TAH, especially when other options of mechanical circulatory assist devices are exhausted. In this review, we narrate the history of TAH, give an overview of its technology, and address the pros and cons of the currently available TAH models in light of published clinical experience. PMID:26343363

  18. Domestic and foreign trends in the prevalence of heart failure and the necessity of next-generation artificial hearts: a survey by the Working Group on Establishment of Assessment Guidelines for Next-Generation Artificial Heart Systems.

    PubMed

    Tatsumi, Eisuke; Nakatani, Takeshi; Imachi, Kou; Umezu, Mitsuo; Kyo, Shun-Ei; Sase, Kazuhiro; Takatani, Setsuo; Matsuda, Hikaru

    2007-01-01

    A series of guidelines for development and assessment of next-generation medical devices has been drafted under an interagency collaborative project by the Ministry of Health, Labor and Welfare and the Ministry of Economy, Trade and Industry. The working group for assessment guidelines of next-generation artificial hearts reviewed the trend in the prevalence of heart failure and examined the potential usefulness of such devices in Japan and in other countries as a fundamental part of the process of establishing appropriate guidelines. At present, more than 23 million people suffer from heart failure in developed countries, including Japan. Although Japan currently has the lowest mortality from heart failure among those countries, the number of patients is gradually increasing as our lifestyle becomes more Westernized; the associated medical expenses are rapidly growing. The number of heart transplantations, however, is limited due to the overwhelming shortage of donor hearts, not only in Japan but worldwide. Meanwhile, clinical studies and surveys have revealed that the major causes of death in patients undergoing long-term use of ventricular assist devices (VADs) were infection, thrombosis, and mechanical failure, all of which are typical of VADs. It is therefore of urgent and universal necessity to develop next-generation artificial hearts that have excellent durability to provide at least 2 years of event-free operation with a superior quality of life and that can be used for destination therapy to save patients with irreversible heart failure. It is also very important to ensure that an environment that facilitates the development, testing, and approval evaluation processes of next-generation artificial hearts be established as soon as possible.

  19. Elective Inactivation of Total Artificial Heart Technology in Non-Futile Situations: Inpatients, Outpatients and Research Participants

    ERIC Educational Resources Information Center

    Bramstedt, Katrina A.

    2004-01-01

    Total artificial heart technology as a potential clinical therapy raises the issue of elective device inactivation in both futile and non-futile situations. This article explores elective device inactivation in non-futile situations. In reply to such requests for inactivation, the medical team should reflect on the individual's decision-making…

  20. Artificial balancer - supporting device for postural reflex.

    PubMed

    Wojtara, Tytus; Sasaki, Makoto; Konosu, Hitoshi; Yamashita, Masashi; Shimoda, Shingo; Alnajjar, Fady; Kimura, Hidenori

    2012-02-01

    The evolutionarily novel ability to keep ones body upright while standing or walking, the human balance, deteriorates in old age or can be compromised after accidents or brain surgeries. With the aged society, age related balance problems are on the rise. Persons with balance problems are more likely to fall during their everyday life routines. Especially in elderly, falls can lead to bone fractures making the patient bedridden, weakening the body and making it more prone to other diseases. Health care expenses for a fall patient are often very high. There is a great deal of research being done on exoskeletons and power assists. However, these technologies concentrate mainly on the amplifications of human muscle power while balance has to be provided by the human themself. Our research has been focused on supporting human balance in harmony with the human's own posture control mechanisms such as postural reflexes. This paper proposes an artificial balancer that supports human balance through acceleration of a flywheel attached to the body. Appropriate correcting torques are generated through our device based on the measurements of body deflections. We have carried out experiments with test persons standing on a platform subject to lateral perturbations and ambulatory experiments while walking on a balance beam. These experiments have demonstrated the effectiveness of our device in supporting balance and the possibility of enhancing balance-keeping capability in human beings through the application of external torque. PMID:22169384

  1. Ripple reduction control of the undulation pump total artificial heart.

    PubMed

    Saito, Itsuro; Chinzei, Tsuneo; Mochizuki, Shuichi; Abe, Yusuke; Isoyama, Takashi; Iwasaki, Kiyotaka; Suzuki, Takafumi; Karita, Tatsuro; Ono, Toshiya; Kouno, Akimasa; Ishimaru, Mitsuhiko; Baba, Atsushi; Ozeki, Toshinaga; Tohyama, Takahiro; Kobayashi Si, Shin-ichi; Imachi, Kou

    2002-01-01

    An undulation pump total artificial heart (UPTAH) in which the revolutions of the motor are converted to undulation motion of a disk has been developed. In an experiment, a goat using the UPTAH survived for 54 days. However, a large ripple was observed in the device's output pressure and flow waveform. In calculating the spectrum of the ripple, we found that the ripple mainly comprised 2 frequency sine waves: 1 having the same frequency as and 1 having double the frequency of the motor revolutions. To reduce the ripple, 2 sine waves, 1 having the same frequency as and 1 having double the frequency of the motor revolutions, were provided to the motor current to modulate the pulse width of the pulse width modulation controlling the motor revolutions. This ripple control method reduced the pressure ripple by 90% in a mock circulation and by 70% in animal experiments. These results revealed that the ripple generated in the UPTAH could be controlled through the use of motor control software.

  2. Inspection of an artificial heart by the neutron radiography technique

    NASA Astrophysics Data System (ADS)

    Pugliesi, R.; Geraldo, L. P.; Andrade, M. L. G.; Menezes, M. O.,; Pereira, M. A. S.; Maizato, M. J. S.

    1999-11-01

    The neutron radiography technique was employed to inspect an artificial heart prototype which is being developed to provide blood circulation for patients expecting heart transplant surgery. The radiographs have been obtained by the direct method with a gadolinium converter screen along with the double coated Kodak-AA emulsion film. The artificial heart consists of a flexible plastic membrane located inside a welded metallic cavity, which is employed for blood pumping purposes. The main objective of the present inspection was to identify possible damages in this plastic membrane, produced during the welding process of the metallic cavity. The obtained radiographs were digitized as well as analysed in a PC and the improved images clearly identify several damages in the plastic membrane, suggesting changes in the welding process.

  3. Control strategies for afterload reduction with an artificial vasculature device.

    PubMed

    Giridharan, Guruprasad A; Cheng, Rolando Chip; Glower, Jacob S; Ewert, Daniel L; Sobieski, Michael A; Slaughter, Mark S; Koenig, Steven C

    2012-01-01

    Ventricular assist devices (VADs) have been used successfully as a bridge to transplant in heart failure patients by unloading ventricular volume and restoring the circulation. An artificial vasculature device (AVD) is being developed that may better facilitate myocardial recovery than VAD by controlling the afterload experienced by the native heart and controlling the pulsatile energy entering into the arterial system from the device, potentially reconditioning the arterial system properties. The AVD is a valveless, 80 ml blood chamber with a servo-controlled pusher plate connected to the ascending aorta by a vascular graft. Control algorithms for the AVD were developed to maintain any user-defined systemic input impedance (IM) including resistance, elastance, and inertial components. Computer simulation and mock circulation models of the cardiovascular system were used to test the efficacy of two control strategies for the AVD: 1) average impedance position control (AIPC)-to maintain an average value of resistance during left ventricular (LV) systole and 2) instantaneous impedance force feedback (IIFF) and position control (IIPC)-to maintain a desired value or profile of resistance and compliance. Computer simulations and mock loop tests were performed to predict resulting cardiovascular pressures, volumes, flows, and the resistance and compliance experienced by the native LV during ejection for simulated normal, failing, and recovering LV. These results indicate that the LV volume and pressure decreased, and the LV stroke volume increased with decreasing IM, resulting in an increased ejection fraction. Although the AIPC algorithm is more stable and can tolerate higher levels of sensor errors and noise, the IIFF and IIPC control algorithms are better suited to maintain any instantaneous IM or an IM profile. The developed AVD impedance control algorithms may be implemented with current VADs to promote myocardial recovery and facilitate weaning. PMID:22635010

  4. Control strategies for afterload reduction with an artificial vasculature device.

    PubMed

    Giridharan, Guruprasad A; Cheng, Rolando Chip; Glower, Jacob S; Ewert, Daniel L; Sobieski, Michael A; Slaughter, Mark S; Koenig, Steven C

    2012-01-01

    Ventricular assist devices (VADs) have been used successfully as a bridge to transplant in heart failure patients by unloading ventricular volume and restoring the circulation. An artificial vasculature device (AVD) is being developed that may better facilitate myocardial recovery than VAD by controlling the afterload experienced by the native heart and controlling the pulsatile energy entering into the arterial system from the device, potentially reconditioning the arterial system properties. The AVD is a valveless, 80 ml blood chamber with a servo-controlled pusher plate connected to the ascending aorta by a vascular graft. Control algorithms for the AVD were developed to maintain any user-defined systemic input impedance (IM) including resistance, elastance, and inertial components. Computer simulation and mock circulation models of the cardiovascular system were used to test the efficacy of two control strategies for the AVD: 1) average impedance position control (AIPC)-to maintain an average value of resistance during left ventricular (LV) systole and 2) instantaneous impedance force feedback (IIFF) and position control (IIPC)-to maintain a desired value or profile of resistance and compliance. Computer simulations and mock loop tests were performed to predict resulting cardiovascular pressures, volumes, flows, and the resistance and compliance experienced by the native LV during ejection for simulated normal, failing, and recovering LV. These results indicate that the LV volume and pressure decreased, and the LV stroke volume increased with decreasing IM, resulting in an increased ejection fraction. Although the AIPC algorithm is more stable and can tolerate higher levels of sensor errors and noise, the IIFF and IIPC control algorithms are better suited to maintain any instantaneous IM or an IM profile. The developed AVD impedance control algorithms may be implemented with current VADs to promote myocardial recovery and facilitate weaning.

  5. Experiences with a sac-type artificial heart

    PubMed Central

    Morris, David T.; Couves, Cecil M.

    1971-01-01

    A total replacement artificial heart is described having in vitro performance satisfying human requirements up to and including moderate work. The in vitro design has been modified to make its implantation into the chests of experimental animals technically feasible. The heart has been tested in vivo for up to six hours, and has been found to provide the experimental animals with adequate blood flow and pressures. Preliminary tests have shown major problems of air embolism and red blood cell hemolysis. The heart design and technique of implantation are undergoing further improvement. Performance will be more comprehensively examined with the use of larger experimental animals in order more accurately to evaluate the heart's potential. ImagesFIG. 1FIG. 2FIG. 3FIG. 4FIG. 5FIG. 6FIG. 7FIG. 8FIG. 9FIG. 10 PMID:5112120

  6. The Thoratec system implanted as a modified total artificial heart: the Bad Oeynhausen technique.

    PubMed

    Arusoglu, Latif; Reiss, Nils; Morshuis, Michiel; Schoenbrodt, Michael; Hakim-Meibodi, Kavous; Gummert, Jan

    2010-12-01

    The CardioWest™ total artificial heart (SynCardia Systems, Tuscon, AZ, USA) is the only FDA-approved total artificial heart determined as a bridge to human heart transplantation for patients dying of biventricular heart failure. Implantation provides immediate hemodynamic restoration and clinical stabilization, leading to end-organ recovery and thus eventually allowing cardiac transplantation. Occasionally, implantation of a total artificial heart is not feasible for anatomical reasons. For this patient group, we have developed an alternative technique using the paracorporeal Thoratec biventricular support system (Thoratec, Pleasanton, CA, USA) as a modified total artificial heart. A detailed description of the implantation technique is presented.

  7. Numerical Simulation of Flow Through an Artificial Heart

    NASA Technical Reports Server (NTRS)

    Rogers, Stuart E.; Kutler, Paul; Kwak, Dochan; Kiris, Cetin

    1989-01-01

    A solution procedure was developed that solves the unsteady, incompressible Navier-Stokes equations, and was used to numerically simulate viscous incompressible flow through a model of the Pennsylvania State artificial heart. The solution algorithm is based on the artificial compressibility method, and uses flux-difference splitting to upwind the convective terms; a line-relaxation scheme is used to solve the equations. The time-accuracy of the method is obtained by iteratively solving the equations at each physical time step. The artificial heart geometry involves a piston-type action with a moving solid wall. A single H-grid is fit inside the heart chamber. The grid is continuously compressed and expanded with a constant number of grid points to accommodate the moving piston. The computational domain ends at the valve openings where nonreflective boundary conditions based on the method of characteristics are applied. Although a number of simplifing assumptions were made regarding the geometry, the computational results agreed reasonably well with an experimental picture. The computer time requirements for this flow simulation, however, are quite extensive. Computational study of this type of geometry would benefit greatly from improvements in computer hardware speed and algorithm efficiency enhancements.

  8. Computational flow visualization in vibrating flow pump type artificial heart by unstructured grid.

    PubMed

    Kato, Takuma; Kawano, Satoyuki; Nakahashi, Kazuhiro; Yambe, Tomoyuki; Nitta, Shin-ichi; Hashimoto, Hiroyuki

    2003-01-01

    Computational flow visualization in the casing of vibrating flow pump (VFP) was made for various conditions based on the novel techniques of fluid dynamics. VFP type artificial heart can generate the oscillated flow and can be applied to the left ventricular assist device. Flow pattern of blood in an artificial heart is closely connected to mechanical performance and serious biomechanical problems such as hemolysis and blood coagulation. To effectively design the VFP for a left ventricular assist device, the numerical codes for solving Navier-Stokes equations were developed for three-dimensional blood flow based on the finite volume method. Furthermore, the simulation techniques based on the artificial compressibility method and the unstructured grid were also developed here. The numerical calculations were based on the precise configurations and the flow conditions of the prototype device. From the viewpoint of computational fluid dynamics (CFD), the detailed discussion of flow patterns in the casing of VFP, which were closely connected with hemolysis and blood coagulation, was made and the computational results were visualized by the use of the recent technique of computational graphics. Some useful design data of VFP were presented. PMID:12534712

  9. Animal Experiments of the Helical Flow Total Artificial Heart.

    PubMed

    Abe, Yusuke; Isoyama, Takashi; Saito, Itsuro; Inoue, Yusuke; Ishii, Kohei; Sato, Masami; Hara, Shintaro; Yurimoto, Terumi; Li, Xinyang; Murakami, Haruka; Ariyoshi, Koki; Kawase, Yukino; Ono, Toshiya; Fukazawa, Kyoko; Ishihara, Kazuhiko

    2015-08-01

    Severe cardiac failure patients require a total artificial heart (TAH) to save life. To realize a TAH that can fit a body of small stature and has high performance, high durability, good anatomical fitting, good blood compatibility, and physiological control, we have been developing the helical flow TAH (HFTAH) with two helical flow pumps with hydrodynamic levitation impeller. Animal experiments of the HFTAH were conducted to perform in vivo studies. The HFTAH was implanted in 13 adult female goats weighing 45.0-64.0 kg. After surgery, neither anti-coagulant nor anti-platelet medication was given systemically. The HFTAH was usually driven with a quasi-pulsatile mode. The 1/R control or ΔP control was applied to control the circulation. The ΔP control is a new method using simplified equation of the 1/R control. The HFTAH could be implanted in all goats with good anatomical fitting. Two goats survived for a long time (100 and 68 days). Major causes of termination were device failure and surgical complications. In the device failure, trouble with hydrodynamic bearing was conspicuous. In the two long-term survived goats, experiments were terminated with bearing instability that was probably caused by the suction effect. In these goats, hemolysis occurred on postoperative day 88 and 44, which was considered to be relevant to the bearing trouble. Thrombus was found at the broken right bearing of the 100-day survived goat. However, antithrombogenicity of the pump is expected to be good unless bearing trouble occurs. In two long-term survived goats, the 1/R control or ΔP control worked appropriately to prevent the elevation of right atrial pressure. In both goats, hemodynamic parameters changed with the condition of the animals, liver and kidney functions remained almost normal except when recovering from surgery and during hemolysis, and total protein recovered 2 weeks after surgery. Although instability of the hydrodynamic bearing should be improved, performance of

  10. Heart Surgery Devices May Have Been Contaminated: CDC

    MedlinePlus

    ... 161469.html Heart Surgery Devices May Have Been Contaminated: CDC Patients who experience night sweats, fever, weight ... used during open heart surgery may have been contaminated with bacteria that puts patients at risk for ...

  11. Present and future of the artificial heart driving system.

    PubMed

    Shumakov, V I; Itkin, G P; Sumin, A V; Mordashov, V M; Kiselev, U M; Zimin, N K; Drobyshev, A A

    1991-10-01

    The totally artificial heart (TAH) is now in development in two trends. First, there is the development of a bridge system for temporary support of cardiac function. The TAH with the extracorporeal pneumatic driving system Sinus-IS is more efficient and safer. Parallel with this, a portable pneumatic driving system has been developed. That can be considered a stage in the development of the second trend: a totally implantable TAH. This article reviews problems of building of the Micron energy system to be used in implantable TAH designs.

  12. Artificial heart for humanoid robot using coiled SMA actuators

    NASA Astrophysics Data System (ADS)

    Potnuru, Akshay; Tadesse, Yonas

    2015-03-01

    Previously, we have presented the design and characterization of artificial heart using cylindrical shape memory alloy (SMA) actuators for humanoids [1]. The robotic heart was primarily designed to pump a blood-like fluid to parts of the robot such as the face to simulate blushing or anger by the use of elastomeric substrates for the transport of fluids. It can also be used for other applications. In this paper, we present an improved design by using high strain coiled SMAs and a novel pumping mechanism that uses sequential actuation to create peristalsis-like motions, and hence pump the fluid. Various placements of actuators will be investigated with respect to the silicone elastomeric body. This new approach provides a better performance in terms of the fluid volume pumped.

  13. [Artificial drainage devices--history, indications].

    PubMed

    Barac, Ileana Ramona; Pop, Monica

    2012-01-01

    Glaucoma is a degenerative optic neuropathy progressive, multifactorial, which can lead to blindness. Blindness in patients with glaucoma is defined as visual field reduction below 10 degrees. Artificial drainage systems are a solution for refractory to medication, laser treatment or conventional surgery. Used by over 100 years, improved with good surgical technique and careful patient follow-up surgery, postoperative results are satisfactory. PMID:22888679

  14. Results with SynCardia total artificial heart beyond 1 year.

    PubMed

    Torregrossa, Gianluca; Morshuis, Michiel; Varghese, Robin; Hosseinian, Leila; Vida, Vladimiro; Tarzia, Vincenzo; Loforte, Antonio; Duveau, Daniel; Arabia, Francisco; Leprince, Pascal; Kasirajan, Vigneshwa; Beyersdorf, Friedhelm; Musumeci, Francesco; Hetzer, Roland; Krabatsch, Thoamas; Gummert, Jan; Copeland, Jack; Gerosa, Gino

    2014-01-01

    Mechanical circulatory support devices have been increasingly used for long-term support. We reviewed outcomes in all patients supported with a SynCardia total artificial heart (TAH) for more than 1 year to assess its safety in long-term support. As of December 2011, all 47 patients who received the TAH from 10 centers worldwide were included in this retrospective study. Clinical data were collected on survival, infections, thromboembolic and hemorrhagic events, device failures, and antithrombotic therapy. The mean age of patients was 50 ± 1.57 years, the median support time was 554 days (range 365-1373 days). The primary diagnosis was dilated cardiomiopathy in 23 patients, ischemic in 15, and "other" in 9. After a minimum of 1 year of support, 34 patients (72%) were successfully transplanted, 12 patients (24%) died while on device support, and 1 patient (2%) is still supported. Five patients (10%) had a device failure reported. Major complications were as follows: systemic infections in 25 patients (53%), driveline infections in 13 patients (27%), thromboembolic events in 9 patients (19%), and hemorrhagic events in 7 patients (14%). SynCardia TAH has proven to be a reliable and effective device in replacing the entire heart. In patients who reached a minimum of 1 year of support, device failure rate is acceptable and only in two cases was the leading cause of death. Infections and hemorrhagic events were the major causes of death. Patients who remain supported beyond 1 year are still likely to survive to transplantation.

  15. A hybrid mock circulation loop for a total artificial heart.

    PubMed

    Nestler, Frank; Bradley, Andrew P; Wilson, Stephen J; Timms, Daniel L; Frazier, O Howard; Cohn, William E

    2014-09-01

    Rotary blood pumps are emerging as a viable technology for total artificial hearts, and the development of physiological control algorithms is accelerated with new evaluation environments. In this article, we present a novel hybrid mock circulation loop (HMCL) designed specifically for evaluation of rotary total artificial hearts (rTAH). The rTAH is operated in the physical domain while all vasculature elements are embedded in the numerical domain, thus combining the strengths of both approaches: fast and easy exchange of the vasculature model together with improved controllability of the pump. Parameters, such as vascular resistance, compliance, and blood volume, can be varied dynamically in silico during operation. A hydraulic-numeric interface creates a real-time feedback loop between the physical and numerical domains. The HMCL uses computer-controlled resistance valves as actuators, thereby reducing the size and number of hydraulic elements. Experimental results demonstrate a stable interaction over a wide operational range and a high degree of flexibility. Therefore, we demonstrate that the newly created design environment can play an integral part in the hydraulic design, control development, and durability testing of rTAHs. PMID:25234760

  16. Effective ultraviolet irradiance measurements from artificial tanning devices in Greece.

    PubMed

    Petri, Aspasia; Karabetsos, Efthymios

    2015-12-01

    Artificial tanning remains very popular worldwide, despite the International Agency for Research on Cancer classification of ultraviolet (UV) radiation from sunbeds as 'carcinogenic to humans'. Greek Atomic Energy Commission has initiated a surveillance action of the artificial tanning devices in Greece in order to record the effective irradiance levels from the sunbeds and to inform and synchronise the domestic artificial tanning business sector with the requirements of the European Standard EN 60335-2-27:2010. In this direction, in situ measurements of UV emissions from sunbeds in solaria businesses all over Greece were performed from October 2013 until July 2014, with a radiometer and a portable single-monochromator spectrophotometer. Analysis of the measurements' results revealed that effective irradiance in ∼60 % of the measured sunbeds exceeded the 0.3 W m(-2) limit value set by EN 60335-2-27:2010 and only 20 % of the devices could be categorised as UV type 3.

  17. Role of total artificial heart in the management of heart transplant rejection and retransplantation: case report and review.

    PubMed

    Kalya, Anantharam; Jaroszewski, Dawn; Pajaro, Octavio; Scott, Robert; Gopalan, Radha; Kasper, Diane; Arabia, Francisco

    2013-01-01

    Cardiac allograft rejection and failure may require mechanical circulatory support as bridge-to-retransplantation. Prognosis in this patient group is poor and implantable ventricular assist devices have had limited success due to organ failure associated with the high dose immunosuppression required to treat ongoing rejection. We present a case from our institution and the world-wide experience utilizing the SynCardia CardioWest Total Artificial Heart (TAH-t; SynCardia Systems, Inc., Tucson, AZ, USA) for replacement of the failing graft, recovery of patient and end-organ failure with ultimate bridge to retransplantation. We present our experience and review of world-wide experience for use of TAH-t in this type patient.

  18. Devices and circuits for nanoelectronic implementation of artificial neural networks

    NASA Astrophysics Data System (ADS)

    Turel, Ozgur

    Biological neural networks perform complicated information processing tasks at speeds better than conventional computers based on conventional algorithms. This has inspired researchers to look into the way these networks function, and propose artificial networks that mimic their behavior. Unfortunately, most artificial neural networks, either software or hardware, do not provide either the speed or the complexity of a human brain. Nanoelectronics, with high density and low power dissipation that it provides, may be used in developing more efficient artificial neural networks. This work consists of two major contributions in this direction. First is the proposal of the CMOL concept, hybrid CMOS-molecular hardware [1-8]. CMOL may circumvent most of the problems in posed by molecular devices, such as low yield, vet provide high active device density, ˜1012/cm 2. The second contribution is CrossNets, artificial neural networks that are based on CMOL. We showed that CrossNets, with their fault tolerance, exceptional speed (˜ 4 to 6 orders of magnitude faster than biological neural networks) can perform any task any artificial neural network can perform. Moreover, there is a hope that if their integration scale is increased to that of human cerebral cortex (˜ 1010 neurons and ˜ 1014 synapses), they may be capable of performing more advanced tasks.

  19. First North American 50 cc Total Artificial Heart Experience: Conversion from a 70 cc Total Artificial Heart.

    PubMed

    Khalpey, Zain; Kazui, Toshinobu; Ferng, Alice S; Connell, Alana; Tran, Phat L; Meyer, Mark; Rawashdeh, Badi; Smith, Richard G; Sweitzer, Nancy K; Friedman, Mark; Lick, Scott; Slepian, Marvin J; Copeland, Jack G

    2016-01-01

    The 70 cc total artificial heart (TAH) has been utilized as bridge to transplant (BTT) for biventricular failure. However, the utilization of 70 cc TAH has been limited to large patients for the low output from the pulmonary as well as systemic vein compression after chest closure. Therefore, the 50 cc TAH was developed by SynCardia (Tucson, AZ) to accommodate smaller chest cavity. We report the first TAH exchange from a 70 to 50 cc due to a fit difficulty. The patient failed to be closed with a 70 cc TAH, although the patient met the conventional 70 cc TAH fit criteria. We successfully closed the chest with a 50 cc TAH.

  20. Mechanical Circulatory Support for the Failing Heart: Continuous-Flow Left Ventricular Assist Devices

    PubMed Central

    Englert, Joseph A. R.; Davis, Jennifer A.; Krim, Selim R.

    2016-01-01

    Background: Heart transplantation remains the definitive therapy for patients with advanced heart failure; however, owing to limited donor organ availability and long wait times, continuous-flow left ventricular assist devices (LVADs) have become standard therapy. Methods: This review summarizes the history, progression, function, and basic management of LVADs. Additionally, we provide some clinical pearls and important caveats for managing this unique patient population. Results: Currently, the most common LVADs being implanted in the United States are second- and third-generation devices, the HeartMate II (Thoratec Corp., St. Jude Medical) and the HeartWare HVAD (HeartWare International, Inc.). A newer third-generation pump, the HeartMate III (Thoratec Corp., St. Jude Medical), is designed to create an artificial pulse and is currently under investigation in the United States. Conclusion: LVAD use is promising, will continue to grow, and has become standard therapy for advanced heart failure as a bridge to recovery, as destination therapy, and as a bridge to transplantation. PMID:27660575

  1. Mechanical Circulatory Support for the Failing Heart: Continuous-Flow Left Ventricular Assist Devices

    PubMed Central

    Englert, Joseph A. R.; Davis, Jennifer A.; Krim, Selim R.

    2016-01-01

    Background: Heart transplantation remains the definitive therapy for patients with advanced heart failure; however, owing to limited donor organ availability and long wait times, continuous-flow left ventricular assist devices (LVADs) have become standard therapy. Methods: This review summarizes the history, progression, function, and basic management of LVADs. Additionally, we provide some clinical pearls and important caveats for managing this unique patient population. Results: Currently, the most common LVADs being implanted in the United States are second- and third-generation devices, the HeartMate II (Thoratec Corp., St. Jude Medical) and the HeartWare HVAD (HeartWare International, Inc.). A newer third-generation pump, the HeartMate III (Thoratec Corp., St. Jude Medical), is designed to create an artificial pulse and is currently under investigation in the United States. Conclusion: LVAD use is promising, will continue to grow, and has become standard therapy for advanced heart failure as a bridge to recovery, as destination therapy, and as a bridge to transplantation.

  2. Rapid Speed Modulation of a Rotary Total Artificial Heart Impeller.

    PubMed

    Kleinheyer, Matthias; Timms, Daniel L; Tansley, Geoffrey D; Nestler, Frank; Greatrex, Nicholas A; Frazier, O Howard; Cohn, William E

    2016-09-01

    Unlike the earlier reciprocating volume displacement-type pumps, rotary blood pumps (RBPs) typically operate at a constant rotational speed and produce continuous outflow. When RBP technology is used in constructing a total artificial heart (TAH), the pressure waveform that the TAH produces is flat, without the rise and fall associated with a normal arterial pulse. Several studies have suggested that pulseless circulation may impair microcirculatory perfusion and the autoregulatory response and may contribute to adverse events such as gastrointestinal bleeding, arteriovenous malformations, and pump thrombosis. It may therefore be beneficial to attempt to reproduce pulsatile output, similar to that generated by the native heart, by rapidly modulating the speed of an RBP impeller. The choice of an appropriate speed profile and control strategy to generate physiologic waveforms while minimizing power consumption and blood trauma becomes a challenge. In this study, pump operation modes with six different speed profiles using the BiVACOR TAH were evaluated in vitro. These modes were compared with respect to: hemodynamic pulsatility, which was quantified as surplus hemodynamic energy (SHE); maximum rate of change of pressure (dP/dt); pulse power index; and motor power consumption as a function of pulse pressure. The results showed that the evaluated variables underwent different trends in response to changes in the speed profile shape. The findings indicated a possible trade-off between SHE levels and flow rate pulsatility related to the relative systolic duration in the speed profile. Furthermore, none of the evaluated measures was sufficient to fully characterize hemodynamic pulsatility. PMID:27645393

  3. Supramolecular photochemistry applied to artificial photosynthesis and molecular logic devices.

    PubMed

    Gust, Devens

    2015-01-01

    Supramolecular photochemical systems consist of photochemically active components such as chromophores, electron donors or electron acceptors that are associated via non-covalent or covalent interactions and that interact in some functional way. Examples of interactions are singlet-singlet energy transfer, triplet-triplet energy transfer, photoinduced electron transfer, quantum coherence and spin-spin magnetic interactions. Supramolecular photochemical "devices" may have applications in areas such as solar energy conversion, molecular logic, computation and data storage, biomedicine, sensing, imaging, and displays. This short review illustrates supramolecular photochemistry with examples drawn from artificial photosynthesis, molecular logic, analog photochemical devices and models for avian magnetic orientation. PMID:26515930

  4. Total Artificial Heart as Bridge to Heart Transplantation in Chagas Cardiomyopathy: Case Report.

    PubMed

    Ruzza, A; Czer, L S C; De Robertis, M; Luthringer, D; Moriguchi, J; Kobashigawa, J; Trento, A; Arabia, F

    2016-01-01

    Chagas disease (CD) is becoming an increasingly recognized cause of dilated cardiomyopathy outside of Latin America, where it is endemic, due to population shifts and migration. Heart transplantation (HTx) is a therapeutic option for end-stage cardiomyopathy due to CD, but may be considered a relative contraindication due to potential reactivation of the causative organism with immunosuppression therapy. The total artificial heart (TAH) can provide mechanical circulatory support in decompensated patients with severe biventricular dysfunction until the time of HTx, while avoiding immunosuppressive therapy and removing the organ most affected by the causative organism. We report herein a patient with CD and severe biventricular dysfunction, who had mechanical circulatory support with a TAH for more than 6 months, followed by successful orthotopic HTx and treatment with benznidazole for 3 months. The patient had no evidence of recurrent disease in the transplanted heart based on endomyocardial biopsy up to 1 year post-transplantation, and remains alive more than 30 months after insertion of a TAH and 24 months after HTx. PMID:26915885

  5. Spherical rotary piston machine as an artificial heart.

    PubMed

    Wipf, S L

    1991-01-01

    A positive displacement pump with six rotary pistons was proposed as an artificial heart. The pump's design was characterized by high symmetry and compactness. Thus, a spherical volume of 4 1/4 inch diameter sufficed for a pump delivering 10 L/min at 120 pulses/min with the pistons turning at 30 rpm. The pistons and four connecting gears were the only moving parts. The pump functions in two separate halves as left and right ventricles, with two of the six pistons each having inlet and outlet passages, and one of them replacing mitral and pulmonary valves with the other, tricuspid and aortic valves. The function of the intraventricular septum was provided by the other four pistons whose interiors also accommodated driving motors each capable of 0.4 Nm torque for a combined power of 5 watts. There were no stagnant regions in the pumping volume, and at all internal surfaces in contact with blood, there was periodic shear stress not exceeding approximately 300 Pa.

  6. Spherical rotary piston machine as an artificial heart.

    PubMed

    Wipf, S L

    1991-01-01

    A positive displacement pump with six rotary pistons was proposed as an artificial heart. The pump's design was characterized by high symmetry and compactness. Thus, a spherical volume of 4 1/4 inch diameter sufficed for a pump delivering 10 L/min at 120 pulses/min with the pistons turning at 30 rpm. The pistons and four connecting gears were the only moving parts. The pump functions in two separate halves as left and right ventricles, with two of the six pistons each having inlet and outlet passages, and one of them replacing mitral and pulmonary valves with the other, tricuspid and aortic valves. The function of the intraventricular septum was provided by the other four pistons whose interiors also accommodated driving motors each capable of 0.4 Nm torque for a combined power of 5 watts. There were no stagnant regions in the pumping volume, and at all internal surfaces in contact with blood, there was periodic shear stress not exceeding approximately 300 Pa. PMID:1751131

  7. About the Operation: Heart Transplant

    MedlinePlus

    ... Short gut syndrome Living with Devices Artificial hearts LVADS ICDs Pacemakers Hemodialysis Peritoneal dialysis About Organ Allocation ... because the new heart can act as an assist device if complications occur. Your physician can explain ...

  8. Incompressible viscous flow computations for the pump components and the artificial heart

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin

    1992-01-01

    A finite-difference, three-dimensional incompressible Navier-Stokes formulation to calculate the flow through turbopump components is utilized. The solution method is based on the pseudocompressibility approach and uses an implicit-upwind differencing scheme together with the Gauss-Seidel line relaxation method. Both steady and unsteady flow calculations can be performed using the current algorithm. In this work, the equations are solved in steadily rotating reference frames by using the steady-state formulation in order to simulate the flow through a turbopump inducer. Eddy viscosity is computed by using an algebraic mixing-length turbulence model. Numerical results are compared with experimental measurements and a good agreement is found between the two. Included in the appendix is a paper on incompressible viscous flow through artificial heart devices with moving boundaries. Time-accurate calculations, such as impeller and diffusor interaction, will be reported in future work.

  9. Development of failure detection system based on vibration signal for smart artificial heart: in vitro study.

    PubMed

    Tsujimura, Shinichi; Kuwabara, Takashi; Koguchi, Harutoshi; Yamane, Takashi; Tsutsui, Tatsuo; Sankai, Yoshiyuki

    2008-01-01

    To realize safe and effective medical treatment for patients with implantable artificial hearts, we have developed a smart artificial heart (SAH). The SAH can grasp the mechanical condition of the artificial heart and the physiological condition of the patient. The purpose of this study is to develop a failure detection system based on the vibration signal from artificial heart in order to enhance the ability of failure detection for the SAH. We suppose this vibration signal reflects not only the mechanical condition of the artificial heart but also a part of the physiological condition of the patient. The developed failure detection system is composed of a vibration sensor unit and a failure detection algorithm. The algorithm has a standard frequency pattern, which is made from the vibration signal of good condition of both the artificial heart and patient. Observing the difference from the standard frequency pattern, the algorithm detects failure conditions. Therefore, this algorithm does not need prior knowledge of vibration characteristics corresponding to failures. After confirming that the vibration signal are affected by pump speed and pulsation in two kinds of mock circulatory loops, we performed thrombogenesis detection by using the failure detection system in mock circulatory loop with sheep blood. As a result, this system indicated a possibility of detecting the initial sign of thrombogenesis earlier than current signal. In conclusion, we think that this failure detection system can cooperate with other sensor systems of the SAH and enhance the ability of failure detection for the SAH.

  10. Electrostatic artificial eyelid actuator as an analog micromirror device

    NASA Astrophysics Data System (ADS)

    Goodwin, Scott H.; Dausch, David E.; Solomon, Steven L.; Lamvik, Michael K.

    2005-05-01

    An electrostatic MEMS actuator is described for use as an analog micromirror device (AMD) for high performance, broadband, hardware-in-the-loop (HWIL) scene generation. Current state-of-the-art technology is based on resistively heated pixel arrays. As these arrays drive to the higher scene temperatures required by missile defense scenarios, the power required to drive the large format resistive arrays will ultimately become prohibitive. Existing digital micromirrors (DMD) are, in principle, capable of generating the required scene irradiances, but suffer from limited dynamic range, resolution and flicker effects. An AMD would be free of these limitations, and so represents a viable alternative for high performance UV/VIS/IR scene generation. An electrostatic flexible film actuator technology, developed for use as "artificial eyelid" shutters for focal plane sensors to protect against damaging radiation, is suitable as an AMD for analog control of projection irradiance. In shutter applications, the artificial eyelid actuator contained radius of curvature as low as 25um and operated at high voltage (>200V). Recent testing suggests that these devices are capable of analog operation as reflective microcantilever mirrors appropriate for scene projector systems. In this case, the device would possess larger radius and operate at lower voltages (20-50V). Additionally, frame rates have been measured at greater than 5kHz for continuous operation. The paper will describe the artificial eyelid technology, preliminary measurements of analog test pixels, and design aspects related to application for scene projection systems. We believe this technology will enable AMD projectors with at least 5122 spatial resolution, non-temporally-modulated output, and pixel response times of <1.25ms.

  11. Sleep and wake phase of heart beat dynamics by artificial insymmetrised patterns

    NASA Astrophysics Data System (ADS)

    Dudkowska, A.; Makowiec, D.

    2004-05-01

    In order to determine differences between healthy patients and patients with congestive heart failure we apply the artificial insymmetrised pattern (AIP) method. The AIP method by exploring a human eye ability to extract regularities and read symmetries in a dot pattern, serves a tool for qualitative discrimination of heart rate states.

  12. Soft shape-adaptive gripping device made from artificial muscle

    NASA Astrophysics Data System (ADS)

    Hamburg, E.; Vunder, V.; Johanson, U.; Kaasik, F.; Aabloo, A.

    2016-04-01

    We report on a multifunctional four-finger gripper for soft robotics, suitable for performing delicate manipulation tasks. The gripping device is comprised of separately driven gripping and lifting mechanisms, both made from a separate single piece of smart material - ionic capacitive laminate (ICL) also known as artificial muscle. Compared to other similar devices the relatively high force output of the ICL material allows one to construct a device able to grab and lift objects exceeding multiple times its own weight. Due to flexible design of ICL grips, the device is able to adapt the complex shapes of different objects and allows grasping single or multiple objects simultaneously without damage. The performance of the gripper is evaluated in two different configurations: a) the ultimate grasping strength of the gripping hand; and b) the maximum lifting force of the lifting actuator. The ICL is composed of three main layers: a porous membrane consisting of non-ionic polymer poly(vinylidene fluoride-co-hexafluoropropene) (PVdF-HFP), ionic liquid 1-ethyl-3-methylimidazolium trifluoromethane-sulfonate (EMITFS), and a reinforcing layer of woven fiberglass cloth. Both sides of the membrane are coated with a carbonaceous electrode. The electrodes are additionally covered with thin gold layers, serving as current collectors. Device made of this material operates silently, requires low driving voltage (<3 V), and is suitable for performing tasks in open air environment.

  13. Hemodynamics of a functional centrifugal-flow total artificial heart with functional atrial contraction in goats.

    PubMed

    Shiga, Takuya; Shiraishi, Yasuyuki; Sano, Kyosuke; Taira, Yasunori; Tsuboko, Yusuke; Yamada, Akihiro; Miura, Hidekazu; Katahira, Shintaro; Akiyama, Masatoshi; Saiki, Yoshikatsu; Yambe, Tomoyuki

    2016-03-01

    Implantation of a total artificial heart (TAH) is one of the therapeutic options for the treatment of patients with end-stage biventricular heart failure. There is no report on the hemodynamics of the functional centrifugal-flow TAH with functional atrial contraction (fCFTAH). We evaluated the effects of pulsatile flow by atrial contraction in acute animal models. The goats received fCFTAH that we created from two centrifugal-flow ventricular assist devices. Some hemodynamic parameters maintained acceptable levels: heart rate 115.5 ± 26.3 bpm, aortic pressure 83.5 ± 10.1 mmHg, left atrial pressure 18.0 ± 5.9 mmHg, pulmonary pressure 28.5 ± 9.7 mmHg, right atrial pressure 13.6 ± 5.2 mmHg, pump flow 4.0 ± 1.1 L/min (left) 3.9 ± 1.1 L/min (right), and cardiac index 2.13 ± 0.14 L/min/m(2). fCFTAH with atrial contraction was able to maintain the TAH circulation by forming a pulsatile flow in acute animal experiments. Taking the left and right flow rate balance using the low internal pressure loss of the VAD pumps may be easier than by other pumps having considerable internal pressure loss. We showed that the remnant atrial contraction effected the flow rate change of the centrifugal pump, and the atrial contraction waves reflected the heart rate. These results indicate that remnant atria had the possibility to preserve autonomic function in fCFTAH. We may control fCFTAH by reflecting the autonomic function, which is estimated with the flow rate change of the centrifugal pump.

  14. Artificial Muscle Devices: Innovations and Prospects for Fecal Incontinence Treatment.

    PubMed

    Fattorini, Elisa; Brusa, Tobia; Gingert, Christian; Hieber, Simone E; Leung, Vanessa; Osmani, Bekim; Dominietto, Marco D; Büchler, Philippe; Hetzer, Franc; Müller, Bert

    2016-05-01

    Fecal incontinence describes the involuntary loss of bowel content, which is responsible for stigmatization and social exclusion. It affects about 45% of retirement home residents and overall more than 12% of the adult population. Severe fecal incontinence can be treated by the implantation of an artificial sphincter. Currently available implants, however, are not part of everyday surgery due to long-term re-operation rates of 95% and definitive explantation rates of 40%. Such figures suggest that the implants fail to reproduce the capabilities of the natural sphincter. This article reviews the artificial sphincters on the market and under development, presents their physical principles of operation and critically analyzes their performance. We highlight the geometrical and mechanical parameters crucial for the design of an artificial fecal sphincter and propose more advanced mechanisms of action for a biomimetic device with sensory feedback. Dielectric electro-active polymer actuators are especially attractive because of their versatility, response time, reaction forces, and energy consumption. The availability of such technology will enable fast pressure adaption comparable to the natural feedback mechanism, so that tissue atrophy and erosion can be avoided while maintaining continence during daily activities. PMID:26926695

  15. Etiopathogenesis of hemolytic reactions in total artificial heart recipients.

    PubMed

    Vasků, J; Urbánek, P

    1997-12-01

    Hemolysis in total artificial heart (TAH) recipients was analyzed. From a total of 66 long-term experiments lasting from 30-314 days performed in the Brno Research Center, in 53 animals, the total red blood cell (RBC) count, hematocrit, total hemoglobin, and free plasma hemoglobin were investigated. We could essentially divide the whole group of calves in 2 subgroups. The first subgroup was calves with hemolytic reactions, and the second subgroup was calves without any hemolytic reaction at all. In the first subgroup, hemolysis occurred in 47% of the overall number of animals during extracorporeal circulation (ECC), in 15% during ECC and later periodically during the experiment, in 8% during ECC and then continuously during the experiment, and finally in 10% not during ECC but repeatedly during the experiment. In 20% of the animals from the overall number, hemolysis did not occur at all (second subgroup). These results testify to the great individual differences within 1 breed (Bohemian with a substantial component of Holstein). These differences are further modified by exogenous and endogenous factors. First, the inborn resistance of the RBC membrane and also thrombi formation and the mineralization of the driving diaphragm are very important. The extreme situation of decreased RBC membrane resistance was proved using a calf from another breed, the slow growing Scottish Highland breed, which did not survive 22 days of pumping due to intractable lethal hemolysis. These factors are also indicated by the hemolytic action of some drugs (e.g., Dopegyt) used during the experiment for another reason. Also important are the mechanical forces of pumping, surface moieties of the biomaterial, mineralization of the driving diaphragms, thrombi formation, infection, etc. Essentially, the hemolytic reaction in the TAH recipient has a multifactorial character. Hemolysis is undoubtedly an important factor, which can have a profound impact on the length of survival. The

  16. Design and Evolution of the Asporto Heart Preservation Device

    PubMed Central

    Rivard, Andrew L.

    2015-01-01

    Abstract: The Asporto Heart Preservation Device is a system providing perfusion of cardioplegia to the donor heart using a computer-controlled peristaltic pump in a thermoelectrically cooled and insulated container. In 1998, a user interface was developed at the University of Minnesota consisting of a touch screen and battery-backed microcontroller. Power was supplied by a 120 VAC to 12 VDC converter. An upgrade to the insulated cooler and microcontroller occurred in 2002, which was followed by proof of concept experimental pre-clinical transplants and tests demonstrating the efficacy of the device with isolated donor hearts. During the period between 2002 and 2006, a variety of donor organ containers were developed, modified, and tested to provide an optimal sterile environment and fluid path. Parallel development paths encompass formalized design specifications for final prototypes of the touch screen/microcontroller, organ container, and thermoelectric cooler. PMID:26405361

  17. Design and Evolution of the Asporto Heart Preservation Device.

    PubMed

    Rivard, Andrew L

    2015-06-01

    The Asporto Heart Preservation Device is a system providing perfusion of cardioplegia to the donor heart using a computer-controlled peristaltic pump in a thermoelectrically cooled and insulated container. In 1998, a user interface was developed at the University of Minnesota consisting of a touch screen and battery-backed microcontroller. Power was supplied by a 120 VAC to 12 VDC converter. An upgrade to the insulated cooler and microcontroller occurred in 2002, which was followed by proof of concept experimental pre-clinical transplants and tests demonstrating the efficacy of the device with isolated donor hearts. During the period between 2002 and 2006, a variety of donor organ containers were developed, modified, and tested to provide an optimal sterile environment and fluid path. Parallel development paths encompass formalized design specifications for final prototypes of the touch screen/microcontroller, organ container, and thermoelectric cooler.

  18. Human Fitting Studies of Cleveland Clinic Continuous-Flow Total Artificial Heart

    PubMed Central

    Karimov, Jamshid H.; Steffen, Robert J.; Byram, Nicole; Sunagawa, Gengo; Horvath, David; Cruz, Vincent; Golding, Leonard A.R.; Fukamachi, Kiyotaka; Moazami, Nader

    2015-01-01

    Implantation of mechanical circulatory support devices is challenging, especially in patients with a small chest cavity. We evaluated how well the Cleveland Clinic continuous-flow total artificial heart (CFTAH) fit the anatomy of patients about to receive a heart transplant. A mock pump model of the CFTAH was rapid-prototyped using biocompatible materials. The model was brought to the operative table, and the direction, length, and angulation of the inflow/outflow ports and outflow conduits were evaluated after the recipient's ventricles had been resected. Thoracic cavity measurements were based on preoperative computed tomographic data. The CFTAH fit well in all five patients (height, 170 ± 9 cm; weight, 75 ± 24 kg). Body surface area was 1.9 ± 0.3 m2 (range, 1.6-2.1 m2). The required inflow and outflow port orientation of both the left and right housings appeared consistent with the current version of the CFTAH implanted in calves. The left outflow conduit remained straight, but the right outflow direction necessitated a 73 ± 22 degree angulation to prevent potential kinking when crossing over the connected left outflow. These data support the fact that our design achieves the proper anatomical relationship of the CFTAH to a patient's native vessels. PMID:25806613

  19. Device therapy in the management of congestive heart failure.

    PubMed

    Turer, Aslan T; Rao, Sunil V

    2005-01-01

    Despite significant advancements in the treatment of heart failure over the past 2 decades, this patient population is still subject to considerably high morbidity and mortality rates. In recent years, the field of device therapy as adjunctive treatment to the medical management of congestive heart failure has grown in the wake of the large number of randomized trials that have demonstrated the safety and efficacy of these devices. The implantable defibrillator currently represents the standard of care in certain segments of the heart failure population, even in those without a prior arrhythmic event. Biventricular pacing systems appear to have a role in heart failure patients with prolongation of their QRS duration in improving ventricular performance and symptoms, if not mortality. Last, the shortage of organs available for orthotopic transplant has heightened interest in using ventricular-assist devices as destination therapy, and although there is evidence for the feasibility for this approach at the current time, there is a next generation of devices that appear even more promising.

  20. Ventricular assist device use in congenital heart disease with a comparison to heart transplant.

    PubMed

    Miller, Jacob R; Eghtesady, Pirooz

    2014-09-01

    Despite advances in medical and surgical therapies, some children with congenital heart disease (CHD) are not able to be adequately treated or palliated, leading them to develop progressive heart failure. As these patients progress to end-stage heart failure they pose a unique set of challenges. Heart transplant remains the standard of care; the donor pool, however, remains limited. Following the experience from the adult realm, the pediatric ventricular assist device (VAD) has emerged as a valid treatment option as a bridge to transplant. Due to the infrequent necessity and the uniqueness of each case, the pediatric VAD in the CHD population remains a topic with limited information. Given the experience in the adult realm, we were tasked with reviewing pediatric VADs and their use in patients with CHD and comparing this therapy to heart transplantation when possible.

  1. [Thermodynamic principles and physiologic criteria for the use of heat engines to drive the ventricles of an artificial heart].

    PubMed

    Kiselev, Iu M; Mordashev, V M; Osipov, A P; Shumakov, V I

    1990-01-01

    The authors review the thermodynamic bases and physiological limitations of the applicability of thermal engines for driving artificial heart ventricles. Show that the thermodynamic characteristics of Stirling and Brighton cycles do not make it possible to effectively use cycle-based engines in the artificial heart. A steam engine operating in accordance with the Rankine cycle may be regarded as an optimum type engine for that purpose. Demonstrate that according to the rules of physiology, use should be made of a separate driving of artificial heart ventricles by two independently operating steam engines. Provide the characteristics of the Soviet artificial heart "MIKRON" acceptable for implantation into the orthotopic position. PMID:2215181

  2. [Thermodynamic principles and physiologic criteria for the use of heat engines to drive the ventricles of an artificial heart].

    PubMed

    Kiselev, Iu M; Mordashev, V M; Osipov, A P; Shumakov, V I

    1990-01-01

    The authors review the thermodynamic bases and physiological limitations of the applicability of thermal engines for driving artificial heart ventricles. Show that the thermodynamic characteristics of Stirling and Brighton cycles do not make it possible to effectively use cycle-based engines in the artificial heart. A steam engine operating in accordance with the Rankine cycle may be regarded as an optimum type engine for that purpose. Demonstrate that according to the rules of physiology, use should be made of a separate driving of artificial heart ventricles by two independently operating steam engines. Provide the characteristics of the Soviet artificial heart "MIKRON" acceptable for implantation into the orthotopic position.

  3. Risk stratification in heart failure using artificial neural networks.

    PubMed Central

    Atienza, F.; Martinez-Alzamora, N.; De Velasco, J. A.; Dreiseitl, S.; Ohno-Machado, L.

    2000-01-01

    Accurate risk stratification of heart failure patients is critical to improve management and outcomes. Heart failure is a complex multisystem disease in which several predictors are categorical. Neural network models have successfully been applied to several medical classification problems. Using a simple neural network, we assessed one-year prognosis in 132 patients, consecutively admitted with heart failure, by classifying them in 3 groups: death, readmission and one-year event-free survival. Given the small number of cases, the neural network model was trained using a resampling method. We identified relevant predictors using the Automatic Relevance Determination (ARD) method, and estimated their mean effect on the 3 different outcomes. Only 9 individuals were misclassified. Neural networks have the potential to be a useful tool for making prognosis in the domain of heart failure. PMID:11079839

  4. Novel device-based interventional strategies for advanced heart failure

    PubMed Central

    Vanderheyden, Marc; Bartunek, Jozef

    2016-01-01

    While heart failure is one of the leading causes of mortality and morbidity, our tools to provide ultimate treatment solutions are still limited. Recent developments in new devices are designed to fill this therapeutic gap. The scope of this review is to focus on two particular targets, namely (1) left ventricular geometric restoration and (2) atrial depressurization. (1) Reduction of the wall stress by shrinking the ventricular cavity has been traditionally attempted surgically. Recently, the Parachute device (CardioKinetix Inc., Menlo Park, CA, USA) has been introduced to restore ventricular geometry and cardiac mechanics. The intervention aims to partition distal dysfunctional segments that are non-contributory to the ventricular mechanics and forward cardiac output. (2) Diastolic heart failure is characterized by abnormal relaxation and chamber stiffness. The main therapeutic goal achieved should be the reduction of afterload and diastolic pressure load. Recently, new catheter-based approaches were proposed to reduce left atrial pressure and ventricular decompression: the InterAtrial Shunt Device (IASD™) (Corvia Medical Inc., Tewksbury, MA, USA) and the V-Wave Shunt (V-Wave Ltd, Or Akiva, Israel). Both are designed to create a controlled atrial septal defect in symptomatic patients with heart failure. While the assist devices are aimed at end-stage heart failure, emerging device-based percutaneous or minimal invasive techniques comprise a wide spectrum of innovative concepts that target ventricular remodeling, cardiac contractility or neuro-humoral modulation. The clinical adoption is in the early stages of the initial feasibility and safety studies, and clinical evidence needs to be gathered in appropriately designed clinical trials. PMID:26966444

  5. Novel device-based interventional strategies for advanced heart failure.

    PubMed

    Toth, Gabor G; Vanderheyden, Marc; Bartunek, Jozef

    2016-01-01

    While heart failure is one of the leading causes of mortality and morbidity, our tools to provide ultimate treatment solutions are still limited. Recent developments in new devices are designed to fill this therapeutic gap. The scope of this review is to focus on two particular targets, namely (1) left ventricular geometric restoration and (2) atrial depressurization. (1) Reduction of the wall stress by shrinking the ventricular cavity has been traditionally attempted surgically. Recently, the Parachute device (CardioKinetix Inc., Menlo Park, CA, USA) has been introduced to restore ventricular geometry and cardiac mechanics. The intervention aims to partition distal dysfunctional segments that are non-contributory to the ventricular mechanics and forward cardiac output. (2) Diastolic heart failure is characterized by abnormal relaxation and chamber stiffness. The main therapeutic goal achieved should be the reduction of afterload and diastolic pressure load. Recently, new catheter-based approaches were proposed to reduce left atrial pressure and ventricular decompression: the InterAtrial Shunt Device (IASD™) (Corvia Medical Inc., Tewksbury, MA, USA) and the V-Wave Shunt (V-Wave Ltd, Or Akiva, Israel). Both are designed to create a controlled atrial septal defect in symptomatic patients with heart failure. While the assist devices are aimed at end-stage heart failure, emerging device-based percutaneous or minimal invasive techniques comprise a wide spectrum of innovative concepts that target ventricular remodeling, cardiac contractility or neuro-humoral modulation. The clinical adoption is in the early stages of the initial feasibility and safety studies, and clinical evidence needs to be gathered in appropriately designed clinical trials. PMID:26966444

  6. Application of Artificial Neural Networks in the Heart Electrical Axis Position Conclusion Modeling

    NASA Astrophysics Data System (ADS)

    Bakanovskaya, L. N.

    2016-08-01

    The article touches upon building of a heart electrical axis position conclusion model using an artificial neural network. The input signals of the neural network are the values of deflections Q, R and S; and the output signal is the value of the heart electrical axis position. Training of the network is carried out by the error propagation method. The test results allow concluding that the created neural network makes a conclusion with a high degree of accuracy.

  7. Upscaling cardiac assist devices in decompensated heart failure: Choice of device and its timing.

    PubMed

    Mishra, Sundeep

    2016-04-01

    Advanced heart failure is a heterogeneous condition unified by a very high mortality unless right treatment is instituted at the right time. The first step is understanding the mechanism leading to instability: hemodynamic or ischemic. Right kind of therapy; drugs (ionotropic) or IABP or other cardiac assist devices should be chosen according to mechanism of insult as well as degree of insult. Drugs such as ionotropes are effective only in very early course but if the decompensation has progressed beyond a certain point device such as IABP may be effective but again only early in the course when CPO? 0.6. Beyond a certain point, even IABP may not be effective: here only Impella (2.5, CP or 5) or Tandem Heart may be effective. However, beyond a certain point CPO<0.53, even these devices may not be effective. Thus crux of the matter is choice of a right device/drug and timing of its institution. PMID:27056646

  8. [Blood heat exchangers for the artificial heart using a radioisotope power source].

    PubMed

    Kiselev, Iu M; Trukhmanov, S B; Mosidze, T G; Kremnev, V A; Ponomarenko, T P

    1979-01-01

    A design of a vascular heat exchanger enabling it to establish in experiments with animals the degree of the possible specific-capacity thermal loads has been devised. The performance results may be taken account of in designing implantable appliances of assistive circulation and artificial heart. PMID:459782

  9. Design and construction of the artificial patient module for testing bioimpedance measuring devices

    NASA Astrophysics Data System (ADS)

    Młyńczak, Marcel; Pariaszewska, Katarzyna; Niewiadomski, Wiktor; Cybulski, Gerard

    2013-10-01

    The purpose of this study was to describe the design of the electronic module for testing bioimpedance measuring devices, for example impedance cardiographs or impedance pneumographs. Artificial Patient was conceived as an electronic equivalent of the impedance of skin-electrode interface and the impedance between electrodes - measured one. Different approaches in imitating a resistance of skin and an impedance of electrode-skin connection were presented. The module was adapted for frequently applied tetrapolar electrode configuration. Therefore the design do not enclose the elements simulating impedance between skin and receiver electrodes due to negligible effect of this impedance on the current flow through the receiver. The Artificial Patient enables testing either application generators, or receiver parts, particularly the level of noise and distortions of the signal. Use of digitally controlled potentiometer allows simulating different tissue resistances changes such as constant values, very-low-frequency and low-frequency changes corresponding to those caused by breathing or heart activity. Also it allows distorting signals in order to test algorithms of artifacts attenuation.

