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Sample records for cardiac pacemaker program

  1. Radioisotope-powered cardiac pacemaker program. Clinical studies of the nuclear pacemaker model NU-5. Final report

    SciTech Connect

    Not Available

    1980-06-01

    Beginning in February, 1970, the Nuclear Materials and Equipment Corporation (NUMEC) undertook a program to design, develop and manufacture a radioisotope powered cardiac pacemaker system. The scope of technical work was specified to be: establish system, component, and process cost reduction goals using the prototype Radioisotope Powered Cardiac Pacemaker (RCP) design and develop production techniques to achieve these cost reduction objectives; fabricate radioisotope powered fueled prototype cardiac pacemakers (RCP's) on a pilot production basis; conduct liaison with a Government-designated fueling facility for purposes of defining fueling requirements, fabrication and encapsulation procedures, safety design criteria and quality control and inspection requirements; develop and implement Quality Assurance and Reliability Programs; conduct performance, acceptance, lifetime and reliability tests of fueled RCP's in the laboratory; conduct liaison with the National Institutes of Health and with Government specified medical research institutions selected for the purpose of undertaking clinical evaluation of the RCP in humans; monitor and evaluate, on a continuing basis, all test data; and perform necessary safety analyses and tests. Pacemaker designs were developed and quality assurance and manufacturing procedures established. Prototype pacemakers were fabricated. A total of 126 radioisotope powered units were implanted and have been followed clinically for approximately seven years. Four (4) of these units have failed. Eighty-three (83) units remain implanted and satisfactorily operational. An overall failure rate of less than the target 0.15% per month has been achieved.

  2. [Future cardiac pacemakers technical visions].

    PubMed

    Haeberlin, Andreas; Zurbuchen, Adrian; Pfenniger, Alos; Fuhrer, Jrg; Vogel, Rolf

    2015-08-01

    Cardiac pacemakers are routinely used for the treatment of bradyarrhythmias. Contemporary pacemakers are reliable and allow for a patient specific programming. However, pacemaker replacements due to battery depletion are common (~25 % of all implantation procedures) and bear the risk of complications. Batteryless pacemakers may allow overcoming this limitation. To power a batteryless pacemaker, a mechanism for intracorporeal energy harvesting is required. Such a generator may consist out of subcutaneously implanted solar cells, transforming the small amount of transcutaneously available light into electrical energy. Alternatively, intravascular turbines may harvest energy from the blood flow. Energy may also be harvested from the ventricular wall motion by a dedicated mechanical clockwork converting motion into electrical energy. All these approaches have successfully been tested in vivo. Pacemaker leads constitute another Achilles heel of contemporary pacemakers. Thus, leadless devices are desired. Miniaturized pacemaker circuits and suitable energy harvesting mechanisms (incorporated in a single device) may allow catheter-based implantation of the pacemaker in the heart. Such miniaturized battery- and leadless pacemakers would combine the advantages of both approaches and overcome major limitations of todays systems. PMID:26227982

  3. Trends in cardiac pacemaker batteries.

    PubMed

    Mallela, Venkateswara Sarma; Ilankumaran, V; Rao, N Srinivasa

    2004-01-01

    Batteries used in Implantable cardiac pacemakers-present unique challenges to their developers and manufacturers in terms of high levels of safety and reliability. In addition, the batteries must have longevity to avoid frequent replacements. Technological advances in leads/electrodes have reduced energy requirements by two orders of magnitude. Micro-electronics advances sharply reduce internal current drain concurrently decreasing size and increasing functionality, reliability, and longevity. It is reported that about 600,000 pacemakers are implanted each year worldwide and the total number of people with various types of implanted pacemaker has already crossed 3 million. A cardiac pacemaker uses half of its battery power for cardiac stimulation and the other half for housekeeping tasks such as monitoring and data logging. The first implanted cardiac pacemaker used nickel-cadmium rechargeable battery, later on zinc-mercury battery was developed and used which lasted for over 2 years. Lithium iodine battery invented and used by Wilson Greatbatch and his team in 1972 made the real impact to implantable cardiac pacemakers. This battery lasts for about 10 years and even today is the power source for many manufacturers of cardiac pacemakers. This paper briefly reviews various developments of battery technologies since the inception of cardiac pacemaker and presents the alternative to lithium iodine battery for the near future. PMID:16943934

  4. Trends in Cardiac Pacemaker Batteries

    PubMed Central

    Mallela, Venkateswara Sarma; Ilankumaran, V; Rao, N.Srinivasa

    2004-01-01

    Batteries used in Implantable cardiac pacemakers-present unique challenges to their developers and manufacturers in terms of high levels of safety and reliability. In addition, the batteries must have longevity to avoid frequent replacements. Technological advances in leads/electrodes have reduced energy requirements by two orders of magnitude. Micro-electronics advances sharply reduce internal current drain concurrently decreasing size and increasing functionality, reliability, and longevity. It is reported that about 600,000 pacemakers are implanted each year worldwide and the total number of people with various types of implanted pacemaker has already crossed 3 million. A cardiac pacemaker uses half of its battery power for cardiac stimulation and the other half for housekeeping tasks such as monitoring and data logging. The first implanted cardiac pacemaker used nickel-cadmium rechargeable battery, later on zinc-mercury battery was developed and used which lasted for over 2 years. Lithium iodine battery invented and used by Wilson Greatbatch and his team in 1972 made the real impact to implantable cardiac pacemakers. This battery lasts for about 10 years and even today is the power source for many manufacturers of cardiac pacemakers. This paper briefly reviews various developments of battery technologies since the inception of cardiac pacemaker and presents the alternative to lithium iodine battery for the near future. PMID:16943934

  5. Leadless Cardiac Pacemakers: Back to the Future.

    PubMed

    Miller, Marc A; Neuzil, Petr; Dukkipati, Srinivas R; Reddy, Vivek Y

    2015-09-01

    Despite significant advances in battery longevity, lead performance, and programming features since the first implanted permanent pacemaker was developed, the basic design of cardiac pacemakers has remained relatively unchanged over the past 50 years. Because of inherent limitations in their design, conventional (transvenous) pacemakers are prone to multiple potential short- and long-term complications. Accordingly, there has been intense interest in a system able to provide the symptomatic and potentially lifesaving therapies of cardiac pacemakers while mitigating many of the risks associated with their weakest link-the transvenous lead. Leadless cardiac pacing represents the future of cardiac pacing systems, similar to the transition that occurred from the use of epicardial pacing systems to the familiar transvenous systems of today. This review summarizes the current evidence and potential benefits of leadless pacing systems, which are either commercially available (in Europe) or under clinical investigation. PMID:26337997

  6. Space Derived Health Aids (Cardiac Pacemaker)

    NASA Technical Reports Server (NTRS)

    1981-01-01

    St. Jude Medical's Cardiac Rhythm Management Division's (formerly known as Pacesetter Systems, Inc.) pacer is a rechargeable cardiac pacemaker that eliminates the recurring need for surgery to implant a new battery. The Programalith is an advanced cardiac pacing system which permits a physician to reprogram a patient's implanted pacemaker without surgery. System consists of a pacemaker, together with a physician's console containing the programmer and a data printer. Signals are transmitted by wireless telemetry. Two-way communications, originating from spacecraft electrical power systems technology, allows physician to interrogate the pacemaker as to the status of the heart, then to fine tune the device to best suit the patient's needs.

  7. Psychosocial responses of children to cardiac pacemakers.

    PubMed

    Alpern, D; Uzark, K; Dick, M

    1989-03-01

    To examine the psychosocial responses of children and adolescents with a cardiac pacemaker and compare their responses to those of their peers, we evaluated 30 pediatric pacemaker patients, aged 7 to 19 years, and two age- and sex-matched comparison groups, including 30 patients with similar heart disease but without pacemakers and 30 physically healthy children, using standardized psychometric tests and a specific interview format. We postulated that children with pacemakers would experience greater stress in psychosocial adaptation. No significant differences on standardized measures of trait anxiety, self-competence, or self-esteem were found between the pacemaker group and the comparison groups. In contrast, pacemaker subjects were significantly (p less than 0.05) more external in their locus-of-control orientation than were healthy subjects, suggesting a diminished sense of personal control and less autonomy. Pacemaker subjects, particularly the older ones, had significantly (p less than 0.05) greater knowledge of pacemaker systems than did subjects in the other two groups, facilitating the use of intellectualization as a coping mechanism. The pacemaker patients were likely to be as fearful of social rejection as of potential pacemaker failure. All three groups identified potential negative peer reactions toward an individual with a pacemaker. The patients with cardiac disease but without pacemakers and the healthy subjects perceived significant (p less than 0.05) social and emotional differences between patients with pacemakers and their peers, but the pacemaker patients did not view themselves as different from their peers. This study demonstrates healthy psychosocial adaptation of children with cardiac pacemakers. Although these children appear to cope effectively with the stress of their life situation through the use of denial and intellectualization, they may experience problems both in the development of autonomy and in social isolation and rejection. PMID:2921698

  8. Lithium iodide cardiac pacemakers: initial clinical experience.

    PubMed Central

    Burr, L. H.

    1976-01-01

    A new long-life cardiac pacemaker pulse generator powered by a lithium iodide fuel cell was introduced in Canada in 1973. The compact, hermetically sealed unit is easily implanted and reliable, has excellent patient acceptance and has an anticipated battery life of almost 14 years. Among 105 patients who received a lithium iodide pacemaker, complications occurred in 18. The lithium iodide pacemaker represents a significant advance in pacemaker generator technology and is recommended for long-term cardiac pacing; the manufacturer guarantees the pulse generator for 6 years. Images FIG. 1 PMID:974965

  9. The influence of elevated 50 Hz electric and magnetic fields on implanted cardiac pacemakers: the role of the lead configuration and programming of the sensitivity.

    PubMed

    Toivonen, L; Valjus, J; Hongisto, M; Metso, R

    1991-12-01

    The influence of the electromagnetic interference (EMI) on performance of 15 implanted cardiac pacemakers (12 generator models) was tested during exposure at a high voltage substation. All patients had an adequate spontaneous heart rate during the study. Tests were performed in the ventricular inhibited mode with unipolar sensing in all pacemakers and repeated with bipolar sensing in four pacemakers. The sensitivity was set to a regular, functionally proper level and then to the highest available level. Exposure was done to moderate (1.2-1.7 kV/m) and strong (7.0-8.0 kV/m) electric fields, which correspond to the immediate vicinity of 110 and 400 kV power lines, respectively. In moderate electric fields the output was inhibited in one pacemaker at regular sensitivity (1.7-3.0 mV) and in five pacemakers at the highest sensitivity (0.5-1.25 mV). In strong electric fields the output was inhibited in five pacemakers at regular sensitivity and several pacemakers converted to noise reversion mode at the highest sensitivity. In bipolar mode only one of four pacemakers at high sensitivity (0.5-1.0 mV) was inhibited in the strongest electric field, whereas all four did so in the unipolar mode. One pacemaker with unipolar sensitivity at 0.5 mV was interfered by 63 microT magnetic field. The results confirm that the programmed sensitivity level and the lead configuration markedly influence pacemakers' vulnerability to EMI. Bipolar sensing mode is rather safe in the presence of EMI, which is encountered in public environments. The programmable features of today's pacemakers permit individualized, less stringent safety measures to avoid electromagnetic hazards. PMID:1723194

  10. Mathematical Models of Cardiac Pacemaking Function

    NASA Astrophysics Data System (ADS)

    Li, Pan; Lines, Glenn T.; Maleckar, Mary M.; Tveito, Aslak

    2013-10-01

    Over the past half century, there has been intense and fruitful interaction between experimental and computational investigations of cardiac function. This interaction has, for example, led to deep understanding of cardiac excitation-contraction coupling; how it works, as well as how it fails. However, many lines of inquiry remain unresolved, among them the initiation of each heartbeat. The sinoatrial node, a cluster of specialized pacemaking cells in the right atrium of the heart, spontaneously generates an electro-chemical wave that spreads through the atria and through the cardiac conduction system to the ventricles, initiating the contraction of cardiac muscle essential for pumping blood to the body. Despite the fundamental importance of this primary pacemaker, this process is still not fully understood, and ionic mechanisms underlying cardiac pacemaking function are currently under heated debate. Several mathematical models of sinoatrial node cell membrane electrophysiology have been constructed as based on different experimental data sets and hypotheses. As could be expected, these differing models offer diverse predictions about cardiac pacemaking activities. This paper aims to present the current state of debate over the origins of the pacemaking function of the sinoatrial node. Here, we will specifically review the state-of-the-art of cardiac pacemaker modeling, with a special emphasis on current discrepancies, limitations, and future challenges.

  11. Leadless Cardiac Pacemakers: Pacing Paradigm Change.

    PubMed

    Neuzil, Petr; Reddy, Vivek Y

    2015-08-01

    Traditional transvenous approach for permanent cardiac pacing can be associated with significant acute and chronic complications related partly to either the insertion of transvenous lead or subcutaneous placement of pacemaker device. We summarize the current status of a novel self-contained leadless cardiac pacemaker in the first-in-human and subsequent series of feasibility studies in patients indicated for ventricular rate-responsive pacing (VVI). Using a femoral venous approach, the device is implanted at the right ventricular apical septum region. We describe the technical and clinical characterization of this innovative technology. Two different systems of leadless pacemakers are currently implanted to the patients. Up to now, the electrical parameters, such as pacing thresholds, sensing parameters, and pacing impedances, either improved or remained stable within the accepted range. In this chapter, we also discuss the potential benefit for the future, but in summary, all available data demonstrate the feasibility of leadless cardiac pacing. PMID:26233700

  12. Pacemaker interactions induce reentrant wave dynamics in engineered cardiac culture

    NASA Astrophysics Data System (ADS)

    Borek, Bartłomiej; Shajahan, T. K.; Gabriels, James; Hodge, Alex; Glass, Leon; Shrier, Alvin

    2012-09-01

    Pacemaker interactions can lead to complex wave dynamics seen in certain types of cardiac arrhythmias. We use experimental and mathematical models of pacemakers in heterogeneous excitable media to investigate how pacemaker interactions can be a mechanism for wave break and reentrant wave dynamics. Embryonic chick ventricular cells are cultured invitro so as to create a dominant central pacemaker site that entrains other pacemakers in the medium. Exposure of those cultures to a potassium channel blocker, E-4031, leads to emergence of peripheral pacemakers that compete with each other and with the central pacemaker. Waves emitted by faster pacemakers break up over the slower pacemaker to form reentrant waves. Similar dynamics are observed in a modified FitzHugh-Nagumo model of heterogeneous excitable media with two distinct sites of pacemaking. These findings elucidate a mechanism of pacemaker-induced reentry in excitable media.

  13. The effect of radar on cardiac pacemakers.

    PubMed

    Rohl, D; Laun, H M; Hauber, M E; Stauch, M; Voigt, H

    1975-01-01

    The susceptibility of 16 noncompetitive cardiac pacemakers to radiation from a powerful radar system was investigated in the laboratory and in the vicinity of its prototype. From comparative in vitro tests in air, fat, water, and saline it was concluded that only tests in fat or air represent the worst case condition after implantation. In air all pacemakers showed signs of interference at pulse power densities between 0.025 mW/cm2 and 62.5 mW/CM2. Three of six implanted pacemakers were triggered or inhibited depending on their mode of operation when tested at a location 1.2 km away from the radar station by the radar beam occurring every 5.5 sec. Because interfering radiation can enter the pacemaker circuitry directly along the electrode, acting as an antenna, metal encapsulation of the pulse generator does not provide sufficient shielding against microwave radiation. However, pacemakers modified by metal encapsulation and a low-pass filter at the electrode remained undistrubed at pulse power densities of greater than 10 W/cm2 when tested under worst case condition in air. PMID:1176271

  14. A new multiprogrammable isotopic powered cardiac pacemaker

    SciTech Connect

    Smyth, N.P.; Purdy, D.L.; Sager, D.; Keshishian, J.M.

    1982-09-01

    A new multiprogrammable, isotopic-powered cardiac pacemaker was implanted in six patients as a custom device. Five were initial implants and one was a replacement. The patients were studied for up to two years. In five of the six cases it was found advantageous to change one of the programmable parameters. Multiprogrammability is obviously as important in an isotopic pulse generator as in a lithium unit, if not more so, because of the unit's greater longevity. Further studies are continuing in an FDA approved clinical trial.

  15. Testing of Common Electromagnetic Environments for Risk of Interference with Cardiac Pacemaker Function

    PubMed Central

    Tiikkaja, Maria; Aro, Aapo L.; Alanko, Tommi; Lindholm, Harri; Sistonen, Heli; Hartikainen, Juha E.K.; Toivonen, Lauri; Juutilainen, Jukka; Hietanen, Maila

    2013-01-01

    Background Cardiac pacemakers are known to be susceptible to strong electromagnetic fields (EMFs). This in vivo study investigated occurrence of electromagnetic interference with pacemakers caused by common environmental sources of EMFs. Methods Eleven volunteers with a pacemaker were exposed to EMFs produced by two mobile phone base stations, an electrically powered commuter train, and an overhead high voltage transmission lines. All the pacemakers were programmed in normal clinically selected settings with bipolar sensing and pacing configurations. Results None of the pacemakers experienced interference in any of these exposure situations. However, often it is not clear whether or not strong EMFs exist in various work environments, and hence an individual risk assessment is needed. Conclusions Modern pacemakers are well shielded against external EMFs, and workers with a pacemaker can most often return to their previous work after having a pacemaker implanted. However, an appropriate risk assessment is still necessary after the implantation of a pacemaker, a change of its generator, or major modification of its programming settings. PMID:24106646

  16. Modern Perspectives on Numerical Modeling of Cardiac Pacemaker Cell

    PubMed Central

    Maltsev, Victor A.; Yaniv, Yael; Maltsev, Anna V.; Stern, Michael D.; Lakatta, Edward G.

    2015-01-01

    Cardiac pacemaking is a complex phenomenon that is still not completely understood. Together with experimental studies, numerical modeling has been traditionally used to acquire mechanistic insights in this research area. This review summarizes the present state of numerical modeling of the cardiac pacemaker, including approaches to resolve present paradoxes and controversies. Specifically we discuss the requirement for realistic modeling to consider symmetrical importance of both intracellular and cell membrane processes (within a recent “coupled-clock” theory). Promising future developments of the complex pacemaker system models include the introduction of local calcium control, mitochondria function, and biochemical regulation of protein phosphorylation and cAMP production. Modern numerical and theoretical methods such as multi-parameter sensitivity analyses within extended populations of models and bifurcation analyses are also important for the definition of the most realistic parameters that describe a robust, yet simultaneously flexible operation of the coupled-clock pacemaker cell system. The systems approach to exploring cardiac pacemaker function will guide development of new therapies, such as biological pacemakers for treating insufficient cardiac pacemaker function that becomes especially prevalent with advancing age. PMID:24748434

  17. Proton Beam Therapy Interference With Implanted Cardiac Pacemakers

    SciTech Connect

    Oshiro, Yoshiko Sugahara, Shinji; Noma, Mio; Sato, Masato; Sakakibara, Yuzuru; Sakae, Takeji; Hayashi, Yasutaka; Nakayama, Hidetsugu; Tsuboi, Koji; Fukumitsu, Nobuyoshi; Kanemoto, Ayae; Hashimoto, Takayuki; Tokuuye, Koichi

    2008-11-01

    Purpose: To investigate the effect of proton beam therapy (PBT) on implanted cardiac pacemaker function. Methods and Materials: After a phantom study confirmed the safety of PBT in patients with cardiac pacemakers, we treated 8 patients with implanted pacemakers using PBT to a total tumor dose of 33-77 gray equivalents (GyE) in dose fractions of 2.2-6.6 GyE. The combined total number of PBT sessions was 127. Although all pulse generators remained outside the treatment field, 4 patients had pacing leads in the radiation field. All patients were monitored by means of electrocardiogram during treatment, and pacemakers were routinely examined before and after PBT. Results: The phantom study showed no effect of neutron scatter on pacemaker generators. In the study, changes in heart rate occurred three times (2.4%) in 2 patients. However, these patients remained completely asymptomatic throughout the PBT course. Conclusions: PBT can result in pacemaker malfunctions that manifest as changes in pulse rate and pulse patterns. Therefore, patients with cardiac pacemakers should be monitored by means of electrocardiogram during PBT.

  18. Leadless pacemakers: A new era in cardiac pacing.

    PubMed

    Seriwala, Haseeb Munaf; Khan, Muhammad Shahzeb; Munir, Muhammad Bilal; Riaz, Irbaz Bin; Riaz, Haris; Saba, Samir; Voigt, Andrew H

    2016-01-01

    Cardiac pacemakers are a critical management option for patients with rhythm disorders. Current efforts to develop leadless pacemakers have two primary goals: to reduce lead-associated post-procedural morbidity and to avoid the surgical scar associated with placement. After extensive studies on animal models and technological advancements, these devices are currently under investigation for human use. Herein, we review the evidence from animal studies and the technological advancements that have ushered in the era of use in humans. We also discuss different leadless pacemakers currently under investigation, along with limitations and future developments of this innovative concept. PMID:26458791

  19. Purchase and design preferences for cardiac pacemakers.

    PubMed

    Shrivastav, M

    2001-11-01

    This analysis of the criteria for selecting pacemakers highlights the design features that medical practitioners and patients believe are important in the devices they use and their reasons for brand selection. PMID:12938539

  20. Effect of electric and magnetic fields near an HVDC converter terminal on implanted cardiac pacemakers. Final report

    SciTech Connect

    Frazier, M.J.

    1980-08-01

    The electromagnetic fields associated with HVDC converters and transmission lines constitute a unique environment for persons with implanted cardiac pacemakers. A measurement program has been conducted to assess the potential interfering effects of these harmonically rich fields on implanted pacemakers. The experimental procedures that were employed take into account the combined effects of the electric and magnetic fields. The effect of the resulting body current on the response of six pacemakers was assessed in the laboratory, using a previously developed model to relate body current to pacemaker pickup voltage. The results show that R-wave pacemaker reversion can be expected at some locations within the converter facility, but that a large safety margin for unperturbed pacemaker operation exists beneath the transmission lines.

  1. Modeling cardiac pacemakers with relaxation oscillators

    NASA Astrophysics Data System (ADS)

    Grudzi?ski, Krzysztof; ?ebrowski, Jan J.

    2004-05-01

    A modified van der Pol oscillator model was designed in order to reproduce the time series of the action potential generated by a natural pacemaker of the heart (i.e., the SA or the AV node). The main motivation was that the models published up to now were not altogether adequate for research on the heart. Based on either the classical van der Pol oscillator or other nonlinear oscillators, these models were interesting rather because of the physical phenomena that could be obtained (chaos and synchronization). However, they were unable to simulate many important physiological features of true physiological action potentials. We based our research on the experience of other groups which modeled neuronal oscillators. There complex nonlinear oscillators were used whose most important feature was a certain topology of the phase space. In our case, we modified the phase space of the classical van der Pol oscillator by adding two fixed points: a saddle and a node. In addition, a damping term asymmetric with respect to the voltage was introduced. Introduction of these new features into the van der Pol oscillator allowed to change the firing frequency of the pacemaker node without changing the length of the refractory period - an important physiological detail. We also show different ways of changing the pacemaker rhythm. A comparison of the properties of the signal obtained from our model with the features of the action potentials measured by other groups is made.

  2. Materials aspects of implantable cardiac pacemaker leads.

    PubMed

    Bruck, S D; Mueller, E P

    1988-01-01

    The reliability of the leads of the entire pacemaker system is vital as the risks of failure include: (1) loss of pacing due to the deterioration of the polymeric insulator in the physiological environment; (2) thromboembolism due to inadequate blood compatibility of the insulator; (3) tissue reactions at the electrode/tissue interface; (4) general foreign body rejection phenomena; (5) perforation of the leads; and (6) excessive stress applied by sutures causing abrasion and stress cracking. Although silicone has been used widely, some years ago Pellethane (a segmented polyetherurethane-urea) has been introduced as an alternate lead insulator, chiefly because it can be extruded using additives into smooth and thin tubes. The additives (antioxidants), extrusion aids, and low molecular weight polymer chains (oligomers) together represent up to approximately 8% by weight of leachables, depending on the extraction medium. The in vivo degradation of Pellethane is biologic in nature and is most likely associated with the absorption and premeation of body fluids from the surrounding physiologic environment leading to stress cracking via the formation of microvoids. Thermally and biologically unstable biuret and allophonate groups in this polyurethane, exposure of the polymer to high extrusion temperatures, and stresses created within the polymer also play key roles in the degradation process. In the case of electrodes, some corrosion can occur even with noble metals and ions formed with the involvement of penetrating body fluids which may combine with the urethane and/or urea groups of the polyurethane, leading to its further degradation in vivo. The totality of the situation indicates a need for the development of a standard guideline for the uniform and consistent pre-clinical testing and evaluation of new materials and fabrication processes of implantable pacemaker leads. Such guidelines should take into consideration, among others, the physiological environment, species-differences between test animals and humans, and observe reliable statistical interpretations based on sufficient data. PMID:3285160

  3. [MRI compatible cardiac pacemakers and implantable cardioverter defibrillators].

    PubMed

    norek, Michal; Bulava, Alan

    2014-02-01

    Implanted cardiac pacemaker (PM) or implantable cardioverter defibrillator (ICD) has been so far considered a contra-indication to magnetic resonance imaging (MRI). In the last few years MRI conditional cardiac implantable electronic devices have been marketed enabling patients undergo MRI under specific conditions. We present current state of the art and provide overview of available MRI conditional devices. Magnetic resonance imaging in these patients should be performed only in cases where the requested information can not be obtained using alternative imaging technique. PMID:24754416

  4. Pacemaker Dependency after Cardiac Surgery: A Systematic Review of Current Evidence

    PubMed Central

    2015-01-01

    Background Severe postoperative conduction disturbances requiring permanent pacemaker implantation frequently occur following cardiac surgery. Little is known about the long-term pacing requirements and risk factors for pacemaker dependency in this population. Methods We performed a systematic review of the literature addressing rates and predictors of pacemaker dependency in patients requiring permanent pacemaker implantation after cardiac surgery. Using a comprehensive search of the Medline, Web of Science and EMBASE databases, studies were selected for review based on predetermined inclusion and exclusion criteria. Results A total of 8 studies addressing the endpoint of pacemaker-dependency were identified, while 3 studies were found that addressed the recovery of atrioventricular (AV) conduction endpoint. There were 10 unique studies with a total of 780 patients. Mean follow-up ranged from 6–72 months. Pacemaker dependency rates ranged from 32%-91% and recovery of AV conduction ranged from 16%-42%. There was significant heterogeneity with respect to the definition of pacemaker dependency. Several patient and procedure-specific variables were found to be independently associated with pacemaker dependency, but these were not consistent between studies. Conclusions Pacemaker dependency following cardiac surgery occurs with variable frequency. While individual studies have identified various perioperative risk factors for pacemaker dependency and non-resolution of AV conduction disease, results have been inconsistent. Well-conducted studies using a uniform definition of pacemaker dependency might identify patients who will benefit most from early permanent pacemaker implantation after cardiac surgery. PMID:26470027

  5. Functional autonomic innervation of mammalian cardiac pacemaker during the perinatal period.

    PubMed

    Vlk, J; Vincenzi, F F

    1977-01-01

    Sinoatrial node pacemaker tissues from perinatal and adult rabbits, guinea pigs and rats were examined in vitro. Changes in spontaneous pacemaker rate produced by stimulation of intranodal vagal and sympathetic nerve endings, were taken as a measure of functional postganglionic innervation of the pacemaker. Results show marked species differences in the development of functional innervation of the cardiac pacemaker in the perinatal period. PMID:843549

  6. Potential effects of intrinsic heart pacemaker cell mechanisms on dysrhythmic cardiac action potential firing

    PubMed Central

    Yaniv, Yael; Tsutsui, Kenta; Lakatta, Edward G.

    2015-01-01

    The heart's regular electrical activity is initiated by specialized cardiac pacemaker cells residing in the sinoatrial node. The rate and rhythm of spontaneous action potential firing of sinoatrial node cells are regulated by stochastic mechanisms that determine the level of coupling of chemical to electrical clocks within cardiac pacemaker cells. This coupled-clock system is modulated by autonomic signaling from the brain via neurotransmitter release from the vagus and sympathetic nerves. Abnormalities in brain-heart clock connections or in any molecular clock activity within pacemaker cells lead to abnormalities in the beating rate and rhythm of the pacemaker tissue that initiates the cardiac impulse. Dysfunction of pacemaker tissue can lead to tachy-brady heart rate alternation or exit block that leads to long atrial pauses and increases susceptibility to other cardiac arrhythmia. Here we review evidence for the idea that disturbances in the intrinsic components of pacemaker cells may be implemented in arrhythmia induction in the heart. PMID:25755643

  7. Abnormal frequency locking and the function of the cardiac pacemaker

    NASA Astrophysics Data System (ADS)

    Gutman, M.; Aviram, I.; Rabinovitch, A.

    2004-09-01

    A heterogeneous reaction-diffusion medium consisting of two adjoining uniform regions is analyzed. The first region is a purely oscillatory one, while the second is bistable (oscillatory/excitable). We show that such a construction allows an abnormal domination of the low natural frequency of the oscillatory regime over the whole medium (abnormal frequency locking). Bifurcations leading to the appearance of the bistable regime are discussed as well as the specific dynamics of the bistable oscillations. The abnormal frequency-locking phenomenon could explain some dynamical properties of the cardiac pacemaker.

  8. The effects of nuclear magnetic resonance on patients with cardiac pacemakers

    SciTech Connect

    Pavlicek, W.; Geisinger, M.; Castle, L.; Borkowski, G.P.; Meaney, T.F.; Bream, B.L.; Gallagher, J.H.

    1983-04-01

    The effect of nuclear magnetic resonance (NMR) imaging on six representative cardiac pacemakers was studied. The results indicate that the threshold for initiating the asynchronous mode of a pacemaker is 17 gauss. Radiofrequency levels are present in an NMR unit and may confuse or possibly inhibit demand pacemakers, although sensing circuitry is normally provided with electromagnetic interference discrimination. Time-varying magnetic fields can generate pulse amplitudes and frequencies to mimic cardiac activity. A serious limitation in the possibility of imaging a patient with a pacemaker would be the alteration of normal pulsing parameters due to time-varying magnetic fields.

  9. Interference of implanted cardiac pacemakers with TASER X26 dart mode application.

    PubMed

    Leitgeb, Norbert; Niedermayr, Florian; Neubauer, Robert

    2012-06-01

    The prevalence of pacemaker patients among the general population and of conducted energy devices for law enforcement and self-defence is increasing. Consequently, the question on whether cardiac pacemaker patients are at particular risk becomes increasingly important, in particular, as the widespread use of such devices is planned in Europe. The risk of pacemaker patients has been investigated by numerical simulation at detailed anatomical models of patients with cardiac pacemakers implanted in left pectoral, right pectoral, and abdominal positions, with the monopolar electrode placed at the ventricular apex. The induced cardiac pacemaker interference voltages have been assessed for distant application of TASER X26 devices with dart electrodes propelled towards a subject. It could be shown that interference voltages are highest in abdominal pacemaker implantation, while they are about 20% lower in left or right pectoral sites. They remain below the immunity threshold level as defined by safety standards of implanted cardiac pacemakers and of implanted cardioverter defibrillators to prevent persisting malfunction or damage. However, induced voltages are high enough to be sensed by the pacemaker and to capture pacemaker function in case of hits at thorax and abdomen, frontal as well as dorsal. PMID:22691428

  10. Hardware-in-the-loop simulation and energy optimization of cardiac pacemakers.

    PubMed

    Barker, Chris; Kwiatkowska, Marta; Mereacre, Alexandru; Paoletti, Nicola; Patane, Andrea

    2015-08-01

    Implantable cardiac pacemakers are medical devices that can monitor and correct abnormal heart rhythms. To provide the necessary safety assurance for pacemaker software, both testing and verification of the code, as well as testing the entire pacemaker hardware in the loop, is necessary. In this paper, we present a hardware testbed that enables detailed hardware-in-the-loop simulation and energy optimisation of pacemaker algorithms with respect to a heart model. Both the heart and the pacemaker models are encoded in Simulink/Stateflow and translated into executable code, with the pacemaker executed directly on the microcontroller. We evaluate the usefulness of the testbed by developing a parameter synthesis algorithm which optimises the timing parameters based on power measurements acquired in real-time. The experiments performed on real measurements successfully demonstrate that the testbed is capable of energy minimisation in real-time and obtains safe pacemaker timing parameters. PMID:26737950

  11. Excitation model of pacemaker cardiomyocytes of cardiac conduction system

    NASA Astrophysics Data System (ADS)

    Grigoriev, M.; Babich, L.

    2015-11-01

    Myocardium includes typical and atypical cardiomyocytes – pacemakers, which form the cardiac conduction system. Excitation from the atrioventricular node in normal conditions is possible only in one direction. Retrograde direction of pulses is impossible. The most important prerequisite for the work of cardiomyocytes is the anatomical integrity of the conduction system. Changes in contractile force of the cardiomyocytes, which appear periodically, are due to two mechanisms of self-regulation – heterometric and homeometric. Graphic course of the excitation pulse propagation along the heart muscle more accurately reveals the understanding of the arrhythmia mechanism. These models have the ability to visualize the essence of excitation dynamics. However, they do not have the proper forecasting function for result estimation. Integrative mathematical model enables further investigation of general laws of the myocardium active behavior, allows for determination of the violation mechanism of electrical and contractile function of cardiomyocytes. Currently, there is no full understanding of the topography of pacemakers and ionic mechanisms. There is a need for the development of direction of mathematical modeling and comparative studies of the electrophysiological arrangement of cells of atrioventricular connection and ventricular conduction system.

  12. Ionic Currents That Generate the Spontaneous Diastolic Depolarization in Individual Cardiac Pacemaker Cells

    NASA Astrophysics Data System (ADS)

    Shibata, E. F.; Giles, W. R.

    1985-11-01

    An enzymatic dispersion procedure has been developed to obtain viable, spontaneously active single myocytes from cardiac pacemaker tissue: the bullfrog (Rana catesbeiana) sinus venosus. Recordings of time- and voltage-dependent Ca2+ and K+ currents have been made by using a single suction-microelectrode technique. The results show that two time- and voltage-dependent currents interact to modulate the slope of the pacemaker potential. These are: (i) the decay of a delayed rectifier K+ current and (ii) the activation of a Ca2+ current. In addition, the data strongly suggest that cardiac pacemaker tissue does not have an inwardly rectifying background K+ current.

  13. [A new program-controlled telemetry technology for pacemakers].

    PubMed

    Wang, Yu; Huang, Xin-ming; Fang, Zu-xinag

    2002-09-01

    This thesis is about a new technology of program-controlled telemetry for pacemakers. The system utilizes digital logic circuit design, and the program-controlled part uses single chip to control for display and debug. PWM and reflectance telemetry may improve the preciseness and correctness of signal transmission, and reduce the power consumption of pacemakers and prolong the lifetime. PMID:16104257

  14. Advanced Pacemaker

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Synchrony, developed by St. Jude Medical's Cardiac Rhythm Management Division (formerly known as Pacesetter Systems, Inc.) is an advanced state-of-the-art implantable pacemaker that closely matches the natural rhythm of the heart. The companion element of the Synchrony Pacemaker System is the Programmer Analyzer APS-II which allows a doctor to reprogram and fine tune the pacemaker to each user's special requirements without surgery. The two-way communications capability that allows the physician to instruct and query the pacemaker is accomplished by bidirectional telemetry. APS-II features 28 pacing functions and thousands of programming combinations to accommodate diverse lifestyles. Microprocessor unit also records and stores pertinent patient data up to a year.

  15. Simple hand-held metal detectors are an effective means of detecting cardiac pacemakers in the deceased prior to cremation.

    PubMed

    Stone, Jason Lyle; Williams, John; Fearn, Lesley

    2010-05-01

    The hazard of undetected cardiac pacemakers exploding in crematoria is well described. This short report describes the use of an affordable hand-held metal detector to detect cardiac pacemakers. Over the course of a year, the metal detector located 100% of cardiac pacemakers in a district general hospital mortuary. A simple model using pigskin and fat is also used to demonstrate the effectiveness in vitro. Commercially purchased hand-held metal detectors should be used in all mortuaries responsible for detection and removal of cardiac pacemakers prior to cremation. PMID:20360143

  16. Possible Influences of Spark Discharges on Cardiac Pacemakers.

    PubMed

    Korpinen, Leena; Kuisti, Harri; Tarao, Hiroo; Virtanen, Vesa; Pääkkönen, Rauno; Dovan, Thanh; Kavet, Robert

    2016-01-01

    Exposure to spark discharges may occur beneath high voltage transmission lines when contact is initiated with a conductive object (such as a motor vehicle) with the spark discharge mediated by the ambient electric field from the line. The objective of this study was to assess whether such exposures could interfere with the normal functioning of implanted cardiac pacemakers (PMs). The experiment consisted of PMs implanted in a human-sized phantom and then exposed to spark discharge through an upper extremity. A circuit was designed that produced spark discharges between two spherical electrodes fed to the phantom's left hand. The circuit was set to deliver a single discharge per half cycle (every 10 ms) about 10 μs in duration with a peak current of 1.2-1.3 A, thus simulating conditions under a 400-kV power line operating at 50 Hz. Of 29 PMs acquired, all were tested in unipolar configuration and 20 in bipolar configuration with exposure consisting of 2 min of continuous exposure (one unit was exposed for 1 min). No interference was observed in bipolar configuration. One unit in unipolar configuration incorrectly identified ventricular extra systoles (more than 400 beats min(-1)) for 2 s. The use of unipolar configuration in new implants is extremely rare, thus further minimizing the risk of interference with the passage of time. Replication of this study and, if safety for human subjects can be assured, future testing of human subjects is also advisable. PMID:26606060

  17. Programmable Pacemaker

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Released in 1995, the Trilogy cardiac pacemaker is the fourth generation of a unit developed in the 1970s by NASA, Johns Hopkins Applied Physics Laboratory and St. Jude Medical's Cardiac Rhythm Management Division (formerly known as Pacesetter Systems, Inc.). The new system incorporates the company's PDx diagnostic and programming software and a powerful microprocessor that allows more functions to be fully automatic and gives more detailed information on the patient's health and the performance of the pacing systems. The pacemaker incorporates bidirectional telemetry used for space communications for noninvasive communication with the implanted pacemaker, smaller implantable pulse generators from space microminiaturization, and longer-life batteries from technology for spacecraft electrical power systems.

  18. Experimental and theoretical investigation of implantable cardiac pacemaker exposed to low frequency magnetic field.

    PubMed

    Babouri, A; Hedjeidj, A; Guendouz, L

    2009-04-01

    This paper presents in vitro investigation of an implantable cardiac pacemaker exposed to low frequency magnetic fields. The method used in this study is based on the interaction by inductive coupling through the loop formed by the pacemaker and its loads and the surrounding medium. This interaction results in an induced electromotive force between the terminals of the pacemaker, which can potentially disturb its operation. The studied frequencies are 50/60 Hz and 10/25 kHz. The experimental tests were carried out on several cardiac pacemakers, single chamber, and dual chamber. The results show a window effect of the detection circuits of cardiac pacemakers for the four studied frequencies. The modelling of the test bed requires studying the effects of the induced currents generated by the application of a magnetic field. Analytical calculations and Numerical simulations were carried out. We modelled the interactions of the magnetic field with a simplified representation of pacemaker embedded in the medium. The comparison of the results in the air and in vitro enabled us to make an equivalent electric model. The results obtained in experimental and theoretical studies allowed us to validate the test bed. The method applied is valid for other medical implants such as cardiac defibrillators, implant hearing aids system...etc. PMID:19125341

  19. Fatal cardiac thromboembolism in a patient with a pacemaker during ureteroscopic lithotripsy for ureter stone: a case report

    PubMed Central

    Chung, Mee Young; Chae, Su Min

    2015-01-01

    Intracardiac thrombosis is an infrequent and fatal complication in patients with an inserted pacemaker. A patient with an inserted pacemaker scheduled for ureter stone removal experienced cardiac arrest and cardiopulmonary resuscitation under general anesthesia. Echocardiography showed multiple intracardiac thrombi. Preoperative diagnostic workup including echocardiography for the detection of pacemaker lead thrombus, and the need for anticoagulation should be considered in patients with an inserted pacemaker and high-risk factors for thrombosis. PMID:25664159

  20. [Magnetic resonance imaging of patients with cardiac pacemakers--a safe mode of operation].

    PubMed

    Kaasalainen, Touko; Pakarinen, Sami; Hnninen, Helena

    2015-01-01

    Owing to potential serious safety risks, magnetic resonance imagings of patients having cardiac pacemakers have long been forbidden. Due to the increased demand, modes of operation have, however, been developed for safe imaging, taking the benefit-risk aspects into account. The mode of operation devised in collaboration between the HUCH Cardiology Outpatient Clinic and the radiology unit of the HUS Medical Imaging and Physiology makes safe magnetic resonance imagings possible without body area restrictions for all kinds of cardiac pacemaker patients. By using the developed mode of operation, imaging of 268 patients with cardiac pacemakers have already been carried out safely by the end of October 2014. We describe the content of the mode of operation and the current status of the investigations, with a brief look into the future. PMID:26237889

  1. Experimental Evaluation of SAR around an Implanted Cardiac Pacemaker Caused by Mobile Radio Terminal

    NASA Astrophysics Data System (ADS)

    Endo, Yuta; Saito, Kazuyuki; Watanabe, Soichi; Takahashi, Masaharu; Ito, Koichi

    Although the effect of electromagnetic interference on an implanted cardiac pacemaker due to a nearby mobile phone has been investigated, there have been few studies on the enhancement of the specific absorption rate (SAR) around an implanted cardiac pacemaker due to a nearby mobile phone. In this study, the SAR distribution around a pacemaker model embedded in a parallelepiped torso phantom when a mobile phone was nearby was numerically calculated and experimentally measured. The results of both investigations showed a characteristic SAR distribution. The system presented can be used to estimate the effects of electromagnetic interference on implanted electric circuits and thus could lead to the development of guidelines for the safe use of mobile radio terminals near people with medical implants.

  2. Prophylactic antibiotics for cardiac pacemaker implantation. A prospective trail.

    PubMed Central

    Muers, M F; Arnold, A G; Sleight, P

    1981-01-01

    A prospective trial was conducted to assess the value of prophylactic antibiotic treatment in preventing postoperative infection of permanent transvenous pacemaker systems. Four hundred and thirty-one patients were randomly allocated to treatment (234) or no-treatment (197) groups. Treated patients received systemic benzylpenicillin and flucloxacillin just before operation and one and six hours afterwards. Nine primary generator pocket infections occurred without evidence of wound dehiscence or skin erosion. Seven infections were in untreated patients and two in treated patients. Antibiotic prophylaxis diminishes the risk of infection after pacemaker implantations. PMID:7317219

  3. Estimation of EMI Impact by Cellular Radio on Implantable Cardiac Pacemakers in Elevator Using EMF Distributions Inside Human Body

    NASA Astrophysics Data System (ADS)

    Kitagawa, Atsushi; Hikage, Takashi; Nojima, Toshio; Simba, Ally Y.; Watanabe, Soichi

    The purpose of this study is to estimate the possible effect of cellular radio on implantable cardiac pacemakers in elevators. We previously investigated pacemaker EMI in elevator by examining the E-field distribution of horizontal plane at the height of expected for implanted pacemakers inside elevators. In this paper, we introduce our method for estimating EMI impact to implantable cardiac pacemakers using EMF distributions inside the region of the human body in which pacemakers are implanted. Simulations of a human phantom in an elevator are performed and histograms are derived from the resulting EMF distributions. The computed results of field strengths are compared with a certain reference level determined from experimentally obtained maximum interference distance of implantable cardiac pacemakers. This enables us to carry out a quantitative evaluation of the EMI impact to pacemakers by cellular radio transmission. This paper uses a numerical phantom model developed based on an European adult male. The simulations evaluate EMI on implantable cardiac pacemakers in three frequency bands. As a result, calculated E-field strengths are sufficiently low to cause the pacemaker to malfunction in the region examined.

  4. Mechanisms underlying the cardiac pacemaker: the role of SK4 calcium-activated potassium channels

    PubMed Central

    Weisbrod, David; Khun, Shiraz Haron; Bueno, Hanna; Peretz, Asher; Attali, Bernard

    2016-01-01

    The proper expression and function of the cardiac pacemaker is a critical feature of heart physiology. The sinoatrial node (SAN) in human right atrium generates an electrical stimulation approximately 70 times per minute, which propagates from a conductive network to the myocardium leading to chamber contractions during the systoles. Although the SAN and other nodal conductive structures were identified more than a century ago, the mechanisms involved in the generation of cardiac automaticity remain highly debated. In this short review, we survey the current data related to the development of the human cardiac conduction system and the various mechanisms that have been proposed to underlie the pacemaker activity. We also present the human embryonic stem cell-derived cardiomyocyte system, which is used as a model for studying the pacemaker. Finally, we describe our latest characterization of the previously unrecognized role of the SK4 Ca2+-activated K+ channel conductance in pacemaker cells. By exquisitely balancing the inward currents during the diastolic depolarization, the SK4 channels appear to play a crucial role in human cardiac automaticity. PMID:26725737

  5. Mechanisms underlying the cardiac pacemaker: the role of SK4 calcium-activated potassium channels.

    PubMed

    Weisbrod, David; Khun, Shiraz Haron; Bueno, Hanna; Peretz, Asher; Attali, Bernard

    2016-01-01

    The proper expression and function of the cardiac pacemaker is a critical feature of heart physiology. The sinoatrial node (SAN) in human right atrium generates an electrical stimulation approximately 70 times per minute, which propagates from a conductive network to the myocardium leading to chamber contractions during the systoles. Although the SAN and other nodal conductive structures were identified more than a century ago, the mechanisms involved in the generation of cardiac automaticity remain highly debated. In this short review, we survey the current data related to the development of the human cardiac conduction system and the various mechanisms that have been proposed to underlie the pacemaker activity. We also present the human embryonic stem cell-derived cardiomyocyte system, which is used as a model for studying the pacemaker. Finally, we describe our latest characterization of the previously unrecognized role of the SK4 Ca(2+)-activated K(+) channel conductance in pacemaker cells. By exquisitely balancing the inward currents during the diastolic depolarization, the SK4 channels appear to play a crucial role in human cardiac automaticity. PMID:26725737

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

    PubMed Central

    Bandorski, Dirk; Hltgen, 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

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

    PubMed

    Bandorski, Dirk; Hltgen, 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

  8. Pulse Wave Velocity and Cardiac Output vs. Heart Rate in Patients with an Implanted Pacemaker Based on Electric Impedance Method Measurement

    NASA Astrophysics Data System (ADS)

    Soukup, Ladislav; Vondra, Vlastimil; Vi?or, Ivo; Jurk, Pavel; Halmek, Josef

    2013-04-01

    The methods and device for estimation of cardiac output and measurement of pulse wave velocity simultaneously is presented here. The beat-to-beat cardiac output as well as pulse wave velocity measurement is based on application of electrical impedance method on the thorax and calf. The results are demonstrated in a study of 24 subjects. The dependence of pulse wave velocity and cardiac output on heart rate during rest in patients with an implanted pacemaker was evaluated. The heart rate was changed by pacemaker programming while neither exercise nor drugs were applied. The most important result is that the pulse wave velocity, cardiac output and blood pressure do not depend significantly on heart rate, while the stroke volume is reciprocal proportionally to the heart rate.

  9. Precise Estimation of Cellular Radio Electromagnetic Field in Elevators and EMI Impact on Implantable Cardiac Pacemakers

    NASA Astrophysics Data System (ADS)

    Harris, Louis-Ray; Hikage, Takashi; Nojima, Toshio

    The purpose of this paper is to investigate the possible impact of cellular phones' signals on implantable cardiac pacemakers in elevators. This is achieved by carrying out precise numerical simulations based on the Finite-Difference-Time-Domain method to examine the electromagnetic fields in elevator models. In order to examine the realistic and complicated situations where humans are present in the elevator, we apply the realistic homogeneous human phantom and cellular radios operating in the frequency bands 800MHz, 1.5GHz and 2GHz. These computed results of field strength inside the elevator are compared with a certain reference level determined from the experimentally obtained maximum interference distance of implantable cardiac pacemakers. This enables us to carry out a quantitative evaluation of the EMI risk to pacemakers by cellular radio transmission. The results show that for the case when up to 5 mobile radio users are present in the elevator model used, there is no likelihood of pacemaker malfunction for the frequency bands 800MHz, 1.5GHz and 2GHz.

  10. Self-powered cardiac pacemaker enabled by flexible single crystalline PMN-PT piezoelectric energy harvester.

    PubMed

    Hwang, Geon-Tae; Park, Hyewon; Lee, Jeong-Ho; Oh, SeKwon; Park, Kwi-Il; Byun, Myunghwan; Park, Hyelim; Ahn, Gun; Jeong, Chang Kyu; No, Kwangsoo; Kwon, HyukSang; Lee, Sang-Goo; Joung, Boyoung; Lee, Keon Jae

    2014-07-23

    A flexible single-crystalline PMN-PT piezoelectric energy harvester is demonstrated to achieve a self-powered artificial cardiac pacemaker. The energy-harvesting device generates a short-circuit current of 0.223 mA and an open-circuit voltage of 8.2 V, which are enough not only to meet the standard for charging commercial batteries but also for stimulating the heart without an external power source. PMID:24740465

  11. The interference threshold of cardiac pacemakers in electric 50 Hz fields.

    PubMed

    Scholten, A; Silny, J

    2001-01-01

    The aim of the study was to determine a 'worst-case' and a 'real-case' interference threshold for implanted cardiac pace-makers (CPM) in electric 50 Hz fields as they appear in high-voltage plants, e.g. beneath high voltage overhead lines. For this purpose the resulting electrical potential distribution within the thorax area of volunteers from an external homogeneous electrical 50 Hz field was measured. Different factors such as different body geometries as well as inspiration and expiration of the lung were considered. Measurements showed that 1 per 1 kV m(-1) unimpaired electrical field strength (RMS) an interference voltage of about 180 microVpp as real-case value an 400 microVpp as worst-case value would occur at the input of a unipolar ventricularly controlled, left pectorally implanted cardiac pacemaker. Therefore, it is possible under worst-case conditions but unlikely under practice-relevant conditions that an implanted cardiac pacemaker is disturbed by present electric 50 Hz fields beneath high voltage overhead lines. PMID:11345094

  12. 21 CFR 870.5550 - External transcutaneous cardiac pacemaker (noninvasive).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... electrodes such as defibrillator paddles. (b) Classification. Class II. The special controls for this device...-21 ‘Cardiac Defibrillator Devices’ ” 2d ed., 1996, and (2) “The maximum pulse amplitude should...

  13. 21 CFR 870.5550 - External transcutaneous cardiac pacemaker (noninvasive).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... electrodes such as defibrillator paddles. (b) Classification. Class II. The special controls for this device...-21 ‘Cardiac Defibrillator Devices’ ” 2d ed., 1996, and (2) “The maximum pulse amplitude should...

  14. 21 CFR 870.5550 - External transcutaneous cardiac pacemaker (noninvasive).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... electrodes such as defibrillator paddles. (b) Classification. Class II. The special controls for this device...-21 ‘Cardiac Defibrillator Devices’ ” 2d ed., 1996, and (2) “The maximum pulse amplitude should...

  15. 21 CFR 870.5550 - External transcutaneous cardiac pacemaker (noninvasive).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... electrodes such as defibrillator paddles. (b) Classification. Class II. The special controls for this device...-21 ‘Cardiac Defibrillator Devices’ ” 2d ed., 1996, and (2) “The maximum pulse amplitude should...

  16. 21 CFR 870.5550 - External transcutaneous cardiac pacemaker (noninvasive).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... electrodes such as defibrillator paddles. (b) Classification. Class II. The special controls for this device...-21 ‘Cardiac Defibrillator Devices’ ” 2d ed., 1996, and (2) “The maximum pulse amplitude should...

  17. Mortality in Patients on Renal Replacement Therapy and Permanent Cardiac Pacemakers

    PubMed Central

    Vanerio, Gabriel; Garca, Cristina; Gonzlez, Carlota; Ferreiro, Alejandro

    2014-01-01

    End stage renal disease is a relatively frequent disease with high mortality due to cardiac causes. Permanent pacemaker (PM) implantation rates are also very common; thus combination of both conditions is not unusual. We hypothesized that patients with chronic kidney disease with a PM would have significantly higher mortality rates compared with end stage renal disease patients without PM. Our objectives were to analyze mortality of patients on renal replacement therapy with PM. 2778 patients were on renal replacement therapy (RRT) and 110 had a PM implanted during the study period. To reduce the confounding effects of covariates, a propensity-matched score was performed. 52 PM patients and 208 non-PM matched patients were compared. 41% of the PM were implanted before entering the RRT program and 59% while on RRT. Mortality was higher in the PM group. Cardiovascular disease and infections were the most frequent causes of death. Propensity analysis showed no differences in long-term mortality between groups. We concluded that in patients on RRT and PM mortality rates are higher. Survival curves did not differ from a RRT propensity-matched group. We concluded that the presence of a PM is not an independent mortality risk factor in RRT patients. PMID:24977040

  18. Effects of electromagnetic pulse (EMP) on cardiac pacemakers. Final report, Nov 88-Oct 89

    SciTech Connect

    Ellis, V.J.

    1991-11-01

    The U.S. Army Harry Diamond Laboratories' (HDL's) Woodbridge Research Facility (WRF) has conducted an investigation into the effects of electromagnetic pulse (EMP) on medical electronics. This report specifically documents the findings on the effects of WRF's Army EMP Simulator Operations (AESOP) on cardiac pacemakers (CPMs). Empirical data are furnished and compared to the results of two independent analytical studies. The studies support the conclusion that damage to CPMs that might be located near the WRF boundaries is not likely. Furthermore, any upset in a CPM's operation is considered unlikely and inconsequential to the health of the CPM wearer. Cardiac pacemakers (CPMs) have experienced significant technological advancements over the last decade, evolving from simple and bulky pulse generators to the small and sophisticated computerized units implanted today. With the implementation of sensitive digital electronics in modern pacemaker designs, concerns have been expressed for the possibility of an increased sensitivity of CPMs to electromagnetic interference (EMI). To some extent these concerns have abated to the increased awareness of the EMI problem by the manufacturers, as evident in better peacemaker designs and the decline in reported malfunctions due to EMI.

  19. Cardiorespiratory Mechanical Simulator for In Vitro Testing of Impedance Minute Ventilation Sensors in Cardiac Pacemakers.

    PubMed

    Marcelli, Emanuela; Cercenelli, Laura

    2016-01-01

    We developed a cardiorespiratory mechanical simulator (CRMS), a system able to reproduce both the cardiac and respiratory movements, intended to be used for in vitro testing of impedance minute ventilation (iMV) sensors in cardiac pacemakers. The simulator consists of two actuators anchored to a human thorax model and a software interface to control the actuators and to acquire/process impedance signals. The actuators can be driven separately or simultaneously to reproduce the cardiac longitudinal shortening at a programmable heart rate and the diaphragm displacement at a programmable respiratory rate (RR). A standard bipolar pacing lead moving with the actuators and a pacemaker case fixed to the thorax model have been used to measure impedance (Z) variations during the simulated cardiorespiratory movements. The software is able to discriminate the low-frequency component because of respiration (ZR) from the high-frequency ripple because of cardiac effect (ZC). Impedance minute ventilation is continuously calculated from ZR and RR. From preliminary tests, the CRMS proved to be a reliable simulator for in vitro evaluation of iMV sensors. Respiration impedance recordings collected during cardiorespiratory movements reproduced by the CRMS were comparable in morphology and amplitude with in vivo assessments of transthoracic impedance variations. PMID:26501915

  20. Programmable Pacemaker

    NASA Technical Reports Server (NTRS)

    1980-01-01

    St. Jude Medical's Cardiac Rhythm Management Division, formerly known as Pacesetter Systems, Inc., incorporated Apollo technology into the development of the programmable pacemaker system. This consists of the implantable pacemaker together with a physician's console containing the programmer and a data printer. Physician can communicate with patient's pacemaker by means of wireless telemetry signals transmitted through the communicating head held over the patient's chest. Where earlier pacemakers deliver a fixed type of stimulus once implanted, Programalith enables surgery free "fine tuning" of device to best suit the patient's changing needs.

  1. Seven times replacement of permanent cardiac pacemaker in 33 years to maintain adequate heart rate: a case report.

    PubMed

    Hao, Yinglu; Li, Yanping; Liao, Derong; Yang, Ling

    2015-12-01

    Over the past few decades, recent developments in pacemaker technology from fixed-rate single-chamber pacemakers to dual chamber pacemakers with pacing algorithms have changed the therapeutic landscape resulting in better healthcare outcomes by improving rate response with minimal ventricular pacing. Here, we share our longest clinical experience with an elderly Chinese male patient who was diagnosed with third-degree atrioventricular (AV) block and was admitted in our hospital 33 years ago. An 85-year-old male patient from China was hospitalized due to dizziness and syncope, with an initial diagnosis revealing third-degree AV block with a heart rate of 35-40 beats per minute (bpm) along with Aase's syndrome and primary hypertension. A single-chamber pacemaker (VVI) was implanted immediately giving the patient symptomatic relief. However, 5-year post-surgery VVI was replaced due to battery exhaustion, while the primary electrode catheter was kept in use. Few years later, the patient again complained of dizziness and re-examination revealed VVI battery debilitation due to premature battery exhaustion. Single-chamber pacemaker was again implanted via the same position of right upper chest. However, after adjusting the frequency of stimulation of the pacemaker to 70 bpm, patient had a symptomatic relief. Considering the severity of patient's disease and knowing that cardiac dysfunction was reported previously, a tri-chamber pacemaker was chosen to take place of previous single-chamber pacemaker. For 33 years, the patient underwent 7 times replacement of pacemaker for battery exhaustion or inadequacy. We successfully performed overall seven pacemaker implantations and upgradation in an elderly Chinese patient diagnosed with third-degree AV block for 33 years. A long following up till now demonstrated no major complications with normal heart rate functioning. PMID:26734649

  2. Seven times replacement of permanent cardiac pacemaker in 33 years to maintain adequate heart rate: a case report

    PubMed Central

    Li, Yanping; Liao, Derong; Yang, Ling

    2015-01-01

    Over the past few decades, recent developments in pacemaker technology from fixed-rate single-chamber pacemakers to dual chamber pacemakers with pacing algorithms have changed the therapeutic landscape resulting in better healthcare outcomes by improving rate response with minimal ventricular pacing. Here, we share our longest clinical experience with an elderly Chinese male patient who was diagnosed with third-degree atrioventricular (AV) block and was admitted in our hospital 33 years ago. An 85-year-old male patient from China was hospitalized due to dizziness and syncope, with an initial diagnosis revealing third-degree AV block with a heart rate of 3540 beats per minute (bpm) along with Aases syndrome and primary hypertension. A single-chamber pacemaker (VVI) was implanted immediately giving the patient symptomatic relief. However, 5-year post-surgery VVI was replaced due to battery exhaustion, while the primary electrode catheter was kept in use. Few years later, the patient again complained of dizziness and re-examination revealed VVI battery debilitation due to premature battery exhaustion. Single-chamber pacemaker was again implanted via the same position of right upper chest. However, after adjusting the frequency of stimulation of the pacemaker to 70 bpm, patient had a symptomatic relief. Considering the severity of patients disease and knowing that cardiac dysfunction was reported previously, a tri-chamber pacemaker was chosen to take place of previous single-chamber pacemaker. For 33 years, the patient underwent 7 times replacement of pacemaker for battery exhaustion or inadequacy. We successfully performed overall seven pacemaker implantations and upgradation in an elderly Chinese patient diagnosed with third-degree AV block for 33 years. A long following up till now demonstrated no major complications with normal heart rate functioning. PMID:26734649

  3. Improved quality of life after treatment of prolonged asystole during breath holding spells with a cardiac pacemaker

    PubMed Central

    Kolterer, Bruno; Gebauer, Roman Antonin; Janousek, Jan; Dhnert, Ingo; Riede, Frank Thomas; Paech, Christian

    2015-01-01

    Objectives: To validate the physical and psychological effectiveness of cardiac pacing in pediatric patients with breath-holding spells (BHS) and prolonged asystole. Materials and Methods: The records and clinical data of all the patients with BHS who presented to our center in the period of 20012013 were reviewed. All patients who received cardiac pacemaker implantation for prolonged asystole during BHS were included. In addition, the parents were asked to fill out a standardized quality of life (QOL) questionnaire. Results: Seven patients were identified. The mean onset of symptoms was 7 month (112 months) of age, documented asystole was 1221 seconds, and a permanent cardiac pacemaker device was implanted at a mean age of 23 months (8 months3.9 years). No pacemaker related adverse events were recorded. Follow up showed immediate resolution from spells in four cases (4/7). Two patients (2/7) showed significant reduction of frequency and severity of spells, with complete elimination of loss of consciousness (LOC). One patient (1/7) with an additional neurologic disorder continued to have minor pallid BHS and eventually switched from pallid to cyanotic spells without further detection of bradycardia or asystole in holter examination. QOL questionnaire revealed significant reduction in subjective stress levels of patients (P = 0.012) and parents (P = 0.007) after pacemaker implantation. Conclusion: Cardiac pacing using appropriate pacemaker settings seems effective in the prevention of LOC and reduction of the frequency of BHS. Our results imply a reduction of subjective stress levels of patients and parents as well as an increased quality of everyday life. After all, randomized controlled trials of the influence of cardiac pacemaker implantation on subjective stress levels in patients with BHS are needed. PMID:26085761

  4. The interference threshold of unipolar cardiac pacemakers in extremely low frequency magnetic fields.

    PubMed

    Scholten, A; Silny, J

    2001-01-01

    The effective induction loop area of implanted cardiac pacemaker (CPM) systems in magnetic fields was determined. The results were verified in a tank model placed in the centre of a Helmholtz-coil-arrangement. Both a left and a right pectorally implanted unipolar dual chamber CPM system were simulated. On this basis and with the results of benchmark-tests the interference thresholds for a collection of modern CPMs in extremely low frequency (ELF) magnetic fields were estimated. The investigations clearly showed that there are two loops, the CPM-lead-tissue-loop and the body loop, responsible for the magnitude of the disturbance voltage on the input of a cardiac pacemaker. The effective induction loop areas rangedfrom 100 to 221 cm2. For a left pectorally implanted, atrially controlled CPM system the interference thresholds for the magnetic induction lay between 16 and 552 micro T (RMS) for frequencies of the magneticfield between 10 and 250 Hz. Thus, there is a limited possibility for an interference of implanted CPM by ELF magnetic fields in everyday life. PMID:11695658

  5. Unipolar cardiac pacemakers in electromagnetic fields of high voltage overhead lines.

    PubMed

    Scholten, A; Joosten, S; Silny, J

    2005-01-01

    Experimental studies have shown that both electric and magnetic extremely low frequency fields are able to disturb a cardiac pacemaker (CPM) at certain field strengths. However, the simultaneous influence of multiphase electric and magnetic fields beneath high voltage overhead lines (HVOLs) has not yet been investigated. Therefore, the distribution of the electric and the magnetic field as well as the phase angle between both components for an exemplary HVOL was numerically calculated. The calculations show that the phase difference of the capacitive and the inductive induced voltage on the input of an implanted cardiac pacemaker is position-dependent. Based on these and our earlier results a worst-case-scenario for two virtual patients beneath an exemplary HVOL was derived. It turned out that although the interference of CPMs by the electromagnetic fields (EMFs) of HVOLs cannot be ruled out, the life-threatening interference condition 'inhibition by EMF' is unlikely. Due to various factors depending on technical parameters and the individual patient a definite answer about the disturbance of an implanted CPM beneath HVOLs can be given by studies with real CPM patients only. PMID:16012068

  6. Mechanisms of beat-to-beat regulation of cardiac pacemaker cell function by Ca? cycling dynamics.

    PubMed

    Yaniv, Yael; Stern, Michael D; Lakatta, Edward G; Maltsev, Victor A

    2013-10-01

    Whether intracellular Ca(2+) cycling dynamics regulate cardiac pacemaker cell function on a beat-to-beat basis remains unknown. Here we show that under physiological conditions, application of low concentrations of caffeine (2-4 mM) to isolated single rabbit sinoatrial node cells acutely reduces their spontaneous action potential cycle length (CL) and increases Ca(2+) transient amplitude for several cycles. Numerical simulations, using a modified Maltsev-Lakatta coupled-clock model, faithfully reproduced these effects, and also the effects of CL prolongation and dysrhythmic spontaneous beating (produced by cytosolic Ca(2+) buffering) and an acute CL reduction (produced by flash-induced Ca(2+) release from a caged Ca(2+) buffer), which we had reported previously. Three contemporary numerical models (including the original Maltsev-Lakatta model) failed to reproduce the experimental results. In our proposed new model, Ca(2+) releases acutely change the CL via activation of the Na(+)/Ca(2+) exchanger current. Time-dependent CL reductions after flash-induced Ca(2+) releases (the memory effect) are linked to changes in Ca(2+) available for pumping into sarcoplasmic reticulum which, in turn, changes the sarcoplasmic reticulum Ca(2+) load, diastolic Ca(2+) releases, and Na(+)/Ca(2+) exchanger current. These results support the idea that Ca(2+) regulates CL in cardiac pacemaker cells on a beat-to-beat basis, and suggest a more realistic numerical mechanism of this regulation. PMID:24094396

  7. Pacemakers and Implantable Defibrillators

    MedlinePLUS

    ... need a cardiac pacemaker or an implantable cardioverter defibrillator (ICD). They are devices that are implanted in ... can act as both a pacemaker and a defibrillator. Many ICDs also record the heart's electrical patterns ...

  8. Genetically engineered cardiac pacemaker: Stem cells transfected with HCN2 gene and myocytesA model

    NASA Astrophysics Data System (ADS)

    Kanani, S.; Pumir, A.; Krinsky, V.

    2008-01-01

    One of the successfully tested methods to design genetically engineered cardiac pacemaker cells consists in transfecting a human mesenchymal stem cell (hMSC) with a HCN2 gene and connecting it to a myocyte. We develop and study a mathematical model, describing a myocyte connected to a hMSC transfected with a HCN2 gene. The cardiac action potential is described both with the simple Beeler Reuter model, as well as with the elaborate dynamic Luo Rudy model. The HCN2 channel is described by fitting electrophysiological records, in the spirit of Hodgkin Huxley. The model shows that oscillations can occur in a pair myocyte-stem cell, that was not observed in the experiments yet. The model predicted that: (1) HCN pacemaker channels can induce oscillations only if the number of expressed I channels is low enough. At too high an expression level of I channels, oscillations cannot be induced, no matter how many pacemaker channels are expressed. (2) At low expression levels of I channels, a large domain of values in the parameter space (n, N) exists, where oscillations should be observed. We denote N the number of expressed pacemaker channels in the stem cell, and n the number of gap junction channels coupling the stem cell and the myocyte. (3) The expression levels of I channels observed in ventricular myocytes, both in the Beeler Reuter and in the dynamic Luo Rudy models are too high to allow to observe oscillations. With expression levels below 1/4 of the original value, oscillations can be observed. The main consequence of this work is that in order to obtain oscillations in an experiment with a myocyte-stem cell pair, increasing the values of n, N is unlikely to be helpful, unless the expression level of I has been reduced enough. The model also allows us to explore levels of gene expression not yet achieved in experiments, and could be useful to plan new experiments, aimed at improving the robustness of the oscillations.

  9. Stochastic vagal modulation of cardiac pacemaking may lead to erroneous identification of cardiac ``chaos''

    NASA Astrophysics Data System (ADS)

    Zhang, J. Q.; Holden, A. V.; Monfredi, O.; Boyett, M. R.; Zhang, H.

    2009-06-01

    Fluctuations in the time interval between two consecutive R-waves of electrocardiogram during normal sinus rhythm may result from irregularities in the autonomic drive of the pacemaking sinoatrial node (SAN). We use a biophysically detailed mathematical model of the action potentials of rabbit SAN to quantify the effects of fluctuations in acetylcholine (ACh) on the pacemaker activity of the SAN and its variability. Fluctuations in ACh concentration model the effect of stochastic activity in the vagal parasympathetic fibers that innervate the SAN and produce varying rates of depolarization during the pacemaker potential, leading to fluctuations in cycle length (CL). Both the estimated maximal Lyapunov exponent and the noise limit of the resultant sequence of fluctuating CLs suggest chaotic dynamics. Apparently chaotic heart rate variability (HRV) seen in sinus rhythm can be produced by stochastic modulation of the SAN. The identification of HRV data as chaotic by use of time series measures such as a positive maximal Lyapunov exponent or positive noise limit requires both caution and a quantitative, predictive mechanistic model that is fully deterministic.

  10. Magnetic resonance imaging in patients with cardiac pacemakers: era of "MR Conditional" designs

    PubMed Central

    2011-01-01

    Advances in cardiac device technology have led to the first generation of magnetic resonance imaging (MRI) conditional devices, providing more diagnostic imaging options for patients with these devices, but also new controversies. Prior studies of pacemakers in patients undergoing MRI procedures have provided groundwork for design improvements. Factors related to magnetic field interactions and transfer of electromagnetic energy led to specific design changes. Ferromagnetic content was minimized. Reed switches were modified. Leads were redesigned to reduce induced currents/heating. Circuitry filters and shielding were implemented to impede or limit the transfer of certain unwanted electromagnetic effects. Prospective multicenter clinical trials to assess the safety and efficacy of the first generation of MR conditional cardiac pacemakers demonstrated no significant alterations in pacing parameters compared to controls. There were no reported complications through the one month visit including no arrhythmias, electrical reset, inhibition of generator output, or adverse sensations. The safe implementation of these new technologies requires an understanding of the well-defined patient and MR system conditions. Although scanning a patient with an MR conditional device following the strictly defined patient and MR system conditions appears straightforward, issues related to patients with pre-existing devices remain complex. Until MR conditional devices are the routine platform for all of these devices, there will still be challenging decisions regarding imaging patients with pre-existing devices where MRI is required to diagnose and manage a potentially life threatening or serious scenario. A range of other devices including ICDs, biventricular devices, and implantable physiologic monitors as well as guidance of medical procedures using MRI technology will require further biomedical device design changes and testing. The development and implementation of cardiac MR conditional devices will continue to require the expertise and collaboration of multiple disciplines and will need to prove safety, effectiveness, and cost effectiveness in patient care. PMID:22032338

  11. Early performance of a miniaturized leadless cardiac pacemaker: the Micra Transcatheter Pacing Study

    PubMed Central

    Ritter, Philippe; Duray, Gabor Z.; Steinwender, Clemens; Soejima, Kyoko; Omar, Razali; Mont, Llus; Boersma, Lucas VA; Knops, Reinoud E.; Chinitz, Larry; Zhang, Shu; Narasimhan, Calambur; Hummel, John; Lloyd, Michael; Simmers, Timothy Alexander; Voigt, Andrew; Laager, Verla; Stromberg, Kurt; Bonner, Matthew D.; Sheldon, Todd J.; Reynolds, Dwight

    2015-01-01

    Aims Permanent cardiac pacing is the only effective treatment for symptomatic bradycardia, but complications associated with conventional transvenous pacing systems are commonly related to the pacing lead and pocket. We describe the early performance of a novel self-contained miniaturized pacemaker. Methods and results Patients having Class I or II indication for VVI pacing underwent implantation of a Micra transcatheter pacing system, from the femoral vein and fixated in the right ventricle using four protractible nitinol tines. Prespecified objectives were >85% freedom from unanticipated serious adverse device events (safety) and <2 V 3-month mean pacing capture threshold at 0.24 ms pulse width (efficacy). Patients were implanted (n = 140) from 23 centres in 11 countries (61% male, age 77.0 10.2 years) for atrioventricular block (66%) or sinus node dysfunction (29%) indications. During mean follow-up of 1.9 1.8 months, the safety endpoint was met with no unanticipated serious adverse device events. Thirty adverse events related to the system or procedure occurred, mostly due to transient dysrhythmias or femoral access complications. One pericardial effusion without tamponade occurred after 18 device deployments. In 60 patients followed to 3 months, mean pacing threshold was 0.51 0.22 V, and no threshold was ?2 V, meeting the efficacy endpoint (P < 0.001). Average R-wave was 16.1 5.2 mV and impedance was 650.7 130 ohms. Conclusion Early assessment shows the transcatheter pacemaker can safely and effectively be applied. Long-term safety and benefit of the pacemaker will further be evaluated in the trial. Clinical Trial Registration ClinicalTrials.gov ID NCT02004873. PMID:26045305

  12. Trends in the incidence and prevalence of cardiac pacemaker insertions in an ageing population

    PubMed Central

    Bradshaw, Pamela J; Stobie, Paul; Knuiman, Matthew W; Briffa, Thomas G; Hobbs, Michael S T

    2014-01-01

    Objectives To determine contemporary population estimates of the prevalence of cardiac permanent pacemaker (PPM) insertions. Methods A population-based observational study using linked hospital morbidity and death registry data from Western Australia (WA) to identify all incident cases of PPM insertion for adults aged 18?years or older. Prevalence rates were calculated by age and sex for the years 19952009 for the WA population. Results There were 9782 PPMs inserted during 19952009. Prevalence rose across the study period, exceeding 1 in 50 among people aged 75 or older from 2005. This was underpinned by incidence rates which rose with age, being highest in those 85?years or older; over 500/100?000 for men throughout, and over 200/100?000 for women. Rates for patients over 75 were more than double the rates for those aged 6574?years. Women were around 40% of cases overall. The use of dual-chamber and triple-chamber pacing increased across the study period. A cardiac resynchronisation defibrillator was implanted for 58% of patients treated with cardiac resynchronisation therapy. Conclusions Rates of insertion and prevalence of PPM continue to rise with the ageing population in WA. As equilibrium has probably not been reached, the demand for pacing services in similarly well-developed economies is likely to continue to grow. PMID:25512875

  13. The relevance of non-excitable cells for cardiac pacemaker function.

    PubMed

    Fahrenbach, John P; Mejia-Alvarez, Rafael; Banach, Kathrin

    2007-12-01

    Age-dependent changes in the architecture of the sinus node comprise an increasing ratio between fibroblasts and cardiomyocytes. This change is discussed as a potential mechanism for sinus node disease. The goal of this study was to determine the mechanism through which non-excitable cells influence the spontaneous activity of multicellular cardiomyocyte preparations. Cardiomyocyte monolayers (HL-1 cells) or embryonic stem cell-derived cardiomyocytes were used as two- and three-dimensional cardiac pacemaker models. Spontaneous activity and conduction velocity (theta) were monitored by field potential measurements with microelectrode arrays (MEAs). The influence of fibroblasts (WT-fibs) was determined in heterocellular cultures of different cardiomyocyte and fibroblast ratios. The relevance of heterocellular gap junctional coupling was evaluated by the use of fibroblasts deficient for the expression of Cx43 (Cx43(-/-)-fibs). The beating frequency and of heterocellular cultures depended negatively on the fibroblast concentration. Interspersion of fibroblasts in cardiomyocyte monolayers increased the coefficient of the interbeat interval variability. Whereas Cx43(-/-)-fibs decreased theta significantly less than WT-fibs, their effect on the beating frequency and the beat-to-beat variability seemed largely independent of their ability to establish intercellular coupling. These results suggest that electrically integrated, non-excitable cells modulate the excitability of cardiac pacemaker preparations by two distinct mechanisms, one dependent and the other independent of the heterocellular coupling established. Whereas heterocellular coupling enables the fibroblast to depolarize the cardiomyocytes or to act as a current sink, the mere physical separation of the cardiomyocytes by fibroblasts induces bradycardia through a reduction in frequency entrainment. PMID:17932143

  14. Mechanistic links between Na+ channel (SCN5A) mutations and impaired cardiac pacemaking in sick sinus syndrome

    PubMed Central

    Butters, Timothy D.; Aslanidi, Oleg V.; Inada, Shin; Boyett, Mark R.; Hancox, Jules C.; Lei, Ming; Zhang, Henggui

    2010-01-01

    RATIONALE Familial sick sinus syndrome (SSS) has been linked to loss-of-function mutations of the SCN5A gene, which result in decreased inward Na+ current, INa. However, the functional role of INa in cardiac pacemaking is controversial, and mechanistic links between the mutations and sinus node dysfunction (SND) in SSS are unclear. OBJECTIVE To determine mechanisms by which the SCN5A mutations impair cardiac pacemaking. METHODS Action potential (AP) models for rabbit sinoatrial node (SAN) cells were modified to incorporate experimentally reported INa changes induced by two groups of SCN5A gene mutations (affecting the activation and inactivation of INa, respectively). The cell models were incorporated into an anatomically detailed 2D model of the intact SAN-atrium. Effects of the mutations and vagal nerve activity on cardiac pacemaking at the single cell and tissue levels were studied. Multi-electrode extracellular potential recordings of activation pattern from intact SAN-atrium preparations were performed to test predictions of the models. RESULTS At the single cell level, the mutations slowed down pacemaking rates in peripheral, but not in central SAN cells that control the heart rhythm. However, in tissue simulations, the mutations not only slowed down pacemaking, but also compromised AP conduction across the SAN-atrium, leading to a possible SAN exit block or sinus arrest, the major features of SSS. Simulated vagal nerve activity amplified the bradycardiac effects of the mutations. Two groups of SCN5A mutations showed subtle differences in impairing the ability of the SAN to drive the surrounding atrium primarily, due to their differential effects on atrial excitability and conduction safety. Experimental data with tetrodotoxin and carbachol confirmed the simulation outcomes. CONCLUSIONS Our study substantiates the causative link between SCN5A gene mutations and SSS, and illustrates mechanisms by which the mutations impair the driving ability of the SAN. PMID:20448214

  15. Pheochromocytoma-induced atrial tachycardia leading to cardiogenic shock and cardiac arrest: resolution with atrioventricular node ablation and pacemaker placement.

    PubMed

    Shawa, Hassan; Bajaj, Mandeep; Cunningham, Glenn R

    2014-12-01

    Pheochromocytoma should be considered in young patients who have acute cardiac decompensation, even if they have no history of hypertension. Atrioventricular node ablation and pacemaker placement should be considered for stabilizing pheochromocytoma patients with cardiogenic shock due to atrial tachyarrhythmias. A 38-year-old black woman presented with cardiogenic shock (left ventricular ejection fraction, <0.15) that did not respond to the placement of an intra-aortic balloon pump. A TandemHeart() Percutaneous Ventricular Assist Device was inserted emergently. After atrioventricular node ablation and placement of a temporary pacemaker, the TandemHeart was removed. Computed tomography of the abdomen revealed a pheochromocytoma. After placement of a permanent pacemaker, the patient underwent a right adrenalectomy. This is, to our knowledge, the first reported case of pheochromocytoma-induced atrial tachyarrhythmia that led to cardiogenic shock and cardiac arrest unresolved by the placement of 2 different ventricular assist devices, but that was completely reversed by radiofrequency ablation of the atrioventricular node and the placement of a temporary pacemaker. We present the patient's clinical, laboratory, and imaging findings, and we review the relevant literature. PMID:25593537

  16. SK4 Ca2+ activated K+ channel is a critical player in cardiac pacemaker derived from human embryonic stem cells

    PubMed Central

    Weisbrod, David; Peretz, Asher; Ziskind, Anna; Menaker, Nataly; Oz, Shimrit; Barad, Lili; Eliyahu, Sivan; Itskovitz-Eldor, Joseph; Dascal, Nathan; Khananshvili, Daniel; Binah, Ofer; Attali, Bernard

    2013-01-01

    Proper expression and function of the cardiac pacemaker is a critical feature of heart physiology. Two main mechanisms have been proposed: (i) the voltage-clock, where the hyperpolarization-activated funny current If causes diastolic depolarization that triggers action potential cycling; and (ii) the Ca2+ clock, where cyclical release of Ca2+ from Ca2+ stores depolarizes the membrane during diastole via activation of the Na+Ca2+ exchanger. Nonetheless, these mechanisms remain controversial. Here, we used human embryonic stem cell-derived cardiomyocytes (hESC-CMs) to study their autonomous beating mechanisms. Combined current- and voltage-clamp recordings from the same cell showed the so-called voltage and Ca2+ clock pacemaker mechanisms to operate in a mutually exclusive fashion in different cell populations, but also to coexist in other cells. Blocking the voltage or Ca2+ clock produced a similar depolarization of the maximal diastolic potential (MDP) that culminated by cessation of action potentials, suggesting that they converge to a common pacemaker component. Using patch-clamp recording, real-time PCR, Western blotting, and immunocytochemistry, we identified a previously unrecognized Ca2+-activated intermediate K+ conductance (IKCa, KCa3.1, or SK4) in young and old stage-derived hESC-CMs. IKCa inhibition produced MDP depolarization and pacemaker suppression. By shaping the MDP driving force and exquisitely balancing inward currents during diastolic depolarization, IKCa appears to play a crucial role in human embryonic cardiac automaticity. PMID:23589888

  17. Discontinuities, Canards, and Invariant Manifolds in the Phase-Resetting Response of Cardiac Pacemakers

    NASA Astrophysics Data System (ADS)

    Krogh-Madsen, Trine; Glass, Leon; Doedel, Eusebius; Guevara, Michael R.