  10. [History, present and future of biomaterials used for artificial heart valves].

    PubMed

    Kostrzewa, Benita; Rybak, Zbigniew

    2013-01-01

    Artificial heart valves can be classified into mechanical and biological. We have three types of mechanical heart valves: caged ball, tilting disc and bileaflet. Mechanical heart valves are made from various materials. They may be produced from metals, ceramics and polymers, e.g.: stainless steel, titanium, silicone, pyrolytic carbon. Biological valves are made from synthetic components (e.g.: PTFE, Dacron) and materials of biological origin (e.g.: cow pericardium, pig heart valve). We have also identified transcatheter aortic valve implantation (TAVI). TAVI may be produced from metals, ceramics and polymers (e.g.: stainless steel, titanium, Dacron) and biological material (e.g.: pig heart valve). This paper describes advantages and disadvantages of different types of artificial heart valves. The lifespan of mechanical valves is 20-30 years and they can be used for patients of any age. Mechanical valves have also disadvantages--anticoagulants are required to prevent thrombosis. Biological valves are made from natural materials, so they do not require prolonged anticoagulation. Their lifetime is 10-15 years, so they are offered to patients over 40 years. Another problem is the occurrence of calcification.

  11. Simulation of blood flow through an artificial heart

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin; Chang, I-Dee; Rogers, Stuart E.; Kwak, Dochan

    1991-01-01

    A numerical simulation of the incompressible viscous flow through a prosthetic tilting disk heart valve is presented in order to demonstrate the current capability to model unsteady flows with moving boundaries. Both steady state and unsteady flow calculations are done by solving the incompressible Navier-Stokes equations in 3-D generalized curvilinear coordinates. In order to handle the moving boundary problems, the chimera grid embedding scheme which decomposes a complex computational domain into several simple subdomains is used. An algebraic turbulence model for internal flows is incorporated to reach the physiological values of Reynolds number. Good agreement is obtained between the numerical results and experimental measurements. It is found that the tilting disk valve causes large regions of separated flow, and regions of high shear.

  12. Simulation of a pulsatile total artificial heart: Development of a partitioned Fluid Structure Interaction model

    NASA Astrophysics Data System (ADS)

    Sonntag, Simon J.; Kaufmann, Tim A. S.; Büsen, Martin R.; Laumen, Marco; Linde, Torsten; Schmitz-Rode, Thomas; Steinseifer, Ulrich

    2013-04-01

    Heart disease is one of the leading causes of death in the world. Due to a shortage in donor organs artificial hearts can be a bridge to transplantation or even serve as a destination therapy for patients with terminal heart insufficiency. A pusher plate driven pulsatile membrane pump, the Total Artificial Heart (TAH) ReinHeart, is currently under development at the Institute of Applied Medical Engineering of RWTH Aachen University.This paper presents the methodology of a fully coupled three-dimensional time-dependent Fluid Structure Interaction (FSI) simulation of the TAH using a commercial partitioned block-Gauss-Seidel coupling package. Partitioned coupling of the incompressible fluid with the slender flexible membrane as well as a high fluid/structure density ratio of about unity led inherently to a deterioration of the stability (‘artificial added mass instability’). The objective was to conduct a stable simulation with high accuracy of the pumping process. In order to achieve stability, a combined resistance and pressure outlet boundary condition as well as the interface artificial compressibility method was applied. An analysis of the contact algorithm and turbulence condition is presented. Independence tests are performed for the structural and the fluid mesh, the time step size and the number of pulse cycles. Because of the large deformation of the fluid domain, a variable mesh stiffness depending on certain mesh properties was specified for the fluid elements. Adaptive remeshing was avoided. Different approaches for the mesh stiffness function are compared with respect to convergence, preservation of mesh topology and mesh quality. The resulting mesh aspect ratios, mesh expansion factors and mesh orthogonalities are evaluated in detail. The membrane motion and flow distribution of the coupled simulations are compared with a top-view recording and stereo Particle Image Velocimetry (PIV) measurements, respectively, of the actual pump.

  13. Assessing the resistance to calcification of polyurethane membranes used in the manufacture of ventricles for a totally implantable artificial heart.

    PubMed

    Yang, M; Zhang, Z; Hahn, C; King, M W; Guidoin, R

    1999-01-01

    Ventricles made from segmented polyurethane membranes and used in the fabrication of a totally implantable artificial heart are known to undergo biomaterial-associated calcification. As there is no effective method currently available to prevent such biomaterials from calcifying, a practical solution is to use only materials with a relatively high resistance to calcification, to extend ventricular durability and ensure a longer functional life for the manufactured device. In the present study, an in vitro calcification protocol was used to determine the relative resistance to calcification of six different polyurethanes, namely, Carbothane PC3570A, Chronoflex AR, Corethane 80A, Corethane 55D, Tecoflex EG80A, and Tecothane TT1074A. The results demonstrated that all six polyurethanes did become calcified during the 60-day incubation period in the calcification solution. The degree of calcification was found to be associated with the surface chemistry of the particular polyurethane, with the Tecothane TT1074A exhibiting the highest level. The Corethane 80A and 55D polymers showed a relatively low propensity to calcify. These two membranes can, therefore, be considered as the most appropriate materials for the fabrication of ventricles for a totally implantable artificial heart. In addition, since the calcification occurred primarily at the surface of the membranes, without affecting the bulk microphase structure, the issue of modifying the surface chemistry to reduce the incidence of calcification is discussed. PMID:10490678

  14. INTRACORPOREAL HEAT DISSIPATION FROM A RADIOISOTOPE-POWERED ARTIFICIAL HEART.

    PubMed

    Huffman, Fred N.; Hagen, Kenneth G.; Whalen, Robert L.; Fuqua, John M.; Norman, John C.

    1974-01-01

    The feasibility of radioisotope-fueled circulatory support systems depends on the ability of the body to dissipate the reject heat from the power source driving the blood pump as well as to tolerate chronic intracorporeal radiation. Our studies have focused on the use of the circulating blood as a heat sink. Initial in vivo heat transfer studies utilized straight tube heat exchangers (electrically and radioisotope energized) to replace a segment of the descending aorta. More recent studies have used a left ventricular assist pump as a blood-cooled heat exchanger. This approach minimizes trauma, does not increase the area of prosthetic interface with the blood, and minimizes system volume. Heat rejected from the thermal engine (vapor or gas cycle) is transported from the nuclear power source in the abdomen to the pump in the thoracic cavity via hydraulic lines. Adjacent tissue is protected from the fuel capsule temperature (900 to 1200 degrees F) by vacuum foil insulation and polyurethane foam. The in vivo thermal management problems have been studied using a simulated thermal system (STS) which approximates the heat rejection and thermal transport mechanisms of the nuclear circulatory support systems under development by NHLI. Electric heaters simulate the reject heat from the thermal engines. These studies have been essential in establishing the location, suspension, surgical procedures, and postoperative care for implanting prototype nuclear heart assist systems in calves. The pump has a thermal impedance of 0.12 degrees C/watt. Analysis of the STS data in terms of an electrical analog model implies a heat transfer coefficient of 4.7 x 10(-3) watt/cm(2) degrees C in the abdomen compared to a value of 14.9 x 10(-3) watt/cm(2) degrees C from the heat exchanger plenum into the diaphragm.

  15. INTRACORPOREAL HEAT DISSIPATION FROM A RADIOISOTOPE-POWERED ARTIFICIAL HEART

    PubMed Central

    Huffman, Fred N.; Hagen, Kenneth G.; Whalen, Robert L.; Fuqua, John M.; Norman, John C.

    1974-01-01

    The feasibility of radioisotope-fueled circulatory support systems depends on the ability of the body to dissipate the reject heat from the power source driving the blood pump as well as to tolerate chronic intracorporeal radiation. Our studies have focused on the use of the circulating blood as a heat sink. Initial in vivo heat transfer studies utilized straight tube heat exchangers (electrically and radioisotope energized) to replace a segment of the descending aorta. More recent studies have used a left ventricular assist pump as a blood-cooled heat exchanger. This approach minimizes trauma, does not increase the area of prosthetic interface with the blood, and minimizes system volume. Heat rejected from the thermal engine (vapor or gas cycle) is transported from the nuclear power source in the abdomen to the pump in the thoracic cavity via hydraulic lines. Adjacent tissue is protected from the fuel capsule temperature (900 to 1200°F) by vacuum foil insulation and polyurethane foam. The in vivo thermal management problems have been studied using a simulated thermal system (STS) which approximates the heat rejection and thermal transport mechanisms of the nuclear circulatory support systems under development by NHLI. Electric heaters simulate the reject heat from the thermal engines. These studies have been essential in establishing the location, suspension, surgical procedures, and postoperative care for implanting prototype nuclear heart assist systems in calves. The pump has a thermal impedance of 0.12°C/watt. Analysis of the STS data in terms of an electrical analog model implies a heat transfer coefficient of 4.7 × 10−3 watt/cm2°C in the abdomen compared to a value of 14.9 × 10−3 watt/cm2°C from the heat exchanger plenum into the diaphragm. Images PMID:15215968

  16. Construction of an artificial heart pump performance test system.

    PubMed

    Liu, Yingjie; Allaire, Paul; Wu, Yi; Wood, Houston; Olsen, Don

    2006-12-01

    A hydraulic loop, which simulates pressure/flow response of the human circulatory system, is needed to bench test the various versions of rotary left ventricular assist devices (LVADs). This article describes the design of such a loop and the simulated response of different physiological states, such as a healthy person in sleep, rest, and mild physical activity, and in different pathological states. The loop consists of: (1) pulsatile left and right cardiac simulators; (2) air/water tanks to model the venous and arterial compliances; (3) tygon tubes to model the venous, arterial, and other system flow resistances; and (4) a tuning clamp to model the variation in system resistance characteristics under different cardiac pressure/flow conditions. The simulated responses were compared to the data found in the literature to validate the loop performance prior to LVAD testing. PMID:17136597

  17. Suturing-Free Artificial Dura with Dacron Heart Patch in Decompressive Craniectomy and Cranioplasty.

    PubMed

    Wang, Fei; Xue, Yan; Zhao, Si-Shun; Yang, Ting-Jian; Song, Hao-Qing; Liu, Hong

    2015-12-01

    Dacron heart patch has been used in decompressive craniectomy, performing the function of septa, mainly to prevent extra adhesion of temporal muscle and decompressive meningeal adhesion in the second-stage cranioplasty, so as to make the operation easier. Then, we made the following modification technology: (1) We used artificial suturing-free dura participate directly in the duraplasty. (2) Dacron patch is not in need of trimming the side holes and can directly cover the decompression window. From March 2012 to October 2013, we applied the technology of artificial dura with Dacron heart patch in 23 patients; after operation, we found that the initial depressive craniectomy cost less time, due to the tension-reduced suture which was not needed, and in the second-stage cranioplasty, the temporal was easy to remove and had no adhesion with the Dacron patch, so as to reach temporal muscle anatomy preservation, and with no obvious postoperative complication. PMID:27011500

  18. A new control method depending on primary phase angle of transcutaneous energy transmission system for artificial heart.

    PubMed

    Miura, H; Saito, I; Sato, F; Shiraishi, Y; Yambe, T; Matsuki, H

    2013-01-01

    A new control method for stabilizing output voltage of the transcutaneous energy transmission system for artificial heart is proposed. This method is primary side, is outside of the body, which is not depending on a signal transmission system from the implanted device. The impedance observed from primary side changes from inductive to capacitive and the output voltage decreases drastically when the output current is large and the coupling factor is higher than that of the optimal condition. In this case, the driving frequency should be changed to higher so that the phase angle of the primary impedance is zero degree. The preliminary examination showed that this control method can enhance the output voltage limit to twice and the feasibility of the primary side control.

  19. Evaluation of the inner-surface morphology of an artificial heart by acoustic microscopy.

    PubMed

    Saijo, Y; Okawai, H; Sasaki, H; Yambe, T; Nitta, S; Tanaka, M; Kobayashi, K; Honda, Y

    2000-01-01

    The total artificial heart (TAH) is being developed for permanent replacement of the natural heart instead of heart transplantation. The need for detecting the material fatigue in the TAH is increasing in order to guarantee long-term use. In this study, the inner surface morphology of the TAH was evaluated by a specially developed scanning acoustic microscope (SAM) system operating in the frequency range of 100-200 MHz. The inner sac of our TAH consisted of polyvinylchloride coated with polyurethane, and the SAM investigations were performed before and after the implantations in goats. The amplitude images of the SAM demonstrated protein adhesion on the inner surface of the TAH after the animal experiment, and the phase images showed distortion of the wall with spatial resolution of 0.2 microm. These results suggest the feasibility of a high-frequency ultrasound for evaluating the material fatigue of TAH.

  20. Device therapy to modulate the autonomic nervous system to treat heart failure.

    PubMed

    Lopshire, John C; Zipes, Douglas P

    2012-10-01

    Heart failure is the final common pathway in many forms of heart disease, and is associated with excessive morbidity and mortality. Pathophysiologic alterations in the interaction between the heart and the autonomic nervous system in advanced heart failure have been noted for decades. Over the last decade, great advances have been made in the medical and surgical treatment of heart failure - and some of these modalities target the neuro-cardiac axis. Despite these advances, many patients progress to end-stage heart failure and death. Recently, device-based therapy targeting the neuro-cardiac axis with various forms of neuromodulatory stimuli has been shown to improve heart function in experimental heart failure models. These include spinal cord stimulation, vagal nerve stimulation, and baroreflex modulation. Human trials are now underway to evaluate the safety and efficacy of these device-based neuromodulatory modalities in the heart failure population.

  1. Ventricular assist devices for treatment of acute heart failure and chronic heart failure.

    PubMed

    Kirkpatrick, James N; Wieselthaler, Georg; Strueber, Martin; St John Sutton, Martin G; Rame, J Eduardo

    2015-07-01

    Despite therapeutic advances that improve longevity and quality of life, heart failure (HF) remains a relentless disease. At the end stage of HF, patients may become eligible for mechanical circulatory support (MCS) for the indications of stabilising acute cardiogenic shock or for chronic HF management. MCS use is growing rapidly in the USA and some countries of the European Union, especially in transplant-ineligible patients. In others, it remains largely a tool to stabilise patients until heart transplant. MCS comprises a heterogeneous group of temporary and durable devices which augment or replace the pumping function of one or both ventricles, with postimplant 2 year survival rivalling that of transplant in selected, lower-risk patients. In transplant-eligible and non-transplant-eligible patients, improvement in end-organ perfusion, functional capacity and quality of life have been noted. Even for optimal candidates, however, there are a host of potential complications that require constant vigilance of a coordinated care team. Recently, there has been official recognition of the importance of palliative care expertise in advance care planning preimplant and management of patients with ventricular assist devices at the end of their lives. PMID:25948420

  2. Cutting the fat: artificial muscle oscillators for lighter, cheaper, and slimmer devices

    NASA Astrophysics Data System (ADS)

    O'Brien, Benjamin M.; Rosset, Samuel; Shea, Herbert R.; Anderson, Iain A.

    2012-04-01

    Artificial muscles based on dielectric elastomers show enormous promise for a wide range of applications and are slowly moving from the lab to industry. One problem for industrial uptake is the expensive, rigid, heavy and bulky high voltage driver, sensor and control circuitry that artificial muscle devices currently require. One recent development, the Dielectric Elastomer Switch(es) (DES), shows promise for substantially reducing auxiliary circuitry and helping to mature the technology. DES are piezoresistive elements that can be used to form logic, driver, and sensor circuitry. One particularly useful feature of DES is their ability to embed oscillatory behaviour directly into an artificial muscle device. In this paper we will focus on how DES oscillators can break down the barriers to industrial adoption for artificial muscle devices. We have developed an improved artificial muscle ring oscillator and applied it to form a mechanosensitive conveyor. The free running oscillator ran at 4.4 Hz for 1056 cycles before failing due to electrode degradation. With better materials artificial muscle oscillators could open the door to robots with increased power to weight ratios, simple-to-control peristaltic pumps, and commercially viable artificial muscle motors.

  3. Numerical model of full-cardiac cycle hemodynamics in a total artificial heart and the effect of its size on platelet activation.

    PubMed

    Marom, Gil; Chiu, Wei-Che; Crosby, Jessica R; DeCook, Katrina J; Prabhakar, Saurabh; Horner, Marc; Slepian, Marvin J; Bluestein, Danny

    2014-12-01

    The SynCardia total artificial heart (TAH) is the only Food and Drug Administration (FDA) approved device for replacing hearts in patients with congestive heart failure. It pumps blood via pneumatically driven diaphragms and controls the flow with mechanical valves. While it has been successfully implanted in more than 1300 patients, its size precludes implantation in smaller patients. This study's aim was to evaluate the viability of scaled-down TAHs by quantifying thrombogenic potentials from flow patterns. Simulations of systole were first conducted with stationary valves, followed by an advanced full-cardiac cycle model with moving valves. All the models included deforming diaphragms and platelet suspension in the blood flow. Flow stress accumulations were computed for the platelet trajectories and thrombogenic potentials were assessed. The simulations successfully captured complex flow patterns during various phases of the cardiac cycle. Increased stress accumulations, but within the safety margin of acceptable thrombogenicity, were found in smaller TAHs, indicating that they are clinically viable.

  4. [Thermoregulating devices for artificial circulation apparatus with thermoelectric elements].

    PubMed

    Efremov, A A; Andrushchenko, L I

    1981-01-01

    The increase of the absolute capacity of temperature control devices used in extracorporeal blood circulation apparatus has necessitated the intensification of heat exchange and, as a consequence, the work of heat exchangers under anisothermal conditions. This concerns mainly thermoelectric temperature control devices. Calculations in the process of their design and, to a greater extent, the optimization of their parameters under the conditions of anisothermality in the soldered joints become far more complicated. The numerical analysis of such thermoelectric device with anisothermal soldered joints has demonstrated the possibility of its analytical optimization by assuming it to be a thermoelectric device working under the average effective values of temperature and the coefficients of electrical characteristics. The results thus obtained allow to considerably decrease labor consumption in designing the above-mentioned devices. PMID:7207094

  5. Polymeric heart valves for surgical implantation, catheter-based technologies and heart assist devices.

    PubMed

    Bezuidenhout, Deon; Williams, David F; Zilla, Peter

    2015-01-01

    Efficient function and long-term durability without the need for anticoagulation, coupled with the ability to be accommodated in many different types of patient, are the principal requirements of replacement heart valves. Although the clinical use of valves appeared to have remained steady for several decades, the evolving demands for the elderly and frail patients typically encountered in the developed world, and the needs of much younger and poorer rheumatic heart disease patients in the developing world have now necessitated new paradigms for heart valve technologies and associated materials. This includes further consideration of durable elastomeric materials. The use of polymers to produce flexible leaflet valves that have the benefits of current commercial bioprosthetic and mechanical valves without any of their deficiencies has been held desirable since the mid 1950s. Much attention has been focused on thermoplastic polyurethanes in view of their generally good physico-chemical properties and versatility in processing, coupled with the improving biocompatibility and stability of recent formulations. Accelerated in vitro durability of between 600 and 1000 million cycles has been achieved using polycarbonate urethanes, and good resistance to degradation, calcification and thrombosis in vivo has been shown with some polysiloxane-based polyurethanes. Nevertheless, polymeric valves have remained relegated to use in temporary ventricular assist devices for bridging heart failure patients to transplantation. Some recent studies suggest that there is a greater degree of instability in thermoplastic materials than hitherto believed so that significant challenges remain in the search for the combination of durability and biocompatibility that would allow polymeric valves to become a clinical reality for surgical implantation. Perhaps more importantly, they could become candidates for use in situations where minimally invasive transcatheter procedures are used to

  6. Disease management: remote monitoring in heart failure patients with implantable defibrillators, resynchronization devices, and haemodynamic monitors.

    PubMed

    Abraham, William T

    2013-06-01

    Heart failure represents a major public health concern, associated with high rates of morbidity and mortality. A particular focus of contemporary heart failure management is reduction of hospital admission and readmission rates. While optimal medical therapy favourably impacts the natural history of the disease, devices such as cardiac resynchronization therapy devices and implantable cardioverter defibrillators have added incremental value in improving heart failure outcomes. These devices also enable remote patient monitoring via device-based diagnostics. Device-based measurement of physiological parameters, such as intrathoracic impedance and heart rate variability, provide a means to assess risk of worsening heart failure and the possibility of future hospitalization. Beyond this capability, implantable haemodynamic monitors have the potential to direct day-to-day management of heart failure patients to significantly reduce hospitalization rates. The use of a pulmonary artery pressure measurement system has been shown to significantly reduce the risk of heart failure hospitalization in a large randomized controlled study, the CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients (CHAMPION) trial. Observations from a pilot study also support the potential use of a left atrial pressure monitoring system and physician-directed patient self-management paradigm; these observations are under further investigation in the ongoing LAPTOP-HF trial. All these devices depend upon high-intensity remote monitoring for successful detection of parameter deviations and for directing and following therapy.

  7. Artificial eggs: measuring heart rate and effects of disturbance in nesting penguins.

    PubMed

    Nimon, A J; Schroter, R C; Oxenham, R K

    1996-09-01

    A technique for the noninvasive measurement of heart rate in incubating penguins is described and evaluated. The technique uses an artificial egg fitted with an infrared sensor. Placing the egg in the nest causes minimal disturbance to the resident penguin; this penguin is then paint-marked so that subsequent measurements may be taken from the unmarked, naive partner once it assumes incubation. Heart rate changes are useful indicators of nesting penguins' reactions to events in their environment because often their behaviour does not appear to vary in response to a threat until the point at which they flee, exposing eggs and chicks to predators. The eggs can be readily transferred from one nest to another. They have been successfully deployed on both African (Spheniscus demersus) and Gentoo Penguins (Pygoscelis papua). The design should be readily adaptable for use with other seabirds and passerines. PMID:8873285

  8. Artificial eggs: measuring heart rate and effects of disturbance in nesting penguins.

    PubMed

    Nimon, A J; Schroter, R C; Oxenham, R K

    1996-09-01

    A technique for the noninvasive measurement of heart rate in incubating penguins is described and evaluated. The technique uses an artificial egg fitted with an infrared sensor. Placing the egg in the nest causes minimal disturbance to the resident penguin; this penguin is then paint-marked so that subsequent measurements may be taken from the unmarked, naive partner once it assumes incubation. Heart rate changes are useful indicators of nesting penguins' reactions to events in their environment because often their behaviour does not appear to vary in response to a threat until the point at which they flee, exposing eggs and chicks to predators. The eggs can be readily transferred from one nest to another. They have been successfully deployed on both African (Spheniscus demersus) and Gentoo Penguins (Pygoscelis papua). The design should be readily adaptable for use with other seabirds and passerines.

  9. [Artificial heart--turbo type blood pump for long-term use].

    PubMed

    Akamatsu, Teruaki

    2003-05-01

    Shortage of donor heart for transplantation necessitates long-term artificial assist heart. Turbo-pump is smaller, simpler and cheaper than the pulsatile displacement type pump, but the turbo-pump has defect of thrombus formation at the shaft seal. Our centrifugal pump with magnetically suspended impellers overcomes this defect and is ready for clinical trials now. The structures and functions are described and are compared with the other newly-developed pump of the same kinds with us. And also the pumps of centrifugal type and axial-type, of which impellers are supported by pivots, are reviewed briefly from the stand point for long-term use. Other pumps are referred too: pumps with hydrodynamic bearing and a pump with the shaft seal which is washed and cooled by saline solution.

  10. 3D Printing to Guide Ventricular Assist Device Placement in Adults With Congenital Heart Disease and Heart Failure.

    PubMed

    Farooqi, Kanwal M; Saeed, Omar; Zaidi, Ali; Sanz, Javier; Nielsen, James C; Hsu, Daphne T; Jorde, Ulrich P

    2016-04-01

    As the population of adults with congenital heart disease continues to grow, so does the number of these patients with heart failure. Ventricular assist devices are underutilized in adults with congenital heart disease due to their complex anatomic arrangements and physiology. Advanced imaging techniques that may increase the utilization of mechanical circulatory support in this population must be explored. Three-dimensional printing offers individualized structural models that would enable pre-surgical planning of cannula and device placement in adults with congenital cardiac disease and heart failure who are candidates for such therapies. We present a review of relevant cardiac anomalies, cases in which such models could be utilized, and some background on the cost and procedure associated with this process. PMID:27033018

  11. Investigating the functionality of diamond-like carbon films on an artificial heart diaphragm.

    PubMed

    Ohgoe, Yasuharu; Takada, Satoshi; Hirakuri, Kenji K; Tsuchimoto, Katsuya; Homma, Akihiko; Miyamatsu, Toshinobu; Saitou, Tomoyuki; Friedbacher, Gernot; Tatsumi, Eisuke; Taenaka, Yoshiyuki; Fukui, Yasuhiro

    2003-01-01

    In this study, the authors used diamond-like carbon film to coat the ellipsoidal diaphragm (polyurethane elastomer) of artificial hearts. The purpose of such coatings is to prevent the penetration of hydraulic silicone oil and blood through the diaphragm. To attach diamond-like carbon film uniformly on the diaphragm, the authors developed a special electrode. In estimating the uniformity of the diamond-like carbon film, the thickness was measured using a scanning electron microscope, and the characteristics of the diamond-like carbon film was investigated using infrared spectroscopy, Ar-laser Raman spectrophotometer, and x-ray photoelectron spectrometer. Also, to estimate the penetration of silicone oil through the diaphragm, in vitro testing was operated by alternating the pressure of silicone oil for 20 days. The authors were able to successfully attach uniform deposition of diamond-like carbon film on the ellipsoidal diaphragm. In this in vitro test, diamond-like carbon film was proven to have good stability. The amount of silicone oil penetration was improved by one-third using the diamond-like carbon film coating compared with an uncoated diaphragm. It is expected that through the use of the diamond-like carbon film, the dynamic compatibility of an artificial heart diaphragm will increase.

  12. Measurement and reconstruction of the leaflet geometry for a pericardial artificial heart valve.

    PubMed

    Jiang, Hongjun; Campbell, Gord; Xi, Fengfeng

    2005-03-01

    This paper describes the measurement and reconstruction of the leaflet geometry for a pericardial heart valve. Tasks involved include mapping the leaflet geometries by laser digitizing and reconstructing the 3D freeform leaflet surface based on a laser scanned profile. The challenge is to design a prosthetic valve that maximizes the benefits offered to the recipient as compared to the normally operating naturally-occurring valve. This research was prompted by the fact that artificial heart valve bioprostheses do not provide long life durability comparable to the natural heart valve, together with the anticipated benefits associated with defining the valve geometries, especially the leaflet geometries for the bioprosthetic and human valves, in order to create a replicate valve fabricated from synthetic materials. Our method applies the concept of reverse engineering in order to reconstruct the freeform surface geometry. A Brown & Shape coordinate measuring machine (CMM) equipped with a HyMARC laser-digitizing system was used to measure the leaflet profiles of a Baxter Carpentier-Edwards pericardial heart valve. The computer software, Polyworks was used to pre-process the raw data obtained from the scanning, which included merging images, eliminating duplicate points, and adding interpolated points. Three methods, creating a mesh model from cloud points, creating a freeform surface from cloud points, and generating a freeform surface by B-splines are presented in this paper to reconstruct the freeform leaflet surface. The mesh model created using Polyworks can be used for rapid prototyping and visualization. To fit a freeform surface to cloud points is straightforward but the rendering of a smooth surface is usually unpredictable. A surface fitted by a group of B-splines fitted to cloud points was found to be much smoother. This method offers the possibility of manually adjusting the surface curvature, locally. However, the process is complex and requires additional

  13. Control and driving of pneumatic total artificial hearts TNS-BRNO-II and -III in long-term experiments.

    PubMed

    Vasků, J; Urbánek, P; Vasků, J; Cerný, J; Smutný, M; Urbánek, E; Suchánek, J; Gregor, Z; Dostál, M; Guba, P

    1986-04-01

    Hemodynamic analysis was carried out during long-term experiments with the pneumatic total artificial hearts TNS-BRNO-II and TNS-BRNO-III to determine standard methods of starting artificial hearts and criteria for their long-term operation in vivo. In long-term experiments, regulatory mechanisms automatically regulating the systole length and diastolic aspiration pressure have also been verified. Comparison of hemodynamic variables obtained from invasive measurements with pneumatic pressure curves permitted the control and monitoring of the experiment in its entirety by noninvasive methods only. The control of the artificial heart using the Chirasist TN 3 and Chirasist TN 4 was adapted to specific properties of the pumps, above all to the functions of the atypical inlet valves. The terminal stages of the experiments have shown that a 100-ml pump can ensure survival of experimental calves up to 210 kg body weight.

  14. First clinical application of the DuraHeart centrifugal ventricular assist device for a Japanese patient.

    PubMed

    Yoshitake, Isamu; El-Banayosy, Aly; Yoda, Masataka; Hata, Mitsumasa; Sezai, Akira; Niino, Tetsuya; Wakui, Shinji; Koerfer, Reiner; Minami, Kazutomo

    2009-09-01

    The DuraHeart ventricular assist device (VAD) is a third-generation implantable centrifugal pump with a magnetically levitated impeller. Since February 2007, the device has been clinically applied with excellent results as a bridge to heart transplantation in Europe. As of this writing, however, the device has yet to be approved by the Ministry of Health, Labour and Welfare for clinical use in Japan. We herein report the first clinical application of this device for a Japanese patient. A 31-year-old man with dilated cardiomyopathy was transferred to the Heart and Diabetes Center NRW (HDZ-NRW) in Bad Oeynhausen, Germany, where he was to await heart transplantation. The transfer was safely completed under management with low-dose dopamine. His condition gradually deteriorated at HDZ-NRW, and the DuraHeart left ventricular assist device was implanted for the left ventricle at 7 weeks after admission. Shortly thereafter, however, on POD 7, a Thoratec VAD had to be inserted on the right side due to refractory right heart failure. The right ventricular assist device could be explanted after a 3-month assist, and the patient is now waiting for heart transplantation at home in Germany.

  15. Ultra-flexible Piezoelectric Devices Integrated with Heart to Harvest the Biomechanical Energy

    PubMed Central

    Lu, Bingwei; Chen, Ying; Ou, Dapeng; Chen, Hang; Diao, Liwei; Zhang, Wei; Zheng, Jun; Ma, Weiguo; Sun, Lizhong; Feng, Xue

    2015-01-01

    Power supply for medical implantable devices (i.e. pacemaker) always challenges not only the surgery but also the battery technology. Here, we report a strategy for energy harvesting from the heart motion by using ultra-flexible piezoelectric device based on lead zirconate titanate (PZT) ceramics that has most excellent piezoelectricity in commercial materials, without any burden or damage to hearts. Experimental swine are selected for in vivo test with different settings, i.e. opened chest, close chest and awake from anesthesia, to simulate the scenario of application in body due to their hearts similar to human. The results show the peak-to-peak voltage can reach as high as 3 V when the ultra-flexible piezoelectric device is fixed from left ventricular apex to right ventricle. This demonstrates the possibility and feasibility of fully using the biomechanical energy from heart motion in human body for sustainably driving implantable devices. PMID:26538375

  16. Ultra-flexible Piezoelectric Devices Integrated with Heart to Harvest the Biomechanical Energy.

    PubMed

    Lu, Bingwei; Chen, Ying; Ou, Dapeng; Chen, Hang; Diao, Liwei; Zhang, Wei; Zheng, Jun; Ma, Weiguo; Sun, Lizhong; Feng, Xue

    2015-11-05

    Power supply for medical implantable devices (i.e. pacemaker) always challenges not only the surgery but also the battery technology. Here, we report a strategy for energy harvesting from the heart motion by using ultra-flexible piezoelectric device based on lead zirconate titanate (PZT) ceramics that has most excellent piezoelectricity in commercial materials, without any burden or damage to hearts. Experimental swine are selected for in vivo test with different settings, i.e. opened chest, close chest and awake from anesthesia, to simulate the scenario of application in body due to their hearts similar to human. The results show the peak-to-peak voltage can reach as high as 3 V when the ultra-flexible piezoelectric device is fixed from left ventricular apex to right ventricle. This demonstrates the possibility and feasibility of fully using the biomechanical energy from heart motion in human body for sustainably driving implantable devices.

  17. Ultra-flexible Piezoelectric Devices Integrated with Heart to Harvest the Biomechanical Energy

    NASA Astrophysics Data System (ADS)

    Lu, Bingwei; Chen, Ying; Ou, Dapeng; Chen, Hang; Diao, Liwei; Zhang, Wei; Zheng, Jun; Ma, Weiguo; Sun, Lizhong; Feng, Xue

    2015-11-01

    Power supply for medical implantable devices (i.e. pacemaker) always challenges not only the surgery but also the battery technology. Here, we report a strategy for energy harvesting from the heart motion by using ultra-flexible piezoelectric device based on lead zirconate titanate (PZT) ceramics that has most excellent piezoelectricity in commercial materials, without any burden or damage to hearts. Experimental swine are selected for in vivo test with different settings, i.e. opened chest, close chest and awake from anesthesia, to simulate the scenario of application in body due to their hearts similar to human. The results show the peak-to-peak voltage can reach as high as 3 V when the ultra-flexible piezoelectric device is fixed from left ventricular apex to right ventricle. This demonstrates the possibility and feasibility of fully using the biomechanical energy from heart motion in human body for sustainably driving implantable devices.

  18. Orthotopic heart transplant versus left ventricular assist device: A national comparison of cost and survival

    PubMed Central

    Mulloy, Daniel P.; Bhamidipati, Castigliano M.; Stone, Matthew L.; Ailawadi, Gorav; Kron, Irving L.; Kern, John A.

    2012-01-01

    Objectives Orthotopic heart transplantation is the standard of care for end-stage heart disease. Left ventricular assist device implantation offers an alternative treatment approach. Left ventricular assist device practice has changed dramatically since the 2008 Food and Drug Administration approval of the HeartMate II (Thoratec, Pleasanton, Calif), but at what societal cost? The present study examined the cost and efficacy of both treatments over time. Methods All patients who underwent either orthotopic heart transplantation (n = 9369) or placement of an implantable left ventricular assist device (n = 6414) from 2005 to 2009 in the Nationwide Inpatient Sample were selected. The trends in treatment use, mortality, and cost were analyzed. Results The incidence of orthotopic heart transplantation increased marginally within a 5-year period. In contrast, the annual left ventricular assist device implantation rates nearly tripled. In-hospital mortality from left ventricular assist device implantation decreased precipitously, from 42% to 17%. In-hospital mortality for orthotopic heart transplantation remained relatively stable (range, 3.8%–6.5%). The mean cost per patient increased for both orthotopic heart transplantation and left ventricular assist device placement (40% and 17%, respectively). With the observed increase in both device usage and cost per patient, the cumulative Left ventricular assist device cost increased 232% within 5 years (from $143 million to $479 million). By 2009, Medicare and Medicaid were the primary payers for nearly one half of all patients (orthotopic heart transplantation, 45%; left ventricular assist device, 51%). Conclusions Since Food and Drug Administration approval of the HeartMate II, mortality after left ventricular assist device implantation has decreased rapidly, yet has remained greater than that after orthotopic heart transplantation. The left ventricular assist device costs have continued to increase and have been

  19. Three-dimentional simulation of flow-induced platelet activation in artificial heart valves

    NASA Astrophysics Data System (ADS)

    Hedayat, Mohammadali; Asgharzadeh, Hafez; Borazjani, Iman

    2015-11-01

    Since the advent of heart valve, several valve types such as mechanical and bio-prosthetic valves have been designed. Mechanical Heart Valves (MHV) are durable but suffer from thromboembolic complications that caused by shear-induced platelet activation near the valve region. Bio-prosthetic Heart Valves (BHV) are known for better hemodynamics. However, they usually have a short average life time. Realistic simulations of heart valves in combination with platelet activation models can lead to a better understanding of the potential risk of thrombus formation in such devices. In this study, an Eulerian approach is developed to calculate the platelet activation in three-dimensional simulations of flow through MHV and BHV using a parallel overset-curvilinear immersed boundary technique. A curvilinear body-fitted grid is used for the flow simulation through the anatomic aorta, while the sharp-interface immersed boundary method is used for simulation of the Left Ventricle (LV) with prescribed motion. In addition, dynamics of valves were calculated numerically using under-relaxed strong-coupling algorithm. Finally, the platelet activation results for BMV and MHV are compared with each other.

  20. Fabrication and assembly of MEMS accelerometer-based heart monitoring device with simplified, one step placement.

    PubMed

    Tjulkins, Fjodors; Nguyen, Anh-Tuan Thai; Andreassen, Erik; Aasmundtveit, Knut; Hoivik, Nils; Hoff, Lars; Halvorsen, Per Steinar; Grymyr, Ole-Johannes; Imenes, Kristin

    2015-01-01

    An accelerometer-based heart monitoring system has been developed for real-time evaluation of heart wall movement. In this paper, assembly and fabrication of an improved device is presented along with system characterization and test data from an animal experiment. The new device is smaller and has simplified the implantation procedure compared to earlier prototypes. Leakage current recordings were well below those set by the corresponding standards. PMID:25429874

  1. Artificial Synaptic Devices Based on Natural Chicken Albumen Coupled Electric-Double-Layer Transistors

    PubMed Central

    Wu, Guodong; Feng, Ping; Wan, Xiang; Zhu, Liqiang; Shi, Yi; Wan, Qing

    2016-01-01

    Recent progress in using biomaterials to fabricate functional electronics has got growing attention for the new generation of environmentally friendly and biocompatible electronic devices. As a kind of biological material with rich source, proteins are essential natural component of all organisms. At the same time, artificial synaptic devices are of great significance for neuromorphic systems because they can emulate the signal process and memory behaviors of biological synapses. In this report, natural chicken albumen with high proton conductivity was used as the coupling electrolyte film for organic/inorganic hybrid synaptic devices fabrication. Some important synaptic functions including paired-pulse facilitation, dynamic filtering, short-term to long-term memory transition and spatial summation and shunting inhibition were successfully mimicked. Our results are very interesting for biological friendly artificial neuron networks and neuromorphic systems. PMID:27008981

  2. Artificial Synaptic Devices Based on Natural Chicken Albumen Coupled Electric-Double-Layer Transistors

    NASA Astrophysics Data System (ADS)

    Wu, Guodong; Feng, Ping; Wan, Xiang; Zhu, Liqiang; Shi, Yi; Wan, Qing

    2016-03-01

    Recent progress in using biomaterials to fabricate functional electronics has got growing attention for the new generation of environmentally friendly and biocompatible electronic devices. As a kind of biological material with rich source, proteins are essential natural component of all organisms. At the same time, artificial synaptic devices are of great significance for neuromorphic systems because they can emulate the signal process and memory behaviors of biological synapses. In this report, natural chicken albumen with high proton conductivity was used as the coupling electrolyte film for organic/inorganic hybrid synaptic devices fabrication. Some important synaptic functions including paired-pulse facilitation, dynamic filtering, short-term to long-term memory transition and spatial summation and shunting inhibition were successfully mimicked. Our results are very interesting for biological friendly artificial neuron networks and neuromorphic systems.

  3. New Artificial Urinary Sphincter Devices in the Treatment of Male Iatrogenic Incontinence

    PubMed Central

    Vakalopoulos, Ioannis; Kampantais, Spyridon; Laskaridis, Leonidas; Chachopoulos, Vasileios; Koptsis, Michail; Toutziaris, Chrysovalantis

    2012-01-01

    Severe persistent stress incontinence following radical prostatectomy for prostate cancer treatment, although not very common, remains the most annoying complication affecting patient's quality of life, despite good surgical oncological results. When severe incontinence persists after the first postoperative year and conservative treatment has been failed, surgical treatment has to be considered. In these cases it is generally accepted that artificial urinary sphincter is the gold standard treatment. AUS 800 by American Medical Systems has been successfully used for more than 35 years. Recently three more sphincter devices, the Flow-Secure, the Periurethral Constrictor, and the ZSI 375, have been developed and presented in the market. A novel type of artificial urinary sphincter, the Tape Mechanical Occlusive Device, has been inserted in live canines as well as in human cadavers. These new sphincter devices are discussed in this paper focusing on safety and clinical results. PMID:22567002

  4. Cycle testing of the MagScrew total artificial heart external battery pack.

    PubMed

    Casas, Fernando; Weber, Stephan; Klatte, Ryan; Luangphakdy, Viviane; Smith, William A

    2007-09-01

    MagScrew total artificial heart (TAH) external battery pack (EBP) cycle bench testing was conducted on two Wilson Greatbatch (Clarence, NY, USA) lithium ion EBPs over a period of 22 months during continuous charge and discharge cycles under a simulated TAH system current requirement. A custom electronic load was developed to simulate the MagScrew current waveforms typically observed during nominal operation. These current load profiles were applied to the EBP under test during a voltage-defined discharge cycle. EBP endurance indicated a 240-min discharge cycle on a new battery diminishing linearly to 175 min after 800 cycles. A second linear trend started at this knee with 150 min of discharge time at 850 cycles until 10 min at 1600 cycles. Even at 1300 cycles, the EBP could still provide enough power for 60 min of nominal operation. In conclusion, the endurance performance of this EBP was satisfactory while exhibiting a predictable wear-out trend.

  5. Implantation of a newly developed direct optic nerve electrode device for artificial vision in rabbits.

    PubMed

    Sakaguchi, Hirokazu; Kamei, Motohiro; Nishida, Kentaro; Terasawa, Yasuo; Fujikado, Takashi; Ozawa, Motoki; Nishida, Kohji

    2012-09-01

    The purpose of this study was to investigate the surgical procedures involved in the implantation of a newly developed direct optic nerve electrode device for inducing artificial vision. The electrode device comprised seven wire stimulation electrodes and a return electrode (diameter 50 μm), one manipulation rod (diameter 100 μm), and a cylindrical silicone board (diameter 2.0 mm). The stimulation electrodes and the manipulation rod protruded through the board to allow implantation of the electrode tips into the optic disc of the rabbit eye. The surgical procedures required to insert the device into the vitreous cavity and implant the device into the optic disc were evaluated. When the electrodes were stimulated, electrically evoked potentials (EEPs) were recorded at the visual cortex. The electrode device was inserted into the vitreous cavity with no damage using a trocar through a scleral incision. The device was easily manipulated using vitreoretinal forceps in the vitreous cavity, and the electrode tips were implanted into the optic disc in a single insertion after vitrectomy. When electrical stimulation was applied, EEPs were recorded from all electrode pairs. The newly developed electrode device was inserted into the eye and implanted into the optic nerve disc smoothly and safely, suggesting that these surgical procedures are useful for our artificial vision system.

  6. Assessment of heart rate variability based on mobile device for planning physical activity

    NASA Astrophysics Data System (ADS)

    Svirin, I. S.; Epishina, E. V.; Voronin, V. V.; Semenishchev, E. A.; Solodova, E. N.; Nabilskaya, N. V.

    2015-05-01

    In this paper we present a method for the functional analysis of human heart based on electrocardiography (ECG) signals. The approach using the apparatus of analytical and differential geometry and correlation and regression analysis. ECG contains information on the current condition of the cardiovascular system as well as on the pathological changes in the heart. Mathematical processing of the heart rate variability allows to obtain a great set of mathematical and statistical characteristics. These characteristics of the heart rate are used when solving research problems to study physiological changes that determine functional changes of an individual. The proposed method implemented for up-to-date mobile Android and iOS based devices.

  7. Heparin coating durability on artificial heart valves studied by XPS and antithrombin binding capacity.

    PubMed

    Kristensen, E M E; Larsson, R; Sánchez, J; Rensmo, H; Gelius, U; Siegbahn, H

    2006-04-15

    The durability and functionality of a heparin coating on artificial heart valve leaflets were evaluated with X-ray photoelectron spectroscopy (XPS) and by the coatings' capacity to bind antithrombin. Current methods for accelerated life-time testing are based on exposing leaflets to water solutions. In this paper a method is explored, in which heart valve leaflets were exposed to a continuous high shear rate (4 L/min) of human citrated plasma. It was found that the heparin coating was stable and wear resistant enough to still be present after 3 weeks and to have about the same antithrombin uptake as coatings not exposed to circulating plasma. It was, however, partly destroyed by the test as found using XPS. We suggest that heparin chains from the upper layer of heparin have been torn off from the carrier chain, in combination with loss of heparin conjugate and plasma deposition in patches. This study showed that XPS provides additional information to biological measurements such as antithrombin uptake. XPS is therefore a valuable technique not only to characterize biomaterials but also to evaluate the effect of a performance test.

  8. The MAVID heart holder: a demonstration device to anchor cadaver hearts for surgical simulation and practical education.

    PubMed

    Mavroudis, Constantine; Idriss, Rachid; Klaus, Kristen E

    2015-12-01

    Performing open heart surgery involves learning challenging techniques and a need for realistic training models to achieve and maintain a high level of surgical skills. The MAVID heart holder is an organ holder primarily designed to hold the heart in its anatomic position for the purpose of surgical simulation and education, thereby closing the gap between surgical performance in the laboratory and in the operating room. The device is simple to use, can be adjusted to organ size, and has the necessary instrumentation to be used with any solid organ. The MAVID heart holder also provides a platform for presentation and assists in advancing the research sphere. The advantage over other existing models is that the MAVID heart holder uses real tissue and does not distort the organ at the attachment sites. Further, it offers superior stability as well as the ability to manipulate the organ during presentation and dissection. Training with the MAVID heart holder has the potential to shorten training time to acquire surgical skills and proficiency before performing these techniques in the operating room and in so doing enhance patient safety.

  9. Application of an unstructured grid algorithm to artificial heart valve simulations.

    PubMed

    Hsu, A T; Yun, J X; Hwang, N H

    1999-01-01

    The time varying flow pattern in the vicinity of mechanical heart valves (MHV) is fairly complex: it involves multiple passages and moving leaflets. The numeric simulation of unsteady flows in these multiple passages with moving boundaries presents a major challenge to computational fluid dynamics (CFD). Two major difficulties in the numeric simulation of MHV flows are 1) the generation of a body fitted grid within the multipassage device and 2) moving leaflets. The conventional finite difference and finite volume scheme obtained by using a structured grid have serious deficiencies in these applications. To fit the grid lines with the various angles of the moving MHV, the grid may often become too skewed for accurate numeric solution. To overcome these deficiencies, significant effort and attention should be placed on the grid generation and moving grid scheme. We present an unstructured moving grid finite volume method for heart valve simulations. The Navier-Stokes equations are discretized on a general tetrahedral mesh by using a finite volume scheme. With this scheme, the mesh can be automatically generated with any commercial software. The method is applied to a tilting disk (Medtronic Hall 29mm, Medtronic, Inc., Minneapolis, MN) heart valve, and results are compared with that of the steady flow solutions. Significant differences between steady and unsteady flow solutions are observed. PMID:10593690

  10. Current status of third-generation implantable left ventricular assist devices in Japan, Duraheart and HeartWare.

    PubMed

    Sawa, Yoshiki

    2015-06-01

    Recently, left ventricular assist devices (LVADs) have become a viable therapeutic approach as a bridge to cardiac transplantation, as well as destination therapy or as part of the bridge to recovery. In Japan, paracorporeal pneumatic devices are the only choice for such therapy, as implantable LVADs are not yet generally available due to device lag, which represents a serious problem in this field. Clinical trials of four different continuous-flow pumps, both axial and centrifugal flow types, were completed at about the same time, and two of those devices, DuraHeart and EVAHEART, have already been approved for use in Japan. Thus, reports of advanced treatment for severe heart failure with these devices are expected. The DuraHeart (Terumo Heart, Ann Arbor, MI, USA) and another device named the HeartWare (HeartWare Inc, Miami Lakes, FL, USA) are so-called third-generation devices, as they have achieved miniaturization and improvements in performance from the use of magnetic levitation. Based on our experiences from both clinical research and experimental use, we herein discuss the DuraHeart and HeartWare devices, with a focus on the clinical outcomes and management strategies. Because of the long waiting period for heart transplantation in Japan, these two devices are considered to have important roles in the near future for the treatment of severe heart failure, and a comprehensive strategy for LVAD therapy including such third-generation implantable devices is expected. PMID:25139211

  11. Current Approaches to Device Implantation in Pediatric and Congenital Heart Disease Patients

    PubMed Central

    Miller, Jacob R; Lancaster, Timothy S; Eghtesady, Pirooz

    2015-01-01

    Summary The pediatric ventricular assist device (VAD) has recently shown substantial improvements in survival as a bridge to heart transplant for patients with end-stage heart failure. Since that time, its use has become much more frequent. With increasing utilization, additional questions have arisen including patient selection, timing of VAD implantation and device selection. These challenges are amplified by the uniqueness of each patient, the recent abundance of literature surrounding VAD use, as well as the technological advancements in the devices themselves. Ideal strategies for device placement must be sought, for not only improved patient care, but for optimal resource utilization. Here, we review the most relevant literature to highlight some of the challenges facing the heart failure specialist, and any physician, who will care for a child with a VAD. PMID:25732410

  12. First Report of 90-Day Support of Two Calves with a Continuous-Flow Total Artificial Heart

    PubMed Central

    Karimov, Jamshid H.; Moazami, Nader; Kobayashi, Mariko; Sale, Shiva; Such, Kimberly; Byram, Nicole; Sunagawa, Gengo; Horvath, David; Gao, Shengqiang; Kuban, Barry; Golding, Leonard A.; Fukamachi, Kiyotaka

    2015-01-01

    Objective The Cleveland Clinic continuous-flow total artificial heart (CFTAH) is a compact, single-piece, valveless, pulsatile pump providing self-regulated hemodynamic output to left/right circulation. We evaluated chronic in vivo pump performance, physiologic and hemodynamic parameters, and biocompatibility of the CFTAH in a well-established calf model. Methods CFTAH pumps have been implanted in 17 calves total. Hemodynamics, pump performance, and device-related adverse events were evaluated during studies and at necropsy. Results In vivo experiments demonstrated good hemodynamic performance (pump flow, 7.3 ± 0.7 L/min; left atrial pressure [LAP], 16 ± 3 mm Hg; right atrial pressure [RAP], 17 ± 3 mm Hg; RAP-LAP difference, 1 ± 2 mm Hg; mean arterial pressure, 103 ± 7 mm Hg; arterial pulse pressure, 30 ± 11 mm Hg; pulmonary arterial pressure, 34 ± 5 mm Hg). The CFTAH has operated within design specifications and never failed. With ever-improving pump design, the implants have shown no chronic hemolysis. Three recent animals with the CFTAH recovered well, with no postoperative anticoagulation, during planned in vivo durations of 30, 90, and 90 days (last two were intended to be 90-day studies). All these longest-surviving cases showed good biocompatibility, with no thromboembolism in organs. Conclusions The current CFTAH has demonstrated reliable self-regulation of hemodynamic output and acceptable biocompatibility without anticoagulation throughout 90 days of chronic implantation in calves. Meeting these milestones is in accord with our strategy to achieve transfer of this unique technology to surgical practice, thus filling the urgent need for cardiac replacement devices as destination therapy. PMID:26173607

  13. Designing artificial photosynthetic devices using hybrid organic-inorganic modules based on polyoxometalates.

    PubMed

    Symes, Mark D; Cogdell, Richard J; Cronin, Leroy

    2013-08-13

    Artificial photosynthesis aims at capturing solar energy and using it to produce storable fuels. However, while there is reason to be optimistic that such approaches can deliver higher energy conversion efficiencies than natural photosynthetic systems, many serious challenges remain to be addressed. Perhaps chief among these is the issue of device stability. Almost all approaches to artificial photosynthesis employ easily oxidized organic molecules as light harvesters or in catalytic centres, frequently in solution with highly oxidizing species. The 'elephant in the room' in this regard is that oxidation of these organic moieties is likely to occur at least as rapidly as oxidation of water, meaning that current device performance is severely curtailed. Herein, we discuss one possible solution to this problem: using self-assembling organic-polyoxometalate hybrid structures to produce compartments inside which the individual component reactions of photosynthesis can occur without such a high incidence of deleterious side reactions.

  14. Development of a new device for artificial insemination in cynomolgus macaques

    PubMed Central

    KOYAMA, Shuzo; FUKUDA, Koji; WATANABE, Sho; KOHARA, Sakae; TSUCHIYA, Hideaki; FUKUZAKI, Koichiro; NAGANO, Masashi; UNO, Yasuhiro; HOSOI, Yoshihiko

    2016-01-01

    In cynomolgus macaques, an important animal species for biomedical research, efficient reproduction has been hampered partly due to the difficulties of artificial insemination (AI) using straw tubes developed for humans or farm animals, because cynomolgus macaques have a complex cervical canal structure. In this study, taking into consideration the unique structure of the macaque cervical canal, we developed a novel device for AI, comprised of a syringe and an outer cylinder. At 24 and 48 h after using this device to inject semen into one female, viable sperm were observed in the oviduct where the sperm meets the oocytes. We then attempted AI using this new device on 10 females that were at pre-ovulation, and pregnancy was successful in three animals (30% pregnancy rate). These results show that the newly developed device can be used for AI in cynomolgus macaques. PMID:27319580

  15. Design and test of a MEMS strain-sensing device for monitoring artificial knee implants.

    PubMed

    Hasenkamp, W; Thevenaz, N; Villard, J; Bertsch, A; Arami, A; Aminian, K; Terrier, A; Renaud, P

    2013-10-01

    This paper describes the development of a polyimide-based MEMS strain-sensing device. Finite element analysis was used to investigate an artificial knee implant and assist on device design and to optimize sensing characteristics. The sensing element of the device was fabricated using polyimide micromachining with embedded thin-metallic wires and placed into a knee prosthesis. The device was evaluated experimentally in a mechanical knee simulator using static and dynamic axial load conditions similar to those encountered in vivo. Results indicates the sensor is capable of measuring the strain associated to the total axial forces in the range of approximately 4 times body weight with a good sensitivity and accuracy for events happening within 1 s time window.

  16. Capsule endoscopy in patients with cardiac pacemakers, implantable cardioverter defibrillators and left heart assist devices.

    PubMed

    Bandorski, Dirk; Höltgen, Reinhard; Stunder, Dominik; Keuchel, Martin

    2014-01-01

    According to the recommendations of the US Food and Drug Administration and manufacturers, capsule endoscopy should not be used in patients carrying implanted cardiac devices. For this review we considered studies indexed (until 30.06.2013) in Medline [keywords: capsule endoscopy, small bowel endoscopy, cardiac pacemaker, implantable cardioverter defibrillator, interference, left heart assist device], technical information from Given Imaging and one own publication (not listed in Medline). Several in vitro and in vivo studies included patients with implanted cardiac devices who underwent capsule endoscopy. No clinically relevant interference was noticed. Initial reports on interference with a simulating device were not reproduced. Furthermore technical data of PillCam (Given Imaging) demonstrate that the maximum transmission power is below the permitted limits for cardiac devices. Hence, impairment of cardiac pacemaker, defibrillator or left ventricular heart assist device function by capsule endoscopy is not expected. However, wireless telemetry can cause dysfunction of capsule endoscopy recording. Application of capsule endoscopy is feasible and safe in patients with implanted cardiac devices such as pacemakers, cardioverter defibrillators, and left heart assist devices. Development of new technologies warrants future re-evaluation.