    2004-03-01

    Injection of a brief stimulus pulse phase-resets the spontaneous periodic activity of cardiac pacemaker cells: an earlier stimulus generally delays the time of occurrence of the next action potential, while a later one causes an advance. We investigate a model with a fast upstroke velocity (representing a peripheral sinoatrial cell), where the transition from delay to advance appears discontinuous. Formulating the model as populations of single channels with pseudo-random open/close kinetics also reveal a discontinuity in the responses, as it is seen in experiments on some cardiac preparations. In a reduced three-dimensional version of the model we show that when the abrupt transition from delay to advance occurs, the state-point follows ``canard"-like trajectories that lie close to the slow manifold as well as the stable and unstable manifolds of the equilibrium point. Our results suggest that the phase-resetting response is fundamentally continuous, but extremely delicate, and thus demonstrate one way in which experiments might measure discontinuities in the resetting response of a nonlinear oscillator. As such, our results should be applicable to a large range of experimental situations.

  18. Multicellular automaticity of cardiac cell monolayers: effects of density and spatial distribution of pacemaker cells

    NASA Astrophysics Data System (ADS)

    Elber Duverger, James; Boudreau-Bland, Jonathan; Le, Minh Duc; Comtois, Philippe

    2014-11-01

    Self-organization of pacemaker (PM) activity of interconnected elements is important to the general theory of reaction-diffusion systems as well as for applications such as PM activity in cardiac tissue to initiate beating of the heart. Monolayer cultures of neonatal rat ventricular myocytes (NRVMs) are often used as experimental models in studies on cardiac electrophysiology. These monolayers exhibit automaticity (spontaneous activation) of their electrical activity. At low plated density, cells usually show a heterogeneous population consisting of PM and quiescent excitable cells (QECs). It is therefore highly probable that monolayers of NRVMs consist of a heterogeneous network of the two cell types. However, the effects of density and spatial distribution of the PM cells on spontaneous activity of monolayers remain unknown. Thus, a simple stochastic pattern formation algorithm was implemented to distribute PM and QECs in a binary-like 2D network. A FitzHugh-Nagumo excitable medium was used to simulate electrical spontaneous and propagating activity. Simulations showed a clear nonlinear dependency of spontaneous activity (occurrence and amplitude of spontaneous period) on the spatial patterns of PM cells. In most simulations, the first initiation sites were found to be located near the substrate boundaries. Comparison with experimental data obtained from cardiomyocyte monolayers shows important similarities in the position of initiation site activity. However, limitations in the model that do not reflect the complex beat-to-beat variation found in experiments indicate the need for a more realistic cardiomyocyte representation.

  19. Evaluation of the effects of electric fields on implanted cardiac pacemakers. Final report

    SciTech Connect

    Moss, A.J.; Carstensen, E.

    1985-02-01

    The effects of extra high voltage (EHV) transmission line electric fields on pacemaker function were evaluated in 11 patients with seven different implanted pacemaker models from four manufacturers. Alteration in pacemaker function was demonstrated in five unipolar units (three different models) from two manufacturers during exposure to electric fields ranging from 2 to 9 kV/m, with total body currents from 47 to 175 ..mu..A. These electric fields and body currents are representative of values that can be encountered by individuals standing beneath EHV transmission lines. Transient alterations in pacemaker function observed in this study included inappropriate triggered activity, inhibition of impulse generation, reduction in rate, and reversion from demand to asynchronous mode. Electromagnetic interference from high voltage transmission lines can induce alterations in pacemaker function in certain designs of these devices. However, pacemaker manufacturers can incorporate appropriate circuits in the pacemaker design to eliminate this problem. 8 references.

  20. Mechano-sensitivity of cardiac pacemaker function: pathophysiological relevance, experimental implications, and conceptual integration with other mechanisms of rhythmicity.

    PubMed

    Quinn, T Alexander; Kohl, Peter

    2012-01-01

    Cardiac pacemaker cells exhibit spontaneous, rhythmic electrical excitation, termed automaticity. This automatic initiation of action potentials requires spontaneous diastolic depolarisation, whose rate determines normal rhythm generation in the heart. Pacemaker mechanisms have been split recently into: (i) cyclic changes in trans-sarcolemmal ion flows (termed the 'membrane-clock'), and (ii) rhythmic intracellular calcium cycling (the 'calcium-clock'). These two 'clocks'undoubtedly interact, as trans-sarcolemmal currents involved in pacemaking include calcium-carrying mechanisms, while intracellular calcium cycling requires trans-sarcolemmal ion flux as the mechanism by which it affects membrane potential. The split into separate 'clocks' is, therefore, somewhat arbitrary. Nonetheless, the 'clock' metaphor has been conceptually stimulating, in particular since there is evidence to support the view that either 'clock'could be sufficient in principle to set the rate of pacemaker activation. Of course, the same has also been shown for sub-sets of 'membrane-clock' ion currents, illustrating the redundancy of mechanisms involved in maintaining such basic functionality as the heartbeat, a theme that is common for vital physiological systems. Following the conceptual path of identifying individual groups of sub-mechanisms, it is important to remember that the heart is able to adapt pacemaker rate to changes in haemodynamic load, even after isolation or transplantation, and on a beat-by-beat basis. Neither the 'membrane-' nor the 'calcium-clock' do, as such, inherently account for this rapid adaptation to circulatory demand (cellular Ca? balance changes over multiple beats, while variation of sarcolemmal ion channel presence takes even longer). This suggests that a third set of mechanisms must be involved in setting the pace. These mechanisms are characterised by their sensitivity to the cyclically changing mechanical environment, and--in analogy to the above terminology--this might be considered a 'mechanics-clock'. In this review, we discuss possible roles of mechano-sensitive mechanisms for the entrainment of membrane current dynamics and calcium-handling. This can occur directly via stretch-activation of mechano-sensitive ion channels in the sarcolemma and/or in intracellular membrane compartments, as well as by modulation of 'standard' components of the 'membrane-' or 'calcium-clock'. Together, these mechanisms allow rapid adaptation to changes in haemodynamic load, on a beat-by-beat basis. Additional relevance arises from the fact that mechano-sensitivity of pacemaking may help to explain pacemaker dysfunction in mechanically over- or under-loaded tissue. As the combined contributions of the various underlying oscillatory mechanisms are integrated at the pacemaker cell level into a single output--a train of pacemaker action potentials--we will not adhere to a metaphor that implies separate time-keeping units ('clocks'), and rather focus on cardiac pacemaking as the result of interactions of a set of coupled oscillators, whose individual contributions vary depending on the pathophysiological context. We conclude by considering the utility and limitations of viewing the pacemaker as a coupled system of voltage-, calcium-, and mechanics-modulated oscillators that, by integrating a multitude of inputs, offers the high level of functional redundancy that is vitally important for cardiac automaticity. PMID:23046620

  1. Mechano-sensitivity of cardiac pacemaker function: Pathophysiological relevance, experimental implications, and conceptual integration with other mechanisms of rhythmicity

    PubMed Central

    Quinn, T. Alexander; Kohl, Peter

    2012-01-01

    Cardiac pacemaker cells exhibit spontaneous, rhythmic electrical excitation, termed automaticity. This automatic initiation of action potentials requires spontaneous diastolic depolarisation, whose rate determines normal rhythm generation in the heart. Pacemaker mechanisms have been split recently into: (i) cyclic changes in trans-sarcolemmal ion flows (termed the membrane-clock), and (ii) rhythmic intracellular calcium cycling (the calcium-clock). These two clocks undoubtedly interact, as trans-sarcolemmal currents involved in pacemaking include calcium-carrying mechanisms, while intracellular calcium cycling requires trans-sarcolemmal ion flux as the mechanism by which it affects membrane potential. The split into separate clocks is, therefore, somewhat arbitrary. Nonetheless, the clock metaphor has been conceptually stimulating, in particular since there is evidence to support the view that either clock could be sufficient in principle to set the rate of pacemaker activation. Of course, the same has also been shown for sub-sets of membrane-clock ion currents, illustrating the redundancy of mechanisms involved in maintaining such basic functionality as the heartbeat, a theme that is common for vital physiological systems. Following the conceptual path of identifying individual groups of sub-mechanisms, it is important to remember that the heart is able to adapt pacemaker rate to changes in haemodynamic load, even after isolation or transplantation, and on a beat-by-beat basis. Neither the membrane- nor the calcium-clock do, as such, inherently account for this rapid adaptation to circulatory demand (cellular Ca2+ balance changes over multiple beats, while variation of sarcolemmal ion channel presence takes even longer). This suggests that a third set of mechanisms must be involved in setting the pace. These mechanisms are characterised by their sensitivity to the cyclically changing mechanical environment, and in analogy to the above terminology this might be considered a mechanics-clock. In this review, we discuss possible roles of mechano-sensitive mechanisms for the entrainment of membrane current dynamics and calcium-handling. This can occur directly via stretch-activation of mechano-sensitive ion channels in the sarcolemma and/or in intracellular membrane compartments, as well as by modulation of standard components of the membrane- or calcium-clock. Together, these mechanisms allow rapid adaptation to changes in haemodynamic load, on a beat-by-beat basis. Additional relevance arises from the fact that mechano-sensitivity of pacemaking may help to explain pacemaker dysfunction in mechanically over- or under-loaded tissue. As the combined contributions of the various underlying oscillatory mechanisms are integrated at the pacemaker cell level into a single output a train of pacemaker action potentials we will not adhere to a metaphor that implies separate time-keeping units (clocks), and rather focus on cardiac pacemaking as the result of interactions of a set of coupled oscillators, whose individual contributions vary depending on the pathophysiological context. We conclude by considering the utility and limitations of viewing the pacemaker as a coupled system of voltage-, calcium-, and mechanics-modulated oscillators that, by integrating a multitude of inputs, offers the high level of functional redundancy that is vitally important for cardiac automaticity. PMID:23046620

  2. Genetic Regulation of Sinoatrial Node Development and Pacemaker Program in the Venous Pole

    PubMed Central

    Ye, Wenduo; Song, Yingnan; Huang, Zhen; Zhang, Yanding; Chen, Yiping

    2015-01-01

    The definitive sinoatrial node (SAN), the primary pacemaker of the mammalian heart, develops from part of pro-pacemaking embryonic venous pole that expresses both Hcn4 and the transcriptional factor Shox2. It is noted that ectopic pacemaking activities originated from the myocardial sleeves of the pulmonary vein and systemic venous return, both derived from the Shox2+ pro-pacemaking cells in the venous pole, cause atrial fibrillation. However, the developmental link between the pacemaker properties in the embryonic venous pole cells and the SAN remains largely uncharacterized. Furthermore, the genetic program for the development of heterogeneous populations of the SAN is also under-appreciated. Here, we review the literature for a better understanding of the heterogeneous development of the SAN in relation to that of the sinus venosus myocardium and pulmonary vein myocardium. We also attempt to revisit genetic models pertinent to the development of pacemaker activities in the perspective of a Shox2-Nkx2-5 epistatic antagonism. Finally, we describe recent efforts in deciphering the regulatory networks for pacemaker development by genome-wide approaches. PMID:26682210

  3. Pulsed Nd:YAG laser welding of cardiac pacemaker batteries with reduced heat input

    SciTech Connect

    Fuerschbach, P.W.; Hinkley, D.A.

    1997-03-01

    The effects of Nd:YAG laser beam welding process parameters on the resulting heat input in 304L stainless steel cardiac pacemaker batteries have been studied. By careful selection of process parameters, the results can be used to reduce temperatures near glass-to-metal seals and assure hermeticity in laser beam welding of high reliability components. Three designed response surface experiments were used to compare welding performance with lenses of varying focal lengths. The measured peak temperatures at the glass-to-metal seals varied from 65 to 140 C (149 to 284 F) and depended strongly on the levels of the experimental factors. It was found that welds of equivalent size can be made with significantly reduced temperatures. The reduction in battery temperatures has been attributed to an increase in the melting efficiency. This increase is thought to be due primarily to increased travel speeds, which were facilitated by high peak powers and low pulse energies. For longer focal length lenses, weld fusion zone widths were found to be greater even without a corresponding increase in the size of the weld. It was also found that increases in laser beam irradiance either by higher peak powers or smaller spot sizes created deeper and larger welds. These gains were attributed to an increase in the laser energy transfer efficiency.

  4. Radiation effect on implanted pacemakers

    SciTech Connect

    Pourhamidi, A.H.

    1983-10-01

    It was previously thought that diagnostic or therapeutic ionizing radiation did not have an adverse effect on the function of cardiac pacemakers. Recently, however, some authors have reported damaging effect of therapeutic radiation on cardiac pulse generators. An analysis of a recently-extracted pacemaker documented the effect of radiation on the pacemaker pulse generator.

  5. Post-cardiac injury syndrome following transvenous pacemaker insertion: A case report and review of the literature.

    PubMed

    Cevik, Cihan; Wilborn, Troy; Corona, Rita; Schanzmeyer, Elizabeth; Nugent, Kenneth

    2009-12-01

    Post-cardiac injury syndrome is an inflammatory process involving the pleura and pericardium secondary to cardiac injury and can develop following transvenous pacemaker insertion. We now report a patient who developed this syndrome following dual-chamber pacemaker insertion with active fixation of the atrial and ventricular leads. The pericardial fluid was bloody and had a neutrophilic predominance. The pericardial biopsy revealed fibrinous pericarditis with a mixed inflammatory cell infiltrate. The pleural effusion was exudative and had a neutrophilic predominance. Nine similar cases were identified in the English literature dating back to 1975. These patients usually present within one month after pacemaker insertion. They have exudative pericardial and pleural effusions. The pericardial effusions can cause tamponade and may require treatment with either catheter drainage or a surgical window. Some of these patients respond well to anti-inflammatory medications, including prednisone. Therefore, early identification of these patients could allow medical treatment and might help avoid the need for a surgical procedure. Cardiologists should remember that this uncommon syndrome can occur after routine endovascular procedures. PMID:19647485

  6. Mechanisms of Beat-to-Beat Regulation of Cardiac Pacemaker Cell Function by Ca2+ Cycling Dynamics

    PubMed Central

    Yaniv, Yael; Stern, MichaelD.; Lakatta, EdwardG.; Maltsev, VictorA.

    2013-01-01

    Whether intracellular Ca2+ cycling dynamics regulate cardiac pacemaker cell function on a beat-to-beat basis remains unknown. Here we show that under physiological conditions, application of low concentrations of caffeine (24mM) to isolated single rabbit sinoatrial node cells acutely reduces their spontaneous action potential cycle length (CL) and increases Ca2+ transient amplitude for several cycles. Numerical simulations, using a modified Maltsev-Lakatta coupled-clock model, faithfully reproduced these effects, and also the effects of CL prolongation and dysrhythmic spontaneous beating (produced by cytosolic Ca2+ buffering) and an acute CL reduction (produced by flash-induced Ca2+ release from a caged Ca2+ buffer), which we had reported previously. Three contemporary numerical models (including the original Maltsev-Lakatta model) failed to reproduce the experimental results. In our proposed new model, Ca2+ releases acutely change the CL via activation of the Na+/Ca2+ exchanger current. Time-dependent CL reductions after flash-induced Ca2+ releases (the memory effect) are linked to changes in Ca2+ available for pumping into sarcoplasmic reticulum which, in turn, changes the sarcoplasmic reticulum Ca2+ load, diastolic Ca2+ releases, and Na+/Ca2+ exchanger current. These results support the idea that Ca2+ regulates CL in cardiac pacemaker cells on a beat-to-beat basis, and suggest a more realistic numerical mechanism of this regulation. PMID:24094396

  7. Changes in evoked QT intervals according to variations in atrioventricular delay and cardiac function in patients with implanted QT-driven DDDR pacemakers.

    PubMed

    Ishikawa, Toshiyuki; Sugano, Teruyasu; Sumita, Shinichi; Kosuge, Masami; Kobayashi, Izumi; Kobayashi, Tsukasa; Yamakawa, Yohei; Matsusita, Kohei; Matsumoto, Katsumi; Ohkusu, Yasuo; Uchino, Kazuaki; Kimura, Kazuo; Usui, Takashi; Umemura, Satoshi

    2003-06-01

    In patients with implanted DDD pacemaker, cardiac output is maximal when atrioventricular (AV) delay is set to give the maximum QT interval (QTI). QTI is used as a sensor of a rate-responsive pacemaker and the evoked QTI (eQTI) is measured as the time duration from the ventricular pace-pulse and the T sense point, which is the steepest point of the intracardiac T wave. The relationship between the changes in eQTI according to AV delay variations and cardiac function was studied in 13 patients (74.2+/-9.3 [SD] years old) with an implanted QT-driven DDDR-pacemaker. A special software module was downloaded into the pacemaker memory and a personal computer equipped with the special software was connected to the programmer for eQTI date-logging. AV delay was set at 100, 120, 150, 180 and 210 ms. Delta eQTI was defined as maximal eQTI - minimal eQTI. The ejection fraction (EF) was measured by echocardiography. When the AV delay was prolonged, eQTI gradually increased and reached a peak, and then decreased. Delta eQTI in patients with reduced cardiac function (EF <40%) was significantly greater than that in normal cardiac function (EF >55%, 7.6+/-4.9 vs 2.7+/-9.8 ms, p<0.05). There was significant negative correlation between EF and delta eQTI (r=-0.63, p<0.05). The peak of changes in eQTI according to AV delay variations was steeper in patients with reduced cardiac function than in those with normal cardiac function. In conclusion, changes in eQTI according to AV delay variation are greater in patients with reduced cardiac function than in those with normal cardiac function, and the AV delay that gives the maximal eQTI can be easily determined in patients with reduced cardiac function. PMID:12808269

  8. The influence of anatomical and physiological parameters on the interference voltage at the input of unipolar cardiac pacemakers in low frequency electric fields

    NASA Astrophysics Data System (ADS)

    Joosten, S.; Pammler, K.; Silny, J.

    2009-02-01

    The problem of electromagnetic interference of electronic implants such as cardiac pacemakers has been well known for many years. An increasing number of field sources in everyday life and occupational environment leads unavoidably to an increased risk for patients with electronic implants. However, no obligatory national or international safety regulations exist for the protection of this patient group. The aim of this study is to find out the anatomical and physiological worst-case conditions for patients with an implanted pacemaker adjusted to unipolar sensing in external time-varying electric fields. The results of this study with 15 volunteers show that, in electric fields, variation of the interference voltage at the input of a cardiac pacemaker adds up to 200% only because of individual factors. These factors should be considered in human studies and in the setting of safety regulations.

  9. The influence of anatomical and physiological parameters on the interference voltage at the input of unipolar cardiac pacemakers in low frequency electric fields.

    PubMed

    Joosten, S; Pammler, K; Silny, J

    2009-02-01

    The problem of electromagnetic interference of electronic implants such as cardiac pacemakers has been well known for many years. An increasing number of field sources in everyday life and occupational environment leads unavoidably to an increased risk for patients with electronic implants. However, no obligatory national or international safety regulations exist for the protection of this patient group. The aim of this study is to find out the anatomical and physiological worst-case conditions for patients with an implanted pacemaker adjusted to unipolar sensing in external time-varying electric fields. The results of this study with 15 volunteers show that, in electric fields, variation of the interference voltage at the input of a cardiac pacemaker adds up to 200% only because of individual factors. These factors should be considered in human studies and in the setting of safety regulations. PMID:19124951

  10. [Sport for pacemaker patients].

    PubMed

    Israel, C W

    2012-06-01

    Sport activity is an important issue in many patients with a pacemaker either because they performed sport activities before pacemaker implantation to reduce the cardiovascular risk or to improve the course of an underlying cardiovascular disease (e.g. coronary artery disease, heart failure) by sports. Compared to patients with an implantable cardioverter defibrillator (ICD) the risks from underlying cardiovascular disease (e.g. ischemia, heart failure), arrhythmia, lead dysfunction or inappropriate therapy are less important or absent. Sport is contraindicated in dyspnea at rest, acute heart failure, new complex arrhythmia, acute myocarditis and acute myocardial infarction, valvular disease with indications for intervention and surgery and comorbidities which prevent physical activity. Patients with underlying cardiovascular disease (including hypertension) should preferably perform types and levels of physical activity that are aerobic (with dynamic exercise) such as running, swimming, cycling instead of sport with high anaerobic demands and high muscular workload. In heart failure, studies demonstrated advantages of isometric sport that increases the amount of muscle, thereby preventing cardiac cachexia. Sport with a risk of blows to the chest or physical contact (e.g. boxing, rugby, martial arts) should be avoided. Implantation, programming and follow-up should respect specific precautions to allow optimal physical activity with a pacemaker including implantation of bipolar leads on the side contralateral to the dominant hand, individual programming of the upper sensor and tracking rate and regular exercise testing. PMID:22854824

  11. [Pacemaker longevity. Replacement of the device].

    PubMed

    Deharo, J C; Djiane, P

    2005-01-01

    Life expectancy of patients implanted with cardiac pacemakers has largely increased, so that generator replacement is becoming an important part of the activity in most of the implanting centers. In more than 70% of the cases, the indication for pacemaker replacement is normal battery depletion. Since the new devices are more and more sophisticated and smaller, longevity optimization becomes a real challenge. The main determinant of pacemaker longevity is the output programmed for the pulse generator. It mainly depends on the output voltage and duration settings. The pacing impedance and the percentage of time with pacing are other major determinants of pacemaker longevity. Each manufacturer provides specific policy but the battery voltage and internal impedance are the more accurate and easy-to-obtain battery depletion parameters. The magnet rate is still frequently used but is less valuable since it can drop abruptly at the end of battery life. The complication rate of pacemaker replacement is three-fold higher than the one of first implant. Infections, skin erosions and lead related complications are not uncommon. The replacement should be systematically preceded by the checking of several points including the patient's pacemaker dependency, the necessity to replace or extract one or several leads, the venous system status, the compatibility between the new generator and the leads and the necessity to upgrade the pacing system or to change the pacemaker pocket. PMID:15702908

  12. Cardiac pacemakers: design, function and problems. January, 1976-May, 1981 (citations from the International Information Service for the Physics and Engineering Communities data base). Report for January 1976-May 1981

    SciTech Connect

    Not Available

    1981-05-01

    This retrospective bibliography contains citations concerning the design, function, and problems of fixed rate and demand implanted cardiac pacemakers. The susceptibility of pacemakers to electromagnetic interference, and the effects of radiation therapy and microwave interception are considered. The reliability of batteries, types of batteries, and other power sources are all discussed. Nondestructive methods for the assessment of cells and pacemaker are included. (Contains 107 citations fully indexed and including a title list.)

  13. Performance of lithium-iodine and lithium-silver chromate cells in cardiac pacemakers

    SciTech Connect

    Luksha, E.

    1980-01-01

    Lithium battery powered pacemakers have been manufactured since November, 1972. The in-vivo performance of various solid state lithium-iodine cells of different designs and the non-aqueous lithium-silver chromate is described and compared with projected performance. It is reported that to date all types of cells have shown a perfect record. There has not been a confirmed battery failure. 4 refs.

  14. Implantable cardiac pacemaker electromagnetic compatibility testing in a novel security system simulator.

    PubMed

    Kainz, Wolfgang; Casamento, Jon P; Ruggera, Paul S; Chan, Dulciana D; Witters, Donald M

    2005-03-01

    This paper describes a novel simulator to perform electromagnetic compatibility (EMC) tests for active implantable medical devices (AIMDs) with electromagnetic fields emitted by security systems. The security system simulator was developed in response to over 100 incident reports over 17 years related to the interference of AIMD's with security systems and the lack of a standardized test method. The simulator was evaluated regarding field homogeneity, signal distortion, and maximum magnetic field strength levels. Small three-axis probes and a three-axis scanning system were designed to determine the spatial and temporal characteristics of the fields emitted by 12 different types of walk through metal detectors (WTMDs). Tests were performed on four implanted pacemakers with a saline phantom and correlated to a newly developed test method performed "in air" (without the phantom). Comparison of the simulator thresholds with tests performed in real WTMDs showed that the simulator is able to mimic the pacemaker interference. The interference thresholds found in the simulator indicate that pulsed magnetic fields are more likely to cause interference in pacemakers than sinusoidal fields. The security system simulator will help biomedical engineers, manufacturers of medical devices, and manufacturers of security systems to identify incompatible combinations of WTMDs and AIMDs early in the development stage. PMID:15759582

  15. Evaluation of patients' quality of life aspects after cardiac pacemaker implantation

    PubMed Central

    de Barros, Rubens Tofano; de Carvalho, Sebastião Marcos Ribeiro; Silva, Marcos Augusto de Moraes; Borges, Juliana Bassalobre Carvalho

    2014-01-01

    Objective To evaluate patients' quality of life aspects after pacemaker implantation, relating it to gender, age, and implantation timespan. Methods A total of 107 clinically stable patients of both genders (49.5% women and 50.5% men) over 18 years old (average 69.3±12.6 years) and presenting an implantation timespan of three to 12 months (average 6.36±2.99 months) were evaluated. The evaluation included personal, clinical, and implant data as well as quality of life questionnaires (AQUAREL and SF-36). Statistical analysis was conducted using the t test and Pearson correlation, with a 5% significance level. Results The lowest SF-36 score referred to physical aspects, and the highest score referred to social aspects. In AQUAREL, the lowest score referred to dyspnea, and the highest referred to discomfort. There was a significant association between gender and quality of life in SF-36 (physical functioning and emotional aspects) and in AQUAREL (dyspnea). A negative correlation was observed between age and quality of life (functional capacity in SF-36, and discomfort in AQUAREL) in relation to implantation timespan, a correlation with vitality from SF-36. Conclusion Lower quality of life scores were found in physical aspects and dyspnea; and higher scores in social aspects and discomfort. Men presented higher quality of life scores related to physical functioning, emotional aspects and dyspnea. As age increases, quality of life worsens regarding functional capacity and discomfort; and the longer the pacemaker implantation timespan, the worse quality of life when it comes to vitality. Gender, age, and implantation timespan influence quality of life; thus, these variables must be considered in strategies for improving quality of life of patients with pacemakers. PMID:24896161

  16. Common questions about pacemakers.

    PubMed

    Denay, Keri L; Johansen, Michael

    2014-02-15

    Pacemakers are indicated in patients with certain symptomatic bradyarrhythmias caused by sinus node dysfunction, and in those with frequent, prolonged sinus pauses. Patients with third-degree or complete atrioventricular (AV) block benefit from pacemaker placement, as do those with type II second-degree AV block because of the risk of progression to complete AV block. The use of pacemakers in patients with type I second-degree AV block is controversial. Patients with first-degree AV block generally should not receive a pacemaker except when the PR interval is significantly prolonged and the patient is symptomatic. Although some guidelines recommend pacemaker implantation for patients with hypersensitive carotid sinus syndrome, recent evidence has not shown benefit. Some older patients with severe neurocardiogenic syncope may benefit from pacemakers, but most patients with this disorder do not. Cardiac resynchronization therapy improves mortality rates and some other disease-specific measures in patients who have a QRS duration of 150 milliseconds or greater and New York Heart Association class III or IV heart failure. Patients with class II heart failure and a QRS of 150 milliseconds or greater also appear to benefit, but there is insufficient evidence to support the use of cardiac resynchronization therapy in patients with class I heart failure. Cardiac resynchronization therapy in patients with a QRS of 120 to 150 milliseconds does not reduce rates of hospitalization or death. PMID:24695448

  17. Dosimetric perturbations due to an implanted cardiac pacemaker in MammoSite{sup Registered-Sign} treatment

    SciTech Connect

    Sung, Wonmo; Kim, Siyong; Kim, Jung-in; Lee, Jae-gi; Shin, Young-Joo; Jung, Jae-Yong; Ye, Sung-Joon

    2012-10-15

    Purpose: To investigate dose perturbations for pacemaker-implanted patients in partial breast irradiation using high dose rate (HDR) balloon brachytherapy. Methods: Monte Carlo (MC) simulations were performed to calculate dose distributions involving a pacemaker in Ir-192 HDR balloon brachytherapy. Dose perturbations by varying balloon-to-pacemaker distances (BPD = 50 or 100 mm) and concentrations of iodine contrast medium (2.5%, 5.0%, 7.5%, and 10.0% by volume) in the balloon were investigated for separate parts of the pacemaker (i.e., battery and substrate). Relative measurements using an ion-chamber were also performed to confirm MC results. Results: The MC and measured results in homogeneous media without a pacemaker agreed with published data within 2% from the balloon surface to 100 mm BPD. Further their dose distributions with a pacemaker were in a comparable agreement. The MC results showed that doses over the battery were increased by a factor of 3, compared to doses without a pacemaker. However, there was no significant dose perturbation in the middle of substrate but up to 70% dose increase in the substrate interface with the titanium capsule. The attenuation by iodine contrast medium lessened doses delivered to the pacemaker by up to 9%. Conclusions: Due to inhomogeneity of pacemaker and contrast medium as well as low-energy photons in Ir-192 HDR balloon brachytherapy, the actual dose received in a pacemaker is different from the homogeneous medium-based dose and the external beam-based dose. Therefore, the dose perturbations should be considered for pacemaker-implanted patients when evaluating a safe clinical distance between the balloon and pacemaker.

  18. Electromagnetic interference from lasers and intense light sources in the treatment of patients with artificial pacemakers and other implantable cardiac devices.

    PubMed

    Lister, Tom; Grant, Lindsay; Lee, Siu-Man; Cole, Richard P; Jones, Anthony; Taylor, Timothy; Mayo, Angela; Wright, Philip A

    2015-07-01

    Measurements of the electric and magnetic field strengths surrounding six laser systems and one intense pulsed light system were carried out. The results were compared to exposure limits published by cardiac device manufacturers to assess the risk of electromagnetic interference to implantable cardiac devices such as pacemakers or implantable cardioverter defibrillators. The majority of lasers assessed in this study were found to produce electric and magnetic field strengths below the published exposure limits for cardiac devices. However, the low-frequency electric field and static magnetic field of both the CO2 laser and the ruby laser were found to exceed these limits. Ensuring that a small separation is maintained at all times between the laser unit and any patient with a pacemaker or implantable cardioverter defibrillator appears to be a sensible expedient in avoiding overexposure of an implantable cardiac device to electromagnetic interference. Due to the single-shot fast discharge nature of the intense pulsed light system, changes in electromagnetic field strength were too fast for some of the measuring equipment used in this study to register accurate readings during operation. PMID:24162308

  19. Radiography of Cardiac Conduction Devices: A Pictorial Review of Pacemakers and Implantable Cardioverter Defibrillators

    PubMed Central

    Torres-Ayala, Stephanie C; Santacana-Laffitte, Guido; Maldonado, Jos

    2014-01-01

    Cardiac conduction devices (CCDs) depend on correct anatomic positioning to function properly. Chest radiography is the preferred imaging modality to evaluate CCD's anatomic location, lead wire integrity, and help in identifying several complications. In this pictorial review, our goal is to familiarize radiologists with CCD implantation techniques, appropriate positioning of the device, common causes of malfunction, methods to improve report accuracy, and assure maximal therapeutic benefit. PMID:25806132

  20. A pilot study of a mindfulness based stress reduction program in adolescents with implantable cardioverter defibrillators or pacemakers.

    PubMed

    Freedenberg, Vicki A; Thomas, Sue A; Friedmann, Erika

    2015-04-01

    Adolescents with implantable cardioverter defibrillators (ICDs) or pacemakers (PMs) face unique challenges that can cause psychosocial distress. Psychosocial interventions are effective for adults with cardiac devices and could potentially impact adolescents' adjustment to these devices. Mindfulness Based Stress Reduction (MBSR) is a structured psycho-educational program that includes meditation, yoga, and group support and has been studied extensively among adults. This study examined the feasibility of the MBSR program for adolescents with ICDs/PMs, a population previously unexamined in the research literature. The participants completed measures of anxiety and depression (Hospital Anxiety and Depression Scale) and coping (Responses to Stress Questionnaire) at baseline and after the six-session MBSR intervention. Mean age of the cohort (n = 10) was 15 3 years, 6 were male, 6 had a PM, and 4 had an ICD. Feasibility was demonstrated by successful recruitment of 10 participants, 100 % participation and completion. Anxiety decreased significantly following the intervention, with a large effect size, t[9] = 3.67, p < .01, ? (2) = .59. Anxiety frequency decreased from baseline to post-intervention (Fisher's exact test p = .024), and 90 % of participants reported decreased anxiety scores post-intervention. Coping skills related negatively to anxiety (r = -.65, p = .04) and depression (r = -.88, p = .001). Post-intervention, the group independently formed their own Facebook group and requested to continue meeting monthly. Although generalizability is limited due to the small sample size, this successful pilot study paves the way for larger studies to examine the efficacy of MBSR interventions in adolescents with high-risk cardiac diagnoses. PMID:25519914

  1. Cardiac resynchronization therapy pacemaker: critical appraisal of the adaptive CRT-P device.

    PubMed

    Daoud, Georges E; Houmsse, Mahmoud

    2016-01-01

    Cardiac resynchronization therapy (CRT) is an effective and well-established therapy for patients suffering with heart failure, left ventricular (LV) systolic dysfunction (ejection fraction ?35%), and electrical dyssynchrony, demonstrated by a surface QRS duration of ?120 ms. Patients undergoing treatment with CRT have shown significant improvement in functional class, quality of life, LV ejection fraction, exercise capacity, hemodynamics, and reverse remodeling of LV, and ultimately, morbidity and mortality. However, 30%-40% of patients who receive a CRT device may not show improvement, and they are termed as non responders. The nonresponders have a poor prognosis; several methods have been developed to try to enhance response to CRT. Echocardiography-guided optimization of CRT has not resulted in significant clinical benefit, since it is done at rest with the patient in supine position. An ideal optimization strategy would provide continuous monitoring and adjustment of device pacing to provide maximal cardiac resynchronization, under a multitude of physiologic states. Intrinsic activation of the right ventricle (RV) with paced activation of the RV, even in the setting of biventricular (BiV) pacing, may result in an adverse effect on cardiac performance. With this physiology, the use of LV-only pacing may be preferred and may enhance CRT. Adaptive CRT is a novel device-based algorithm that was designed to achieve patient-specific adjustment in CRT so as to provide appropriate BiV pacing or LV-only pacing. This article will review the goals of CRT optimization, and implementation and outcomes associated with adaptive CRT. PMID:26848278

  2. Cardiac resynchronization therapy pacemaker: critical appraisal of the adaptive CRT-P device

    PubMed Central

    Daoud, Georges E; Houmsse, Mahmoud

    2016-01-01

    Cardiac resynchronization therapy (CRT) is an effective and well-established therapy for patients suffering with heart failure, left ventricular (LV) systolic dysfunction (ejection fraction ≤35%), and electrical dyssynchrony, demonstrated by a surface QRS duration of ≥120 ms. Patients undergoing treatment with CRT have shown significant improvement in functional class, quality of life, LV ejection fraction, exercise capacity, hemodynamics, and reverse remodeling of LV, and ultimately, morbidity and mortality. However, 30%–40% of patients who receive a CRT device may not show improvement, and they are termed as non responders. The nonresponders have a poor prognosis; several methods have been developed to try to enhance response to CRT. Echocardiography-guided optimization of CRT has not resulted in significant clinical benefit, since it is done at rest with the patient in supine position. An ideal optimization strategy would provide continuous monitoring and adjustment of device pacing to provide maximal cardiac resynchronization, under a multitude of physiologic states. Intrinsic activation of the right ventricle (RV) with paced activation of the RV, even in the setting of biventricular (BiV) pacing, may result in an adverse effect on cardiac performance. With this physiology, the use of LV-only pacing may be preferred and may enhance CRT. Adaptive CRT is a novel device-based algorithm that was designed to achieve patient-specific adjustment in CRT so as to provide appropriate BiV pacing or LV-only pacing. This article will review the goals of CRT optimization, and implementation and outcomes associated with adaptive CRT. PMID:26848278

  3. Women's compliance with cardiac rehabilitation programs.

    PubMed

    Ginzel, A R

    1996-01-01

    As the incidence of cardiovascular disease in women increases, the process of cardiac rehabilitation in women is becoming increasingly important to nurses. Specifically, the issue of women's compliance with cardiac rehabilitation needs to be addressed by nurses. Most past and current research on cardiac rehabilitation and compliance with rehabilitation programs has been conducted on male subjects and cannot be accurately generalized to the female population. This article reviews current literature which addresses the issues of heart disease in women, cardiac rehabilitation and compliance in the general population, gender differences in cardiac rehabilitation, and compliance of women in cardiac rehabilitation. PMID:8657707

  4. Pacemaker (image)

    MedlinePLUS

    A pacemaker is a small, battery-operated electronic device which is inserted under the skin to help the heart beat regularly and at an appropriate rate. The pacemaker has leads that travel through a large vein ...

  5. [Effects of intravenous electrodes of cardiac pacemakers. Clinical and plethysmographic approach].

    PubMed

    Glock, Y; Salvador-Mazenq, M; Boccalon, H; Vaislic, C; Puel, P

    1985-01-01

    The authors study the haemodynamics of the endovenous electrodes of cardiac stimulators (EE) in the light of clinical and plethysmographic investigations. Seven venous thromboses were observed out of 2,000 implantations of stimulators (0.35%). The risk increases with age 7th decade) and the presence of multiple EEs. The comparative plethysmography of a series of 22 normal young subjects and 28 old patients equipped with EEs demonstrates that the deep venous return in the upper limbs of a normal subject is better in a young person and in a dominant limb. In the subject equipped with an EE, distensibility is reduced. Temporary coagulation has its place in the treatment of these phlebites (heparin, followed by calciparin). Surgery to disobstruct or excise EE or fibrinolytics are only required exceptionally. PMID:4095148

  6. Numerical models based on a minimal set of sarcolemmal electrogenic proteins and an intracellular Ca2+ clock generate robust, flexible, and energy-efficient cardiac pacemaking

    PubMed Central

    Maltsev, Victor A.; Lakatta, Edward G.

    2015-01-01

    Recent evidence supports the idea that robust and, importantly, FLEXIBLE automaticity of cardiac pacemaker cells is conferred by a coupled system of membrane ion currents (an M-clock) and a sarcoplasmic reticulum (SR)-based Ca2+ oscillator (Ca2+clock) that generates spontaneous diastolic Ca2+ releases. This study identified numerical models of a human biological pacemaker that features robust and flexible automaticity generated by a minimal set of electrogenic proteins and a Ca2+clock. Following the Occams razor principle (principle of parsimony), M-clock components of unknown molecular origin were excluded from Maltsev-Lakatta pacemaker cell model and thirteen different model types of only 4 or 5 components were derived and explored by a parametric sensitivity analysis. The extended ranges of SR Ca2+ pumping (i.e. Ca2+clock performance) and conductance of ion currents were sampled, yielding a large variety of parameter combination, i.e. specific model sets. We tested each sets ability to simulate autonomic modulation of human heart rate (minimum rate of 50 to 70 bpm; maximum rate of 140 to 210 bpm) in response to stimulation of cholinergic and ?-adrenergic receptors. We found that only those models that include a Ca2+clock (including the minimal 4-parameter model ICaL+IKr+INCX+Ca2+clock) were able to reproduce the full range of autonomic modulation. Inclusion of If or ICaT decreased the flexibility, but increased the robustness of the models (a relatively larger number of sets did not fail during testing). The new models comprised of components with clear molecular identity (i.e. lacking IbNa & Ist) portray a more realistic pacemaking: A smaller Na+ influx is expected to demand less energy for Na+ extrusion. The new large database of the reduced coupled-clock numerical models may serve as a useful tool for the design of biological pacemakers. It will also provide a conceptual basis for a general theory of robust, flexible, and energy-efficient pacemaking based on realistic components. PMID:23507256

  7. Novel cardiac pacemaker-based human model of periodic breathing to develop real-time, pre-emptive technology for carbon dioxide stabilisation

    PubMed Central

    Baruah, Resham; Giannoni, Alberto; Willson, Keith; Manisty, Charlotte H; Mebrate, Yoseph; Kyriacou, Andreas; Yadav, Hemang; Unsworth, Beth; Sutton, Richard; Mayet, Jamil; Hughes, Alun D; Francis, Darrel P

    2014-01-01

    Background Constant flow and concentration CO2 has previously been efficacious in attenuating ventilatory oscillations in periodic breathing (PB) where oscillations in CO2 drive ventilatory oscillations. However, it has the undesirable effect of increasing end-tidal CO2, and ventilation. We tested, in a model of PB, a dynamic CO2 therapy that aims to attenuate pacemaker-induced ventilatory oscillations while minimising CO2 dose. Methods First, pacemakers were manipulated in 12 pacemaker recipients, 6 with heart failure (ejection fraction (EF)=23.77.3%) and 6 without heart failure, to experimentally induce PB. Second, we applied a real-time algorithm of pre-emptive dynamic exogenous CO2 administration, and tested different timings. Results We found that cardiac output alternation using pacemakers successfully induced PB. Dynamic CO2 therapy, when delivered coincident with hyperventilation, attenuated 57% of the experimentally induced oscillations in end-tidal CO2: SD/mean 0.060.01 untreated versus 0.040.01 with treatment (p<0.0001) and 0.020.01 in baseline non-modified breathing. This translated to a 56% reduction in induced ventilatory oscillations: SD/mean 0.190.09 untreated versus 0.140.06 with treatment (p=0.001) and 0.100.03 at baseline. Of note, end-tidal CO2 did not significantly rise when dynamic CO2 was applied to the model (4.840.47 vs 4.91 0.45?kPa, p=0.08). Furthermore, mean ventilation was also not significantly increased by dynamic CO2 compared with untreated (7.81.2 vs 8.41.2?L/min, p=0.17). Conclusions Cardiac pacemaker manipulation can be used to induce PB experimentally. In this induced PB, delivering CO2 coincident with hyperventilation, ventilatory oscillations can be substantially attenuated without a significant increase in end-tidal CO2 or ventilation. Dynamic CO2 administration might be developed into a clinical treatment for PB. Trial Registration number ISRCTN29344450. PMID:25332798

  8. Biological pacemakers.

    PubMed

    Rajesh, G; Francis, Johnson

    2006-01-01

    Genetically engineered pacemakers could be a possible alternative to implantable electronic devices for the treatment of bradyarrhythmias. The strategies include upregulation of beta adrenergic receptors, conversion of myocytes into pacemaker cells and stem cell therapy. Pacemaker activity in adult ventricular myocytes is normally repressed by the inward rectifier potassium current (I(K1)). The I(K1) current is encoded by the Kir2 gene family. Use of a negative construct that suppresses current when expressed with wild-type Kir2.1 is an experimental approach for genesis of genetic pacemaker. Hyperpolarisation activated cyclic nucleotide gated (HCN) channels which generate If current, the pacemaker current of heart can be delivered to heart by using stem cell therapy approach and viral vectors. The unresolved issues include longevity and stability of pacemaker genes, limitations involved in adenoviral and stem cell therapy and creation of genetic pacemakers which can compete with the electronic units. PMID:16943888

  9. Crosstalk between Mitochondrial and Sarcoplasmic Reticulum Ca2+ Cycling Modulates Cardiac Pacemaker Cell Automaticity

    PubMed Central

    Yaniv, Yael; Spurgeon, Harold A.; Lyashkov, Alexey E.; Yang, Dongmei; Ziman, Bruce D.; Maltsev, Victor A.; Lakatta, Edward G.

    2012-01-01

    Background Mitochondria dynamically buffer cytosolic Ca2+ in cardiac ventricular cells and this affects the Ca2+ load of the sarcoplasmic reticulum (SR). In sinoatrial-node cells (SANC) the SR generates periodic local, subsarcolemmal Ca2+ releases (LCRs) that depend upon the SR load and are involved in SANC automaticity: LCRs activate an inward Na+-Ca2+ exchange current to accelerate the diastolic depolarization, prompting the ensemble of surface membrane ion channels to generate the next action potential (AP). Objective To determine if mitochondrial Ca2+ (Ca2+m), cytosolic Ca2+ (Ca2+c)-SR-Ca2+ crosstalk occurs in single rabbit SANC, and how this may relate to SANC normal automaticity. Results Inhibition of mitochondrial Ca2+ influx into (Ru360) or Ca2+ efflux from (CGP-37157) decreased [Ca2+]m to 808% control or increased [Ca2+]m to 1197% control, respectively. Concurrent with inhibition of mitochondrial Ca2+ influx or efflux, the SR Ca2+ load, and LCR size, duration, amplitude and period (imaged via confocal linescan) significantly increased or decreased, respectively. Changes in total ensemble LCR Ca2+ signal were highly correlated with the change in the SR Ca2+ load (r2?=?0.97). Changes in the spontaneous AP cycle length (Ru360, 1111% control; CGP-37157, 892% control) in response to changes in [Ca2+]m were predicted by concurrent changes in LCR period (r2?=?0.84). Conclusion A change in SANC Ca2+m flux translates into a change in the AP firing rate by effecting changes in Ca2+c and SR Ca2+ loading, which affects the characteristics of spontaneous SR Ca2+ release. PMID:22666369

  10. Role of sinoatrial node architecture in maintaining a balanced source-sink relationship and synchronous cardiac pacemaking.

    PubMed

    Unudurthi, Sathya D; Wolf, Roseanne M; Hund, Thomas J

    2014-01-01

    Normal heart rhythm (sinus rhythm) depends on regular activity of the sinoatrial node (SAN), a heterogeneous collection of specialized myocytes in the right atrium. SAN cells, in general, possess a unique electrophysiological profile that promotes spontaneous electrical activity (automaticity). However, while automaticity is required for normal pacemaking, it is not necessarily sufficient. Less appreciated is the importance of the elaborate structure of the SAN complex for proper pacemaker function. Here, we review the important structural features of the SAN with a focus on how these elements help manage a precarious balance between electrical charge generated by the SAN ("source") and the charge needed to excite the surrounding atrial tissue ("sink"). We also discuss how compromised "source-sink" balance due, for example to fibrosis, may promote SAN dysfunction, characterized by slow and/or asynchronous pacemaker activity and even failure, in the setting of cardiovascular disease (e.g., heart failure, atrial fibrillation). Finally, we discuss implications of the "source-sink" balance in the SAN complex for cell and gene therapies aimed at creating a biological pacemaker as replacement or bridge to conventional electronic pacemakers. PMID:25505419

  11. Role of sinoatrial node architecture in maintaining a balanced source-sink relationship and synchronous cardiac pacemaking

    PubMed Central

    Unudurthi, Sathya D.; Wolf, Roseanne M.; Hund, Thomas J.

    2014-01-01

    Normal heart rhythm (sinus rhythm) depends on regular activity of the sinoatrial node (SAN), a heterogeneous collection of specialized myocytes in the right atrium. SAN cells, in general, possess a unique electrophysiological profile that promotes spontaneous electrical activity (automaticity). However, while automaticity is required for normal pacemaking, it is not necessarily sufficient. Less appreciated is the importance of the elaborate structure of the SAN complex for proper pacemaker function. Here, we review the important structural features of the SAN with a focus on how these elements help manage a precarious balance between electrical charge generated by the SAN (source) and the charge needed to excite the surrounding atrial tissue (sink). We also discuss how compromised source-sink balance due, for example to fibrosis, may promote SAN dysfunction, characterized by slow and/or asynchronous pacemaker activity and even failure, in the setting of cardiovascular disease (e.g., heart failure, atrial fibrillation). Finally, we discuss implications of the source-sink balance in the SAN complex for cell and gene therapies aimed at creating a biological pacemaker as replacement or bridge to conventional electronic pacemakers. PMID:25505419

  12. Large Controlled Observational Study on Remote Monitoring of Pacemakers and Implantable Cardiac Defibrillators: A Clinical, Economic, and Organizational Evaluation

    PubMed Central

    2016-01-01

    Background Patients with implantable devices such as pacemakers (PMs) and implantable cardiac defibrillators (ICDs) should be followed up every 3–12 months, which traditionally required in-clinic visits. Innovative devices allow data transmission and technical or medical alerts to be sent from the patient's home to the physician (remote monitoring). A number of studies have shown its effectiveness in timely detection and management of both clinical and technical events, and endorsed its adoption. Unfortunately, in daily practice, remote monitoring has been implemented in uncoordinated and rather fragmented ways, calling for a more strategic approach. Objective The objective of the study was to analyze the impact of remote monitoring for PM and ICD in a “real world” context compared with in-clinic follow-up. The evaluation focuses on how this service is carried out by Local Health Authorities, the impact on the cardiology unit and the health system, and organizational features promoting or hindering its effectiveness and efficiency. Methods A multi-center, multi-vendor, controlled, observational, prospective study was conducted to analyze the impact of remote monitoring implementation. A total of 2101 patients were enrolled in the study: 1871 patients were followed through remote monitoring of PM/ICD (I-group) and 230 through in-clinic visits (U-group). The follow-up period was 12 months. Results In-clinic device follow-ups and cardiac visits were significantly lower in the I-group compared with the U-group, respectively: PM, I-group = 0.43, U-group = 1.07, P<.001; ICD, I-group = 0.98, U-group = 2.14, P<.001. PM, I-group = 0.37, U-group = 0.85, P<.001; ICD, I-group = 1.58, U-group = 1.69, P=.01. Hospitalizations for any cause were significantly lower in the I-group for PM patients only (I-group = 0.37, U-group = 0.50, P=.005). There were no significant differences regarding use of the emergency department for both PM and ICD patients. In the I-group, 0.30 (PM) and 0.37 (ICD) real clinical events per patient per year were detected within a mean (SD) time of 1.18 (2.08) days. Mean time spent by physicians to treat a patient was lower in the I-group compared to the U-group (-4.1 minutes PM; -13.7 minutes ICD). Organizational analysis showed that remote monitoring implementation was rather haphazard and fragmented. From a health care system perspective, the economic analysis showed statistically significant gains (P<.001) for the I-group using PM. Conclusions This study contributes to build solid evidence regarding the usefulness of RM in detecting and managing clinical and technical events with limited use of manpower and other health care resources. To fully gain the benefits of RM of PM/ICD, it is vital that organizational processes be streamlined and standardized within an overarching strategy. PMID:26764170

  13. Insertion and Management of Temporary Pacemakers.

    PubMed

    Sullivan, Breandan Lawrence; Bartels, Karsten; Hamilton, Natalie

    2016-03-01

    Temporary pacemakers are used in a variety of critical care settings. These life-saving devices are reviewed in 2 major categories in this review: first, the insertion and management of epicardial pacemakers after and during cardiac surgery; and second, the insertion of transvenous temporary pacemakers for the emergent treatment of bradyarrhythmias. Temporary epicardial pacemakers are used routinely in patients recovering from cardiac surgery. Borrowing from advances in cardiac resynchronization therapy there are many theoretical and untested benefits to pacing the postoperative cardiac surgery patient. Temporary transvenous pacing is traditionally an emergency procedure to stabilize patients suffering from hemodynamically unstable bradyarrhythmia. We review the traditional and expanding use of transvenous pacemakers inside and outside the operating room. PMID:26134176

  14. Mechanisms of Heart Block after Transcatheter Aortic Valve Replacement – Cardiac Anatomy, Clinical Predictors and Mechanical Factors that Contribute to Permanent Pacemaker Implantation

    PubMed Central

    Young Lee, Mark; Chilakamarri Yeshwant, Srinath; Chava, Sreedivya; Lawrence Lustgarten, Daniel

    2015-01-01

    Transcatheter aortic valve replacement (TAVR) has emerged as a valuable, minimally invasive treatment option in patients with symptomatic severe aortic stenosis at prohibitive or increased risk for conventional surgical replacement. Consequently, patients undergoing TAVR are prone to peri-procedural complications including cardiac conduction disturbances, which is the focus of this review. Atrioventricular conduction disturbances and arrhythmias before, during or after TAVR remain a matter of concern for this high-risk group of patients, as they have important consequences on hospital duration, short- and long-term medical management and finally on decisions of device-based treatment strategies (pacemaker or defibrillator implantation). We discuss the mechanisms of atrioventricular disturbances and characterise predisposing factors. Using validated clinical predictors, we discuss strategies to minimise the likelihood of creating permanent high-grade heart block, and identify factors to expedite the decision to implant a permanent pacemaker when the latter is unavoidable. We also discuss optimal pacing strategies to mitigate the possibility of pacing-induced cardiomyopathy. PMID:26835105

  15. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 2 2014-10-01 2014-10-01 false Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage. 410.49 Section 410.49 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM SUPPLEMENTARY MEDICAL INSURANCE (SMI) BENEFITS Medical and...

  16. Heart pacemaker

    MedlinePLUS

    ... implanted today can also work as implantable cardioverter defibrillators (ICD), which restore a normal heartbeat. ... Swerdlow CD, Zipes DP. Pacemakers and implantable cardioverter-defibrillators. In: Mann DL, Zipes DP, Libby P, Bonow ...

  17. Lithium pacemaker batteries - an overview

    SciTech Connect

    Liang, C.C.; Holmes, C.F.

    1980-01-01

    Batteries used as power sources in cardiac pacemakers are expected to have high energy density, long storage and operating life and high reliability. They must be nonhazardous under normal operating as well as abusive conditions. Intensive research activities on the past 10-15 years have resulted in the development of a variety of high energy density batteries using Li as the anode material (Li-batteries). At least six different chemical systems with Li anodes are in use as power sources for cardiac pacemakers. Some basic characteristics of these systems are discussed. 11 refs.

  18. Pacemakers (Beyond the Basics)

    MedlinePLUS

    ... aging of heart muscle TEMPORARY AND PERMANENT PACEMAKERS — Artificial pacemakers are electronic devices that stimulate the heart ... rhythms. There are many situations in which an artificial pacemaker may be recommended. Most commonly, a pacemaker ...

  19. [Latest results of treatment with pacemaker and implantable cardioverter defibrillators].

    PubMed

    Merkely, Bla

    2005-05-15

    Device-based anti-arrhythmic therapy is one of the most dynamically evolving branches of the medicine. Brady- and tachyarrhythmias can be treated efficiently and cost-effective with current pacemakers and ICDs. Beside conventional indications new indications have appeared in the last years: resynchronization treatment of severe congestive heart failure with biventricular pacing, primary prevention of sudden cardiac death with ICD, reduction of intraventricular gradient in hypertrophic obstructive cardiomyopathy. Several large clinical studies have investigated the efficacy of treatment in conventional indications, so the role of pacemaker therapy in carotid sinus hyperaesthesia or sinus node disease has been elucidated. Newer studies are trying to clarify the type or programming of the pacemaker in a given indication: physiological pacemakers have a more beneficial effect on the quality of life and decrease the incidence of atrial fibrillation. The implanted devices have frequency adaptation with new sensors, and they are even able to detect heart failure in an early phase. In the near future the number of pacemaker and ICD implantations will grow exponentially based on current trend. This will be due to the aging population, the simplification and increasing safety of implantation, and the widening of the indications for antiarrhythmic device implantation. PMID:15945237

  20. Modern pacemakers: hope or hype?

    PubMed

    DAS, Mithilesh K; Dandamudi, Gopi; Steiner, Hillel A

    2009-09-01

    In recent years, the role of implantable pacing devices has expanded beyond the arrhythmia horizon and contemporary pacemakers' attempt to meet the physiological needs of patients. Modern pacemakers' functions include various modes of dual-chamber pacing, rate-response algorithms with dual sensors for optimum physiological response, cardiac resynchronization therapy (CRT), arrhythmia-prevention algorithms, antitachycardia pacing, and hemodynamic monitoring. The automaticity features of pacemakers enable continuous or intermittent monitoring of various pacemaker parameters including battery voltage, pacing impedance, sensing levels, pacing thresholds, and daily activity log. Modern pacemakers offer "physiological pacing" algorithms that minimize ventricular pacing and reduce the incidence of atrial fibrillation significantly. Ventricular pacing in patients with intact atrioventricular (AV) conduction or intermittent advanced AV block should be minimized with a hope to reduce heart failure hospitalization and mortality. A reduction in all-cause mortality due to physiological pacing, except for the CRT, has yet to be demonstrated in a randomized trial. Overall, modern pacemakers have acceptable performances to fulfill the clinical needs and have a reasonable safety margin. Promising new technologies are currently under development and offer hope to patients who may one day derive both symptomatic and mortality benefit from these devices. PMID:19719501

  1. The nuclear pacemaker: Is renewed interest warranted

    SciTech Connect

    Parsonnet, V.; Berstein, A.D.; Perry, G.Y. )

    1990-10-01

    From 1973 through 1987, 155 radioisotope-powered nuclear pacemakers were implanted in 132 patients at the Newark Beth Israel Medical Center. The longevity of the first 15 devices, all of which were fixed-rate (VOO) pacemakers, was significantly better than that of 15 lithium-chemistry demand (VVI) pacemakers used as control devices (p = 0.0002). Of the entire cohort of 155 nuclear pacemakers, 136 were VVI devices and 19 were VOO units. The patients with VOO pacemakers needed reoperations more often than did those with VVI pacemakers, chiefly for mode change (p less than 0.001). Power-source failure was observed in only 1 case, but 47 nuclear pacemakers were removed for other reasons, including component malfunction (15 units), mode change (12 units), high pacing thresholds (8 units) and lead or connector problems (5 units). The actuarial survival at 15 years was 99% for power sources and 82% for the entire pacing systems (pulse generators plus leads). The frequency of malignancy was similar to that of the population at large and primary tumor sites were randomly distributed. Deaths most commonly were due to cardiac causes (68%). Thus, nuclear pacemakers are safe and reliable and their greater initial cost appears to be offset by their longevity and the resulting decrease in the frequency of reoperations. It is reasonable to suggest that further use be made of long-lasting nuclear power sources for modern pacemakers and other implantable rhythm-management devices.

  2. Cardiac phase: Amplitude analysis using macro programming

    SciTech Connect

    Logan, K.W.; Hickey, K.A.

    1981-11-01

    The analysis of EKG gated radionuclide cardiac imaging data with Fourier amplitude and phase images is becoming a valuable clinical technique, demonstrating location, size, and severity of regional ventricular abnormalities. Not all commercially available nuclear medicine computer systems offer software for phase and amplitude analysis; however, many systems do have the capability of linear image arithmetic using simple macro commands which can easily be sequenced into stored macro-strings or programs. Using simple but accurate series approximations for the Fourier operations, macro programs have been written for a Digital Equipment Corporation Gamma-11 system to obtain phase and amplitude images from routine gated cardiac studies. In addition, dynamic cine-mode presentation of the onset of mechanical systole is generated from the phase data, using only a second set of macro programs. This approach is easily adapted to different data acquisition protocols, and can be used on any system with macro commands for image arithmetic. Key words: Fourier analysis, cardiac cycle, gated blood pool imaging, amplitude image, phase image

  3. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... furnishes cardiac rehabilitation and has shown, in peer-reviewed published research, that it improves... rehabilitation program, a program must demonstrate through peer-reviewed, published research that it has... through peer-reviewed published research that it accomplished a statistically significant reduction in...

  4. Intraoperative pacemaker failure in an infant.

    PubMed

    Bailey, A G; Lacey, S R

    1991-10-01

    Pacemakers in children can present clinical challenges during surgery. We present a case report of an infant whose pacemaker reverted to a backup mode when electrocautery was used during surgery. The resulting bradycardia did not respond either to a magnet placed over the generator or to iv atropine. The circulation was supported by isoproterenol until the pacemaker was re-programmed by the manufacturer. Such devices require care and understanding if problems during surgery are to be avoided. PMID:1742829

  5. [Final arrest of a pacemaker after use of electrocautery].

    PubMed

    Delhumeau, A; Ronceray, S; Moreau, X; Cottineau, C; Cavellat, M

    1988-01-01

    A case is reported of irreversible damage being caused to a permanent programmable pacemaker by electrocautery used in the epigastric region. The pacemaker was rapidly replaced, and the patient had no adverse effects of this accident. The use of monopolar electrocautery in patients who have one of the new generation of programmable pacemakers is very dangerous. Bipolar forceps can reduce the level of interference between electrocautery units and pacemaker electrodes. With programmable pacemakers, the generator instruction manual should be consulted before surgery, as placing a magnet on the generator may not necessarily convert it to the asynchronous mode. When the use of electrocautery is unavoidable, external cardiac pacing electrodes should be placed on the patient, with an external cardiac pacemaker ready. PMID:3364815

  6. A Programmable Implantable Microstimulator SoC With Wireless Telemetry: Application in Closed-Loop Endocardial Stimulation for Cardiac Pacemaker.

    PubMed

    Shuenn-Yuh Lee; Su, M Y; Ming-Chun Liang; You-Yin Chen; Cheng-Han Hsieh; Chung-Min Yang; Hsin-Yi Lai; Jou-Wei Lin; Qiang Fang

    2011-12-01

    A low-power, wireless, and implantable microstimulator system on chip with smart powering management, immediate neural signal acquisition, and wireless rechargeable system is proposed. A system controller with parity checking handles the adjustable stimulus parameters for the stimulated objective. In the current paper, the rat's intra-cardiac electrogram is employed as the stimulated model in the animal study, and it is sensed by a low-voltage and low-power monitoring analog front end. The power management unit, which includes a rectifier, battery charging and detection, and a regulator, is used for the power control of the internal circuits. The stimulation data and required clock are extracted by a phase-locked-loop-based phase shift keying demodulator from an inductive AC signal. The full chip, which consumes 48 ?W only, is fabricated in a TSMC 0.35 ?m 2P4M standard CMOS process to perform the monitoring and pacing functions with inductively powered communication in the in vivo study. PMID:23852549

  7. Pacemaker insertion

    PubMed Central

    Kotsakou, Maria; Kioumis, Ioannis; Lazaridis, George; Pitsiou, Georgia; Lampaki, Sofia; Papaiwannou, Antonis; Karavergou, Anastasia; Tsakiridis, Kosmas; Katsikogiannis, Nikolaos; Karapantzos, Ilias; Karapantzou, Chrysanthi; Baka, Sofia; Mpoukovinas, Ioannis; Karavasilis, Vasilis; Rapti, Aggeliki; Trakada, Georgia; Zissimopoulos, Athanasios; Zarogoulidis, Konstantinos

    2015-01-01

    A pacemaker (PM) (or artificial PM, so as not to be confused with the hearts natural PM) is a medical device that uses electrical impulses, delivered by electrodes contracting the heart muscles, to regulate the beating of the heart. The primary purpose of this device is to maintain an adequate heart rate, either because the hearts natural PM is not fast enough, or there is a block in the hearts electrical conduction system. Modern PMs are externally programmable and allow the cardiologist to select the optimum pacing modes for individual patients. Some combine a PM and defibrillator in a single implantable device. PMs can be temporary or permanent. Temporary PMs are used to treat short-term heart problems, such as a slow heartbeat thats caused by a heart attack, heart surgery, or an overdose of medicine. Permanent PMs are used to control long-term heart rhythm problems. A PM can relieve some arrhythmia symptoms, such as fatigue and fainting. A PM also can help a person who has abnormal HRs resume a more active lifestyle. In the current mini review we will focus on the insertion of a PM and the possible pneumothorax that can be caused. PMID:25815303

  8. Successful emergency cardiac pacing and permanent pacemaker insertion in a preterm 29-week gestation hydropic baby with congenital complete heart block.

    PubMed

    Beake, Matthew Jonathan; Bhole, Vinay; Johnston, Tracey; Rasiah, Shree Vishna

    2015-02-01

    A preterm 29-week gestation baby was delivered because of gross foetal hydrops secondary to congenital complete heart block. Despite a poor prognosis, she survived stabilisation and received emergency epicardial pacing followed by permanent pacemaker insertion on day 13, weighing 1.2 kg. PMID:24984226

  9. Pacemakers and implantable cardioverter defibrillators--general and anesthetic considerations.

    PubMed

    Rapsang, Amy G; Bhattacharyya, Prithwis

    2014-01-01

    A pacemaking system consists of an impulse generator and lead or leads to carry the electrical impulse to the patient's heart. Pacemaker and implantable cardioverter defibrillator codes were made to describe the type of pacemaker or implantable cardioverter defibrillator implanted. Indications for pacing and implantable cardioverter defibrillator implantation were given by the American College of Cardiologists. Certain pacemakers have magnet-operated reed switches incorporated; however, magnet application can have serious adverse effects; hence, devices should be considered programmable unless known otherwise. When a device patient undergoes any procedure (with or without anesthesia), special precautions have to be observed including a focused history/physical examination, interrogation of pacemaker before and after the procedure, emergency drugs/temporary pacing and defibrillation, reprogramming of pacemaker and disabling certain pacemaker functions if required, monitoring of electrolyte and metabolic disturbance and avoiding certain drugs and equipments that can interfere with pacemaker function. If unanticipated device interactions are found, consider discontinuation of the procedure until the source of interference can be eliminated or managed and all corrective measures should be taken to ensure proper pacemaker function should be done. Post procedure, the cardiac rate and rhythm should be monitored continuously and emergency drugs and equipments should be kept ready and consultation with a cardiologist or a pacemaker-implantable cardioverter defibrillator service may be necessary. PMID:24907883

  10. [Pacemakers 16 years later].

    PubMed

    Dodinot, B

    1976-01-01

    In 1976, 10 years after the first successful implantations, the pacemaker technique is perfectly well accepted. Transvenous placement of the electrode is preferred in 95 % of the cases. Besides the 15 years nuclear power pacers (1970), conventional mercury pacemakers may reach a longevity of 4 to 5 years because of the reduction of the current drain. Lithium iodine seems a very promising source of energy. The mini-pacemakers with various iodine anodes are particularly attractive. The future is probably a well designed medium sized lithium pacemaker lasting more than 7 years. Patient follow-up is very much improved. All pacemakers exhibit an obvious rate reduction when their source of energy runs down. Therefore general practitioner and even the patients may detect this symptom. The main problem remains the lead resistance. The reduction of the frequency of pacemaker replacements and of the medical check-up makes life more simple for the pacemaker patient. PMID:1087802

  11. Effects of Lifestyle Modification Programs on Cardiac Risk Factors

    PubMed Central

    Razavi, Moaven; Fournier, Stephen; Shepard, Donald S.; Ritter, Grant; Strickler, Gail K.; Stason, William B.

    2014-01-01

    Medicare conducted a payment demonstration to evaluate the effectiveness of two intensive lifestyle modification programs in patients with symptomatic coronary artery disease: the Dr. Dean Ornish Program for Reversing Heart Disease (Ornish) and Cardiac Wellness Program of the Benson-Henry Mind Body Institute. This report describes the changes in cardiac risk factors achieved by each program during the active intervention year and subsequent year of follow-up. The demonstration enrolled 580 participants who had had an acute myocardial infarction, had undergone coronary artery bypass graft surgery or percutaneous coronary intervention within 12 months, or had documented stable angina pectoris. Of these, 98% completed the intense 3-month intervention, 71% the 12-month intervention, and 56% an additional follow-up year. Most cardiac risk factors improved significantly during the intense intervention period in both programs. Favorable changes in cardiac risk factors and functional cardiac capacity were maintained or improved further at 12 and 24 months in participants with active follow-up. Multivariable regressions found that risk-factor improvements were positively associated with abnormal baseline values, Ornish program participation for body mass index and systolic blood pressure, and with coronary artery bypass graft surgery. Expressed levels of motivation to lose weight and maintain weight loss were significant independent predictors of sustained weight loss (p?=?0.006). Both lifestyle modification programs achieved well-sustained reductions in cardiac risk factors. PMID:25490202

  12. Program for cardiac patients: stress testing and training.

    PubMed

    Lowenthal, S L; McAllister, R G

    1976-10-01

    Dynamic exercise stress testing had become a widely accepted technique in the diagnosis of cardiac patients. The results of standardized exercise testing may be used to evaluate a patient's functional capacity and to derive an exercise prescription to assist him in improving his state of cardiovascular fitness. Because the physical therapist has special training and skill in exercise-related techniques, a stress testing laboratory and an exercise-based cardiac rehabilitation program may be appropriately established in a hospital's physical therapy department. Results are presented of a diagnostic exercise testing and an exercise-based cardiac rehabilitation program organized and supervised by physical therapists in a 300-bed private hospital. PMID:967937

  13. [Treatment of bradycardias - who needs a pacemaker?].

    PubMed

    Seiler, Jens

    2014-02-01

    Bradyarrhythmias are caused by a disturbed impulse formation in the sinus node and/or a disturbed impulse conduction and can be subclassified clinically as sinus node dysfunction, atrioventricular (AV) block, or functional bradycardia. Persistent bradycardia can be diagnosed by standard ECG. For diagnosis of intermittent bradycardia, often long-term ECG monitoring and/or additional testing is necessary. Symptomatic bradycardias are the standard indication for cardiac pacing after exclusion of reversible causes. Since sinus node dysfunction is associated with a good prognosis, pacing in this condition is only indicated in the presence of bradycardia-related symptoms. For prognostic reasons, pacemaker implantation is indicated in third degree AV block and second degree AV block Mobitz Type II, even if asymptomatic. Cardiac pacing for recurrent unpredictable neurocardiogenic syncope due to a cardioinhibitory reflex should be considered in certain circumstances. The implantation of cardiac pacemakers has been performed for more than half of a century. Due to the enormous technological progress, pacemaker implantations can nowadays be performed under local anesthesia in an outpatient setting. However, complications of pacemaker therapy are still not uncommon. PMID:24463380

  14. ''Fine tuning'' programmable pacemakers using the MUGA study

    SciTech Connect

    Videen, J.S.; Huang, S.K.; Bazgan, I.D.; Mechling, E.; Patton, D.D.

    1985-05-01

    Programmable pacemakers (PPM) can be programmed to sense, stimulate, or inhibit atrial (A) and/or ventricular (V) electrical activity, and include variable A-V delays and other options. Selecting the optimum combination of settings for an individual patient can be a formidable task in the absence of noninvasive, objective, quantifiable measures of cardiac function. The authors attempt to determine whether the MUGA study could be adapted to such a task. MUGA studies were performed on 13 patients (pts) with PPM who had varying degrees of A-V block, during various settings of the PPM's. Studies were carried out 5-10 min. after pacing mode and A-V delay were changed, with the pt resting and supine. All 5 MUGA studies were carried out after a single injection of Tc-99m labeled autologous red blood cells. The results show that the VDD mode brings about a higher left ventricular ejection fraction (LVEF) and cardiac output (CO) than the DVI mode, and that either of these dual-chamber pacing modes produces a higher LVEF and CO than single-chamber pacing (VVI). Furthermore, a longer A-V delay was shown to improve LVEF and CO in patients with initially low LVEF. The MUGA study is simple, noninvasive, objective, and quantifiable, and can easily be repeated several times following a single injection. It can be used to ''fine tune'' programmable pacemakers for optimum hemodynamic performance.

  15. New Approaches to Biological Pacemakers: Links to Sinoatrial Node Development.

    PubMed

    Vedantham, Vasanth

    2015-12-01

    Irreversible degeneration of the cardiac conduction system is a common disease that can cause activity intolerance, fainting, and death. While electronic pacemakers provide effective treatment, alternative approaches are needed when long-term indwelling hardware is undesirable. Biological pacemakers comprise electrically active cells that functionally integrate with the heart. Recent findings on cardiac pacemaker cells (PCs) within the sinoatrial node (SAN), along with developments in stem cell technology, have opened a new era in biological pacing. Recent experiments that have derived PC-like cells from non-PCs have brought the field closer than ever before to biological pacemakers that can faithfully recapitulate SAN activity. In this review, I discuss these approaches in the context of SAN biology and address the potential for clinical translation. PMID:26611337

  16. A patient with dizziness, tachycardia and a DDDR pacemaker

    PubMed Central

    Balt, J.C.; Dekker, P.; de Voogt, W.G.

    2006-01-01

    An 84-year-old female patient presented to the coronary care unit with dizziness. A DDD-R minute ventilation sensor pacemaker had been implanted eight years previously. The ECG showed an atrial and ventricular paced rhythm of 140 beats/min. After disconnecting the patient from the cardiac monitor the pacemaker rate dropped gradually to 90 beats/min. The cardiac rhythm monitoring system applies low-amplitude electrical pulses in order to measure respiration rate by transthoracic impedance (TTI) measurement. The minute ventilation pacemaker sensor is driven by the same TTI measurement for rate response. Inappropriate interference between these two systems caused a sensor-driven high pacemaker rate. The dizziness was not related to the sensor-driven high rate. ImagesFigure 1Figure 2 PMID:25696553

  17. MRI-conditional pacemakers: current perspectives.

    PubMed

    Ferreira, Antnio M; Costa, Francisco; Tralho, Antnio; Marques, Hugo; Cardim, Nuno; Adrago, Pedro

    2014-01-01

    Use of both magnetic resonance imaging (MRI) and pacing devices has undergone remarkable growth in recent years, and it is estimated that the majority of patients with pacemakers will need an MRI during their lifetime. These investigations will generally be denied due to the potentially dangerous interactions between cardiac devices and the magnetic fields and radio frequency energy used in MRI. Despite the increasing reports of uneventful scanning in selected patients with conventional pacemakers under close surveillance, MRI is still contraindicated in those circumstances and cannot be considered a routine procedure. These limitations prompted a series of modifications in generator and lead engineering, designed to minimize interactions that could compromise device function and patient safety. The resulting MRI-conditional pacemakers were first introduced in 2008 and the clinical experience gathered so far supports their safety in the MRI environment if certain conditions are fulfilled. With this technology, new questions and controversies arise regarding patient selection, clinical impact, and cost-effectiveness. In this review, we discuss the potential risks of MRI in patients with electronic cardiac devices and present updated information regarding the features of MRI-conditional pacemakers and the clinical experience with currently available models. Finally, we provide some guidance on how to scan patients who have these devices and discuss future directions in the field. PMID:24851058

  18. MRI-conditional pacemakers: current perspectives

    PubMed Central

    Ferreira, António M; Costa, Francisco; Tralhão, António; Marques, Hugo; Cardim, Nuno; Adragão, Pedro

    2014-01-01

    Use of both magnetic resonance imaging (MRI) and pacing devices has undergone remarkable growth in recent years, and it is estimated that the majority of patients with pacemakers will need an MRI during their lifetime. These investigations will generally be denied due to the potentially dangerous interactions between cardiac devices and the magnetic fields and radio frequency energy used in MRI. Despite the increasing reports of uneventful scanning in selected patients with conventional pacemakers under close surveillance, MRI is still contraindicated in those circumstances and cannot be considered a routine procedure. These limitations prompted a series of modifications in generator and lead engineering, designed to minimize interactions that could compromise device function and patient safety. The resulting MRI-conditional pacemakers were first introduced in 2008 and the clinical experience gathered so far supports their safety in the MRI environment if certain conditions are fulfilled. With this technology, new questions and controversies arise regarding patient selection, clinical impact, and cost-effectiveness. In this review, we discuss the potential risks of MRI in patients with electronic cardiac devices and present updated information regarding the features of MRI-conditional pacemakers and the clinical experience with currently available models. Finally, we provide some guidance on how to scan patients who have these devices and discuss future directions in the field. PMID:24851058

  19. Displacement of pacemaker leads--a 10-year survey.

    PubMed Central

    Brewster, G M; Evans, A L

    1979-01-01

    Displacement of endocardial pacemaker leads from the initial site at the time of implantation is a major cause of unpredictable pacemaker failure. In this survey, we have made a retrospective study of the effectiveness of the attempts made by two manufacturers to design leads to reduce the frequency of this occurrence. The cumulative displacement records of 5 types of leads (Medtronic types 5818, 6904, 6901, and 6950, and Cardiac Pacemakers Inc. type 4210) have been studied, and show that Medtronic 5818 and 6950, and CPI 4210 leads are superior in this respect. Images PMID:508447

  20. Reprogramming the conduction system: Onward toward a biological pacemaker.

    PubMed

    Meyers, Jason D; Jay, Patrick Y; Rentschler, Stacey

    2016-01-01

    Diseases of the cardiac conduction system can be debilitating and deadly. Electronic pacemakers are incredibly effective in the treatment of sinus and AV node dysfunction, yet there remain important limitations and complications. These issues have driven interest in the development of a biological pacemaker. Here, we review experimental progress in animal models and discuss future directions, with a focus on reprogramming endogenous cells in the heart to treat defects of rhythm and conduction. PMID:25937044

  1. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... coronary artery bypass surgery; (iii) Current stable angina pectoris; (iv) Heart valve repair or replacement; (v) Percutaneous transluminal coronary angioplasty (PTCA) or coronary stenting; (vi) A heart or heart-lung transplant. (vii) For cardiac rehabilitation only, other cardiac conditions as...

  2. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... coronary artery bypass surgery; (iii) Current stable angina pectoris; (iv) Heart valve repair or replacement; (v) Percutaneous transluminal coronary angioplasty (PTCA) or coronary stenting; (vi) A heart or heart-lung transplant. (vii) For cardiac rehabilitation only, other cardiac conditions as...

  3. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... coronary artery bypass surgery; (iii) Current stable angina pectoris; (iv) Heart valve repair or replacement; (v) Percutaneous transluminal coronary angioplasty (PTCA) or coronary stenting; (vi) A heart or heart-lung transplant. (vii) For cardiac rehabilitation only, other cardiac conditions as...

  4. Electromagnetic Interference on Pacemakers

    PubMed Central

    Erdogan, Okan

    2002-01-01

    External sources, either within or outside the hospital environment, may interfere with the appropriate function of pacemakers which are being implanted all around the world in current medical practice. The patient and the physician who is responsible for follow-up of the pacing systems may be confronted with some specific problems regarding the various types of electromagnetic interference (EMI). To avoid these unwanted EMI effects one must be aware of this potential problem and need to take some precautions. The effects of EMI on pacemaker function and precautions to overcome some specific problems were discussed in this review article. There are many sources of EMI interacting with pacemakers. Magnetic resonance imaging creates real problem and should be avoided in pacemaker patients. Cellular phones might be responsible for EMI when they were held on the same side with the pacemaker. Otherwise they don't cause any specific type of interaction with pacemakers. Sale security systems are not a problem if one walks through it without lingering in or near it. Patients having unipolar pacemaker systems are prone to develop EMI because of pectoral muscle artifacts during vigorous active physical exercise. PMID:17006562

  5. Sex differences in selection of pacemakers: retrospective observational study

    PubMed Central

    Schppel, Reinhart; Bchele, Gisela; Batz, Lothar; Koenig, Wolfgang

    1998-01-01

    Objective: To evaluate the effect of patients sex on selection of pacemakers. Design: Retrospective univariate and multivariate analysis of a large database. Setting: German central pacemaker register. Subjects: Records collected at the register for 1992 and 1993 (n=31?913), covering 64% of all implantations in Germany. Main outcome measure: Probability of receiving a single chamber, dual chamber, or rate responsive pacemaker in relation to sex. Results: Univariate analysis showed that women were more likely to receive single chamber pacemakers and less likely to receive dual chamber or rate responsive systems than men. After demographic and clinical variables were controlled for, women were still more likely to receive a single chamber system (atrial pacing: odds ratio 0.89, 95% confidence interval 0.74 to 1.07; ventricular pacing: 0.85, 0.80 to 0.92) and less likely to receive a dual chamber (1.20, 1.12 to 1.30) or a rate responsive system (1.26, 1.17 to 1.37) than men. Conclusions: The data suggest sex differences in the selection of a pacemaker system which cannot be explained by the underlying cardiac disorder. Further research is needed to evaluate why guidelines for implanting pacemakers are not better adhered to. Key messages Use of pacemakers varies despite guidelines, and the reasons for this are unclear In this study women were more likely to receive single chamber pacemakers and less likely to receive dual chamber and rate responsive pacemakers than men Demographic and clinical variables cannot fully explain these differences Prospective studies are needed to evaluate the effect of sex and other non-medical variables on the selection of pacemakers PMID:9582133

  6. Pacemaker lead endocarditis

    PubMed Central

    Scheffer, M.; van der Linden, E.; van Mechelen, R.

    2003-01-01

    We present a patient with a pacemaker lead endocarditis who showed no signs of pocket infection but with high fever and signs of infection in the routine laboratory tests. A diagnosis of pacemaker lead endocarditis must be considered in all patients with fever and infection parameters who have a pacemaker inserted, not only in the first weeks after implantation but also late after implantation, as long as no other cause of infection has been found. Transthoracal echocardiography alone is not sensitive enough to establish the correct diagnosis. Transoesophageal echocardiography (TEE) is mandatory to demonstrate the presence or absence of a vegetation on a pacemaker lead. ImagesFigure 1Figure 2Figure 3Figure 4 PMID:25696204

  7. Clinical assessment of pacemaker power sources

    SciTech Connect

    Bilitch, M.; Parsonnet, V.; Furman, S.

    1980-01-01

    The development of power sources for cardiac pacemakers has progressed from a 15-year usage of mercury-zinc batteries to widely used and accepted lithium cells. At present, there are about 6 different types of lithium cells incorporated into commercially distributed pacemakers. The authors reviewed experience over a 5-year period with 1711 mercury-zinc, 130 nuclear (P238) and 1912 lithium powered pacemakers. The lithium units have included 698 lithium-iodide, 270 lithium-silver chromate, 135 lithium-thionyl chloride, 31 lithium-lead and 353 lithium-cupric sulfide batteries. 57 of the lithium units have failed (91.2% component failure and 5.3% battery failure). 459 mercury-zinc units failed (25% component failure and 68% battery depletion). The data show that lithium powered pacemaker failures are primarily component, while mercury-zinc failures are primarily battery related. It is concluded that mercury-zinc powered pulse generators are obsolete and that lithium and nuclear (P238) power sources are highly reliable over the 5 years for which data are available. 3 refs.