  17. Capsule endoscopy in patients with cardiac pacemakers, implantable cardioverter defibrillators and left heart assist devices

    PubMed Central

    Bandorski, Dirk; Höltgen, Reinhard; Stunder, Dominik; Keuchel, Martin

    2014-01-01

    According to the recommendations of the US Food and Drug Administration and manufacturers, capsule endoscopy should not be used in patients carrying implanted cardiac devices. For this review we considered studies indexed (until 30.06.2013) in Medline [keywords: capsule endoscopy, small bowel endoscopy, cardiac pacemaker, implantable cardioverter defibrillator, interference, left heart assist device], technical information from Given Imaging and one own publication (not listed in Medline). Several in vitro and in vivo studies included patients with implanted cardiac devices who underwent capsule endoscopy. No clinically relevant interference was noticed. Initial reports on interference with a simulating device were not reproduced. Furthermore technical data of PillCam (Given Imaging) demonstrate that the maximum transmission power is below the permitted limits for cardiac devices. Hence, impairment of cardiac pacemaker, defibrillator or left ventricular heart assist device function by capsule endoscopy is not expected. However, wireless telemetry can cause dysfunction of capsule endoscopy recording. Application of capsule endoscopy is feasible and safe in patients with implanted cardiac devices such as pacemakers, cardioverter defibrillators, and left heart assist devices. Development of new technologies warrants future re-evaluation. PMID:24714370

  18. Acquisition of Visual Perception in Blind Adults Using the BrainPort Artificial Vision Device

    PubMed Central

    Pintar, Christine; Arnoldussen, Aimee; Fisher, Christopher

    2015-01-01

    OBJECTIVE. We sought to determine whether intensive low vision rehabilitation would confer any functional improvement in a sample of blind adults using the BrainPort artificial vision device. METHOD. Eighteen adults ages 28–69 yr (n = 10 men and n = 8 women) who had light perception only or worse vision bilaterally spent up to 6 hr per day for 1 wk undergoing structured rehabilitation interventions. The functional outcomes of object identification and word recognition were tested at baseline and after rehabilitation training. RESULTS. At baseline, participants were unable to complete the two functional assessments. After participation in the 1-wk training protocol, participants were able to use the BrainPort device to complete the two tasks with moderate success. CONCLUSION. Without training, participants were not able to perform above chance level using the BrainPort device. As artificial vision technologies become available, occupational therapy practitioners can play a key role in clients’ success or failure in using these devices. PMID:25553750

  19. Exchange of DuraHeart left ventricular assist device via a subcostal approach.

    PubMed

    Kawamura, Masashi; Sakaguchi, Taichi; Miyagawa, Shigeru; Nishi, Hiroyuki; Yoshikawa, Yasushi; Fukushima, Satsuki; Saito, Shunsuke; Ueno, Takayoshi; Kuratani, Toru; Sawa, Yoshiki

    2012-03-01

    We report a successful case of a DuraHeart left ventricular assist device (LVAD) exchange via a subcostal approach. A 35-year-old woman was implanted with a DuraHeart LVAD due to dilated cardiomyopathy. Approximately 8 months after the implantation, the magnetic levitation system failed. The DuraHeart LVAD was exchanged emergently. The pump was freely dissected via a subcostal approach, avoiding redo sternotomy. De-airing of the new pump and the left ventricle was carefully performed. When the systemic flow was transferred from the cardiopulmonary bypass to the DuraHeart LVAD, an adequate flow was not initally obtained. Positional correction of the inflow conduit was needed to obtain full systemic flow. The postoperative course was uneventful. She was successfully discharged and is waiting at home for a heart donation. PMID:21922278

  20. Targeting the autonomic nervous system: measuring autonomic function and novel devices for heart failure management.

    PubMed

    Patel, Hitesh C; Rosen, Stuart D; Lindsay, Alistair; Hayward, Carl; Lyon, Alexander R; di Mario, Carlo

    2013-12-10

    Neurohumoral activation, in which enhanced activity of the autonomic nervous system (ANS) is a key component, plays a pivotal role in heart failure. The neurohumoral system affects several organs and currently our knowledge of the molecular and systemic pathways involved in the neurohumoral activation is incomplete. All the methods of assessing the degree of activation of the autonomic system have limitations and they are not interchangeable. The methods considered include noradrenaline spillover, microneurography, radiotracer imaging and analysis of heart rate and blood pressure (heart rate variability, baroreceptor sensitivity, heart rate turbulence). Despite the difficulties, medications that affect the ANS have been shown to improve mortality in heart failure and the mechanism is related to attenuation of the sympathetic nervous system (SNS) and stimulation of the parasympathetic nervous system. However, limitations of compliance with medication, side effects and inadequate SNS attenuation are issues of concern with the pharmacological approach. The newer device based therapies for sympathetic modulation are showing encouraging results. As they directly influence the autonomic nervous system, more mechanistic information can be gleaned if appropriate investigations are performed at the time of the outcome trials. However, clinicians should be reminded that the ANS is an evolutionary survival mechanism and therefore there is a need to proceed with caution when trying to completely attenuate its effects. So our enthusiasm for the application of these devices in heart failure should be controlled, especially as none of the devices have trial data powered to assess effects on mortality or cardiovascular events.

  1. Update on Renal Replacement Therapy: Implantable Artificial Devices and Bioengineered Organs.

    PubMed

    Attanasio, Chiara; Latancia, Marcela T; Otterbein, Leo E; Netti, Paolo A

    2016-08-01

    Recent advances in the fields of artificial organs and regenerative medicine are now joining forces in the areas of organ transplantation and bioengineering to solve continued challenges for patients with end-stage renal disease. The waiting lists for those needing a transplant continue to exceed demand. Dialysis, while effective, brings different challenges, including quality of life and susceptibility to infection. Unfortunately, the majority of research outputs are far from delivering satisfactory solutions. Current efforts are focused on providing a self-standing device able to recapitulate kidney function. In this review, we focus on two remarkable innovations that may offer significant clinical impact in the field of renal replacement therapy: the implantable artificial renal assist device (RAD) and the transplantable bioengineered kidney. The artificial RAD strategy utilizes micromachining techniques to fabricate a biohybrid system able to mimic renal morphology and function. The current trend in kidney bioengineering exploits the structure of the native organ to produce a kidney that is ready to be transplanted. Although these two systems stem from different technological approaches, they are both designed to be implantable, long lasting, and free standing to allow patients with kidney failure to be autonomous. However, for both of them, there are relevant issues that must be addressed before translation into clinical use and these are discussed in this review.

  2. Update on Renal Replacement Therapy: Implantable Artificial Devices and Bioengineered Organs.

    PubMed

    Attanasio, Chiara; Latancia, Marcela T; Otterbein, Leo E; Netti, Paolo A

    2016-08-01

    Recent advances in the fields of artificial organs and regenerative medicine are now joining forces in the areas of organ transplantation and bioengineering to solve continued challenges for patients with end-stage renal disease. The waiting lists for those needing a transplant continue to exceed demand. Dialysis, while effective, brings different challenges, including quality of life and susceptibility to infection. Unfortunately, the majority of research outputs are far from delivering satisfactory solutions. Current efforts are focused on providing a self-standing device able to recapitulate kidney function. In this review, we focus on two remarkable innovations that may offer significant clinical impact in the field of renal replacement therapy: the implantable artificial renal assist device (RAD) and the transplantable bioengineered kidney. The artificial RAD strategy utilizes micromachining techniques to fabricate a biohybrid system able to mimic renal morphology and function. The current trend in kidney bioengineering exploits the structure of the native organ to produce a kidney that is ready to be transplanted. Although these two systems stem from different technological approaches, they are both designed to be implantable, long lasting, and free standing to allow patients with kidney failure to be autonomous. However, for both of them, there are relevant issues that must be addressed before translation into clinical use and these are discussed in this review. PMID:26905099

  3. A new pulsatile total artificial heart using a single centrifugal pump.

    PubMed

    Imachi, K; Chinzei, T; Abe, Y; Mabuchi, K; Imanishi, K; Yonezawa, T; Kouno, A; Ono, T; Atsumi, K; Isoyama, T

    1991-01-01

    A new pulsatile total artificial heart (TAH) system, combining a single centrifugal pump (CFP) with two three-way valves, was developed. One port of each three-way valve was connected to the inlet and outlet of a CFP, respectively. The other two ports of each valve ware connected to the right and left atrium, pulmonary artery, and aorta. The CFP can perfuse the pulmonary and systemic circulation alternately with pulsatile flow. A prototype system composed of a Sarns' CFP and solenoid valves was connected to a mock circulatory system resulting in 1) a pulsatile TAH that could be produced with a single CFP, 2) 5 L/min of pulsatile output with a normal flow wave form that can be obtained alternately on the right and left side by switching the solenoid valves, and 3) flow balance between the left and the right that could be controlled easily by the length of switching duration. This new system could be miniaturized and is feasible for a totally implantable TAH.

  4. Selection of a rechargeable internal back-up battery for a totally implantable artificial heart.

    PubMed

    Honda, H; Shiba, K; Shu, E; Koshiji, K; Murai, T; Nakamura, T; Masuzawa, T; Tatsumi, E; Taenaka, Y; Takano, H

    1999-01-01

    Three kinds of rechargeable batteries, NiCd, NiMH, and Li+, were compared for the purpose of selecting the most appropriate battery for use in a Rechargeable Internal Back-up Battery (RIBB) unit for a Totally Implantable Artificial Heart. Batteries of each kind were connected in series to obtain the required driving voltage of 24 V. The NiCd and NiMH batteries were charged by a constant current of 1 C, and the Li+ batteries were charged first by a constant current of 1 C and later by a constant voltage of 28.7 V. All three types of batteries were discharged using a dummy electronic pulsatile load consuming 20 W of power. The tests showed that the Li+ batteries were capable of supplying the required energy for more than 60 minutes. The Li+ batteries had a specific energy of 121.5 Wh/kg, which was more than 3x that of the NiCd and NiMH, and an energy density of 282.5 Wh/L more than double that of the other two. In addition, the Li+ batteries recorded the least temperature rise during charging and discharging. The results of our tests conclusively showed that the Li+ battery is the best among the three for use in an RIBB from the viewpoint of energy density and temperature rise.

  5. Cycle testing of the MagScrew total artificial heart external battery pack: update I.

    PubMed

    Casas, Fernando; Weber, Stephan; Klatte, Ryan; Goel, Vikash; Smith, William A

    2011-02-01

    MagScrew total artificial heart (TAH) external battery pack (EBP) cycle bench testing continued over a period of 18 months using two fresh Wilson Greatbatch lithium ion EBPs during continuous charge and discharge cycles under a simulated TAH system current requirement. The same electronic load developed for our initial testing was used to simulate the MagScrew current waveforms typically observed during nominal operation. The current load profiles for this test were modified from the ones previously described and applied to the EBP under test during a voltage-defined discharge cycle. The test ended when EBP#2 reached end of life at 1450 cycles. At that point, EBP#1 remained healthy with a capacity of 175 min until full discharge. Performance of EBP#2 was still within expected ranges. Performance of EBP#1 exceeded expectations. These differences are probably caused by slight manufacturing changes. More tests will provide additional data to define a statistical distribution to better characterize EBP performance. In conclusion, endurance performance of the EBP remained satisfactory.

  6. Progress of an electrohydraulic total artificial heart system with a separate energy converter.

    PubMed

    Masuzawa, T; Tatsumi, E; Taenaka, Y; Nakamura, M; Endo, S; Takano, H; Koshiji, K; Fukui, Y; Murai, T; Tsukahara, K

    1999-01-01

    We have been developing an electrohydraulic total artificial heart (EHTAH) system. The system consists of diaphragm blood pumps, an abdominally placed energy converter, an internal controller, a transcutaneous energy transfer (TET) system, a transcutaneous optical information transfer system, and internal and external lithium-ion (Li-ion) batteries. The energy converter was optimized to obtain better oil transfer. Maximum cardiac output and efficiency of the EHTAH were increased from 8 L/min to 10 L/min and from 10% to 12%, respectively. The volume of the energy converter was reduced from 280 to 210 ml. The pumping unit was successfully implanted in 68-85 kg calves without anatomic problems, and the calves survived up to 10 days with good circulatory results. The maximum temperature rise of the implanted energy converter was only 1 degrees C. Stable performance of the TET system was confirmed in goats for more than 1 month. DC-DC energy transfer efficiency with 20 W of energy transmission remained within the range of 80% to 85%, and no significant temperature rise was observed in the implanted circuit. The internal Li-ion battery was also evaluated in a goat, and the maximum temperature rise during the charging period was 1.5 degrees C, while the charging and discharging times were 72 and 58 min, respectively. We conclude that our system has progressed in its development as a practical implantable system.

  7. Mixed venous oxygen saturation as a promising parameter for physiologic control of total artificial heart.

    PubMed

    Nakamura, M; Homma, A; Tatsumi, E; Uesho, K; Taenaka, Y; Masuzawa, T; Nakamura, T; Zhang, B; Kakuta, Y; Imada, K; Nakatani, T; Takano, H

    2000-01-01

    Mixed venous oxygen saturation (SvO2) has been proposed as one of the suitable parameters for physiologic control of a total artificial heart (TAH). To establish the practical application of SvO2, we investigated the response of cardiac output (CO) and SvO2 to step-loaded exercise. A normal calf was surgically equipped with an ultrasonic flowmeter probe and an oximetry catheter in the pulmonary artery to measure CO and SvO2, respectively. Three stage step treadmill exercise tests (1, 2, and 4 km/h) were performed three times. While CO increased from 8.9 L/min at preexercise level to 9.7, 10.2 and 11.4 L/min at 1, 2, and 4 km/h, respectively, SvO2 decreased from 59.6% to 56.8, 55.3, and 52.2%, respectively. There existed a linear correlation between the magnitude of changes in CO and SvO2. CO and SvO2 exhibited a similar course of change, expressing an inverted exponential curve. The time constant of SvO2 was from 19 to 35 seconds, whereas that of CO was from 21 to 39 seconds. We conclude that SvO2 changes in close association with CO during exercise and has good potential to be a parameter for physiologic control of a TAH, by reflecting the recipient's CO demand without conspicuous time delay.

  8. Emergent Interhospital Transport of Pediatric Patient With a Berlin Heart Device.

    PubMed

    Hertzog, James H; Pearson, Thomas E; Priest, Marc A; Spurrier, Ellen; Davies, Ryan R

    2016-01-01

    Ventricular assist devices (VADs) for the mechanical support of cardiac failure are being used more frequently in children of increasingly younger age. These children have significant and multiple medical comorbidities, and their length of hospital stay has been increasing. As this population of hospitalized VAD-supported children increases, so does the possibility of their need for interfacility transport for specialized diagnostic or therapeutic procedures. Reports on such transports are limited to 3 children who underwent scheduled elective transfers. We report our experience with a child with a Berlin Heart EXCOR left ventricular assist device (Berlin Heart, Berlin, Germany) who required emergent interfacility transport between our hospital and an affiliated institution. PMID:27637444

  9. Low power laser protects human erythrocytes In an In vitro model of artificial heart-lung machines.

    PubMed

    Itoh, T; Murakami, H; Orihashi, K; Sueda, T; Kusumoto, Y; Kakehashi, M; Matsuura, Y

    2000-11-01

    The protective effect of the low power helium-neon (He-Ne) laser against the damage of human erythrocytes in whole blood was examined in a perfusion model using an artificial heart-lung machine. Preserved human whole blood was diluted and perfused in 2 closed circuits with a double roller pump. The laser irradiated one of the circuits (laser group), and none the other (control group). In the laser group, erythrocyte deformability and erythrocyte adenosine triphosphate (ATP) levels were significantly higher, and free hemoglobin levels were significantly lower than those in the control group. Subsequent morphological findings by means of scanning electron microscope were consistent with these results. Low power He-Ne laser protected human erythrocytes in the preserved diluted whole blood from the damage caused by experimental artificial heart-lung machines. The clinical application of low power laser treatment for extracorporeal circulation is suggested.

  10. Numerical Model of Full Cardiac Cycle Hemodynamics in a Total Artificial Heart and the Effect of Its Size on Platelet Activation

    PubMed Central

    Marom, Gil; Chiu, Wei-Che; Crosby, Jessica R.; DeCook, Katrina J.; Prabhakar, Saurabh; Horner, Marc; Slepian, Marvin J.; Bluestein, Danny

    2014-01-01

    The SynCardia total artificial heart (TAH) is the only FDA approved device for replacing hearts in patients with congestive heart failure. It pumps blood via pneumatically driven diaphragms and controls the flow with mechanical valves. While it has been successfully implanted in more than 1,300 patients, its size precludes implantation in smaller patients. This study’s aim was to evaluate the viability of scaled-down TAHs by quantifying thrombogenic potentials from flow patterns. Simulations of systole were first conducted with stationary valves, followed by an advanced full-cardiac-cycle model with moving valves. All the models included deforming diaphragms and platelet suspension in the blood flow. Flow stress-accumulations were computed for the platelet trajectories and thrombogenic potentials were assessed. The simulations successfully captured complex flow patterns during various phases of the cardiac-cycle. Increased stress-accumulations, but within the safety margin of acceptable thrombogenicity, were found in smaller TAHs, indicating that they are clinically viable. PMID:25354999

  11. Improvement in magnetic field immunity of externally-coupled transcutaneous energy transmission system for a totally implantable artificial heart.

    PubMed

    Yamamoto, Takahiko; Koshiji, Kohji; Homma, Akihiko; Tatsumi, Eisuke; Taenaka, Yoshiyuki

    2008-01-01

    Transcutaneous energy transmission (TET) that uses electromagnetic induction between the external and internal coils of a transformer is the most promising method to supply driving energy to a totally implantable artificial heart without invasion. Induction-heating (IH) cookers generate magnetic flux, and if a cooker is operated near a transcutaneous transformer, the magnetic flux generated will link with the external and internal coils of the transcutaneous transformer. This will affect the performance of the TET and the artificial heart system. Hence, it is necessary to improve the magnetic field immunity of the TET system. During operation of the system, if the transcutaneous transformer is in close proximity to an IH cooker, the electric power generated by the cooker and coupled to the transformer can drive the artificial heart system. To prevent this coupling, the external coil was shielded with a conductive shield that had a slit in it. This reduces the coupling between the transformer and the magnetic field generated by the induction cooker. However, the temperature of the shield increased due to heating by eddy currents. The temperature of the shield can be reduced by separating the IH cooker and the shield.

  12. Spin wave absorber generated by artificial surface anisotropy for spin wave device network

    NASA Astrophysics Data System (ADS)

    Kanazawa, Naoki; Goto, Taichi; Sekiguchi, Koji; Granovsky, Alexander B.; Takagi, Hiroyuki; Nakamura, Yuichi; Inoue, Mitsuteru

    2016-09-01

    Spin waves (SWs) have the potential to reduce the electric energy loss in signal processing networks. The SWs called magnetostatic forward volume waves (MSFVWs) are advantageous for networking due to their isotropic dispersion in the plane of a device. To control the MSFVW flow in a processing network based on yttrium iron garnet, we developed a SW absorber using artificial structures. The mechanical surface polishing method presented in this work can well control extrinsic damping without changing the SW dispersion of the host material. Furthermore, enhancement of the ferromagnetic resonance linewidth over 3 Oe was demonstrated.

  13. [Left ventricular assistant devices for end-stage heart failure: report of two cases].

    PubMed

    Pedemonte, Oneglio; Vera, Andrés; Schmitto, Jan D; Rojas, Sebastián V; Haverich, Axel; Merello, Lorenzo; Novajas, Manuel; Aranda, Fernando; Ibarra, Julio; Muñoz, José A; Alburquerque, Javier; Díaz, Rienzi; Aranguiz-Santander, Ernesto

    2014-07-01

    In the last 2 decades, there have been significant advances in medical treatment of heart failure. However, there is a group of patients who are refractory to the available medical therapy and progress inevitably to a state of end-stage heart failure, whose only therapeutic alternative is cardiac transplantation. But this is an option limited by the scarce availability of donors. Therefore many patients die waiting for an organ. Recently, extra or intracorporeal left ventricular devices have emerged as a viable alternative for patients with end-stage heart failure waiting for a heart transplant. These devices discharge the left ventricle, increasing cardiac output and improving systemic perfusion. This year, in our hospital we began a left ventricular device implantation program for the most severely ill patients on the waiting list for cardiac transplantation. We report two males aged 30 and 53 years, in whom a left ventricular device was successfully implanted, using a minimally invasive surgical technique developed at the University of Hannover in Germany.

  14. A transcutaneous energy transmission system for artificial heart adapting to changing impedance.

    PubMed

    Fu, Yang; Hu, Liang; Ruan, Xiaodong; Fu, Xin

    2015-04-01

    This article presents a coil-coupling-based transcutaneous energy transmission system (TETS) for wirelessly powering an implanted artificial heart. Keeping high efficiency is especially important for TETS, which is usually difficult due to transmission impedance changes in practice, which are commonly caused by power requirement variation for different body movements and coil-couple malposition accompanying skin peristalsis. The TETS introduced in this article is designed based on a class-E power amplifier (E-PA), of which efficiency is over 95% when its load is kept in a certain range. A resonance matching and impedance compressing functions coupled network based on parallel-series capacitors is proposed in the design, to enhance the energy transmission efficiency and capacity of the coil-couple through resonating, and meanwhile compress the changing range of the transmission impedance to meet the load requirements of the E-PA and thus keep the high efficiency of TETS. An analytical model of the designed TETS is built to analyze the effect of the network and also provide bases for following parameters determination. Then, according algorithms are provided to determine the optimal parameters required in the TETS for good performance both in resonance matching and impedance compressing. The design is tested by a series of experiments, which validate that the TETS can transmit a wide range of power with a total efficiency of at least 70% and commonly beyond 80%, even when the coil-couple is seriously malpositioned. The design methodology proposed in this article can be applied to any existing TETS based on E-PA to improve their performance in actual applications.

  15. A transcutaneous energy transmission system for artificial heart adapting to changing impedance.

    PubMed

    Fu, Yang; Hu, Liang; Ruan, Xiaodong; Fu, Xin

    2015-04-01

    This article presents a coil-coupling-based transcutaneous energy transmission system (TETS) for wirelessly powering an implanted artificial heart. Keeping high efficiency is especially important for TETS, which is usually difficult due to transmission impedance changes in practice, which are commonly caused by power requirement variation for different body movements and coil-couple malposition accompanying skin peristalsis. The TETS introduced in this article is designed based on a class-E power amplifier (E-PA), of which efficiency is over 95% when its load is kept in a certain range. A resonance matching and impedance compressing functions coupled network based on parallel-series capacitors is proposed in the design, to enhance the energy transmission efficiency and capacity of the coil-couple through resonating, and meanwhile compress the changing range of the transmission impedance to meet the load requirements of the E-PA and thus keep the high efficiency of TETS. An analytical model of the designed TETS is built to analyze the effect of the network and also provide bases for following parameters determination. Then, according algorithms are provided to determine the optimal parameters required in the TETS for good performance both in resonance matching and impedance compressing. The design is tested by a series of experiments, which validate that the TETS can transmit a wide range of power with a total efficiency of at least 70% and commonly beyond 80%, even when the coil-couple is seriously malpositioned. The design methodology proposed in this article can be applied to any existing TETS based on E-PA to improve their performance in actual applications. PMID:25349072

  16. Development of data communication system with ultra high frequency radio wave for implantable artificial hearts.

    PubMed

    Tsujimura, Shinichi; Yamagishi, Hiroto; Sankai, Yoshiyuki

    2009-01-01

    In order to minimize infection risks of patients with artificial hearts, wireless data transmission methods with electromagnetic induction or light have been developed. However, these methods tend to become difficult to transmit data if the external data transmission unit moves from its proper position. To resolve this serious problem, the purpose of this study is to develop a prototype wireless data communication system with ultra high frequency radio wave and confirm its performance. Due to its high-speed communication rate, low power consumption, high tolerance to electromagnetic disturbances, and secure wireless communication, we adopted Bluetooth radio wave technology for our system. The system consists of an internal data transmission unit and an external data transmission unit (53 by 64 by 16 mm, each), and each has a Bluetooth module (radio field intensity: 4 dBm, receiver sensitivity: -80 dBm). The internal unit also has a micro controller with an 8-channel 10-bit A/D converter, and the external unit also has a RS-232C converter. We experimented with the internal unit implanted into pig meat, and carried out data transmission tests to evaluate the performance of this system in tissue thickness of up to 3 mm. As a result, data transfer speeds of about 20 kbps were achieved within the communication distance of 10 m. In conclusion, we confirmed that the system can wirelessly transmit the data from the inside of the body to the outside, and it promises to resolve unstable data transmission due to accidental movements of an external data transmission unit. PMID:19964616

  17. Implantable control, telemetry, and solar energy system in the moving actuator type total artificial heart.

    PubMed

    Ahn, J M; Lee, J H; Choi, S W; Kim, W E; Omn, K S; Park, S K; Kim, W G; Roh, J R; Min, B G

    1998-03-01

    The moving actuator type total artificial heart (TAH) developed in the Seoul National University has numerous design improvements based upon the digital signal processor (DSP). These improvements include the implantability of all electronics, an automatic control algorithm, and extension of the battery run-time in connection with an amorphous silicon solar system (SS). The implantable electronics consist of the motor drive, main processor, intelligent Li ion battery management (LIBM) based upon the DSP, telemetry system, and transcutaneous energy transmission (TET) system. Major changes in the implantable electronics include decreasing the temperature rise by over 21 degrees C on the motor drive, volume reduction (40 x 55 x 33 mm, 7 cell assembly) of the battery pack using a Li ion (3.6 V/cell, 900 mA.h), and improvement of the battery run-time (over 40 min) while providing the cardiac output (CO) of 5 L/min at 100 mm Hg afterload when the external battery for testing is connected with the SS (2.5 W, 192.192, 1 kg) for the external battery recharge or the partial TAH drive. The phase locked loop (PLL) based telemetry system was implemented to improve stability and the error correction DSP algorithm programmed to achieve high accuracy. A field focused light emitting diode (LED) was used to obtain low light scattering along the propagation path, similar to the optical property of the laser and miniature sized, mounted on the pancake type TET coils. The TET operating resonance frequency was self tuned in a range of 360 to 410 kHz to provide enough power even at high afterloads. An automatic cardiac output regulation algorithm was developed based on interventricular pressure analysis and carried out in several animal experiments successfully. All electronics have been evaluated in vitro and in vivo and prepared for implantation of the TAH. Substantial progress has been made in designing a completely implantable TAH at the preclinical stage. PMID:9527287

  18. Artificial placenta--lung assist devices for term and preterm newborns with respiratory failure.

    PubMed

    Rochow, Niels; Chan, Emily C; Wu, Wen-I; Selvaganapathy, Ponnambalam R; Fusch, Gerhard; Berry, Leslie; Brash, John; Chan, Anthony K; Fusch, Christoph

    2013-06-25

    Respiratory insufficiency is a major cause of neonatal mortality and long-term morbidity, especially in very low birth weight infants. Today, non-invasive and mechanical ventilation are commonly accepted procedures to provide respiratory support to newborns, but they can reach their limit of efficacy. To overcome this technological plateau and further reduce mortality rates, the technology of an "artificial placenta", which is a pumpless lung assist device connected to the umbilical vessels, would serve to expand the therapeutic spectrum when mechanical ventilation becomes inadequate to treat neonates with severe respiratory insufficiency.
The first attempts to create such an artificial placenta took place more than 60 years ago. However, there has been a recent renaissance of this concept, including developments of its major components like the oxygenator, vascular access via umbilical vessels, flow control, as well as methods to achieve hemocompatibility in extracorporeal circuits. This paper gives a review of past and current development, animal experiments and human case studies of artificial placenta technology.

  19. Percutaneous implantation of a parachute device for treatment of ischemic heart failure.

    PubMed

    Cilingiroglu, Mehmet; Rollefson, William A; Mego, David

    2013-01-01

    Congestive heart failure (CHF) secondary to ischemic cardiomyopathy is associated with significant morbidity and mortality despite currently available medical therapy. The Parachute(TM) device is a novel left ventricular partitioning device that is delivered percutaneously in the left ventricle (LV) in patients with anteroapical regional wall motion abnormalities, dilated LV and systolic dysfunction after anterior myocardial infarction with favorable clinical and LV hemodynamic improvements post-implantation. Here, we do review the current literature and present a case of the Parachute device implantation.

  20. [Rise of the machines? Left ventricular assist devices for treatment of severe heart failure].

    PubMed

    Ujeyl, A; Krüger, M

    2015-11-01

    The use of left ventricular assist devices (LVAD) as a treatment for severe heart failure has gained momentum in recent years. Even at this stage the number of worldwide LVAD implantations far exceeds the volume of heart transplantations in view of the chronic shortage of donor organs. Third generation continuous flow assist devices have helped to improve survival, quality of life and symptom burden of heart failure patients in comparison to a regimen of optimal medication management. Alongside bridging to transplantation, destination therapy has become an established strategy of LVAD implantation. A careful patient selection process is crucial for a good clinical outcome after device implantation and risk assessment for postoperative right ventricular failure is of particular importance in this context. The rate of hospitalization during LVAD support is still high, despite the step-wise attempts to widen the indications to less severely ill heart failure patients. An effective perioperative and postoperative management will help to lower the incidence of complications (e.g. bleeding, infections, thromboembolic events and right ventricular failure) and to improve the encouraging results of mechanical circulatory support. PMID:26530283

  1. [Rise of the machines? Left ventricular assist devices for treatment of severe heart failure].

    PubMed

    Ujeyl, A; Krüger, M

    2015-11-01

    The use of left ventricular assist devices (LVAD) as a treatment for severe heart failure has gained momentum in recent years. Even at this stage the number of worldwide LVAD implantations far exceeds the volume of heart transplantations in view of the chronic shortage of donor organs. Third generation continuous flow assist devices have helped to improve survival, quality of life and symptom burden of heart failure patients in comparison to a regimen of optimal medication management. Alongside bridging to transplantation, destination therapy has become an established strategy of LVAD implantation. A careful patient selection process is crucial for a good clinical outcome after device implantation and risk assessment for postoperative right ventricular failure is of particular importance in this context. The rate of hospitalization during LVAD support is still high, despite the step-wise attempts to widen the indications to less severely ill heart failure patients. An effective perioperative and postoperative management will help to lower the incidence of complications (e.g. bleeding, infections, thromboembolic events and right ventricular failure) and to improve the encouraging results of mechanical circulatory support.

  2. Digital image correlation of coated and uncoated Religa Heart_Ext ventricular assist device.

    PubMed

    Kopernik, Magdalena; Gawlikowski, Maciej; Milenin, Andrij; Altyntsev, Ievgenii; Kustosz, Roman; Kąc, Sławomir

    2015-01-01

    The digital image correlation is used to estimate influence of deposited heamocompatible coatings (gold and titanium nitride) on mechanical response of ventricular assist device Religa Heart_Ext made of Bionate II (thermoplastic polycarbonate urethane) under working conditions by comparison of the coated Religa Heart_Ext with uncoated Religa Heart_Ext. The DIC is applied for experimental investigation of the strains and displacements distribution on external surface of the blood chamber of ventricular assist device during loading. The experiment was conducted in a hydraulic system with water at operating temperatures of 25 and 37 °C, as well as under static pressures: 80, 120, 180, 220 and 280 mmHg, and static underpressures: -25, -45, -75 mmHg. The subsequent images were taken after stabilization of pressure on a set level. The applied research method shows that the nano-coating of 30 nm in thickness significantly affects deformation of the blood chamber of Religa Heart_Ext in macro scale. The proposed composition of coatings increases strain on external surface of the ventricular assist device. PMID:26899910

  3. Surgical considerations for the explantation of the Parachute left ventricular partitioning device and the implantation of the HeartMate II left ventricular assist device

    PubMed Central

    Bansal, Shelley; Rosas, Paola C.; Mazzaferri, Ernest L.; Sai-Sudhakar, Chittoor B.

    2016-01-01

    Chronic heart failure is the leading cause of death in the world. With newer therapies, the burden of this disease has decreased; however, a significant number of patients remain refractive to existing therapies. Myocardial infarction often leads to ventricular remodeling and eventually contributes to heart failure. The Parachute™ (Cardiokinetix, Menlo Park, CA) is the first device designed for percutaneous ventricular restoration therapy, which reduces left ventricular volume and minimizes the risk of open surgical procedures. For the first time, we report a case of explantation of the Parachute ventricular partitioning device and transition to a HeartMate II™ left ventricular assist device and the surgical considerations for a successful outcome. PMID:27034560

  4. Surgical considerations for the explantation of the Parachute left ventricular partitioning device and the implantation of the HeartMate II left ventricular assist device.

    PubMed

    Ravi, Yazhini; Bansal, Shelley; Rosas, Paola C; Mazzaferri, Ernest L; Sai-Sudhakar, Chittoor B

    2016-04-01

    Chronic heart failure is the leading cause of death in the world. With newer therapies, the burden of this disease has decreased; however, a significant number of patients remain refractive to existing therapies. Myocardial infarction often leads to ventricular remodeling and eventually contributes to heart failure. The Parachute™ (Cardiokinetix, Menlo Park, CA) is the first device designed for percutaneous ventricular restoration therapy, which reduces left ventricular volume and minimizes the risk of open surgical procedures. For the first time, we report a case of explantation of the Parachute ventricular partitioning device and transition to a HeartMate II™ left ventricular assist device and the surgical considerations for a successful outcome. PMID:27034560

  5. Surgical considerations for the explantation of the Parachute left ventricular partitioning device and the implantation of the HeartMate II left ventricular assist device.

    PubMed

    Ravi, Yazhini; Bansal, Shelley; Rosas, Paola C; Mazzaferri, Ernest L; Sai-Sudhakar, Chittoor B

    2016-04-01

    Chronic heart failure is the leading cause of death in the world. With newer therapies, the burden of this disease has decreased; however, a significant number of patients remain refractive to existing therapies. Myocardial infarction often leads to ventricular remodeling and eventually contributes to heart failure. The Parachute™ (Cardiokinetix, Menlo Park, CA) is the first device designed for percutaneous ventricular restoration therapy, which reduces left ventricular volume and minimizes the risk of open surgical procedures. For the first time, we report a case of explantation of the Parachute ventricular partitioning device and transition to a HeartMate II™ left ventricular assist device and the surgical considerations for a successful outcome.

  6. Electromagnetic interference of automatic implantable cardioverter defibrillator and HeartWare left ventricular assist device.

    PubMed

    Labedi, Mohamed R; Alharethi, Rami; Kfoury, A G; Budge, Deborah; Bruce, Reid; Rasmusson, Brad; Bunch, T Jared

    2013-01-01

    The use of continuous-flow left ventricular assist devices (LVAD) have markedly improved outcomes in patients with advanced heart failure (HF). The HeartWare LVAD is a miniaturized centrifugal pump implanted within the pericardial space. Implantable cardioverter-defibrillators (ICDs) are susceptible to oversensing of extracardiac signals (electromagnetic interference [EMI]). We report two cases of EMI in patients that received a HeartWare LVAD as destination therapy for advanced HF. The patients were 75 and 78 years old, both with severe ischemic dilated cardiomyopathy (ejection fraction < 0.20) and New York Heart Association class 4 heart failure. Both patients had a St. Jude Medical Unify ICD with a 7 Fr dual coil St. Jude Medical Durata ICD lead. In both patients, the lead location was in the right ventricular apex with an inferior orientation. Both patients experienced immediate ICD therapies after LVAD placement, requiring the tachytherapies to be disabled. ICD programming changes to increase sensitivity and the detection windows were ineffective. Both patients underwent ICD system revision. In one patient, the existing lead was moved to an anteroseptal location that stopped the EMI. In the other patient, the ICD system was changed to allow a separate right ventricular sensing lead in an anteroseptal location and a dual coil ICD lead placed in an apical location, a strategy used to obtain an acceptable defibrillation threshold. The patients have had no subsequent EMI detected on clinical and remote monitoring. Patients with a right ventricular apical ICD lead placement that undergo placement of a HeartWare LVAD are susceptible to EMI and inappropriate ICD therapies. These cases suggest the primary mechanism is proximity of the ICD lead to the device and as such relocation to an anteroseptal location can overcome the problem. These data suggest that all patients that receive a HeartWare LVAD with an ICD should have the device carefully checked at maximum LVAD

  7. Evolvement of left ventricular assist device: the implications on heart failure management.

    PubMed

    Chair, Sek Ying; Yu, Doris Sf; Ng, Michael Timothy; Wang, Qun; Cheng, Ho Yu; Wong, Eliza Ml; Sit, Janet Wh

    2016-07-01

    Heart failure (HF) is a potentially fatal disease that affects increasing number of people worldwide. Although heart transplant is the "gold standard" therapy for HF, due to the limited availability of organs, many patients died when waiting for the transplant. Left ventricular assist device (LVAD), as a mechanical circulatory support, has become a new light for patients with HF. With the technical advancements, LVADs work not only as a bridge to transplant, but also assist heart recovery and even as a destination therapy in long-term treatment. This observation paper reviewed the development of LVAD and its clinical roles. The challenges and possible solutions in nursing care for patients with LVAD at different stage of implantation were discussed. The healthcare professionals could obtain a better understanding about the LVAD treatment for HF patients. PMID:27594870

  8. Evolvement of left ventricular assist device: the implications on heart failure management

    PubMed Central

    Chair, Sek Ying; Yu, Doris SF; Ng, Michael Timothy; Wang, Qun; Cheng, Ho Yu; Wong, Eliza ML; Sit, Janet WH

    2016-01-01

    Heart failure (HF) is a potentially fatal disease that affects increasing number of people worldwide. Although heart transplant is the “gold standard” therapy for HF, due to the limited availability of organs, many patients died when waiting for the transplant. Left ventricular assist device (LVAD), as a mechanical circulatory support, has become a new light for patients with HF. With the technical advancements, LVADs work not only as a bridge to transplant, but also assist heart recovery and even as a destination therapy in long-term treatment. This observation paper reviewed the development of LVAD and its clinical roles. The challenges and possible solutions in nursing care for patients with LVAD at different stage of implantation were discussed. The healthcare professionals could obtain a better understanding about the LVAD treatment for HF patients.

  9. Evolvement of left ventricular assist device: the implications on heart failure management

    PubMed Central

    Chair, Sek Ying; Yu, Doris SF; Ng, Michael Timothy; Wang, Qun; Cheng, Ho Yu; Wong, Eliza ML; Sit, Janet WH

    2016-01-01

    Heart failure (HF) is a potentially fatal disease that affects increasing number of people worldwide. Although heart transplant is the “gold standard” therapy for HF, due to the limited availability of organs, many patients died when waiting for the transplant. Left ventricular assist device (LVAD), as a mechanical circulatory support, has become a new light for patients with HF. With the technical advancements, LVADs work not only as a bridge to transplant, but also assist heart recovery and even as a destination therapy in long-term treatment. This observation paper reviewed the development of LVAD and its clinical roles. The challenges and possible solutions in nursing care for patients with LVAD at different stage of implantation were discussed. The healthcare professionals could obtain a better understanding about the LVAD treatment for HF patients. PMID:27594870

  10. UV emissions from artificial tanning devices and their compliance with the European technical standard.

    PubMed

    Facta, Stefania; Fusette, Stefania Saudino; Bonino, Alessandro; Anglesio, Laura; d'Amore, Giovanni

    2013-04-01

    Use of ultraviolet radiation-emitting tanning devices has been classified as "carcinogenic to humans" (group 1) by the International Agency for Research on Cancer. Following this classification, the knowledge of typical ultraviolet emission levels from tanning devices can be of interest for evaluating their impact on health. In this work, the results of an extensive measurement campaign on artificial tanning appliances are presented. Ultraviolet emissions from 94 tanning appliances produced by 15 different manufacturers were characterized by onsite spectroradiometric measurements. The measured radiometric quantities were compared with reference values fixed in the European technical standard EN 60335-2-27 "Household and similar electrical appliances-Safety. Part 2: Particular requirements for appliances for skin exposure to ultraviolet and infrared radiation." Measurement results indicate that 88% of the examined appliances had ultraviolet emissions not compliant with the technical standard. Among the considered appliances, tanning devices equipped with low pressure lamps showed higher ultraviolet levels of effective irradiance and less compliance with standard requirements. In particular, UV emissions from 100% of low pressure appliances and from 78% of high pressure appliances exceeded the irradiance limit of 0.3 Wm set by the European technical standard.

  11. UV emissions from artificial tanning devices and their compliance with the European technical standard.

    PubMed

    Facta, Stefania; Fusette, Stefania Saudino; Bonino, Alessandro; Anglesio, Laura; d'Amore, Giovanni

    2013-04-01

    Use of ultraviolet radiation-emitting tanning devices has been classified as "carcinogenic to humans" (group 1) by the International Agency for Research on Cancer. Following this classification, the knowledge of typical ultraviolet emission levels from tanning devices can be of interest for evaluating their impact on health. In this work, the results of an extensive measurement campaign on artificial tanning appliances are presented. Ultraviolet emissions from 94 tanning appliances produced by 15 different manufacturers were characterized by onsite spectroradiometric measurements. The measured radiometric quantities were compared with reference values fixed in the European technical standard EN 60335-2-27 "Household and similar electrical appliances-Safety. Part 2: Particular requirements for appliances for skin exposure to ultraviolet and infrared radiation." Measurement results indicate that 88% of the examined appliances had ultraviolet emissions not compliant with the technical standard. Among the considered appliances, tanning devices equipped with low pressure lamps showed higher ultraviolet levels of effective irradiance and less compliance with standard requirements. In particular, UV emissions from 100% of low pressure appliances and from 78% of high pressure appliances exceeded the irradiance limit of 0.3 Wm set by the European technical standard. PMID:23439142

  12. An innovative artificial fog production device improved in the European project “FOG”

    NASA Astrophysics Data System (ADS)

    Colomb, M.; Hirech, K.; André, P.; Boreux, J. J.; Lacôte, P.; Dufour, J.

    2008-03-01

    Transport safety is a major goal in the European Union. Low visibility conditions, especially due to fog, increase the risk of major accidents (chain collision). Innovative products have been developed by the automotive industry, including equipment manufacturers, to increase the level of safety of car passengers and drivers. Testing of these products requires the simulation or artificial reproduction of low visibility (fog) conditions with good stability and reproducibility characteristics. We report on the results of the European Union funded "FOG" project to improve road transport safety through fog production in an experimental test chamber located at the Clermont-Ferrand laboratory for research on road safety and visibility. The project developed a prototype of a small-scale climatic chamber, an improved fog production spraying device, a laser-based visibility measurement device, a reduced scale transmissometer, and a combined indoor climate-fog production simulation software. The ability of the fog chamber to test for driver reaction was also investigated. Recent developments include a device able to produce stable visibility levels and homogeneous fog, representative of various types of natural water droplet distribution. The fog characteristics were determined and compared to natural fog. Results are presented for a selection of conditions including stabilized visibility levels for dense fog and two kinds of droplet distributions.

  13. Home Discharge and Out-of-Hospital Follow-Up of Total Artificial Heart Patients Supported by a Portable Driver System

    PubMed Central

    2014-01-01

    To enhance ambulation and facilitate hospital discharge of total artificial heart (TAH)–supported patients, we adapted a mobile ventricular assistance device (VAD) driver (Excor) for TAH use and report on the performance of Excor-driven TAH patients discharged home. Ten patients stabilized on a TAH, driven by the CSS (“Circulatory Support System”), were progressively switched over to the Excor in hospital over 14 days as a pilot, with daily hemodynamics and laboratory parameters measured. Twenty-two stable TAH patients were subsequently placed on the Excor, trained, and discharged home. Clinical and hemodynamic parameters were followed. All pilot study patients were clinically stable on the Excor, with no decrease in TAH output noted (6.3 + 0.3 L/min [day 1] vs. 5.8 + 0.2 L/min [day 14], p = 0.174), with a trend suggesting improvement of both hepatic and renal function. Twenty-two TAH patients were subsequently successfully discharged home on the portable driver and were supported out of hospital for up to 598 days (range, 2–598; mean = 179 ± 140 days), remaining ambulatory, New York Heart Association (NYHA) class I or II, and free of readmission for 88.5% of the time of support. TAH patients may be effectively and safely supported by a mobile drive system. As such, the utility of the TAH may be extended to support patients beyond the hospital, at home, with overall ambulatory freedom. PMID:24577369

  14. Use of left ventricular assist device (HeartMate II): a Singapore experience.

    PubMed

    Lim, Choon Pin; Sivathasan, Cumaraswamy; Tan, Teing Ee; Lim, Chong Hee; Kerk, Ka Lee; Sim, David Kheng Leng

    2014-07-01

    Recent advances in medical and device therapies in heart failure have improved the survival of patients with heart failure. However, due to the limited availability of suitable heart donors, left ventricular assist devices (LVADs) have become an important tool as a bridge-to-heart transplantation for patients with refractory heart failure in Singapore. We report our experience with the HeartMate II (HMII) LVAD (Thoratec Corporation, Pleasanton, CA, USA) as a bridge-to-heart transplant in our center from 2009 to 2012. This was a retrospective review of 23 consecutive patients who underwent HMII LVAD implantation in our center between May 2009 and December 2012. All patients were classified as Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) levels 1 to 3 and underwent LVAD implantation as a bridge-to-heart transplant. There were 17 male and 6 female patients. The mean age was 43.6 years old (range 14 to 64). The etiologies of heart failure included ischemic heart disease [8], idiopathic dilated cardiomyopathy [11], viral myocarditis [2], and chemotherapy-induced cardiomyopathy [2]. Nine patients were INTERMACS level 1, 12 patients level 2, and two patients level 3. All patients successfully underwent HMII LVAD implantation. There was no mortality within the first 30 postoperative days. Postoperative complications included stroke with full neurological recovery (21.7%), mediastinal infection (21.7%), cardiac tamponade or mediastinal collection requiring reopening of the chest (39.1%), cardiac arrhythmia (13.0%), and pump thrombosis with pump replacement (4.3%). All patients were discharged from hospital after LVAD implantation. Three patients experienced driveline infections during outpatient follow-up. There were 19 readmissions due to the following conditions: sub-therapeutic anticoagulation (13.0%), gastrointestinal bleeding (13.0%), suspected pump thrombosis (13.0%), transient ischemic attack (8.7%), arrhythmia (8.7%), congestive

  15. Mechanical and Electrical Characterization of Piezoelectric Artificial Cochlear Device and Biocompatible Packaging.

    PubMed

    Jung, Youngdo; Kwak, Jun-Hyuk; Kang, Hanmi; Kim, Wan Doo; Hur, Shin

    2015-07-31

    This paper presents the development of a piezoelectric artificial cochlea (PAC) device capable of analyzing vibratory signal inputs and converting them into electrical signal outputs without an external power source by mimicking the function of human cochlea within an audible frequency range. The PAC consists of an artificial basilar membrane (ABM) part and an implantable packaged part. The packaged part provides a liquid environment through which incoming vibrations are transmitted to the membrane part. The membrane part responds to the transmitted signal, and the local area of the ABM part vibrates differently depending on its local resonant frequency. The membrane was designed to have a logarithmically varying width from 0.97 mm to 8.0 mm along the 28 mm length. By incorporating a micro-actuator in an experimental platform for the package part that mimics the function of a stapes bone in the middle ear, we created a similar experimental environment to cochlea where the human basilar membrane vibrates. The mechanical and electrical responses of fabricated PAC were measured with a laser Doppler vibrometer and a data acquisition system, and were compared with simulation results. Finally, the fabricated PAC in a biocompatible package was developed and its mechanical and electrical characteristics were measured. The experimental results shows successful frequency separation of incoming mechanical signal from micro-actuator into frequency bandwidth within the 0.4 kHz-5 kHz range.

  16. Mechanical and Electrical Characterization of Piezoelectric Artificial Cochlear Device and Biocompatible Packaging

    PubMed Central

    Jung, Youngdo; Kwak, Jun-Hyuk; Kang, Hanmi; Kim, Wan Doo; Hur, Shin

    2015-01-01

    This paper presents the development of a piezoelectric artificial cochlea (PAC) device capable of analyzing vibratory signal inputs and converting them into electrical signal outputs without an external power source by mimicking the function of human cochlea within an audible frequency range. The PAC consists of an artificial basilar membrane (ABM) part and an implantable packaged part. The packaged part provides a liquid environment through which incoming vibrations are transmitted to the membrane part. The membrane part responds to the transmitted signal, and the local area of the ABM part vibrates differently depending on its local resonant frequency. The membrane was designed to have a logarithmically varying width from 0.97 mm to 8.0 mm along the 28 mm length. By incorporating a micro-actuator in an experimental platform for the package part that mimics the function of a stapes bone in the middle ear, we created a similar experimental environment to cochlea where the human basilar membrane vibrates. The mechanical and electrical responses of fabricated PAC were measured with a laser Doppler vibrometer and a data acquisition system, and were compared with simulation results. Finally, the fabricated PAC in a biocompatible package was developed and its mechanical and electrical characteristics were measured. The experimental results shows successful frequency separation of incoming mechanical signal from micro-actuator into frequency bandwidth within the 0.4 kHz–5 kHz range. PMID:26263995

  17. A microfluidic respiratory assist device with high gas permeance for artificial lung applications.

    PubMed

    Kniazeva, Tatiana; Hsiao, James C; Charest, Joseph L; Borenstein, Jeffrey T

    2011-04-01

    One of the principal challenges in artificial lung technology has been the ability to provide levels of oxygen and carbon dioxide exchange that rival those of the natural human lung, while mitigating the deleterious interaction between blood and the surface of the synthetic gas exchange membrane. This interaction is exacerbated by the large oxygenator surface area required to achieve sufficient levels of gas transfer. In an effort to address this challenge, microfluidics-based artificial lung technologies comprising stacked microchannel networks have been explored by several groups. Here we report the design, fabrication and initial testing of a parallel plate multilayered silicone-based microfluidic construct containing ultrathin gas exchange membranes, aimed at maximizing gas transfer efficiency while minimizing membrane-blood contact area. The device comprises a branched microvascular network that provides controlled wall shear stress and uniform blood flow, and is designed to minimize blood damage, thrombosis and inflammatory responses seen in current oxygenators. Initial testing indicates that flow distribution through the multilayer structure is uniform and that the thin membrane can withstand pressures equivalent to those expected during operation. Oxygen transfer using phosphate buffered saline as the carrier fluid has also been assessed, demonstrating a sharp increase in oxygen transfer as membrane thickness is reduced, consistent with the expected values of oxygen permeance for thin silicone membranes.

  18. Exercise Rehabilitation for Chronic Heart Failure Patients with Cardiac Device Implants

    PubMed Central

    Haennel, Robert G.

    2012-01-01

    In the past decade a significant development in the management and rehabilitation of people with chronic heart failure (CHF) has been the utilization of cardiac devices. The use of biventricular pacemakers, referred to as Cardiac Resynchronization Therapy (CRT) can yield improvements in functional abilities for a select group of CHF patients and the inclusion of implantable cardiac defibrillators (ICDs) may reduce the risk of sudden death. This review provides physical therapists with a basic understanding of how to prescribe exercise for people with CHF who have these device implants. PMID:22993499

  19. "And the Beat Goes Ona... Building Artificial Hearts in the Classroom.

    ERIC Educational Resources Information Center

    Brock, David L.

    2000-01-01

    Among the many ideas and theories in anatomy and physiology, one particular topic provides all the potential benefits of learning about the human body: the circulatory system, specifically the heart. Describes a distinctive way to study circulation and the heart that allows students to explore the basic principles of vertebrate anatomy and…

  20. Examination of mitral regurgitation with a goat heart model for the development of intelligent artificial papillary muscle.

    PubMed

    Shiraishi, Y; Yambe, T; Yoshizawa, M; Hashimoto, H; Yamada, A; Miura, H; Hashem, M; Kitano, T; Shiga, T; Homma, D

    2012-01-01

    Annuloplasty for functional mitral or tricuspid regurgitation has been made for surgical restoration of valvular diseases. However, these major techniques may sometimes be ineffective because of chamber dilation and valve tethering. We have been developing a sophisticated intelligent artificial papillary muscle (PM) by using an anisotropic shape memory alloy fiber for an alternative surgical reconstruction of the continuity of the mitral structural apparatus and the left ventricular myocardium. This study exhibited the mitral regurgitation with regard to the reduction in the PM tension quantitatively with an originally developed ventricular simulator using isolated goat hearts for the sophisticated artificial PM. Aortic and mitral valves with left ventricular free wall portions of isolated goat hearts (n=9) were secured on the elastic plastic membrane and statically pressurized, which led to valvular leaflet-papillary muscle positional change and central mitral regurgitation. PMs were connected to the load cell, and the relationship between the tension of regurgitation and PM tension were measured. Then we connected the left ventricular specimen model to our hydraulic ventricular simulator and achieved hemodynamic simulation with the controlled tension of PMs. PMID:23367454

  1. Levosimendan may improve survival in patients requiring mechanical assist devices for post-cardiotomy heart failure

    PubMed Central

    Braun, Jan-Peter; Jasulaitis, Dominik; Moshirzadeh, Maryam; Doepfmer, Ulrich R; Kastrup, Marc; von Heymann, Christian; Dohmen, Pascal M; Konertz, Wolfgang; Spies, Claudia

    2006-01-01

    Introduction Most case series suggest that less than half of the patients receiving a mechanical cardiac assist device as a bridge to recovery due to severe post-cardiotomy heart failure survive to hospital discharge. Levosimendan is the only inotropic substance known to improve medium term survival in patients suffering from severe heart failure. Methods This retrospective analysis covers our single centre experience. Between July 2000 and December 2004, 41 consecutive patients were treated for this complication. Of these, 38 patients are included in this retrospective analysis as 3 patients died in the operating room. Levosimendan was added to the treatment protocol for the last nine patients. Results Of 29 patients treated without levosimendan, 20 could be weaned off the device, 9 survived to intensive care unit discharge, 7 left hospital alive and 3 survived 180 days. All 9 patients treated with levosimendan could be weaned, 8 were discharged alive from ICU and hospital, and 7 lived 180 days after surgery (p < 0.002 for 180 day survival). Plasma lactate after explantation of the device was significantly lower (p = 0.002), as were epinephrine doses. Time spent on renal replacement therapy was significantly shorter (p = 0.023). Conclusion Levosimendan seems to improve medium term survival in patients failing to wean off cardiopulmonary bypass and requiring cardiac assist devices as a bridge to recovery. This retrospective analysis justifies prospective randomised investigations of levosimendan in this group of patients. PMID:16420666

  2. [PULMONARY COMPLICATIONS IN CHILDREN, OPERATED ON FOR INBORN HEART FAILURES IN THE ARTIFICIAL BLOOD CIRCULATION ENVIRONMENT].

    PubMed

    Moshkivska, L V; Nastenko, E A; Golovenko, O S; Lazoryshynets, V V

    2015-11-01

    The risk factors of pulmonary complications occurrence were analyzed in children, operated on for inborn heart failures in atrificial blood circulation environment. Pulmonary complications rate and the risk factors of their occurrence were analyzed.

  3. Incorporating an Exercise Detection, Grading, and Hormone Dosing Algorithm Into the Artificial Pancreas Using Accelerometry and Heart Rate

    PubMed Central

    Jacobs, Peter G.; Resalat, Navid; El Youssef, Joseph; Reddy, Ravi; Branigan, Deborah; Preiser, Nicholas; Condon, John; Castle, Jessica

    2015-01-01

    In this article, we present several important contributions necessary for enabling an artificial endocrine pancreas (AP) system to better respond to exercise events. First, we show how exercise can be automatically detected using body-worn accelerometer and heart rate sensors. During a 22 hour overnight inpatient study, 13 subjects with type 1 diabetes wearing a Zephyr accelerometer and heart rate monitor underwent 45 minutes of mild aerobic treadmill exercise while controlling their glucose levels using sensor-augmented pump therapy. We used the accelerometer and heart rate as inputs into a validated regression model. Using this model, we were able to detect the exercise event with a sensitivity of 97.2% and a specificity of 99.5%. Second, from this same study, we show how patients’ glucose declined during the exercise event and we present results from in silico modeling that demonstrate how including an exercise model in the glucoregulatory model improves the estimation of the drop in glucose during exercise. Last, we present an exercise dosing adjustment algorithm and describe parameter tuning and performance using an in silico glucoregulatory model during an exercise event. PMID:26438720

  4. Artificial Limbs

    MedlinePlus

    ... you are missing an arm or leg, an artificial limb can sometimes replace it. The device, which is ... activities such as walking, eating, or dressing. Some artificial limbs let you function nearly as well as before.

  5. Apical access and closure devices for transapical transcatheter heart valve procedures.

    PubMed

    Ferrari, Enrico

    2016-01-01

    The majority of transcatheter aortic valve implantations, structural heart procedures and the newly developed transcatheter mitral valve repair and replacement are traditionally performed either through a transfemoral or a transapical access site, depending on the presence of severe peripheral vascular disease or anatomic limitations. The transapical approach, which carries specific advantages related to its antegrade nature and the short distance between the introduction site and the cardiac target, is traditionally performed through a left anterolateral mini-thoracotomy and requires rib retractors, soft tissue retractors and reinforced apical sutures to secure, at first, the left ventricular apex for the introduction of the stent-valve delivery systems and then to seal the access site at the end of the procedure. However, despite the advent of low-profile apical sheaths and newly designed delivery systems, the apical approach represents a challenge for the surgeon, as it has the risk of apical tear, life-threatening apical bleeding, myocardial damage, coronary damage and infections. Last but not least, the use of large-calibre stent-valve delivery systems and devices through standard mini-thoracotomies compromises any attempt to perform transapical transcatheter structural heart procedures entirely percutaneously, as happens with the transfemoral access site, or via a thoracoscopic or a miniaturised video-assisted percutaneous technique. During the past few years, prototypes of apical access and closure devices for transapical heart valve procedures have been developed and tested to make this standardised successful procedure easier. Some of them represent an important step towards the development of truly percutaneous transcatheter transapical heart valve procedures in the clinical setting. PMID:26900765

  6. Apical access and closure devices for transapical transcatheter heart valve procedures.

    PubMed

    Ferrari, Enrico

    2016-01-01

    The majority of transcatheter aortic valve implantations, structural heart procedures and the newly developed transcatheter mitral valve repair and replacement are traditionally performed either through a transfemoral or a transapical access site, depending on the presence of severe peripheral vascular disease or anatomic limitations. The transapical approach, which carries specific advantages related to its antegrade nature and the short distance between the introduction site and the cardiac target, is traditionally performed through a left anterolateral mini-thoracotomy and requires rib retractors, soft tissue retractors and reinforced apical sutures to secure, at first, the left ventricular apex for the introduction of the stent-valve delivery systems and then to seal the access site at the end of the procedure. However, despite the advent of low-profile apical sheaths and newly designed delivery systems, the apical approach represents a challenge for the surgeon, as it has the risk of apical tear, life-threatening apical bleeding, myocardial damage, coronary damage and infections. Last but not least, the use of large-calibre stent-valve delivery systems and devices through standard mini-thoracotomies compromises any attempt to perform transapical transcatheter structural heart procedures entirely percutaneously, as happens with the transfemoral access site, or via a thoracoscopic or a miniaturised video-assisted percutaneous technique. During the past few years, prototypes of apical access and closure devices for transapical heart valve procedures have been developed and tested to make this standardised successful procedure easier. Some of them represent an important step towards the development of truly percutaneous transcatheter transapical heart valve procedures in the clinical setting.