  8. Triboelectric simulation of pacemaker malfunction.

    PubMed

    Kahan, S; Miller, C W; Hayes, D L; Barold, S S

    2002-07-01

    We report the occurrence of a triboelectric phenomenon (static electricity) that mimicked malfunction of a contemporary pacemaker by creating an electrocardiograpic artifact virtually identical to the pacemaker stimuli. The diagnosis was established by observing a subtle overshoot of the questionable deflection that was absent from pacemaker stimuli. PMID:12134980

  9. Not all pacemakers are created equal: MRI conditional pacemaker and lead technology.

    PubMed

    Ahmed, Fozia Z; Morris, Gwilym M; Allen, Stuart; Khattar, Rajdeep; Mamas, Mamas; Zaidi, Amir

    2013-09-01

    Due to expanding clinical indications and an aging society there has been an increase in the use of implantable pacemakers. At the same time, due to increased diagnostic yield over other imaging modalities and the absence of ionizing radiation, there has been a surge in demand for magnetic resonance imaging (MRI) assessment, of both cardiac and noncardiac conditions. Patients with an implantable device have a 50-75% chance of having a clinical indication for MRI during the lifetime of their device. The presence of an implantable cardiac device has been seen as a relative contraindication to MRI assessment, limiting the prognostic and diagnostic utility of MRI in many patients with these devices. The introduction of MRI conditional pacemakers will enable more patients to undergo routine MRI assessment without risk of morbidity or device malfunction. This review gives a general overview of the principles and current evidence for the use of MRI conditional implantable cardiac devices. Furthermore, we appraise the differences between those pacemakers currently released to market. PMID:24016320

  10. The experiences of patients undertaking a 'virtual' cardiac rehabilitation program.

    PubMed

    Banner, Davina; Lear, Scott; Kandola, Daman; Singer, Joel; Horvat, Dan; Bates, Joanna; Ignaszewski, Andrew

    2015-01-01

    Cardiac rehabilitation programs (CRP) are medically supervised, multidisciplinary programs that provide secondary prevention aimed at addressing risk factors and improving lifestyle behaviours for patients following an acute cardiac event. CRPs have been demonstrated to be a cost-effective and evidence-based mechanism to improve patient outcomes, but despite the known benefits of these programs, uptake remains poor. Poor attendance has been linked to many factors, but geographical accessibility is a key concern, since many CRPs are limited to hospitals in urban areas. The widespread availability of the Internet has made it possible to provide virtual health services to populations that may have previously been hard to access. This paper examines the qualitative findings from a 16-month mixed methods randomized controlled trial examining the impact of a virtual CRP (vCRP). The vCRP was revealed to be an accessible, appropriate, convenient and effective way to deliver cardiac rehabilitation services, with patients experiencing both clinical improvements and a high level of satisfaction. To understand the experience of patients undertaking the vCRP, semi-structured interviews were undertaken with a purposive sample of 22 participants. An analysis of the qualitative interviews revealed that the vCRP improved participants' access to healthcare professionals, supported them to make healthy choices, and enhanced feelings of accountability due to greater surveillance. Barriers to participation, such as computer literacy, and general perceptions of a vCRP were also examined. Further investigation into the use and long-term effectiveness of virtual programs across a broader range of healthcare settings is warranted, particularly in those with multiple chronic diseases and those located in rural and remote communities. PMID:25980699

  11. [Progress in cardiac pacing].

    PubMed

    Sancho-Tello de Carranza, Mara-Jos; Ruiz-Mateas, Francisco; Fidalgo-Andrs, Mara Luisa; Buenda-Fuentes, Francisco

    2011-01-01

    This article contains a discussion of the most recent developments in cardiac resynchronization therapy, of the feasibility of performing magnetic resonance imaging in patients with cardiac pacemakers, and of the current and future status of leadless pacing. Finally, the most significant scientific articles published in the last year are reviewed. PMID:21276495

  12. Permanent internal pacemaker safety in air medical transport.

    PubMed

    Gordon, R S; O'Dell, K B

    1991-02-01

    Helicopter and fixed-wing air medical transportation provides an important role in the management of critically-ill patients. As the use of cardiac pacemakers continues to grow, knowledge of their expanding capabilities and sophistication is important. The environments of our "airborne intensive care units" are subject to many sources of electromagnetic and vibrational interference. Although pacemaker shielding mechanisms have become quite elaborate, further studies are needed to define their reliability in modern aircraft. Further, the possible effects of electromagnetic and vibrational interference upon inflight reprogramming require further study. PMID:10109075

  13. Reuse Of Pacemakers In Ghana And Nigeria: Medical, Legal, Cultural And Ethical Perspectives.

    PubMed

    Ochasi, Aloysius; Clark, Peter

    2015-12-01

    According to the World Health Organization (WHO) cardiovascular disease (CVD) is the leading cause of death globally. Over 80% of CVD deaths take place in low- and middle-income countries (LMICs). It is estimated that 1 million to 2 million people worldwide die each year due to lack of access to an implantable cardiac defibrillator (ICD) or a pacemaker. Despite the medical, legal, cultural and ethical controversies surrounding the pacemaker reutilization, studies done so far on the reuse of postmortem pacemakers show it to be safe and effective with an infection rate of 1.97% and device malfunction rate of 0.68%. Pacemaker reutilization can be effectively and safely done and does not pose significant additional risk to the recipient. Heart patients with reused pacemakers have an improved quality of life compared to those without pacemakers. The thesis of this paper is that pacemaker reutilization is a life-saving initiative in LMICs of Nigeria and Ghana. It is cost effective; consistent with the principles of beneficence, nonmaleficence, and justice with a commitment to stewardship of resources and the Common Good. Used pacemakers with adequate battery life can be properly sterilized for use by patients in LMICs who cannot afford the cost of a new pacemaker. PMID:24720369

  14. What Are the Risks of Pacemaker Surgery?

    MedlinePLUS

    ... NHLBI on Twitter. What Are the Risks of Pacemaker Surgery? Pacemaker surgery generally is safe. If problems do occur, ... bruising, or infection in the area where the pacemaker was placed Blood vessel or nerve damage A ...

  15. In utero Undernutrition Programs Skeletal and Cardiac Muscle Metabolism

    PubMed Central

    Beauchamp, Brittany; Harper, Mary-Ellen

    2016-01-01

    In utero undernutrition is associated with increased risk for insulin resistance, obesity, and cardiovascular disease during adult life. A common phenotype associated with low birth weight is reduced skeletal muscle mass. Given the central role of skeletal muscle in whole body metabolism, alterations in its mass as well as its metabolic characteristics may contribute to disease risk. This review highlights the metabolic alterations in cardiac and skeletal muscle associated with in utero undernutrition and low birth weight. These tissues have high metabolic demands and are known to be sites of major metabolic dysfunction in obesity, type 2 diabetes, and cardiovascular disease. Recent research demonstrates that mitochondrial energetics are decreased in skeletal and cardiac muscles of adult offspring from undernourished mothers. These effects apparently lead to the development of a thrifty phenotype, which may represent overall a compensatory mechanism programmed in utero to handle times of limited nutrient availability. However, in an environment characterized by food abundance, the effects are maladaptive and increase adulthood risks of metabolic disease. PMID:26779032

  16. Effect of cardiac resynchronization therapy with implantable cardioverter defibrillator versus cardiac resynchronization therapy with pacemaker on mortality in heart failure patients: results of a high-volume, single-centre experience

    PubMed Central

    Kutyifa, Valentina; Geller, Laszlo; Bogyi, Peter; Zima, Endre; Aktas, Mehmet K; Ozcan, Emin Evren; Becker, David; Nagy, Vivien Klaudia; Kosztin, Annamaria; Szilagyi, Szabolcs; Merkely, Bela

    2014-01-01

    Aims There are limited and contradictory data on the effects of CRT with implantable cardioverter defibrillator (CRT-D) on mortality as compared with CRT with pacemaker (CRT-P). Methods and results We evaluated the long-term outcome of patients implanted with a CRT-D or CRT-P device in our high-volume single-centre experience. Data on all-cause mortality were derived from clinic visits and the Hungarian National Healthcare Fund Death Registry. KaplanMeier survival analyses and multivariate Cox regression models were used to evaluate all-cause mortality in patients with CRT-D vs. CRT-P, stratified by the aetiology of cardiomyopathy. From 2000 to 2011, 1122 CRT devices, 693 CRT-P (LVEF 28.2??7.4%) and 429 CRT-D (LVEF 27.6??6.4%), were implanted at our centre. During the median follow-up of 28 months, 379 patients died from any cause, 250 patients (36%) with an implanted CRT-P and 129 patients (30%) with an implanted CRT-D. There was no evidence of mortality benefit in patients implanted with a CRT-D compared with a CRT-P in the total cohort [hazard ratio (HR) 0.98, 95% confidence interval (CI) 0.731.32, P?=?0.884]. In patients with ischaemic cardiomyopathy, CRT-D treatment was associated with a significant 30% risk reduction in all-cause mortality compared with an implanted CRT-P (HR 0.70, 95% CI 0.510.97, P?=?0.03). In non-ischaemic patients, there was no mortality benefit of CRT-D over CRT-P (HR 0.98, 95% CI 0.731.32, P?=?0.894, interaction P-value?=?0.15). Conclusions In heart failure patients with ischaemic cardiomyopathy, CRT-D was associated with a mortality benefit compared with CRT-P, but no benefit of CRT-D over CRT-P in mortality was observed in non-ischaemic cardiomyopathy. PMID:25379962

  17. Pacemaker Created in Human Ventricle by Depressing Inward-Rectifier K+ Current: A Simulation Study

    PubMed Central

    Zhang, Yue; Li, Qince; Zhang, Henggui

    2016-01-01

    Cardiac conduction disorders are common diseases which cause slow heart rate and syncope. The best way to treat these diseases by now is to implant electronic pacemakers, which, yet, have many disadvantages, such as the limited battery life and infection. Biopacemaker has been expected to replace the electronic devices. Automatic ventricular myocytes (VMs) could show pacemaker activity, which was induced by depressing inward-rectifier K+ current (IK1). In this study, a 2D model of human biopacemaker was created from the ventricular endocardial myocytes. We examined the stability of the created biopacemaker and investigated its driving capability by finding the suitable size and spatial distribution of the pacemaker for robust pacing and driving the surrounding quiescent cardiomyocytes. Our results suggest that the rhythm of the pacemaker is similar to that of the single cell at final stable state. The driving force of the biopacemaker is closely related to the pattern of spatial distribution of the pacemaker. PMID:26998484

  18. Stem Cell Based Biological Pacemakers From Proof of Principle to Therapy: a Review

    PubMed Central

    Chauveau, Samuel; Brink, Peter R.; Cohen, Ira S.

    2014-01-01

    Electronic pacemakers are the standard therapy for bradycardia related symptoms but have shortcomings. Over the past 15 years experimental evidence has demonstrated that gene and cell-based therapies can create a biological pacemaker. Recently, physiologically acceptable rates have been reported with an adenovirus-based approach. But adenovirus-based protein expression does not last more than 4 weeks, which limits its clinical applicability. Cell-based platforms are potential candidates for longer expression. Currently there are two cell based approaches being tested: 1) Mesenchymal stem cells used as a suitcase for delivering pacemaker genes and 2) Pluripotent stem cells differentiated down a cardiac lineage with endogenous pacemaker activity. This review examines the current achievements in engineering a biological pacemaker, defines the patient population for whom this device would be useful and identifies the challenges still ahead before cell therapy can replace current electronic devices. PMID:24831844

  19. [Microwave ablation of a sarcoma lung metastasis in a patient with a pacemaker].

    PubMed

    Hidalgo, A; Guerra, J M; Gallego, O; Franquet, T

    2014-01-01

    We present the case of a patient with a pacemaker and a sarcoma lung metastasis treated with microwave ablation. Although the treatment of tumours with microwave ablation is a successful and minimally invasive approach, there are concerns about the safety of this procedure for patients with implanted cardiac devices, such as a pacemaker. After careful planning between radiology and cardiology, microwave ablation was indicated in the patient since it is safer and shorter than the radiofrequency technique. The lesion was treated without complications. It is important to communicate the procedures performed, as well as any complications in order to formulate guidelines for the use of microwave ablation in patients with pacemakers. PMID:21944709

  20. In vitro investigation of eddy current effect on pacemaker operation generated by low frequency magnetic field.

    PubMed

    Babouri, A; Hedjeidj, A

    2007-01-01

    This paper presents in vitro investigation of the eddy current induction effects to the cardiac pacemaker exposed to low frequency magnetic fields. The method used in this study is based to the interaction by inductive coupling through the loop formed by the pacemaker and its leads and the surrounding medium. This interaction results in an induced electromotive force between the terminals of the pacemaker which can potentially disturb the operation of this last. In this article we present experimental results, analytical calculations and numerical simulations using the finite element method. PMID:18003302

  1. Evaluation of a New Cardiac Pacemaker

    ClinicalTrials.gov

    2013-06-25

    Atrial Fibrillation With 2 or 3° AV or Bifascicular Bundle Branch (BBB) Block; Normal Sinus Rhythm With 2 or 3° AV or BBB Block; Sinus Bradycardia With Infrequent Pauses or Unexplained Syncope With EP Findings

  2. Defibrillator/monitor/pacemakers.

    PubMed

    1998-02-01

    This study updates our May-June 1993 Evaluation of defibrillator/monitor/pacemakers, published in Health Devices 22(5-6), in which we tested eight units from six suppliers. For this Update Evaluation, we tested three additional units, each from a different supplier. We also present update information, including some new ratings, for most of the previously evaluated units. We judged the new units against the same basic criteria and rated and ranked them using the same scheme--with some minor revisions--as in our original Evaluation. We judged the suitability of these units for three primary clinical applications: (1) general crash-cart use, (2) prehospital (emergency medical service [EMS]) use, and (3) in-hospital transport use. Because our criteria have changed slightly since the original study, we have repeated them in this issue. The test methods have not changed significantly and can be found in the original 1993 Evaluation. For more detailed information about this technology, the environments in which these units are used, and the factors to consider when selecting this type of device, we encourage readers to refer to the following sections in the original Evaluation: the Clinical Perspective "The Importance of Early Defibrillation"; the Clinical and Technical Overview; and the Selection and Use Guide for Defibrillator/Monitor/Pacemakers. PMID:9498129

  3. An unusual cause of pacemaker-induced severe tricuspid regurgitation.

    PubMed

    Loupy, A; Messika-Zeitoun, D; Cachier, A; Himbert, D; Brochet, E; Lung, B; Vahanian, A

    2008-01-01

    Pacemaker (PM) induced tricuspid regurgitation (TR) is a common echocardiographic finding. Although mild or moderate TR is frequently observed, severe TR is rare. We report the exceptional observation of a severe TR due to leaflet malcoaptation occurring late after PM implantation and in the following weeks after an aortic valve replacement. Our hypothesis is that the aortic valve surgery has been responsible for conformational changes between cardiac cavities, tricuspid valve and PM leads resulting in a severe TR. PMID:18267925

  4. How sweet is the pacemaker?

    PubMed

    Merinopoulos, I; O'Toole, S; Porter, J N; Braganza, D; Mistry, C; Vassiliou, V; Enoch, D A

    2014-01-01

    Pacemaker infections can be difficult to diagnose, especially when they present with non-specific symptoms and signs a long time after insertion of the device. Unidentified or partially treated low-grade chronic sepsis can result in multisystem disease processes with significant mortality and morbidity. Therefore, a high index of suspicion is required to identify the pacemaker as the source of sepsis and treat it effectively. This report describes a case of chronic pacemaker wire infection, which eventually presented with Sweet's syndrome, a rare manifestation of infective endocarditis. PMID:25318396

  5. 1978 Pacemaker Newspaper Awards: What Makes a Pacemaker?

    ERIC Educational Resources Information Center

    Brasler, Wayne

    1979-01-01

    Lists the nine high school and college newspapers, and the one newsmagazine, that won Pacemaker Awards in 1978; discusses characteristics that make each of them outstanding, and provides reproductions of a front page from each publication. (GT)

  6. Prevalence of E/A Wave Fusion and A Wave Truncation in DDD Pacemaker Patients with Complete AV Block under Nominal AV Intervals

    PubMed Central

    Poller, Wolfram C.; Dreger, Henryk; Schwerg, Marius; Melzer, Christoph

    2015-01-01

    Aims Optimization of the AV-interval (AVI) in DDD pacemakers improves cardiac hemodynamics and reduces pacemaker syndromes. Manual optimization is typically not performed in clinical routine. In the present study we analyze the prevalence of E/A wave fusion and A wave truncation under resting conditions in 160 patients with complete AV block (AVB) under the pre-programmed AVI. We manually optimized sub-optimal AVI. Methods We analyzed 160 pacemaker patients with complete AVB, both in sinus rhythm (AV-sense; n = 129) and under atrial pacing (AV-pace; n = 31). Using Doppler analyses of the transmitral inflow we classified the nominal AVI as: a) normal, b) too long (E/A wave fusion) or c) too short (A wave truncation). In patients with a sub-optimal AVI, we performed manual optimization according to the recommendations of the American Society of Echocardiography. Results All AVB patients with atrial pacing exhibited a normal transmitral inflow under the nominal AV-pace intervals (100%). In contrast, 25 AVB patients in sinus rhythm showed E/A wave fusion under the pre-programmed AV-sense intervals (19.4%; 95% confidence interval (CI): 12.626.2%). A wave truncations were not observed in any patient. All patients with a complete E/A wave fusion achieved a normal transmitral inflow after AV-sense interval reduction (mean optimized AVI: 79.4 13.6 ms). Conclusions Given the rate of 19.4% (CI 12.626.2%) of patients with a too long nominal AV-sense interval, automatic algorithms may prove useful in improving cardiac hemodynamics, especially in the subgroup of atrially triggered pacemaker patients with AV node diseases. PMID:25707003

  7. Formal Specification of a Cardiac Pacing System

    NASA Astrophysics Data System (ADS)

    Gomes, Artur Oliveira; Oliveira, Marcel Vincius Medeiros

    The International Grand Challenge project on Verified Software is a long-term research program involving people from all over the world and is aimed to stimulate the creation of new theories and tools to be applied on industrial-scale problems. One of the challenges proposed is to make a formal development of a cardiac pacemaker. In this paper, we present a formal specification of this system using the Z notation and also discuss our experience in building this formal model and the decisions made during the process.

  8. Cardiac Resynchronization Therapy and phase resetting of the sinoatrial node: A conjecture

    NASA Astrophysics Data System (ADS)

    Cantini, Federico; Varanini, Maurizio; Macerata, Alberto; Piacenti, Marcello; Morales, Maria-Aurora; Balocchi, Rita

    2007-03-01

    Congestive heart failure is a severe chronic disease often associated with disorders that alter the mechanisms of excitation-contraction coupling that may result in an asynchronous left ventricular motion which may further impair the ability of the failing heart to eject blood. In recent years a therapeutic approach to resynchronize the ventricles (cardiac resynchronization therapy, CRT) has been performed through the use of a pacemaker device able to provide atrial-based biventricular stimulation. Atrial lead senses the spontaneous occurrence of cells depolarization and sends the information to the generator which, in turn, after a settled delay [atrioventricular (AV) delay], sends electrical impulses to both ventricles to stimulate their synchronous contraction. Recent studies performed on heart rate behavior of chronically implanted patients at different epochs after implantation have shown that CRT can lead to sustained overall improvement of heart function with a reduction in morbidity and mortality. At this moment, however, there are no studies about CRT effects on spontaneous heart activity of chronically implanted patients. We performed an experimental study in which the electrocardiographic signal of five subjects under chronic CRT was recorded during the activity of the pacemaker programmed at different AV delays and under spontaneous cardiac activity after pacemaker deactivation. The different behavior of heart rate variability during pacemaker activity and after pacemaker deactivation suggested the hypothesis of a phase resetting mechanism induced by the pacemaker stimulus on the sinoatrial (SA) node, a phenomenon already known in literature for aggregate of cardiac cells, but still unexplored in vivo. The constraints imposed by the nature of our study (in vivo tests) made it impossible to plan an experiment to prove our hypothesis directly. We therefore considered the best attainable result would be to prove the accordance of our data to the conjecture through the use of models and physical considerations. We first used the data of literature on far-field effects of cardiac defibrillators to prove that the pacemaker impulses delivered to the two ventricles were able to induce modifications in membrane voltage at the level of the SA node. To simulate a phase resetting mechanism of the SA node, we used a Van der Pol modified model to allow the possibility of changing the refractory period and the firing frequency of the cells separately. With appropriate parameters of the model we reproduced phase response curves that can account for our experimental data. Furthermore, the simulated curves closely resemble the functional form proposed in literature for perturbed aggregate of cardiac cells. Despite the small sample of subjects investigated and the limited number of ECG recordings at different AV delays, we think we have proved the plausibility of the proposed conjecture.

  9. A pacemaker cell pair model based on the phase response curve.

    PubMed

    Abramovich-Sivan, S; Akselrod, S

    1998-07-01

    A pacemaker cell pair model and the dynamic interaction between the two pacemaker cells is described in this paper. It is an extension of our single pacemaker cell model, in which we studied its response to repetitive external depolarization stimulations. This model is a simple model based on the two most important functional properties of the cardiac pacemaker cells: its intrinsic pacemaker cycle length, which is an 'internal' parameter of the cell, and the phase response curve (PRC), which is an 'overall collective' function. The PRC contains all the 'information' about the possible interactions of the pacemaker cell with the outside world (interaction with surrounding cells, external stimulus, etc.). First, we examined the properties and solutions of 1:1 synchronization between two pacemaker cells. We found that in order to achieve synchronization between two pacemaker cells, there should be limitations on the PRC parameters, which depend on the cells intrinsic cycle lengths. Next, we investigated the 2:1 entrainment state between two interacting pacemaker cells. We found that there is not necessarily a unique solution for this state as there was for the 1:1 state. Finally, we ran our computer model to investigate the properties of more complex patterns of entrainment between two pacemaker cells. As a result of our analytical study, we unveil two new important parameters, which are fully defined as a function of the PRC parameters: (1) the 'accelerator factor' which describes the tendency of a pair of interacting pacemaker cells to synchronize at a common cycle length, which is closer to the faster cycle of the pair; (2) the 'degree of coupling', which describes the range of the 1:1 synchronization and the 'strength' of the interaction between a pair of interacting pacemaker cells. Those two interaction parameters arise as helpful 'tools' for the understanding of synchronization and mutual entrainment mechanisms between pacemaker cells. Therefore, this study establishes the PRC as an important determinant and a useful approach for the understanding of the dynamic interaction of pacemaker cells among themselves and with the outside world. PMID:9742680

  10. Pacemaker limitation of tachycardia in hypovolemic shock.

    PubMed

    Sparacino, Nicholas; Geninatti, Marilyn; Moore, Gregory

    2011-11-01

    A 49-year-old white man was admitted to the emergency department with nausea and diarrhea of 11 hours duration. He had experienced crampy abdominal pain as well. He reported that his stools had been dark and malodorous. He had no prior history of gastrointestinal disorders, nor travel, unusual oral or liquid intake. There was a remote history of alcohol abuse, but no hepatitis or cirrhosis. Recent alcohol intake was denied by the patient. He had no medical allergies. His past medical history was pertinent for a history of hypertension, congestive heart failure, and a dual chamber pacemaker insertion. There was no history of diabetes mellitus, smoking, or myocardial infarction. Medications included lisinopril, a small dose of aspirin daily, and thyroid supplement. Family history was negative for cardiomyopathy, sudden cardiac death, gastric or duodenal ulcers, colon cancer, or any congenital abnormalities. PMID:22224162

  11. The effects of extracorporeal shock wave lithotripsy on pacemaker function.

    PubMed

    Langberg, J; Abber, J; Thuroff, J W; Griffin, J C

    1987-09-01

    Twenty-two pacemaker pulse generators were exposed to shock waves of an extracorporeal shock wave lithotripter to assess the effects of the extremely high pressure transients on pacemaker function. The pulse generator and distal aspect of the lead were positioned 5 cm from the focal point of the lithotripter and 10 cm from each other. Pulse generator function was analyzed during shock wave delivery synchronized with pulse generator output, during shock waves at a rate faster than the escape rate, and after exposure to lithotripsy. During shock waves delivered synchronously with pulse generator output, only one of 22 pulse generators malfunctioned by intermittently reverting to the magnet rate. When subjected to shock waves at a rate greater than the escape rate, 50% of the pulse generators were inhibited by electromechanical interference from the lithotripter. Both bipolar and unipolar devices were affected. However, analysis after exposure to shock waves showed that none of the pacemakers was damaged or spuriously reprogrammed. In conclusion, cardiac pacemakers do not appear to be damaged or reprogrammed by exposure to extracorporeal shock wave lithotripsy. The likelihood of false inhibition appears to be very low if shock waves are delivered synchronously with the QRS. PMID:2444938

  12. Cardiac catheterization and angiography. Third edition

    SciTech Connect

    Grossman, W.

    1986-01-01

    This book discusses the papers on cardiac catheterization and angiography. The topics covered are: historical perspective and present practice of cardiac catheterization; angiography principles and utilization of radiologic and cineangiographic equipment; complications, incidence and prevention of side effects of cardiac catheterization; techniques; blood flow measurement of heart; pressure measurement; diagnostic techniques of angiography; special catheter techniques; coronary angiography, temporary and permanent pacemakers, potential role of lasers in the cardiac catheterization and evaluation of cardiac function.

  13. Current facts on pacemaker electromagnetic interference and their application to clinical care

    SciTech Connect

    Sager, D.P.

    1987-03-01

    The development of the sensing demand cardiac pacemaker brought with it the problem of interference as a result of extraneous electric current and electromagnetic fields. This problem still deserves consideration, not only because harmful disruption of pacemaker function, while infrequent, can occur but also because myths and misunderstandings have flourished on the subject. Misinformation has often led to needless patient anxiety and unnecessary restrictions in activities of daily living. Similarly, when health care practitioners are misinformed about pacemaker interference, potentially hazardous situations can occur in the clinical environment. This article is a review of current information on the sources and effects of electromagnetic interference (EMI) on pacemakers and includes a discussion of their application to patient care.

  14. Magnetic Resonance Imaging in a Patient with a Dual Chamber Pacemaker

    PubMed Central

    Millar, Lynne Martina; Robinson, Andrew George; O'Flaherty, Maurice Thomas; Eames, Niall; Johnston, Nicola; Heyburn, Gary

    2010-01-01

    Having a pacemaker has been seen an absolute contraindication to having an MRI scan. This has become increasingly difficult in clinical practice as insertion of pacemakers and implantable cardiac defibrillators is at an all time high. Here we outline a case where a 71-year-old male patient with a permanent pacemaker needed to have an MRI scan to ascertain the aetiology of his condition and help guide further management. Given this clinical dilemma, an emergency clinical ethics consultation was arranged. As a result the patient underwent an MRI scan safely under controlled conditions with a consultant cardiologist and radiologist present. The results of the MRI scan were then able to tailor further treatment. This case highlights that in certain conditions an MRI can be performed in patients with permanent pacemakers and outlines the role of clinical ethics committees in complex medical decision making. PMID:21331383

  15. AACVPR consensus statement. Outcomes evaluation in cardiac rehabilitation/secondary prevention programs: improving patient care and program effectiveness.

    PubMed

    Sanderson, Bonnie K; Southard, Douglas; Oldridge, Neil

    2004-01-01

    The reported outcomes statement is an update to the previous recommendations for outcomes evaluation in cardiac rehabilitation/secondary prevention programs. The purposes of outcomes evaluation are reviewed, and practical information with examples is provided to help programs implement an outcomes-directed approach within routine patient care and program management functions. PMID:15052108

  16. [Progress in cardiac pacing].

    PubMed

    Sancho-Tello de Carranza, Mara-Jos; Martnez-Ferrer, Jos; Pombo-Jimnez, Marta; de Juan-Montiel, Jess

    2010-01-01

    This review discusses the utility and current status of remote monitoring in patients with cardiac devices in Spain, the different anticoagulation strategies used during device implantation, the surgical replacement and maintenance of pacemakers and defibrillators, and the present and future importance of impedance sensors in cardiac pacing and heart failure management. Finally, there is a summary of the most relevant scientific articles published in the last year. PMID:20223181

  17. Ventricular pacing on the prognosis of patients with pacemaker implantation.

    PubMed

    Zheng, Liuying; Du, Xinping

    2014-06-01

    Excessive right ventricular apex pacing has significant adverse effects on the cardiac function and hence, it is necessary to clinically optimize pacing parameters and advocate suitable physiological pacing to safeguard the cardiac function after pacemaker implant. Minimizing ventricular pacing is an atrioventricular node priority function, to encourage ventricular self conduction and to reduce unnecessary right ventricular pacing. Minimized ventricular pacing reduces ventricular pacing by encouraging self atrioventricular conduction function and extending the AV interval. This study is a prospective cohort study to evaluate the changes of cardiac function in patients and serum amino-terminal natriuretic peptide (NT-proBNP) before and after pacing, and the risk of atrial fibrillation with different CUM% VP. The study has shown that the cardiac function will deteriorate with an increase in pacing rate. PMID:24242189

  18. Transfer of the heart pacemaker during juvenile development in the isopod crustacean Ligia exotica.

    PubMed

    Yamagishi, H; Hirose, E

    1997-09-01

    Developmental changes in heartbeat pacemaker mechanisms were examined electrophysiologically in the isopod crustacean Ligia exotica. The heartbeat of embryos and early juveniles was myogenic. The heart muscle cells were coupled electrically, and no localized pacemaker activity was found in the heart. In newly hatched juveniles, the cardiac ganglion exhibited no spontaneous activity, although stimulation of the cardiac ganglion produced excitatory junctional potentials (EJPs) in the heart muscle. The myogenic activity of the heart was reset and entrained by the EJPs evoked by ganglionic stimulation. During juvenile development, spontaneous EJPs appeared irregularly in the heart muscle. Later in development, the cardiac ganglion started rhythmic bursting, and each muscle response followed a ganglionic burst discharge and overlapped the EJPs evoked by ganglionic activity. At this point, the activity of the cardiac ganglion was suppressed by application of tetrodotoxin (TTX); however, even in old adults, both muscle activity and the heartbeat continued following TTX application. Heartbeat frequency was lower in TTX-containing saline than in normal saline. These results show that, during juvenile development, the heart pacemaker is transferred from the heart muscle to the cardiac ganglion, which becomes the primary pacemaker and entrains the heart muscle activity to a higher frequency via EJPs. PMID:9343853

  19. Service and business model for technology enabled and home-based cardiac rehabilitation programs.

    PubMed

    Sarela, Antti; Whittaker, Frank; Korhonen, Ilkka

    2009-01-01

    Cardiac rehabilitation programs are comprehensive life-style programs aimed at preventing recurrence of a cardiac event. However, the current programs have globally significantly low levels of uptake. Home-based model can be a viable alternative to hospital-based programs. We developed and analysed a service and business model for home based cardiac rehabilitation based on personal mentoring using mobile phones and web services. We analysed the different organizational and economical aspects of setting up and running the home based program and propose a potential business model for a sustainable and viable service. The model can be extended to management of other chronic conditions to enable transition from hospital and care centre based treatments to sustainable home-based care. PMID:19964213

  20. Defibrillator/monitor/pacemakers.

    PubMed

    2000-09-01

    Defibrillator/monitors allow operators to assess and monitor a patient's ECG and, when necessary, deliver a defibrillating shock to the heart. When integral noninvasive pacing capability is added, the resulting device is referred to as a defibrillator/monitor/pacemaker. In this Update Evaluation, we present our findings for nine such units, including complete Product Profiles for two newly evaluated models and update information for seven other models evaluated in our May-June 1993 and February 1998 studies. We tested the two newly evaluated models using the same basic protocol as in our previous studies. However, we did add some new tests--and revise some old ones--to account for advances in the technology. These advancements include the increasing use of advisory modes and the increasing availability of expanded monitoring capabilities (which allow units to function, at least to some degree, like a physiologic monitor). As in our previous studies, we rated each model separately for three common defibrillation applications: (1) general crashcart use, (2) in-hospital transport use, and (3) prehospital use by emergency medical services (EMS) personnel. Because each application requires its own set of capabilities, it's not surprising that few models are appropriate for all applications. However, we did identify three models that perform well--earning a rating of either Acceptable or Preferred--in all three areas. PMID:11022316

  1. Clinical experience with nuclear pacemakers.

    PubMed

    Parsonnet, V; Myers, G H; Gilbert, L; Zucker, I R

    1975-12-01

    Approximately 1,400 nuclear pacemakers have been implanted in patients since April, 1970, without a single battery failure; 64 of these have been implanted at the Newark Beth Israel Medical Center. All except four of the 64 pulse generators were attached to transvenous electrodes, 39 to pacing wires already in place. Fifty-nine of the 64 units are in service and continue to function normally in a follow-up period of up to 2 years. In the total worldwide experience, 70 pacemakers are out of service, approximately half because of the patient's death, and the rest for infection or lead problems, and only three or four because of difficulties with components. The first 15 ARCO pacemakers implanted 2 years ago continue to function well. Of the 15 control pacemakers implanted at the same time, one unit has failed. We have concluded that a nuclear pacemaker should not be used in a patient with limited life expectancy or in an infant, but for the otherwise healthy young or middle-age individual, it should be the unit of choice. PMID:1188620

  2. Forward Programming of Cardiac Stem Cells by Homogeneous Transduction with MYOCD plus TBX5

    PubMed Central

    Belian, Elisa; Noseda, Michela; Abreu Paiva, Marta S.; Leja, Thomas; Sampson, Robert; Schneider, Michael D.

    2015-01-01

    Adult cardiac stem cells (CSCs) express many endogenous cardiogenic transcription factors including members of the Gata, Hand, Mef2, and T-box family. Unlike its DNA-binding targets, Myocardin (Myocd)—a co-activator not only for serum response factor, but also for Gata4 and Tbx5—is not expressed in CSCs. We hypothesised that its absence was a limiting factor for reprogramming. Here, we sought to investigate the susceptibility of adult mouse Sca1+ side population CSCs to reprogramming by supplementing the triad of GATA4, MEF2C, and TBX5 (GMT), and more specifically by testing the effect of the missing co-activator, Myocd. Exogenous factors were expressed via doxycycline-inducible lentiviral vectors in various combinations. High throughput quantitative RT-PCR was used to test expression of 29 cardiac lineage markers two weeks post-induction. GMT induced more than half the analysed cardiac transcripts. However, no protein was detected for the induced sarcomeric genes Actc1, Myh6, and Myl2. Adding MYOCD to GMT affected only slightly the breadth and level of gene induction, but, importantly, triggered expression of all three proteins examined (α-cardiac actin, atrial natriuretic peptide, sarcomeric myosin heavy chains). MYOCD + TBX was the most effective pairwise combination in this system. In clonal derivatives homogenously expressing MYOCD + TBX at high levels, 93% of cardiac transcripts were up-regulated and all five proteins tested were visualized. In summary: (1) GMT induced cardiac genes in CSCs, but not cardiac proteins under the conditions used. (2) Complementing GMT with MYOCD induced cardiac protein expression, indicating a more complete cardiac differentiation program. (3) Homogeneous transduction with MYOCD + TBX5 facilitated the identification of differentiating cells and the validation of this combinatorial reprogramming strategy. Together, these results highlight the pivotal importance of MYOCD in driving CSCs toward a cardiac muscle fate. PMID:26047103

  3. Cardiac arrhythmias during exercise testing in healthy men.

    NASA Technical Reports Server (NTRS)

    Beard, E. F.; Owen, C. A.

    1973-01-01

    Clinically healthy male executives who participate in a long-term physical conditioning program have demonstrated cardiac arrhythmia during and after periodic ergometric testing at submaximal and maximal levels. In 1,385 tests on 248 subjects, it was found that 34% of subjects demonstrated an arrhythmia at some time and 13% of subjects developed arrhythmia on more than one test. Premature systoles of ventricular origin were most common, but premature systoles of atrial origin, premature systoles of junctional origin, paroxysmal atrial tachycardia, atrioventricular block, wandering pacemaker, and pre-excitation were also seen. Careful post-test monitoring and pulse rate regulated training sessions are suggested for such programs.

  4. Cardiac risk stratification in cardiac rehabilitation programs: a review of protocols

    PubMed Central

    da Silva, Anne Kastelianne França; Barbosa, Marianne Penachini da Costa de Rezende; Bernardo, Aline Fernanda Barbosa; Vanderlei, Franciele Marques; Pacagnelli, Francis Lopes; Vanderlei, Luiz Carlos Marques

    2014-01-01

    Objective Gather and describe general characteristics of different protocols of risk stratification for cardiac patients undergoing exercise. Methods We conducted searches in LILACS, IBECS, MEDLINE, Cochrane Library, and SciELO electronic databases, using the following descriptors: Cardiovascular Disease, Rehabilitation Centers, Practice Guideline, Exercise and Risk Stratification in the past 20 years. Results Were selected eight studies addressing methods of risk stratification in patients undergoing exercise. Conclusion None of the methods described could cover every situation the patient can be subjected to; however, they are essential to exercise prescription. PMID:25140477

  5. Design and Testing of a Percutaneously Implantable Fetal Pacemaker

    PubMed Central

    Loeb, Gerald E.; Zhou, Li; Zheng, Kaihui; Nicholson, Adriana; Peck, Raymond A.; Krishnan, Anjana; Silka, Michael; Pruetz, Jay; Chmait, Ramen; Bar-Cohen, Yaniv

    2012-01-01

    We are developing a cardiac pacemaker with a small, cylindrical shape that permits percutaneous implantation into a fetus to treat complete heart block and consequent hydrops fetalis, which can otherwise be fatal. The device uses off-the-shelf components including a rechargeable lithium cell and a highly efficient relaxation oscillator encapsulated in epoxy and glass. A corkscrew electrode made from activated iridium can be screwed into the myocardium, followed by release of the pacemaker and a short, flexible lead entirely within the chest of the fetus to avoid dislodgement from fetal movement. Acute tests in adult rabbits demonstrated the range of electrical parameters required for successful pacing and the feasibility of successfully implanting the device percutaneously under ultrasonic imaging guidance. The lithium cell can be recharged inductively as needed, as indicated by a small decline in the pulsing rate. PMID:22855119

  6. Percutaneously Inject able Fetal Pacemaker: Electrodes, Mechanical Design and Implantation*

    PubMed Central

    Zhou, Li; Chmait, Ramen; Bar-Cohen, Yaniv; Peck, Raymond A.; Loeb, Gerald E.

    2015-01-01

    We are developing a self-contained cardiac pacemaker with a small, cylindrical shape (~320mm) that permits it to be implanted percutaneously into a fetus to treat complete heart block and consequent hydrops fetalis, which is otherwise fatal. The device uses off-the-shelf components including a rechargeable lithium cell and a highly efficient relaxation oscillator encapsulated in epoxy and glass. A corkscrew electrode made from activated iridium can be screwed into the myocardium, followed by release of the pacemaker and a short, flexible lead entirely within the chest of the fetus to avoid dislodgement from fetal movement. The feasibility of implanting the device percutaneously under ultrasonic imaging guidance was demonstrated in acute adult rabbit experiments. PMID:23367442

  7. Ventricular perforation by pacemaker lead repaired with two hemostatic devices

    PubMed Central

    Prestipino, Filippo; Nenna, Antonio; Casacalenda, Adele; Chello, Massimo

    2014-01-01

    INTRODUCTION Cardiac perforation is a rare, but potentially serious, complication of pacemaker implantation that may develop days or weeks after implantation. PRESENTATION OF CASE In the current case, 92-year-old man underwent permanent pacemaker implantation, but he presented 3 weeks later with severe symptoms. Computed tomography showed protrusion of the tip of the ventricular electrode through the right ventricle and into the chest wall. During an urgent surgical intervention, the lead was disconnected and extracted. A sealing hemostatic device and an hemostatic patch were applied to repair the ventricle; the procedure was uneventfull. DISCUSSION This case demonstrates how the correct diagnosis of ventricular perforation is crucial, and should be followed immediately by surgical planning. CONCLUSION The hemostatic patch is a valuable alternative to sutures in patients with thin and fragile ventricular wall, unable to undergo stitching. PMID:25460433

  8. [Local registry of pacemakers implantations: proposals to decrease the infectious risk].

    PubMed

    Tibi, T; Moceri, P; Martin Teule, C; Berkane, N; Talbodec, A; Tannous, J; Zemour, G

    2006-11-01

    The complications of definitive cardiac stimulation must not be forgotten or sub estimate. The aim of our Registry is to compare the complications of the implantation of a pacemaker in the national and international literature. The assessment of our professional practices has been achieved. We suggest improved procedures. The late complications are not exactly known. PMID:17191593

  9. Implantation of a Permanent Pacemaker in a Premature Infant

    PubMed Central

    Sosa, Eugenio S-H; Van Doesburg, Nicholas; Kratz, Christa; Stanley, Paul; Chartrand, Claude

    1988-01-01

    In March 1984 we implanted a permanent, dual-chambered pacemaker in a 2.1-kg premature male infant suffering from congenital atrioventricular block, with an atrial rate of 170 beats per minute, a ventricular rate of 40 beats per minute, and ectopic ventricular escape beats. Through a left anterolateral thoracotomy, we implanted electrodes on the left atrium and left ventricle; through a second incision, in the left flank, we gained access to the retroperitoneal space by finger dissection. The electrodes were then guided through the diaphragmatic sulcus into the retroperitoneal space for attachment to a dual-chambered pacemaker permanently placed in the lumbar region. Our patient was discharged in good condition 23 days after operation and continues, despite some difficulties in establishing optimal pacemaker settings, to enjoy excellent clinical status 55 months after implantation, having moved progressively through pacemaker settings for VVI, DVI, and DDD modes, as his heart has improved. To our knowledge, this is the smallest and first-reported premature infant to be treated successfully for complete heart block with a permanent, physiologic pacemaker. In this surgical procedure, use of epicardial leads decreases the prospect of venous or intracardiac thrombosis; use of long leads situated partly in the chest and partly in the retroperitoneal cavity permits stretching as the child grows; and use of the relatively large peritoneal cavity for placement of the stimulator both protects the unit and permits unimpeded diaphragmatic movement, even in a very small infant. Implantation of this larger, permanent pacemaker, as an alternative to the usual ventricular-demand stimulating electrode, both avoids reoperation and permits flexibility in programming, to meet the changing needs of the growing patient. (Texas Heart Institute Journal 1988;15:128-130) Images PMID:15227266

  10. The cardiac implantable electronic device power source: evolution and revolution.

    PubMed

    Mond, Harry G; Freitag, Gary

    2014-12-01

    Although the first power source for an implantable pacemaker was a rechargeable nickel-cadmium battery, it was rapidly replaced by an unreliable short-life zinc-mercury cell. This sustained the small pacemaker industry until the early 1970s, when the lithium-iodine cell became the dominant power source for low voltage, microampere current, single- and dual-chamber pacemakers. By the early 2000s, a number of significant advances were occurring with pacemaker technology which necessitated that the power source should now provide milliampere current for data logging, telemetric communication, and programming, as well as powering more complicated pacing devices such as biventricular pacemakers, treatment or prevention of atrial tachyarrhythmias, and the integration of innovative physiologic sensors. Because the current delivery of the lithium-iodine battery was inadequate for these functions, other lithium anode chemistries that can provide medium power were introduced. These include lithium-carbon monofluoride, lithium-manganese dioxide, and lithium-silver vanadium oxide/carbon mono-fluoride hybrids. In the early 1980s, the first implantable defibrillators for high voltage therapy used a lithium-vanadium pentoxide battery. With the introduction of the implantable cardioverter defibrillator, the reliable lithium-silver vanadium oxide became the power source. More recently, because of the demands of biventricular pacing, data logging, and telemetry, lithium-manganese dioxide and the hybrid lithium-silver vanadium oxide/carbon mono-fluoride laminate have also been used. Today all cardiac implantable electronic devices are powered by lithium anode batteries. PMID:25387600

  11. [Wide QRS tachycardia preceded by pacemaker spikes].

    PubMed

    Romero, M; Aranda, A; Gómez, F J; Jurado, A

    2014-04-01

    The differential diagnosis and therapeutic management of wide QRS tachycardia preceded by pacemaker spike is presented. The pacemaker-mediated tachycardia, tachycardia fibrillo-flutter in patients with pacemakers, and runaway pacemakers, have a similar surface electrocardiogram, but respond to different therapeutic measures. The tachycardia response to the application of a magnet over the pacemaker could help in the differential diagnosis, and in some cases will be therapeutic, as in the case of a tachycardia-mediated pacemaker. Although these conditions are diagnosed and treated in hospitals with catheterization laboratories using the application programmer over the pacemaker, patients presenting in primary care clinic and emergency forced us to make a diagnosis and treat the haemodynamically unstable patient prior to referral. PMID:23768570

  12. Electrical interference in non-competitive pacemakers

    PubMed Central

    Sowton, E.; Gray, K.; Preston, T.

    1970-01-01

    Patients with 41 implanted non-competitive pacemakers were investigated. A variety of domestic electrical equipment, a motor-car, and a physiotherapy diathermy apparatus were each operated in turn at various ranges from the patient. Interference effects on pacemaker function were assessed on the electrocardiograph. Medtronic demand 5841 pacemakers were stopped by diathermy while Cordis Ectocor pacemakers developed a fast discharge rate. Cordis triggered pacemakers (both Atricor and Ectocor) were sensitive to interference from many items of domestic equipment and the motor car. The Elema EM153 ran at an increased rate when an electric razor was running close to the pacemaker. The Devices demand 2980 and the Medtronic demand 5841 were not affected by the domestic equipment tested. The significance of interference effects is discussed in relation to pacemaker design. Images PMID:5470044

  13. Case study thoracic radiotherapy in an elderly patient with pacemaker: The issue of pacing leads

    SciTech Connect

    Kirova, Youlia M.; Menard, Jean; Chargari, Cyrus; Mazal, Alejandro; Kirov, Krassen

    2012-07-01

    To assess clinical outcome of patients with pacemaker treated with thoracic radiation therapy for T8-T9 paravertebral chloroma. A 92-year-old male patient with chloroma presenting as paravertebral painful and compressive (T8-T9) mass was referred for radiotherapy in the Department of Radiation Oncology, Institut Curie. The patient presented with cardiac dysfunction and a permanent pacemaker that had been implanted prior. The decision of Multidisciplinary Meeting was to deliver 30 Gy in 10 fractions for reducing the symptoms and controlling the tumor growth. The patient received a total dose of 30 Gy in 10 fractions using 4-field conformal radiotherapy with 20-MV photons. The dose to pacemaker was 0.1 Gy but a part of the pacing leads was in the irradiation fields. The patient was treated the first time in the presence of his radiation oncologist and an intensive care unit doctor. Moreover, the function of his pacemaker was monitored during the entire radiotherapy course. No change in pacemaker function was observed during any of the radiotherapy fractions. The radiotherapy was very well tolerated without any side effects. The function of the pacemaker was checked before and after the radiotherapy treatment by the cardiologist and no pacemaker dysfunction was observed. Although updated guidelines are needed with acceptable dose criteria for implantable cardiac devices, it is possible to treat patients with these devices and parts encroaching on the radiation field. This case report shows we were able to safely treat our patient through a multidisciplinary approach, monitoring the patient during each step of the treatment.

  14. Evaluating the Effectiveness of an Interactive Multimedia Computer-based Patient Education Program in Cardiac Rehabilitation.

    ERIC Educational Resources Information Center

    Jenny, Ng Yuen Yee; Fai, Tam Sing

    2001-01-01

    A study compared 48 cardiac patients who used an interactive multimedia computer-assisted patient education program and 48 taught by tutorial. The computer-assisted instructional method resulted in significantly better knowledge about exercise and self-management of chronic diseases. (Contains 29 references.) (JOW)

  15. Activation of the Cardiac Renin-Angiotensin System in High Oxygen-Exposed Newborn Rats: Angiotensin Receptor Blockade Prevents the Developmental Programming of Cardiac Dysfunction.

    PubMed

    Bertagnolli, Mariane; Dios, Anne; Béland-Bonenfant, Sarah; Gascon, Gabrielle; Sutherland, Megan; Lukaszewski, Marie-Amélie; Cloutier, Anik; Paradis, Pierre; Schiffrin, Ernesto L; Nuyt, Anne Monique

    2016-04-01

    Newborn rats exposed to high oxygen (O2), mimicking preterm birth-related neonatal stress, develop later in life cardiac hypertrophy, dysfunction, fibrosis, and activation of the renin-angiotensin system. Cardiac renin-angiotensin system activation in O2-exposed adult rats is characterized by an imbalance in angiotensin (Ang) receptors type 1/2 (AT1/2), with prevailing AT1 expression. To study the role of renin-angiotensin system in the developmental programming of cardiac dysfunction, we assessed Ang receptor expression during neonatal high O2 exposure and whether AT1 receptor blockade prevents cardiac alterations in early adulthood. Sprague-Dawley newborn rats were kept with their mother in 80% O2 or room air (control) from days 3 to 10 (P3-P10) of life. Losartan or water was administered by gavage from P8 to P10 (n=9/group). Rats were studied at P3 (before O2 exposure), P5, P10 (end of O2), and P28. Losartan treatment had no impact on growth or kidney development. AT1 and Ang type 2 receptors were upregulated in the left ventricle by high O2 exposure (P5 and P10), which was prevented by Losartan treatment at P10. Losartan prevented the cardiac AT1/2 imbalance at P28. Losartan decreased cardiac hypertrophy and fibrosis and improved left ventricle fraction of shortening in P28 O2-exposed rats, which was associated with decreased oxidation of calcium/calmodulin-dependent protein kinase II, inhibition of the transforming growth factor-β/SMAD3 pathway, and upregulation of cardiac angiotensin-converting enzyme 2. In conclusion, short-term Ang II blockade during neonatal high O2 prevents the development of cardiac alterations later in life in rats. These findings highlight the key role of neonatal renin-angiotensin system activation in the developmental programming of cardiac dysfunction induced by deleterious neonatal conditions. PMID:26857347

  16. Effect of 1. 5 tesla nuclear magnetic resonance imaging scanner on implanted permanent pacemakers

    SciTech Connect

    Hayes, D.L.; Holmes, D.R. Jr.; Gray, J.E.

    1987-10-01

    Patients with a permanent pacemaker are currently restricted from diagnostic nuclear magnetic resonance (NMR) imaging because of potential adverse effects on the pacemaker by the magnet. Previous work has shown that NMR imaging will result in asynchronous pacing of the pulse generator within a given distance of the magnet. The radiofrequency signal generated by the system may also result in rapid cardiac pacing, which may have deleterious effects. This study utilized a 1.5 tesla unit in an in vivo laboratory animal to evaluate the unit's effects on eight different pulse generators from two manufacturers. All pacemakers functioned in an asynchronous mode when placed within a certain distance of the magnet. In addition, transient reed switch inhibition was observed. Seven of the eight pulse generators paced rapidly when exposed to the radiofrequency signal and there was a dramatic decrease in arterial blood pressure. Whether effective rapid cardiac pacing would occur could not be predicted before exposure to the magnetic resonance unit. Nuclear magnetic resonance imaging with high magnetic fields in patients with a pacemaker should continue to be avoided until the mechanism of the rapid cardiac pacing can be further delineated and either predicted or prevented.

  17. T-type channels in the sino-atrial and atrioventricular pacemaker mechanism.

    PubMed

    Mesirca, Pietro; Torrente, Angelo G; Mangoni, Matteo E

    2014-04-01

    Cardiac automaticity is a fundamental physiological function in vertebrates. Heart rate is under the control of several neurotransmitters and hormones and is permanently adjusted by the autonomic nervous system to match the physiological demand of the organism. Several classes of ion channels and proteins involved in intracellular Ca(2+) handling contribute to pacemaker activity. Voltage-dependent T-type Ca(2+) channels are an integral part of the complex mechanism underlying pacemaking. T-type channels also contribute to impulse conduction in mice and humans. Strikingly, T-type channel isoforms are co-expressed in the cardiac conduction system with other ion channels that play a major role in pacemaking such as f- (HCN4) and L-type Cav1.3 channels. Pharmacologic inhibition of T-type channels reduces the spontaneous activity of isolated pacemaker myocytes of the sino-atrial node, the dominant heart rhythmogenic centre. Target inactivation of T-type Cav3.1 channels abolishes I Ca,T in both sino-atrial and atrioventricular myocytes and reduces the daily heart rate of freely moving mice. Cav3.1 channels contribute also to automaticity of the atrioventricular node and to ventricular escape rhythms, thereby stressing the importance of these channels in automaticity of the whole cardiac conduction system. Accordingly, loss-of-function of Cav3.1 channels contributes to severe form of congenital bradycardia and atrioventricular block in paediatric patients. PMID:24573175

  18. Effect of 1.5 tesla nuclear magnetic resonance imaging scanner on implanted permanent pacemakers.

    PubMed

    Hayes, D L; Holmes, D R; Gray, J E

    1987-10-01

    Patients with a permanent pacemaker are currently restricted from diagnostic nuclear magnetic resonance (NMR) imaging because of potential adverse effects on the pacemaker by the magnet. Previous work has shown that NMR imaging will result in asynchronous pacing of the pulse generator within a given distance of the magnet. The radiofrequency signal generated by the system may also result in rapid cardiac pacing, which may have deleterious effects. This study utilized a 1.5 tesla unit in an in vivo laboratory animal to evaluate the unit's effects on eight different pulse generators from two manufacturers. All pacemakers functioned in an asynchronous mode when placed within a certain distance of the magnet. In addition, transient reed switch inhibition was observed. Seven of the eight pulse generators paced rapidly when exposed to the radiofrequency signal and there was a dramatic decrease in arterial blood pressure. Whether effective rapid cardiac pacing would occur could not be predicted before exposure to the magnetic resonance unit. Nuclear magnetic resonance imaging with high magnetic fields in patients with a pacemaker should continue to be avoided until the mechanism of the rapid cardiac pacing can be further delineated and either predicted or prevented. PMID:3655146

  19. Neuropeptide Secreted from a Pacemaker Activates Neurons to Control a Rhythmic Behavior

    PubMed Central

    Wang, Han; Girskis, Kelly; Janssen, Tom; Chan, Jason P.; Dasgupta, Krishnakali; Knowles, James A.; Schoofs, Liliane; Sieburth, Derek

    2013-01-01

    Summary Background Rhythmic behaviors are driven by endogenous biological clocks in pacemakers, which must reliably transmit timing information to target tissues that execute rhythmic outputs. During the defecation motor program in C. elegans, calcium oscillations in the pacemaker (intestine), which occur about every 50 seconds, trigger rhythmic enteric muscle contractions through downstream GABAergic neurons that innervate enteric muscles. However, the identity of the timing signal released by the pacemaker and the mechanism underlying the delivery of timing information to the GABAergic neurons are unknown. Results Here we show that a neuropeptide-like protein (NLP-40) released by the pacemaker triggers a single rapid calcium transient in the GABAergic neurons during each defecation cycle. We find that mutants lacking nlp-40 have normal pacemaker function, but lack enteric muscle contractions. NLP-40 undergoes calcium-dependent release that is mediated by the calcium sensor, SNT-2/synaptotagmin. We identify AEX-2, the G protein-coupled receptor on the GABAergic neurons, as the receptor of NLP-40. Functional calcium imaging reveals that NLP-40 and AEX-2/GPCR are both necessary for rhythmic activation of these neurons. Furthermore, acute application of synthetic NLP-40-derived peptide depolarizes the GABAergic neurons in vivo. Conclusions Our results show that NLP-40 carries the timing information from the pacemaker via calcium-dependent release and delivers it to the GABAergic neurons by instructing their activation. Thus, we propose that rhythmic release of neuropeptides can deliver temporal information from pacemakers to downstream neurons to execute rhythmic behaviors. PMID:23583549

  20. Transhepatic venous approach to permanent pacemaker placement in a patient with limited central venous access

    PubMed Central

    Siddiqui, Adeel M; Harris, Gregory S; Movahed, Assad; Chiang, Karl S; Chelu, Mihail G; Nekkanti, Rajasekhar

    2015-01-01

    The end-stage renal disease population poses a challenge for obtaining venous access required for life-saving invasive cardiac procedures. In this case report, we describe an adult patient with end-stage renal disease in whom the hepatic vein was the only available access to implant a single-lead permanent cardiac pacemaker. A 63-year-old male with end-stage renal disease on maintenance hemodialysis and permanent atrial fibrillation/atrial flutter presented with symptomatic bradycardia. Imaging studies revealed all traditional central venous access sites to be occluded/non-accessible. With the assistance of vascular interventional radiology, a trans-hepatic venous catheter was placed. This was then used to place a right ventricular pacing lead with close attention to numerous technical aspects. The procedure was completed successfully with placement of a single-lead permanent cardiac pacemaker. PMID:26380831

  1. Transhepatic venous approach to permanent pacemaker placement in a patient with limited central venous access.

    PubMed

    Siddiqui, Adeel M; Harris, Gregory S; Movahed, Assad; Chiang, Karl S; Chelu, Mihail G; Nekkanti, Rajasekhar

    2015-09-16

    The end-stage renal disease population poses a challenge for obtaining venous access required for life-saving invasive cardiac procedures. In this case report, we describe an adult patient with end-stage renal disease in whom the hepatic vein was the only available access to implant a single-lead permanent cardiac pacemaker. A 63-year-old male with end-stage renal disease on maintenance hemodialysis and permanent atrial fibrillation/atrial flutter presented with symptomatic bradycardia. Imaging studies revealed all traditional central venous access sites to be occluded/non-accessible. With the assistance of vascular interventional radiology, a trans-hepatic venous catheter was placed. This was then used to place a right ventricular pacing lead with close attention to numerous technical aspects. The procedure was completed successfully with placement of a single-lead permanent cardiac pacemaker. PMID:26380831

  2. Reconstruction of Hyman's second pacemaker.

    PubMed

    Furman, Seymour; Szarka, George; Layvand, Dmitriy

    2005-05-01

    Though journal articles and newspaper reports suggest that three Hyman pacemakers existed or were intended; a patent, descriptive photographs and a written description of an earlier model and only a photograph of a later model exist. A replica of the earlier has been made based on the patent and description, and a new replica of the second based on a critical deconstruction and analysis of the photograph of the second with a modern circuit duplicating the function of the earlier circuit. Both replicas were "operational" in that stimuli were mimicked though not delivered and neither could under any circumstances actually resuscitate the heart. The design and construction of the second Hyman pacemaker are presented. PMID:15869680

  3. Lithium-iodine pacemaker cell

    SciTech Connect

    Schneider, A.A.; Snyder, S.E.; DeVan, T.; Harney, M.J.; Harney, D.E.

    1980-01-01

    The lithium-iodine pacemaker cell is described as supplied by several manufacturers. The features of each design are discussed along with their effect on energy density, self-discharge and shape of the discharge curve. Differences in performance characteristics are related to morphology of the lithium iodine electrolyte and to the form of the cathode. A new, high-drain cell is mentioned which can supply 60 /mu/a/cm/sup 2/. 10 refs.

  4. Syncope in Patients with Pacemakers.

    PubMed

    Sutton, Richard

    2015-12-01

    Syncope in a pacemaker patient is a serious symptom but it is rarely due a pacemaker system malfunction. Syncope occurs in about 5 % of patients paced for atrioventricular (AV) block in 5 years, 18% in those paced for sinus node disease in 10 years, 20 % of those paced for carotid sinus syndrome in 5 years and 5-55 % of those older patients paced for vasovagal syncope in 2 years. The vastly different results in vasovagal syncope depend on the results of tilt testing, where those with negative tests approach results in pacing for AV block and those with a positive tilt test show no better results than with no pacemaker. The implication of tilt results is that a hypotensive tendency is clearly demonstrated by tilt positivity pointing to syncope recurrence with hypotension. This problem may be addressed by treatment with vasoconstrictor drugs in those who are suited or, more commonly, a reduction or cessation of hypotensive therapy in hypertensive patients. Other causes of syncope such as tachyarrhythmias are rare. The clinical approach to patients who report syncope is detailed. PMID:26835124

  5. Syncope in Patients with Pacemakers

    PubMed Central

    Sutton, Richard

    2015-01-01

    Syncope in a pacemaker patient is a serious symptom but it is rarely due a pacemaker system malfunction. Syncope occurs in about 5 % of patients paced for atrioventricular (AV) block in 5 years, 18% in those paced for sinus node disease in 10 years, 20 % of those paced for carotid sinus syndrome in 5 years and 555 % of those older patients paced for vasovagal syncope in 2 years. The vastly different results in vasovagal syncope depend on the results of tilt testing, where those with negative tests approach results in pacing for AV block and those with a positive tilt test show no better results than with no pacemaker. The implication of tilt results is that a hypotensive tendency is clearly demonstrated by tilt positivity pointing to syncope recurrence with hypotension. This problem may be addressed by treatment with vasoconstrictor drugs in those who are suited or, more commonly, a reduction or cessation of hypotensive therapy in hypertensive patients. Other causes of syncope such as tachyarrhythmias are rare. The clinical approach to patients who report syncope is detailed. PMID:26835124

  6. The challenge of staphylococcal pacemaker endocarditis in a patient with transposition of the great arteries endocarditis in congenital heart disease

    SciTech Connect

    Ch'ng, Julie; Chan, William; Lee, Paul; Joshi, Subodh; Grigg, Leanne E.; Ajani, Andrew E

    2003-06-01

    Staphylococcus aureus is a leading cause of septicaemia and infective endocarditis. The overall incidence of staphylococcal bacteraemia is increasing, contributing to 16% of all hospital-acquired bacteraemias. The use of cardiac pacemakers has revolutionized the management of rhythm disturbances, yet this has also resulted in a group of patients at risk of pacemaker lead endocarditis and seeding in the range of 1% to 7%. We describe a 26-year-old man with transposition of the great arteries who had a pacemaker implanted and presented with S. aureus septicaemia 2 years postpacemaker implantation and went on to develop pacemaker lead endocarditis. This report illustrates the risk of endocarditis in the population with congenital heart disease and an intracardiac device.

  7. NALCN: a regulator of pacemaker activity.

    PubMed

    Lu, Tom Z; Feng, Zhong-Ping

    2012-06-01

    Pacemaker cells play a fundamental role in generating or regulating many essential biological rhythms. Spontaneous pacemaker activity is dependent on the function of an array of ion channels expressed in these cells. Recent characterization of a Na(+) leak channel (NALCN) has linked to its role in conducting the background Na(+) current that depolarizes resting membrane properties of pacemaker neurons. NALCN, along with Unc79 and Unc80, forms a protein complex that is involved in regulating intrinsic membrane and synaptic activities. In this review, we will discuss the current understanding of NALCN channel physiology and its role in regulating cell excitability and pacemaker activity. PMID:22476981

  8. Cardiac rehabilitation programs and health-related quality of life. State of the art.

    PubMed

    Cano de la Cuerda, Roberto; Alguacil Diego, Isabel María; Alonso Martín, Joaquín Jesús; Molero Sánchez, Alberto; Miangolarra Page, Juan Carlos

    2012-01-01

    Cardiovascular disease is the main health problem in developed countries. Prevention is presented as the most effective and efficient primary care intervention, whereas cardiac rehabilitation programs are considered the most effective of secondary prevention interventions; however, these are underused. This literature review examines the effectiveness and the levels of evidence of cardiac rehabilitation programs, their components, their development and role in developed countries, applications in different fields of research and treatment, including their psychological aspects, and their application in heart failure as a paradigm of disease care under this type of intervention. It is completed by a review of the impact of such programs on measures of health-related quality of life, describing the instruments involved in studies in recent scientific literature. PMID:22015019

  9. Petascale computation performance of lightweight multiscale cardiac models using hybrid programming models.

    PubMed

    Pope, Bernard J; Fitch, Blake G; Pitman, Michael C; Rice, John J; Reumann, Matthias

    2011-01-01

    Future multiscale and multiphysics models must use the power of high performance computing (HPC) systems to enable research into human disease, translational medical science, and treatment. Previously we showed that computationally efficient multiscale models will require the use of sophisticated hybrid programming models, mixing distributed message passing processes (e.g. the message passing interface (MPI)) with multithreading (e.g. OpenMP, POSIX pthreads). The objective of this work is to compare the performance of such hybrid programming models when applied to the simulation of a lightweight multiscale cardiac model. Our results show that the hybrid models do not perform favourably when compared to an implementation using only MPI which is in contrast to our results using complex physiological models. Thus, with regards to lightweight multiscale cardiac models, the user may not need to increase programming complexity by using a hybrid programming approach. However, considering that model complexity will increase as well as the HPC system size in both node count and number of cores per node, it is still foreseeable that we will achieve faster than real time multiscale cardiac simulations on these systems using hybrid programming models. PMID:22254341

  10. Predictors of Clinical Anxiety Aggravation at the End of a Cardiac Rehabilitation Program

    PubMed Central

    Saeidi, Mozhgan; Komasi, Saeid; Heydarpour, Behzad; Karim, Hossein; Nalini, Mehdi; Ezzati, Parvin

    2015-01-01

    Background: Anxiety is one of the most primary and common reactions to a cardiac event can lead to hypertension, tachycardia, and high cardiac output. Objectives: To investigate the predictors of clinical anxiety aggravation at the end of a cardiac rehabilitation (CR) program. Patients and Methods: This retrospective study used a database of a CR ward of a hospital in Iran. The demographic and clinical information of 574 patients participating in the CR program from April 2005 through April 2010 were analyzed. In order to determine the predictors of anxiety, binary logistic regression was performed. Results: After adjustment for gender, age and education, the results showed that 16.7% of the patients completed their CR program with increased levels of clinical anxiety. The following study variables were independently predictive of increased anxiety at the end of the CR program: male gender (OR = 2.04, 95% CI = 1.11 to 3.33, P = 0.048), no history of diabetes (OR = 4.24, 95% CI = 172 to 10.44, P = 0.002), family history of cardiac disease (OR = 2.63, 95% CI = 1.03 to 6.74, P = 0.043), and not quitting smoking (OR = 3.29, 95% CI = 1.38 to 7.85, P = 0.007). These variables could explain 9% - 15% of the variance in the dependent variable. Conclusions: It is possible to predict higher anxiety levels at the end of the CR program and implement preventive measures to control anxiety by considering certain demographic and clinical variables. Future studies should assess the predictive power of other variables. PMID:26937419

  11. Successful Treatment of Occipital Neuralgia with Implantable Peripheral Nerve Stimulation in a Pacemaker-Dependent Patient

    PubMed Central

    Chaiban, Gassan; Tolba, Reda; Eissa, Hazem; Lirette, Lesley Smallwood; Almualim, Mohammed; Malaty, Adham; Atallah, Joseph

    2014-01-01

    Background Peripheral nerve stimulation has been used to treat patients with occipital nerverelated chronic headaches who have been unsuccessful with less invasive therapeutic approaches. Patients with pacemaker-dependent cardiac conduction abnormalities require unique consideration prior to the implantation of peripheral nerve stimulators because the placement of the devices may lead to failure of the systems secondary to electromagnetic interference or crosstalk between the devices. Case Report An 86-year-old female who suffered from chronic right-sided cervicogenic headaches and neck pain had received only temporary relief from previous treatments. Additional comorbidities included longstanding pacemaker-dependent atrioventricular node conduction disease. Because the extent to which nerve stimulators electrically interact with pacemakers is unclear, we tunneled the leads to the lumbar region of the back and placed the generator on the contralateral side to the pacemaker to minimize the chance that the 2 devices would interfere. The patient has remained pain free for 1 year since implantation. Conclusion Although no current published trials evaluate the degree of interference between medical devices, case reports increasingly suggest that simultaneous implantation of a spinal cord stimulator and pacemaker is safe as long as precautions are taken and the devices are checked periodically, particularly when the devices are adjusted. PMID:24688344

  12. Calcium transient and sodium-calcium exchange current in human versus rabbit sinoatrial node pacemaker cells.

    PubMed

    Verkerk, Arie O; van Borren, Marcel M G J; Wilders, Ronald

    2013-01-01

    There is an ongoing debate on the mechanism underlying the pacemaker activity of sinoatrial node (SAN) cells, focusing on the relative importance of the "membrane clock" and the "Ca(2+) clock" in the generation of the small net membrane current that depolarizes the cell towards the action potential threshold. Specifically, the debate centers around the question whether the membrane clock-driven hyperpolarization-activated current, I f , which is also known as the "funny current" or "pacemaker current," or the Ca(2+) clock-driven sodium-calcium exchange current, I NaCa, is the main contributor to diastolic depolarization. In our contribution to this journal's "Special Issue on Cardiac Electrophysiology," we present a numerical reconstruction of I f and I NaCa in isolated rabbit and human SAN pacemaker cells based on experimental data on action potentials, I f , and intracellular calcium concentration ([Ca(2+)] i ) that we have acquired from these cells. The human SAN pacemaker cells have a smaller I f , a weaker [Ca(2+)] i transient, and a smaller I NaCa than the rabbit cells. However, when compared to the diastolic net membrane current, I NaCa is of similar size in human and rabbit SAN pacemaker cells, whereas I f is smaller in human than in rabbit cells. PMID:23606816

  13. Pacemaker failure resulting from radiation damage

    SciTech Connect

    Quertermous, T.; Megahy, M.S.; Das Gupta, D.S.; Griem, M.L.

    1983-07-01

    The authors present a case of radiation-induced pacemaker failure. After 2000 rad (20 Gy) of photon irradiation for metastatic bronchogenic carcinoma, the pulse generator circuitry failed, producing a runaway rhythm. This suggests that present pacemaker circuitry may be more susceptible to irradiation than previously believed, and that even modest radiation doses can induce life-threatening arrhythmias.

  14. 21 CFR 870.3670 - Pacemaker charger.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pacemaker charger. 870.3670 Section 870.3670 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger....

  15. 21 CFR 870.3670 - Pacemaker charger.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pacemaker charger. 870.3670 Section 870.3670 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger....

  16. 21 CFR 870.3670 - Pacemaker charger.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker charger. 870.3670 Section 870.3670 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger....

  17. 21 CFR 870.3700 - Pacemaker programmers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pacemaker programmers. 870.3700 Section 870.3700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3700 Pacemaker...

  18. 21 CFR 870.3700 - Pacemaker programmers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pacemaker programmers. 870.3700 Section 870.3700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3700 Pacemaker...

  19. 21 CFR 870.3670 - Pacemaker charger.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pacemaker charger. 870.3670 Section 870.3670 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger....

  20. 21 CFR 870.3670 - Pacemaker charger.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pacemaker charger. 870.3670 Section 870.3670 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger....

  1. 21 CFR 870.3700 - Pacemaker programmers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pacemaker programmers. 870.3700 Section 870.3700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3700 Pacemaker...

  2. 21 CFR 870.3700 - Pacemaker programmers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pacemaker programmers. 870.3700 Section 870.3700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3700 Pacemaker...

  3. 21 CFR 870.3700 - Pacemaker programmers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker programmers. 870.3700 Section 870.3700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3700 Pacemaker...

  4. Runaway pacemaker caused by a stuck accelerometer.

    PubMed

    Nakazato, Y; Nakata, Y; Yasuda, M; Nakazato, K; Tanaka, M; Sumiyoshi, M; Sakurai, H; Yamaguchi, H

    1999-03-01

    We report a case of runaway pacemaker with a ventricular pacing rate of 190 beats/min. The runaway occurred when the accelerometer became stuck due to the magnet application during VVIR pacing. Runaways in modern pacemakers are particularly rare, but they do still occur. The best solution for this phenomenon is generator replacement. PMID:10192868

  5. Pacemaker safety and long-distance running

    PubMed Central

    Bennekers, J.H.; van Mechelen, R.; Meijer, A.

    2004-01-01

    Objective To prove that long-distance running is safe for athletes with pacemaker devices, pacemaker function was evaluated in nine long-distance runners. Method Nine runners participated in a nine-month training programme that involved running for 1000 or 2000 km in preparation for either a full or a half marathon. A professional coach, three cardiologists and a technician all with running experience conducted the training and medical checkups. Commercial heart rate monitors were used during training to assess heart rates at rest, and during exercise and long-distance running. Sensing and pacing functions of the pacemaker system were tested during training sessions as well as during the race. In addition, the ChampionChip (a time registration device used in competition) and the Polar heart rate monitor (a widely used self-monitoring device) were tested for possible interference with the pacemaker. Results All nine athletes completed the Amsterdam 2001 half or full marathon without any pacemaker dysfunction. A short survey after two years showed no pacemaker dysfunction. Conclusion Long-distance running is safe for athletes with pacemaker implants. Overall fitness and sufficient endurance training remain the prerequisites for maintaining the condition necessary for successful completion of a marathon regardless of medical status. In our study, it became clear that for patients who had received a pacemaker because of complete heart block, the upper rate of the pacemaker programme needed to be adjusted to 170 to 180 ppm to insure 1:1 atrio-ventricular synchrony during high atrial rates. It is concluded that there is no a priori reason for cardiologists to advise against long-distance running in athletes with pacemakers. Patients with known or suspected structural heart disease should be screened according the recommendations. PMID:25696264

  6. Analysis of 3D motion of in-vivo pacemaker leads

    NASA Astrophysics Data System (ADS)

    Hoffmann, Kenneth R.; Williams, Benjamin B.; Esthappan, Jacqueline; Chen, Shiuh-Yung J.; Fiebich, Martin; Carroll, John D.; Harauchi, Hajime; Doerr, Vince; Kay, G. Neal; Eberhardt, Allen; Overland, Mary

    1997-04-01

    In vivo analyses of pacemaker lead motion during the cardiac cycle have become important due to incidences of failure of some of the components. For the calculation and evaluation of in vivo stresses in pacemaker leads, the 3D motion of the lead must be determined. To accomplish this, we have developed a technique for calculation of the overall and relative 3D position, and thereby the 3D motion, of in vivo pacemaker leads through the cardiac cycle.Biplane image sequences of patients with pacemakers were acquired for at least two cardiac cycles. After the patient acquisitions, biplane images of a calibration phantom were obtained. The biplane imaging geometries were calculated from the images of the calibration phantom. Points on the electrodes and the lead centerlines were indicated manually in all acquired images. The indicated points along the leads were then fit using a cubic spline. In each projection, the cumulative arclength along the centerlines in two temporally adjacent images was used to identify corresponding points along the centerlines. To overcome the non-synchronicity of the biplane image acquisition, temporal interpolation was performed using these corresponding points based on a linear scheme. For each time point, corresponding points along the lead centerlines in the pairs of biplane images were identified using epipolar lines. The 3D lead centerlines were calculated from the calculated imaging geometries and the corresponding image points along the lead centerlines. From these data, 3D lead motion and the variations of the lead position with time were calculated and evaluated throughout the cardiac cycle. The reproducibility of the indicated lead centerlines was approximately 0.3 mm. The precision of the calculated rotation matrix and translation vector defining image geometry were approximately 2 mm. 3D positions were reproducible to within 2 mm. Relative positional errors were less than 0.3 mm. Lead motion correlated strongly with phases of the cardiac cycle. Our results indicate that complex motions of in vivo pacemaker leads can be precisely determined. Thus, we believe that this technique will provide precise 3D motion and shapes on which to base subsequent stress analysis of pacemaker lead components.

  7. Abnormal permanent pacemaker inhibition by a magnet: a case study.

    PubMed

    Bierman, P Q; Roche, D A; Carlson, L G

    1993-01-01

    Permanent pacemaker evaluation with a magnet is an essential and widely practiced procedure used by cardiologists and electrophysiology nurses for routine pacemaker follow-up. It is generally safely performed. We present a case of a prolonged period of pacemaker inhibition in a pacemaker-dependent patient after routine magnet placement over her permanent pulse generator. PMID:8449758

  8. Pacemakers charging using body energy.

    PubMed

    Bhatia, Dinesh; Bairagi, Sweeti; Goel, Sanat; Jangra, Manoj

    2010-01-01

    Life-saving medical implants like pacemakers and defibrillators face a big drawback that their batteries eventually run out and patients require frequent surgery to have these batteries replaced. With the advent of technology, alternatives can be provided for such surgeries. To power these devices, body energy harvesting techniques may be employed. Some of the power sources are patient's heartbeat, blood flow inside the vessels, movement of the body parts, and the body temperature (heat). Different types of sensors are employed, such as for sensing the energy from the heartbeat the piezoelectric and semiconducting coupled nanowires are used that convert the mechanical energy into electricity. Similarly, for sensing the blood flow energy, nanogenerators driven by ultrasonic waves are used that have the ability to directly convert the hydraulic energy in human body to electrical energy. Another consideration is to use body heat employing biothermal battery to generate electricity using multiple arrays of thermoelectric generators built into an implantable chip. These generators exploit the well-known thermocouple effect. For the biothermal device to work, it needs a 2°C temperature difference across it. But there are many parts of the body where a temperature difference of 5°C exists - typically in the few millimeters just below the skin, where it is planned to place this device. This study focuses on using body heat as an alternative energy source to recharge pacemaker batteries and other medical devices and prevent the possibility of life-risk during repeated surgery. PMID:21814432

  9. Pacemakers charging using body energy

    PubMed Central

    Bhatia, Dinesh; Bairagi, Sweeti; Goel, Sanat; Jangra, Manoj

    2010-01-01

    Life-saving medical implants like pacemakers and defibrillators face a big drawback that their batteries eventually run out and patients require frequent surgery to have these batteries replaced. With the advent of technology, alternatives can be provided for such surgeries. To power these devices, body energy harvesting techniques may be employed. Some of the power sources are patient's heartbeat, blood flow inside the vessels, movement of the body parts, and the body temperature (heat). Different types of sensors are employed, such as for sensing the energy from the heartbeat the piezoelectric and semiconducting coupled nanowires are used that convert the mechanical energy into electricity. Similarly, for sensing the blood flow energy, nanogenerators driven by ultrasonic waves are used that have the ability to directly convert the hydraulic energy in human body to electrical energy. Another consideration is to use body heat employing biothermal battery to generate electricity using multiple arrays of thermoelectric generators built into an implantable chip. These generators exploit the well-known thermocouple effect. For the biothermal device to work, it needs a 2°C temperature difference across it. But there are many parts of the body where a temperature difference of 5°C exists – typically in the few millimeters just below the skin, where it is planned to place this device. This study focuses on using body heat as an alternative energy source to recharge pacemaker batteries and other medical devices and prevent the possibility of life-risk during repeated surgery. PMID:21814432

  10. Damaging effect of therapeutic radiation on programmable pacemakers

    SciTech Connect

    Adamec, R.; Haefliger, J.M.; Killisch, J.P.; Niederer, J.; Jaquet, P.

    1982-03-01

    Two series of present-day pacemakers were tested in vitro with pulsed x-ray radiation. The first series of 12 pacemakers consisted of 10 different types and models of demand pacemakers (VVI). The second series of 13 pacemakers had 9 different types and models of programmable pacemakers. Unlike the first series which showed only mild changes in frequency and pulse width, all but four of the programmable pacemakers presented sudden complete failure after different radiation doses. We conclude that direct pulse radiation at therapeutic levels of programmable pacemakers should be avoided.

  11. Diagnostic imaging and pacemaker implantation in a domestic goat with persistent left cranial vena cava

    PubMed Central

    Ranjan, Ravi; Dosdall, Derek; Norlund, Layne; Higuchi, Koji; Silvernagel, Joshua M.; Olsen, Aaron L.; Davies, Christopher J.; MacLeod, Rob; Marrouche, Nassir F.

    2014-01-01

    Difficulty was encountered with the insertion of a right atrial pacing lead via the left jugular vein during lead and pacemaker implantation in a clinically normal goat as part of an ongoing rapid atrial pacing - induced atrial fibrillation research project. Fluoroscopic visualization of an abnormal lead advancement path prompted angiographic assessment which revealed a persistent left cranial vena cava (PLCVC) and prominent coronary sinus communicating with the right atrium. Angiography facilitated successful advancement and securing of the pacing lead into the right side of the interatrial septum. Cardiac magnetic resonance imaging/magnetic resonance angiography (MRI/MRA) allowed further characterization of this rare venous anomaly. Even though PLCVC has been reported once in a goat, to the authors knowledge this is the first report to include MRI/MRA characterization of PLCVC and prominent coronary sinus with successful cardiac pacemaker implantation using the PLCVC. PMID:24480717

  12. Transforming cardiac rehabilitation into broad-based healthy lifestyle programs to combat noncommunicable disease.

    PubMed

    Arena, Ross; Lavie, Carl J; Cahalin, Lawrence P; Briggs, Paige D; Guizilini, Solange; Daugherty, John; Chan, Wai-Man; Borghi-Silva, Audrey

    2016-01-01

    The current incidence and prevalence of noncommunicable diseases (NCDs) is currently a cause for great concern on a global scale; future projections are no less disconcerting. Unhealthy lifestyle patterns are at the core of the NCD crisis; physical inactivity, excess body mass, poor nutrition and tobacco use are the primary lifestyle factors that substantially increase the risk of developing one or more NCDs. We have now come to recognize that healthy lifestyle interventions are a medical necessity that should be prescribed to all individuals. Perhaps the most well-established model for healthy lifestyle interventions in the current healthcare model is cardiac rehabilitation. To have any hope of improving the outlook for NCDs on a global scale, what is currently known as cardiac rehabilitation must transform into broad-based healthy lifestyle programing, with a shifted focus on primordial and primary prevention. PMID:26511659

  13. SU-D-18C-06: Initial Experience with Implementing MRI Safety Guidelines for Patients with Pacemakers - Medical Physicist Perspective

    SciTech Connect

    James, J; Place, V; Panda, A; Edmonson, H; Felmlee, J; Pooley, R

    2014-06-01

    Purpose: Several institutions have developed MRI guidelines for patients with MR-unsafe or MR-conditional pacemakers. Here we highlight the role of a medical physicist in implementing these guidelines for non-pacemaker dependent patients. Guidelines: Implementing these guidelines requires involvement from several medical specialties and a strong collaboration with the site MRI supervisor to develop a structured workflow. A medical physicist is required to be present during the scan to supervise the MR scanning and to maintain a safety checklist that ensures: 1) uninterrupted patient communication with the technologist, 2) continuous patient physiologic monitoring (e.g. blood pressure and electrocardiography) by a trained nurse, 3) redundant patient vitals monitoring (e.g. pulse oximetry) due to the possibility of in vivo electrocardiography reading fluctuations during image acquisition. A radiologist is strongly recommended to be available to review the images before patients are discharged from the scanner. Pacemaker MRI should be restricted to 1.5T field strength. The MRI sequences should be optimized by the physicist with regards to: a) SAR: limited to <1.5 W/Kg for MR-unsafe pacemakers in normal operating mode, b) RF exposure time: <30 min, c) Coils: use T/R coils but not restricted to such, d) Artifacts: further optimization of sequences whenever image quality is compromised due to the pacemaker. In particular, cardiac, breast and left-shoulder MRIs are most susceptible to these artifacts. Possible strategies to lower the SAR include: a) BW reduction, 2) echo-train-length reduction, 3) increase TR, 4) decrease number of averages, 5) decrease flip angle, 6) reduce slices and/or a combination of all the options. Conclusion: A medical physicist in collaboration with the MR supervisor plays an important role in the supervision/implementation of safe MR scanning of pacemaker patients. Developing and establishing a workflow has enabled our institution to scan over 30 patients with pacemakers without complications, including 3 cardiac MR exams.