  7. Experimental Studies on Amount of Snowfall by Crystal Growth in an Artificial Snowfall Device

    NASA Astrophysics Data System (ADS)

    Seki, Mitsuo; Umezawa, Kouichi; Abe, Osamu

    A series of experiments was conducted to estimate the amount of snowfall of dendrite-type crystals produced by an artificial snowfall device that uses the rotary ventilation mesh filter method. An expression is proposed in this paper for the amount of the snowfall. The amount of snowfall (Gs) can be expressed as Gs = ηs Vai ΔW , where ΔW is effective water content in the crystal growth, Vai is air mass flow and ηs is snowfall efficiency. The effective water content in the crystal growth (ΔW) is defined as the difference between the specific cloud water content and ice saturation vapor density. The rotary ventilation mesh filter method used in this work had a snowfall efficiency of about 90%. Even for a large amount of cloud water content, we observed only a very few super-cooled cloud droplets on snow crystals. Therefore, we can deduce that the cloud water content should contribute to crystal growth directly. We report here measurements of snowfall as a function of several input parameters and verify the validity of the proposed relationship.

  8. Adhesion control by inflation: implications from biology to artificial attachment device

    NASA Astrophysics Data System (ADS)

    Dening, Kirstin; Heepe, Lars; Afferrante, Luciano; Carbone, Giuseppe; Gorb, Stanislav N.

    2014-08-01

    There is an increasing demand for materials that incorporate advanced adhesion properties, such as an ability to adhere in a reversible and controllable manner. In biological systems, these features are known from adhesive pads of the tree frog, Litoria caerulea, and the bush-cricket, Tettigonia viridissima. These species have convergently developed soft, hemispherically shaped pads that might be able to control their adhesion through active changing the curvature of the pad. Inspired by these biological systems, an artificial model system is developed here. It consists of an inflatable membrane clamped to the metallic cylinder and filled with air. Pull-off force measurements of the membrane surface were conducted in contact with the membrane at five different radii of curvature r c with (1) a smooth polyvinylsiloxane membrane and (2) mushroom-shaped adhesive microstructured membrane made of the same polymer. The hypothesis that an increased internal pressure, acting on the membrane, reduces the radius of the membrane curvature, resulting in turn in a lower pull-off force, is verified. Such an active control of adhesion, inspired by biological models, will lead to the development of industrial pick-and-drop devices with controllable adhesive properties.

  9. High-Intensity Transient Signals in the Outflow Graft and Thrombosis of a HeartWare Left Ventricular Assist Device.

    PubMed

    Dimitrov, Kamen; Riebandt, Julia; Haberl, Thomas; Wiedemann, Dominik; Simon, Paul; Laufer, Günther; Schima, Heinrich; Zimpfer, Daniel

    2016-03-01

    We report the echocardiographic detection of microbubbles in the outflow prosthesis of a HeartWare HVAD left ventricular assist device using transthoracic echocardiography. In this case it was a specific sign associated with device thrombosis that resolved after successful treatment with systemic thrombolysis. PMID:26897237

  10. Eliminating artificial trans fatty acids in Argentina: estimated effects on the burden of coronary heart disease and costs

    PubMed Central

    Elorriaga, Natalia; Garay, Osvaldo U; Poggio, Rosana; Caporale, Joaquin; Matta, Maria G; Augustovski, Federico; Pichon-Riviere, Andres; Mozaffarian, Dariush

    2015-01-01

    Abstract Objective To estimate the impact of Argentine policies to reduce trans fatty acids (TFA) on coronary heart disease (CHD), disability-adjusted life years (DALYs) and associated health-care costs. Methods We estimated the baseline intake of TFA before 2004 to be 1.5% of total energy intake. We built a policy model including baseline intake of TFA, the oils and fats used to replace artificial TFAs, the clinical effect of reducing artificial TFAs and the costs and DALYs saved due to averted CHD events. To calculate the percentage of reduction of CHD, we calculated CHD risks on a population-based sample before and after implementation. The effect of the policies was modelled in three ways, based on projected changes: (i) in plasma lipid profiles; (ii) in lipid and inflammatory biomarkers; and (iii) the results of prospective cohort studies. We also estimated the present economic value of DALYs and associated health-care costs of coronary heart disease averted. Findings We estimated that projected changes in lipid profile would avert 301 deaths, 1066 acute CHD events, 5237 DALYs and 17 million United States dollars (US$) in health-care costs annually. Based on the adverse effects of TFA intake reported in prospective cohort studies, 1517 deaths, 5373 acute CHD events, 26 394 DALYs and US$ 87 million would be averted annually. Conclusion Even under the most conservative scenario, reduction of TFA intake had a substantial effect on public health. These findings will help inform decision-makers in Argentina and other countries on the potential public health and economic impact of this policy. PMID:26478625

  11. Remission of chronic anthracycline-induced heart failure with support from a continuous-flow left ventricular assist device.

    PubMed

    Khan, Nadeem; Husain, Syed Arman; Husain, Syed Iman; Khalaf, Natalia; George, Joggy; Raissi, Farshad; Segura, Ana Maria; Kar, Biswajit; Bogaev, Roberta C; Frazier, O H

    2012-01-01

    We report the case of a patient who had chronic anthracycline-induced cardiomyopathy that was reversed after treatment with a left ventricular assist device. A 29-year-old woman had undergone anthracycline-based chemotherapy as a teenager in 1991 and 1992 and received a diagnosis of dilated cardiomyopathy 10 years later. Optimal medical therapy had initially controlled the symptoms of heart failure. However, in June 2006, the symptoms worsened to New York Heart Association functional class IV status. We implanted a continuous-flow left ventricular assist device as a bridge to cardiac transplantation; of note, a left ventricular core biopsy at that time showed no replacement fibrosis. The patient's clinical status improved thereafter, enabling left ventricular assist device ex-plantation after 17 months. To our knowledge, this is the first report of the use of left ventricular assist device support to reverse chronic anthracycline-induced heart failure.

  12. RF communication with implantable wireless device: effects of beating heart on performance of miniature antenna

    PubMed Central

    Borghi, Alessandro; Bahmanyar, Mohammad Reza; McLeod, Christopher N.; Navaratnarajah, Manoraj; Yacoub, Magdi; Toumazou, Christofer

    2014-01-01

    The frequency response of an implantable antenna is key to the performance of a wireless implantable sensor. If the antenna detunes significantly, there are substantial power losses resulting in loss of accuracy. One reason for detuning is because of a change in the surrounding environment of an antenna. The pulsating anatomy of the human heart constitutes such a changing environment, so detuning is expected but this has not been quantified dynamically before. Four miniature implantable antennas are presented (two different geometries) along with which are placed within the heart of living swine the dynamic reflection coefficients. These antennas are designed to operate in the short range devices frequency band (863–870 MHz) and are compatible with a deeply implanted cardiovascular pressure sensor. The measurements recorded over 27 seconds capture the effects of the beating heart on the frequency tuning of the implantable antennas. When looked at in the time domain, these effects are clearly physiological and a combination of numerical study and posthumous autopsy proves this to be the case, while retrospective simulation confirms this hypothesis. The impact of pulsating anatomy on antenna design and the need for wideband implantable antennas is highlighted. PMID:26609377

  13. Molecular changes after left ventricular assist device support for heart failure.

    PubMed

    Birks, Emma J

    2013-08-30

    Heart failure is associated with remodeling that consists of adverse cellular, structural, and functional changes in the myocardium. Until recently, this was thought to be unidirectional, progressive, and irreversible. However, irreversibility has been shown to be incorrect because complete or partial reversal can occur that can be marked after myocardial unloading with a left ventricular assist device (LVAD). Patients with chronic advanced heart failure can show near-normalization of nearly all structural abnormalities of the myocardium or reverse remodeling after LVAD support. However, reverse remodeling does not always equate with clinical recovery. The molecular changes occurring after LVAD support are reviewed, both those demonstrated with LVAD unloading alone in patients bridged to transplantation and those occurring in the myocardium of patients who have recovered enough myocardial function to have the device removed. Reverse remodeling may be attributable to a reversal of the pathological mechanisms that occur in remodeling or the generation of new pathways. A reduction in cell size occurs after LVAD unloading, which does not necessarily correlate with improved cardiac function. However, some of the changes in both the cardiac myocyte and the matrix after LVAD support are specific to myocardial recovery. In the myocyte, increases in the cytoskeletal proteins and improvements in the Ca²⁺ handling pathway seem to be specifically associated with myocardial recovery. Changes in the matrix are complex, but excessive scarring appears to limit the ability for recovery, and the degree of fibrosis in the myocardium at the time of implantation may predict the ability to recover.

  14. Sensing magnetic flux density of artificial neurons with a MEMS device.

    PubMed

    Tapia, Jesus A; Herrera-May, Agustin L; García-Ramírez, Pedro J; Martinez-Castillo, Jaime; Figueras, Eduard; Flores, Amira; Manjarrez, Elías

    2011-04-01

    We describe a simple procedure to characterize a magnetic field sensor based on microelectromechanical systems (MEMS) technology, which exploits the Lorentz force principle. This sensor is designed to detect, in future applications, the spiking activity of neurons or muscle cells. This procedure is based on the well-known capability that a magnetic MEMS device can be used to sense a small magnetic flux density. In this work, an electronic neuron (FitzHugh-Nagumo) is used to generate controlled spike-like magnetic fields. We show that the magnetic flux density generated by the hardware of this neuron can be detected with a new MEMS magnetic field sensor. This microdevice has a compact resonant structure (700 × 600 × 5 μm) integrated by an array of silicon beams and p-type piezoresistive sensing elements, which need an easy fabrication process. The proposed microsensor has a resolution of 80 nT, a sensitivity of 1.2 V.T(-1), a resonant frequency of 13.87 kHz, low power consumption (2.05 mW), quality factor of 93 at atmospheric pressure, and requires a simple signal processing circuit. The importance of our study is twofold. First, because the artificial neuron can generate well-controlled magnetic flux density, we suggest it could be used to analyze the resolution and performance of different magnetic field sensors intended for neurobiological applications. Second, the introduced MEMS magnetic field sensor may be used as a prototype to develop new high-resolution biomedical microdevices to sense magnetic fields from cardiac tissue, nerves, spinal cord, or the brain.

  15. Real time heart rate variability assessment from Android smartphone camera photoplethysmography: Postural and device influences.

    PubMed

    Guede-Fernandez, F; Ferrer-Mileo, V; Ramos-Castro, J; Fernandez-Chimeno, M; Garcia-Gonzalez, M A

    2015-01-01

    The aim of this paper is to present a smartphone based system for real-time pulse-to-pulse (PP) interval time series acquisition by frame-to-frame camera image processing. The developed smartphone application acquires image frames from built-in rear-camera at the maximum available rate (30 Hz) and the smartphone GPU has been used by Renderscript API for high performance frame-by-frame image acquisition and computing in order to obtain PPG signal and PP interval time series. The relative error of mean heart rate is negligible. In addition, measurement posture and the employed smartphone model influences on the beat-to-beat error measurement of heart rate and HRV indices have been analyzed. Then, the standard deviation of the beat-to-beat error (SDE) was 7.81 ± 3.81 ms in the worst case. Furthermore, in supine measurement posture, significant device influence on the SDE has been found and the SDE is lower with Samsung S5 than Motorola X. This study can be applied to analyze the reliability of different smartphone models for HRV assessment from real-time Android camera frames processing.

  16. Impact of Vice President Cheney on public interest in left ventricular assist devices and heart transplantation.

    PubMed

    Pandey, Ambarish; Abdullah, Kazeen; Drazner, Mark H

    2014-05-01

    Although celebrity illnesses attract a significant amount of media attention in the United States, there are few studies that have looked at how celebrity health conditions impact the awareness of the illness in the general population. Recently, Vice President Cheney underwent left ventricular assist device (LVAD) implantation and subsequently a cardiac transplant. The aim of this study was to determine whether there was evidence of increased interest in these 2 procedures as assessed by social media. We determined the relative frequency of Google searches for LVAD and heart transplantation from 2004 to 2013 using Google trends. We also counted the number of YouTube videos and Twitter messages posted monthly concerning LVADs over a 7-year time frame. There was a significant spike in the Google search interest for LVAD and heart transplantation in the month when Vice President Cheney underwent the respective procedure. Similarly, there was a large increase in YouTube videos and Twitter messages concerning LVADs shortly after he was implanted. In total, these data support the concept that a public figure's illness can significantly influence the public's interest in that condition and its associated therapies.

  17. Long-term continuous-flow left ventricular assist devices (LVAD) as bridge to heart transplantation

    PubMed Central

    Pozzi, Matteo; Giraud, Raphaël; Tozzi, Piergiorgio; Bendjelid, Karim; Robin, Jacques; Meyer, Philippe; Obadia, Jean François

    2015-01-01

    Heart transplantation (HTx) is the treatment of choice for end-stage heart failure but the limited availability of heart’s donors still represents a major issue. So long-term mechanical circulatory support (MCS) has been proposed as an alternative treatment option to assist patients scheduled on HTx waiting list bridging them for a variable time period to cardiac transplantation—the so-called bridge-to-transplantation (BTT) strategy. Nowadays approximately 90% of patients being considered for MCS receive a left ventricular assist device (LVAD). In fact, LVAD experienced several improvements in the last decade and the predominance of continuous-flow over pulsatile-flow technology has been evident since 2008. The aim of the present report is to give an overview of continuous-flow LVAD utilization in the specific setting of the BTT strategy taking into consideration the most representative articles of the scientific literature and focusing the attention on the evolution, clinical outcomes, relevant implications on the HTx strategy and future perspectives of the continuous-flow LVAD technology. PMID:25922736

  18. [The influence of hereditary thrombophilic mechanisms on the degree of permanent intravascular coagulation in patients with artificial heart valves].

    PubMed

    Vavilova, T V; Sirotkina, O V; Razorenov, G I; Razorenova, T S; Emanuél', V L; Gritsenko, V V; Orlovskiĭ, P I; Doĭnikov, D N; Sharafutdinov, V E; Karpov, S A; Kuznetsov, A A; Kadinskaia, M I

    2004-01-01

    The genotyping of 40 patients with artificial heart valves (AHV) was performed after prosthesis of the mitral and aotic valves with bicuspid AHV (Medinzh-2 and CarboMedics). The patients took phenylin and varfarin. The patients' genotype was estimated by the thrombophylic genes: factor V Leiden (FVL), prothrombin G20210A, methylene tetrahydrofolate reductase C677T, G/A--455FGB, 4G/5G PAI-1, PI A1/A2 GPIIIa. The genes determining the thrombocytic activity or the vascular wall state substantially influence the third degree of the intensity of the permanent intravascular coagulation (PIC-3) independent of the degree of correction of hemostasis of oral anticoagulants. The addition of anti-aggregants to therapy is the only that can normalize functional activity of thrombocytes in patients with AHV having such defects. The laboratory detection of the genetic defects is of great practical importance for the determination of risk groups of formation of PIC-3 and the strategy of antithrombotic protection of patients with AHV. PMID:15651704

  19. Canadian Cardiovascular Society Consensus Conference guidelines on heart failure, update 2009: Diagnosis and management of right-sided heart failure, myocarditis, device therapy and recent important clinical trials

    PubMed Central

    Howlett, Jonathan G; McKelvie, Robert S; Arnold, J Malcolm O; Costigan, Jeannine; Dorian, Paul; Ducharme, Anique; Estrella-Holder, Estrellita; Ezekowitz, Justin A; Giannetti, Nadia; Haddad, Haissam; Heckman, George A; Herd, Anthony M; Isaac, Debra; Jong, Philip; Kouz, Simon; Liu, Peter; Mann, Elizabeth; Moe, Gordon W; Tsuyuki, Ross T; Ross, Heather J; White, Michel

    2009-01-01

    The Canadian Cardiovascular Society published a comprehensive set of recommendations on the diagnosis and management of heart failure in January 2006. Based on feedback obtained through a national program of heart failure workshops and through active solicitation of stakeholders, several topics were identified because of their importance to the practicing clinician. Topics chosen for the present update include best practices for the diagnosis and management of right-sided heart failure, myocarditis and device therapy, and a review of recent important or landmark clinical trials. These recommendations were developed using the structured approach for the review and assessment of evidence adopted and previously described by the Society. The present update has been written from a clinical perspective to provide a user-friendly and practical approach. Specific clinical questions that are addressed include: What is right-sided heart failure and how should one approach the diagnostic work-up? What other clinical entities may masquerade as this nebulous condition and how can we tell them apart? When should we be concerned about the presence of myocarditis and how quickly should patients with this condition be referred to an experienced centre? Among the myriad of recently published landmark clinical trials, which ones will impact our standards of clinical care? The goals are to aid physicians and other health care providers to optimally treat heart failure patients, resulting in a measurable impact on patient health and clinical outcomes in Canada. PMID:19214293

  20. Acute Effects of a Therapeutic Mobility Device on Physical Activity and Heart Rate in Children with Down Syndrome

    ERIC Educational Resources Information Center

    Hauck, Janet L.; Ulrich, Dale A.

    2015-01-01

    Purpose: The purpose of this feasibility study was to provide an opportunity to increase physical activity (PA) and heart rate (HR) for children with Down syndrome (DS) during unstructured group exercise utilizing a riding device called the Power Pumper®. Method: Twenty-four children aged 5 to 7 years old participated in this case-control study,…

  1. Experimental method to reveal the effect of rotor magnet size and air gap on artificial heart driving motor torque and efficiency.

    PubMed

    Qian, K X; Yuan, H Y; Ru, W M; Zeng, P

    2002-01-01

    To investigate experimentally the effect of rotor magnet design on artificial heart driving motor performance, seven rotors with different magnet lengths or thicknesses, as well as different peripheral angles, were manufactured and tested in the same motor stator with different rotating speeds. The input power (voltage and current) and output torque were measured and the motor efficiency was computed. The results demonstrated that the reduction of rotor magnet size and the enlargement of the air gap between the rotor magnets and the stator coil core have no significant effect on motor efficiency, but will reduce the torque value on which the motor achieves the highest efficiency; it could be remedied however by increasing the rotating speed, because the torque at the high efficiency point will increase along with the rotating speed. These results may provide a basis for developing small rotor magnets, large air gap and high efficiency motors for driving an artificial heart pump.

  2. [Biomarkers of inflammation in patients with chronic heart failure and implanted devices for cardiac resynchronization therapy].

    PubMed

    Kuznetsov, V A; Soldatova, A M; Enina, T N; Shebeko, P V; Rychkov, A Iu; Mel'nikov, N N; Zateĭshchikov, D A

    2012-01-01

    The aim of the study was to assess the relationship between N-terminal pro-brain natriuretic peptide (NT-proBNP) and inflammatory markers in patients with congestive heart failure (CHF) treated with cardiac resynchronization therapy (CRT). 97 patients (age 54.9+/-9.9 years; 87% men) with implanted CRT devices (median period after implantation 19.9+/-19.3 months) were enrolled. According to NT-proBNP level patients were divided into tertiles: first (n=36) - less than 848 pg/ml, second (n=29) - from 848 to 2936 pg/ml, and third (n=32) - more than 2936 pg/ml. We didnt find a relationship between inflammatory mediators, NT-probNP level and time after implantation. In the total group NT-proBNP significantly correlated with structural and functional parameters of the heart. In the first group in comparison with the third group levels of IL-6 were lower (pI-III=0.019) and levels of IL-l - higher (pI-III=0.006). IL-10, CRP, TNF- did not differ between groups. In the first group IL-l straightly correlated with IL-6, TNF- , IL-10 and left ventricular ejection fraction (LVEF), in the third group IL-6 straightly correlated with CRP, while correlation of IL-l with LVEF became negative. We suppose that in patients with mild HF IL-l can play an adaptive role. High levels of IL-6, CRP probably can be used as markers of CHF progression in patients treated with CRT. PMID:23098397

  3. [First successful bridge to cardiac transplantation in Chile using the Heart Mate II device. Report of one case].

    PubMed

    Bunster, Nicolás; Villavicencio, Mauricio; Lim, Jongsung; Donoso, Erika; Gajardo, Francesca; Rossel, Víctor

    2014-04-01

    Implantable ventricular assist devices are an effective treatment option for end-stage heart failure patients as a bridge to cardiac transplantation, to improve the clinical condition and organ function allowing discharge from the hospital to await for transplantation. The second alternative is to use the device as destination therapy for patients with contraindications for cardiac transplantation, in whom it is maintained indefinitely. We report a 43-year-old patient, with a dilated cardiomyopathy, severe left ventricular dysfunction and advanced heart failure. A ventricular assist device Heart Mate II©, as a bridge to transplantation, was implanted to the patient in the United States. It was explanted for the first time in Chile at the National Thorax Institute. Heart transplantation was performed using the bicaval technique. Induction of immunosuppression was done with basiliximab. Generic immunosuppression was carried out with cyclosporine, mycophenolate mofetil and prednisone. Postoperatively the patient evolved with right femoral vein thrombosis in the femoral cannulation site, phlegmasia alba dolens, rhabdomyolysis, oliguric acute renal failure, which required renal replacement therapy, severe shock, with high requirements of vasoactive drugs and need for mechanical ventilation. He required a reoperation for hemothorax and had an Enterobacter pneumonia. After a period of serious illness, he began a gradual recovery and was discharged from the hospital after 58 days. After two years, he remains in functional class I, with a normal graft function.

  4. Device exchange in HeartMate II recipients: long-term outcomes and risk of thrombosis recurrence.

    PubMed

    Levin, Allison P; Uriel, Nir; Takayama, Hiroo; Mody, Kanika P; Ota, Takeyoshi; Yuzefpolskaya, Melana; Colombo, Paolo C; Garan, Arthur R; Dionizovik-Dimanovski, Marija; Sladen, Robert N; Naka, Yoshifumi; Jorde, Ulrich P

    2015-01-01

    Successful long-term use of the HeartMate II (HM II) left ventricular assist device has become commonplace but may be complicated by mechanical failure, infection, or thrombosis necessitating device exchange (DE). A subcostal approach to device exchange with motor exchange only is less traumatic, but long-term outcomes have not been reported. A retrospective chart review of all patients who required HM II to HM II device exchange at our institution was conducted. Of the 232 HM II patients implanted between January 2008 and July 2013, 28 required 36 device exchanges during a follow-up of 33.72 ± 17.25 months. The Kaplan-Meier 1 year survival was 63% for sternotomy exchanges and 100% for subcostal exchanges. Twenty-one exchanges were performed for initial or recurring device thrombosis. Although there was no difference in the risk of subsequent thrombosis after subcostal versus sternotomy exchange, the overall risk of recurring device thrombosis after device exchange for the same was high (31%). HM II device exchange via the subcostal approach has excellent short- and long-term outcomes. Device exchange performed for thrombosis is associated with a high recurrence risk irrespective of surgical approach.

  5. Ventricular Assist Device in Single-Ventricle Heart Disease and a Superior Cavopulmonary Anastomosis.

    PubMed

    Niebler, Robert A; Shah, Tejas K; Mitchell, Michael E; Woods, Ronald K; Zangwill, Steven D; Tweddell, James S; Berger, Stuart; Ghanayem, Nancy S

    2016-02-01

    Our objective is to describe the use of a ventricular assist device (VAD) in single-ventricle patients with circulatory failure following superior cavopulmonary anastomosis (SCPA). We performed a retrospective chart review of all single-ventricle patients supported with a VAD following SCPA. Implantation techniques, physiologic parameters while supported, medical and surgical interventions postimplant, and outcomes were reviewed. Four patients were supported with an EXCOR Pediatric (Berlin Heart Inc., The Woodlands, TX, USA) following SCPA for a median duration of 10.5 days (range 9-312 days). Selective excision of trabeculae and chords facilitated apical cannulation in all patients without inflow obstruction. There were two pump exchanges in the one patient supported for 312 days. Two patients were evaluated by cardiac catheterization while supported. Three of four patients were successfully bridged to transplantation. One patient died while supported. All patients had significant bleeding at the time of transplantation, and one required posttransplant extracorporeal membrane oxygenation with subsequent full recovery. VAD support can provide a successful bridge to transplantation in patients with single-ventricle circulation following SCPA. A thorough understanding of the challenges encountered during this support is necessary for successful outcomes.

  6. Concurrent Left Ventricular Assist Device (LVAD) Implantation and Percutaneous Temporary RVAD Support via CardiacAssist Protek-Duo TandemHeart to Preempt Right Heart Failure.

    PubMed

    Schmack, Bastian; Weymann, Alexander; Popov, Aron-Frederik; Patil, Nikhil Prakash; Sabashnikov, Anton; Kremer, Jamila; Farag, Mina; Brcic, Andreas; Lichtenstern, Christoph; Karck, Matthias; Ruhparwar, Arjang

    2016-01-01

    Right ventricular failure (RVF) is an unfortunate complication that continues to limit outcomes following durable left ventricular assist device (LVAD) implantation. Despite several 'RVF risk scores' having been proposed, preoperative prediction of post-LVAD RVF remains a guesstimate at best. Current strategies for institution of temporary RVAD support are invasive, necessitate additional re-thoracotomy, restrict postoperative mobilization, and/or entail prolonged retention of prosthetic material in-situ. The authors propose a novel surgical strategy comprising simultaneous implantation of a permanent LVAD and percutaneous TandemHeart® plus ProtekDuo® to provide temporary RVAD support and preempt RVF in patients with impaired RV function. PMID:27145697

  7. Closed-loop artificial pancreas systems: physiological input to enhance next-generation devices.

    PubMed

    Kudva, Yogish C; Carter, Rickey E; Cobelli, Claudio; Basu, Rita; Basu, Ananda

    2014-01-01

    To provide an understanding of both the preclinical and clinical aspects of closed-loop artificial pancreas systems, we provide a discussion of this topic as part of this two-part Bench to Clinic narrative. Here, the Bench narrative provides an in-depth understanding of insulin-glucose-glucagon physiology in conditions that mimic the free-living situation to the extent possible in type 1 diabetes that will help refine and improve future closed-loop system algorithms. In the Clinic narrative, Doyle and colleagues compare and evaluate technology used in current closed-loop studies to gain further momentum toward outpatient trials and eventual approval for widespread use.

  8. [Percutaneous implantation of a left ventricular restoration device [Parachute(TM)] for the treatment of ischemic heart failure].

    PubMed

    Ielasi, Alfonso; Tespili, Maurizio; Repossini, Alberto; Scopelliti, Pasquale; Paganoni, Silvia; Cafro, Andrea; Silvestro, Antonio; Personeni, Davide; Saino, Antonio; Muneretto, Claudio

    2015-01-01

    Congestive heart failure secondary to myocardial infarction is associated with significant morbidity and mortality despite currently available therapies. A novel catheter-based left ventricular partitioning device (ParachuteTM, CardioKinetix, Inc., Menlo Park, CA) is currently available for the treatment of patients with severe systolic dysfunction after antero-apical myocardial infarction with regional wall motion abnormalities. Preliminary clinical data showed that the ParachuteTM implantation could be associated with favorable clinical and left ventricular hemodynamic improvements post-implantation. Here, we present the case of a patient with symptomatic congestive heart failure after myocardial infarction implanted with the ParachuteTM device and we briefly review the current literature on this left ventricular partitioning system.

  9. [Percutaneous implantation of a left ventricular restoration device [Parachute(TM)] for the treatment of ischemic heart failure].

    PubMed

    Ielasi, Alfonso; Tespili, Maurizio; Repossini, Alberto; Scopelliti, Pasquale; Paganoni, Silvia; Cafro, Andrea; Silvestro, Antonio; Personeni, Davide; Saino, Antonio; Muneretto, Claudio

    2015-01-01

    Congestive heart failure secondary to myocardial infarction is associated with significant morbidity and mortality despite currently available therapies. A novel catheter-based left ventricular partitioning device (ParachuteTM, CardioKinetix, Inc., Menlo Park, CA) is currently available for the treatment of patients with severe systolic dysfunction after antero-apical myocardial infarction with regional wall motion abnormalities. Preliminary clinical data showed that the ParachuteTM implantation could be associated with favorable clinical and left ventricular hemodynamic improvements post-implantation. Here, we present the case of a patient with symptomatic congestive heart failure after myocardial infarction implanted with the ParachuteTM device and we briefly review the current literature on this left ventricular partitioning system. PMID:25689752

  10. Cardiac supporting device using artificial rubber muscle: preliminary study to active dynamic cardiomyoplasty.

    PubMed

    Saito, Yoshiaki; Suzuki, Yasuyuki; Goto, Takeshi; Daitoku, Kazuyuki; Minakawa, Masahito; Fukuda, Ikuo

    2015-12-01

    Dynamic cardiomyoplasty is a surgical treatment that utilizes the patient's skeletal muscle to support circulation. To overcome the limitations of autologous skeletal muscles in dynamic cardiomyoplasty, we studied the use of a wrapped-type cardiac supporting device using pneumatic muscles. Four straight rubber muscles (Fluidic Muscle, FESTO, Esslingen, Germany) were used and connected to pressure sensors, solenoid valves, a controller and an air compressor. The driving force was compressed air. A proportional-integral-derivative system was employed to control the device movement. An overflow-type mock circulation system was used to analyze the power and the controllability of this new device. The device worked powerfully with pumped flow against afterload of 88 mmHg, and the beating rate and contraction/dilatation time were properly controlled using simple software. Maximum pressure inside the ventricle and maximum output were 187 mmHg and 546.5 ml/min, respectively, in the setting of 50 beats per minute, a contraction/dilatation ratio of 1:2, a preload of 18 mmHg, and an afterload of 88 mmHg. By changing proportional gain, contraction speed could be modulated. This study showed the efficacy and feasibility of a pneumatic muscle for use in a cardiac supporting device.

  11. Biotribological evaluation of artificial disc arthroplasty devices: influence of loading and kinematic patterns during in vitro wear simulation

    PubMed Central

    Yue, James J.; Garcia, Rolando; Basson, Janet; Schwiesau, Jens; Fritz, Bernhard; Blömer, Wilhelm

    2008-01-01

    Wear simulation is an essential pre-clinical method to predict the mid- and long-term clinical wear behavior of newly introduced devices for total disc arthroplasty. The main requirement of a suitable method for spinal wear simulation has to be the ability to distinguish between design concepts and allow for a direct comparison of predicate devices. The objective of our study was to investigate the influence of loading and kinematic patterns based on two different protocols for spinal wear simulation (ISO/FDIS 18192-1 (2006) and ASTM F2423-05). In vitro wear simulation was performed with six activ® L lumbar artificial disc devices (Aesculap Tuttlingen, Germany). The applied kinematic pattern of movement was multidirectional for ISO (elliptic track) and unidirectional with a curvilinear shape for ASTM. Testing was done for 10 million cycles in the ISO loading mode and afterwards with the same specimens for 5 million cycles according to the ASTM protocol with a customized six-station servohydraulic spinal wear simulator (EndoLab Thansau, Germany). Gravimetrical and geometrical wear assessment, a slide track analysis correlated to an optical surface characterization, and an estimation of particle size and morphology were performed. The gravimetric wear rate for the first 10 million cycles was ISOinitial = 2.7 ± 0.3 mg/million cycles. During the ASTM test period (10–15 million cycles) a gravimetric wear rate of 0.14 ± 0.06 mg/million cycles was estimated. The wear rates between the ISO and ASTM driven simulations differ substantially (approximately 20-fold) and statistical analysis demonstrates a significant difference (p < 0.001) between the test groups. The main explanation of divergency between ISO and ASTM driven wear simulations is the multidirectional pattern of movement described in the ISO document resulting in a cross-shear stress on the polyethylene material. Due to previous retrieval observations, it seems to be very unlikely that a lumbar

  12. Artificial retina: the multichannel processing of the mammalian retina achieved with a neuromorphic asynchronous light acquisition device.

    PubMed

    Lorach, Henri; Benosman, Ryad; Marre, Olivier; Ieng, Sio-Hoi; Sahel, José A; Picaud, Serge

    2012-12-01

    Objective. Accurate modeling of retinal information processing remains a major challenge in retinal physiology with applications in visual rehabilitation and prosthetics. Most of the current artificial retinas are fed with static frame-based information, losing thereby the fundamental asynchronous features of biological vision. The objective of this work is to reproduce the spatial and temporal properties of the majority of ganglion cell (GC) types in the mammalian retina. Approach. Here, we combined an asynchronous event-based light sensor with a model pulling nonlinear subunits to reproduce the parallel filtering and temporal coding occurring in the retina. We fitted our model to physiological data and were able to reconstruct the spatio-temporal responses of the majority of GC types previously described in the mammalian retina (Roska et al 2006 J. Neurophysiol. 95 3810-22). Main results. Fitting of the temporal and spatial components of the response was achieved with high coefficients of determination (median R(2) = 0.972 and R(2) = 0.903, respectively). Our model provides an accurate temporal precision with a reliability of only few milliseconds-peak of the distribution at 5 ms-similar to biological retinas (Berry et al 1997 Proc. Natl Acad. Sci. USA 94 5411-16; Gollisch and Meister 2008 Science 319 1108-11). The spiking statistics of the model also followed physiological measurements (Fano factor: 0.331). Significance. This new asynchronous retinal model therefore opens new perspectives in the development of artificial visual systems and visual prosthetic devices.

  13. Closed-Loop Artificial Pancreas Systems: Physiological Input to Enhance Next-Generation Devices

    PubMed Central

    Kudva, Yogish C.; Carter, Rickey E.; Cobelli, Claudio

    2014-01-01

    To provide an understanding of both the preclinical and clinical aspects of closed-loop artificial pancreas systems, we provide a discussion of this topic as part of this two-part Bench to Clinic narrative. Here, the Bench narrative provides an in-depth understanding of insulin-glucose-glucagon physiology in conditions that mimic the free-living situation to the extent possible in type 1 diabetes that will help refine and improve future closed-loop system algorithms. In the Clinic narrative, Doyle and colleagues compare and evaluate technology used in current closed-loop studies to gain further momentum toward outpatient trials and eventual approval for widespread use. PMID:24757225

  14. Accuracy of a Wrist-Worn Wearable Device for Monitoring Heart Rates in Hospital Inpatients: A Prospective Observational Study

    PubMed Central

    Kroll, Ryan R; Boyd, J Gordon

    2016-01-01

    Background As the sensing capabilities of wearable devices improve, there is increasing interest in their application in medical settings. Capabilities such as heart rate monitoring may be useful in hospitalized patients as a means of enhancing routine monitoring or as part of an early warning system to detect clinical deterioration. Objective To evaluate the accuracy of heart rate monitoring by a personal fitness tracker (PFT) among hospital inpatients. Methods We conducted a prospective observational study of 50 stable patients in the intensive care unit who each completed 24 hours of heart rate monitoring using a wrist-worn PFT. Accuracy of heart rate recordings was compared with gold standard measurements derived from continuous electrocardiographic (cECG) monitoring. The accuracy of heart rates measured by pulse oximetry (Spo2.R) was also measured as a positive control. Results On a per-patient basis, PFT-derived heart rate values were slightly lower than those derived from cECG monitoring (average bias of −1.14 beats per minute [bpm], with limits of agreement of 24 bpm). By comparison, Spo2.R recordings produced more accurate values (average bias of +0.15 bpm, limits of agreement of 13 bpm, P<.001 as compared with PFT). Personal fitness tracker device performance was significantly better in patients in sinus rhythm than in those who were not (average bias −0.99 bpm vs −5.02 bpm, P=.02). Conclusions Personal fitness tracker–derived heart rates were slightly lower than those derived from cECG monitoring in real-world testing and not as accurate as Spo2.R-derived heart rates. Performance was worse among patients who were not in sinus rhythm. Further clinical evaluation is indicated to see if PFTs can augment early warning systems in hospitals. Trial Registration ClinicalTrials.gov NCT02527408; https://clinicaltrials.gov/ct2/show/NCT02527408 (Archived by WebCite at  http://www.webcitation.org/6kOFez3on) PMID:27651304

  15. Quantification of formation and remineralization of artificial enamel lesions with a new portable fluorescence device.

    PubMed

    al-Khateeb, S; ten Cate, J M; Angmar-Månsson, B; de Josselin de Jong, E; Sundström, G; Exterkate, R A; Oliveby, A

    1997-11-01

    Quantitative laser fluorescence has been reported as a useful method for the non-destructive in vitro and in vivo diagnosis of early enamel caries. A portable system for intraoral use has been developed with a new light source and filter system replacing the laser light to facilitate clinical application. This new device was validated with microradiographic and chemical analyses for assessment of mineral changes in enamel during lesion formation and remineralization in vitro and compared with the laser light equipment. A significant correlation was found between fluorescence changes and mineral loss: r = 0.79 (laser system) and r = 0.84 (portable lamp system). The correlation between the two fluorescence methods was r = 0.93. The portable fluorescence device seemed to be a promising new tool for reproducible and sensitive assessment of the severity of incipient enamel lesions.

  16. Three-terminal ferroelectric synapse device with concurrent learning function for artificial neural networks

    SciTech Connect

    Nishitani, Y.; Kaneko, Y.; Ueda, M.; Fujii, E.; Morie, T.

    2012-06-15

    Spike-timing-dependent synaptic plasticity (STDP) is demonstrated in a synapse device based on a ferroelectric-gate field-effect transistor (FeFET). STDP is a key of the learning functions observed in human brains, where the synaptic weight changes only depending on the spike timing of the pre- and post-neurons. The FeFET is composed of the stacked oxide materials with ZnO/Pr(Zr,Ti)O{sub 3} (PZT)/SrRuO{sub 3}. In the FeFET, the channel conductance can be altered depending on the density of electrons induced by the polarization of PZT film, which can be controlled by applying the gate voltage in a non-volatile manner. Applying a pulse gate voltage enables the multi-valued modulation of the conductance, which is expected to be caused by a change in PZT polarization. This variation depends on the height and the duration of the pulse gate voltage. Utilizing these characteristics, symmetric and asymmetric STDP learning functions are successfully implemented in the FeFET-based synapse device by applying the non-linear pulse gate voltage generated from a set of two pulses in a sampling circuit, in which the two pulses correspond to the spikes from the pre- and post-neurons. The three-terminal structure of the synapse device enables the concurrent learning, in which the weight update can be performed without canceling signal transmission among neurons, while the neural networks using the previously reported two-terminal synapse devices need to stop signal transmission for learning.

  17. First use of the TandemHeart percutaneous left ventricular assist device as a short-term bridge to cardiac transplantation.

    PubMed

    La Francesca, Saverio; Palanichamy, Nanthini; Kar, Biswajit; Gregoric, Igor D

    2006-01-01

    Advanced heart failure may be refractory despite aggressive support with inotropic agents and intra-aortic balloon pumping. Implantable left ventricular assist devices are increasingly being used as bridges to cardiac transplantation or as destination therapy because of the limited availability of donor organs. We report the 1st use of the TandemHeart percutaneous ventricular assist device as a short-term bridge to cardiac transplantation. PMID:17215977

  18. A Preclinical Study of the Safety and Efficacy of Occlusin Trade-Mark-Sign 500 Artificial Embolization Device in Sheep

    SciTech Connect

    Owen, Richard J.; Nation, Patrick N.; Polakowski, Robert; Biliske, Jennifer A.; Tiege, Paul B.

    2012-06-15

    Introduction: This study evaluated the safety, effectiveness, and biodegradation of a new embolic agent, Occlusin Trade-Mark-Sign 503 Artificial Embolization Device (OCL 503). The agent consists of biodegradable poly-lactic-co-glycolic acid microspheres (150-212 {mu}m) coated with type I bovine collagen and was compared with Embosphere{sup Registered-Sign} Microspheres (300-500 {mu}m) in this controlled study of uterine artery embolization (UAE) in sheep. Methods: Unilateral UAE was performed in 32 adult ewes randomly assigned. Vessels were embolized to effective stasis. The cohort was divided into four groups, which were sacrificed at 1, 3, 6, and 12 months. Results: Both agents were 100% effective in achieving stasis. At 6 months, all OCL 503-treated arteries were occluded, the microspheres degraded with time, and at 12 months all four animals examined demonstrated recanalization. OCL 503 was found in the untreated uterine artery in one animal with no other evidence of non target embolization. In the Embosphere-treated group, all vessels remained occluded and microspheres were detected in the contralateral uterine artery in 6 of 15 examined vessels and in 10 vaginal, 2 ovarian, and 1 vesical artery. No procedural-related complications were seen in either group. Conclusions: OCL 503 is as effective an embolic agent as Embosphere{sup Registered-Sign} Microspheres when embolizing ovine uterine arteries and resorbs with time, allowing recanalization of the treated arteries. No device-related issues or adverse events were observed.

  19. Recent progress in artificial organ research at Tohoku University.

    PubMed

    Yambe, Tomoyuki; Yoshizawa, Makoto; Tanaka, Akira; Abe, Ken-ichi; Kawano, Satoyuki; Matsuki, Hidetoshi; Maruyama, Shigenao; Amae, Shintato; Wada, Naoshi; Kamiyama, Takamichi; Takagi, Toshiyuki; Luo, Run; Hayashi, Junko; Kovalev, Yuri A; X D Sha, Dan; Nanka, Shunsuke; Saijo, Yoshifumi; Mibiki, Yoshiyuki; Shibata, Mune-ichi; Nitta, Shin-ichi

    2003-01-01

    Tohoku University has developed various artificial organs over the last 30 years. Pneumatic driven ventricular assist devices with a silicone ball valve have been designed by the flow visualization method, and clinical trials have been performed in Tohoku University Hospital. On the basis of these developments, a pneumatic driven total artificial heart has been developed and an animal experimental evaluation was conducted. The development of artificial organs in Tohoku University has now progressed to the totally implantable type using the transcutaneous energy transmission system with amorphous fibers for magnetic shielding. Examples of implantable systems include a vibrating flow pump for ventricular assist device, an artificial myocardium by the use of shape memory alloy with Peltier elements, and an artificial sphincter for patients with a stoma. An automatic control system for artificial organs had been developed for the ventricular assist devices including a rotary blood pump to avoid suction and to maintain left and right heart balance. Based upon the technology of automatic control algorithm, a new diagnostic tool for evaluating autonomic nerve function has been developed as a branch of artificial organ research and this new machine has been tested in Tohoku University Hospital. Tohoku University is following a variety of approaches aimed at innovation in artificial organs and medical engineering fields.

  20. Calibration of an instrumented treadmill using a precision-controlled device with artificial neural network-based error corrections.

    PubMed

    Hsieh, Hong-Jung; Lin, Hsiu-Chen; Lu, Hsuan-Lun; Chen, Ting-Yi; Lu, Tung-Wu

    2016-03-01

    Instrumented treadmills (ITs) are used to measure reaction forces (RF) and center of pressure (COP) movements for gait and balance assessment. Regular in situ calibration is essential to ensure their accuracy and to identify conditions when a factory re-calibration is needed. The current study aimed to develop and calibrate in situ an IT using a portable, precision-controlled calibration device with an artificial neural network (ANN)-based correction method. The calibration device was used to apply static and dynamic calibrating loads to the surface of the IT at 189 and 25 grid-points, respectively, at four belt speeds (0, 4, 6 and 8 km/h) without the need of a preset template. Part of the applied and measured RF and COP were used to train a threelayered, back-propagation ANN model while the rest of the data were used to evaluate the performance of the ANN. The percent errors of Fz and errors of the Px and Py were significantly decreased from a maximum of -1.15%, -1.64 mm and -0.73 mm to 0.02%, 0.02 mm and 0.03 mm during static calibration, respectively. During dynamic calibration, the corresponding values were decreasing from -3.65%, 2.58 mm and -4.92 mm to 0.30%, -0.14 mm and -0.47 mm, respectively. The results suggest that the calibration device and associated ANN will be useful for correcting measurement errors in vertical loads and COP for ITs. PMID:26979909

  1. Viscosity-adjusted estimation of pressure head and pump flow with quasi-pulsatile modulation of rotary blood pump for a total artificial heart.

    PubMed

    Yurimoto, Terumi; Hara, Shintaro; Isoyama, Takashi; Saito, Itsuro; Ono, Toshiya; Abe, Yusuke

    2016-09-01

    Estimation of pressure and flow has been an important subject for developing implantable artificial hearts. To realize real-time viscosity-adjusted estimation of pressure head and pump flow for a total artificial heart, we propose the table estimation method with quasi-pulsatile modulation of rotary blood pump in which systolic high flow and diastolic low flow phased are generated. The table estimation method utilizes three kinds of tables: viscosity, pressure and flow tables. Viscosity is estimated from the characteristic that differential value in motor speed between systolic and diastolic phases varies depending on viscosity. Potential of this estimation method was investigated using mock circulation system. Glycerin solution diluted with salty water was used to adjust viscosity of fluid. In verification of this method using continuous flow data, fairly good estimation could be possible when differential pulse width modulation (PWM) value of the motor between systolic and diastolic phases was high. In estimation under quasi-pulsatile condition, inertia correction was provided and fairly good estimation was possible when the differential PWM value was high, which was not different from the verification results using continuous flow data. In the experiment of real-time estimation applying moving average method to the estimated viscosity, fair estimation could be possible when the differential PWM value was high, showing that real-time viscosity-adjusted estimation of pressure head and pump flow would be possible with this novel estimation method when the differential PWM value would be set high.

  2. Prospects for using implanted systems of assisted circulation and artificial heart with a radioisotope power source (biomedical, thermal, and radiation aspects).

    PubMed

    Kiselev, I M; Dubrovskiĭ, G P; Mosidze, T G; Bazhanov, A Iu

    1983-02-01

    The capacity of dogs to diffuse heat (up to 50 W) from an artificial heart and to tolerate prolonged intracorporeal ionizing radiation from a radioisotope power source (238Pu) was investigated, using electrical models of vascular blood heat exchangers that permit reproduction of elimination and heat transmission in autonomous systems. It was shown that up to 50 W can be discharged at temperatures of the wall-blood interface that do not exceed 43 degrees C. Clotting indexes, concentration of total protein, hemolysis, and serum enzyme activity during 1-1.5 months of heating remained within physiologically normal limits. A specific power load of up to 1.5 W/kg at ambient temperatures of 18-20 degrees C revealed no evidence of changes in heat production. By measuring the distribution of power of the dose absorbed around a 45-W plutonium source it was possible to estimate dose loads on critical organs and to assess overall risk of death from malignant tumors induced by radiation over a 10-year period: 6-12% for males and 8-14% for females. It is not very probable that use of the artificial heart with a radioisotope power source will be limited by thermal and radiational effects. PMID:6838399

  3. Viscosity-adjusted estimation of pressure head and pump flow with quasi-pulsatile modulation of rotary blood pump for a total artificial heart.

    PubMed

    Yurimoto, Terumi; Hara, Shintaro; Isoyama, Takashi; Saito, Itsuro; Ono, Toshiya; Abe, Yusuke

    2016-09-01

    Estimation of pressure and flow has been an important subject for developing implantable artificial hearts. To realize real-time viscosity-adjusted estimation of pressure head and pump flow for a total artificial heart, we propose the table estimation method with quasi-pulsatile modulation of rotary blood pump in which systolic high flow and diastolic low flow phased are generated. The table estimation method utilizes three kinds of tables: viscosity, pressure and flow tables. Viscosity is estimated from the characteristic that differential value in motor speed between systolic and diastolic phases varies depending on viscosity. Potential of this estimation method was investigated using mock circulation system. Glycerin solution diluted with salty water was used to adjust viscosity of fluid. In verification of this method using continuous flow data, fairly good estimation could be possible when differential pulse width modulation (PWM) value of the motor between systolic and diastolic phases was high. In estimation under quasi-pulsatile condition, inertia correction was provided and fairly good estimation was possible when the differential PWM value was high, which was not different from the verification results using continuous flow data. In the experiment of real-time estimation applying moving average method to the estimated viscosity, fair estimation could be possible when the differential PWM value was high, showing that real-time viscosity-adjusted estimation of pressure head and pump flow would be possible with this novel estimation method when the differential PWM value would be set high. PMID:27022734

  4. Electromagnetic modelling of current flow in the heart from TASER devices and the risk of cardiac dysrhythmias

    NASA Astrophysics Data System (ADS)

    Holden, S. J.; Sheridan, R. D.; Coffey, T. J.; Scaramuzza, R. A.; Diamantopoulos, P.

    2007-12-01

    Increasing use by law enforcement agencies of the M26 and X26 TASERTASER is an acronym for Thomas A. Swift's Electric Rifle from the book Tom Swift and His Electric Rifle (1911) by Victor Appleton, ISBN-10: 1594561257. electrical incapacitation devices has raised concerns about the arrhythmogenic potential of these weapons. Using a numerical phantom constructed from medical images of the human body in which the material properties of the tissues are represented, computational electromagnetic modelling has been used to predict the currents arising at the heart following injection of M26 and X26 waveforms at the anterior surface of the chest (with one TASER 'barb' directly overlying the ventricles). The modelling indicated that the peak absolute current densities at the ventricles were 0.66 and 0.11 mA mm-2 for the M26 and X26 waveforms, respectively. When applied during the vulnerable period to the ventricular epicardial surface of guinea-pig isolated hearts, the M26 and X26 waveforms induced ectopic beats, but only at current densities greater than 60-fold those predicted by the modelling. When applied to the ventricles in trains designed to mimic the discharge patterns of the TASER devices, neither waveform induced ventricular fibrillation at peak currents >70-fold (for the M26 waveform) and >240-fold (for the X26) higher than the modelled current densities. This study provides evidence for a lack of arrhythmogenic action of the M26 and X26 TASER devices.

  5. Should eligibility for heart transplantation be a requirement for left ventricular assist device use? Recommendations based on a systematic review.

    PubMed

    Boothroyd, Lucy J; Lambert, Laurie J; Sas, Georgeta; Guertin, Jason R; Ducharme, Anique; Charbonneau, Éric; Carrier, Michel; Cecere, Renzo; Morin, Jean E; Bogaty, Peter

    2013-12-01

    Left ventricular assist devices (LVADs) are used in chronic end-stage heart failure as "bridge to transplantation" (BTT) and, more recently, for transplant-ineligible patients as "destination therapy" (DT). We reviewed the evidence on clinical effects and cost-effectiveness of 2 types of continuous-flow LVADs (HeartMate II [HM II] and HeartWare), for BTT and DT patients. We systematically searched the scientific literature (January 2008-June 2012) and identified 14 clinical studies (approximately 2900 HM II and approximately 200 HeartWare patients), and 3 economic evaluations (HM II) using simulation models. Data were, however, limited to 2-3 studies per outcome. We made policy recommendations on the basis of our systematic review. Although complications after implantation are frequent, LVAD therapy is often highly effective across transplantation eligibility status and device, with 1-year survival reaching 86% for BTT and 78% for DT (compared with 25% for medical therapy). Neither BTT nor DT currently meet traditional cost-effectiveness limits in models using historical data, although BTT is standard practice for a limited number of patients in many regions. We found that BTT and DT as implantation strategies tend to be no longer mutually exclusive. We conclude that evidence is sufficient to support LVAD use, regardless of transplantation eligibility status, as long as patients are carefully selected and program infrastructure and budget are adequate. However, evidence gaps, limitations in economic models, and the lack of Canadian data point to the importance of mandatory, systematic monitoring of LVAD use and outcomes. PMID:23978595

  6. Cervical Footprint Anthropometry in Indian Population: Implications on Design of Artificial Disc Replacement Devices

    PubMed Central

    Patil, Vishwanath Mahabaleshwar; Bangalore, Shashidhar Kantharajanna; Saraf, Abhishek

    2016-01-01

    Study Design Cross-sectional study. Purpose To accurately measure the dimensions of cervical endplates based on computed tomography (CT) scans in Indian population and assess accuracy of match with currently available cervical disc prostheses. Overview of Literature The dimensions of currently available cervical disc replacement implants are based on early published geometrical measurements of vertebrae endplates for Caucasian population. To author's knowledge, similar study has not been published for patients from Indian subcontinent. Methods CT scans of cervical spine of patients from Indian subcontinent were collected and reviewed. Seventy patients (54 men and 16 women; aged 18–56 years with average of 37 years) who underwent CT scans of cervical spine were included in study. 3D CT scans of sub axial cervical spine (C3 to C7) were analyzed. The anterior-posterior (AP) and central mediolateral (CML) dimensions of superior and inferior endplates from C3 to C7 were measured using digital measuring system. Results A total of 560 endplates of 70 patients were included in the study. The AP diameter of cervical endplates ranged from 0.87 to 2.47 cm. The CML diameters ranged from 0.84 to 2.98 cm. For levels C3/C4 and C4/C5 for AP dimension Prestige-LP (90.5%) and Prodisc-C (89%) discs showed higher percentage of matching than Discover discs (58.5%). For CML diameter, Prestige-LP (69.5%), Prodisc-C (70%) and Discover (39.5%) discs showed almost similar matching with measured endplates. For levels C5/C6 and C6/C7 for AP dimension, Prestige-LP (67.25%), Prodisc-C (49.35%) and Discover (51.5%) discs showed similar matching. For CML diameter Prestige-LP (32%), Prodisc-C (27.5%) and Discover (42.2%) discs showed poor matching with measured endplates. Conclusions This study indicates need for redesign of cervical disc prostheses to match Indian patients. The collected anthropometric dimensions from this study may be used to design and develop indigenous artificial total disc

  7. Past and present of cardiocirculatory assist devices: a comprehensive critical review

    PubMed Central

    Rigatelli, Gianluca; Santini, Francesco; Faggian, Giuseppe

    2012-01-01

    During the last 20 years, the management of heart failure has significantly improved by means of new pharmacotherapies, more timely invasive treatments and device assisted therapies. Indeed, advances in mechanical support, namely with the development of more efficient left ventricular assist devices (LVADs), and the total artificial heart have reduced mortality and morbidity in patients awaiting transplantation, so much so, that LVADs are now approved of as a strategy for destination therapy. In this review, the authors describe in detail the current basic indications, functioning modalities, main limitations of surgical LAVDs, total artificial heart development, and percutaneous assist devices, trying to clarify this complex, but fascinating topic. PMID:23341844

  8. Perventricular device closure of residual muscular ventricular septal defects after repair of complex congenital heart defects in pediatric patients.

    PubMed

    Zhu, Da; Tao, Kaiyu; An, Qi; Luo, Shuhua; Gan, Changping; Lin, Ke

    2013-01-01

    Residual muscular ventricular septal defects are surgical challenges, especially after the repair of complex congenital heart defects. We investigated perventricular device closure as a salvage technique in pediatric patients who had postoperative residual muscular ventricular septal defects. From February 2009 through June 2011, 14 pediatric patients at our hospital had residual muscular ventricular septal defects after undergoing surgical repair of complex congenital heart defects. Ten patients met our criteria for perventricular device closure of the residual defects: significant left-to-right shunting (Qp/Qs >1.5) or substantial hemodynamic instability (a defect ≥2 mm in size). The patients' mean age was 20.4 ± 13.5 months, and their mean body weight was 10 ± 3.1 kg. The median diameter of the residual defects was 4.2 mm (range, 2.5-5.1 mm). We deployed a total of 11 SQFDQ-II Muscular VSD Occluders (Shanghai Shape Memory Alloy Co., Ltd.; Shanghai, China) in the 10 patients, in accord with conventional techniques of perventricular device closure. The mean procedural duration was 31.1 ±9.1 min. We recorded the closure and complication rates perioperatively and during a 12-month follow-up period. Complete closure was achieved in 8 patients; 2 patients had persistent trivial residual shunts. No deaths, conduction block, device embolism, or other complications occurred throughout the study period. We conclude that perventricular device closure is a safe, effective salvage treatment for postoperative residual muscular ventricular septal defects in pediatric patients. Long-term studies with larger cohorts might further confirm this method's feasibility.

  9. Concurrent Left Ventricular Assist Device (LVAD) Implantation and Percutaneous Temporary RVAD Support via CardiacAssist Protek-Duo TandemHeart to Preempt Right Heart Failure

    PubMed Central

    Schmack, Bastian; Weymann, Alexander; Popov, Aron-Frederik; Patil, Nikhil Prakash; Sabashnikov, Anton; Kremer, Jamila; Farag, Mina; Brcic, Andreas; Lichtenstern, Christoph; Karck, Matthias; Ruhparwar, Arjang

    2016-01-01

    Right ventricular failure (RVF) is an unfortunate complication that continues to limit outcomes following durable left ventricular assist device (LVAD) implantation. Despite several ‘RVF risk scores’ having been proposed, preoperative prediction of post-LVAD RVF remains a guesstimate at best. Current strategies for institution of temporary RVAD support are invasive, necessitate additional re-thoracotomy, restrict postoperative mobilization, and/or entail prolonged retention of prosthetic material in-situ. The authors propose a novel surgical strategy comprising simultaneous implantation of a permanent LVAD and percutaneous TandemHeart® plus ProtekDuo® to provide temporary RVAD support and preempt RVF in patients with impaired RV function. PMID:27145697

  10. Are Currently Available Wearable Devices for Activity Tracking and Heart Rate Monitoring Accurate, Precise, and Medically Beneficial?