  14. Pacemaker failure associated with therapeutic radiation

    SciTech Connect

    Brooks, C.; Mutter, M.

    1988-11-01

    A 48-year-old white man with a multiprogrammable Intramedics 259-01 pacemaker was treated for inoperable lung cancer with a course of cobalt-60 radiotherapy (total 3500 rad). Several weeks subsequent to his last radiation treatment, the patient presented to the emergency department with chest and abdominal pain, shortness of breath, hypotension, and tachycardia. A paced tachycardia was noted, and application of a magnet over the pacemaker completely inhibited its function, allowing a normal sinus rhythm to ensue and the patient's symptoms to be relieved. Pacemaker failure probably was a complication of radiotherapy.

  15. Demonstration of the feasibility of implantation of a skeletal muscle pulse generator for fecal incontinence in a patient with an implanted unipolar DDD pacemaker.

    PubMed

    Konsten, J; Baeten, C G; Den Dulk, K; Spaans, F

    1992-05-01

    Electromagnetic fields and myopotentials from skeletal muscle may interfere with the function of a cardiac pacemaker. A 65-year-old woman with a unipolar DDD cardiac pacemaker underwent dynamic graciloplasty (transposition of the gracilis muscle around the anal canal and subsequent implantation of a bipolar pulse generator to stimulate the gracilis muscle), for the treatment of fecal incontinence. This gracilis pulse generator is turned "off" with an external magnet to allow defecation. Appropriate functioning of these two pulse generators (the cardiac pacemaker and the gracilis pulse generator) was tested during implantation of the gracilis pulse generator and afterwards. It was demonstrated that the combination could be used safely in this patient. PMID:1382284

  16. Program Code Generator for Cardiac Electrophysiology Simulation with Automatic PDE Boundary Condition Handling

    PubMed Central

    Punzalan, Florencio Rusty; Kunieda, Yoshitoshi; Amano, Akira

    2015-01-01

    Clinical and experimental studies involving human hearts can have certain limitations. Methods such as computer simulations can be an important alternative or supplemental tool. Physiological simulation at the tissue or organ level typically involves the handling of partial differential equations (PDEs). Boundary conditions and distributed parameters, such as those used in pharmacokinetics simulation, add to the complexity of the PDE solution. These factors can tailor PDE solutions and their corresponding program code to specific problems. Boundary condition and parameter changes in the customized code are usually prone to errors and time-consuming. We propose a general approach for handling PDEs and boundary conditions in computational models using a replacement scheme for discretization. This study is an extension of a program generator that we introduced in a previous publication. The program generator can generate code for multi-cell simulations of cardiac electrophysiology. Improvements to the system allow it to handle simultaneous equations in the biological function model as well as implicit PDE numerical schemes. The replacement scheme involves substituting all partial differential terms with numerical solution equations. Once the model and boundary equations are discretized with the numerical solution scheme, instances of the equations are generated to undergo dependency analysis. The result of the dependency analysis is then used to generate the program code. The resulting program code are in Java or C programming language. To validate the automatic handling of boundary conditions in the program code generator, we generated simulation code using the FHN, Luo-Rudy 1, and Hund-Rudy cell models and run cell-to-cell coupling and action potential propagation simulations. One of the simulations is based on a published experiment and simulation results are compared with the experimental data. We conclude that the proposed program code generator can be used to generate code for physiological simulations and provides a tool for studying cardiac electrophysiology. PMID:26356082

  17. Program Code Generator for Cardiac Electrophysiology Simulation with Automatic PDE Boundary Condition Handling.

    PubMed

    Punzalan, Florencio Rusty; Kunieda, Yoshitoshi; Amano, Akira

    2015-01-01

    Clinical and experimental studies involving human hearts can have certain limitations. Methods such as computer simulations can be an important alternative or supplemental tool. Physiological simulation at the tissue or organ level typically involves the handling of partial differential equations (PDEs). Boundary conditions and distributed parameters, such as those used in pharmacokinetics simulation, add to the complexity of the PDE solution. These factors can tailor PDE solutions and their corresponding program code to specific problems. Boundary condition and parameter changes in the customized code are usually prone to errors and time-consuming. We propose a general approach for handling PDEs and boundary conditions in computational models using a replacement scheme for discretization. This study is an extension of a program generator that we introduced in a previous publication. The program generator can generate code for multi-cell simulations of cardiac electrophysiology. Improvements to the system allow it to handle simultaneous equations in the biological function model as well as implicit PDE numerical schemes. The replacement scheme involves substituting all partial differential terms with numerical solution equations. Once the model and boundary equations are discretized with the numerical solution scheme, instances of the equations are generated to undergo dependency analysis. The result of the dependency analysis is then used to generate the program code. The resulting program code are in Java or C programming language. To validate the automatic handling of boundary conditions in the program code generator, we generated simulation code using the FHN, Luo-Rudy 1, and Hund-Rudy cell models and run cell-to-cell coupling and action potential propagation simulations. One of the simulations is based on a published experiment and simulation results are compared with the experimental data. We conclude that the proposed program code generator can be used to generate code for physiological simulations and provides a tool for studying cardiac electrophysiology. PMID:26356082

  18. Adjustment of the evoked response sensitivity after hospital discharge in pacemaker patients with automatic ventricular threshold tracking activated.

    PubMed

    Schuchert, A; Ventura, R; Meinertz, T

    2001-02-01

    Automatic threshold tracking in cardiac pacemakers allows ventricular capture verification and self-adaptive pacing output regulation. The Autocapture algorithm detects the evoked response (ER) signal immediately after the pacing pulse to verify the efficacy of ventricular pacing. Before hospital delivery, the ER sensitivity must be programmed individually so that the pacemaker detects the ER signal adequately without sensing lead polarization. The aims of the study were to assess the frequency of patients in whom Autocapture could be activated and whether the ER sensitivity had to be adjusted after hospital discharge. The study included 44 patients who received the VVIR pacemaker Regency SR+ (St. Jude Medical) connected to the model 1450 T pacing lead. ER signal, lead polarization, and ER sensitivity were evaluated before hospital discharge and 1, 3, and 6 months after implantation. The system recommended activating Autocapture in 42 of 44 patients. The mean ER signal was 8.4+/-1.2 mV at discharge, 9.0+/-3.9 mV at month 1, 8.9+/-4.9 mV at month 3, and 9.3+/-4.5 mV at month 6. Polarization was 1.0+/-0.1 mV at discharge, 1.1+/-0.5 mV at month 1, 1.1+/-0.2 mV at month 3, and 1.1+/-0.5 mV at month 6. Mean ER sensitivity was 3.7+/-1.8 mV at discharge, 4.0+/-1.8 mV after 1, 4.1+/-2.2 mV after 3, and 4.1+/-1.8 mV after 6 months. ER sensitivity could remain unadjusted in 14 patients. Programming to a less sensitive ER setting from 2.9+/-1.2 mV to 4.3+/-1.5 mV was possible in 21 patients. Programming to a more sensitive ER setting from 4.1+/-1.1 mV to 2.5+/-0.9 mV was required in nine patients because of the decrease of the ER signal. The automatic threshold tracking algorithm Autocapture could be activated in 95% of patients. Programming to more sensitive ER settings was recommended in 21% of the patients after hospital discharge. Therefore, ER signal and polarization must be checked at each follow-up, as a decrease in ER signal amplitude can make reprogramming of the ER sensitivity necessary. There is no risk for the patient if the ER is not sensed, as high voltage backup stimulation is present. PMID:11270702

  19. Pacemaker

    MedlinePLUS

    ... top of the heart to the bottom, it coordinates the timing of heart cell activity. First, the ... a normal rhythm (a condition called atrial fibrillation ). Coordinate electrical signaling between the upper and lower chambers ...

  20. 50th Anniversary of the first successful permanent pacemaker implantation in the United States: historical review and future directions.

    PubMed

    Beck, Hiroko; Boden, William E; Patibandla, Sushmitha; Kireyev, Dmitriy; Gutpa, Vipul; Campagna, Franklin; Cain, Michael E; Marine, Joseph E

    2010-09-15

    June 2010 marks the 50th anniversary of the first successful human cardiac pacemaker implantation in the United States. On June 6, 1960, in Buffalo, New York, Dr. William Chardack implanted a pacemaker, designed and built by Wilson Greatbatch, an electrical engineer and inventor, in a 77-year old man with complete atrioventricular block, extending the patient's life by 18 months. This landmark event ushered in a new era of implantable cardiac pacemakers with batteries and leads of high reliability and increasing durability. Over the past half century, the field of electrophysiology and implantable devices for the management of cardiac conduction disturbances has evolved dramatically. Today's pacemakers include increasingly complex features such as telemetry monitoring, auto programmability, and hemodynamic sensors. New-generation leads present a sophisticated design with improved geometry and steroid-eluting tips to reduce chronic inflammation, maintaining a low pacing threshold and high sensing capability. The lithium iodide battery remains the mainstay of implantable pacemaker systems, exhibiting a multiple-year lifespan, slow terminal decay, and a reduced size and cost of production. Although Greatbatch's first successful pacemaker implantation remains a seminal scientific contribution to modern cardiovascular disease management, emerging developments in this field may challenge its preeminence. Important challenges such as imaging compatibility, lead durability, and infection prevention are being addressed. Novel concepts such as leadless and biologic pacing are under active investigation. In conclusion, Greatbatch's historic achievement 50 years ago reminds us that technologic progress is timeless, as efforts to enhance clinical outcomes and the quality of life continue unimpeded into the 21st century. PMID:21391322

  1. Changing trends in pacemaker and implantable cardioverter defibrillator generator advisories.

    PubMed

    Maisel, William H; Stevenson, William G; Epstein, Laurence M

    2002-12-01

    Pacemaker and implantable cardioverter defibrillator (ICD) generator recalls and safety alerts (advisories) occur frequently, affect many patients, and are increasing in number and rate. It is unknown if advances in device technology have been accompanied by changing patterns of device advisory type. Weekly FDA Enforcement Reports from January 1991 to December 2000 were analyzed to identify all advisories involving pacemaker and ICD generators. This article represents additional analysis of previously cited advisories and does not contain additional recalls or safety alerts over those that have been previously reported. The 29 advisories (affecting 159,061 devices) from the early 1990s (1991-1995) were compared to the 23 advisories (affecting 364,084 devices) from the late 1990s (1996-2000). While the annual number of device advisories did not change significantly, ICD advisories became more frequent and a three-fold increase in the number of devices affected per advisory was observed. The number of devices affected by hardware advisories increased three-fold, due primarily to a 700-fold increase in electrical/circuitry abnormalities and a 20-fold increase in potential battery/capacitor malfunctions. Other types of hardware abnormalities (defects in the device header, hermetic seal, etc.) became less common. The number of devices recalled due to firmware (computer programming) abnormalities more than doubled. The remarkable technological advances in pacemaker and ICD therapy have been accompanied by changing patterns of device advisory type. Accurate, timely physician and patient notification systems, and routine pacemaker and ICD patient follow-up continue to be of paramount importance. PMID:12520666

  2. How Will a Pacemaker Affect My Lifestyle?

    MedlinePLUS

    ... High-tension wires Metal detectors Industrial welders Electrical generators These devices can disrupt the electrical signaling of ... 2 feet away from industrial welders and electrical generators. Some medical procedures can disrupt your pacemaker. These ...

  3. Implementation of Ultraportable Echocardiography in an Adolescent Sudden Cardiac Arrest Screening Program

    PubMed Central

    Vanhecke, Thomas E; Weber, James E; Ebinger, Matthew; Bonzheim, Kimberly; Tilli, Frank; Rao, Sunilkumar; Osman, Abdulfatah; Silver, Marc; Fliegner, Karsten; Almany, Steve; Haines, David

    2014-01-01

    BACKGROUND Over a 12-month period, adolescent heart-screening programs were performed for identifying at-risk adolescents for sudden cardiac death (SCD) in our community. Novel to our study, all adolescents received an abbreviated, ultraportable echocardiography (UPE). In this report, we describe the use of UPE in this screening program. METHODS AND RESULTS Four hundred thirty-two adolescents underwent cardiac screening with medical history questionnaire, physical examination, 12-lead electrocardiogram (ECG), and an abbreviated transthoracic echocardiographic examination. There were 11 abnormalities identified with uncertain/varying clinical risk significance. In this population, 75 adolescents had a murmur or high ECG voltage, of which only three had subsequent structural abnormalities on echocardiography that may pose risk. Conversely, UPE discovered four adolescents who had a cardiovascular structural abnormality that was not signaled by the 12-lead ECG, medical history questionnaire, and/or physical examination. CONCLUSIONS The utilization of ultraportable, handheld echocardiography is feasible in large-scale adolescent cardiovascular screening programs. UPE appears to be useful for finding additional structural abnormalities and for risk-stratifying abnormalities of uncertain potential of adolescents’ sudden death. PMID:25249762

  4. Development of the Health Incentive Program Questionnaire (HIP-Q) in a cardiac rehabilitation population.

    PubMed

    Mitchell, Marc S; Goodman, Jack M; Alter, David A; Oh, Paul I; Faulkner, Guy E J

    2015-12-01

    The purpose of this study was to develop a questionnaire to facilitate the design of acceptable financial health incentive programs. A multiphase psychometric questionnaire development method was used. Theoretical and literature reviews and three focus groups generated a pool of content areas and items. New items were developed to ensure adequate content coverage. Field testing was conducted with a convenience sample of cardiac rehabilitation (CR) patients (n?=?59) to establish face and construct validity (p?=?0.021) and reliability (intraclass coefficients?=?0.42-0.87). The final questionnaire is comprised of 23 items. This questionnaire builds on previous attempts to explore acceptability by sampling a wider range of instrumental and affective attitudes and by measuring the effect of program features on the likelihood of incentive program participation. Future research is now needed to examine whether tailoring incentives to preferences assessed by the questionnaire improves uptake and effectiveness. PMID:26622917

  5. Mangalith: a new lithium pacemaker battery

    SciTech Connect

    Gerbier, G.; Lehmann, G.

    1980-01-01

    An original lithium battery system is being developed for pacemaker application. The material used, lithium-manganese dioxide, industrially available at the present time for a variety of electronic applications, has been modified and adapted for pacemaker power requirements. The utilization of a different modification of manganese dioxide offers performance advantages. The cell technology is described and performance comparisons between this new cathode material and the industrial counterpart are reported. 7 refs.

  6. Percutaneously injectable fetal pacemaker: electronics, pacing thresholds, and power budget.

    PubMed

    Nicholson, Adriana; Chmait, Ramen; Bar-Cohen, Yaniv; Zheng, Kaihui; Loeb, Gerald E

    2012-01-01

    We are developing a cardiac pacemaker that is designed to be implanted percutaneously into a fetus to treat complete heart block and consequent hydrops fetalis, which is otherwise fatal. One of the most significant considerations for this device is the technical challenges presented by the battery and charging system. The size of the device is limited to about 3 mm in diameter; batteries on this scale have very small charge capacities. The smaller capacity means that the device needs to be designed so that it uses as little current as possible and so that its battery can be recharged wirelessly. We determined the pacing thresholds for a simple relaxation oscillator that can be assembled from discrete, surface mount components and analyzed the power consumption of the device given different electrode configurations and stimulus parameters. An inductive recharging system will be required for some patients; it is feasible within the package constraints and under development. PMID:23367231

  7. Percutaneously Injectable Fetal Pacemaker: Electronics, Pacing Thresholds, and Power Budget

    PubMed Central

    Nicholson, Adriana; Chmait, Ramen; Bar-Cohen, Yaniv; Zheng, Kaihui; Loeb, Gerald E.

    2014-01-01

    We are developing a cardiac pacemaker that is designed to be implanted percutaneously into a fetus to treat complete heart block and consequent hydrops fetalis, which is otherwise fatal. One of the most significant considerations for this device is the technical challenges presented by the battery and charging system. The size of the device is limited to about 3 mm in diameter; batteries on this scale have very small charge capacities. The smaller capacity means that the device needs to be designed so that it uses as little current as possible and so that its battery can be recharged wirelessly. We determined the pacing thresholds for a simple relaxation oscillator that can be assembled from discrete, surface mount components and analyzed the power consumption of the device given different electrode configurations and stimulus parameters. An inductive recharging system will be required for some patients; it is feasible within the package constraints and under development. PMID:23367231

  8. The G-proteingated K+ channel, IKACh, is required for regulation of pacemaker activity and recovery of resting heart rate after sympathetic stimulation

    PubMed Central

    Mesirca, Pietro; Marger, Laurine; Toyoda, Futoshi; Rizzetto, Riccardo; Audoubert, Matthieu; Dubel, Stefan; Torrente, Angelo G.; DiFrancesco, Mattia L.; Muller, Jana Christina; Leoni, Anne-Laure; Couette, Brigitte; Nargeot, Jol; Clapham, David E.; Wickman, Kevin

    2013-01-01

    Parasympathetic regulation of sinoatrial node (SAN) pacemaker activity modulates multiple ion channels to temper heart rate. The functional role of the G-proteinactivated K+ current (IKACh) in the control of SAN pacemaking and heart rate is not completely understood. We have investigated the functional consequences of loss of IKACh in cholinergic regulation of pacemaker activity of SAN cells and in heart rate control under physiological situations mimicking the fight or flight response. We used knockout mice with loss of function of the Girk4 (Kir3.4) gene (Girk4?/? mice), which codes for an integral subunit of the cardiac IKACh channel. SAN pacemaker cells from Girk4?/? mice completely lacked IKACh. Loss of IKACh strongly reduced cholinergic regulation of pacemaker activity of SAN cells and isolated intact hearts. Telemetric recordings of electrocardiograms of freely moving mice showed that heart rate measured over a 24-h recording period was moderately increased (10%) in Girk4?/? animals. Although the relative extent of heart rate regulation of Girk4?/? mice was similar to that of wild-type animals, recovery of resting heart rate after stress, physical exercise, or pharmacological ?-adrenergic stimulation of SAN pacemaking was significantly delayed in Girk4?/? animals. We conclude that IKACh plays a critical role in the kinetics of heart rate recovery to resting levels after sympathetic stimulation or after direct ?-adrenergic stimulation of pacemaker activity. Our study thus uncovers a novel role for IKACh in SAN physiology and heart rate regulation. PMID:23858001

  9. Optimal atrioventricular delay setting determined by QT sensor of implanted DDDR pacemaker.

    PubMed

    Ishikawa, Toshiyuki; Sugano, Teruyasu; Sumita, Shinichi; Toda, Noritaka; Kosuge, Masami; Kobayashi, Izumi; Matsusita, Kohei; Ohkusu, Yasuo; Kimura, Kazuo; Usui, Takashi; Umemura, Satoshi

    2002-02-01

    QT interval (QTI) may change when cardiac function is improved by optimizing the AV delay. QTI is used as the sensor for rate responsive pacemakers. Evoked (e)QTI is measured as the time duration from the ventricular pace-pulse to the T sense point, which is the steepest point of the intracardiac T wave. The relationship between AV delay and eQTI and cardiac function was studied in 13 patients (74.2 +/- 9.3 [SD] years old) with an implanted QT-driven DDDR pacemaker. A special pacemaker software module was downloaded into the pacemaker memory for eQTI data logging. AV delay was set at 100, 120, 150, 180, 210, and 240 ms. Cardiac output (CO) was measured by continuous Doppler echocardiography. eQTI was 343.3 +/- 22.4, 345.1 +/- 22.5, and 343.4 +/- 23.2 ms (P < 0.01, repeated ANOVA) and CO was 4.2 +/- 0.8, 4.6 +/- 0.8, and 4.2 +/- 0.8 L/min (P < 0.0001, repeated ANOVA) when AV delay was set at the AV delay shortened by one step (AV[-]) and prolonged by one step (AV[+]) from the AV delay at which QT interval was maximum (AV[max]) in seven patients, in whom the peak AV delay at which the eQTI was maximal could be identified. eQTI decreased from 341.1 +/- 20.9 to 339.4 +/- 21.1 ms (P < 0.0001) and CO decreased from 4.4 +/- 1.4 to 4.1 +/- 1.3 L/min (P < 0.005) when AV delay was prolonged from AV(max) to AV(+) in all patients. eQTI decreased from 345.1 +/- 22.5 to 343.3 +/- 22.4 ms (P < 0.0005) and CO decreased from 4.6 +/- 0.8 to 4.2 +/- 0.8 L/min (P < 0.05) when AV delay was shortened from AV(max) to AV(-) in seven patients. Thus, CO was maximal when AV delay was set at the AV delay at which eQTI was maximal. In conclusion, the optimal AV delay can be predicted from the eQTI sensed by an implanted pacemaker, and automatic setting of the optimal AV delay can be achieved by the QT sensor of an implanted pacemaker. PMID:11915987

  10. Contact dermatitis after implantable cardiac defibrillator implantation for ventricular tachycardia

    PubMed Central

    Dogan, Pinar; Inci, Sinan; Kuyumcu, Mevlut Serdar; Kus, Ozgur

    2016-01-01

    Summary Pacemaker contact sensitivity is a rare condition. Less than 30 reports of pacemaker skin reactions have been described. We report a 57-year-old woman who underwent an implantable cardiac defibrillator (ICD) implantation for ventricular tachycardia. A skin patch test was positive on almost all components of the pacemaker system. She was treated with topical corticosteroids and skin lesions resolved within 2 weeks. Because of widespread use of various devices, we will see this more often and therefore it is important to recognize this problem and its effective management. PMID:26989652

  11. 'This is a forever project': supporting lifestyle changes in a regional Queensland community-based cardiac rehabilitation program.

    PubMed

    Madsen, Wendy

    2013-01-01

    Cardiac rehabilitation programs throughout the world have struggled for several years to attract more participants and facilitate behaviour changes in these clients. Over the past few years, there has been an increased level of attention in the role that self-efficacy and social support may play in this respect. The main aim of this study was to explore self-efficacy and social support within a regional, community-based cardiac rehabilitation program that does not adhere to traditional cardiac rehabilitation structures. Twelve participants were interviewed and two major themes emerged from the thematic analysis of the interview transcripts: making personal lifestyle changes; and supportive environment for lifestyle changes. Although this study is exploratory in nature, it has highlighted the significance of social support from within a program as opposed to participants' friends and family, the subject of most social-support research. It also contributes to the challenges others are starting to make regarding the limited timeframes associated with traditional cardiac rehabilitation programs, suggesting more time may be needed to build firmer psychosocial foundations for behaviour change after cardiac events. PMID:22950845

  12. Radiology of cardiac devices and their complications

    PubMed Central

    Dipoce, J; Spindola-Franco, H

    2015-01-01

    This article familiarizes the reader with several different cardiac devices including pacemakers and implantable cardioverter defibrillators, intra-aortic balloon pumps, ventricular assist devices, valve replacements and repairs, shunt-occluding devices and passive constraint devices. Many cardiac devices are routinely encountered in clinical practice. Other devices are in the early stages of development, but circumstances suggest that they too will become commonly found. The radiologist must be familiar with these devices and their complications. PMID:25411826

  13. Update on arrhythmias and cardiac pacing 2013.

    PubMed

    Almendral, Jesús; Pombo, Marta; Martínez-Alday, Jesús; González-Rebollo, José M; Rodríguez-Font, Enrique; Martínez-Ferrer, José; Castellanos, Eduardo; García-Fernández, F Javier; Ruiz-Mateas, Francisco

    2014-04-01

    This report discusses a selection of the most relevant articles on cardiac arrhythmias and pacing published in 2013. The first section discusses arrhythmias, classified as regular paroxysmal supraventricular tachyarrhythmias, atrial fibrillation, and ventricular arrhythmias, together with their treatment by means of an implantable cardioverter defibrillator. The next section reviews cardiac pacing, subdivided into resynchronization therapy, remote monitoring of implantable devices, and pacemakers. The final section discusses syncope. PMID:24774592

  14. Pacemaker leads: performance and progress.

    PubMed

    de Voogt, W G

    1999-03-11

    Pacing leads remain the "weaker link" of the permanent pacing system. Lead failure has been an issue since the beginning of implantable pacemaker therapy. Modern electronics have brought about considerable progress in pacing technology, but lead design has been slower to evolve and problems persist. IS-1 standardization must be considered a significant advance, but some issues regarding IS-1 standardization persist and have been the cause of some compatibility problems. With respect to lead insulation, silicone has proved to offer total reliability for > 30 years. In the search for better handling characteristics, polyurethane 80A was employed for bipolar leads, but it failed to demonstrate satisfactory insulating properties. New insulation materials, such as ethylene-fluoro-ethylene (ETFE), and coated wire technology look promising, having shown 99.32% survival at 5-year follow-up. Reliability is the main objective in lead design, but leads should provide low battery consumption as well. Low coil resistance, with high electrode impedance in steroid-eluting leads, is the standard at present. Low polarization is a desirable property for 2 main reasons: (1) in conjunction with low-threshold leads, it decreases battery consumption; and (2) it allows capture detection and, therefore, safer pacing at low battery consumption. Lead tip design as well as pacing pulse configuration can influence polarization. PMID:10089864

  15. Mutual entrainment and electrical coupling as mechanisms for synchronous firing of rabbit sino-atrial pace-maker cells.

    PubMed Central

    Jalife, J

    1984-01-01

    The mechanisms of synchronous firing of cardiac pace-makers were studied using thin (0.3-0.5 mm) rabbit sino-atrial (s.a.) node strips placed in a three-compartment tissue bath. Superfusion of the central segment (1 mm in length) with ion-free sucrose solution permitted the electrical insulation of the external segments and the development of two independent pace-maker 'centres': one fast (F); one slow (S). An external shunt pathway was used to modulate the degree of coupling between F and S. Superfusion of the central segment with Tyrode solution containing heptanol (3.5 mM) instead of sucrose induced progressive decrease in the amplitude of responses in this segment and led to progressive loss of F:S synchronization. Eventually the two pace-makers became totally independent from each other. These changes were reversible upon wash-out of heptanol. When a pace-maker centre was within the range of influence of local circuit (i.e. electronic) currents from the pace-maker in the opposite side of the sucrose (or heptanol) compartment, its period was prolonged or abbreviated, depending on phase and frequency relations. Dynamic F:S interactions at various degrees of electrical coupling resulted in mutual entrainment with both pace-makers beating at simple harmonic (i.e. 1:1, 2:1, 1:2, etc.) or more complex (3:2, 5:4, etc.) ratios that depended on the degree of coupling and the intrinsic periods of the individual pace-maker centres. The patterns of synchronization could be predicted by the phasic sensitivity of each pace-maker to brief electrotonic inputs. The results suggest that when two individual pace-maker cells are connected through low resistance junctions, the period resulting from their mutual entrainment should be a function of their respective intrinsic frequencies, their phase relations and the degree of electrical coupling. The data further suggest that the heart beat is initiated by a 'democratic' type of synchronous firing of cells in the s.a. node, with each pace-maker cell contributing to an aggregate signal and involving mutual entrainment between cells. PMID:6097670

  16. Mutual entrainment of bilaterally distributed circadian pacemaker.

    PubMed Central

    Page, T L; Caldarola, P C; Pittendrigh, C S

    1977-01-01

    The interactions between the bilaterally distributed components of the circadin system that controls the locomotor activity rhythm of the cockroach Leucophaea maderae were investigated in a series of surgical lesion experiments. Complete excision of one optic lobe (either right or left) or its surgical isolation from the central nervous system had no effect on the animals' ability to free-run in constant darkness nor was there any indication, as judged by postoperative pi values of any difference between left and right lobe pacemakers. However, these surgical procedures consistently resulted in a significant increase in tau over preoperative value while optic nerve section had no effect on tau. The propostion is developed that the left and right pacemakers in the two optic lobes are mutally coupled and that the compound pacemaker's period is shorter than either of its constituent pacemakers. It was also found that the integrity of either compound eye is sufficient to assure entrainment of both left and right pacemakers. Images PMID:265571

  17. Mutual entrainment of bilaterally distributed circadian pacemaker.

    PubMed

    Page, T L; Caldarola, P C; Pittendrigh, C S

    1977-03-01

    The interactions between the bilaterally distributed components of the circadin system that controls the locomotor activity rhythm of the cockroach Leucophaea maderae were investigated in a series of surgical lesion experiments. Complete excision of one optic lobe (either right or left) or its surgical isolation from the central nervous system had no effect on the animals' ability to free-run in constant darkness nor was there any indication, as judged by postoperative pi values of any difference between left and right lobe pacemakers. However, these surgical procedures consistently resulted in a significant increase in tau over preoperative value while optic nerve section had no effect on tau. The propostion is developed that the left and right pacemakers in the two optic lobes are mutally coupled and that the compound pacemaker's period is shorter than either of its constituent pacemakers. It was also found that the integrity of either compound eye is sufficient to assure entrainment of both left and right pacemakers. PMID:265571

  18. 21 CFR 870.3730 - Pacemaker service tools.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pacemaker service tools. 870.3730 Section 870.3730...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices 870.3730 Pacemaker service tools. (a) Identification. Pacemaker service tools are devices such as screwdrivers and Allen...

  19. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pacemaker electrode function tester. 870.3720... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices 870.3720 Pacemaker electrode function tester. (a) Identification. A pacemaker electrode function tester is a device which...

  20. 21 CFR 870.3730 - Pacemaker service tools.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker service tools. 870.3730 Section 870.3730...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices 870.3730 Pacemaker service tools. (a) Identification. Pacemaker service tools are devices such as screwdrivers and Allen...

  1. 21 CFR 870.3730 - Pacemaker service tools.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pacemaker service tools. 870.3730 Section 870.3730...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices 870.3730 Pacemaker service tools. (a) Identification. Pacemaker service tools are devices such as screwdrivers and Allen...

  2. 21 CFR 870.3690 - Pacemaker test magnet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker test magnet. 870.3690 Section 870.3690...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3690 Pacemaker test magnet. (a) Identification. A pacemaker test magnet is a device used to test an inhibited or triggered...

  3. 21 CFR 870.3690 - Pacemaker test magnet.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pacemaker test magnet. 870.3690 Section 870.3690...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3690 Pacemaker test magnet. (a) Identification. A pacemaker test magnet is a device used to test an inhibited or triggered...

  4. Effect of Cardiac Rehabilitation Program on Heart Rate Recovery in Coronary Heart Disease

    PubMed Central

    Mahdavi Anari, Leila; Ghanbari-Firoozabadi, Mahdieh; Ansari, Zahra; Emami, Mahmoud; Vafaii Nasab, Mohammadreza; Nemaiande, Mahdieh; Boostany, Fatemeh; Neishaboury, Mohamadreza

    2015-01-01

    Background: It has been suggested that the autonomic system function and the metabolic syndrome can significantly affect patients' survival. The aim of the current study was to investigate the impact of the cardiac rehabilitation program on the autonomic system balance in patients with coronary artery disease. Methods: Patients with a previous diagnosis of coronary artery disease who were referred to the Cardiovascular Rehabilitation Center of Afshar Hospital (Yazd, Iran) between March and November 2011 were enrolled. All the patients participated in rehabilitation sessions 3 times a week for 12 weeks. Heart rate recovery (HRR) was measured as an indicator of the autonomic system balance. In order to calculate HRR, the maximum heart rate during the exercise test was recorded. At the end of the exercise test, the patients were asked to sit down without having a cooldown period and their heart rate was recorded again after 1 minute. The difference between these 2 measurements was considered as HRR. Results: A total of 108 patients, including 86 (79.6%) men and 22 (20.4%) women, completed the rehabilitation course. The mean age of the study participants was 58.25 ± 9.83 years. A statistically significant improvement was observed in HRR (p value = 0.040). Significant declines were also observed in the patients' waist circumference (p value < 0.001) and systolic and diastolic blood pressures (p value = 0.018 and 0.003, respectively). A decreasing trend was observed in the patients' body mass index, but it failed to reach statistical significance (p value = 0.063). No statistically meaningful changes were noted in fasting blood glucose (p value = 0.171), high-density lipoprotein (p value = 0.070), or triglyceride concentrations (p value = 0.149). Conclusion: The cardiac rehabilitation program may help to improve HRR and several components of the metabolic syndrome in patients with coronary heart disease. PMID:26985205

  5. Pacemaker-induced transient asynchrony suppresses heart failure progression.

    PubMed

    Kirk, Jonathan A; Chakir, Khalid; Lee, Kyoung Hwan; Karst, Edward; Holewinski, Ronald J; Pironti, Gianluigi; Tunin, Richard S; Pozios, Iraklis; Abraham, Theodore P; de Tombe, Pieter; Rockman, Howard A; Van Eyk, Jennifer E; Craig, Roger; Farazi, Taraneh G; Kass, David A

    2015-12-23

    Uncoordinated contraction from electromechanical delay worsens heart failure pathophysiology and prognosis, but restoring coordination with biventricular pacing, known as cardiac resynchronization therapy (CRT), improves both. However, not every patient qualifies for CRT. We show that heart failure with synchronous contraction is improved by inducing dyssynchrony for 6 hours daily by right ventricular pacing using an intracardiac pacing device, in a process we call pacemaker-induced transient asynchrony (PITA). In dogs with heart failure induced by 6 weeks of atrial tachypacing, PITA (starting on week 3) suppressed progressive cardiac dilation as well as chamber and myocyte dysfunction. PITA enhanced β-adrenergic responsiveness in vivo and normalized it in myocytes. Myofilament calcium response declined in dogs with synchronous heart failure, which was accompanied by sarcomere disarray and generation of myofibers with severely reduced function, and these changes were absent in PITA-treated hearts. The benefits of PITA were not replicated when the same number of right ventricular paced beats was randomly distributed throughout the day, indicating that continuity of dyssynchrony exposure is necessary to trigger the beneficial biological response upon resynchronization. These results suggest that PITA could bring the benefits of CRT to the many heart failure patients with synchronous contraction who are not CRT candidates. PMID:26702095

  6. "Pacecare"--a computerized database for pacemaker follow-up.

    PubMed

    Strathmore, N; Mond, H; Hunt, D; Graham, D; Cowling, R; Hale, G; Pate, B

    1990-12-01

    A computerized database for pacemaker follow-up has been designed to run on IBM compatible hardware and to accept pulse generator and lead models of all manufacturers. Stored data includes patient, physician and implant details, indications for pacing, underlying rhythm, complications and management, program settings, and follow-up measurements. Typing is minimized by the use of "pop-up" lists and prepared pulse generator template displays. At each follow-up visit a patient's file is retrieved by surname or number, a visit record created, and measurements documented. As the template of the previous visit is used, recording of the clinic visit takes less than 1 minute. Changes in pacing rates (base or magnet), pulse widths, lead thresholds, lead impedance, and battery cell impedance can be displayed graphically for immediate recognition of end-of-life parameters or suspected malfunction. The program will print patient, implantation and clinic visit summary reports, clinic appointment lists, letters to patients, and annual reports. Two Melbourne hospitals have now entered over 3,600 patients into the database. Valuable information has been obtained regarding implantation details and trends with pulse generator and lead usage. Pacecare is a sophisticated, yet user friendly, computerized database for pacemaker follow-up. Recording of clinic visits is fast and changes in testing parameters can be recognized immediately. PMID:1704542

  7. Cardiac arrest in kearns-sayre syndrome.

    PubMed

    van Beynum, Ingrid; Morava, Eva; Taher, Marjan; Rodenburg, Richard J; Karteszi, Judit; Toth, Kalman; Szabados, Eszter

    2012-01-01

    The prognosis of progressive ophthalmoplegia in patients with large-scale mitochondrial DNA deletions is highly variable and almost unpredictable. The risk to develop cardiac involvement and sudden cardiac death is strikingly high, especially in patients with Kearns-Sayre syndrome (KSS). The most typical cardiac complications of the disease are conduction defects, which usually begin with left anterior fascicular block with or without right bundle branch block (RBBB), progressing sometimes rapidly to complete atrioventricular block. Other cardiac manifestations reported are first or second degree of AV block, QT prolongation, torsades de pointes ventricular tachycardia, and rarely dilated cardiomyopathy. Most frequently syncope, sometimes even sudden cardiac death, is the first clinical sign of the cardiac disease in KSS. Due to these life-threatening cardiac conditions, patients should be carefully monitored for cardiac signs and symptoms and pacemaker implantation should be suggested early to avoid sudden cardiac arrest in KSS.Here, we present two cases of KSS with life-threatening syncope due to complete atrioventricular block. To emphasize the importance of an early pacemaker implantation, we review the literature on cardiac complications in KSS in the last 20 years. In almost all of the reviewed cases, ophthalmoplegia or ptosis was present before the cardiac manifestations. In most of the cases, syncope was the first symptom of the cardiac involvement. There was no correlation between the age of the onset of the disease and the onset of cardiac manifestations.With our current report, we increase awareness for life-threatening cardiac complications in patients with KSS. PMID:23430846

  8. [Computerized follow-up cards for ambulatory patients with implanted pacemaker or defibrillator].