    PubMed Central

    El-Amrawy, Fatema

    2015-01-01

    Objectives The new wave of wireless technologies, fitness trackers, and body sensor devices can have great impact on healthcare systems and the quality of life. However, there have not been enough studies to prove the accuracy and precision of these trackers. The objective of this study was to evaluate the accuracy, precision, and overall performance of seventeen wearable devices currently available compared with direct observation of step counts and heart rate monitoring. Methods Each participant in this study used three accelerometers at a time, running the three corresponding applications of each tracker on an Android or iOS device simultaneously. Each participant was instructed to walk 200, 500, and 1,000 steps. Each set was repeated 40 times. Data was recorded after each trial, and the mean step count, standard deviation, accuracy, and precision were estimated for each tracker. Heart rate was measured by all trackers (if applicable), which support heart rate monitoring, and compared to a positive control, the Onyx Vantage 9590 professional clinical pulse oximeter. Results The accuracy of the tested products ranged between 79.8% and 99.1%, while the coefficient of variation (precision) ranged between 4% and 17.5%. MisFit Shine showed the highest accuracy and precision (along with Qualcomm Toq), while Samsung Gear 2 showed the lowest accuracy, and Jawbone UP showed the lowest precision. However, Xiaomi Mi band showed the best package compared to its price. Conclusions The accuracy and precision of the selected fitness trackers are reasonable and can indicate the average level of activity and thus average energy expenditure. PMID:26618039

  11. Thoratec HeartMate II(®) left ventricular assist device implantation in patient with patent ventriculoperitoneal shunt.

    PubMed

    Yamane, Kentaro; Bogar, Linda J; Tabata, Shigeki; Hirose, Hitoshi

    2012-01-01

    We report a case of HeartMate II(®) left ventricular assist device (LVAD) implantation as a destination therapy in a patient with a patent ventriculoperitoneal (VP) shunt after being suffered from subarachnoid hemorrhage. Because the patient's VP shunt was running through her right anterior chest and abdominal wall, a driveline exit site was selected in her left upper quadrant to avoid unnecessary perioperative complication in relation to the patent VP shunt tube. Tailored driveline placement was a key element of this LVAD implantation in this already sick patient with multiple comorbidities.

  12. Timing of temporary right ventricular assist device insertion for severe right heart failure after left ventricular assist device implantation.

    PubMed

    Takeda, Koji; Naka, Yoshifumi; Yang, Jonathan A; Uriel, Nir; Colombo, Paolo C; Jorde, Ulrich P; Takayama, Hiroo

    2013-01-01

    Data on how the timing of a temporary right ventricular assist device (RVAD) insertion affects outcome are limited in patients receiving left ventricular assist device (LVAD). Of the 282 patients who underwent LVAD placement between January 2000 and November 2010, 40 (14%) required concomitant (n = 26) or delayed (n = 14) RVAD insertion as temporary support. We analyzed early and 1-year outcomes. Preoperative variables were similar in the concomitant and delayed RVAD groups. The hospital mortality rate was approximately 50% in both groups (p = 0.82). The 1-year actuarial survival was similar in both groups (p = 0.42). Patients who required RVAD support had higher in-hospital mortality and worse 1-year survival rates than those who received LVAD only (48% vs. 9.5%, p < 0.0001; 40% vs. 82%, p < 0.0001). Multivariate logistic regression analysis indicated RVAD use as a significant risk factor for 1-year mortality (odds ratio, 18; p = 0.0003; 95% confidence interval, 3.765-86.74). Timing of temporary RVAD insertion did not affect overall survival. Necessity of RVAD support is associated with significantly worse early and late mortality at any rate. The decision to place the RVAD can be made once it is clinically necessary.

  13. The use of artificial neural networks for optimizing polydispersity index (PDI) in nanoprecipitation process of acetaminophen in microfluidic devices.

    PubMed

    Aghajani, Mahdi; Shahverdi, Ahmad Reza; Amani, Amir

    2012-12-01

    Artificial neural networks (ANNs) were used in this study to determine factors that control the polydispersity index (PDI) in an acetaminophen nanosuspension which was prepared using nanoprecipitation in microfluidic devices. The PDI of prepared formulations was measured by dynamic light scattering. Afterwards, the ANNs were applied to model the data. Four independent variables, namely, surfactant concentration, solvent temperature, and flow rate of solvent and antisolvent were considered as input variables, and the PDI of acetaminophen nanosuspension was taken as the output variable. The response surfaces, generated as 3D graphs after modeling, were used to survey the interactions happening between the input variables and the output variable. Comparison of the response surfaces indicated that the antisolvent flow rate and the solvent temperature have reverse effect on the PDI, whereas solvent flow rate has direct relation with PDI. Also, the effect of the concentration of the surfactant on the PDI was found to be indirect and less influential. Overall, it was found that minimum PDI may be obtained at high values of antisolvent flow rate and solvent temperature, while the solvent flow rate should be kept to a minimum.

  14. Symbolic Dynamics Analysis of Short Data Sets: an Application to Heart Rate Variability from Implantable Defibrillator Devices

    NASA Astrophysics Data System (ADS)

    Zebrowski, Jan J.; Baranowski, Rafal; Przybylski, Andrzej

    2003-07-01

    A method is described for the assessment of the complexity of short data sets by nonlinear dynamics. The method was devised for and tested on human heart rate recordings approximately 2000 to 9000 RR intervals long which were extracted from the memory of implantable defibrillator devices (ICD). It is, however, applicable in a more general context. The ICDs are meant to control life-threatening episodes of ventricular tachycardia and/or ventricular fibrillation by applying a electric shock to the heart through intracardiac electrodes. It is well known that conventional ICD algorithms yield approximately 20--30 % of spurious interventions. The main aim of this work is to look for nonlinear dynamics methods to enhance the appropriateness of the ICD intervention. We first showed that nonlinear dynamics methods first applied to 24-hour heart rate variability analysis were able to detect the need for the ICD intervention. To be applicable to future ICD use, the methods must also be low in computational requirements. Methods to analyse the complexity of the short and non-stationary sets were devised. We calculated the Shannon entropy of symbolic words obtained in a sliding 50 beat window and analysed the dependence of this complexity measure on the time. Precursors were found extending much earlier time than the time the standard ICD algorithms span.

  15. Ventricular assist device

    MedlinePlus

    VAD; RVAD; LVAD; BVAD; Right ventricular assist device; Left ventricular assist device; Biventricular assist device; Heart pump; Left ventricular assist system; LVAS; Implantable ventricular assist device

  16. [Design of a Front-end Device of Heart Rate Variability Analysis System Based on Photoplethysmography].

    PubMed

    Shi, Lei; Sun, Peng; Pang, Yu; Luo, Zhiyong; Wang, Wei; Wang, Yanxiang

    2016-02-01

    Heart rate variability (HRV) is the difference between the successive changes in the heartbeat cycle, and it is produced in the autonomic nervous system modulation of the sinus node of the heart. The HRV is a valuable indicator in predicting the sudden cardiac death and arrhythmic events. Traditional analysis of HRV is based on a multielectrocardiogram (ECG), but the ECG signal acquisition is complex, so we have designed an HRV analysis system based on photoplethysmography (PPG). PPG signal is collected by a microcontroller from human's finger, and it is sent to the terminal via USB-Serial module. The terminal software not only collects the data and plot waveforms, but also stores the data for future HRV analysis. The system is small in size, low in power consumption, and easy for operation. It is suitable for daily care no matter whether it is used at home or in a hospital. PMID:27382733

  17. Design a Wearable Device for Blood Oxygen Concentration and Temporal Heart Beat Rate

    NASA Astrophysics Data System (ADS)

    Myint, Cho Zin; Barsoum, Nader; Ing, Wong Kiing

    2010-06-01

    The wireless network technology is increasingly important in healthcare as a result of the aging population and the tendency to acquire chronic disease such as heart attack, high blood pressure amongst the elderly. A wireless sensor network system that has the capability to monitor physiological sign such as SpO2 (Saturation of Arterial Oxygen) and heart beat rate in real-time from the human's body is highlighted in this study. This research is to design a prototype sensor network hardware, which consists of microcontroller PIC18F series and transceiver unit. The sensor is corporate into a wearable body sensor network which is small in size and easy to use. The sensor allows a non invasive, real time method to provide information regarding the health of the body. This enables a more efficient and economical means for managing the health care of the population.

  18. [(Bio)artificial liver support: ready for the patient?].

    PubMed

    Chamuleau, R A F M

    2016-05-01

    In 2016, an intensive-care physician has at his disposal a number of artificial organs for the support of patients with organ failure. Examples are the artificial kidney and the heart-lung machine. Artificial livers are being developed for patients with severe liver failure whose lives can only be saved at the present time by a transplant with a donor liver. These artificial livers are based either on a device that removes toxic materials from the patient's blood with, for example, albumin dialysis, or make use of bio-reactors filled with functioning liver cells, the so-called bio-artificial liver. In theory, the bio-artificial liver has the greatest potential to increase life expectancy. The results of clinical studies are also very promising. They are not yet sufficient, however, to permit general clinical use.

  19. [(Bio)artificial liver support: ready for the patient?].

    PubMed

    Chamuleau, R A F M

    2016-05-01

    In 2016, an intensive-care physician has at his disposal a number of artificial organs for the support of patients with organ failure. Examples are the artificial kidney and the heart-lung machine. Artificial livers are being developed for patients with severe liver failure whose lives can only be saved at the present time by a transplant with a donor liver. These artificial livers are based either on a device that removes toxic materials from the patient's blood with, for example, albumin dialysis, or make use of bio-reactors filled with functioning liver cells, the so-called bio-artificial liver. In theory, the bio-artificial liver has the greatest potential to increase life expectancy. The results of clinical studies are also very promising. They are not yet sufficient, however, to permit general clinical use. PMID:27166453

  20. A new approach to heart valve tissue engineering: mimicking the heart ventricle with a ventricular assist device in a novel bioreactor.

    PubMed

    Kaasi, Andreas; Cestari, Idágene A; Stolf, Noedir A G; Leirner, Adolfo A; Hassager, Ole; Cestari, Ismar N

    2011-04-01

    The 'biomimetic' approach to tissue engineering usually involves the use of a bioreactor mimicking physiological parameters whilst supplying nutrients to the developing tissue. Here we present a new heart valve bioreactor, having as its centrepiece a ventricular assist device (VAD), which exposes the cell-scaffold constructs to a wider array of mechanical forces. The pump of the VAD has two chambers: a blood and a pneumatic chamber, separated by an elastic membrane. Pulsatile air-pressure is generated by a piston-type actuator and delivered to the pneumatic chamber, ejecting the fluid in the blood chamber. Subsequently, applied vacuum to the pneumatic chamber causes the blood chamber to fill. A mechanical heart valve was placed in the VAD's inflow position. The tissue engineered (TE) valve was placed in the outflow position. The VAD was coupled in series with a Windkessel compliance chamber, variable throttle and reservoir, connected by silicone tubings. The reservoir sat on an elevated platform, allowing adjustment of ventricular preload between 0 and 11 mmHg. To allow for sterile gaseous exchange between the circuit interior and exterior, a 0.2 µm filter was placed at the reservoir. Pressure and flow were registered downstream of the TE valve. The circuit was filled with culture medium and fitted in a standard 5% CO(2) incubator set at 37 °C. Pressure and flow waveforms were similar to those obtained under physiological conditions for the pulmonary circulation. The 'cardiomimetic' approach presented here represents a new perspective to conventional biomimetic approaches in TE, with potential advantages. PMID:20687125

  1. Utility of a Novel Biofeedback Device for Within-Breath Modulation of Heart Rate in Rats: A Quantitative Comparison of Vagus Nerve vs. Right Atrial Pacing.

    PubMed

    O'Callaghan, Erin L; Chauhan, Ashok S; Zhao, Le; Lataro, Renata M; Salgado, Helio C; Nogaret, Alain; Paton, Julian F R

    2016-01-01

    In an emerging bioelectronics era, there is a clinical need for physiological devices incorporating biofeedback that permits natural and demand-dependent control in real time. Here, we describe a novel device termed a central pattern generator (CPG) that uses cutting edge analog circuitry producing temporally controlled, electrical stimulus outputs based on the real time integration of physiological feedback. Motivated by the fact that respiratory sinus arrhythmia (RSA), which is the cyclical changes in heart rate every breath, is an essential component of heart rate variability (HRV) (an indicator of cardiac health), we have explored the versatility and efficiency of the CPG for producing respiratory modulation of heart rate in anesthetized, spontaneously breathing rats. Diaphragmatic electromyographic activity was used as the input to the device and its output connected to either the right cervical vagus nerve or the right atrium for pacing heart rate. We found that the CPG could induce respiratory related heart rate modulation that closely mimicked RSA. Whether connected to the vagus nerve or right atrium, the versatility of the device was demonstrated by permitting: (i) heart rate modulation in any phase of the respiratory cycle, (ii) control of the magnitude of heart rate modulation, and (iii) instant adaptation to changes in respiratory frequency. Vagal nerve pacing was only possible following transection of the nerve limiting its effective use chronically. Pacing via the right atrium permitted better flexibility and control of heart rate above its intrinsic level. This investigation now lays the foundation for future studies using this biofeedback technology permitting closer analysis of both the function and dysfunction of RSA. PMID:26869940

  2. Utility of a Novel Biofeedback Device for Within-Breath Modulation of Heart Rate in Rats: A Quantitative Comparison of Vagus Nerve vs. Right Atrial Pacing

    PubMed Central

    O'Callaghan, Erin L.; Chauhan, Ashok S.; Zhao, Le; Lataro, Renata M.; Salgado, Helio C.; Nogaret, Alain; Paton, Julian F. R.

    2016-01-01

    In an emerging bioelectronics era, there is a clinical need for physiological devices incorporating biofeedback that permits natural and demand-dependent control in real time. Here, we describe a novel device termed a central pattern generator (CPG) that uses cutting edge analog circuitry producing temporally controlled, electrical stimulus outputs based on the real time integration of physiological feedback. Motivated by the fact that respiratory sinus arrhythmia (RSA), which is the cyclical changes in heart rate every breath, is an essential component of heart rate variability (HRV) (an indicator of cardiac health), we have explored the versatility and efficiency of the CPG for producing respiratory modulation of heart rate in anesthetized, spontaneously breathing rats. Diaphragmatic electromyographic activity was used as the input to the device and its output connected to either the right cervical vagus nerve or the right atrium for pacing heart rate. We found that the CPG could induce respiratory related heart rate modulation that closely mimicked RSA. Whether connected to the vagus nerve or right atrium, the versatility of the device was demonstrated by permitting: (i) heart rate modulation in any phase of the respiratory cycle, (ii) control of the magnitude of heart rate modulation, and (iii) instant adaptation to changes in respiratory frequency. Vagal nerve pacing was only possible following transection of the nerve limiting its effective use chronically. Pacing via the right atrium permitted better flexibility and control of heart rate above its intrinsic level. This investigation now lays the foundation for future studies using this biofeedback technology permitting closer analysis of both the function and dysfunction of RSA. PMID:26869940

  3. Utility of a Novel Biofeedback Device for Within-Breath Modulation of Heart Rate in Rats: A Quantitative Comparison of Vagus Nerve vs. Right Atrial Pacing.

    PubMed

    O'Callaghan, Erin L; Chauhan, Ashok S; Zhao, Le; Lataro, Renata M; Salgado, Helio C; Nogaret, Alain; Paton, Julian F R

    2016-01-01

    In an emerging bioelectronics era, there is a clinical need for physiological devices incorporating biofeedback that permits natural and demand-dependent control in real time. Here, we describe a novel device termed a central pattern generator (CPG) that uses cutting edge analog circuitry producing temporally controlled, electrical stimulus outputs based on the real time integration of physiological feedback. Motivated by the fact that respiratory sinus arrhythmia (RSA), which is the cyclical changes in heart rate every breath, is an essential component of heart rate variability (HRV) (an indicator of cardiac health), we have explored the versatility and efficiency of the CPG for producing respiratory modulation of heart rate in anesthetized, spontaneously breathing rats. Diaphragmatic electromyographic activity was used as the input to the device and its output connected to either the right cervical vagus nerve or the right atrium for pacing heart rate. We found that the CPG could induce respiratory related heart rate modulation that closely mimicked RSA. Whether connected to the vagus nerve or right atrium, the versatility of the device was demonstrated by permitting: (i) heart rate modulation in any phase of the respiratory cycle, (ii) control of the magnitude of heart rate modulation, and (iii) instant adaptation to changes in respiratory frequency. Vagal nerve pacing was only possible following transection of the nerve limiting its effective use chronically. Pacing via the right atrium permitted better flexibility and control of heart rate above its intrinsic level. This investigation now lays the foundation for future studies using this biofeedback technology permitting closer analysis of both the function and dysfunction of RSA.

  4. A novel device based on smart textile to control heart's activity during exercise.

    PubMed

    Romagnoli, Marco; Alis, Rafael; Guillen, Javier; Basterra, Javier; Villacastin, J P; Guillen, Sergio

    2014-06-01

    In recent years, several systems have been developed to control cardiac function during exercise, and some are also capable of recording RR data to provide heart rate variability (HRV) analyses. In this study we compare time between heart beats and HRV parameters obtained with a smart textile system (GOW; Weartech sl., Spain) and an electrocardiogram machine commonly used in hospitals during continuous cycling tests. Twelve cardiology patients performed a 30-min cycling test at stable submaximal intensity. RR interval data were recorded during the test by both systems. 3-min RR segments were taken to compare the time intervals between beats and HRV variables using Bland-Altman analyses and intraclass correlation coefficients. Limits of agreement (LoAs) on RR intervals were stable at around 3 ms (widest LoAs -5.754 to 6.094 ms, tightest LoAs -2.557 to 3.105 ms, medium LoAs -3.638 ± 0.812 to 3.145 ± 0.539 ms). HRV parameters related to short-term change presented wide LoAs (RMSSD -0.17 to 18.41 %, HF -17.64 to 33.21 %, SD1 -0.50 to 17.54 %) as an effect of the error measurement of the GOW system. The GOW system is a valid tool for controlling HR during physical activity, although its use as a clinical tool for HRV cannot be supported.

  5. A novel device based on smart textile to control heart's activity during exercise.

    PubMed

    Romagnoli, Marco; Alis, Rafael; Guillen, Javier; Basterra, Javier; Villacastin, J P; Guillen, Sergio

    2014-06-01

    In recent years, several systems have been developed to control cardiac function during exercise, and some are also capable of recording RR data to provide heart rate variability (HRV) analyses. In this study we compare time between heart beats and HRV parameters obtained with a smart textile system (GOW; Weartech sl., Spain) and an electrocardiogram machine commonly used in hospitals during continuous cycling tests. Twelve cardiology patients performed a 30-min cycling test at stable submaximal intensity. RR interval data were recorded during the test by both systems. 3-min RR segments were taken to compare the time intervals between beats and HRV variables using Bland-Altman analyses and intraclass correlation coefficients. Limits of agreement (LoAs) on RR intervals were stable at around 3 ms (widest LoAs -5.754 to 6.094 ms, tightest LoAs -2.557 to 3.105 ms, medium LoAs -3.638 ± 0.812 to 3.145 ± 0.539 ms). HRV parameters related to short-term change presented wide LoAs (RMSSD -0.17 to 18.41 %, HF -17.64 to 33.21 %, SD1 -0.50 to 17.54 %) as an effect of the error measurement of the GOW system. The GOW system is a valid tool for controlling HR during physical activity, although its use as a clinical tool for HRV cannot be supported. PMID:24756693

  6. [Analysis of the causes of potential wear and breakdown of elements of artificial heart valves of the disk type].

    PubMed

    Dobrova, N B; Iofis, N A; Kozyrkin, B I; Agafonov, A V; Zaretskiĭ, Iu V

    1987-01-01

    The reliability analysis of the artificial cardiac valve and experiments made it possible to establish that the ACV reliability is ensured by the physical and mechanical properties of the material, technology observance and thorough control over each operation during the manufacturing process. The accelerated testing of the new MX disk valve made in the USSR showed a satisfactory degree of the disk wear and the absence of breaks-down after 400 million working cycles which is equivalent to ten-years' work in a human body.

  7. Replacement of implantable cardioverter defibrillators and cardiac resynchronization therapy devices: results of the European Heart Rhythm Association survey.

    PubMed

    Tilz, Roland; Boveda, Serge; Deharo, Jean-Claude; Dobreanu, Dan; Haugaa, Kristina H; Dagres, Nikolaos

    2016-06-01

    The aim of this EP Wire was to assess the management, indications, and techniques for implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy (CRT) device replacement in Europe. A total of 24 centres in 14 European countries completed the questionnaire. All centres were members of the European Heart Rhythm Association Electrophysiology Research Network. Replacement procedures were performed by electrophysiologists in 52% of the centres, by cardiologists in 33%, and both in the remaining centres. In the majority of centres, the procedures were performed during a short hospitalization (<2 days; 61.2%), or on an outpatient basis (28%). The overwhelming majority of centres reported that they replaced ICDs at the end of battery life. Only in a small subset (<10%) of patients with ICD for primary prevention and without ventricular tachycardia (VT) since implantation, ICD was not replaced. In inherited primary arrhythmia syndromes, 80% of the centres always replaced the ICD at the end of battery life. After VT ablation, only few centres (9%) explanted or downgraded the device that was previously implanted for secondary prevention, but only in those patients without new VT episodes. Patient's life expectancy <1 year was the most commonly reported reason (61%) to downgrade from a CRT-D to a CRT-P device. While warfarin therapy was continued in 47% of the centres, non-vitamin K oral anticoagulants were discontinued without bridging 24 h prior to replacement procedures in 60%. Finally, in 65% of the centres, VT induction and shock testing during ICD and CRT-D replacement were performed only in the case of leads with a warning or with borderline measurements. This survey provides a snapshot of the perioperative management, indications, and techniques of ICD and CRT device replacement in Europe. It demonstrates some variations between participating centres, probably related to local policies and to the heterogeneity of the ICD population. PMID

  8. Preferred tools and techniques for implantation of cardiac electronic devices in Europe: results of the European Heart Rhythm Association survey.

    PubMed

    Bongiorni, Maria Grazia; Proclemer, Alessandro; Dobreanu, Dan; Marinskis, Germanas; Pison, Laurent; Blomstrom-Lundqvist, Carina

    2013-11-01

    The aim of this European Heart Rhythm Association (EHRA) survey was to assess clinical practice in relation to the tools and techniques used for cardiac implantable electronic devices procedures in the European countries. Responses to the questionnaire were received from 62 members of the EHRA research network. The survey involved high-, medium-, and low-volume implanting centres, performing, respectively, more than 200, 100-199 and under 100 implants per year. The following topics were explored: the side approach for implantation, surgical techniques for pocket incision, first venous access for lead implantation, preference of lead fixation, preferred coil number for implantable cardioverter-defibrillator (ICD) leads, right ventricular pacing site, generator placement site, subcutaneous ICD implantation, specific tools and techniques for cardiac resynchronization therapy (CRT), lead implantation sequence in CRT, coronary sinus cannulation technique, target site for left ventricular lead placement, strategy in left ventricular lead implant failure, mean CRT implantation time, optimization of the atrioventricular (AV) and ventriculo-ventricular intervals, CRT implants in patients with permanent atrial fibrillation, AV node ablation in patients with permanent AF. This panoramic view allows us to find out the operator preferences regarding the techniques and tools for device implantation in Europe. The results showed different practices in all the fields we investigated, nevertheless the survey also outlines a good adherence to the common standards and recommendations.

  9. Replacement of a malfunctioning HeartMate II left ventricular assist device in a 14-year-old after a sudden fall.

    PubMed

    La Francesca, Saverio; Smith, Ron; Gregoric, Igor D; Kar, Biswajit; Myers, Timothy J; Price, Jack; Kennedy, Damon; Frazier, O H

    2006-07-01

    An increasing number of patients are returning to normal activity after implantation of intracorporeal left ventricular assist devices. We describe the emergency replacement of the impeller portion of a HeartMate II left ventricular assist system that had stopped functioning after the 14-year-old recipient experienced a sudden fall from a skateboard.

  10. Intelligent Li ion battery management based on a digital signal processor for a moving actuator total artificial heart.

    PubMed

    Kim, W E; Ahn, J M; Choi, S W; Min, B G

    1997-01-01

    An intelligent Li Ion battery management (ILBM) system was developed based on a digital signal processor (DSP). Instead of using relatively complicated hardware charging control, a DSP algorithm was used, and favorable characteristics in volume, mass, and temperature increase of the implantable battery were achieved. In vitro tests were performed to evaluate the DSP based algorithm for Li Ion charging control (24 V dc motor input power 16 W, 5 L/min, 100 mmHg afterload). In this article, the first improvement was volume reduction using a Li Ion battery (3.6 V/Cell, 900 mA, seven cells: 25.2 V, 22.7 W). Its volume and mass were decreased by 40% and 50% respectively (40*55*75 mm, 189 g), compared to previously reported results, with total energy capacity increased by 110% (more than 60 min vs 25 min run time in the other battery). The second improvement includes the ILBM, which can control the performance detection for each unit cell and has a low temperature rise. The ILBM's unit cell energy detection was important because the low performance of one cell dropped to 50% of the total performance along with a 20% increase in surface temperature. All electronics for a transcutaneous energy transmission (TET), battery, and telemetry were finalized for hybridization and used for total artificial heat (TAH) implantation.

  11. Ramp Study Hemodynamics, Functional Capacity, and Outcome in Heart Failure Patients with Continuous-Flow Left Ventricular Assist Devices.

    PubMed

    Jung, Mette H; Gustafsson, Finn; Houston, Brian; Russell, Stuart D

    2016-01-01

    Ramp studies-measuring changes in cardiac parameters as a function of serial pump speed changes (revolutions per minute [rpm])-are increasingly used to evaluate function and malfunction of continuous-flow left ventricular assist devices (CF-LVADs). We hypothesized that ramp studies can predict functional capacity, quality of life (QOL), and survival in CF-LVAD patients. Hemodynamic changes per Δrpm were measured at a minimum of CF-LVAD support, at baseline pump speed, and at maximal tolerable pump speed. Subsequently functional capacity and QOL were assessed. Eighty ramp tests were performed in 44 patients (HeartMate II, Thoratec Corporation, Pleasanton, CA). Functional status was evaluated in 70% (31/44); average 6 minute walk test (6MWT) was 312 ± 220 min, New York Heart Association (NYHA) I-II/III-IV (70/30%) and activity scores very low-low/moderate-very high (55/45%). Decrease in pulmonary capillary wedge pressure per Δrpm was related to better NYHA classification; NYHA I-II vs. III-IV, -0.29 ± 0.15 vs. -0.09 ± 0.16 mm Hg/rpm * 10 (p = 0.007) as well as to activity score; very low-low vs. moderate-very high, -0.16 ± 0.16 vs. -0.31 ± 0.16 mm Hg/rpm * 10 (p = 0.02). Cardiac output change per Δrpm was correlated to measures of QOL. Ramp tests did not predict survival. In conclusion, hemodynamic changes during ramp studies are associated with measures of functional capacity and QOL. Hence, such tests could potentially identify patients in risk of failure to thrive during CF-LVAD support.

  12. Ramp Study Hemodynamics, Functional Capacity, and Outcome in Heart Failure Patients with Continuous-Flow Left Ventricular Assist Devices.

    PubMed

    Jung, Mette H; Gustafsson, Finn; Houston, Brian; Russell, Stuart D

    2016-01-01

    Ramp studies-measuring changes in cardiac parameters as a function of serial pump speed changes (revolutions per minute [rpm])-are increasingly used to evaluate function and malfunction of continuous-flow left ventricular assist devices (CF-LVADs). We hypothesized that ramp studies can predict functional capacity, quality of life (QOL), and survival in CF-LVAD patients. Hemodynamic changes per Δrpm were measured at a minimum of CF-LVAD support, at baseline pump speed, and at maximal tolerable pump speed. Subsequently functional capacity and QOL were assessed. Eighty ramp tests were performed in 44 patients (HeartMate II, Thoratec Corporation, Pleasanton, CA). Functional status was evaluated in 70% (31/44); average 6 minute walk test (6MWT) was 312 ± 220 min, New York Heart Association (NYHA) I-II/III-IV (70/30%) and activity scores very low-low/moderate-very high (55/45%). Decrease in pulmonary capillary wedge pressure per Δrpm was related to better NYHA classification; NYHA I-II vs. III-IV, -0.29 ± 0.15 vs. -0.09 ± 0.16 mm Hg/rpm * 10 (p = 0.007) as well as to activity score; very low-low vs. moderate-very high, -0.16 ± 0.16 vs. -0.31 ± 0.16 mm Hg/rpm * 10 (p = 0.02). Cardiac output change per Δrpm was correlated to measures of QOL. Ramp tests did not predict survival. In conclusion, hemodynamic changes during ramp studies are associated with measures of functional capacity and QOL. Hence, such tests could potentially identify patients in risk of failure to thrive during CF-LVAD support. PMID:27195741

  13. [Evaluation of heart impact in the 100 m extreme intensity sport using near-infrared non-invasive muscle oxygen detecting device and sports heart rate detection technology].

    PubMed

    Wang, Pei-Yong; Long, Fei-Xiao; Fu, Lan-Ying; Li, Yue; Ding, Hai-Shu; Qu, An-Lian; Zhou, Xiao-Ping

    2010-02-01

    Using continuous two wavelength near-infrared technology to detect the variation in the consistency of oxygen hemoglobin in the muscle and the sports heart rate wireless real time collection technology, we devised the real time muscle tissue oxygenation and instantaneous heart rate experiment scheme and implemented it for the process of the 100 m run with two parameters given simultaneously. The experiment shows that the concentration of the oxygen hemoglobin in the muscle tissue continues decreasing after the end of the 100 m run, and the time interval between the moment when the concentration of the oxygen hemoglobin attains the minimum value and the moment when the athletes finish the 100 m run is (6.65 +/- 1.10) sec; while the heart rate continues increasing after the end of the 100 m run, and the time interval between the moment when the heart rate attains the maximum value and the moment when the athletes finish the 100 m run is (8.00 +/- 1.57) sec. The results show that the two wavelength near-infrared tissue oxygenation detection technology and the sports heart rate real time collection equipment can accurately measure the sports tissue oxygenation and the heart rate in the extreme intensity sport, and reveal the process of muscle oxygen transportation and consumption and its dynamic character with the heart rate in the extreme intensity sport.

  14. Artificial muscle: facts and fiction.

    PubMed

    Schaub, Marcus C

    2011-01-01

    Mechanical devices are sought to support insufficient or paralysed striated muscles including the failing heart. Nickel-titanium alloys (nitinol) present the following two properties: (i) super-elasticity, and (ii) the potential to assume different crystal structures depending on temperature and/or stress. Starting from the martensite state nitinol is able to resume the austenite form (state of low potential energy and high entropy) even against an external resistance. This one-way shape change is deployed in self-expanding vascular stents. Heating induces the force generating transformation from martensite to the austenite state while cooling induces relaxation back to the martensite state. This two-way shape change oscillating between the two states may be used in cyclically contracting support devices of silicon-coated nitinol wires. Such a contractile device sutured to the right atrium has been tested in vitro in a bench model and in vivo in sheep. The contraction properties of natural muscles, specifically of the myocardium, and the tight correlation with ATP production by oxidative phosphorylation in the mitochondria is briefly outlined. Force development by the nitinol device cannot be smoothly regulated as in natural muscle. Its mechanical impact is forced onto the natural muscle regardless of the actual condition with regard to metabolism and Ca2+-homeostasis. The development of artificial muscle on the basis of nitinol wires is still in its infancy. The nitinol artificial muscle will have to prove its viability in the various clinical settings. PMID:22183715

  15. Artificial muscle: facts and fiction.

    PubMed

    Schaub, Marcus C

    2011-12-19

    Mechanical devices are sought to support insufficient or paralysed striated muscles including the failing heart. Nickel-titanium alloys (nitinol) present the following two properties: (i) super-elasticity, and (ii) the potential to assume different crystal structures depending on temperature and/or stress. Starting from the martensite state nitinol is able to resume the austenite form (state of low potential energy and high entropy) even against an external resistance. This one-way shape change is deployed in self-expanding vascular stents. Heating induces the force generating transformation from martensite to the austenite state while cooling induces relaxation back to the martensite state. This two-way shape change oscillating between the two states may be used in cyclically contracting support devices of silicon-coated nitinol wires. Such a contractile device sutured to the right atrium has been tested in vitro in a bench model and in vivo in sheep. The contraction properties of natural muscles, specifically of the myocardium, and the tight correlation with ATP production by oxidative phosphorylation in the mitochondria is briefly outlined. Force development by the nitinol device cannot be smoothly regulated as in natural muscle. Its mechanical impact is forced onto the natural muscle regardless of the actual condition with regard to metabolism and Ca2+-homeostasis. The development of artificial muscle on the basis of nitinol wires is still in its infancy. The nitinol artificial muscle will have to prove its viability in the various clinical settings.

  16. Surface engineering of artificial heart valve disks using nanostructured thin films deposited by chemical vapour deposition and sol-gel methods.

    PubMed

    Jackson, M J; Robinson, G M; Ali, N; Kousar, Y; Mei, S; Gracio, J; Taylor, H; Ahmed, W

    2006-01-01

    Pyrolytic carbon (PyC) is widely used in manufacturing commercial artificial heart valve disks (HVD). Although PyC is commonly used in HVD, it is not the best material for this application since its blood compatibility is not ideal for prolonged clinical use. As a result thrombosis often occurs and the patients are required to take anti-coagulation drugs on a regular basis in order to minimize the formation of thrombosis. However, anti-coagulation therapy gives rise to some detrimental side effects in patients. Therefore, it is extremely urgent that newer and more technically advanced materials with better surface and bulk properties are developed. In this paper, we report the mechanical properties of PyC-HVD, i.e. strength, wear resistance and coefficient of friction. The strength of the material was assessed using Brinell indentation tests. Furthermore, wear resistance and coefficient of friction values were obtained from pin-on-disk testing. The micro-structural properties of PyC were characterized using XRD, Raman spectroscopy and SEM analysis. Also in this paper we report the preparation of freestanding nanocrystalline diamond films (FSND) using the time-modulated chemical vapour deposition (TMCVD) process. Furthermore, the sol-gel technique was used to uniformly coat PyC-HVD with dense, nanocrystalline-titanium oxide (nc-TiO2) coatings. The as-grown nc-TiO2 coatings were characterized for microstructure using SEM and XRD analysis.

  17. Heart rate responses and technical-tactical aspects of official 5-a-side youth soccer matches played on clay and artificial turf.

    PubMed

    Tessitore, Antonio; Perroni, Fabrizio; Meeusen, Romain; Cortis, Cristina; Lupo, Corrado; Capranica, Laura

    2012-01-01

    Using a randomized crossover design, this study aimed to compare the heart rate (HR) responses and match analysis parameters (i.e., type of action; the number of players involved in an action; the number of passes performed in a collective action; precision of the shots; lost balls; ball interceptions; dribblings; and tackles) of official 5-a-side youth male soccer matches played over 2 pitch surface (i.e., clay vs. artificial turf) conditions. Twenty-two young male soccer players (age 8.3 ± 0.4 years) engaged in 2 consecutive 15-minute periods in each experimental condition. During the match, 53% of HR responses exceeded 85% of the individual HR(peak). No difference emerged between both pitch surfaces and match periods for HR and match analysis indicators. The two 15-minute periods resulted in being appropriate for 8-year-old players, in resembling the intensity of play and the intermittent nature of adult soccer. The similar HR responses and technical-tactical patterns observed on the 2 surfaces indicate that youth match play is not affected by differences in pitch surface. To support the development of individual and team skills of young soccer players, coaches are advised to prioritize game knowledge based on divergent thinking and experience, rather than traditional teaching based on instructions. PMID:22201688

  18. Ovarian responses of dairy buffalo cows to timed artificial insemination protocol, using new or used progesterone devices, during the breeding season (autumn-winter).

    PubMed

    Monteiro, Bruno Moura; de Souza, Diego Cavalcante; Vasconcellos, Guilherme Souza Floriano Machado; Corrêa, Thalita Bueno; Vecchio, Domenico; de Sá Filho, Manoel Francisco; de Carvalho, Nelcio Antonio Tonizza; Baruselli, Pietro Sampaio

    2016-01-01

    This study evaluated the effect of new or used P4 devices on the ovarian responses of dairy buffalo that were administered an estradiol (E2) plus progesterone (P4)-based timed artificial insemination (TAI) protocol during the breeding season. On the first day of the TAI protocol, 142 cows were randomly assigned to receive one of the following: a new device (New; 1.0 g of P4; n = 48); a device that had previously been used for 9 days (Used1x, n = 47); or a device that had previously been used for 18 days (Used2x, n = 47). Ultrasound was used to evaluate the following: the presence of a corpus luteum (CL); the diameter of the dominant follicle (ØDF) during protocol; ovulatory response; and pregnancies per AI (P/AI). Despite similar responses among the treatments, there was a significant positive association of the ØDF during TAI protocol with ovulatory responses and number of pregnancies. In conclusion, satisfactory ovarian responses and a satisfactory pregnancy rate were achieved when grazing dairy buffalo were subjected to the TAI protocol in breeding season, independent of whether a new or used P4 device was used. Furthermore, the presence of the larger follicle was associated with a higher ovulation rate and higher P/AI following TAI.

  19. Dynamic expression profiles of MMPs/TIMPs and collagen deposition in mechanically unloaded rat heart: implications for left ventricular assist device support-induced cardiac alterations.

    PubMed

    Wang, Lu; Xu, Yu-Xian; Du, Xiao-Jie; Sun, Quan-Ge; Tian, Ying-Jun

    2013-09-01

    Left ventricular assist devices (LVADs) ameliorate heart failure by reducing preload and afterload. However, extracellular matrix (ECM) deposition after application of LVADs is not clearly defined. The purpose of the present study was to investigate ECM remodeling after mechanical unloading in a rat heart transplant model. Sixty male Lewis rats were subjected to abdominal heterotopic heart transplantation, and the transplanted hearts were pressure- and volume-unloaded. The age- and weight- matched male Lewis rats who had undergone open thoracic surgeries were used as the control. Left ventricle ECM accumulation and the expression/activity of matrix metalloproteinases (MMPs) and tissue inhibitor of matrix metalloproteinases (TIMPs) were measured on the third, seventh, and fourteenth days after transplantation/sham surgery. Compared with the control group, myocardial ECM deposition significantly increased on the seventh and fourteenth days after heart transplantation (P < 0.05) and peaked on the 14th day. The gelatinase activity as well as mRNA expression of MMP-2 and MMP-9 significantly increased after transplantation (P < 0.05). Both mRNA and protein levels of TIMP-1 and TIMP-2 significantly increased compared with those of the control group. Mechanical unloading may lead to adverse remodeling of the ECM of the left ventricle. The underlying mechanism may due to the imbalance of the MMP/TIMP system, especially the remarkable upregulation of TIMPs in the pressure and volume unloaded heart.

  20. Working Model Hearts

    ERIC Educational Resources Information Center

    Brock, David

    2009-01-01

    Despite student interest, the heart is often a poorly understood topic in biology. To help students understand this vital organ's physiology, the author created this investigation activity involving the mammalian heart and its role in the circulatory system. Students design, build, and demonstrate working artificial "hearts" to exhibit what they…

  1. The AbioCor totally implantable replacement heart.

    PubMed

    Holmes, Elena C

    2003-01-01

    An artificial heart with adequate circulatory support and an acceptable quality of life remains one of the holy grails of heart failure medicine and surgery. The totally implantable AbioCor is powered electrically via an external power source and has no skin-piercing cables. To date, seven critically ill patients with end-stage heart failure have been implanted with it. Four patients survived beyond 2 months, and two patients were discharged from the hospital. Both enjoyed improved quality of life with frequent social excursions; another patient is about to be discharged. While three patients died, early trials suggest that this device holds promise.

  2. Re-use of intravaginal progesterone devices associated with the Short-term Protocol for timed artificial insemination in goats.

    PubMed

    Vilariño, M; Rubianes, E; Menchaca, A

    2011-04-15

    Because intravaginal devices impregnated with 0.3 g of progesterone (i.e., CIDR-G) contain remaining hormone after their use in a Short-term Protocol (5 to 7 d of treatment), the reuse of these devices is proposed in goats. Two experiments were designed to study the effects of the reutilization of CIDR-G, establishing serum progesterone concentrations, follicular development, ovulatory response, and fertility. Experiment 1: Thirty dairy goats received a Short-term Protocol for 5 d using CIDR-G of first use (new devices, n = 10), second use (previously used for 5 d, n = 10), or third use (previously used twice for 5 d each time, n = 10). Goats were given (im) prostaglandin F(2α) (10 mg dinoprost) and eCG (300 IU) at device insertion and withdrawal, respectively. Serum progesterone concentrations induced by CIDR-G of first use were higher than CIDR-G of second or third use (P < 0.05); concentrations were consistently > 1 ng/mL in all females treated with reused devices. Estrus and ovulation were synchronized in 100% of goats (no differences among treatments). All females treated with new devices, but only 80% of females treated with re-used devices ovulated a new follicle that emerged after CIDR-G insertion (P = NS). Ovulation occurred between 60 and 70 h after device removal (no differences among groups). Experiment 2: In goats subjected to a Short-term Protocol followed by AI at 54 h after CIDR-G, pregnancy rates with CIDR-G of first, second, and third use were 75.3% (64/85), 67.4% (60/89), and 62.1% (54/87), respectively (devices of first versus third use, P < 0.05). In summary, intravaginal devices originally containing 0.3 g of progesterone appeared effective to synchronize estrus and ovulation after first, second and third use in the Short-term Protocol. Although the pregnancy rate with reused devices was acceptable (i.e., > 60%), it was significantly lower than that achieved with new devices and further studies to ensure adequate follicular turnover are

  3. Left ventricular assist devices in patients with end-stage heart failure: suggestion of an alternative treatment based on clinically well-known concepts.

    PubMed

    Fantidis, Panayotis; Sánchez, Eladio; Tarhini, Ibrahim; Khan, Ijaz; Pineda, Tomas; Corrales, Juan Antonio; González, José Ramón

    2014-11-01

    Encouraging results were obtained by using left ventricular assist devices (LVADs) in patients with end-stage heart failure (HF) that exhibits extremely high mortality and who were not candidates for heart transplantation. By using this so-called destination therapy (DT), a substantial percentage of these patients achieved sufficient improvement in cardiac function to permit the explantation of the device. The combination of mechanical and pharmacological therapy increased the frequency and durability of myocardial recovery as compared with other therapeutic approaches. Although cardiac transplantation, LVADs, and cardiac resynchronization therapy have provided a major advance in DT, their limitations stimulate the search for alternative therapies. We discuss the limitations of these 3 treatment options for end-stage HF. Also, we propose and discuss the possible advantages of a new intracorporeal procedure that works continuously as intraaortic balloon counterpulsation without an extracorporeal or intracorporeal computer-controlled mechanism. PMID:24482491

  4. Review of Recent Results Using Computational Fluid Dynamics Simulations in Patients Receiving Mechanical Assist Devices for End-Stage Heart Failure

    PubMed Central

    Farag, Mina Berty; Karmonik, Christof; Rengier, Fabian; Loebe, Matthias; Karck, Matthias; von Tengg-Kobligk, Hendrik; Ruhparwar, Arjang; Partovi, Sasan

    2014-01-01

    Many end-stage heart failure patients are not eligible to undergo heart transplantation due to organ shortage, and even those under consideration for transplantation might suffer long waiting periods. A better understanding of the hemodynamic impact of left ventricular assist devices (LVAD) on the cardiovascular system is therefore of great interest. Computational fluid dynamics (CFD) simulations give the opportunity to study the hemodynamics in this patient population using clinical imaging data such as computed tomographic angiography. This article reviews a recent study series involving patients with pulsatile and constant-flow LVAD devices in which CFD simulations were used to qualitatively and quantitatively assess blood flow dynamics in the thoracic aorta, demonstrating its potential to enhance the information available from medical imaging. PMID:25574347

  5. Hybrid approach of ventricular assist device and autologous bone marrow stem cells implantation in end-stage ischemic heart failure enhances myocardial reperfusion

    PubMed Central

    2011-01-01

    We challenge the hypothesis of enhanced myocardial reperfusion after implanting a left ventricular assist device together with bone marrow mononuclear stem cells in patients with end-stage ischemic cardiomyopathy. Irreversible myocardial loss observed in ischemic cardiomyopathy leads to progressive cardiac remodelling and dysfunction through a complex neurohormonal cascade. New generation assist devices promote myocardial recovery only in patients with dilated or peripartum cardiomyopathy. In the setting of diffuse myocardial ischemia not amenable to revascularization, native myocardial recovery has not been observed after implantation of an assist device as destination therapy. The hybrid approach of implanting autologous bone marrow stem cells during assist device implantation may eventually improve native cardiac function, which may be associated with a better prognosis eventually ameliorating the need for subsequent heart transplantation. The aforementioned hypothesis has to be tested with well-designed prospective multicentre studies. PMID:21247486

  6. Value of fault/failure analysis in the medical device regulatory process: the case of the Bjork-Shiley heart valve

    NASA Astrophysics Data System (ADS)

    Hughes, Allen A.; Piehler, Henry R.

    1995-10-01

    A framework of sixteen attributes has been developed for evaluating the effectiveness of the risk management system for FDA regulatory Class III medical devices. Fault/failure analysis was identified as a potentially cost-beneficial attribute. Mechanical heart valves are FDA regulatory Class III devices in that they are considered life-sustaining when working properly, but life-threatening in the event of failure. The benefit-cost difference (net benefit) has been suggested as a measure of effectiveness for individual attributes and defined as the value of averted patient morbidity and mortality. In this paper, the Bjork-Shiley 60 degree convexo- concave mechanical heart valve is subjected to a retrospective benefit-cost analysis for the fault/failure analysis attribute. A general finding is that fault/failure analysis would have been relatively inexpensive for enhancing the risk management system for the Bjork-Shiley heart valve - less than $25,000 - while having the potential to avert 151 mortalities. Even without placing a value-of-life figure on averted mortalities, fault/failure analysis would have been cost-beneficial in reducing the risk of morbidity from mechanical heart valve failure.

  7. A modified technique for implantation of the HeartWare™ left ventricular assist device when using bivalirudin anticoagulation in patients with acute heparin-induced thrombocytopenia

    PubMed Central

    Morshuis, Michiel; Boergermann, Jochen; Gummert, Jan; Koster, Andreas

    2013-01-01

    In patients with acute heparin-induced thrombocytopenia (HIT) needing urgent cardiac surgery, bivalirudin is recommended as a first-line strategy for intraoperative anticoagulation. However, due to the unique elimination process of bivalirudin, careful adjustment of the perfusion and surgical strategy is mandatory as blood stasis in the circuit or prolonged interruption of areas or compartments containing blood from the systemic circulation may result in thrombus formation. We report here a modified surgical strategy for the implantation of the HeartWare™ left ventricular assist device, which avoids prolonged disconnection of the blood-filled device from the systemic blood flow, so that bivalirudin can be safely used as anticoagulant. PMID:23628649

  8. Biventricular Finite Element Modeling of the Acorn CorCap Cardiac Support Device on a Failing Heart

    PubMed Central

    Wenk, Jonathan F.; Ge, Liang; Zhang, Zhihong; Mojsejenko, Dimitri; Potter, D. Dean; Tseng, Elaine E.; Guccione, Julius M.; Ratcliffe, Mark B.

    2013-01-01

    Background The Acorn CorCap Cardiac Support Device (CSD; Acorn Cardiovascular Inc, St. Paul, MN) is a woven polyester jacket that is placed around the heart and designed to reverse the progressive remodeling associated with dilated cardiomyopathy. However, the effects of the Acorn CSD on myofiber stress and ventricular function remain unknown. We tested the hypothesis that the Acorn CSD reduces end-diastolic (ED) myofiber stress. Methods A previously described weakly coupled biventricular finite element (FE) model and circulatory model based on magnetic resonance images of a dog with dilated cardiomyopathy was used. Virtual applications of the CSD alone (Acorn), CSD with rotated fabric fiber orientation (rotated), CSD with 5% prestretch (tight), and CSD wrapped only around the left ventricle (LV; LV-only) were performed, and the effect on myofiber stress at ED and pump function was calculated. Results The Acorn CSD has a large effect on ED myofiber stress in the LV free wall, with reductions of 55%, 79%, 92%, and 40% in the Acorn, rotated, tight, and LV-only cases, respectively. However, there is a tradeoff in which the Acorn CSD reduces stroke volume at LV end-diastolic pressure of 8 mm Hg by 23%, 25%, 30%, and 7%, respectively, in the Acorn, rotated, tight, and LV-only cases. Conclusions The Acorn CSD significantly reduces ED myofiber stress. However, CSD wrapped only around the LV was the only case with minimal negative effect on pump function. Findings suggest that LV-only CSD and Acorn fabric orientation should be optimized to allow maximal myofiber stress reduction with minimal reduction in pump function. PMID:23643546

  9. Calciotropic and Phosphaturic Hormones in End-Stage Heart Failure Patients Supported by a Left-Ventricular Assist Device

    PubMed Central

    Zittermann, Armin

    2016-01-01

    Background Calcium and phosphate are central for myocardial contractility and energy metabolism, and low levels of the calciotropic hormone 1,25-dihydroxyvitamin D (1,25(OH)2D), as well as high levels of the phosphaturic hormone fibroblast growth factor (FGF)-23, are independently associated with poor clinical outcome in heart failure (HF) patients. We therefore aimed to investigate the postoperative time course of the aforementioned hormones in HF patients supported with a left-ventricular assist device (LVAD) implant. Methods For the present study, stored biobank plasma samples of 69 patients, collected before LVAD implantation (t0) and 12 days (t1), 30 days (t2), 83 days (t3), and 300 days (t4) post-intervention, were used to measure circulating FGF-23, parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD), 1,25(OH)2D, and kidney function. Results Most patients were male and had baseline INTERMACS levels and cardiac index values ≤ 3 and ≤ 2.7 L/min/m2, respectively. There were significant time effects on estimated glomerular filtration rate (eGFR), FGF-23 and 1,25(OH)2D, but not on PTH or 25OHD. Notably, eGFR values increased and FGF-23 levels decreased only transiently, whereas 1,25(OH)2D increased continuously until t4. The rise in 1,25(OH)2D was largely influenced by those patients who survived the first post-implant year, and was not seen in non-survivors. Variations in 1,25(OH)2D levels could only partly be explained by eGFR values or FGF-23, 25OHD, and PTH levels (multiple R2 = 0.305;P<0.001). Conclusions The present study indicates that LVAD implantation has only transient effects on circulating FGF-23 levels, but is associated with a continuous increase in circulating 1,25(OH)2D levels, especially in survivors. PMID:27788150

  10. Who Needs Heart Surgery?

    MedlinePlus

    ... disease (CHD) Fix heart valves that don't work well Control abnormal heart rhythms Place medical devices Replace a damaged heart with a healthy one If other treatments—such as lifestyle changes, medicines, and medical ... surgeon will work with you to decide whether you need heart ...

  11. A novel distributed model of the heart under normal and congestive heart failure conditions.

    PubMed

    Ravanshadi, Samin; Jahed, Mehran

    2013-04-01

    Conventional models of cardiovascular system frequently lack required detail and focus primarily on the overall relationship between pressure, flow and volume. This study proposes a localized and regional model of the cardiovascular system. It utilizes noninvasive blood flow and pressure seed data and temporal cardiac muscle regional activity to predict the operation of the heart under normal and congestive heart failure conditions. The analysis considers specific regions of the heart, namely, base, mid and apex of left ventricle. The proposed method of parameter estimation for hydraulic electric analogy model is recursive least squares algorithm. Based on simulation results and comparison to clinical data, effect of congestive heart failure in the heart is quantified. Accumulated results for simulated ejection fraction percentage of the apex, mid and base regions of the left ventricle in congestive heart failure condition were 39 ± 6, 36 ± 9 and 38 ± 8, respectively. These results are shown to satisfactorily match those found through clinical measurements. The proposed analytical method can in effect be utilized as a preclinical and predictive tool for high-risk heart patients and candidates for heart transplant, assistive device and total artificial heart.

  12. Comparison of four different mobile devices for measuring heart rate and ECG with respect to aspects of usability and acceptance by older people.

    PubMed

    Ehmen, Hilko; Haesner, Marten; Steinke, Ines; Dorn, Mario; Gövercin, Mehmet; Steinhagen-Thiessen, Elisabeth

    2012-05-01

    In the area of product design and usability, most products are developed for the mass-market by technically oriented designers and developers for use by persons who themselves are also technically adept by today's standards. The demands of older people are commonly not given sufficient consideration within the early developmental process. In the present study, the usability and acceptability of four different devices meant to be worn for the measurement of heart rate or ECG were analyzed on the basis of qualitative subjective user ratings and structured interviews of twelve older participants. The data suggest that there was a relatively high acceptance concerning these belts by older adults but none of the four harnesses was completely usable. Especially problematic to the point of limiting satisfaction among older subjects were problems encountered while adjusting the length of the belt and/or closing the locking mechanism. The two devices intended for dedicated heart rate recording yielded the highest user ratings for design, and were clearly preferred for extended wearing time. Yet for all the devices participants identified several important deficiencies in their design, as well as suggestions for improvement. We conclude that the creation of an acceptable monitoring device for older persons requires designers and developers to consider the special demands and abilities of the target group.

  13. Artificial muscle: the human chimera is the future.

    PubMed

    Tozzi, P

    2011-12-14

    Severe heart failure and cerebral stroke are broadly associated with the impairment of muscular function that conventional treatments struggle to restore. New technologies enable the construction of "smart" materials that could be of great help in treating diseases where the main problem is muscle weakness. These materials "behave" similarly to biological systems, because the material directly converts energy, for example electrical energy into movement. The extension and contraction occur silently like in natural muscles. The real challenge is to transfer this amazing technology into devices that restore or replace the mechanical function of failing muscle. Cardiac assist devices based on artificial muscle technology could envelope a weak heart and temporarily improve its systolic function, or, if placed on top of the atrium, restore the atrial kick in chronic atrial fibrillation. Artificial sphincters could be used to treat urinary incontinence after prostatectomy or faecal incontinence associated with stomas. Artificial muscles can restore the ability of patients with facial paralysis due to stroke or nerve injury to blink. Smart materials could be used to construct an artificial oesophagus including peristaltic movement and lower oesophageal sphincter function to replace the diseased oesophagus thereby avoiding the need for laparotomy to mobilise stomach or intestine. In conclusion, in the near future, smart devices will integrate with the human body to fill functional gaps due to organ failure, and so create a human chimera.

  14. Percutaenous mitral valve: A non-stented coronary sinus device for the treatment of functional mitral regurgitation in heart failure patients.

    PubMed

    Sack, Stefan; Kahlert, Philipp; Erbel, Raimund

    2009-01-01

    Functional mitral regurgitation in heart failure limits survival in a severity-graded fashion. Even mild mitral regurgitation doubles mortality risk. We report the use of a non-stented coronary sinus device to reduce mitral annulus dimension in order to re-establish mitral valve competence. The device (PTMA, Viacor, Inc., Wilmington, MA, USA) consists of a multi-lumen PTFE (Teflon) PTMA catheter in which Nitinol (nickel-titanium alloy) treatment rods are advanced. For individual use up to three rods of different length and stiffness can be used. Therefore dimension reduction can be performed in an incremental fashion. Fluoroscopy and 3 D echocardiography are performed throughout the procedure to visiualize the positioning and confirm maximum treatment effect. The case describes the use and the effect of PTMA treatment. Safety and efficacy of the PTMA device will be investigated in the upcoming PTOLEMY 2 trial.

  15. Percutaenous mitral valve: A non-stented coronary sinus device for the treatment of functional mitral regurgitation in heart failure patients.

    PubMed

    Sack, Stefan; Kahlert, Philipp; Erbel, Raimund

    2009-01-01

    Functional mitral regurgitation in heart failure limits survival in a severity-graded fashion. Even mild mitral regurgitation doubles mortality risk. We report the use of a non-stented coronary sinus device to reduce mitral annulus dimension in order to re-establish mitral valve competence. The device (PTMA, Viacor, Inc., Wilmington, MA, USA) consists of a multi-lumen PTFE (Teflon) PTMA catheter in which Nitinol (nickel-titanium alloy) treatment rods are advanced. For individual use up to three rods of different length and stiffness can be used. Therefore dimension reduction can be performed in an incremental fashion. Fluoroscopy and 3 D echocardiography are performed throughout the procedure to visiualize the positioning and confirm maximum treatment effect. The case describes the use and the effect of PTMA treatment. Safety and efficacy of the PTMA device will be investigated in the upcoming PTOLEMY 2 trial. PMID:19431068

  16. First in vitro cycle of the chicken mite, Dermanyssus gallinae (DeGeer 1778), utilizing an artificial feeding device.

    PubMed

    Bruneau, A; Dernburg, A; Chauve, C; Zenner, L

    2001-12-01

    The red poultry mite, Dermanyssus gallinae, is one of the most economically deleterious ecto-parasites of layer hens worldwide. D. gallinae is difficult to eliminate from infested poultry farms, and even to study, because it resides on the host only during the bloodmeal at night, and hides in the crevices of poultry houses during the day. Here, the life-cycle of D. gallinae was reproduced entirely in vitro. Mites were incubated in a glass pipette at 30 degrees C, 60-95 degrees relative humidity and total darkness. A feeding apparatus, composed of a membrane, reservoir and blood was fitted on the pipette during bloodmeals. We tested feeding rates on blood mixed with 1 of 3 anti-coagulants (EDTA, heparin and trisodium citrate) at different concentrations, and biological and artificial membranes. The best engorgement and survival rates for all 3 haematophagous life-stages of the parasite were observed in 1-day-old chick membranes and heparinized (0.02 mmo/ml) blood. We then describe the steps in developing a complete self-sustaining in vitro life-cycle. A colony of mites was maintained in vitro for 7 generations. Losses in the first generation were heavy, but survival had multiplied 5-fold by the fifth generation. We hypothesize that heavy mortality rates during the first life-cycle correspond to selective pressure: only the mites which fed and survived in vitro were able to reproduce.

  17. 21 CFR 886.3200 - Artificial eye.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Artificial eye. 886.3200 Section 886.3200 Food and... OPHTHALMIC DEVICES Prosthetic Devices § 886.3200 Artificial eye. (a) Identification. An artificial eye is a device resembling the anterior portion of the eye, usually made of glass or plastic, intended to...

  18. 21 CFR 886.3200 - Artificial eye.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Artificial eye. 886.3200 Section 886.3200 Food and... OPHTHALMIC DEVICES Prosthetic Devices § 886.3200 Artificial eye. (a) Identification. An artificial eye is a device resembling the anterior portion of the eye, usually made of glass or plastic, intended to...

  19. 21 CFR 886.3200 - Artificial eye.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Artificial eye. 886.3200 Section 886.3200 Food and... OPHTHALMIC DEVICES Prosthetic Devices § 886.3200 Artificial eye. (a) Identification. An artificial eye is a device resembling the anterior portion of the eye, usually made of glass or plastic, intended to...

  20. 21 CFR 886.3200 - Artificial eye.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Artificial eye. 886.3200 Section 886.3200 Food and... OPHTHALMIC DEVICES Prosthetic Devices § 886.3200 Artificial eye. (a) Identification. An artificial eye is a device resembling the anterior portion of the eye, usually made of glass or plastic, intended to...

  1. 21 CFR 886.3200 - Artificial eye.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Artificial eye. 886.3200 Section 886.3200 Food and... OPHTHALMIC DEVICES Prosthetic Devices § 886.3200 Artificial eye. (a) Identification. An artificial eye is a device resembling the anterior portion of the eye, usually made of glass or plastic, intended to...

  2. Smart x-ray beam position monitor system using artificial intelligence methods for the Advanced Photon Source insertion-device beamlines

    SciTech Connect

    Shu, D.; Ding, H.; Barraza, J.; Kuzay, T.M.; Haeffner, D.; Ramanathan, M.

    1997-09-01

    At the Advanced Photon Source (APS), each insertion device (ID) beamline front-end has two XBPMs to monitor the X-ray beam position for both that vertical and horizontal directions. Performance challenges for a conventional photoemission type X-ray beam position monitor (XBPM) during operations are contamination of the signal from the neighboring bending magnet sources and the sensitivity of the XBPM to the insertion device (ID) gap variations. Problems are exacerbated because users change the ID gap during their operations, and hence the percentage level of the contamination in the front end XBPM signals varies. A smart XBPM system with a high speed digital signal processor has been built at the Advanced Photon Source for the ID beamline front ends. The new version of the software, which uses an artificial intelligence method, provides a self learning and self-calibration capability to the smart XBPM system. The structure of and recent test results with the system are presented in this paper.

  3. The Application of Bileaflet Mechanical Heart Valves in the Polish Ventricular Assist Device: Physical and Numerical Study and First Clinical Usage.

    PubMed

    Malota, Zbigniew; Sadowski, Wojciech; Krzyskow, Marek; Stolarzewicz, Bogdan

    2016-03-01

    The Polish ventricular assist device (Polvad) has been used successfully in clinical contexts for many years. The device contains two single-disc valves, one at the inlet and one at the outlet connector of the pneumatic pump. Unfortunately, in recent years, a problem has occurred with the availability of single-disc valves. This article presents the possibility of using bileaflet mechanical heart valve prostheses in the Polvad to avoid a discontinuity in clinical use. The study is based on experimental and numerical simulations and comparison of the distribution of flow, pressure, and stress (wall, shear, and turbulent) inside the Polvad chamber and the inlet/outlet connectors fitted with Sorin Monodisc and Sorin Bicarbon Fitline valves. The type and orientation of the inlet valve affects valve performance and flow distribution inside the chamber. Near-wall flow is observed for single-disc valves. In the case of bileaflet valves, the main jet is directed more centrally, with lower shear stress but higher turbulent stress in comparison with single-disc valves. For clinical usage, a 45° orientation of the bileaflet inlet valve was chosen, as this achieves good washing of the inlet area near the membrane paste surface. The Polvad with bileaflet valves has now been used successfully in our clinic for over a year and will continue to be used until new assist devices for heart support are developed.

  4. Assessment and management of right ventricular failure in left ventricular assist device patients.

    PubMed

    Holman, William L; Acharya, Deepak; Siric, Franjo; Loyaga-Rendon, Renzo Y

    2015-01-01

    Mechanical circulatory support devices, including ventricular assist devices (VADs) and the total artificial heart, have evolved to become accepted therapeutic options for patients with severe congestive heart failure. Continuous-flow left VADs are the most prevalent option for mechanical circulatory assistance and reliably provide years of support. However, problems related to acute and chronic right heart failure in patients with left VADs continue to cause important mortality and morbidity. This review discusses the assessment and management of right ventricular failure in left VAD patients. The goal is to summarize current knowledge and suggest new approaches to managing this problem.

  5. Cardiac status assessment with a multi-signal device for improved home-based congestive heart failure management.

    PubMed

    Muehlsteff, Jens; Carvalho, Paulo; Henriques, Jorge; Paiva, Rui P; Reiter, Harald

    2011-01-01

    State-of-the-Art disease management for Congestive Heart Failure (CHF) patients is still based on easy-to-acquire measures such as heart rate (HR), weight and blood pressure (BP). However, these measures respond late to changes of the patient health status and provide limited information to personalize and adapt medication therapy. This paper describes our concept called "Cardiac Status Assessment" we have been investigating within the European project "HeartCycle" towards next-generation home-based disease management of CHF. In our concept we analyze non-invasive surrogate measures of the cardio-vascular function in particular systolic time intervals and pulse wave characteristics to estimate Cardiac Output (CO) and Systemic Vascular Resistance (SVR) both are established clinical measures. We discuss the underlying concept, a developed measurement system and first results. PMID:22254450

  6. Levitronix ventricular assist devices as a bridge to recovery after profound biventricular heart failure associated with pulmonary aspergillosis.

    PubMed

    Whitson, Bryan A; D'Cunha, Jonathan; Knutsen, Amy C; Boyle, Andrew J; Liao, Kenneth K

    2007-04-01

    A patient with multisystem organ failure and refractory cardiopulmonary shock stemming from Aspergillus pneumonia was treated with 2 Levitronix ventricular assist devices as a bridge-to-recovery. After ventricular assist device placement, the patient recovered myocardial function. The ventricular assist devices were removed on post-implant Day 7, and the patient made a full long-term recovery. Ventricular assist devices should be strongly considered, as bridges to recovery, to support patients with acute myocardial dysfunction associated with sepsis while the underlying infection is treated. PMID:17403475

  7. Evaluating the Potential for Marine and Hydrokinetic Devices to Act as Artificial Reefs or Fish Aggregating Devices. Based on Analysis of Surrogates in Tropical, Subtropical, and Temperate U.S. West Coast and Hawaiian Coastal Waters

    SciTech Connect

    Kramer, Sharon H.; Hamilton, Christine D.; Spencer, Gregory C.; Ogston, Heather O.

    2015-05-12

    Wave energy converters (WECs) and tidal energy converters (TECs) are only beginning to be deployed along the U.S. West Coast and in Hawai‘i, and a better understanding of their ecological effects on fish, particularly on special-status fish (e.g., threatened and endangered) is needed to facilitate project design and environmental permitting. The structures of WECs and TECs placed on to the seabed, such as anchors and foundations, may function as artificial reefs that attract reef-associated fishes, while the midwater and surface structures, such as mooring lines, buoys, and wave or tidal power devices, may function as fish aggregating devices (FADs), forming the nuclei for groups of fishes. Little is known about the potential for WECs and TECs to function as artificial reefs and FADs in coastal waters of the U.S. West Coast and Hawai‘i. We evaluated these potential ecological interactions by reviewing relevant information about fish associations with surrogate structures, such as artificial reefs, natural reefs, kelps, floating debris, oil and gas platforms, marine debris, anchored FADs deployed to enhance fishing opportunities, net-cages used for mariculture, and piers and docks. Based on our review, we postulate that the structures of WECs and TECs placed on or near the seabed in coastal waters of the U.S. West Coast and Hawai‘i likely will function as small-scale artificial reefs and attract potentially high densities of reef-associated fishes (including special-status rockfish species [Sebastes spp.] along the mainland), and that the midwater and surface structures of WECs placed in the tropical waters of Hawai‘i likely will function as de facto FADs with species assemblages varying by distance from shore and deployment depth. Along the U.S. West Coast, frequent associations with midwater and surface structures may be less likely: juvenile, semipelagic, kelp-associated rockfishes may occur at midwater and surface structures of WECs in coastal waters of

  8. Implementation and reimbursement of remote monitoring for cardiac implantable electronic devices in Europe: a survey from the health economics committee of the European Heart Rhythm Association.

    PubMed

    Mairesse, Georges H; Braunschweig, Frieder; Klersy, Katherine; Cowie, Martin R; Leyva, Francisco

    2015-05-01

    Remote monitoring (RM) of cardiac implantable electronic devices (CIEDs) permits early detection of arrhythmias, device, and lead failure and may also be useful in risk-predicting patient-related outcomes. Financial benefits for patients and healthcare organizations have also been shown. We sought to assess the implementation and funding of RM of CIEDs, including conventional pacemakers (PMs), implantable cardioverter defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices in Europe. Electronic survey from 43 centres in 15 European countries. In the study sample, RM was available in 22% of PM patients, 74% of ICD patients, and 69% of CRT patients. The most significant perceived benefits were the early detection of atrial arrhythmias in pacemaker patients, lead failure in ICD patients, and worsening heart failure in CRT patients. Remote monitoring was reported to lead a reduction of in-office follow-ups for all devices. The most important reported barrier to the implementation of RM for all CIEDs was lack of reimbursement (80% of centres). Physicians regard RM of CIEDs as a clinically useful technology that affords significant benefits for patients and healthcare organizations. Remote monitoring, however, is perceived as increasing workload. Reimbursement for RM is generally perceived as a major barrier to implementation.

  9. Complications of Lumbar Artificial Disc Replacement Compared to Fusion: Results From the Prospective, Randomized, Multicenter US Food and Drug Administration Investigational Device Exemption Study of the Charité Artificial Disc

    PubMed Central

    Majd, Mohammed E.; Isaza, Jorge E.; Blumenthal, Scott L.; McAfee, Paul C.; Guyer, Richard D.; Hochschuler, Stephen H.; Geisler, Fred H.; Garcia, Rolando; Regan, John J.

    2007-01-01

    Background Previous reports of lumbar total disc replacement (TDR) have described significant complications. The US Food and Drug Administration (FDA) investigational device exemption (IDE) study of the Charité artificial disc represents the first level I data comparison of TDR to fusion. Methods In the prospective, randomized, multicenter IDE study, patients were randomized in a 2:1 ratio, with 205 patients in the Charité group and 99 patients in the control group (anterior lumbar interbody fusion [ALIF] with BAK cages). Inclusion criteria included confirmed single-level degenerative disc disease at L4-5 or L5-S1 and failure of nonoperative treatment for at least 6 months. Complications were reported throughout the study. Results The rate of approach-related complications was 9.8% in the investigational group and 10.1% in the control group. The rate of major neurological complications was similar between the 2 groups (investigational = 4.4%, control = 4.0%). There was a higher rate of superficial wound infection in the investigational group but no deep wound infections in either group. Pseudarthrosis occurred in 9.1% of control group patients. The rate of subsidence in the investigational group was 3.4%. The reoperation rate was 5.4% in the investigational group and 9.1% in the control group. Conclusions The incidence of perioperative and postoperative complications for lumbar TDR was similar to that of ALIF. Vigilance is necessary with respect to patient indications, training, and correct surgical technique to maintain TDR complications at the levels experienced in the IDE study. PMID:25802575

  10. Triple bridge to simultaneous heart and kidney transplantation.

    PubMed

    El-Sayed Ahmed, Magdy M; Aftab, Muhammad; Singh, Steve K; Mallidi, Hari R; Frazier, Oscar H

    2014-08-01

    We report a 40-year-old man who presented with irreversible cardiogenic shock. The patient was treated with three consecutive stages of mechanical circulatory support as a triple bridge to cardiac transplantation. Extracorporeal membrane oxygenation support was used for 5 days, followed by Levitronix CentriMag biventricular assist devices for 39 days. This was escalated to implantation of the CardioWest temporary total artificial heart for 107 days. The patient experienced concurrent end-stage renal disease and subsequently underwent both heart and kidney transplantation. On postoperative day 18 the patient was discharged with good cardiac and renal function.

  11. Heart Health - Brave Heart

    MedlinePlus

    ... Bar Home Current Issue Past Issues Cover Story Heart Health Brave Heart Past Issues / Winter 2009 Table of Contents For ... you can have a good life after a heart attack." Lifestyle Changes Surviving—and thriving—after such ...

  12. Incessant tachycardia in a patient with advanced heart failure and left ventricular assist device: What is the mechanism?

    PubMed

    Noheria, Amit; Mulpuru, Siva K; Noseworthy, Peter A; Asirvatham, Samuel J

    2016-01-01

    We present a case of incessant wide-complex tachycardia in a patient with left-ventricular assist device, and discuss the differential diagnosis with an in-depth analysis of the intracardiac tracings during the invasive electrophysiologic study, including interpretation of the relative timing of the fascicular signals during tachycardia and in sinus rhythm, and interpretation of pacing and entrainment maneuvers. PMID:27485564

  13. Improvement of cardiac sarcoplasmic reticulum calcium cycling in dogs with heart failure following long-term therapy with the Acorn Cardiac Support Device.

    PubMed

    Gupta, Ramesh C; Mishra, Sudhish; Rastogi, Sharad; Sharov, Victor G; Sabbah, Hani N

    2005-06-01

    Abnormal Ca(2+)-homeostasis is a hall-marked characteristic of the failing heart. In the normal myocardium, the sarcoplasmic reticulum (SR) is a principal organelle that controls intracellular Ca(2+) concentration during the cardiac cycle. The SR consists of longitudinal and terminal cisternea regions. The former contains the Ca(2+)-ATPase pump or SERCA-2a whose function is to transport cytosolic Ca(2+) into the lumen of the SR during diastole and whose activity is regulated by reversible phosphorylation of the endogenously SR-bound phospholamban (PLB). The SR's terminal cisternea region contains ryanodine-sensitive Ca(2+)-release channels (RR), the activity of which is regulated by direct and indirect reversible phosphorylation. These channels release the SR-stored Ca(2+) during contraction. We have shown that in left ventricular (LV) myocardium from dogs with coronary microembolization-induced heart failure, ability of the SR to sequester and release Ca(2+) during the cardiac cycles is impaired. This abnormality was associated with reduced expression (protein and mRNA) levels of Ca(2+)-ATPase, PLB, and reduced PLB phosphorylation. Long-term therapy with the Acorn Cardiac Support Device (CSD) is associated with restoration of the ability of the SR to sequester Ca(2+). This improvement in SR function following chronic CSD therapy was due primarily to increased affinity of the SERCA-2a for calcium. The later was associated with (1) increased phosphorylation of PLB at serine 16 and threonine 17, (2) unchanged protein expression of PLB and (3) unchanged protein expression of SERCA-2a in LV myocardium of CSD-treated dogs compared to controls. This review summarizes our current understanding of the role of the CSD in modulating SR calcium cycling in an experimental canine model of chronic heart failure produced by multiple sequential intracoronary microembolizations. PMID:16258722

  14. Using medical imaging for the detection of adverse events ("incidents") during the utilization of left ventricular assist devices in adult patients with advanced heart failure.

    PubMed

    Kaufmann, Friedrich; Krabatsch, Thomas

    2016-05-01

    Ventricular assist devices (VAD) are used for mechanical support of the terminally failing heart. Failure of these life supporting systems can be fatal. Early and reliable detection of any upcoming problems is mandatory and is crucial for the outcome. Medical imaging methods are described within this review, which are not only essential for diagnosis of typically VAD-related complications but also for the detection or verification of technical issues. Within this review the utilization of medical imaging equipment for the diagnosis of technical malfunctions or damages of implanted system components is discussed. A newly developed specialized acoustic imaging method for pump thrombosis detection will also be described along with the most common VAD-related medical complications and their respective imaging methods and the limitations induced by the use of the VAD-system.

  15. Effect of counter-pulsation control of a pulsatile left ventricular assist device on working load variations of the native heart

    PubMed Central

    2014-01-01

    Background When using a pulsatile left ventricular assist device (LVAD), it is important to reduce the cardiac load variations of the native heart because severe cardiac load variations can induce ventricular arrhythmia. In this study, we investigated the effect of counter-pulsation control of the LVAD on the reduction of cardiac load variation. Methods A ventricular electrocardiogram-based counter-pulsation control algorithm for a LVAD was implemented, and the effects of counter-pulsation control of the LVAD on the reduction of the working load variations of the left ventricle were determined in three animal experiments. Results Deviations of the working load of the left ventricle were reduced by 51.3%, 67.9%, and 71.5% in each case, and the beat-to-beat variation rates in the working load were reduced by 84.8%, 82.7%, and 88.2% in each ease after counter-pulsation control. There were 3 to 12 premature ventricle contractions (PVCs) before counter-pulsation control, but no PVCs were observed during counter-pulsation control. Conclusions Counter-pulsation control of the pulsatile LVAD can reduce severe cardiac load variations, but the average working load is not markedly affected by application of counter-pulsation control because it is also influenced by temporary cardiac outflow variations. We believe that counter-pulsation control of the LVAD can improve the long-term safety of heart failure patients equipped with LVADs. PMID:24708625

  16. Heart Failure

    MedlinePlus

    ... version of this page please turn Javascript on. Heart Failure What is Heart Failure? In heart failure, the heart cannot pump enough ... failure often experience tiredness and shortness of breath. Heart Failure is Serious Heart failure is a serious and ...

  17. The LionHeart LVD-2000: a completely implanted left ventricular assist device for chronic circulatory support.

    PubMed

    Mehta, S M; Pae, W E; Rosenberg, G; Snyder, A J; Weiss, W J; Lewis, J P; Frank, D J; Thompson, J J; Pierce, W S

    2001-03-01

    Management of patients with end-stage cardiac disease remains a vexing problem. Limitations in medical management and a fixed supply of donor organs for cardiac transplant have a continued impact on this growing population of patients. Mechanical circulatory support has proved very successful as a means of bridging patients to cardiac transplant when all medical options have been exhausted. The development of a chronic system of circulatory support has been underway at the Pennsylvania State University for nearly 30 years. These efforts have been recently merged with the industrial partnership with Arrow International toward the development of the LionHeart LVD-2000 (Arrow International, Reading, PA) completely implanted left ventricular support system. We present an overview of the system, details of implantation, a review of preclinical studies, and a synopsis of the first European implants. Early results have demonstrated the system to be safe, effective, and reliable. Transcutaneous energy transmission and the compliance chamber have been validated.

  18. Artificial muscles on heat

    NASA Astrophysics Data System (ADS)

    McKay, Thomas G.; Shin, Dong Ki; Percy, Steven; Knight, Chris; McGarry, Scott; Anderson, Iain A.

    2014-03-01

    Many devices and processes produce low grade waste heat. Some of these include combustion engines, electrical circuits, biological processes and industrial processes. To harvest this heat energy thermoelectric devices, using the Seebeck effect, are commonly used. However, these devices have limitations in efficiency, and usable voltage. This paper investigates the viability of a Stirling engine coupled to an artificial muscle energy harvester to efficiently convert heat energy into electrical energy. The results present the testing of the prototype generator which produced 200 μW when operating at 75°C. Pathways for improved performance are discussed which include optimising the electronic control of the artificial muscle, adjusting the mechanical properties of the artificial muscle to work optimally with the remainder of the system, good sealing, and tuning the resonance of the displacer to minimise the power required to drive it.

  19. Heart MRI

    MedlinePlus

    Magnetic resonance imaging - cardiac; Magnetic resonance imaging - heart; Nuclear magnetic resonance - cardiac; NMR - cardiac; MRI of the heart; Cardiomyopathy - MRI; Heart failure - MRI; Congenital heart disease - MRI

  20. New electromagnetic methods for the evaluation of prosthetic heart valves (invited)

    NASA Astrophysics Data System (ADS)

    Udpa, Satish

    2002-05-01

    Prosthetic devices are being implanted at record levels as the nation "ages" and advances in prosthetic science are made. Devices that are implanted range from artificial limbs and hips to devices such as heart valves. Periodic evaluation of the state of the devices is of significant interest particularly in the case of prosthetics whose failure can be fatal. An example of such a device is the artificial heart valve. Heart valves are usually replaced when stenosis or incompetence is indicated. This article presents a selection of some new techniques that are being developed for the detection of outlet strut failures in Bjork-Shiley heart valves. Methods that show particular promise include a noninvasive electromagnetic method that relies on the excitation and measurement of the resonant vibration modes of the strut. An alternate approach involves the induction of currents in the outlet strut using a pair of external excitation coils. The field generated by the current induced in the strut perturbs the field generated by the excitation coils. The field perturbations are measured using a catheter-mounted gradiometer. Test results obtained using an experimental rig designed to demonstrate the proof-of-concept are presented.

  1. Devices for Arrhythmia

    MedlinePlus

    ... the heart an electric shock (as with a defibrillator ). For people with recurrent arrhythmias, medical devices such as a pacemaker and implantable cardioverter defibrillator (ICD) can help by continuously monitoring the heart's ...

  2. Comparative Analysis of the Equivital EQ02 Lifemonitor with Holter Ambulatory ECG Device for Continuous Measurement of ECG, Heart Rate, and Heart Rate Variability: A Validation Study for Precision and Accuracy

    PubMed Central

    Akintola, Abimbola A.; van de Pol, Vera; Bimmel, Daniel; Maan, Arie C.; van Heemst, Diana

    2016-01-01

    Background: The Equivital (EQ02) is a multi-parameter telemetric device offering both real-time and/or retrospective, synchronized monitoring of ECG, HR, and HRV, respiration, activity, and temperature. Unlike the Holter, which is the gold standard for continuous ECG measurement, EQO2 continuously monitors ECG via electrodes interwoven in the textile of a wearable belt. Objective: To compare EQ02 with the Holter for continuous home measurement of ECG, heart rate (HR), and heart rate variability (HRV). Methods: Eighteen healthy participants wore, simultaneously for 24 h, the Holter and EQ02 monitors. Per participant, averaged HR, and HRV per 5 min from the two devices were compared using Pearson correlation, paired T-test, and Bland-Altman analyses. Accuracy and precision metrics included mean absolute relative difference (MARD). Results: Artifact content of EQ02 data varied widely between (range 1.93–56.45%) and within (range 0.75–9.61%) participants. Comparing the EQ02 to the Holter, the Pearson correlations were respectively 0.724, 0.955, and 0.997 for datasets containing all data and data with < 50 or < 20% artifacts respectively. For datasets containing respectively all data, data with < 50, or < 20% artifacts, bias estimated by Bland-Altman analysis was −2.8, −1.0, and −0.8 beats per minute and 24 h MARD was 7.08, 3.01, and 1.5. After selecting a 3-h stretch of data containing 1.15% artifacts, Pearson correlation was 0.786 for HRV measured as standard deviation of NN intervals (SDNN). Conclusions: Although the EQ02 can accurately measure ECG and HRV, its accuracy and precision is highly dependent on artifact content. This is a limitation for clinical use in individual patients. However, the advantages of the EQ02 (ability to simultaneously monitor several physiologic parameters) may outweigh its disadvantages (higher artifact load) for research purposes and/ or for home monitoring in larger groups of study participants. Further studies can be aimed

  3. Biocompatibility of implantable biomedical devices

    NASA Astrophysics Data System (ADS)

    Lyu, Suping

    2008-03-01

    Biomedical devices have been broadly used to treat human disease, especially chronic diseases where pharmaceuticals are less effective. Heart valve and artificial joint are examples. Biomedical devices perform by delivering therapies such as electric stimulations, mechanical supports and biological actions. While the uses of biomedical devices are highly successful they can trigger adverse biological reactions as well. The property that medical devices perform with intended functions but not causing unacceptable adverse effects was called biocompatibility in the early time. As our understanding of biomaterial-biological interactions getting broader, biocompatibility has more meanings. In this talk, I will present some adverse biological reactions observed with implantable biomedical devices. Among them are surface fouling of implantable sensors, calcification with vascular devices, restenosis with stents, foreign particle migration and mechanical fractures of devices due to inflammation reactions. While these effects are repeatable, there are very few quantitative data and theories to define them. The purpose of this presentation is to introduce this biocompatibility concept to biophysicists to stimulate research interests at different angles. An open question is how to quantitatively understand the biocompatibility that, like many other biological processes, has not been quantified experimentally.

  4. Artificial Intelligence.

    ERIC Educational Resources Information Center

    Waltz, David L.

    1982-01-01

    Describes kinds of results achieved by computer programs in artificial intelligence. Topics discussed include heuristic searches, artificial intelligence/psychology, planning program, backward chaining, learning (focusing on Winograd's blocks to explore learning strategies), concept learning, constraint propagation, language understanding…

  5. Heart Research

    NASA Technical Reports Server (NTRS)

    1991-01-01

    James Antaki and a group of researchers from the University of Pittsburgh School of Medicine used many elements of the Technology Utilization Program while looking for a way to visualize and track material points within the heart muscle. What they needed were tiny artificial "eggs" containing copper sulfate solution, small enough (about 2 mm in diameter) that they would not injure the heart, and large enough to be seen in Magnetic Resonance Imaging (MRI) images; they also had to be biocompatible and tough enough to withstand the beating of the muscle. The group could not make nor buy sufficient containers. After reading an article on microspheres in NASA Tech Briefs, and a complete set of reports on microencapsulation from the Jet Propulsion Laboratory (JPL), JPL put Antaki in touch with Dr.Taylor Wang of Vanderbilt University who helped construct the myocardial markers. The research is expected to lead to improved understanding of how the heart works and what takes place when it fails.

  6. Artificial Intelligence.

    ERIC Educational Resources Information Center

    Information Technology Quarterly, 1985

    1985-01-01

    This issue of "Information Technology Quarterly" is devoted to the theme of "Artificial Intelligence." It contains two major articles: (1) Artificial Intelligence and Law" (D. Peter O'Neill and George D. Wood); (2) "Artificial Intelligence: A Long and Winding Road" (John J. Simon, Jr.). In addition, it contains two sidebars: (1) "Calculating and…

  7. Exercise performance of chronic heart failure patients in the early period of support by an axial-flow left ventricular assist device as destination therapy.

    PubMed

    Compostella, Leonida; Russo, Nicola; Setzu, Tiziana; Compostella, Caterina; Bellotto, Fabio

    2014-05-01

    Axial-flow left ventricular assist devices (LVADs) are increasingly used as destination therapy in end-stage chronic heart failure (CHF), as they improve survival and quality of life. Their effect on exercise tolerance in the early phase after implantation is still unclear. The aim of this study was to evaluate the effect of LVADs on the exercise capacity of a group of CHF patients within 2 months after initiation of circulatory support. Cardiopulmonary exercise test data were collected for 26 consecutive LVAD-implanted CHF patients within 2 months of initiation of assistance; the reference group consisted of 30 CHF patients not supported by LVAD who were evaluated after an episode of acute heart failure. Both LVAD and reference groups showed poor physical performance; LVAD patients achieved lower workload (LVAD: 36.3 ± 9.0 W, reference: 56.6 ± 18.2 W, P < 0.001) but reached a similar peak oxygen uptake (peak VO2 ; LVAD: 12.5 ± 3.0 mL/kg/min, reference: 13.6 ± 2.9 mL/kg/min, P = ns) and similar percentages of predicted peak VO2 (LVAD: 48.8 ± 13.9%, reference: 54.2 ± 15.3%, P = ns). While the values of the O2 uptake efficiency slope were 12% poorer in LVAD patients than in reference patients (1124.2 ± 226.3 vs. 1280.2 ± 391.1; P = ns), the kinetics of VO2 recovery after exercise were slightly better in LVAD patients (LVAD: 212.5 ± 62.5, reference: 261.1 ± 80.2 sec, P < 0.05). In the first 2 months after initiation of circulatory support, axial-flow LVAD patients are able to sustain a low-intensity workload; though some cardiopulmonary exercise test parameters suggest persistence of a marked physical deconditioning, their cardiorespiratory performance is similar to that of less compromised CHF patients, possibly due to positive hemodynamic effects beginning to be produced by the assist device.

  8. Percutaneous Ventricular Restoration Therapy Using the Parachute Device in Chinese Patients with Ischemic Heart Failure: Three-Month Primary End-point Results of PARACHUTE China Study

    PubMed Central

    Yang, Yue-Jin; Huo, Yong; Xu, Ya-Wei; Wang, Jian-An; Han, Ya-Ling; Ge, Jun-Bo; Zhang, Rui-Yan; Yan, Xiao-Yan; Gao, Run-Lin

    2016-01-01

    Background: The primary cause of ischemic heart failure (HF) is myocardial infarction (MI) resulting in left ventricle (LV) wall motion abnormality secondary to ventricular remodeling. A prospective, nonrandomized study conducted in China was designed to assess safety and efficacy of the percutaneous ventricular restoration therapy using Parachute device (CardioKinetix, Inc., CA, USA) in ischemic HF patients as a result of LV remodeling after anterior wall MI. Methods: Thirty-one patients with New York Heart Association (NYHA) Class II, III ischemic HF, ejection fraction between 15% and 40%, and dilated akinetic or dyskinetic anterior-apical wall without the need to be revascularized were enrolled from seven sites in China from October to December 2014. The Parachute device was implanted through femoral artery. All patients received low-dose aspirin and anticoagulation with warfarin for at least 12 months postdevice implantation. The primary end-point was the assessment of efficacy as measured by the reduction in LV end-systolic volume index (LVESVI) against baseline LVESVI at 3 months postdevice implantation, determined by the echocardiography and measured by echocardiography core laboratory. Quality of life was assessed using EQ-5D and visual analog scale (VAS). For quantitative data comparison, paired t-test (normality data) and signed-rank test (abnormality data) were used; application of signed-rank test was for the ranked data comparison. Results: A change in LVESVI as measured by echocardiography from the preimplant baseline to 3-month postdevice implantation revealed a statistically significant reduction from 77.5 ± 20.0 ml/m2 to 53.1 ± 17.0 ml/m2 (P < 0.0001). The trial met its primary end-point. Of the 31 patients, the procedural success was 96.8%. Overall, NYHA HF class assessment results showed an improvement of more than half a class at 3 months (P < 0.001). Quality of life assessed by the VAS value increased 11.5 points (P < 0.01), demonstrating

  9. 21 CFR 874.3375 - Battery-powered artificial larynx.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3375 Battery-powered artificial larynx. (a) Identification. A battery-powered artificial larynx is an externally applied device... the voicebox, the device generates mechanical vibrations which resonate in the oral and nasal...

  10. 21 CFR 874.3375 - Battery-powered artificial larynx.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3375 Battery-powered artificial larynx. (a) Identification. A battery-powered artificial larynx is an externally applied device... the voicebox, the device generates mechanical vibrations which resonate in the oral and nasal...

  11. Heart transplantation: review

    PubMed Central

    Mangini, Sandrigo; Alves, Bárbara Rubim; Silvestre, Odílson Marcos; Pires, Philippe Vieira; Pires, Lucas José Tachotti; Curiati, Milena Novaes Cardoso; Bacal, Fernando

    2015-01-01

    ABSTRACT Heart transplantation is currently the definitive gold standard surgical approach in the treatment of refractory heart failure. However, the shortage of donors limits the achievement of a greater number of heart transplants, in which the use of mechanical circulatory support devices is increasing. With well-established indications and contraindications, as well as diagnosis and treatment of rejection through defined protocols of immunosuppression, the outcomes of heart transplantation are very favorable. Among early complications that can impact survival are primary graft failure, right ventricular dysfunction, rejection, and infections, whereas late complications include cardiac allograft vasculopathy and neoplasms. Despite the difficulties for heart transplantation, in particular, the shortage of donors and high mortality while on the waiting list, in Brazil, there is a great potential for both increasing effective donors and using circulatory assist devices, which can positively impact the number and outcomes of heart transplants. PMID:26154552

  12. Early trends in N-terminal pro-brain natriuretic peptide values after left ventricular assist device implantation for chronic heart failure.

    PubMed

    Hasin, Tal; Kushwaha, Sudhir S; Lesnick, Timothy G; Kremers, Walter; Boilson, Barry A; Schirger, John A; Clavell, Alfredo L; Rodeheffer, Richard J; Frantz, Robert P; Edwards, Brooks S; Pereira, Naveen L; Stulak, John M; Joyce, Lyle; Daly, Richard; Park, Soon J; Jaffe, Allan S

    2014-10-15

    Left ventricular assist devices (LVADs) acutely decrease left ventricular wall stress. Thus, early postoperative levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) should decrease. This study investigated postoperative changes in NT-proBNP levels, the parameters related to changes, and the possible association with complications by performing a retrospective analysis of changes in daily NT-proBNP (pg/ml) levels from admission to discharge both before and after LVAD implantation in a tertiary referral center. For 72 patients implanted with HeartMate II LVADs, baseline NT-proBNP levels were elevated at 3,943 ng/ml (interquartile range 1,956 to 12,964). Preoperative stabilization led to marked decreases in NT-proBNP. Levels peaked 3 days after surgery and subsequently decreased. Patients with complicated postoperative courses had higher early postoperative elevations. By discharge, NT-proBNP decreased markedly but was still 2.83 (1.60 to 5.76) times the age-based upper limit of normal. The 26% reduction in NT-proBNP between admission and discharge was due mostly to the preoperative reductions and not those induced by the LVAD itself. The decrease was not associated with decreases in LV volume. In conclusion, preoperative treatment reduces NT-proBNP values. The magnitude of early postoperative changes is related to the clinical course. Levels at discharge remain markedly elevated and similar to values after preoperative stabilization despite presumptive acute LV unloading.

  13. Beta-blocker, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, nitrate-hydralazine, diuretics, aldosterone antagonist, ivabradine, devices and digoxin (BANDAID(2) ): an evidence-based mnemonic for the treatment of systolic heart failure.

    PubMed

    Chia, N; Fulcher, J; Keech, A

    2016-06-01

    Heart failure causes significant morbidity and mortality, with recognised underutilisation rates of guideline-based therapies. Our aim was to review current evidence for heart failure treatments and derive a mnemonic summarising best practice, which might assist physicians in patient care. Treatments were identified for review from multinational society guidelines and recent randomised trials, with a primary aim of examining their effects in systolic heart failure patients on mortality, hospitalisation rates and symptoms. Secondary aims were to consider other clinical benefits. MEDLINE and EMBASE were searched using a structured keyword strategy and the retrieved articles were evaluated methodically to produce an optimised reference list for each treatment. We devised the mnemonic BANDAID (2) , standing for beta-blocker, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, nitrate-hydralazine (or potentially neprilysin inhibitor), diuretics, aldosterone antagonist, ivabradine, devices (automatic implantable cardioverter defibrillator, cardiac resynchronisation therapy or both) and digoxin as a representation of treatments with strong evidence for their use in systolic heart failure. Treatment with omega-3 fatty acids, statins or anti-thrombotic therapies has limited benefits in a general heart failure population. Adoption of this mnemonic for current evidence-based treatments for heart failure may help improve prescribing rates and patient outcomes in this debilitating, high mortality condition.

  14. Totally implantable artificial organ: cardiac prosthesis.

    PubMed

    Nosé, Y

    1986-04-01

    This article reviews the current status of completely implantable cardiac prostheses, with an emphasis on those systems presently under development at The Cleveland Clinic Foundation (CCF). Such devices have been one of the final goals of artificial heart research since 1957, when Dr. Kolff initiated these studies in Cleveland. Although earlier plans aimed at using radioisotopes as the energy source, more recently, due to public opinion and sociopolitical influences, the shift has been towards exclusive use of electrically activated energy converters. These systems can be roughly broken down into two groups according to the powertrain configuration. In the first group, electric heating coils maintain liquid salts in thermal batteries at temperatures close to 500 degrees C. This thermal energy is then converted (through a Stirling cycle) to mechanical motion of the pusher plate (PP) which in turn acts on the blood. Two such systems (emphasized in this article) are under development here at CCF in joint efforts with Nimbus Corporation and the University of Washington, respectively. In the second group of ventricular assist systems, electric energy is converted directly to PP motion through rotating cams, solenoids, or electrohydraulic transmission systems. At least four American contractors are working at the preclinical stage on this group of devices. One in particular, the CCF-Nimbus system, consisting of a biolized surface blood pump, an electrohydraulic energy converter, and a compliance chamber to handle the variable volume behind the PP, is described in depth in this discussion. In terms of future prospects, it is forecasted that by 1988, the completely implantable VAS will be used clinically, and that by 1994, a specially designed total artificial heart (nontethered patient) would be ready for human use. PMID:3718273

  15. [Two approaches to correction of disturbed hemostasis in patients with mechanical artificial heart valves at the long-term follow-up].

    PubMed

    Orlovskiĭ, P I; Gritsenko, V V; Vavilova, T V; Kadinskaia, M I; Petrishina, T I; Mochalov, O Iu; Polezhaev, D A; Galileeva, A N

    2004-01-01

    The investigation of the hemostasis system performed in 47 patients with mechanical heart valves (MHV) at the terms of (3.50 +/- 0.25) years included 30 men and 17 women. There were 24 cases of aortal MHV and 23 cases of mitral MHV, I-II functional class (NYHA). The patients were given oral anticoagulants: phenylin to 35 patients (0.009 mg/day), varfarin to 12 patients (52.6 mg/a week). The primary examination of the patients has revealed insufficient anticoagulation protection and clinically asymptomatic permanent intravascular coagulation of the third degree (PIC-3), with the signs of activation of thrombocytic and/or coagulation link of hemostasis. It has been found that a complex assessment of the hemostasis system state including the vascular-thrombocytic link is an obligatory condition of the right choice and timely correction of the PIC-3 in patients with MHV. The methods of correction of impaired hemostasis depend on the primary involvement of the vascular-thrombocytic and/or coagulation link of hemostasis. The pathogenetically selected antithrombotic therapy for patients with MHV allows timely arrest of PIC-3 and less risk of the development of thrombosis and thrombo-embolic complications at long-term periods of observation. PMID:15651689

  16. The European artificial organ scene: present status.

    PubMed

    Vanholder, Raymond; del Cañizo, Juan F; Sauer, Igor M; Stegmayr, Bernd

    2005-06-01

    This article summarizes the current evolutions regarding artificial organs in Europe. The review emanates from the activities by four of the work groups of the European Society for Artificial Organs (ESAO) and is essentially based on the reports by these work groups at the latest ESAO meeting in Warsaw, Poland (2004). The topics are: apheresis, heart support, liver support, uremic toxins.

  17. Continuous flow left ventricular assist device implantation concomitant with aortic arch replacement and aortic valve closure in a patient with end-stage heart failure associated with bicuspid aortic valve.

    PubMed

    Akiyama, Masatoshi; Hosoyama, Katsuhiro; Kumagai, Kiichiro; Kawamoto, Shunsuke; Saiki, Yoshikatsu

    2015-12-01

    Left ventricular assist device (LVAD) implantation has become an established treatment for patients with end-stage heart failure as a bridge to cardiac transplantation. During LVAD implantation, some patients require concomitant surgeries, including tricuspid valve repair, aortic valve repair or replacement, and patent foramen ovale closure. However, concomitant aortic surgeries are rare in patients requiring LVAD implantation. We successfully performed total arch replacement with an open distal technique, aortic valve closure, and continuous flow LVAD implantation simultaneously. PMID:25957796

  18. Artificial intelligence

    SciTech Connect

    Firschein, O.

    1984-01-01

    This book presents papers on artificial intelligence. Topics considered include knowledge engineering, expert systems, applications of artificial intelligence to scientific reasoning, planning and problem solving, error recovery in robots through failure reason analysis, programming languages, natural language, speech recognition, map-guided interpretation of remotely-sensed imagery, and image understanding architectures.

  19. Artificial Intelligence.

    ERIC Educational Resources Information Center

    Thornburg, David D.

    1986-01-01

    Overview of the artificial intelligence (AI) field provides a definition; discusses past research and areas of future research; describes the design, functions, and capabilities of expert systems and the "Turing Test" for machine intelligence; and lists additional sources for information on artificial intelligence. Languages of AI are also briefly…

  20. Wireless Solar Water Splitting Device with Robust Cobalt-Catalyzed, Dual-Doped BiVO4 Photoanode and Perovskite Solar Cell in Tandem: A Dual Absorber Artificial Leaf.

    PubMed

    Kim, Jin Hyun; Jo, Yimhyun; Kim, Ju Hun; Jang, Ji Wook; Kang, Hyun Jun; Lee, Young Hye; Kim, Dong Suk; Jun, Yongseok; Lee, Jae Sung

    2015-12-22

    A stand-alone, wireless solar water splitting device without external energy supply has been realized by combining in tandem a CH3NH3PbI3 perovskite single junction solar cell with a cobalt carbonate (Co-Ci)-catalyzed, extrinsic/intrinsic dual-doped BiVO4 (hydrogen-treated and 3 at% Mo-doped). The photoanode recorded one of the highest photoelectrochemical water oxidation activity (4.8 mA/cm(2) at 1.23 VRHE) under simulated 1 sun illumination. The oxygen evolution Co-Ci co-catalyst showed similar performance to best known cobalt phosphate (Co-Pi) (5.0 mA/cm(2) at 1.23 VRHE) on the same dual-doped BiVO4 photoanode, but with significantly better stability. A tandem artificial-leaf-type device produced stoichiometric hydrogen and oxygen with an average solar-to-hydrogen efficiency of 4.3% (wired), 3.0% (wireless) under simulated 1 sun illumination. Hence, our device based on a D4 tandem photoelectrochemical cell represents a meaningful advancement in performance and cost over the device based on a triple-junction solar cell-electrocatalyst combination.

  1. The hemodynamic effect of phase differences between the BJUT-II ventricular assist device and native heart on the cardiovascular system.

    PubMed

    Gu, Kaiyun; Gao, Bin; Chang, Yu; Zeng, Yi

    2014-11-01

    The BJUT-II VAD (which was previously called the intra-aorta pump) is a novel left ventricular assist device (LVAD) with a special structure and connection with the native heart. The hemodynamic effect of the phase difference of this pump on the cardiovascular system is still unclear. In this work, seven speed waveforms, whose phase differences vary from 0° to 180°, are used to evaluate the hemodynamic effect of change in phase difference on the cardiovascular system. The external work (EW), equivalent afterload (EAL), pulsatile ratio (PR), and mean aortic pressure during diastolic period (MAPD) are chosen to evaluate the hemodynamic state of the circulatory system. Mathematical study results show that the support levels generated by the BJUT-II VAD under various phase differences are comparable. In contrast, EW, EAL, PR, and MAPD are significantly affected by change in phase difference. It is found that EW reaches its maximum value when the phase difference equals 30°. Similarly, EAL declines with increasing phase difference. PR reaches its maximum value when the phase difference is at 60°. In addition, MAPD decreases with increasing phase difference and then achieves its maximum value at 30°. To obtain comprehensive evaluation of the hemodynamic effects of phase difference on the cardiovascular system, a weight detection algorithm (WDA) whose output indicates the hemodynamic state of the circulatory system is also designed, with EW, PR, and MAPD chosen as the inputs. The minimum value of the output of the WDA indicates the optimal hemodynamic state and optimal phase difference for the BJUT-II VAD. According to the output of the WDA, 30° is considered to be the optimal phase difference for the BJUT-II VAD.

  2. Investigation of Bioinspired Gecko Fibers to Improve Adhesion of HeartLander Surgical Robot

    PubMed Central

    Tortora, Giuseppe; Glass, Paul; Wood, Nathan; Aksak, Burak; Menciassi, Arianna; Sitti, Metin; Riviere, Cameron

    2012-01-01

    In this paper, a way for improving adhesion of a mobile robot (HeartLander) on biological tissue is presented, that integrates bioinspired gecko adhesive fibers on the robot surface. HeartLander is a medical robot proposed to perform clinical procedures on a beating heart, overcoming limitations of current cardiac procedures. Biologically inspired gecko fibers have been proposed for adhesion on surfaces. The aim of this work is to assess the advantages of integrating these structures for enhancing the grip between the artificial device and the myocardial tissue. Experimental in vitro tests have been carried out assessing the performance of the HeartLander attached to muscular tissue. The effect of the adhesive fibers on improving the adhesion behavior on a slippery surface has been investigated, obtaining a friction increase of 57.3 %. PMID:23366040

  3. Artificial intelligence in nanotechnology.

    PubMed

    Sacha, G M; Varona, P

    2013-11-15

    During the last decade there has been increasing use of artificial intelligence tools in nanotechnology research. In this paper we review some of these efforts in the context of interpreting scanning probe microscopy, the study of biological nanosystems, the classification of material properties at the nanoscale, theoretical approaches and simulations in nanoscience, and generally in the design of nanodevices. Current trends and future perspectives in the development of nanocomputing hardware that can boost artificial-intelligence-based applications are also discussed. Convergence between artificial intelligence and nanotechnology can shape the path for many technological developments in the field of information sciences that will rely on new computer architectures and data representations, hybrid technologies that use biological entities and nanotechnological devices, bioengineering, neuroscience and a large variety of related disciplines.

  4. Artificial vision workbench.

    PubMed

    Frenger, P

    1997-01-01

    Machine vision is an important component of medical systems engineering. Inexpensive miniature solid state cameras are now available. This paper describes how these devices can be used as artificial retinas, to take snapshots and moving pictures in monochrome or color. Used in pairs, they produce a stereoscopic field of vision and enable depth perception. Macular and peripheral vision can be simulated electronically. This paper also presents the author's design of an artificial orbit for this synthetic eye. The orbit supports the eye, protects it, and provides attachment points for the ocular motion control system. Convergence and image fusion can be produced, and saccades simulated, along with the other ocular motions. The use of lenses, filters, irises and focusing mechanisms are also discussed. Typical camera-computer interfaces are described, including the use of "frame grabbers" and analog-to-digital image conversion. Software programs for eye positioning, image manipulation, feature extraction and object recognition are discussed, including the application of artificial neural networks.

  5. Artificial intelligence in nanotechnology

    NASA Astrophysics Data System (ADS)

    Sacha, G. M.; Varona, P.

    2013-11-01

    During the last decade there has been increasing use of artificial intelligence tools in nanotechnology research. In this paper we review some of these efforts in the context of interpreting scanning probe microscopy, the study of biological nanosystems, the classification of material properties at the nanoscale, theoretical approaches and simulations in nanoscience, and generally in the design of nanodevices. Current trends and future perspectives in the development of nanocomputing hardware that can boost artificial-intelligence-based applications are also discussed. Convergence between artificial intelligence and nanotechnology can shape the path for many technological developments in the field of information sciences that will rely on new computer architectures and data representations, hybrid technologies that use biological entities and nanotechnological devices, bioengineering, neuroscience and a large variety of related disciplines.

  6. 21 CFR 870.3945 - Prosthetic heart valve sizer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Prosthetic heart valve sizer. 870.3945 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3945 Prosthetic heart valve sizer. (a) Identification. A prosthetic heart valve sizer is a device used to measure the size of...

  7. 21 CFR 870.3945 - Prosthetic heart valve sizer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Prosthetic heart valve sizer. 870.3945 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3945 Prosthetic heart valve sizer. (a) Identification. A prosthetic heart valve sizer is a device used to measure the size of...

  8. 21 CFR 870.3925 - Replacement heart valve.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Replacement heart valve. 870.3925 Section 870.3925...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3925 Replacement heart valve. (a) Identification. A replacement heart valve is a device intended to perform the function of...

  9. 21 CFR 870.3945 - Prosthetic heart valve sizer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Prosthetic heart valve sizer. 870.3945 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3945 Prosthetic heart valve sizer. (a) Identification. A prosthetic heart valve sizer is a device used to measure the size of...

  10. 21 CFR 870.3925 - Replacement heart valve.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Replacement heart valve. 870.3925 Section 870.3925...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3925 Replacement heart valve. (a) Identification. A replacement heart valve is a device intended to perform the function of...

  11. 21 CFR 870.3945 - Prosthetic heart valve sizer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Prosthetic heart valve sizer. 870.3945 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3945 Prosthetic heart valve sizer. (a) Identification. A prosthetic heart valve sizer is a device used to measure the size of...

  12. 21 CFR 870.3945 - Prosthetic heart valve sizer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Prosthetic heart valve sizer. 870.3945 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3945 Prosthetic heart valve sizer. (a) Identification. A prosthetic heart valve sizer is a device used to measure the size of...

  13. 21 CFR 870.3925 - Replacement heart valve.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Replacement heart valve. 870.3925 Section 870.3925...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3925 Replacement heart valve. (a) Identification. A replacement heart valve is a device intended to perform the function of...

  14. 2015 SCAI/ACC/HFSA/STS Clinical Expert Consensus Statement on the Use of Percutaneous Mechanical Circulatory Support Devices in Cardiovascular Care: Endorsed by the American Heart Assocation, the Cardiological Society of India, and Sociedad Latino Americana de Cardiologia Intervencion; Affirmation of Value by the Canadian Association of Interventional Cardiology-Association Canadienne de Cardiologie d'intervention.

    PubMed

    Rihal, Charanjit S; Naidu, Srihari S; Givertz, Michael M; Szeto, Wilson Y; Burke, James A; Kapur, Navin K; Kern, Morton; Garratt, Kirk N; Goldstein, James A; Dimas, Vivian; Tu, Thomas

    2015-05-19

    Although historically the intra-aortic balloon pump has been the only mechanical circulatory support device available to clinicians, a number of new devices have become commercially available and have entered clinical practice. These include axial flow pumps, such as Impella(®); left atrial to femoral artery bypass pumps, specifically the TandemHeart; and new devices for institution of extracorporeal membrane oxygenation. These devices differ significantly in their hemodynamic effects, insertion, monitoring, and clinical applicability. This document reviews the physiologic impact on the circulation of these devices and their use in specific clinical situations. These situations include patients undergoing high-risk percutaneous coronary intervention, those presenting with cardiogenic shock, and acute decompensated heart failure. Specialized uses for right-sided support and in pediatric populations are discussed and the clinical utility of mechanical circulatory support devices is reviewed, as are the American College of Cardiology/American Heart Association clinical practice guidelines.

  15. 2015 SCAI/ACC/HFSA/STS Clinical Expert Consensus Statement on the Use of Percutaneous Mechanical Circulatory Support Devices in Cardiovascular Care (Endorsed by the American Heart Association, the Cardiological Society of India, and Sociedad Latino Americana de Cardiologia Intervencion; Affirmation of Value by the Canadian Association of Interventional Cardiology-Association Canadienne de Cardiologie D'intervention).

    PubMed

    Rihal, Charanjit S; Naidu, Srihari S; Givertz, Michael M; Szeto, Wilson Y; Burke, James A; Kapur, Navin K; Kern, Morton; Garratt, Kirk N; Goldstein, James A; Dimas, Vivian; Tu, Thomas

    2015-06-01

    Although historically the intra-aortic balloon pump has been the only mechanical circulatory support device available to clinicians, a number of new devices have become commercially available and have entered clinical practice. These include axial flow pumps, such as Impella®; left atrial to femoral artery bypass pumps, specifically the TandemHeart; and new devices for institution of extracorporeal membrane oxygenation. These devices differ significantly in their hemodynamic effects, insertion, monitoring, and clinical applicability. This document reviews the physiologic impact on the circulation of these devices and their use in specific clinical situations. These situations include patients undergoing high-risk percutaneous coronary intervention, those presenting with cardiogenic shock, and acute decompensated heart failure. Specialized uses for right-sided support and in pediatric populations are discussed and the clinical utility of mechanical circulatory support devices is reviewed, as are the American College of Cardiology/American Heart Association clinical practice guidelines.

  16. 2015 SCAI/ACC/HFSA/STS Clinical Expert Consensus Statement on the Use of Percutaneous Mechanical Circulatory Support Devices in Cardiovascular Care (Endorsed by the American Heart Association, the Cardiological Society of India, and Sociedad Latino Americana de Cardiologia Intervencion; Affirmation of Value by the Canadian Association of Interventional Cardiology-Association Canadienne de Cardiologie d'intervention).

    PubMed

    Rihal, Charanjit S; Naidu, Srihari S; Givertz, Michael M; Szeto, Wilson Y; Burke, James A; Kapur, Navin K; Kern, Morton; Garratt, Kirk N; Goldstein, James A; Dimas, Vivian; Tu, Thomas

    2015-06-01

    Although historically the intra-aortic balloon pump has been the only mechanical circulatory support device available to clinicians, a number of new devices have become commercially available and have entered clinical practice. These include axial flow pumps, such as Impella(®); left atrial to femoral artery bypass pumps, specifically the TandemHeart; and new devices for institution of extracorporeal membrane oxygenation. These devices differ significantly in their hemodynamic effects, insertion, monitoring, and clinical applicability. This document reviews the physiologic impact on the circulation of these devices and their use in specific clinical situations. These situations include patients undergoing high-risk percutaneous coronary intervention, those presenting with cardiogenic shock, and acute decompensated heart failure. Specialized uses for right-sided support and in pediatric populations are discussed and the clinical utility of mechanical circulatory support devices is reviewed, as are the American College of Cardiology/American Heart Association clinical practice guidelines.

  17. Science and Technology of Bio-Inert Thin Films as Hermetic-Encapsulating Coatings for Implantable Biomedical Devices: Application to Implantable Microchip in the Eye for the Artificial Retina

    NASA Astrophysics Data System (ADS)

    Auciello, Orlando; Shi, Bing

    Extensive research has been devoted to the development of neuron prostheses and hybrid bionic systems to establish links between the nervous system and electronic or robotic prostheses with the main focus of restoring motor and sensory functions in blind patients. Artificial retinas, one type of neural prostheses we are currently working on, aim to restore some vision in blind patients caused by retinitis picmentosa or macular degeneration, and in the future to restore vision at the level of face recognition, if not more. Currently there is no hermetic microchip-size coating that provides a reliable, long-term (years) performance as encapsulating coating for the artificial retina Si microchip to be implanted inside the eye. This chapter focuses on the critical topics relevant to the development of a robust, long-term artificial retina device, namely the science and technology of hermetic bio-inert encapsulating coatings to protect a Si microchip implanted in the human eye from being attacked by chemicals existing in the eye's saline environment. The work discussed in this chapter is related to the development of a novel ultrananocrystalline diamond (UNCD) hermetic coating, which exhibited no degradation in rabbit eyes. The material synthesis, characterization, and electrochemical properties of these hermetic coatings are reviewed for application as encapsulating coating for the artificial retinal microchips implantable inside the human eye. Our work has shown that UNCD coatings may provide a reliable hermetic bio-inert coating technology for encapsulation of Si microchips implantable in the eye specifically and in the human body in general. Electrochemical tests of the UNCD films grown under CH4/Ar/H2 (1%) plasma exhibit the lowest leakage currents (˜7 × 10-7 A/cm2) in a saline solution simulating the eye environment. This leakage is incompatible with the functionality of the first-generation artificial retinal microchip. However, the growth of UNCD on top of the

  18. Using the Virtual Heart Model to validate the mode-switch pacemaker operation.

    PubMed

    Jiang, Zhihao; Connolly, Allison; Mangharam, Rahul

    2010-01-01

    Artificial pacemakers are one of the most widely-used implantable devices today, with millions implanted worldwide. The main purpose of an artificial pacemaker is to treat bradycardia, or slow heart beats, by pacing the atrium and ventricles at a faster rate. While the basic functionality of the device is fairly simple, there are many documented cases of death and injury due to device malfunctions. The frequency of malfunctions due to firmware problems will only increase as the pacemaker operations become more complex in an attempt to expand the use of the device. One reason these malfunctions arise is that there is currently no methodology for formal validation and verification of medical device software, as there are in the safety-critical domains of avionics and industrial control automation. We have developed a timed-automata based Virtual Heart Model (VHM) to act as platform for medical device software validation and verification. Through a case study involving multiple arrhythmias, this investigation shows how the VHM can be used with closed-loop operation of a pacemaker to validate the necessity and functionality of the complex mode-switch pacemaker operation. We demonstrate the correct pacemaker operation, to switch from one rhythm management mode to another, in patients with supraventricular tachycardias. (1).

  19. Heart Pump Design for Cleveland Clinic Foundation

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Through a Lewis CommTech Program project with the Cleveland Clinic Foundation, the NASA Lewis Research Center is playing a key role in the design and development of a permanently implantable, artificial heart pump assist device. Known as the Innovative Ventricular Assist System (IVAS), this device will take on the pumping role of the damaged left ventricle of the heart. The key part of the IVAS is a nonpulsatile (continuous flow) artificial heart pump with centrifugal impeller blades, driven by an electric motor. Lewis is part of an industry and academia team, led by the Ohio Aerospace Institute (OAI), that is working with the Cleveland Clinic Foundation to make IVAS a reality. This device has the potential to save tens of thousands of lives each year, since 80 percent of heart attack victims suffer irreversible damage to the left ventricle, the part of the heart that does most of the pumping. Impeller blade design codes and flow-modeling analytical codes will be used in the project. These codes were developed at Lewis for the aerospace industry but will be applicable to the IVAS design project. The analytical codes, which currently simulate the flow through the compressor and pump systems, will be used to simulate the flow within the blood pump in the artificial heart assist device. The Interdisciplinary Technology Office heads up Lewis' efforts in the IVAS project. With the aid of numerical modeling, the blood pump will address many design issues, including some fluid-dynamic design considerations that are unique to the properties of blood. Some of the issues that will be addressed in the design process include hemolysis, deposition, recirculation, pump efficiency, rotor thrust balance, and bearing lubrication. Optimum pumping system performance will be achieved by modeling all the interactions between the pump components. The interactions can be multidisciplinary and, therefore, are influenced not only by the fluid dynamics of adjacent components but also by

  20. Artificial and Bioartificial Liver Support

    PubMed Central

    2007-01-01

    The fact that liver failure constitutes a life-threatening condition and can, in most cases, only be overcome by orthotopic liver transplantation, lead to the development of various artificial and bioartificial liver support devices. While artificial systems are based on the principles of adsorption and filtration, the more complex concept of bioartificial devices includes the provision of liver cells. Instead of solely focussing on detoxification, these concepts also support the failing organ concerning synthetic and regulative functions. The systems were evaluated in a variety of clinical studies, demonstrating their safety and investigating the impact on the patient's clinical condition. This review gives an overview over the most common artificial and bioartificial liver support devices and summarizes the results of the clinical studies. PMID:19279696

  1. What to Expect Before a Heart Transplant

    MedlinePlus

    ... Cardiac Rehabilitation Heart Failure Heart Surgery Implantable Cardioverter Defibrillators Ventricular Assist Device Send a link to NHLBI ... at the transplant centers may place implantable cardioverter defibrillators (ICDs) in patients before surgery. ICDs are small ...

  2. [Current state and development of artificial lungs].

    PubMed

    Mei, Zaoxian; Sun, Xin; Wu, Qi

    2010-12-01

    The artificial lung is a technical device for providing life support; it will be put in use when the natural lungs are failing and are not able to maintain sufficient oxygenation of the body's organ systems. From the viewpoint of long-term development, the artificial lung should be permanently implanted in the body, so that it will substitute for the human pulmonary function partially or completely. In this paper, four artificial lung technologies were expounded with reference to the development and research process of artificial lung. They were extracorporeal membrane oxygenation, intravascular artificial lung, implantable artificial lung, and pumpless extracorporeal lung assist. In this paper were described the structure of the four kinds of artificial lung, the working principle, and their advantages, disadvantages and indications. The prospect of artificial lung was evaluated in the light of the data from the existing animal experiments and from the clinical experience of the centers.

  3. Heart Attack

    MedlinePlus

    ... attack treatment works best when it's given right after symptoms occur. Prompt treatment of a heart attack can help prevent or limit damage to the heart and prevent sudden death. Call 9-1-1 Right Away A heart ...

  4. Heart Anatomy

    MedlinePlus

    ... Incredible Machine Bonus poster (PDF) The Human Heart Anatomy Blood The Conduction System The Coronary Arteries The ... of the Leg Vasculature of the Torso Heart anatomy illustrations and animations for grades K-6. Heart ...

  5. Heart attack

    MedlinePlus

    ... infarction; Non-ST - elevation myocardial infarction; NSTEMI; CAD - heart attack; Coronary artery disease - heart attack ... made up of cholesterol and other cells. A heart attack may occur when: A tear in the ...

  6. Heart murmurs

    MedlinePlus

    Chest sounds - murmurs; Heart sounds - abnormal; Murmur - innocent; Innocent murmur; Systolic heart murmur; Diastolic heart murmur ... classified ("graded") depending on how loud the murmur sounds with a stethoscope. The grading is on a ...

  7. Heart Block

    MedlinePlus

    ... Block Explore Heart Block What Is... Electrical System & EKG Results Types Causes Who Is at Risk Signs & ... heart block. Doctors use a test called an EKG (electrocardiogram) to help diagnose heart block. This test ...

  8. A localizing circumferential compression device delayed death after artificial eastern diamondback rattlesnake envenomation to the torso of an animal model in a pilot study.

    PubMed

    Hack, Jason B; Orogbemi, Babatunde; Deguzman, Jocelyn M; Brewer, Kori L; Meggs, William J; O'Rourke, Dorcas

    2010-06-01

    Nearly all prior studies to delay onset of systemic toxicity and death after snake bite use a model of distal extremity envenomation. In the first of a series of planned studies using snake venoms with different toxicity profiles, the application of a novel device in a new model of torso envenomation in the setting of Eastern Coral Snake (Micrurus fulvius) venom (a potent neurotoxin) envenomation showed promise by delaying systemic intoxication. In this pilot study, we investigated this novel localizing circumferential compression (LoCC) device's ability to delay onset of life threatening systemic toxicity after Eastern Diamondback Rattlesnake (Crotalus adamanteus) envenomation, a potent hemotoxic and myotoxic venom. With university approval, four juvenile female pigs (22-25 kg) were anesthetized, sedated, and intubated but not paralyzed to allow for spontaneous respirations. Each animal was injected subcutaneously with 50 mg of C. adamanteus venom in identical preselected areas of the trunk. After 1 min, two treatment animals had the LoCC device applied; two control animals had no intervention. Vital signs were recorded every 10 min for the first 2 h and every 30 min thereafter. Endpoints included cardiovascular collapse (fatal arrhythmia, loss of mean arterial pressure, or pulse) or respiratory arrest (<3 breaths/min, saturation < 80%) or survival to 7 h. The pigs in the treatment group reached an endpoint at an average time of 355 (+/-65) min compared with control 32 (+/-3.5) min (p < 0.04). In this pilot study, the LoCC device significantly delayed onset of systemic symptoms and death after torso envenomation with Eastern Diamondback Rattlesnake venom in this model.

  9. 21 CFR 870.3935 - Prosthetic heart valve holder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Prosthetic heart valve holder. 870.3935 Section... heart valve holder. (a) Identification. A prosthetic heart valve holder is a device used to hold a replacement heart valve while it is being sutured into place. (b) Classification. Class I. The device...

  10. 21 CFR 870.3935 - Prosthetic heart valve holder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Prosthetic heart valve holder. 870.3935 Section... heart valve holder. (a) Identification. A prosthetic heart valve holder is a device used to hold a replacement heart valve while it is being sutured into place. (b) Classification. Class I. The device...

  11. 21 CFR 870.3935 - Prosthetic heart valve holder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Prosthetic heart valve holder. 870.3935 Section... heart valve holder. (a) Identification. A prosthetic heart valve holder is a device used to hold a replacement heart valve while it is being sutured into place. (b) Classification. Class I. The device...

  12. 21 CFR 870.3935 - Prosthetic heart valve holder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Prosthetic heart valve holder. 870.3935 Section... heart valve holder. (a) Identification. A prosthetic heart valve holder is a device used to hold a replacement heart valve while it is being sutured into place. (b) Classification. Class I. The device...

  13. 21 CFR 870.3935 - Prosthetic heart valve holder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Prosthetic heart valve holder. 870.3935 Section... heart valve holder. (a) Identification. A prosthetic heart valve holder is a device used to hold a replacement heart valve while it is being sutured into place. (b) Classification. Class I. The device...

  14. Terahertz Artificial Dielectric Lens

    NASA Astrophysics Data System (ADS)

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M.

    2016-03-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices.

  15. Terahertz Artificial Dielectric Lens.

    PubMed

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M

    2016-01-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices. PMID:26973294

  16. Terahertz Artificial Dielectric Lens.

    PubMed

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M

    2016-03-14

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices.

  17. Terahertz Artificial Dielectric Lens

    PubMed Central

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M.

    2016-01-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices. PMID:26973294

  18. Left Ventricular Assist Device Implantation After Intracardiac Parachute Device Removal.

    PubMed

    Abu Saleh, Walid K; Al Jabbari, Odeaa; Bruckner, Brian A; Suarez, Erik E; Estep, Jerry D; Loebe, Matthias

    2015-08-01

    Left ventricular assist device implantation is a proven and efficient modality for the treatment of end-stage heart failure. Left ventricular assist device versatility as a bridge to heart transplantation or destination therapy has led to improved patient outcomes with a concomitant rise in its overall use. Other less invasive treatment modalities are being developed to improve heart function and morbidity and mortality for the heart failure population. Percutaneous ventricular restoration is a new investigational therapy that deploys an intracardiac parachute to wall off damaged myocardium in patients with dilated left ventricles and ischemic heart failure. Clinical trials are under way to test the efficacy of percutaneous ventricular restoration using the parachute device. This review describes our encounter with the parachute device, its explantation due to refractory heart failure, and surgical replacement with a left ventricular assist device. PMID:26234850

  19. Left Ventricular Assist Device Implantation After Intracardiac Parachute Device Removal.

    PubMed

    Abu Saleh, Walid K; Al Jabbari, Odeaa; Bruckner, Brian A; Suarez, Erik E; Estep, Jerry D; Loebe, Matthias

    2015-08-01

    Left ventricular assist device implantation is a proven and efficient modality for the treatment of end-stage heart failure. Left ventricular assist device versatility as a bridge to heart transplantation or destination therapy has led to improved patient outcomes with a concomitant rise in its overall use. Other less invasive treatment modalities are being developed to improve heart function and morbidity and mortality for the heart failure population. Percutaneous ventricular restoration is a new investigational therapy that deploys an intracardiac parachute to wall off damaged myocardium in patients with dilated left ventricles and ischemic heart failure. Clinical trials are under way to test the efficacy of percutaneous ventricular restoration using the parachute device. This review describes our encounter with the parachute device, its explantation due to refractory heart failure, and surgical replacement with a left ventricular assist device.

  20. Artificial rearing.

    PubMed

    Dominguez, Hector D; Thomas, Jennifer D

    2008-01-01

    Prenatal alcohol exposure disrupts development, leading to a range of effects referred to as fetal alcohol spectrum disorders (FASD). FASDs include physical, central nervous system, and behavioral alterations. Animal model systems are used to study the relationship between alcohol-related central nervous system damage and behavioral alterations, risk factors for FASD, mechanisms of alcohol-induced damage, as well as treatments and interventions. When using a rodent model, it is important to recognize that the timing of brain development relative to birth differs between humans and rodents. Thus, to model alcohol exposure during the third trimester equivalent, rats must be exposed during early postnatal development (postnatal days 4-9). Artificial rearing is one experimental paradigm that is used to expose neonatal rats to alcohol during this period of brain development. Neonatal rat pups are housed in an artificial rearing environment and automatically fed a milk diet substitute via an intragastric cannula to ensure adequate growth during the treatment period. Alcohol is delivered in the milk diet. This chapter provides a description of the methods needed for this administrative technique, including preparation of the artificial rearing environment, gastrostomy surgery, and care of artificially reared rat pups.

  1. Artificial Intelligence.

    ERIC Educational Resources Information Center

    Wash, Darrel Patrick

    1989-01-01

    Making a machine seem intelligent is not easy. As a consequence, demand has been rising for computer professionals skilled in artificial intelligence and is likely to continue to go up. These workers develop expert systems and solve the mysteries of machine vision, natural language processing, and neural networks. (Editor)

  2. Heart Transplantation

    MedlinePlus

    A heart transplant removes a damaged or diseased heart and replaces it with a healthy one. The healthy heart comes from a donor who has died. It is the last resort for people with heart failure when all other treatments have failed. The ...

  3. Heart Diseases

    MedlinePlus

    ... re like most people, you think that heart disease is a problem for others. But heart disease is the number one killer in the U.S. ... disability. There are many different forms of heart disease. The most common cause of heart disease is ...

  4. 21 CFR 870.2860 - Heart sound transducer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Heart sound transducer. 870.2860 Section 870.2860...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2860 Heart sound transducer. (a) Identification. A heart sound transducer is an external transducer that exhibits a change...

  5. 21 CFR 870.2860 - Heart sound transducer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Heart sound transducer. 870.2860 Section 870.2860...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2860 Heart sound transducer. (a) Identification. A heart sound transducer is an external transducer that exhibits a change...

  6. 21 CFR 870.2860 - Heart sound transducer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Heart sound transducer. 870.2860 Section 870.2860...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2860 Heart sound transducer. (a) Identification. A heart sound transducer is an external transducer that exhibits a change...

  7. 21 CFR 870.2860 - Heart sound transducer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Heart sound transducer. 870.2860 Section 870.2860...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2860 Heart sound transducer. (a) Identification. A heart sound transducer is an external transducer that exhibits a change...

  8. Clinical trial design and rationale of the Multicenter Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy With HeartMate 3 (MOMENTUM 3) investigational device exemption clinical study protocol.

    PubMed

    Heatley, Gerald; Sood, Poornima; Goldstein, Daniel; Uriel, Nir; Cleveland, Joseph; Middlebrook, Don; Mehra, Mandeep R

    2016-04-01

    The HeartMate 3 left ventricular assist system (LVAS; St. Jude Medical, Inc., formerly Thoratec Corporation, Pleasanton, CA) was recently introduced into clinical trials for durable circulatory support in patients with medically refractory advanced-stage heart failure. This centrifugal, fully magnetically levitated, continuous-flow pump is engineered with the intent to enhance hemocompatibility and reduce shear stress on blood elements, while also possessing intrinsic pulsatility. Although bridge-to-transplant (BTT) and destination therapy (DT) are established dichotomous indications for durable left ventricular assist device (LVAD) support, clinical practice has challenged the appropriateness of these designations. The introduction of novel LVAD technology allows for the development of clinical trial designs to keep pace with current practices. The prospective, randomized Multicenter Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy With HeartMate 3 (MOMENTUM 3) clinical trial aims to evaluate the safety and effectiveness of the HeartMate 3 LVAS by demonstrating non-inferiority to the HeartMate II LVAS (also St. Jude Medical, Inc.). The innovative trial design includes patients enrolled under a single inclusion and exclusion criteria , regardless of the intended use of the device, with outcomes ascertained in the short term (ST, at 6 months) and long term (LT, at 2 years). This adaptive trial design includes a pre-specified safety phase (n = 30) analysis. The ST cohort includes the first 294 patients and the LT cohort includes the first 366 patients for evaluation of the composite primary end-point of survival to transplant, recovery or LVAD support free of debilitating stroke (modified Rankin score >3), or re-operation to replace the pump. As part of the adaptive design, an analysis by an independent statistician will determine whether sample size adjustment is required at pre-specified times during the study. A further 662

  9. Clinical trial design and rationale of the Multicenter Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy With HeartMate 3 (MOMENTUM 3) investigational device exemption clinical study protocol.

    PubMed

    Heatley, Gerald; Sood, Poornima; Goldstein, Daniel; Uriel, Nir; Cleveland, Joseph; Middlebrook, Don; Mehra, Mandeep R

    2016-04-01

    The HeartMate 3 left ventricular assist system (LVAS; St. Jude Medical, Inc., formerly Thoratec Corporation, Pleasanton, CA) was recently introduced into clinical trials for durable circulatory support in patients with medically refractory advanced-stage heart failure. This centrifugal, fully magnetically levitated, continuous-flow pump is engineered with the intent to enhance hemocompatibility and reduce shear stress on blood elements, while also possessing intrinsic pulsatility. Although bridge-to-transplant (BTT) and destination therapy (DT) are established dichotomous indications for durable left ventricular assist device (LVAD) support, clinical practice has challenged the appropriateness of these designations. The introduction of novel LVAD technology allows for the development of clinical trial designs to keep pace with current practices. The prospective, randomized Multicenter Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy With HeartMate 3 (MOMENTUM 3) clinical trial aims to evaluate the safety and effectiveness of the HeartMate 3 LVAS by demonstrating non-inferiority to the HeartMate II LVAS (also St. Jude Medical, Inc.). The innovative trial design includes patients enrolled under a single inclusion and exclusion criteria , regardless of the intended use of the device, with outcomes ascertained in the short term (ST, at 6 months) and long term (LT, at 2 years). This adaptive trial design includes a pre-specified safety phase (n = 30) analysis. The ST cohort includes the first 294 patients and the LT cohort includes the first 366 patients for evaluation of the composite primary end-point of survival to transplant, recovery or LVAD support free of debilitating stroke (modified Rankin score >3), or re-operation to replace the pump. As part of the adaptive design, an analysis by an independent statistician will determine whether sample size adjustment is required at pre-specified times during the study. A further 662

  10. A Case Series of Biventricular Circulatory Support Using Two Ventricular Assist Devices: A Novel Operative Approach.

    PubMed

    Cork, David P; Tran, Hao A; Silva, Jorge; Barnard, Denise; Greenberg, Barry; Adler, Eric D; Pretorius, Victor

    2015-10-01

    Increased use of continuous-flow left ventricular assist devices (LVADs) to treat advanced heart failure has heightened concern for right ventricular failure after LVAD implantation, which is associated with increased morbidity and mortality. Biventricular support is required in up to 30% of LVAD recipients. Currently, no durable long-term right ventricular assist device (RVAD) has been approved other than the Syncardia (Tucson, AZ) total artificial heart. A recent publication reported the placement of continuous flow LVAD in the heavily trabeculated right ventricle; however, this orientation may jeopardize both assist device and right ventricle function. We describe three cases of right-sided mechanical circulatory support with durable RVAD implanted in the right atrium, allowing long-term support with fewer anatomic limitations as compared with right ventricular cannulation.

  11. Food analysis using artificial senses.

    PubMed

    Śliwińska, Magdalena; Wiśniewska, Paulina; Dymerski, Tomasz; Namieśnik, Jacek; Wardencki, Waldemar

    2014-02-19

    Nowadays, consumers are paying great attention to the characteristics of food such as smell, taste, and appearance. This motivates scientists to imitate human senses using devices known as electronic senses. These include electronic noses, electronic tongues, and computer vision. Thanks to the utilization of various sensors and methods of signal analysis, artificial senses are widely applied in food analysis for process monitoring and determining the quality and authenticity of foods. This paper summarizes achievements in the field of artificial senses. It includes a brief history of these systems, descriptions of most commonly used sensors (conductometric, potentiometric, amperometic/voltammetric, impedimetric, colorimetric, piezoelectric), data analysis methods (for example, artificial neural network (ANN), principal component analysis (PCA), model CIE L*a*b*), and application of artificial senses to food analysis, in particular quality control, authenticity and falsification assessment, and monitoring of production processes.

  12. Chemometric brains for artificial tongues.

    PubMed

    Oliveri, Paolo; Casolino, M Chiara; Forina, Michele

    2010-01-01

    The last years showed a significant trend toward the exploitation of rapid and economic analytical devices able to provide multiple information about samples. Among these, the so-called artificial tongues represent effective tools which allow a global sample characterization comparable to a fingerprint. Born as taste sensors for food evaluation, such devices proved to be useful for a wider number of purposes. In this review, a critical overview of artificial tongue applications over the last decade is outlined. In particular, the focus is centered on the chemometric techniques, which allow the extraction of valuable information from nonspecific data. The basic steps of signal processing and pattern recognition are discussed and the principal chemometric techniques are described in detail, highlighting benefits and drawbacks of each one. Furthermore, some novel methods recently introduced and particularly suitable for artificial tongue data are presented.

  13. Artificial Intelligence.

    PubMed

    Lawrence, David R; Palacios-González, César; Harris, John

    2016-04-01

    It seems natural to think that the same prudential and ethical reasons for mutual respect and tolerance that one has vis-à-vis other human persons would hold toward newly encountered paradigmatic but nonhuman biological persons. One also tends to think that they would have similar reasons for treating we humans as creatures that count morally in our own right. This line of thought transcends biological boundaries-namely, with regard to artificially (super)intelligent persons-but is this a safe assumption? The issue concerns ultimate moral significance: the significance possessed by human persons, persons from other planets, and hypothetical nonorganic persons in the form of artificial intelligence (AI). This article investigates why our possible relations to AI persons could be more complicated than they first might appear, given that they might possess a radically different nature to us, to the point that civilized or peaceful coexistence in a determinate geographical space could be impossible to achieve.

  14. Artificial Intelligence.

    PubMed

    Lawrence, David R; Palacios-González, César; Harris, John

    2016-04-01

    It seems natural to think that the same prudential and ethical reasons for mutual respect and tolerance that one has vis-à-vis other human persons would hold toward newly encountered paradigmatic but nonhuman biological persons. One also tends to think that they would have similar reasons for treating we humans as creatures that count morally in our own right. This line of thought transcends biological boundaries-namely, with regard to artificially (super)intelligent persons-but is this a safe assumption? The issue concerns ultimate moral significance: the significance possessed by human persons, persons from other planets, and hypothetical nonorganic persons in the form of artificial intelligence (AI). This article investigates why our possible relations to AI persons could be more complicated than they first might appear, given that they might possess a radically different nature to us, to the point that civilized or peaceful coexistence in a determinate geographical space could be impossible to achieve. PMID:26957450

  15. Artificial vision.

    PubMed

    Zarbin, M; Montemagno, C; Leary, J; Ritch, R

    2011-09-01

    A number treatment options are emerging for patients with retinal degenerative disease, including gene therapy, trophic factor therapy, visual cycle inhibitors (e.g., for patients with Stargardt disease and allied conditions), and cell transplantation. A radically different approach, which will augment but not replace these options, is termed neural prosthetics ("artificial vision"). Although rewiring of inner retinal circuits and inner retinal neuronal degeneration occur in association with photoreceptor degeneration in retinitis pigmentosa (RP), it is possible to create visually useful percepts by stimulating retinal ganglion cells electrically. This fact has lead to the development of techniques to induce photosensitivity in cells that are not light sensitive normally as well as to the development of the bionic retina. Advances in artificial vision continue at a robust pace. These advances are based on the use of molecular engineering and nanotechnology to render cells light-sensitive, to target ion channels to the appropriate cell type (e.g., bipolar cell) and/or cell region (e.g., dendritic tree vs. soma), and on sophisticated image processing algorithms that take advantage of our knowledge of signal processing in the retina. Combined with advances in gene therapy, pathway-based therapy, and cell-based therapy, "artificial vision" technologies create a powerful armamentarium with which ophthalmologists will be able to treat blindness in patients who have a variety of degenerative retinal diseases.

  16. A field investigation of a modified intravaginal progesterone releasing device and oestradiol benzoate based ovulation synchronisation protocol designed for fixed-time artificial insemination of Brahman heifers.

    PubMed

    Edwards, S A A; Boe-Hansen, G B; Satake, N; Chandra, K; McGowan, M R

    2015-09-01

    Pregnancy rates (PR) to fixed-time AI (FTAI) in Brahman heifers were compared after treatment with a traditional oestradiol-based protocol (OPO-8) or a modified protocol (OPO-6) where the duration of intravaginal progesterone releasing device (IPRD) was reduced from 8 to 6 days, and the interval from IPRD removal to oestradiol benzoate (ODB) was increased from 24 to 36 h. Rising 2 yo heifers on Farm A: (n = 238 and n = 215; two consecutive days AI); B (n = 271); and C (n = 393) were allocated to OPO-8 or OPO-6. An IPRD was inserted and 1mg ODB i.m. on Day 0 for OPO-8 heifers and Day 2 for OPO-6 heifers. On Day 8, the IPRD was removed and 500 μg cloprostenol i.m. At 24h, for OPO-8 heifers, and 36 h, for OPO-6 heifers, post IPRD removal all heifers received 1mg ODB i.m. FTAI was conducted at 54 and 72 h post IPRD removal for OPO-8 and OPO-6 heifers. At Farm A, OPO-6 heifers, AI on the second day, the PR was 52.4% to FTAI (P = 0.024) compared to 36.8% for OPO-8 heifers. However, no differences were found between OPO-8 and OPO-6 protocols at Farm A (first day of AI) (39.9 vs. 35.7%), or Farms B (26.2 vs. 35.4%) and C (43.2% vs. 40.3%). Presence of a corpus luteum at IPRD insertion affected PR to FTAI (43.9% vs. 28.8%; P < 0.001). This study has shown that the modified ovulation synchronisation protocol OPO-6 may be a viable alternative to the OPO-8 protocol for FTAI in B. indicus heifers. PMID:26282523

  17. Canadian Cardiovascular Society/Canadian Heart Rhythm Society joint position statement on the use of remote monitoring for cardiovascular implantable electronic device follow-up.

    PubMed

    Yee, Raymond; Verma, Atul; Beardsall, Marianne; Fraser, Jennifer; Philippon, Francois; Exner, Derek V

    2013-06-01

    Remote monitoring (RM) is a form of telemedicine technology that permits implanted pacemakers and implantable cardioverter-defibrillators to transmit diagnostic information for review by health care professionals without patients needing to visit the device follow-up clinic. A bedside transmitter in the patient's home conveys the device data using standard telecommunication protocol to a protected internet-accessible RM data server, which authorized health care professionals can access at any time using standard web browser software. Evidence indicates it can accelerate identification of clinical events and potential device problems. RM raises important medicolegal issues concerning the protection of a patient's rights and the safeguarding of patient health information related to the collection, storage, and use of patient device information that must be addressed by follow-up centres. This position statement recommends that remote monitoring be available at all device follow-up clinics as an integral part of the standard of care of device patients and also provides helpful advice to centres for the proper design, implementation, and integration of a remote monitoring system into the clinic.

  18. Keeping Hearts Pumping

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A collaboration between NASA, Dr. Michael DeBakey, Dr. George Noon, and MicroMed Technology, Inc., resulted in a life-saving heart pump for patients awaiting heart transplants. The MicroMed DeBakey VAD functions as a "bridge to heart transplant" by pumping blood throughout the body to keep critically ill patients alive until a donor heart is available. Weighing less than 4 ounces and measuring 1 inch by 3 inches, the pump is approximately one-tenth the size of other currently marketed pulsatile VADs. This makes it less invasive and ideal for smaller adults and children. Because of the pump's small size, less than 5 percent of the patients implanted developed device-related infections. It can operate up to 8 hours on batteries, giving patients the mobility to do normal, everyday activities.The MicroMed DeBakey VAD is a registered trademark of MicroMed Technology, Inc.

  19. Tissue engineering and cell-based therapy toward integrated strategy with artificial organs.

    PubMed

    Gojo, Satoshi; Toyoda, Masashi; Umezawa, Akihiro

    2011-09-01

    Research in order that artificial organs can supplement or completely replace the functions of impaired or damaged tissues and internal organs has been underway for many years. The recent clinical development of implantable left ventricular assist devices has revolutionized the treatment of patients with heart failure. The emerging field of regenerative medicine, which uses human cells and tissues to regenerate internal organs, is now advancing from basic and clinical research to clinical application. In this review, we focus on the novel biomaterials, i.e., fusion protein, and approaches such as three-dimensional and whole-organ tissue engineering. We also compare induced pluripotent stem cells, directly reprogrammed cardiomyocytes, and somatic stem cells for cell source of future cell-based therapy. Integrated strategy of artificial organ and tissue engineering/regenerative medicine should give rise to a new era of medical treatment to organ failure.

  20. Heart palpitations

    MedlinePlus

    ... more than 6 per minute or coming in groups of 3 or more). You have risk factors for heart disease, such as high cholesterol, diabetes, or high blood pressure. You have new or different heart palpitations. ...

  1. Heart Disease

    MedlinePlus

    ... with heart disease? What do my cholesterol and triglyceride numbers mean? How can I lower my cholesterol? ... weight Know your numbers (blood pressure, cholesterol, and triglycerides) You can reduce your chances of getting heart ...

  2. Heart transplant

    MedlinePlus

    ... PA: Elsevier Saunders; 2014:chap 28. Bernstein D. Pediatric heart and heart-lung transplantation. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics . 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap ...

  3. Heart pacemaker

    MedlinePlus

    ... 1 ounce. Most pacemakers have 2 parts: The generator contains the battery and the information to control ... are wires that connect the heart to the generator and carry the electrical messages to the heart. ...

  4. Artificial vision workbench.

    PubMed

    Frenger, P

    1997-01-01

    Machine vision is an important component of medical systems engineering. Inexpensive miniature solid state cameras are now available. This paper describes how these devices can be used as artificial retinas, to take snapshots and moving pictures in monochrome or color. Used in pairs, they produce a stereoscopic field of vision and enable depth perception. Macular and peripheral vision can be simulated electronically. This paper also presents the author's design of an artificial orbit for this synthetic eye. The orbit supports the eye, protects it, and provides attachment points for the ocular motion control system. Convergence and image fusion can be produced, and saccades simulated, along with the other ocular motions. The use of lenses, filters, irises and focusing mechanisms are also discussed. Typical camera-computer interfaces are described, including the use of "frame grabbers" and analog-to-digital image conversion. Software programs for eye positioning, image manipulation, feature extraction and object recognition are discussed, including the application of artificial neural networks. PMID:9731383

  5. [Liver and artificial liver].

    PubMed

    Chamuleau, R A

    1998-06-01

    Despite good results of orthotopic liver transplantation in patients with fulminant hepatic failure the need still exists for an effective and safe artificial liver, able to temporarily take over the complex liver function so as to bridge the gap with transplantation or regeneration. Attempts to develop non-biological artificial livers have failed, mostly when controlled clinical trials were performed. In the last decade several different types of bioartificial livers have been devised, in which the biocomponent consists of freshly isolated porcine hepatocytes or a human hepatoblastoma cell line. The majority use semipermeable hollow fibers known from artificial kidney devices. The liver cells may lie either inside or outside the lumen of these fibers. In vitro analysis of liver function and animal experimental work showing that the bioartificial liver increases survival justify clinical application. Bioartificial livers are connected to patients extracorporeally by means of plasmapheresis circuit for periods of about 6 hours. In different trials about 40 patients with severe liver failure have been treated. No important adverse effects have not been reported in these phase I trials. Results of controlled studies are urgently needed. As long as no satisfactory immortalised human liver cell line with good function is available, porcine hepatocytes will remain the first choice, provided transmission of porcine pathogens to man is prevented. PMID:9752034

  6. Artificial Intelligence

    SciTech Connect

    Shirai, Y.; Tsujii, Jun-ichi

    1985-01-01

    Based on the Japanese 5th Generation Computer Program, this volume provides coverage of the fundamental concepts and various techniques in the different applications of Artificial Intelligence. Also presented are the methods which can be used to put these concepts and techniques into practice. Explanations are presented of all the basic topics in the field, including the representation of problems; searching techniques; the control of problem solving; programming languages for Al, such as LISP, PLANNER, CONNIVER, and PROLOG; the representation and utilization of knowledge; and the approach to human intelligence.

  7. Heart Attack

    MedlinePlus

    ... a million people in the U.S. have a heart attack. About half of them die. Many people have permanent heart damage or die because they don't get ... It's important to know the symptoms of a heart attack and call 9-1-1 if someone ...

  8. Implantable Heart Aid

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Medrad utilized NASA's Apollo technology to develop a new device called the AID implantable automatic pulse generator which monitors the heart continuously, recognizes the onset of ventricular fibrillation and delivers a corrective electrical shock. AID pulse generator is, in effect, a miniaturized version of the defibrillator used by emergency squads and hospitals to restore rhythmic heartbeat after fibrillation, but has the unique advantage of being permanently available to the patient at risk. Once implanted, it needs no specially trained personnel or additional equipment. AID system consists of a microcomputer, a power source and two electrodes which sense heart activity.

  9. Artificial gravity.

    PubMed

    Scott, William B

    2005-04-25

    NASA's Artificial Gravity program consists of a team of researchers from Wyle Laboratories, NASA Johnson Space Center, and the University of Texas Medical Branch (UTMB). The short-radius centrifuge (SRC), built by Wyle Laboratories, will be integrated with UTMB's conducted bedrest studies, which mimic the detrimental effects of weightlessness (or microgravity). Bedrest subjects will be spun on the SRC at various accelerations and for various time periods, while being monitored medically. Parameters such as bone loss, muscle atrophy, balance control, and oxygen consumption will then be compared in order to research ways of mitigating the impact on astronauts' physiology. Other potential benefits from these studies extend to population groups on Earth, such as bedridden patients. PMID:15852559

  10. Artificial rheotaxis

    PubMed Central

    Palacci, Jérémie; Sacanna, Stefano; Abramian, Anaïs; Barral, Jérémie; Hanson, Kasey; Grosberg, Alexander Y.; Pine, David J.; Chaikin, Paul M.

    2015-01-01

    Motility is a basic feature of living microorganisms, and how it works is often determined by environmental cues. Recent efforts have focused on developing artificial systems that can mimic microorganisms, in particular their self-propulsion. We report on the design and characterization of synthetic self-propelled particles that migrate upstream, known as positive rheotaxis. This phenomenon results from a purely physical mechanism involving the interplay between the polarity of the particles and their alignment by a viscous torque. We show quantitative agreement between experimental data and a simple model of an overdamped Brownian pendulum. The model notably predicts the existence of a stagnation point in a diverging flow. We take advantage of this property to demonstrate that our active particles can sense and predictably organize in an imposed flow. Our colloidal system represents an important step toward the realization of biomimetic microsystems with the ability to sense and respond to environmental changes. PMID:26601175

  11. A micro-spherical heart pump powered by cultured cardiomyocytes.

    PubMed

    Tanaka, Yo; Sato, Kae; Shimizu, Tatsuya; Yamato, Masayuki; Okano, Teruo; Kitamori, Takehiko

    2007-02-01

    Miniaturization of chemical or biochemical systems creates extremely efficient devices exploiting the advantages of microspaces. Although they are often targeted for implanted tissue engineered organs or drug-delivery devices because of their highly integrated systems, microfluidic devices are usually powered by external energy sources and therefore difficult to be used in vivo. A microfluidic device powered without the need for external energy sources or stimuli is needed. Previously, we demonstrated the concept of a cardiomyocyte pump using only chemical energy input to cells as a driver (Yo Tanaka, Keisuke Morishima, Tatsuya Shimizu, Akihiko Kikuchi, Masayuki Yamato, Teruo Okano and Takehiko Kitamori, Lab Chip, 6(3), pp. 362-368). However, the structure of this prototype pump described there included complicated mechanical components and fabricated compartments. Here, we have created a micro-spherical heart-like pump powered by spontaneously contracting cardiomyocyte sheets driven without a need for external energy sources or coupled stimuli. This device was fabricated by wrapping a beating cardiomyocyte sheet exhibiting large contractile forces around a fabricated hollow elastomeric sphere (5 mm diameter, 250 microm polymer thickness) fixed with inlet and outlet ports. Fluid oscillations in a capillary connected to the hollow sphere induced by the synchronously pulsating cardiomyocyte sheet were confirmed, and the device continually worked for at least 5 days in this system. This bio/artificial hybrid fluidic pump device is innovative not only because it is driven by cells using only chemical energy input, but also because the design is an optimum structure (sphere). We anticipate that this device might be applied for various purposes including a bio-actuator for medical implant devices that relies on biochemical energy, not electrical interfacing. PMID:17268623

  12. A micro-spherical heart pump powered by cultured cardiomyocytes.

    PubMed

    Tanaka, Yo; Sato, Kae; Shimizu, Tatsuya; Yamato, Masayuki; Okano, Teruo; Kitamori, Takehiko

    2007-02-01

    Miniaturization of chemical or biochemical systems creates extremely efficient devices exploiting the advantages of microspaces. Although they are often targeted for implanted tissue engineered organs or drug-delivery devices because of their highly integrated systems, microfluidic devices are usually powered by external energy sources and therefore difficult to be used in vivo. A microfluidic device powered without the need for external energy sources or stimuli is needed. Previously, we demonstrated the concept of a cardiomyocyte pump using only chemical energy input to cells as a driver (Yo Tanaka, Keisuke Morishima, Tatsuya Shimizu, Akihiko Kikuchi, Masayuki Yamato, Teruo Okano and Takehiko Kitamori, Lab Chip, 6(3), pp. 362-368). However, the structure of this prototype pump described there included complicated mechanical components and fabricated compartments. Here, we have created a micro-spherical heart-like pump powered by spontaneously contracting cardiomyocyte sheets driven without a need for external energy sources or coupled stimuli. This device was fabricated by wrapping a beating cardiomyocyte sheet exhibiting large contractile forces around a fabricated hollow elastomeric sphere (5 mm diameter, 250 microm polymer thickness) fixed with inlet and outlet ports. Fluid oscillations in a capillary connected to the hollow sphere induced by the synchronously pulsating cardiomyocyte sheet were confirmed, and the device continually worked for at least 5 days in this system. This bio/artificial hybrid fluidic pump device is innovative not only because it is driven by cells using only chemical energy input, but also because the design is an optimum structure (sphere). We anticipate that this device might be applied for various purposes including a bio-actuator for medical implant devices that relies on biochemical energy, not electrical interfacing.

  13. Internet advertising of artificial tanning in Australia.

    PubMed

    Team, Victoria; Markovic, Milica

    2006-08-01

    Artificial tanning, defined as deliberate exposure to ultraviolet rays produced by artificial tanning devices, is a new and emerging public health issue in Australia and globally. Epidemiological research suggests that artificial tanning may contribute to the incidence of melanoma, nonmelanoma skin cancer as well as other health problems. Given that Australia has a high incidence of skin cancer, we have undertaken a study to explore how artificial tanning has been promoted to its users. The aim was to analyze the completeness and accuracy of information about artificial tanning. A content analysis of web sites of tanning salons and distributors of tanning equipment in Australia was conducted. A total of 22 web sites were analyzed. None of the solarium operators or distributors of equipment provided full information about the risks of artificial tanning. Fifty-nine percent of web advertisements had no information and 41% provided only partial information regarding the risks of artificial tanning. Pictures with the image of bronze-tanned bodies, predominantly women, were used by all web advertisers. In light of the success of sun-safety campaigns in Australia, the findings of future epidemiological research on the prevalence of artificial tanning and sociological and anthropological research on why people utilize artificial tanning should be a basis for developing effective targeted health promotion on the elimination of artificial tanning in the country.

  14. Efficacy and learning curve of a hand-held echocardiography device in an oncology outpatient clinic: Expanding the use of echoscopic heart examination beyond cardiology

    PubMed Central

    PéREZ DE ISLA, LEOPOLDO PÉREZ; MORENO, FERNANDO; GARCIA SAEZ, JOSE ANGEL GARCIA; CLAVERO, MATIAS; MORENO, NUNO; AGUADO DE LA ROSA, CARLOS AGUADO; DE AGUSTIN, JOSE ALBERTO; GOMEZ DE DIEGO, JOSE JUAN GOMEZ; COBOS, MIGUEL ANGEL; SALTIJERAL, ADRIANA; MACAYA, CARLOS; GARCIA-FERNANDEZ, MIGUEL ANGEL

    2015-01-01

    Certain chemotherapy drugs for breast cancer may induce cardiotoxicity and these patients should be echocardiographically monitored. The performance of a focused echocardiographic evaluation (echoscopy) at the patient's location by a non-cardiologist appears to be feasible. The aim of the present study was to assess the accuracy of echoscopy performed by medical oncologists in an outpatient clinic using hand-held echocardiography devices. The study cohort comprised consecutive unselected patients who attended an oncology outpatient clinic. Two medical oncologists attended a one-week training period, which included theoretical and practical teaching by an expert cardiologist. Every subject underwent two echo examinations. The first examination was performed by an oncologist using a hand-held echo device and the second was performed by a cardiologist using a ‘premium’ device. Out of the 101 enrolled patients, 32 were men (31.7%) and the mean age was 56.03±16.88 years. There was a good global agreement [intra-class correlation coefficient (ICC): 0.65 for left ventricular ejection fraction (LVEF)]. When the results were analyzed depending on the period of time when the echo studies were performed, a clear and short learning curve was observed: LVEF started at ICC=0.58 and increased to 0.66 and 0.77 in the second and third period, respectively. There were extremely few clinically significant differences and a learning curve was also evident. In conclusion, cardiac echoscopy performed by an oncologist with a hand-held device may lead to a similar clinical management as a study performed by an expert cardiologist with a ‘premium’ system in patients under chemotherapy following a short training period. PMID:26171188

  15. 21 CFR 870.3925 - Replacement heart valve.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Replacement heart valve. 870.3925 Section 870.3925... valve. (a) Identification. A replacement heart valve is a device intended to perform the function of any of the heart's natural valves. This device includes valves constructed of prosthetic...

  16. 21 CFR 870.3925 - Replacement heart valve.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Replacement heart valve. 870.3925 Section 870.3925... valve. (a) Identification. A replacement heart valve is a device intended to perform the function of any of the heart's natural valves. This device includes valves constructed of prosthetic...

  17. Heart regeneration.

    PubMed

    Breckwoldt, Kaja; Weinberger, Florian; Eschenhagen, Thomas

    2016-07-01

    Regenerating an injured heart holds great promise for millions of patients suffering from heart diseases. Since the human heart has very limited regenerative capacity, this is a challenging task. Numerous strategies aiming to improve heart function have been developed. In this review we focus on approaches intending to replace damaged heart muscle by new cardiomyocytes. Different strategies for the production of cardiomyocytes from human embryonic stem cells or human induced pluripotent stem cells, by direct reprogramming and induction of cardiomyocyte proliferation are discussed regarding their therapeutic potential and respective advantages and disadvantages. Furthermore, different methods for the transplantation of pluripotent stem cell-derived cardiomyocytes are described and their clinical perspectives are discussed. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.

  18. Hypoplastic left heart syndrome

    MedlinePlus

    HLHS; Congenital heart - hypoplastic left heart; Cyanotic heart disease - hypoplastic left heart ... Hypoplastic left heart is a rare type of congenital heart disease. It is more common in males than in females. As ...

  19. Usefulness of cardiac resynchronisation therapy devices and implantable cardioverter defibrillators in the treatment of heart failure due to severe systolic dysfunction: systematic review of clinical trials and network meta-analysis

    PubMed Central

    García García, M A; Rosero Arenas, M A; Ruiz Granell, R; Chorro Gascó, F J; Martínez Cornejo, A

    2016-01-01

    Aim To assess the effectiveness of cardiac resynchronisation therapy (CRT), implantable cardioverter defibrillator (ICD) therapy, and the combination of these devices (CRT+ICD) in adult patients with left ventricular dysfunction and symptomatic heart failure. Methods A comprehensive systematic review of randomised clinical trials was conducted. Several electronic databases (PubMed, Embase, Ovid, Cochrane, ClinicalTrials.gov) were reviewed. The mortality rates between treatments were compared. A network was established comparing the various options, and direct, indirect and mixed comparisons were made using multivariate meta-regression. The degree of clinical and statistical homogeneity was assessed. Results 43 trials involving 13 017 patients were reviewed. Resynchronisation therapy, defibrillators, and combined devices (CRT+ICD) are clearly beneficial compared to optimal medical treatment, showing clear benefit in all of these cases. In a theoretical order of efficiency, the first option is combined therapy (CRT+ICD), the second is CRT, and the third is defibrillator implantation (ICD). Given the observational nature of these comparisons, and the importance of the overlapping CIs, we cannot state that the combined option (CRT+ICD) offers superior survival benefit compared to the other two options. Conclusions The combined option of CRT+ICD seems to be better than the option of CRT alone, although no clear improvement in survival was found for the combined option. It would be advisable to perform a direct comparative study of these two options. PMID:27326223

  20. Heart failure.

    PubMed

    2014-12-15

    Essential facts Heart failure affects about 900,000 people in the UK. The condition can affect people of all ages, but it is more common in older people, with more than half of all patients over the age of 75. It is caused by the heart failing to pump enough blood around the body at the right pressure, usually because the heart muscle has become too weak or stiff to work properly. Acute heart failure, which occurs when symptoms develop quickly, is the leading cause of hospital admission in people over 65. PMID:25492766

  1. Ventricular assist devices: The future is now.

    PubMed

    Lima, Brian; Mack, Michael; Gonzalez-Stawinski, Gonzalo V

    2015-05-01

    Heart failure has become a global epidemic. For advanced heart failure, a broad assortment of device options have been introduced for both acute and prolonged intervals of hemodynamic assistance. Durable implantable ventricular assist devices (VADs) in particular play a key role in the management of advanced heart failure. This review focuses specifically on the current outcomes with VAD therapy, highlights the results from pivotal clinical trials, and summarizes the various device options on the market and those in preclinical development. PMID:25596799

  2. Heart Imaging System

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Johnson Space Flight Center's device to test astronauts' heart function in microgravity has led to the MultiWire Gamma Camera, which images heart conditions six times faster than conventional devices. Dr. Jeffrey Lacy, who developed the technology as a NASA researcher, later formed Proportional Technologies, Inc. to develop a commercially viable process that would enable use of Tantalum-178 (Ta-178), a radio-pharmaceutical. His company supplies the generator for the radioactive Ta-178 to Xenos Medical Systems, which markets the camera. Ta-178 can only be optimally imaged with the camera. Because the body is subjected to it for only nine minutes, the radiation dose is significantly reduced and the technique can be used more frequently. Ta-178 also enables the camera to be used on pediatric patients who are rarely studied with conventional isotopes because of the high radiation dosage.

  3. Cybersecurity in Artificial Pancreas Experiments.

    PubMed

    O'Keeffe, Derek T; Maraka, Spyridoula; Basu, Ananda; Keith-Hynes, Patrick; Kudva, Yogish C

    2015-09-01

    Medical devices have transformed modern health care, and ongoing experimental medical technology trials (such as the artificial pancreas) have the potential to significantly improve the treatment of several chronic conditions, including diabetes mellitus. However, we suggest that, to date, the essential concept of cybersecurity has not been adequately addressed in this field. This article discusses several key issues of cybersecurity in medical devices and proposes some solutions. In addition, it outlines the current requirements and efforts of regulatory agencies to increase awareness of this topic and to improve cybersecurity. PMID:25923544

  4. Cybersecurity in Artificial Pancreas Experiments

    PubMed Central

    O'Keeffe, Derek T.; Maraka, Spyridoula; Basu, Ananda; Keith-Hynes, Patrick

    2015-01-01

    Abstract Medical devices have transformed modern health care, and ongoing experimental medical technology trials (such as the artificial pancreas) have the potential to significantly improve the treatment of several chronic conditions, including diabetes mellitus. However, we suggest that, to date, the essential concept of cybersecurity has not been adequately addressed in this field. This article discusses several key issues of cybersecurity in medical devices and proposes some solutions. In addition, it outlines the current requirements and efforts of regulatory agencies to increase awareness of this topic and to improve cybersecurity. PMID:25923544

  5. A programmable artificial retina

    SciTech Connect

    Bernard, T.M. ); Zavidovique, B.Y. . Electrical Engineering Dept. Perception System Lab., Arcueil ); Devos, F.J. . Dept. of Integrated Circuits and Systems)

    1993-07-01

    An artificial retina is a device that intimately associates an imager with processing facilities on a monolithic circuit. Yet, except for simple environments and applications, analog hardware will not suffice to process and compact the raw image flow from the photosensitive array. To solve this output problem, an on-chip array of bare Boolean processors with halftoning facilities might be used, providing versatility from programmability. By setting the pixel memory size to 3 b, the authors have demonstrated both the technological practicality and the computational efficiency of this programmable Boolean retina concept. Using semi-static shifting structures together with some interaction circuitry, a minimal retina Boolean processor can be built with less than 30 transistors and controlled by as few as 6 global clock signals. The successful design, integration, and test of such a 65x76 Boolean retina on a 50-mm[sup 2] CMOS 2-[mu]m circuit are presented.

  6. Heart Failure

    MedlinePlus

    ... of breath Common causes of heart failure are coronary artery disease, high blood pressure and diabetes. It is more common in people who are 65 years old or older, African Americans, people who are ... treatments fail. NIH: National Heart, Lung, and Blood Institute

  7. Intervention for advanced heart failure patients and their caregivers to support shared decision-making about implantation of a ventricular assist device.

    PubMed

    Gauthier, Marie-Andrée; Cossette, Sylvie; Ouimette, Marie-France; Harris, Virginie

    2016-01-01

    This project aimed to co-develop and pilot an intervention plan to support shared decision-making (SDM) for patients considering a ventricular assist device (VAD), their caregivers and the health care team. The project involved a focus group with patients and caregivers to explore their decision-making needs along with regular participation in team meetings resulting in the creation of a decision aid. The decision aid answered needs expressed by patients and caregivers, as well as the team's initial needsfor informational support, optimization of information exchange and process standardization. A workshop on SDM was also conducted to increase competence toward this approach and the use of the decision aid. This project is timely and relevant given the increase in VAD implantation in Canada. The intervention could also be applicable to other decision-making situations in which active participation can improve the quality of the decision process. PMID:27382666

  8. Artificial neural interfaces for bionic cardiovascular treatments.

    PubMed

    Kawada, Toru; Sugimachi, Masaru

    2009-01-01

    An artificial nerve, in the broad sense, may be conceptualized as a physical and logical interface system that reestablishes the information traffic between the central nervous system and peripheral organs. Studies on artificial nerves targeting the autonomic nervous system are in progress to explore new treatment strategies for several cardiovascular diseases. In this article, we will review our research targeting the autonomic nervous system to treat cardiovascular diseases. First, we identified the rule for decoding native sympathetic nerve activity into a heart rate using transfer function analysis, and established a framework for a neurally regulated cardiac pacemaker. Second, we designed a bionic baroreflex system to restore the baroreflex buffering function using electrical stimulation of the celiac ganglion in a rat model of orthostatic hypotension. Third, based on the hypothesis that autonomic imbalance aggravates chronic heart failure, we implanted a neural interface into the right vagal nerve and demonstrated that intermittent vagal stimulation significantly improved the survival rate in rats with chronic heart failure following myocardial infarction. Although several practical problems need to be resolved, such as those relating to the development of electrodes feasible for long-term nerve activity recording, studies of artificial neural interfaces with the autonomic nervous system have great possibilities in the field of cardiovascular treatment. We expect further development of artificial neural interfaces as novel strategies to cope with cardiovascular diseases resistant to conventional therapeutics.

  9. 21 CFR 870.2860 - Heart sound transducer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Heart sound transducer. 870.2860 Section 870.2860 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2860 Heart sound...

  10. Simple, heart-smart substitutions

    MedlinePlus

    Coronary artery disease - heart smart substitutions; Atherosclerosis - heart smart substitutions; Cholesterol - heart smart substitutions; Coronary heart disease - heart smart substitutions; Healthy diet - heart ...

  11. Application of the moving-actuator type pump as a ventricular assist device: in vitro and in vivo studies.

    PubMed

    Lee, H S; Rho, Y R; Park, C Y; Hwang, C M; Kim, W G; Sun, K; Choi, M J; Lee, K K; Cheong, J T; Shim, E B; Min, B G

    2002-06-01

    A moving actuator type pump has been developed as a multifunctional Korean artificial heart (AnyHeart). The pump consists of a moving actuator as an energy converter, right and left sacs, polymer (or mechanical) valves, and a rigid polyurethane housing. The actuator containing a brushless DC motor moves back and forth on an epicyclical gear train to produce a pendular motion, which compresses both sacs alternately. Of its versatile functions of ventricular assist device and total artificial heart use, we have evaluated the system performance as a single or biventricular assist device through in vitro and in vivo experiments. Pump performance and anatomical feasibility were tested using various animals of different sizes. In the case of single ventricular assist device (VAD) use, one of the sacs remained empty and a mini-compliance chamber was attached to either an outflow or inflow port of the unused sac. The in vitro and in vivo studies show acceptable performance and pump behavior. Further extensive study is required to proceed to human application.

  12. Biomaterials and Biomedical Devices

    NASA Astrophysics Data System (ADS)

    Hanker, Jacob S.; Giammara, Beverly L.

    1988-11-01

    This review discusses the factors important in the incorporation or integration of biomaterials and devices by tissue. Methods for surface modification and surface-sensitive techniques for analysis are cited. In vitro methods to evaluate the biocompatibility or efficacy of certain biomaterials and devices are presented. Present and future directions in neural prostheses, cardiovascular materials, blood or bone substitutes, controlled drug delivery, orthopedic prostheses, dental materials, artificial organs, plasma- and cytapheresis, and dialysis are discussed.

  13. Heart Attack

    MedlinePlus

    ... lower “bad” cholesterol (also called LDL, or low-density lipoprotein) levels and may help increase “good” cholesterol (also called HDL, or high-density lipoprotein). If you have had a heart attack, ...

  14. Hearts Wish.

    ERIC Educational Resources Information Center

    Jones, Lethonee A.

    1989-01-01

    Investigates characteristics and themes in 102 drawings by sexually abused children. Themes of the drawings included genitalia, the absence of specific body parts, phallic symbols, inappropriate smiles, distorted body images, kinetic activity, prominent hands and fingers, and hearts. (RJC)

  15. Heart Transplant

    MedlinePlus

    ... Doctors remove the patient's heart by transecting the aorta , the main pulmonary artery and the superior and ... sewing together the recipient and donor vena cavae, aorta, pulmonary artery and left atrium. In patients with ...

  16. Wine and heart health

    MedlinePlus

    Health and wine; Wine and heart disease; Preventing heart disease - wine; Preventing heart disease - alcohol ... often just to lower your risk of heart disease. Heavier drinking can harm the heart and liver. ...

  17. What Is Heart Failure?

    MedlinePlus

    ... page from the NHLBI on Twitter. What Is Heart Failure? Heart failure is a condition in which the heart can' ... force. Some people have both problems. The term "heart failure" doesn't mean that your heart has stopped ...

  18. Approval of high-risk medical devices in the US: implications for clinical cardiology.

    PubMed

    Rome, Benjamin N; Kramer, Daniel B; Kesselheim, Aaron S

    2014-01-01

    Since 1976, the US Food and Drug Administration (FDA) has used the premarket approval (PMA) process to approve high-risk medical devices, including implantable cardioverter defibrillators (ICDs), coronary stents, and artificial heart valves. The PMA process is widely viewed as a rigorous evaluation of device safety and effectiveness, though recent recalls-most notably related to underperforming ICD leads-have raised concerns about whether physicians and patients should sometimes be more wary about devices approved via this pathway. The FDA must utilize a "least burdensome" approach to approve new medical devices, and many widely used device models have been approved as supplements to existing PMA-approved devices with limited clinical testing. A recent Supreme Court ruling has made it difficult for patients harmed by unsafe PMA-approved devices to seek damages in court. Cardiologists who utilize high-risk medical devices should be aware that FDA approval of new devices relies on variable levels of evidence and does not necessarily indicate improved effectiveness over existing models. Clinician and patient engagement in postmarket surveillance and comparative effectiveness research remains imperative. PMID:24760423

  19. Approval of high-risk medical devices in the US: implications for clinical cardiology.

    PubMed

    Rome, Benjamin N; Kramer, Daniel B; Kesselheim, Aaron S

    2014-01-01

    Since 1976, the US Food and Drug Administration (FDA) has used the premarket approval (PMA) process to approve high-risk medical devices, including implantable cardioverter defibrillators (ICDs), coronary stents, and artificial heart valves. The PMA process is widely viewed as a rigorous evaluation of device safety and effectiveness, though recent recalls-most notably related to underperforming ICD leads-have raised concerns about whether physicians and patients should sometimes be more wary about devices approved via this pathway. The FDA must utilize a "least burdensome" approach to approve new medical devices, and many widely used device models have been approved as supplements to existing PMA-approved devices with limited clinical testing. A recent Supreme Court ruling has made it difficult for patients harmed by unsafe PMA-approved devices to seek damages in court. Cardiologists who utilize high-risk medical devices should be aware that FDA approval of new devices relies on variable levels of evidence and does not necessarily indicate improved effectiveness over existing models. Clinician and patient engagement in postmarket surveillance and comparative effectiveness research remains imperative.

  20. Cardiac changes due to electronic control devices? A computer-based analysis of electrical effects at the human heart caused by an ECD pulse applied to the body's exterior.

    PubMed

    Kunz, Sebastian N; Aronshtam, Julia; Tränkler, Hans-Rolf; Kraus, Sybille; Graw, Matthias; Peschel, Oliver

    2014-05-01

    Electronic control devices (ECDs) deliver high-voltage, low-current energy pulses temporarily paralyzing a person. For the ECD-human interaction, we have developed a computer model using the SEMCAD program within which to simulate the electrical effects throughout the body resulting from the imposition of an ECD pulse at a particular point on the body surface. Our human body models were based on cross-sectional MRIs and CT scans, with the dielectric properties of the various tissues assigned based on previously published values. We simulated the application of a single ECD pulse and calculated the resulting electric field strength and current and charge densities at different body locations. The results were compared with corresponding values obtained by other researchers in similar simulations. Furthermore, we simulated an application of a pulse of 20-millisecond duration equal to the European household current of 50 Hz and to the ventricular fibrillation threshold. The resulting current level indicated at the heart muscle was 1/5 the level considered the threshold for triggering ventricular fibrillation. PMID:24712742

  1. 21 CFR 874.3375 - Battery-powered artificial larynx.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Battery-powered artificial larynx. 874.3375 Section 874.3375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3375...

  2. 21 CFR 874.3375 - Battery-powered artificial larynx.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Battery-powered artificial larynx. 874.3375 Section 874.3375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3375...

  3. 21 CFR 874.3375 - Battery-powered artificial larynx.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Battery-powered artificial larynx. 874.3375 Section 874.3375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3375...

  4. Trends in Artificial Intelligence.

    ERIC Educational Resources Information Center

    Hayes, Patrick

    1978-01-01

    Discusses the foundations of artificial intelligence as a science and the types of answers that may be given to the question, "What is intelligence?" The paradigms of artificial intelligence and general systems theory are compared. (Author/VT)

  5. The promise of microfluidic artificial lungs.

    PubMed

    Potkay, Joseph A

    2014-11-01

    Microfluidic or microchannel artificial lungs promise to enable a new class of truly portable, therapeutic artificial lungs through feature sizes and blood channel designs that closely mimic those found in their natural counterpart. These new artificial lungs could potentially: 1) have surface areas and priming volumes that are a fraction of current technologies thereby decreasing device size and reducing the foreign body response; 2) contain blood flow networks in which cells and platelets experience pressures, shear stresses, and branching angles that copy those in the human lung thereby improving biocompatibility; 3) operate efficiently with room air, eliminating the need for gas cylinders and complications associated with hyperoxemia; 4) exhibit biomimetic hydraulic resistances, enabling operation with natural pressures and eliminating the need for blood pumps; and, 5) provide increased gas exchange capacity enabling respiratory support for active patients. This manuscript reviews recent research efforts in microfluidic artificial lungs targeted at achieving the advantages above, investigates the ultimate performance and scaling limits of these devices using a proven mathematical model, and discusses the future challenges that must be overcome in order for microfluidic artificial lungs to be applied in the clinic. If all of these promising advantages are realized and the remaining challenges are met, microfluidic artificial lungs could revolutionize the field of pulmonary rehabilitation.

  6. Artificial life and Piaget.

    PubMed

    Mueller, Ulrich; Grobman, K H.

    2003-04-01

    Artificial life provides important theoretical and methodological tools for the investigation of Piaget's developmental theory. This new method uses artificial neural networks to simulate living phenomena in a computer. A recent study by Parisi and Schlesinger suggests that artificial life might reinvigorate the Piagetian framework. We contrast artificial life with traditional cognitivist approaches, discuss the role of innateness in development, and examine the relation between physiological and psychological explanations of intelligent behaviour.

  7. Methods of failure and reliability assessment for mechanical heart pumps.

    PubMed

    Patel, Sonna M; Allaire, Paul E; Wood, Houston G; Throckmorton, Amy L; Tribble, Curt G; Olsen, Don B

    2005-01-01

    Artificial blood pumps are today's most promising bridge-to-recovery (BTR), bridge-to-transplant (BTT), and destination therapy solutions for patients suffering from intractable congestive heart failure (CHF). Due to an increased need for effective, reliable, and safe long-term artificial blood pumps, each new design must undergo failure and reliability testing, an important step prior to approval from the United States Food and Drug Administration (FDA), for clinical testing and commercial use. The FDA has established no specific standards or protocols for these testing procedures and there are only limited recommendations provided by the scientific community when testing an overall blood pump system and individual system components. Product development of any medical device must follow a systematic and logical approach. As the most critical aspects of the design phase, failure and reliability assessments aid in the successful evaluation and preparation of medical devices prior to clinical application. The extent of testing, associated costs, and lengthy time durations to execute these experiments justify the need for an early evaluation of failure and reliability. During the design stages of blood pump development, a failure modes and effects analysis (FMEA) should be completed to provide a concise evaluation of the occurrence and frequency of failures and their effects on the overall support system. Following this analysis, testing of any pump typically involves four sequential processes: performance and reliability testing in simple hydraulic or mock circulatory loops, acute and chronic animal experiments, human error analysis, and ultimately, clinical testing. This article presents recommendations for failure and reliability testing based on the National Institutes of Health (NIH), Society for Thoracic Surgeons (STS) and American Society for Artificial Internal Organs (ASAIO), American National Standards Institute (ANSI), the Association for Advancement of

  8. Mechanically activated artificial cell by using microfluidics

    PubMed Central

    Ho, Kenneth K. Y.; Lee, Lap Man; Liu, Allen P.

    2016-01-01

    All living organisms sense mechanical forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a deformable flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our mechanically activated artificial cell through thinning of oil. The development of a microfluidic device to mechanically activate artificial cells creates new opportunities in force-activated synthetic biology. PMID:27610921

  9. Mechanically activated artificial cell by using microfluidics.

    PubMed

    Ho, Kenneth K Y; Lee, Lap Man; Liu, Allen P

    2016-01-01

    All living organisms sense mechanical forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a deformable flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our mechanically activated artificial cell through thinning of oil. The development of a microfluidic device to mechanically activate artificial cells creates new opportunities in force-activated synthetic biology. PMID:27610921

  10. Mechanically activated artificial cell by using microfluidics.

    PubMed

    Ho, Kenneth K Y; Lee, Lap Man; Liu, Allen P

    2016-01-01

    All living organisms sense mechanical forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a deformable flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our mechanically activated artificial cell through thinning of oil. The development of a microfluidic device to mechanically activate artificial cells creates new opportunities in force-activated synthetic biology.

  11. Framingham Heart Study

    ClinicalTrials.gov

    2016-04-13

    Cardiovascular Diseases; Heart Diseases; Coronary Disease; Cerebrovascular Accident; Hypertension; Heart Failure, Congestive; Peripheral Vascular Diseases; Arterial Occlusive Diseases; Atherosclerosis; Heart Failure

  12. Cardiovascular devices; reclassification of intra-aortic balloon and control systems for acute coronary syndrome, cardiac and non-cardiac surgery, or complications of heart failure; effective date of requirement for premarket approval for intra-aortic balloon and control systems for septic shock or pulsatile flow generation. Final order.

    PubMed

    2013-12-30

    The Food and Drug Administration (FDA) is issuing a final order to reclassify intra-aortic balloon and control system (IABP) devices when indicated for acute coronary syndrome, cardiac and non-cardiac surgery, or complications of heart failure, a preamendments class III device, into class II (special controls), and to require the filing of a premarket approval application (PMA) or a notice of completion of a product development protocol (PDP) for IABPs when indicated for septic shock or pulsatile flow generation. PMID:24383147

  13. Artificial photosynthesis for solar water-splitting

    NASA Astrophysics Data System (ADS)

    Tachibana, Yasuhiro; Vayssieres, Lionel; Durrant, James R.

    2012-08-01

    Hydrogen generated from solar-driven water-splitting has the potential to be a clean, sustainable and abundant energy source. Inspired by natural photosynthesis, artificial solar water-splitting devices are now being designed and tested. Recent developments based on molecular and/or nanostructure designs have led to advances in our understanding of light-induced charge separation and subsequent catalytic water oxidation and reduction reactions. Here we review some of the recent progress towards developing artificial photosynthetic devices, together with their analogies to biological photosynthesis, including technologies that focus on the development of visible-light active hetero-nanostructures and require an understanding of the underlying interfacial carrier dynamics. Finally, we propose a vision for a future sustainable hydrogen fuel community based on artificial photosynthesis.

  14. Design and manufacture of a polyvinyl alcohol (PVA) cryogel tri-leaflet heart valve prosthesis.

    PubMed

    Jiang, Hongjun; Campbell, Gord; Boughner, Derek; Wan, Wan-Kei; Quantz, Mackenzie

    2004-05-01

    Although current artificial heart valves are life sustaining medical devices, improvements are still necessary to address deficiencies. Bioprosthetic valves have a compromised fatigue life, while mechanical valves have better durability but are prone to thromboembolic complications. A novel, one-piece, tricuspid valve, consisting of leaflets, stent and sewing ring, made entirely from the hydrogel, polyvinyl alcohol cryogel (PVA-C), has been developed and demonstrated. This valve has three thin leaflets attached to a cylindrical stent. In order to approximate the complex shape of the surface of the natural heart valve leaflets, two different geometries have been proposed: revolution about an axis of a hyperboloid shape and revolution about an axis of an arc subtending (joining) two straight lines. The parameters of both geometries were examined based on a compromise between avoiding sharp curvature of leaflets and minimization of the central opening of the valve when closed. The revolution of an arc subtending two straight lines was selected as the preferred geometry since it has the benefit of a smaller central opening when the value of the maximum curvature for the leaflets is the same for each valve geometry. A cavity mold has been designed and constructed to form the PVA-C heart valve. The three leaflets were formed and integrated into the stent and sewing ring in a single process. Prototype heart valves were manufactured in the mold from a solution of PVA and water, by controlled freezing and thawing cycles. PMID:15121052

  15. Heart Truth

    MedlinePlus

    ... about women’s risk for heart disease―the #1 killer of women in the United States―and share ... t Care What You Wear—It's the #1 Killer of Women ® are registered trademarks of U.S. ...

  16. Pulsatility flow around a single cylinder - an experimental model of flow inside an artificial lung

    NASA Astrophysics Data System (ADS)

    Lin, Yu-Chun; Bull, Joseph L.

    2004-11-01

    Pulsatile flow past a single cylinder is experimentally investigated using particle image velocimetry. This study aims to elucidate the effects of pulstility on the velocity field, which influences the convection-dominated transport within the fluid. The artificial lung device can be connected in parallel or series with the native lungs and may potentially be used as a bridge to transplant or for pulmonary replacement. The artificial lung consists of hollow microfibers through which gas flows and blood flows around. Blood flow through the device is pulsatile because it is driven entirely by the right heart. Steady flow over bluff bodies has been investigated in many contexts, such as heat exchangers. However, few studies have been investigated the effect of pulsatility. The effects of frequency, amplitude of pulsatility, and average flow rate on the formation of vortices after a cylinder are examined. Vortices near the cylinder are found to develop at lower Reynolds number in pulsatile flow than in steady flow. This work is supported by NIH grant R01 HL69420-01.

  17. 2013 update on congenital heart disease, clinical cardiology, heart failure, and heart transplant.

    PubMed

    Subirana, M Teresa; Barón-Esquivias, Gonzalo; Manito, Nicolás; Oliver, José M; Ripoll, Tomás; Lambert, Jose Luis; Zunzunegui, José L; Bover, Ramon; García-Pinilla, José Manuel

    2014-03-01

    This article presents the most relevant developments in 2013 in 3 key areas of cardiology: congenital heart disease, clinical cardiology, and heart failure and transplant. Within the area of congenital heart disease, we reviewed contributions related to sudden death in adult congenital heart disease, the importance of specific echocardiographic parameters in assessing the systemic right ventricle, problems in patients with repaired tetralogy of Fallot and indication for pulmonary valve replacement, and confirmation of the role of specific factors in the selection of candidates for Fontan surgery. The most recent publications in clinical cardiology include a study by a European working group on correct diagnostic work-up in cardiomyopathies, studies on the cost-effectiveness of percutaneous aortic valve implantation, a consensus document on the management of type B aortic dissection, and guidelines on aortic valve and ascending aortic disease. The most noteworthy developments in heart failure and transplantation include new American guidelines on heart failure, therapeutic advances in acute heart failure (serelaxin), the management of comorbidities such as iron deficiency, risk assessment using new biomarkers, and advances in ventricular assist devices.

  18. Update on heart failure, heart transplant, congenital heart disease, and clinical cardiology.

    PubMed

    Almenar, Luis; Zunzunegui, José Luis; Barón, Gonzalo; Carrasco, José Ignacio; Gómez-Doblas, Juan José; Comín, Josep; Barrios, Vivencio; Subirana, M Teresa; Díaz-Molina, Beatriz

    2013-04-01

    In the year 2012, 3 scientific sections-heart failure and transplant, congenital heart disease, and clinical cardiology-are presented together in the same article. The most relevant development in the area of heart failure and transplantation is the 2012 publication of the European guidelines for heart failure. These describe new possibilities for some drugs (eplerenone and ivabradine); expand the criteria for resynchronization, ventricular assist, and peritoneal dialysis; and cover possibilities of percutaneous repair of the mitral valve (MitraClip(®)). The survival of children with hypoplastic left heart syndrome in congenital heart diseases has improved significantly. Instructions for percutaneous techniques and devices have been revised and modified for the treatment of atrial septal defects, ostium secundum, and ventricular septal defects. Hybrid procedures for addressing structural congenital heart defects have become more widespread. In the area of clinical cardiology studies have demonstrated that percutaneous prosthesis implantation has lower mortality than surgical implantation. Use of the CHA2DS2-VASc criteria and of new anticoagulants (dabigatran, rivaroxaban and apixaban) is also recommended. In addition, the development of new sequencing techniques has enabled the analysis of multiple genes.

  19. About Heart Attacks

    MedlinePlus

    ... survive. A heart attack occurs when the blood flow that brings oxygen to the heart muscle is severely reduced or ... survive. A heart attack occurs when the blood flow that brings oxygen to the heart muscle is severely reduced or ...

  20. Pediatric heart surgery

    MedlinePlus

    Heart surgery - pediatric; Heart surgery for children; Acquired heart disease; Heart valve surgery - children ... after the baby is born. For others, your child may be able to safely wait for months ...

  1. Coronary heart disease

    MedlinePlus

    Heart disease, Coronary heart disease, Coronary artery disease; Arteriosclerotic heart disease; CHD; CAD ... down or stop. A risk factor for heart disease is something that increases your chance of getting ...

  2. Heart disease - resources

    MedlinePlus

    Resources - heart disease ... The following organizations are good resources for information on heart disease: American Heart Association -- www.heart.org Centers for Disease Control and Prevention -- www.cdc.gov/heartdisease

  3. A simple numerical model for membrane oxygenation of an artificial lung machine

    NASA Astrophysics Data System (ADS)

    Subraveti, Sai Nikhil; Sai, P. S. T.; Viswanathan Pillai, Vinod Kumar; Patnaik, B. S. V.

    2015-11-01

    Optimal design of membrane oxygenators will have far reaching ramification in the development of artificial heart-lung systems. In the present CFD study, we simulate the gas exchange between the venous blood and air that passes through the hollow fiber membranes on a benchmark device. The gas exchange between the tube side fluid and the shell side venous liquid is modeled by solving mass, momentum conservation equations. The fiber bundle was modelled as a porous block with a bundle porosity of 0.6. The resistance offered by the fiber bundle was estimated by the standard Ergun correlation. The present numerical simulations are validated against available benchmark data. The effect of bundle porosity, bundle size, Reynolds number, non-Newtonian constitutive relation, upstream velocity distribution etc. on the pressure drop, oxygen saturation levels etc. are investigated. To emulate the features of gas transfer past the alveoli, the effect of pulsatility on the membrane oxygenation is also investigated.

  4. Pulsatile Flow Across a Cylinder--An Investigation of Flow in a Total Artificial Lung

    NASA Astrophysics Data System (ADS)

    Lin, Yu-Chun

    2005-11-01

    The effect of pulsatility on flow across a single cylinder has been examined experimentally using particle image velocimetry. This work is motivated by the ongoing development of a total artificial lung (TAL), a device which would serve as a bridge to lung transplant. The prototype TAL consists of hollow microfibers through which oxygen-rich gas flows and blood flows around. Flow through the device is provided entirely by right heart and, therefore, is puslatile. The Peclet number of the flow is large and consequently the development of secondary flow affects the resulting gas exchange. The effects of frequency and average flow rate of pulsatile flow around a cylinder were investigated experimentally in a water tunnel and some of the results were compared with preliminary numerical results. Vortices developed behind the cylinder at lower Reynolds numbers in pulsatile flow than steady flow. The results indicate that there are critical values of the Reynolds number between 3 to 5 and Stokes numbers of 0.22, below which vortices were not observed. The findings suggest that higher Stokes and Reynolds numbers within the device could enhance vortex formation. However, this enhanced gas exchange could be at the expense of higher device resistance and increased likelihood of blood trauma. Intelligent TAL design will require consideration of these effects. This work is supported by NIH grant HL69420.

  5. The Flow Field Inside Ventricle Assist Device

    NASA Astrophysics Data System (ADS)

    Einav, Shmuel; Rosenfeld, Moshe; Avrahami, Idit

    2000-11-01

    The evaluation of innovative ventricle assist devices (VAD), is of major importance. A New Left Heart Assist Device, with an improved energy converter unit, has been investigated both numerically and experimentally. For this purpose, an experimental Continuous Digital Particle Imagining Velocimetry (CDPIV) is combined with a computational fluid dynamics (CFD) analysis. These tools complement each other to result into a comprehensive description of the complex 3D, viscous and time-dependent flow field inside the artificial ventricle. A 3D numerical model was constructed to simulate the VAD pump and a time-depended CFD analysis with moving walls was performed to predict the flow behaviour in the VAD during the cardiac cycle. A commercial finite element package was used to solve the Navier-Stokes equations (FIDAP, Fluent Inc., Evanston). In the experimental analysis, an optically clear elastic model of the VAD was placed inside a 2D CDPIV system. The CDPIV system is capable of sampling 15 velocity vector fields per second based on image-pairs intervals lower than 0.5 millisecond. Continuous sequences of experimental images, followed by their calculated velocity transient fields, are given as animated presentation of the distensible VAD. These results are used for validating the CFD simulations. Once validated, the CFD results provide a detailed 3D and time dependent description of the flow field, allowing the identification of stagnation or high shear stress regions.

  6. Mechanical circulatory support in heart failure.

    PubMed

    Szyguła-Jurkiewicz, Bożena; Szczurek, Wioletta; Suliga, Kamil; Rempega, Grzegorz; Rajwa, Paweł

    2016-06-01

    The increasing number of end-stage heart failure patients eligible for heart transplant and the disproportionately low number of donor hearts have led to increased interest in ventricular assist devices (VAD). These devices can be used as a bridge to decision, bridge to recovery, or bridge to candidacy. The main advantage of mechanical circulatory support (MCS) is the improvement of organ perfusion and function, which leads to better quality of life and survival. The MCS can also be used as a destination therapy in end-stage heart failure patients who are not eligible for heart transplant. It should be remembered that, despite the tangible benefits, VAD implantation may also be associated with the risk of serious complications, such as bleeding, infection, arrhythmias, blood clots, right ventricular failure, and cardiovascular events. This study presents an up-to-date overview of the current knowledge on the role of MCS in modern medicine. PMID:27516785

  7. Mechanical circulatory support in heart failure

    PubMed Central

    Szczurek, Wioletta; Suliga, Kamil; Rempega, Grzegorz; Rajwa, Paweł

    2016-01-01

    The increasing number of end-stage heart failure patients eligible for heart transplant and the disproportionately low number of donor hearts have led to increased interest in ventricular assist devices (VAD). These devices can be used as a bridge to decision, bridge to recovery, or bridge to candidacy. The main advantage of mechanical circulatory support (MCS) is the improvement of organ perfusion and function, which leads to better quality of life and survival. The MCS can also be used as a destination therapy in end-stage heart failure patients who are not eligible for heart transplant. It should be remembered that, despite the tangible benefits, VAD implantation may also be associated with the risk of serious complications, such as bleeding, infection, arrhythmias, blood clots, right ventricular failure, and cardiovascular events. This study presents an up-to-date overview of the current knowledge on the role of MCS in modern medicine. PMID:27516785

  8. In vitro heart valve testing: steady versus pulsatile flow.

    PubMed

    Black, M M; Hose, D R; Lamb, C J; Lawford, P V; Ralph, S J

    1994-03-01

    The design of artificial heart valves has traditionally been based on the development of a prototype device which was then subjected to extensive laboratory testing in order to confirm its suitability for clinical use. In the past the in vitro assessment of a valve's performance was based principally on the measurement of parameters such as pressure difference, regurgitation and, more recently, energy losses. Such measurements can be defined as being at the 'macro' level and rarely show any clinically significant differences amongst currently available prostheses. The analytical approach to flow through heart valves has previously been hampered by difficulties experienced in solving the relevant equations of flow particularly in the case of pulsatile conditions. Computational techniques are now available which enable appropriate solutions to be obtained for these problems and consequently provide an opportunity for detailed examination of the 'micro' level of flow disturbances exhibited by the different valves. This present preliminary study is designed to illustrate the use of such an analytical approach to the flow through prosthetic valves. A single topic has been selected for this purpose which is the comparative value of steady versus pulsatile flow testing. A bileaflet valve was chosen for the analysis and a mathematical model of this valve in the aortic position of the Sheffield Pulse Duplicator was created. The theoretical analysis was carried out using a commercially available Computational Fluid Dynamics package, namely, FIDAP, on a SUN MICROSYSTEMS 10-30 workstation.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Self-assembled artificial cilia

    PubMed Central

    Vilfan, Mojca; Potočnik, Anton; Kavčič, Blaž; Osterman, Natan; Poberaj, Igor; Vilfan, Andrej; Babič, Dušan

    2010-01-01

    Due to their small dimensions, microfluidic devices operate in the low Reynolds number regime. In this case, the hydrodynamics is governed by the viscosity rather than inertia and special elements have to be introduced into the system for mixing and pumping of fluids. Here we report on the realization of an effective pumping device that mimics a ciliated surface and imitates its motion to generate fluid flow. The artificial biomimetic cilia are constructed as long chains of spherical superparamagnetic particles, which self-assemble in an external magnetic field. Magnetic field is also used to actuate the cilia in a simple nonreciprocal manner, resulting in a fluid flow. We prove the concept by measuring the velocity of a cilia-pumped fluid as a function of height above the ciliated surface and investigate the influence of the beating asymmetry on the pumping performance. A numerical simulation was carried out that successfully reproduced the experimentally obtained data. PMID:19934055

  10. Bioinspired artificial single ion pump.

    PubMed

    Zhang, Huacheng; Hou, Xu; Zeng, Lu; Yang, Fu; Li, Lin; Yan, Dadong; Tian, Ye; Jiang, Lei

    2013-10-30

    Bioinspired artificial functional nanochannels for intelligent molecular and ionic transport control at the nanoscale have wide potential applications in nanofluidics, energy conversion, and biosensors. Although various smart passive ion transport properties of ion channels have been artificially realized, it is still hugely challenging to achieve high level intelligent ion transport features in biological ion pumps. Here we show a unique bioinspired single ion pump based on a cooperative pH response double-gate nanochannel, whose gates could be opened and closed alternately/simultaneously under symmetric/asymmetric pH environments. With the stimulation of the double-gate nanochannel by continuous switching of the symmetric/asymmetric pH stimuli, the bioinspired system systematically realized three key ionic transport features of biological ion pumps, including an alternating gates ion pumping process under symmetric pH stimuli, transformation of the ion pump into an ion channel under asymmetric pH stimuli, and a fail-safe ion pumping feature under both symmetric and asymmetric pH stimuli. The ion pumping processes could well be reproduced under a concentration gradient. With the advantages of the extraordinary ionic transport functions of biological ion pumps, the bioinspired ion pump should find widespread applicability in active transportation-controlling smart nanofluidic devices, efficient energy conversions, and seawater desalinization, and open the way to design and develop novel bioinspired intelligent artificial nanochannel materials.

  11. Bioinspired artificial single ion pump.

    PubMed

    Zhang, Huacheng; Hou, Xu; Zeng, Lu; Yang, Fu; Li, Lin; Yan, Dadong; Tian, Ye; Jiang, Lei

    2013-10-30

    Bioinspired artificial functional nanochannels for intelligent molecular and ionic transport control at the nanoscale have wide potential applications in nanofluidics, energy conversion, and biosensors. Although various smart passive ion transport properties of ion channels have been artificially realized, it is still hugely challenging to achieve high level intelligent ion transport features in biological ion pumps. Here we show a unique bioinspired single ion pump based on a cooperative pH response double-gate nanochannel, whose gates could be opened and closed alternately/simultaneously under symmetric/asymmetric pH environments. With the stimulation of the double-gate nanochannel by continuous switching of the symmetric/asymmetric pH stimuli, the bioinspired system systematically realized three key ionic transport features of biological ion pumps, including an alternating gates ion pumping process under symmetric pH stimuli, transformation of the ion pump into an ion channel under asymmetric pH stimuli, and a fail-safe ion pumping feature under both symmetric and asymmetric pH stimuli. The ion pumping processes could well be reproduced under a concentration gradient. With the advantages of the extraordinary ionic transport functions of biological ion pumps, the bioinspired ion pump should find widespread applicability in active transportation-controlling smart nanofluidic devices, efficient energy conversions, and seawater desalinization, and open the way to design and develop novel bioinspired intelligent artificial nanochannel materials. PMID:23773031

  12. Wireless quantified reflex device

    NASA Astrophysics Data System (ADS)

    Lemoyne, Robert Charles

    The deep tendon reflex is a fundamental aspect of a neurological examination. The two major parameters of the tendon reflex are response and latency, which are presently evaluated qualitatively during a neurological examination. The reflex loop is capable of providing insight for the status and therapy response of both upper and lower motor neuron syndromes. Attempts have been made to ascertain reflex response and latency, however these systems are relatively complex, resource intensive, with issues of consistent and reliable accuracy. The solution presented is a wireless quantified reflex device using tandem three dimensional wireless accelerometers to obtain response based on acceleration waveform amplitude and latency derived from temporal acceleration waveform disparity. Three specific aims have been established for the proposed wireless quantified reflex device: 1. Demonstrate the wireless quantified reflex device is reliably capable of ascertaining quantified reflex response and latency using a quantified input. 2. Evaluate the precision of the device using an artificial reflex system. 3.Conduct a longitudinal study respective of subjects with healthy patellar tendon reflexes, using the wireless quantified reflex evaluation device to obtain quantified reflex response and latency. Aim 1 has led to the steady evolution of the wireless quantified reflex device from a singular two dimensional wireless accelerometer capable of measuring reflex response to a tandem three dimensional wireless accelerometer capable of reliably measuring reflex response and latency. The hypothesis for aim 1 is that a reflex quantification device can be established for reliably measuring reflex response and latency for the patellar tendon reflex, comprised of an integrated system of wireless three dimensional MEMS accelerometers. Aim 2 further emphasized the reliability of the wireless quantified reflex device by evaluating an artificial reflex system. The hypothesis for aim 2 is that

  13. [Implantable hemodynamic monitoring devices].

    PubMed

    Seifert, M; Butter, C

    2015-11-01

    Heart failure is one of the most frequent diagnoses in hospital admissions in Germany. In the majority of these admissions acute decompensation of an already existing chronic heart failure is responsible. New mostly wireless and remote strategies for monitoring, titration, adaptation and optimization are the focus for improvement of the treatment of heart failure patients and the poor prognosis. The implantation of hemodynamic monitoring devices follows the hypothesis that significant changes in hemodynamic parameters occur before the occurrence of acute decompensation requiring readmission. Three different hemodynamic monitoring devices have so far been investigated in clinical trials employing right ventricular pressure, left atrial pressure and pulmonary artery pressure monitoring. Only one of these systems, the CardioMENS™ HF monitoring system, demonstrated a significant reduction of hospitalization due to heart failure over 6 months in the CHAMPION trial. The systematic adaptation of medication in the CHAMPION trial significantly differed from the usual care of the control arm over 6 months. This direct day to day management of diuretics is currently under intensive investigation; however, further studies demonstrating a positive effect on mortality are needed before translation of this approach into guidelines. Without this evidence a further implementation of pressure monitoring into currently used devices and justification of the substantial technical and personnel demands are not warranted.

  14. 21 CFR 872.3910 - Backing and facing for an artificial tooth.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Backing and facing for an artificial tooth. 872... artificial tooth. (a) Identification. A backing and facing for an artificial tooth is a device intended for..., which is made of gold, is attached to the dental appliance and supports the tooth-colored facing,...

  15. 21 CFR 872.3910 - Backing and facing for an artificial tooth.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Backing and facing for an artificial tooth. 872... artificial tooth. (a) Identification. A backing and facing for an artificial tooth is a device intended for..., which is made of gold, is attached to the dental appliance and supports the tooth-colored facing,...

  16. 21 CFR 872.3910 - Backing and facing for an artificial tooth.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Backing and facing for an artificial tooth. 872... artificial tooth. (a) Identification. A backing and facing for an artificial tooth is a device intended for..., which is made of gold, is attached to the dental appliance and supports the tooth-colored facing,...

  17. An artificial muscle computer

    NASA Astrophysics Data System (ADS)

    Marc O'Brien, Benjamin; Alexander Anderson, Iain

    2013-03-01

    We have built an artificial muscle computer based on Wolfram's "2, 3" Turing machine architecture, the simplest known universal Turing machine. Our computer uses artificial muscles for its instruction set, output buffers, and memory write and addressing mechanisms. The computer is very slow and large (0.15 Hz, ˜1 m3); however by using only 13 artificial muscle relays, it is capable of solving any computable problem given sufficient memory, time, and reliability. The development of this computer shows that artificial muscles can think—paving the way for soft robots with reflexes like those seen in nature.

  18. Energy conversion in natural and artificial photosynthesis.

    PubMed

    McConnell, Iain; Li, Gonghu; Brudvig, Gary W

    2010-05-28

    Modern civilization is dependent upon fossil fuels, a nonrenewable energy source originally provided by the storage of solar energy. Fossil-fuel dependence has severe consequences, including energy security issues and greenhouse gas emissions. The consequences of fossil-fuel dependence could be avoided by fuel-producing artificial systems that mimic natural photosynthesis, directly converting solar energy to fuel. This review describes the three key components of solar energy conversion in photosynthesis: light harvesting, charge separation, and catalysis. These processes are compared in natural and in artificial systems. Such a comparison can assist in understanding the general principles of photosynthesis and in developing working devices, including photoelectrochemical cells, for solar energy conversion.

  19. Energy Conversion in Natural and Artificial Photosynthesis

    PubMed Central

    McConnell, Iain; Li, Gonghu; Brudvig, Gary W.

    2010-01-01

    Summary Modern civilization is dependent upon fossil fuels, a nonrenewable energy source originally provided by the storage of solar energy. Fossil fuel dependence has severe consequences including energy security issues and greenhouse gas emissions. The consequences of fossil fuel dependence could be avoided by fuel-producing artificial systems that mimic natural photosynthesis, directly converting solar energy to fuel. This review describes the three key components of solar energy conversion in photosynthesis: light harvesting, charge separation, and catalysis. These processes are compared in natural and artificial systems. Such a comparison can assist in understanding the general principles of photosynthesis and in developing working devices including photoelectrochemical cells for solar energy conversion. PMID:20534342

  20. Optimization of Centrifugal Pump Characteristic Dimensions for Mechanical Circulatory Support Devices.

    PubMed

    Korakianitis, Theodosios; Rezaienia, Mohammad A; Paul, Gordon M; Rahideh, Akbar; Rothman, Martin T; Mozafari, Sahand

    2016-01-01

    The application of artificial mechanical pumps as heart assist devices impose power and size limitations on the pumping mechanism, and therefore requires careful optimization of pump characteristics. Typically new pumps are designed by relying on the performance of other previously designed pumps of known performance using concepts of fluid dynamic similarity. Such data are readily available for industrial pumps, which operate in Reynolds numbers region of 10. Heart assist pumps operate in Reynolds numbers of 10. There are few data available for the design of centrifugal pumps in this characteristic range. This article develops specific speed versus specific diameter graphs suitable for the design and optimization of these smaller centrifugal pumps concentrating in dimensions suitable for ventricular assist devices (VADs) and mechanical circulatory support (MCS) devices. A combination of experimental and numerical techniques was used to measure and analyze the performance of 100 optimized pumps designed for this application. The data are presented in the traditional Cordier diagram of nondimensional specific speed versus specific diameter. Using these data, nine efficient designs were selected to be manufactured and tested in different operating conditions of flow, pressure, and rotational speed. The nondimensional results presented in this article enable preliminary design of centrifugal pumps for VADs and MCS devices. PMID:27258221

  1. Optimization of Centrifugal Pump Characteristic Dimensions for Mechanical Circulatory Support Devices.

    PubMed

    Korakianitis, Theodosios; Rezaienia, Mohammad A; Paul, Gordon M; Rahideh, Akbar; Rothman, Martin T; Mozafari, Sahand

    2016-01-01

    The application of artificial mechanical pumps as heart assist devices impose power and size limitations on the pumping mechanism, and therefore requires careful optimization of pump characteristics. Typically new pumps are designed by relying on the performance of other previously designed pumps of known performance using concepts of fluid dynamic similarity. Such data are readily available for industrial pumps, which operate in Reynolds numbers region of 10. Heart assist pumps operate in Reynolds numbers of 10. There are few data available for the design of centrifugal pumps in this characteristic range. This article develops specific speed versus specific diameter graphs suitable for the design and optimization of these smaller centrifugal pumps concentrating in dimensions suitable for ventricular assist devices (VADs) and mechanical circulatory support (MCS) devices. A combination of experimental and numerical techniques was used to measure and analyze the performance of 100 optimized pumps designed for this application. The data are presented in the traditional Cordier diagram of nondimensional specific speed versus specific diameter. Using these data, nine efficient designs were selected to be manufactured and tested in different operating conditions of flow, pressure, and rotational speed. The nondimensional results presented in this article enable preliminary design of centrifugal pumps for VADs and MCS devices.

  2. Biomedical materials and devices

    SciTech Connect

    Hanker, J. S. ); Giammara, B. L. )

    1989-01-01

    This conference reports on how biomedical materials and devices are undergoing important changes that require interdisciplinary approaches, innovation expertise, and access to sophisticated preparative and analytical equipment and methodologies. The interaction of materials scientists with biomedical, biotechnological, bioengineering and clinical scientists in the last decade has resulted in major advances in therapy. New therapeutic modalities and bioengineering methods and devices for the continuous removal of toxins or pathologic products present in arthritis, atherosclerosis and malignancy are presented. Novel monitoring and controlled drug delivery systems and discussions of materials such as blood or plasma substitutes, artificial organs, and bone graft substitutes are discussed.

  3. Geometry and Cloaking Devices

    NASA Astrophysics Data System (ADS)

    Ochiai, T.; Nacher, J. C.

    2011-09-01

    Recently, the application of geometry and conformal mappings to artificial materials (metamaterials) has attracted the attention in various research communities. These materials, characterized by a unique man-made structure, have unusual optical properties, which materials found in nature do not exhibit. By applying the geometry and conformal mappings theory to metamaterial science, it may be possible to realize so-called "Harry Potter cloaking device". Although such a device is still in the science fiction realm, several works have shown that by using such metamaterials it may be possible to control the direction of the electromagnetic field at will. We could then make an object hidden inside of a cloaking device. Here, we will explain how to design invisibility device using differential geometry and conformal mappings.

  4. Polarimetric glucose sensing in an artificial eye anterior chamber

    NASA Astrophysics Data System (ADS)

    Malik, Bilal H.; Pirnstill, Casey W.; Coté, Gerard L.

    2012-03-01

    The application of optical polarimetry to glucose sensing in the anterior chamber of the eye has emerged as a potential technique to noninvasively ascertain blood glucose levels. One of the major limiting factors preventing the realization of such a device is the time varying corneal birefringence due to motion artifact in the eye. The varying birefringence confounds the optical activity of glucose, and thus, needs to be taken into account in order to successfully predict the glucose concentration in the aqueous humor of the eye. Our group has developed a multi-spectral optical polarimetric approach which can minimize the effect of corneal birefringence coupled with motion artifact by treating it as common mode noise to multiple wavelengths. Here, we present the application of a real-time closed-loop dual wavelength polarimeter to ex vivo glucose sensing in excised New Zealand White rabbits' corneas mounted on an artificial anterior chamber. Our PID control system can reach stability in less than 100 ms which is fast enough to overcome motion artifact due to heart beat and respiration. The system can predict the glucose concentration with a standard error of less than 26 mg/dL in the physiologic glucose range of 0 - 500 mg/dL. Our results indicate that dualwavelength polarimetry has the potential to noninvasively probe glucose through the anterior chamber of the eye.

  5. Left Ventricular Assist Devices

    PubMed Central

    2004-01-01

    Executive Summary Objective The objective of this health technology policy assessment was to determine the effectiveness and cost-effectiveness of using implantable ventricular assist devices in the treatment of end-stage heart failure. Heart Failure Heart failure is a complex syndrome that impairs the ability of the heart to maintain adequate blood circulation, resulting in multiorgan abnormalities and, eventually, death. In the period of 1994 to 1997, 38,702 individuals in Ontario had a first hospital admission for heart failure. Despite reported improvement in survival, the five-year mortality rate for heart failure is about 50%. For patients with end-stage heart failure that does not respond to medical therapy, surgical treatment or traditional circulatory assist devices, heart transplantation (in appropriate patients) is the only treatment that provides significant patient benefit. Heart Transplant in Ontario With a shortage in the supply of donor hearts, patients are waiting longer for a heart transplant and may die before a donor heart is available. From 1999 to 2003, 55 to 74 people received a heart transplant in Ontario each year. Another 12 to 21 people died while waiting for a suitable donor heart. Of these, 1 to 5 deaths occurred in people under 18 years old. The rate-limiting factor in heart transplant is the supply of donor hearts. Without an increase in available donor hearts, attempts at prolonging the life of some patients on the transplant wait list could have a harmful effect on other patients that are being pushed down the waiting list (knock on effect). LVAD Technology Ventricular assist devices [VADs] have been developed to provide circulatory assistance to patients with end-stage heart failure. These are small pumps that usually assist the damaged left ventricle [LVADs] and may be situated within the body (intracorporeal] or outside the body [extracorporeal). Some of these devices were designed for use in the right ventricle [RVAD] or both

  6. Theory underlying the peripheral vision horizon device

    NASA Technical Reports Server (NTRS)

    Money, K. E.

    1984-01-01

    Peripheral Vision Horizon Device (PVHD) theory states that the likelihood of pilot disorientation in flight is reduced by providing an artificial horizon that provides orientation information to peripheral vision. In considering the validity of the theory, three areas are explored: the use of an artificial horizon device over some other flight instrument; the use of peripheral vision over foveal vision; and the evidence that peripheral vision is well suited to the processing of orientation information.

  7. Artificial insemination in poultry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Artificial insemination is a relative simple yet powerful tool geneticists can employ for the propagation of economically important traits in livestock and poultry. In this chapter, we address the fundamental methods of the artificial insemination of poultry, including semen collection, semen evalu...

  8. Artificial intelligence: Recent developments

    SciTech Connect

    Not Available

    1987-01-01

    This book presents the papers given at a conference on artificial intelligence. Topics considered at the conference included knowledge representation for expert systems, the use of robots in underwater vehicles for resource management, precision logic, an expert system for arc welding, data base management, a knowledge based approach to fault trees, and computer-aided manufacturing using simulation combined with artificial intelligence.

  9. Willem J Kolff (1911-2009): physician, inventor and pioneer: father of artificial organs.

    PubMed

    Morrissey, Megan

    2012-08-01

    Medical pioneer Willem Johan Kolff was an inspirational father, son, physician and inventor. He founded the development of the first kidney dialysis machine, pioneered advances in the heart and lung machine, laid down the foundations for the first mainland blood bank in Europe and successfully implanted the first artificial heart into humans.

  10. Onion artificial muscles

    NASA Astrophysics Data System (ADS)

    Chen, Chien-Chun; Shih, Wen-Pin; Chang, Pei-Zen; Lai, Hsi-Mei; Chang, Shing-Yun; Huang, Pin-Chun; Jeng, Huai-An

    2015-05-01

    Artificial muscles are soft actuators with the capability of either bending or contraction/elongation subjected to external stimulation. However, there are currently no artificial muscles that can accomplish these actions simultaneously. We found that the single layered, latticed microstructure of onion epidermal cells after acid treatment became elastic and could simultaneously stretch and bend when an electric field was applied. By modulating the magnitude of the voltage, the artificial muscle made of onion epidermal cells would deflect in opposing directions while either contracting or elongating. At voltages of 0-50 V, the artificial muscle elongated and had a maximum deflection of -30 μm; at voltages of 50-1000 V, the artificial muscle contracted and deflected 1.0 mm. The maximum force response is 20 μN at 1000 V.

  11. Accuracy of Heart Rate Watches: Implications for Weight Management

    PubMed Central

    2016-01-01

    Background Wrist-worn monitors claim to provide accurate measures of heart rate and energy expenditure. People wishing to lose weight use these devices to monitor energy balance, however the accuracy of these devices to measure such parameters has not been established. Aim To determine the accuracy of four wrist-worn devices (Apple Watch, Fitbit Charge HR, Samsung Gear S and Mio Alpha) to measure heart rate and energy expenditure at rest and during exercise. Methods Twenty-two healthy volunteers (50% female; aged 24 ± 5.6 years) completed ~1-hr protocols involving supine and seated rest, walking and running on a treadmill and cycling on an ergometer. Data from the devices collected during the protocol were compared with reference methods: electrocardiography (heart rate) and indirect calorimetry (energy expenditure). Results None of the devices performed significantly better overall, however heart rate was consistently more accurate than energy expenditure across all four devices. Correlations between the devices and reference methods were moderate to strong for heart rate (0.67–0.95 [0.35 to 0.98]) and weak to strong for energy expenditure (0.16–0.86 [-0.25 to 0.95]). All devices underestimated both outcomes compared to reference methods. The percentage error for heart rate was small across the devices (range: 1–9%) but greater for energy expenditure (9–43%). Similarly, limits of agreement were considerably narrower for heart rate (ranging from -27.3 to 13.1 bpm) than energy expenditure (ranging from -266.7 to 65.7 kcals) across devices. Conclusion These devices accurately measure heart rate. However, estimates of energy expenditure are poor and would have implications for people using these devices for weight loss. PMID:27232714

  12. How the Heart Works

    MedlinePlus

    ... for the Public » Health Topics » How the Heart Works Explore How the Heart Works What Is... Anatomy Contraction Circulation Electrical System Heart ... Heart Disease Heart Valve Disease How the Lungs Work Send a link to NHLBI to someone by ...

  13. Heart Health for Women

    MedlinePlus

    ... signs of a heart attack. 1. Eat a heart healthy diet. The nutrition facts on the food label can help you make ... heart health for women . (PDF 190KB) Get the facts about heart attacks in women . Learn More About Heart Disease: ...

  14. An alien in the heart.

    PubMed

    Agrawal, Yashwant; Kalavakunta, Jagadeesh K; Gupta, Vishal

    2016-07-01

    We report a case of a 38-year-old-man who presented with altered mental status. The patient was diagnosed with infective endocarditis (IE) originating from the GORE HELEX septal occluder device, which was placed 15 months earlier for symptomatic atrial septal defect. Brain imaging revealed shower emboli phenomena from the known IE. The patient developed hydrocephalus for which external ventriculostomy was performed. Improved neurological status warranted open heart surgery. The patient was later confirmed to be an intravenous drugs abuser, prejudicing IE. This case highlights the importance of meticulously monitoring patients with suspected high-risk behavior with an implanted intracardiac prosthetic device. PMID:27358534

  15. Artificial intelligence in medicine.

    PubMed Central

    Ramesh, A. N.; Kambhampati, C.; Monson, J. R. T.; Drew, P. J.

    2004-01-01

    INTRODUCTION: Artificial intelligence is a branch of computer science capable of analysing complex medical data. Their potential to exploit meaningful relationship with in a data set can be used in the diagnosis, treatment and predicting outcome in many clinical scenarios. METHODS: Medline and internet searches were carried out using the keywords 'artificial intelligence' and 'neural networks (computer)'. Further references were obtained by cross-referencing from key articles. An overview of different artificial intelligent techniques is presented in this paper along with the review of important clinical applications. RESULTS: The proficiency of artificial intelligent techniques has been explored in almost every field of medicine. Artificial neural network was the most commonly used analytical tool whilst other artificial intelligent techniques such as fuzzy expert systems, evolutionary computation and hybrid intelligent systems have all been used in different clinical settings. DISCUSSION: Artificial intelligence techniques have the potential to be applied in almost every field of medicine. There is need for further clinical trials which are appropriately designed before these emergent techniques find application in the real clinical setting. PMID:15333167

  16. Artificial intelligence in medicine: the challenges ahead.

    PubMed Central

    Coiera, E W

    1996-01-01

    The modern study of artificial intelligence in medicine (AIM) is 25 years old. Throughout this period, the field has attracted many of the best computer scientists, and their work represents a remarkable achievement. However, AIM has not been successful-if success is judged as making an impact on the practice of medicine. Much recent work in AIM has been focused inward, addressing problems that are at the crossroads of the parent disciplines of medicine and artificial intelligence. Now, AIM must move forward with the insights that it has gained and focus on finding solutions for problems at the heart of medical practice. The growing emphasis within medicine on evidence-based practice should provide the right environment for that change. PMID:8930853

  17. Heart and Down Syndrome

    MedlinePlus

    ... Associated Conditions » The Heart & Down Syndrome The Heart & Down Syndrome Abnormalities of the cardiovascular system are common in ... the Most Common Heart Defects in Children With Down Syndrome? The most common defects are Atrioventricular Septal Defect ( ...

  18. Heart bypass surgery

    MedlinePlus

    Heart bypass surgery begins with an incision made in the chest, with the breastbone cut exposing the heart. Next, ... of this great vein will be used to bypass the blocked arteries in the heart. The venous ...

  19. Honolulu Heart Program

    ClinicalTrials.gov

    2016-04-13

    Cardiovascular Diseases; Coronary Disease; Cerebrovascular Accident; Heart Diseases; Heart Failure, Congestive; Myocardial Infarction; Asthma; Emphysema; Lung Diseases, Obstructive; Aortic Aneurysm, Abdominal; Bronchitis; Dementia; Hypertension; Chronic Obstructive Pulmonary Disease; Heart Failure

  20. What Causes Heart Failure?

    MedlinePlus

    ... the heart, leading to heart failure. High Blood Pressure Blood pressure is the force of blood pushing against the ... weaken your heart and lead to plaque buildup. Blood pressure is considered high if it stays at or ...

  1. Right heart ventriculography

    MedlinePlus

    Angiography - right heart ... moved forward into the right side of the heart. As the catheter is advanced, the doctor can ... is injected into the right side of the heart. It helps the cardiologist determine the size and ...

  2. Left heart catheterization

    MedlinePlus

    Catheterization - left heart ... to help guide the catheters up into your heart and arteries. Dye will be injected into your ... in the blood vessels that lead to your heart. The catheter is then moved through the aortic ...

  3. Heart Attack Recovery FAQs

    MedlinePlus

    ... Pressure High Blood Pressure Tools & Resources Stroke More Heart Attack Recovery FAQs Updated:Aug 24,2016 Most people ... recovery. View an animation of a heart attack . Heart Attack Recovery Questions and Answers What treatments will I ...

  4. Heart Murmurs (For Kids)

    MedlinePlus

    ... than normal. You also might get an electrocardiogram (EKG), which measures electrical activity of the heart. None ... MORE ON THIS TOPIC The Heart Getting an EKG (Video) Your Heart & Circulatory System Mitral Valve Prolapse ...

  5. Cyanotic heart disease

    MedlinePlus

    ... heart) may be absent or unable to open wide enough. Pulmonary valve (the valve between the heart ... lungs) may be absent or unable to open wide enough . Aortic valve (the valve between the heart ...

  6. Left heart ventricular angiography

    MedlinePlus

    ... through the left side of the heart. Blood volumes and pressures are also normal. ... of the catheter Heart failure due to the volume of the dye Infection Kidney failure from the dye Low blood pressure Heart attack Hemorrhage Stroke

  7. Artificial Photosynthesis with Semiconductor-Liquid Junctions.

    PubMed

    Guijarro, Néstor; Formal, Florian Le; Sivula, Kevin

    2015-01-01

    Given the urgent need to develop a sustainable, carbon neutral energy storage system on a global scale, intense efforts are currently underway to advance the field of artificial photosynthesis: i.e. solar fuel engineering. In this review we give an overview of the field of artificial photosynthesis using a semiconductor-electrolyte interface employed in a photoelectrochemical device or as a heterogeneous photocatalyst. First we present a basic description of the operation principles of a semiconductor-liquid junction based device. The role of nanotechnology in the recent advances in the field is highlighted and common material systems under current study are briefly reviewed. The importance of the material surfaces are further scrutinized by presenting recent advances in interfacial engineering. Technical challenges and an outlook towards industrialization of the technology are given.

  8. Heart Health - Heart Disease: Symptoms, Diagnosis, Treatment

    MedlinePlus

    ... or stomach. Diagnosis Key heart tests include: Electrocardiogram (ECG or EKG) —This records the electrical activity of the heart as it contracts and relaxes. The ECG can detect abnormal heartbeats, some areas of damage, ...

  9. Engineering a Light-Attenuating Artificial Iris

    PubMed Central

    Shareef, Farah J.; Sun, Shan; Kotecha, Mrignayani; Kassem, Iris; Azar, Dimitri; Cho, Michael

    2016-01-01

    Purpose Discomfort from light exposure leads to photophobia, glare, and poor vision in patients with congenital or trauma-induced iris damage. Commercial artificial iris lenses are static in nature to provide aesthetics without restoring the natural iris's dynamic response to light. A new photo-responsive artificial iris was therefore developed using a photochromic material with self-adaptive light transmission properties and encased in a transparent biocompatible polymer matrix. Methods The implantable artificial iris was designed and engineered using Photopia, a class of photo-responsive materials (termed naphthopyrans) embedded in polyethylene. Photopia was reshaped into annular disks that were spin-coated with polydimethylsiloxane (PDMS) to form our artificial iris lens of controlled thickness. Results Activated by UV and blue light in approximately 5 seconds with complete reversal in less than 1 minute, the artificial iris demonstrates graded attenuation of up to 40% of visible and 60% of UV light. There optical characteristics are suitable to reversibly regulate the incident light intensity. In vitro cell culture experiments showed up to 60% cell death within 10 days of exposure to Photopia, but no significant cell death observed when cultured with the artificial iris with protective encapsulation. Nuclear magnetic resonance spectroscopy confirmed these results as there was no apparent leakage of potentially toxic photochromic material from the ophthalmic device. Conclusions Our artificial iris lens mimics the functionality of the natural iris by attenuating light intensity entering the eye with its rapid reversible change in opacity and thus potentially providing an improved treatment option for patients with iris damage. PMID:27116547

  10. Pediatric heart surgery - discharge

    MedlinePlus

    Congenital heart surgery - discharge; Patent ductus arteriosus ligation - discharge; Hypoplastic left heart repair - discharge; Tetralogy of Fallot repair - discharge; Coarctation of the aorta repair - discharge; ...

  11. Heart failure - medicines

    MedlinePlus

    CHF - medicines; Congestive heart failure - medicines; Cardiomyopathy - medicines; HF - medicines ... You will need to take most of your heart failure medicines every day. Some medicines are taken ...

  12. Complex artificial halos for the classroom

    NASA Astrophysics Data System (ADS)

    Selmke, Markus; Selmke, Sarah

    2016-07-01

    Halos represent a common and imposing atmospheric optics phenomenon whose displays are caused by tiny air-borne ice crystals. Their variety stems from a certain set of orientation classes to which these crystals belong. We present a robust and inexpensive device, made of modular components, that allows for the replication of most of these orientation classes in the laboratory. Under the illumination of light, the corresponding artificial halo counterparts emerge. The mechanical realization of this device allows a thorough understanding and demonstration of these beautiful atmospheric optics phenomena.

  13. Artificial Sweeteners and Cancer

    MedlinePlus

    ... artificial sweeteners and cancer? Saccharin Studies in laboratory rats during the early 1970s linked saccharin with the ... cause cancer in laboratory animals .” Subsequent studies in rats showed an increased incidence of urinary bladder cancer ...

  14. Intelligence: Real or artificial?

    PubMed Central

    Schlinger, Henry D.

    1992-01-01

    Throughout the history of the artificial intelligence movement, researchers have strived to create computers that could simulate general human intelligence. This paper argues that workers in artificial intelligence have failed to achieve this goal because they adopted the wrong model of human behavior and intelligence, namely a cognitive essentialist model with origins in the traditional philosophies of natural intelligence. An analysis of the word “intelligence” suggests that it originally referred to behavior-environment relations and not to inferred internal structures and processes. It is concluded that if workers in artificial intelligence are to succeed in their general goal, then they must design machines that are adaptive, that is, that can learn. Thus, artificial intelligence researchers must discard their essentialist model of natural intelligence and adopt a selectionist model instead. Such a strategic change should lead them to the science of behavior analysis. PMID:22477051

  15. Introduction to artificial intelligence

    SciTech Connect

    Charniak, E.; McDermott, D.

    1985-01-01

    This book is an introduction on artificial intelligence. Topics include reasoning under uncertainty, robot plans, language understanding, and learning. The history of the field as well as intellectual ties to related disciplines are presented.

  16. Liver Cell Culture Devices

    PubMed Central

    Andria, B.; Bracco, A.; Cirino, G.; Chamuleau, R. A. F. M.

    2010-01-01

    In the last 15 years many different liver cell culture devices, consisting of functional liver cells and artificial materials, have been developed. They have been devised for numerous different applications, such as temporary organ replacement (a bridge to liver transplantation or native liver regeneration) and as in vitro screening systems in the early stages of the drug development process, like assessing hepatotoxicity, hepatic drug metabolism, and induction/inhibition studies. Relevant literature is summarized about artificial human liver cell culture systems by scrutinizing PubMed from 2003 to 2009. Existing devices are divided in 2D configurations (e.g., static monolayer, sandwich, perfused cells, and flat plate) and 3D configurations (e.g., liver slices, spheroids, and different types of bioreactors). The essential features of an ideal liver cell culture system are discussed: different types of scaffolds, oxygenation systems, extracellular matrixes (natural and artificial), cocultures with nonparenchymal cells, and the role of shear stress problems. Finally, miniaturization and high-throughput systems are discussed. All these factors contribute in their own way to the viability and functionality of liver cells in culture. Depending on the aim for which they are designed, several good systems are available for predicting hepatotoxicity and hepatic metabolism within the general population. To predict hepatotoxicity in individual cases genomic analysis might be essential as well. PMID:26998397

  17. What's happening in artificial lift

    SciTech Connect

    Lea, J.F. ); Winkler, H.W.

    1991-05-01

    New developments reported this year are primarily in the areas of electrical submersible pumps (ESPs), beam pumps, and gas lift. The available information includes new products, techniques for extending run life, controllers, monitors and various other products. Specific topics in this article include: ESP turn key leases for temporary lifting; Horizontal pumps; Gas diffusion coatings for ESP bushings and sleeves; ESP variable rate current-voltage recording monitor; Power tubing ESP status; Low volume, high efficiency ESP stage; ESP improvements for horizontal and abrasive conditions; ESP computer design program effort; Well analyzer; Beam pump controller with variable frequency drive; Hydraulic pumping units; Mobile swab unit for marginal wells; Device for unseating downhole pumps; Gas lift valve test stand; Plunger lift controllers; Resettable ESP packer; Power generation from wellhead gas; and Artificial lift PC design program.

  18. Left ventricular assist devices-current state and perspectives.

    PubMed

    Prinzing, Anatol; Herold, Ulf; Berkefeld, Anna; Krane, Markus; Lange, Rüdiger; Voss, Bernhard

    2016-08-01

    Mechanical circulatory support devices have become an important treatment tool for severe acute and chronic heart failure, since heart transplantation cannot meet the demands because of a lack of available donor organs. Since implantation of the first ventricular assist device a constant development of the suitability of these devices has been made. This review will introduce different generations of left ventricular assist devices (LVAD) and elaborate on clinical indications, risk stratification and current literature. PMID:27621895

  19. Automatic measuring of quality criteria for heart valves

    NASA Astrophysics Data System (ADS)

    Condurache, Alexandru Paul; Hahn, Tobias; Hofmann, Ulrich G.; Scharfschwerdt, Michael; Misfeld, Martin; Aach, Til

    2007-03-01

    Patients suffering from a heart valve deficiency are often treated by replacing the valve with an artificial or biological implant. In case of biological implants, the use of porcine heart valves is common. Quality assessment and inspection methods are mandatory to supply the patients (and also medical research) with only the best such xenograft implants thus reducing the number of follow-up surgeries to replace worn-up valves. We describe an approach for automatic in-vitro evaluation of prosthetic heart valves in an artificial circulation system. We show how to measure the orifice area during a heart cycle to obtain an orifice curve. Different quality parameters are then estimated on such curves.

  20. Mechanical energy storage device for hip disarticulation

    NASA Technical Reports Server (NTRS)

    Vallotton, W. C. (Inventor)

    1977-01-01

    An artificial leg including a trunk socket, a thigh section hingedly coupled to the trunk socket, a leg section hingedly coupled to the thigh section and a foot section hingedly coupled to the leg section is outlined. A mechanical energy storage device is operatively associated with the artificial leg for storage and release of energy during the normal walking stride of the user. Energy is stored in the mechanical energy storage device during a weight-bearing phase of the walking stride when the user's weight is on the artificial leg. Energy is released during a phase of the normal walking stride, when the user's weight is removed from the artificial leg. The stored energy is released from the energy storage device to pivot the thigh section forwardly about the hinged coupling to the trunk socket.