    PubMed

    Santomauro, M; Damiano, M; Senatore, G; Solimene, F; Marrazzo, N; Betocchi, S; Chiariello, M

    1996-10-01

    The follow up of pacemaker and defibrillator dependent patients has a significant role for both the evaluation of pacing effectiveness and check of hemodynamic advantages about patient's quality of life. The bulky paper archives are often inaccurate, hampering the consultation. At present the paper card is the only document which can be utilized to record some data concerning the implant and patient clinical story. Therefore, there is the necessity for a card that can include all patient's data, and the implant and programming pacemaker/defibrillator data during follow up. This new pacemaker card has portable file or data-base including shared data with safety mechanism, which can be utilized in several controls by different users (physicians, hospital ward, primary care units, insurance companies). The pacemaker card includes a chip that permits to store a considerable amount of data; it can be update in every further medical control, in observance of laws. The card Chip Operating System (C.O.S.) consists of a microchip with a memory completely managed by the operating system inside the chip itself. The card can be read by means of a GCR-200 modem linked with a PC IBM-compatible computer and the data can be updated during the follow up. The pacemaker-defibrillator card will appear immediately on screen, and it can be printed, updated and/or modified by a Microsoft Windows operating programme. With this pacemaker card we are able to ensure serviceable medical work, particularly in terms of cost/benefit ratio giving to patient more and more reasoning and safe service. PMID:9005162

  9. Clinical Outcome After Permanent Pacemaker Implantation in Patients With a High Percentage of Ventricular Pacing.

    PubMed

    Sakatani, Tomohiko; Sakamoto, Akira; Kawamura, Kohei; Tanigaki, Toru; Tsubakimoto, Yoshinori; Isodono, Koji; Kimura, Shinzo; Matsuo, Akiko; Inoue, Keiji; Kitamura, Makoto; Fujita, Hiroshi

    2015-12-01

    Previous reports have suggested that right ventricular apical pacing may lead to cardiac dysfunction. Septal pacing is thought to be superior to apical pacing in the prevention of cardiac dyssynchrony, however, there have been no reports on the contribution of septal pacing to improving clinical outcome.We retrospectively evaluated factors associated with cardiac events in patients with right ventricular pacing.The study population consisted of 256 consecutive patients newly implanted with permanent pacemakers and followed-up for 29 18 months. Cardiac events, consisting of cardiac death or heart failure requiring hospitalization, occurred in 22 patients. Kaplan-Meier curves revealed that patients with a high percentage of ventricular pacing (> 90%, n = 101, group H) had a higher incidence of cardiac events than patients with a low percentage of ventricular pacing (< 10%, n = 83, group L) (P = 0.002). In group H, multivariate analysis showed that age (HR: 1.174, 95%CI: 1.066-1.291, P = 0.001), ejection fraction (EF) (HR: 0.898, 95%CI: 0.836-0.964, P = 0.003), QRS duration during cardiac pacing (HR: 1.059, 95%CI: 1.017-1.103, P = 0.006), and existing basal cardiac diseases (HR: 13.080, 95%CI: 2.463-69.479, P = 0.003) were significant predictors of cardiac events, although pacing site had no significant association with prognosis (P = 0.56).Higher age, lower EF, longer QRS duration during cardiac pacing, and existing basal cardiac diseases are associated with poor prognosis in patients with a high percentage of ventricular pacing. PMID:26549389

  10. Impact of an endurance training program on exercise-induced cardiac biomarker release.

    PubMed

    Legaz-Arrese, Alejandro; López-Laval, Isaac; George, Keith; Puente-Lanzarote, Juan José; Mayolas-Pi, Carmen; Serrano-Ostáriz, Enrique; Revilla-Martí, Pablo; Moliner-Urdiales, Diego; Reverter-Masià, Joaquín

    2015-04-15

    We evaluated the influence of a 14-wk endurance running program on the exercise-induced release of high-sensitivity cardiac troponin T (hs-cTnT) and NH2-terminal pro-brain natriuretic peptide (NT-proBNP). Fifty-eight untrained participants were randomized to supervised endurance exercise (14 wk, 3-4 days/wk, 120-240 min/wk, 65-85% of maximum heart rate) or a control group. At baseline and after the training program, hs-cTnT and NT-proBNP were assessed before and 5 min, 1 h, 3 h, 6 h, 12 h, and 24 h after a 60-min maximal running test. Before training, hs-cTnT was significantly elevated in both groups with acute exercise (P < 0.0001) with no between-group differences. There was considerable heterogeneity in peak hs-cTnT concentration with the upper reference limit exceeded in 71% of the exercise tests. After training, both baseline and postexercise hs-cTnT were significantly higher compared with pretraining and the response of the control group (P = 0.008). Acute exercise led to a small but significant increase in NT-proBNP, but this was not mediated by training (P = 0.121). In summary, a controlled endurance training intervention resulted in higher pre- and postexercise values of hs-cTnT with no changes in NT-proBNP. PMID:25681432

  11. Performance of hybrid programming models for multiscale cardiac simulations: preparing for petascale computation.

    PubMed

    Pope, Bernard J; Fitch, Blake G; Pitman, Michael C; Rice, John J; Reumann, Matthias

    2011-10-01

    Future multiscale and multiphysics models that support research into human disease, translational medical science, and treatment can utilize the power of high-performance computing (HPC) systems. We anticipate that computationally efficient multiscale models will require the use of sophisticated hybrid programming models, mixing distributed message-passing processes [e.g., the message-passing interface (MPI)] with multithreading (e.g., OpenMP, Pthreads). The objective of this study is to compare the performance of such hybrid programming models when applied to the simulation of a realistic physiological multiscale model of the heart. Our results show that the hybrid models perform favorably when compared to an implementation using only the MPI and, furthermore, that OpenMP in combination with the MPI provides a satisfactory compromise between performance and code complexity. Having the ability to use threads within MPI processes enables the sophisticated use of all processor cores for both computation and communication phases. Considering that HPC systems in 2012 will have two orders of magnitude more cores than what was used in this study, we believe that faster than real-time multiscale cardiac simulations can be achieved on these systems. PMID:21768044

  12. Electromagnetic interference of pacemakers by mobile phones.

    PubMed

    Irnich, W; Batz, L; Mller, R; Tobisch, R

    1996-10-01

    The topic of interference of pacemakers by mobile phones has evoked a surprisingly strong interest, not only in pacemaker patients, but also in the public opinion. The latter is the more surprising, as in the past, the problem of interference has scarcely found the attention that it deserves in the interest of the patient. It was the intention of our investigation to test as many pacemaker models as possible to determine whether incompatibility with mobile phones of different modes may exist, using an in vitro measuring setup. We had access to 231 different models of 20 manufacturers. During the measurements, a pulse generator together with a suitable lead was situated in a 0.9 g/L saline solution, and the antenna of a mobile phone was positioned as close as possible. If the pulse generator was disturbed, the antenna was elevated until interference ceased. The gap in which interference occurred was defined as "maximum interference distance." All three nets existing in Germany, the C-net (450 MHz, analogue), the D-net (900 MHz, digital pulsed), and the E-net (1,800 MHz, digital pulsed) were tested in succession. Out of 231 pulse generator models, 103 pieces corresponding to 44.6% were influenced either by C- or D-net, if both results were totaled. However, this view is misleading as no patient will use C- and D-net phones simultaneously. Separated into C- or D-net interference, the result is 30.7% for C or 34.2% for D, respectively, of all models tested. The susceptible models represent 18.6% or 27% of today's living patients, respectively. All models were resistant to the E-net. With respect to D-net phones, all pacemakers of six manufacturers proved to be unaffected. Eleven other manufacturers possessed affected and unaffected models as well. A C-net phone only prolonged up to five pacemaker periods within 10 seconds during dialing without substantial impairment to the patient. Bipolar pacemakers are as susceptible as unipolar ones. The following advice for patients and physicians can be derived from our investigations: though 27% of all patients may have problems with D-net phones (not C- or E-net), the application should generally not be questioned. On the contrary, patients with susceptible devices should be advised that a distance of 20 cm is sufficient to guarantee integrity of the pacemaker with respect to hand held phones. Portables, on the other hand, should have a distance of about 0.5 m. Pacemaker patients really suffering from mobile phones are very rare unless the phone is just positioned in the pocket over the pulse generator. The contralateral pocket or the belt position guarantees, in 99% of all patients, undisturbed operation of the pacemaker. A risk analysis reveals that the portion of patients really suffering from mobile phones is about 1 out of 100,000. Nevertheless, it would be desirable in the future if implanting physicians would use only pacemakers with immunity against mobile phones as guaranteed by the manufacturers. PMID:8904533

  13. Measuring pacemaker dose: A clinical perspective

    SciTech Connect

    Studenski, Matthew T.; Xiao Ying; Harrison, Amy S.

    2012-07-01

    Recently in our clinic, we have seen an increased number of patients presenting with pacemakers and defibrillators. Precautions are taken to develop a treatment plan that minimizes the dose to the pacemaker because of the adverse effects of radiation on the electronics. Here we analyze different dosimeters to determine which is the most accurate in measuring pacemaker or defibrillator dose while at the same time not requiring a significant investment in time to maintain an efficient workflow in the clinic. The dosimeters analyzed here were ion chambers, diodes, metal-oxide-semiconductor field effect transistor (MOSFETs), and optically stimulated luminescence (OSL) dosimeters. A simple phantom was used to quantify the angular and energy dependence of each dosimeter. Next, 8 patients plans were delivered to a Rando phantom with all the dosimeters located where the pacemaker would be, and the measurements were compared with the predicted dose. A cone beam computed tomography (CBCT) image was obtained to determine the dosimeter response in the kilovoltage energy range. In terms of the angular and energy dependence of the dosimeters, the ion chamber and diode were the most stable. For the clinical cases, all the dosimeters match relatively well with the predicted dose, although the ideal dosimeter to use is case dependent. The dosimeters, especially the MOSFETS, tend to be less accurate for the plans, with many lateral beams. Because of their efficiency, we recommend using a MOSFET or a diode to measure the dose. If a discrepancy is observed between the measured and expected dose (especially when the pacemaker to field edge is <10 cm), we recommend analyzing the treatment plan to see whether there are many lateral beams. Follow-up with another dosimeter rather than repeating multiple times with the same type of dosimeter. All dosimeters should be placed after the CBCT has been acquired.

  14. Sinus Node Dysfunction Requiring Permanent Pacemaker Implantation in a Young Adult with Klinefelter Syndrome

    PubMed Central

    Karagz, Ahmet; Dikba?, O?uz; Teker, Erhan; Vural, Asl?; Gnayd?n, Zeki Yksel; Bekta?, Osman

    2015-01-01

    Patient: Male, 22 Final Diagnosis: Sinus node dysfunction Symptoms: Bradycardia lassitude Medication: Clinical Procedure: Pacemaker implantation Specialty: Cardiology Objective: Unusual clinical course Background: Klinefelter syndrome is the most common genetic cause of male infertility and affects approximately 1 in 500 live births. Although accompanying cardiac disorder is not a specific feature of Klinefelter syndrome, rarely associated anomalies such as mitral valve prolapse, atrial septal defect, ventricular septal defect, tetralogy of Fallot, patent ductus arteriosus, and hypertrophic obstructive cardiomyopathy have been reported. A clear association between Klinefelter syndrome and arrhythmic disorders has not yet been demonstrated. Case Report: We report a case of a sinus node dysfunction that required permanent pacemaker implantation in a young adult with Klinefelter syndrome. The patient was consulted to cardiology clinic due to bradycardia. On physical examination, no cardiac abnormality was detected except for bradycardia. Holter results showed sinus arrhythmia with a minimum heart rate of 33 bpm and maximum of 154 Bpm. There were 3612 ventricular premature beats, 30 ventricular pairs, 804 supraventricular premature beats, 7 supraventricular pairs, and 4 supraventricular runs, the longest of which was 5 beats. The patient had defined dizziness and nausea during Holter monitoring. Electrophysiological study (EPS) was planned because existing findings indicated risk of cardiac syncope. Findings of EPS were interpreted as sinus node dysfunction. A permanent pacemaker implantation was performed and the patient has been free of symptoms since. Conclusions: This concomitance should be kept in mind when examining patients with Klinefelter syndrome with bradycardia and/or syncope. It is easily mistaken for epilepsy, which is a commonly encountered abnormality in Klinefelter syndrome. PMID:25744562

  15. Pacemaker failures characterized by continuous direct current leakage.

    PubMed

    Fisher, J D; Furman, S; Parker, B; Escher, D J

    1976-06-01

    Pulse generator failure caused by continuous leakage of direct current through an output capacitor has not previously been appreciated. Routine post-explant electronic evaluation has identified the defect in six implanted and one external pulse generator. The constant direct current in the implantable units, 0.14 to 0.26 milliamperes, is in the range that produces ventricular arrhythmias in dogs although this did not occur in our patients. Evidence of local myocardial damage existed in four cases and of electrode deterioration in three. The implant failures occurred without warning and in four cases within 2 weeks of demonstrated normal function, blunting the predictive benefits of pacemaker monitoring programs. Capacitor discharge circuits used in many pacers are inherently capable of developing direct current leakage in the event of output capacitor short circuit. In one model of pacemakers such continuous direct current leakage caused 8.3 percent (3 of 36) of pulse generator failures, widely scattered in time at 23, 27 and 46 months after implant. Capacitor short circuit causing constant direct current leakage can masquerade as primary battery failure and should be suspected when cessation of pacer function is associated with increased threshold or poor myocardial electrogram without evidence of wire break or displacement. PMID:1274862

  16. A fatal device-device interaction between a wearable automated defibrillator and a unipolar ventricular pacemaker.

    PubMed

    LaPage, Martin J; Canter, Charles E; Rhee, Edward K

    2008-07-01

    We report a fatal device-device interaction between a wearable automated defibrillator (WAD; LifeVest - LifeCor, Inc., Pittsburgh, PA, USA) and a unipolar pacemaker that occurred in an 18-year-old patient listed for cardiac transplantation due to his failing Fontan. The patient developed ventricular tachycardia that was initially detected by the WAD. However, large unipolar pacing artifacts and specific WAD arrhythmia detection algorithms caused the WAD to revert to nonrecognition of the arrhythmia, which lead to the patient's death. We identify likely causes of the failure and suggest methods of preventing such occurrences in the future. PMID:18684292

  17. Autonomic cardiac innervation

    PubMed Central

    Hasan, Wohaib

    2013-01-01

    Autonomic cardiac neurons have a common origin in the neural crest but undergo distinct developmental differentiation as they mature toward their adult phenotype. Progenitor cells respond to repulsive cues during migration, followed by differentiation cues from paracrine sources that promote neurochemistry and differentiation. When autonomic axons start to innervate cardiac tissue, neurotrophic factors from vascular tissue are essential for maintenance of neurons before they reach their targets, upon which target-derived trophic factors take over final maturation, synaptic strength and postnatal survival. Although target-derived neurotrophins have a central role to play in development, alternative sources of neurotrophins may also modulate innervation. Both developing and adult sympathetic neurons express proNGF, and adult parasympathetic cardiac ganglion neurons also synthesize and release NGF. The physiological function of these non-classical cardiac sources of neurotrophins remains to be determined, especially in relation to autocrine/paracrine sustenance during development. Cardiac autonomic nerves are closely spatially associated in cardiac plexuses, ganglia and pacemaker regions and so are sensitive to release of neurotransmitter, neuropeptides and trophic factors from adjacent nerves. As such, in many cardiac pathologies, it is an imbalance within the two arms of the autonomic system that is critical for disease progression. Although this crosstalk between sympathetic and parasympathetic nerves has been well established for adult nerves, it is unclear whether a degree of paracrine regulation occurs across the autonomic limbs during development. Aberrant nerve remodeling is a common occurrence in many adult cardiovascular pathologies, and the mechanisms regulating outgrowth or denervation are disparate. However, autonomic neurons display considerable plasticity in this regard with neurotrophins and inflammatory cytokines having a central regulatory function, including in possible neurotransmitter changes. Certainly, neurotrophins and cytokines regulate transcriptional factors in adult autonomic neurons that have vital differentiation roles in development. Particularly for parasympathetic cardiac ganglion neurons, additional examinations of developmental regulatory mechanisms will potentially aid in understanding attenuated parasympathetic function in a number of conditions, including heart failure. PMID:23872607

  18. CALCIUM-DRIVEN TRANSCRIPTION OF CARDIAC SPECIFYING GENE PROGRAM IN LIVER STEM CELLS

    EPA Science Inventory

    We have previously shown that a cloned liver stem cell line (WB F344) acquires a cardiac phenotype when seeded in a cardiac microenvironment in vivo and ex vivo. Here we investigated the mechanisms of this transdifferentiation in early (<72 hr) WB F344 cell, rat neonatal ventricu...

  19. Magnetic resonance imaging safety in pacemaker and implantable cardioverter defibrillator patients: how far have we come?

    PubMed Central

    Nordbeck, Peter; Ertl, Georg; Ritter, Oliver

    2015-01-01

    Magnetic resonance imaging (MRI) has long been regarded a general contraindication in patients with cardiovascular implanted electronic devices such as cardiac pacemakers or cardioverter defibrillators (ICDs) due to the risk of severe complications and even deaths caused by interactions of the magnetic resonance (MR) surrounding and the electric devices. Over the last decade, a better understanding of the underlying mechanisms responsible for such potentially life-threatening complications as well as technical advances have allowed an increasing number of pacemaker and ICD patients to safely undergo MRI. This review lists the key findings from basic research and clinical trials over the last 20 years, and discusses the impact on current day clinical practice. With ‘MR-conditional’ devices being the new standard of care, MRI in pacemaker and ICD patients has been adopted to clinical routine today. However, specific precautions and specifications of these devices should be carefully followed if possible, to avoid patient risks which might appear with new MR technology and further increasing indications and patient numbers. PMID:25796053

  20. Magnetic resonance imaging safety in pacemaker and implantable cardioverter defibrillator patients: how far have we come?

    PubMed

    Nordbeck, Peter; Ertl, Georg; Ritter, Oliver

    2015-06-21

    Magnetic resonance imaging (MRI) has long been regarded a general contraindication in patients with cardiovascular implanted electronic devices such as cardiac pacemakers or cardioverter defibrillators (ICDs) due to the risk of severe complications and even deaths caused by interactions of the magnetic resonance (MR) surrounding and the electric devices. Over the last decade, a better understanding of the underlying mechanisms responsible for such potentially life-threatening complications as well as technical advances have allowed an increasing number of pacemaker and ICD patients to safely undergo MRI. This review lists the key findings from basic research and clinical trials over the last 20 years, and discusses the impact on current day clinical practice. With 'MR-conditional' devices being the new standard of care, MRI in pacemaker and ICD patients has been adopted to clinical routine today. However, specific precautions and specifications of these devices should be carefully followed if possible, to avoid patient risks which might appear with new MR technology and further increasing indications and patient numbers. PMID:25796053

  1. Complete Atrial-Specific Knockout of Sodium-Calcium Exchange Eliminates Sinoatrial Node Pacemaker Activity

    PubMed Central

    Groenke, Sabine; Larson, Eric D.; Alber, Sarah; Zhang, Rui; Lamp, Scott T.; Ren, Xiaoyan; Nakano, Haruko; Jordan, Maria C.; Karagueuzian, Hrayr S.; Roos, Kenneth P.; Nakano, Atsushi; Proenza, Catherine; Philipson, Kenneth D.; Goldhaber, Joshua I.

    2013-01-01

    The origin of sinoatrial node (SAN) pacemaker activity in the heart is controversial. The leading candidates are diastolic depolarization by funny current (If) through HCN4 channels (the Membrane Clock hypothesis), depolarization by cardiac Na-Ca exchange (NCX1) in response to intracellular Ca cycling (the "Calcium Clock" hypothesis), and a combination of the two (Coupled Clock). To address this controversy, we used Cre/loxP technology to generate atrial-specific NCX1 KO mice. NCX1 protein was undetectable in KO atrial tissue, including the SAN. Surface ECG and intracardiac electrograms showed no atrial depolarization and a slow junctional escape rhythm in KO that responded appropriately to ?-adrenergic and muscarinic stimulation. Although KO atria were quiescent they could be stimulated by external pacing suggesting that electrical coupling between cells remained intact. Despite normal electrophysiological properties of If in isolated patch clamped KO SAN cells, pacemaker activity was absent. Recurring Ca sparks were present in all KO SAN cells, suggesting that Ca cycling persists but is uncoupled from the sarcolemma. We conclude that NCX1 is required for normal pacemaker activity in murine SAN. PMID:24278453

  2. Economics of cardiac adverse events after smallpox vaccination: lessons from the 2003 US Vaccination Program.

    PubMed

    Ortega-Sanchez, Ismael R; Sniadack, Mercedes M; Mootrey, Gina T

    2008-03-15

    Of >39,000 civilian public health responders vaccinated against smallpox in 2003, 203 reported cardiovascular adverse events (CAEs). An association exists between the US vaccinia strain and myocarditis and/or pericarditis ("myo/pericarditis" [MP]). Other associations are inconclusive. We used surveillance and follow-up survey data of CAE case patients to estimate the resources used during the 2003 smallpox vaccination program and used a probabilistic model to estimate the potential costs of CAEs in a mass vaccination campaign. For every million adult vaccinees, 3001 CAEs (including 351 MP cases) would occur, with >92% in revaccinees. CAEs would require a median of 5934 outpatient visits, 1786 emergency department visits, 533 days in general wards, 132 days in intensive care units, 5484 cardiac enzymes tests, 3504 electrocardiograms, 3049 chemistry tests, 2828 complete blood counts, and 1444 transthoracic echocardiograms, among other procedures. CAEs would reduce productivity (15,969 work days lost) and cost $11 per vaccinee. In a mass vaccination campaign, the care of a sizable number of CAEs would be resource intensive. PMID:18284356

  3. Cardiac Metastasis of Leiomyosarcoma Complicated with Complete Atrio-Ventricular Block and Ventricular Tachycardia

    PubMed Central

    Shin, Jae Ouk; Kim, Minsu; Kang, Woong Chol; Moon, Jeonggeun; Chung, Wook-Jin; Sung, Yon Mi

    2016-01-01

    We described a case of a 54-year-old male who presented with dizziness and dyspnea due to cardiac metastasis of leiomyosarcoma. Cardiac metastasis of leiomyosarcoma caused both bradyarrhythmia and tachyarrhythmia in the patient. He was treated with implantation of a permanent pacemaker for management of complete atrio-ventricular block and anti-arrhythmic drug that suppressed ventricular tachycardia successfully. PMID:27014358

  4. [Magnets, pacemaker and defibrillator: fatal attraction?].

    PubMed

    Bergamin, C; Graf, D

    2015-05-27

    This article aims at clarifying the effects of a clinical magnet on pacemakers and Implantable Cardioverter Defibrillators. The effects of electromagnetic interferences on such devices, including interferences linked to electrosurgery and magnetic resonance imaging are also discussed. In general, a magnet provokes a distinctive effect on a pacemaker by converting it into an asynchronous mode of pacing, and on an Implantable Cardioverter Defibrillator by suspending its own antitachyarythmia therapies without affecting the pacing. In the operating room, the magnet has to be used cautiously with precisely defined protocols which respect the type of the device used, the type of intervention planned, the presence or absence of EMI and the pacing-dependency of the patient. PMID:26182637

  5. [Reprogramming of a pacemaker induced by electrocautery].

    PubMed

    Caramella, J P; Mentre, B; Jattiot, F; Strouk, R; Deltang, D

    1987-01-01

    A case is reported of reprogramming of a ventricular unipolar permanent pacemaker induced by electrocautery during biliary surgery. After skin incision and use of the unipolar electrosurgery unit, the CPI model 505 multiprogrammable pulse generator previously set at 70 b X min-1 abruptly fired at 120 b X min-1. Application of a magnet over the pacemaker reduced the heart rate to 100 b X min-1. After surgery, the pulse generator was successfully reprogrammed to a rate of 65 b X min-1. Based on the analysis of this case and of previous reports, it is suggested, so as to avoid such complications, that the unipolar electrocautery be avoided when the surgical field is near the pulse generator or lead: that the bipolar electrocautery be preferred; that a magnet and non-invasive programmer be available during and after surgery; and that a postoperative assessment of the pulse generator be carried out. PMID:3619157

  6. New insights into pacemaker lead-induced venous occlusion: simulation-based investigation of alterations in venous biomechanics.

    PubMed

    Lonyai, Anna; Dubin, Anne M; Feinstein, Jeffrey A; Taylor, Charles A; Shadden, Shawn C

    2010-06-01

    Venous obstruction is a major complication of transvenous pacemaker placement. Despite the increasing use of pacemakers and implantable cardiac defibrillators, a lack of understanding remains with regard to risk factors for the development of device-associated venous obstruction. We hypothesize that computational fluid dynamics simulations can reveal prothrombogenic locations and define thrombosis risk based on patient-specific anatomies. Using anatomic data derived from computed tomography, computer models of the superior vena cava, subclavian, innominate, and internal jugular veins were constructed for three adult patients with transvenous pacemakers. These models were used to perform patient-specific simulations examining blood flow velocity, wall shear stress, and blood pressure, both with and without the presence of the pacing leads. To better quantify stasis, mean exposure time fields were computed from the venous blood flow data. In comparing simulations with leads to those without, evident increases in stasis at locations between the leads and along the surface of the vessels closest to the leads were found. These locations correspond to regions at known risk for thrombosis. This work presents a novel application of computational methods to study blood flow changes induced by pacemaker leads and possible complications such as venous occlusion and thrombosis. This methodology may add to our understanding of the development of lead-induced thrombosis and occlusion in the clinical arena, and enable the development of new strategies to avoid such complications. PMID:20514553

  7. Pacemaker lead erosion simulating "Loch Ness Monster": conservative management.

    PubMed

    Garg, Naveen; Moorthy, Nagaraja

    2012-12-01

    The majority of pacemaker pocket or lead erosions are due to either mechanical erosion by the bulky pulse generator or secondary to pacemaker pocket infection. We describe an unusual case of delayed pacemaker lead erosion causing extrusion of a portion of the pacing lead, with separate entry and exit points, with the gap filled with new skin formation, simulating the "Loch Ness Monster", which was successfully managed conservatively by surgical reinsertion. PMID:23284119

  8. Experience with Devices implanted fixed-rate pacemakers

    PubMed Central

    Siddons, Harold; Davies, Geoffrey

    1973-01-01

    The fate of 183 implants of Devices TF 2970 fixed-rate pacemakers is analysed. The incidence of clinical complications such as sepsis or skin necrosis, displacement of the electrode, and exit block, and the causes of the 19 deaths are discussed. In 28 of the 183 pacemakers pacing stopped for technical reasons, which are described; the commonest cause of failure was the batteries. The incidence of pacemaker failure has been estimated statistically from a much larger series of 558 implants. PMID:4731109

  9. Software Simulation of an Implantable Pacemaker

    PubMed Central

    Riley, R. E.; Rossing, M. A.

    1983-01-01

    Software simulation of a hardware system has been used as an effective tool in evaluating and testing software for microprocessor-based control systems. This paper reports on a system simulator used in the development and testing of software for an implantable pacemaker. The paper describes the functional and structural characteristics of the simulator, the user interface, run-time information that is provided from a simulation, and experiences with the system simulator.

  10. Pediatric cardiac emergencies.

    PubMed

    Lee, C; Mason, L J

    2001-06-01

    Successful management of pediatric cardiac emergencies requires an accurate diagnosis to institute an appropriate plan of therapy. The diagnosis, however, is not always straightforward, as evidenced by the nonspecific clinical picture that can be presented by congenital heart defects. Entertaining the possibility of a cardiac problem in neonates with pulmonary symptoms unresponsive to standard therapies is crucial for successful management of patients with congenital heart disease. In addition to ventilatory support, prostaglandin E1 infusions or emergency interventional cardiac catheterization is often a life-saving initial measure in patients with acutely decompensated congenital cardiac lesions that require a patent ductus arteriosus for survival. Pericardial tamponade is associated with various acquired and iatrogenic causes. Emergent pericardiocentesis is mandatory when cardiovascular compromise occurs. The goal of anesthetic management is to maintain cardiac output. With the increasing use of central venous catheters in neonatal ICUs and the high mortality rate for central venous catheter-related cardiac tamponade, the diagnosis must be considered in any patient with a central venous catheter in situ who acutely develops unexplained hypotension, bradycardia, and diminished pulses. Arrhythmias also can cause hemodynamic instability in infants and children. Supraventricular tachycardia is by far the most common emergently presenting arrhythmia in the pediatric population. Unstable patients require immediate intravenous adenosine or synchronized cardioversion. Complete heart block is rare, but it can lead to congestive heart failure and occasionally to cardiovascular collapse and sudden death. Emergency treatment of complete heart block includes pharmacologic support and temporary or permanent pacemaker placement as indicated. In infants, congestive heart failure usually is related to congenital heart disease, whereas in older children, it tends to be secondary to an acquired cause. Supportive measures, fluid restriction, and inotropic support are the principles of initial treatment. Prompt recognition and initiation of appropriate therapy in pediatric cardiac emergencies are essential for favorable outcomes. PMID:11469066

  11. Permanent pacemaker malfunction: diagnostic aspects of temporary pacing.

    PubMed Central

    Berman, N D

    1980-01-01

    A temporary pacing electrode can function as a diagnostic as well as a therapeutic tool. This is illustrated in two patients whose permanent pacemakers unexpectedly failed. In the first patient a demand pacemaker was inhibited by a magnet rather than converting to the asynchronous mode. In the second the pacemaker appeared to be producing low-voltage potentials not detectable on the surface electrocardiogram. The presence of a temporary pacing electrode can be useful for defining the cause of pacemaker failure and the nature of any associated arrhythmias. Images FIG. 1 FIG. 3 PMID:7260759

  12. [Pacemaker ECG quiz no. 24. Implanted the wrong device?].

    PubMed

    Israel, C W

    2011-03-01

    In a 73-year-old patient, a loop recorder was implanted for syncope of unknown origin which allowed the diagnosis of sinus node disease with sinus bradycardia and sinus arrest. At implantation of a dual-chamber pacemaker, the loop recorder was not explanted. During a pacemaker check-up visit a few months later, the patient complained about slight dizziness together with palpitations. While the interrogation of pacemaker memory did not provide any significant information, the loop recorder had stored several arrhythmias. This case demonstrates that it may be useful not to explant a loop recorder at the time of pacemaker implantation. PMID:21424406

  13. Complicated Holter tracing with an incidence of inappropriate mode switch due to sensing abnormalities in a patient with dual-chamber pacemaker.

    PubMed

    Por?ba, Ma?gorzata; Karczmarewicz, Stefan; Szwarc, Bart?omiej; Sobieszcza?ska, Ma?gorzata; Wranicz, Jerzy Krzysztof

    2011-01-01

    24-hour Holter monitoring of a 59 year-old man with DDDR pacemaker (programmed mode: DDD) implanted for sick sinus syndrome with paroxysmal atrial fibrillation was performed one month after implantation, due to palpitations. Several episodes of rapid pacing of decreasing rate were detected. Intracardiac recording stored in the pacemaker memory had shown episodes of atrial lead oversensing, which led to the mode switch, resulting in DDIR mode. Signals which caused oversensing were not seen in Holter tracing. PMID:21305495

  14. Executive functions improvement following a 5-month aquaerobics program in older adults: Role of cardiac vagal control in inhibition performance.

    PubMed

    Albinet, Cédric T; Abou-Dest, Amira; André, Nathalie; Audiffren, Michel

    2016-03-01

    The aims of this study were to examine the effects of aerobic exercise on measures of executive performance and their relationships with changes in cardiorespiratory fitness, cardiac vagal control (heart rate variability) and psychological variables. Thirty-six sedentary seniors aged 60-75 years were randomly assigned to a swimming and aquaerobics program or a stretching program two times a week for 21 weeks. Executive functions (inhibition, updating of working memory and cognitive flexibility) and cardiorespiratory fitness (estimated VO2max) were assessed at the start, after 10 weeks of program and at the end of the program. Resting HRV and measures of psychological outcomes (depression, self-efficacy, decisional balance) were obtained at the start and at the end of the program. Participants of both groups significantly improved their VO2max level, their psychological state and their performance for the 2-back task. Only the participants in the aquaerobics group significantly improved their vagally-mediated HRV and their performance for the Stroop test and the verbal running-span test at the end of the program. Only improvements in cardiac vagal control and in inhibition were shown to be functionally related. These results are discussed in line with the model of neurovisceral integration. PMID:26812613

  15. Heart rate lowering by inhibition of the pacemaker current: a new therapeutic perspective in cardiovascular disease.

    PubMed

    Dilaveris, Polychronis; Giannopoulos, Georgios; Synetos, Andreas; Gatzoulis, Konstantinos; Stefanadis, Christodoulos

    2006-10-01

    Several studies have demonstrated that resting heart rate is an important correlate of cardiovascular and all-cause mortality and that the mortality benefit of some cardiovascular drugs seems to be related in part to their heart rate-lowering effects. Since the currently available classes of drugs with heart-rate lowering effect (e.g. beta-blockers and calcium channel antagonists) also exert multiple structural and functional actions on the cardiovascular system, which may be in some cases undesired, the introduction of a new class of agents exclusively affecting the pacemaker activity of the sinus node is of particular interest. The first molecule of this class - sinus node modulators or I(f)-current inhibitors - to reach clinical application is ivabradine. Cardiac pacemaker cells generate a spontaneous slow diastolic depolarisation that drives the membrane voltage away from a hyperpolarised level towards the threshold level for initiating a subsequent action potential, generating rhythmic action potentials that propagate through the heart and trigger myocardial contraction. The I(f) current is an inward ionic current that determines the slope of diastolic depolarisation, which in turn controls the heart beating rate. Extensive work has amply demonstrated its involvement in the generation of spontaneous activity. The molecular basis of the generation of the pacemaker current was landmarked by the cloning of hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels, which constitute the structural units of the f-channels. This review addresses the major basic properties of cardiac f-channels, with a focus on the mode of action of I(f)-current inhibitors and outlines the therapeutic implications of the existing research data. PMID:17073608

  16. Pacemaker therapy in isolated congenital complete atrioventricular block.

    PubMed

    Breur, Johannes M P J; Udink Ten Cate, Floris E A; Kapusta, Livia; Cohen, Mitchell I; Crosson, Jane E; Boramanand, Nicole; Lubbers, Louise J; Friedman, Alan H; Brenner, Joel I; Vetter, Victoria L; Sreeram, Narayanswami; Meijboom, Erik J

    2002-12-01

    The aim of this study was to evaluate the effect of pacemaker (PM) therapy in patients with isolated congenital complete atrioventricular block (CCAVB). Patients with CCAVB eventually quality for PM implantation, however, timing remains controversial. Retrospective evaluation of left ventricular end-diastolic diameter (LVEDD), shortening fraction (SF), and cardiothoracic ratio (CTR) in 149 CCAVB patients, before, at, and after PM implantation was carried out. LVEDD shows an average increase of 0.48%/month in non-PM patients, and an average decrease of 0.88%/month in PM patients. SF shows an average increase of 0.10%/month in non-PM, and an average decrease of 0.32%/month in PM patients. CTR shows an average increase of 0.02%/month in non-PM, and an average decrease of 0.19%/month in PM patients. The difference between the non-PM and PM groups is significant (P = 0.05) for all variables. Symptomatic patients show no significant change in LVEDD after PM therapy (from 66.5% before to 68.5% after PM therapy). Asymptomatic patients do show a significant (P < 0.001) decrease in LVEDD after PM therapy (from 78.4% before to 73.3% after PM therapy). CTR does not differ significantly between symptomatic and asymptomatic patients before PM therapy (58% and 57%, respectively). CTR does differ significantly (P < 0.001) between symptomatic and asymptomatic patients after PM therapy (52% and 48%, respectively). Heart size and SF are increased in most patients with isolated CCAVB. PM implantation is associated with a decrease in heart size and normalization of SF in most patients. Indications for PM therapy in children may require reevaluation in asymptomatic patients with increased cardiac size and decreased cardiac function. PMID:12520668

  17. T-wave inversion: cardiac memory or myocardial ischemia?

    PubMed

    Chen-Scarabelli, Carol; Scarabelli, Tiziano M

    2009-09-01

    This article presents a case report of a 74-year-old man with T-wave inversion (TwI) in atrial fibrillation noted during routine pacemaker interrogation. The patient was seen for routine pacemaker interrogation, at which time he was noted to have underlying atrial fibrillation. A12-lead electrocardiogram of the atrial fibrillation revealed significant TwIs. He was subsequently worked up for myocardial ischemia and was found to have a moderate-sized,moderate-degree inferior wall myocardial perfusion defect. He was subsequently referred for a cardiac catheterization. The cardiac catheterization revealed nonobstructive coronary artery disease. The follow-up electrocardiogram revealed persistent but attenuated TwI.The TwIs were attributed to cardiac memory, a common but infrequently recognized phenomenon of which many clinical practitioners are unaware. Cardiac memory is due to the T wave tracking the preceding abnormal QRS complex and can be induced by right ventricular pacing or arrhythmias. PMID:19683128

  18. Stochastic Aspects of Cardiac Arrhythmias

    NASA Astrophysics Data System (ADS)

    Lerma, Claudia; Krogh-Madsen, Trine; Guevara, Michael; Glass, Leon

    2007-07-01

    Abnormal cardiac rhythms (cardiac arrhythmias) often display complex changes over time that can have a random or haphazard appearance. Mathematically, these changes can on occasion be identified with bifurcations in difference or differential equation models of the arrhythmias. One source for the variability of these rhythms is the fluctuating environment. However, in the neighborhood of bifurcation points, the fluctuations induced by the stochastic opening and closing of individual ion channels in the cell membrane, which results in membrane noise, may lead to randomness in the observed dynamics. To illustrate this, we consider the effects of stochastic properties of ion channels on the resetting of pacemaker oscillations and on the generation of early afterdepolarizations. The comparison of the statistical properties of long records showing arrhythmias with the predictions from theoretical models should help in the identification of different mechanisms underlying cardiac arrhythmias.

  19. Quantification of fiber orientation in the canine atrial pacemaker complex using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Ambrosi, Christina M.; Fedorov, Vadim V.; Schuessler, Richard B.; Rollins, Andrew M.; Efimov, Igor R.

    2012-07-01

    The atrial pacemaker complex is responsible for the initiation and early propagation of cardiac impulses. Optical coherence tomography (OCT), a nondestructive imaging modality with spatial resolutions of ˜1 to 15 μm, can be used to identify unique fiber orientation patterns in this region of the heart. Functionally characterized canine sinoatrial nodes (SAN) (n=7) were imaged using OCT up to ˜1 mm below the endocardial tissue surface. OCT images were directly compared to their corresponding histological sections. Fiber orientation patterns unique to the crista terminalis (CT), SAN, and surrounding atrial myocardium were identified with dominant average fiber angles of 89±12 deg, 110±16 deg, and 95±35 deg, respectively. Both the CT and surrounding atrial myocardium displayed predominantly unidirectionally based fiber orientation patterns within each specimen, whereas the SAN displayed an increased amount of fiber disarray manifested quantitatively as a significantly greater standard deviation in fiber angle distribution within specimens [33±7 deg versus 23±5 deg, atrium (p=0.02); 18±3 deg, CT (p=0.0003)]. We also identified unique, local patterns of fiber orientation specific to the functionally characterized block zone. We demonstrate the ability of OCT in detecting components of the atrial pacemaker complex which are intimately involved in both normal and abnormal cardiac conduction.

  20. Emotion and cardiac technology: an interpretive study.

    PubMed

    Anderson, Carole; Moyle, Wendy; McAllister, Margaret

    This paper presents a frequently overlooked aspect of advanced technological care--that of the human dimension and emotions. Emotionality is defined as the emotional ways that a client experiences their embodied experience as a recipient of a cardiac pacemaker. One individual's story from a larger interpretive study of clients who received pacemakers is presented and interpreted. Kev's story encapsulates the difficulties of dealing with and understanding cardiac technology. When Kev's heart malfunctions he confronts a new reality; an experience where the 'technological body' is linked confusingly with emotion. This complex interplay between technology, the body and emotionality is discussed to demonstrate the importance of the mediating role that nurses can and should play in clients' adaptation and recovery. PMID:12537150

  1. Dual chamber pacemaker therapy for mid-cavity obstructive hypertrophic cardiomyopathy.

    PubMed

    Begley, D; Mohiddin, S; Fananapazir, L

    2001-11-01

    Intracavitary LV obstruction is an important determinant of clinical outcome in hypertrophic cardiomyopathy (HCM). In a minority of patients the obstruction is at the level of the papillary muscles. Mid-cavity obstructive HCM may be associated with a distal LV aneurysm and a worse prognosis. It is often not amenable to standard cardiac surgeryfor LV outflow obstruction. The long-term effects (mean follow-up 4.8+/-2.9 years) of dual chamber (DDD) pacemaker therapy in 14 patients with mid-cavity obstructive HCM (mean age 34+/-16 years, range 15-65 years) were studied. Patients were evaluated by cardiac catheterization at baseline and 6 months to 1 year after receiving DDD pacemakers off all drug therapy. Symptoms were improved in all patients and NYHA functional class reduced from 2.8+/-0.1 to 1.9+/-0.4 (P < 0.0005). Intracavitary LV pressure gradients was reduced significantly (43+/-36 vs 84+/-31 mmHg at baseline, P < 0.0005). There was a significant associated reduction in apical LV systolic pressure (152+/-37 vs 188+/-34 mmHg, P < 0.001). In addition, there was a trend towards increased exercise tolerance (445+/-123 vs 396+/-165). Cardiac output and LV filling pressures were unchanged. In conclusion, chronic DDD pacing results in significant symptomatic and hemodynamic improvement in this uncommon but important subset of patients with obstructive HCM in whom the role of cardiac surgery is less well defined compared with the more typical outflow tract location of LV obstruction. PMID:11816633

  2. Peak Oxygen Uptake after Cardiac Rehabilitation: A Randomized Controlled Trial of a 12-Month Maintenance Program versus Usual Care

    PubMed Central

    Madssen, Erik; Arbo, Ingerid; Granien, Ingrid; Walderhaug, Liv; Moholdt, Trine

    2014-01-01

    Background Exercise capacity is a strong predictor of survival in patients with coronary artery disease (CAD). Exercise capacity improves after cardiac rehabilitation exercise training, but previous studies have demonstrated a decline in peak oxygen uptake after ending a formal rehabilitation program. There is a lack of knowledge on how long-term exercise adherence can be achieved in CAD patients. We therefore assessed if a 12-month maintenance program following cardiac rehabilitation would lead to increased adherence to exercise and increased exercise capacity compared to usual care. Materials and Methods Two-centre, open, parallel randomized controlled trial with 12 months follow-up comparing usual care to a maintenance program. The maintenance program consisted of one monthly supervised high intensity interval training session, a written exercise program and exercise diary, and a maximum exercise test every third month during follow-up. Forty-nine patients (15 women) on optimal medical treatment were included following discharge from cardiac rehabilitation. The primary endpoint was change in peak oxygen uptake at follow-up; secondary endpoints were physical activity level, quality of life and blood markers of cardiovascular risk. Results There was no change in peak oxygen uptake from baseline to follow-up in either group (intervention group 27.9 (4.7) to 28.8 (5.6) mLkg (-1) min (?1), control group 32.0 (6.2) to 32.8 (5.8) mLkg (?1) min (?1), with no between-group difference, p?=?0.22). Quality of life and blood biomarkers remained essentially unchanged, and both self-reported and measured physical activity levels were similar between groups after 12 months. Conclusions A maintenance exercise program for 12 months did not improve adherence to exercise or peak oxygen uptake in CAD patients after discharge from cardiac rehabilitation compared to usual care. This suggests that infrequent supervised high intensity interval training sessions are inadequate to improve peak oxygen uptake in this patient group. Trial Registration ClinicalTrials.gov NCT01246570 PMID:25247991

  3. Nonlinear dynamics, chaos and complex cardiac arrhythmias

    NASA Technical Reports Server (NTRS)

    Glass, L.; Courtemanche, M.; Shrier, A.; Goldberger, A. L.

    1987-01-01

    Periodic stimulation of a nonlinear cardiac oscillator in vitro gives rise to complex dynamics that is well described by one-dimensional finite difference equations. As stimulation parameters are varied, a large number of different phase-locked and chaotic rhythms is observed. Similar rhythms can be observed in the intact human heart when there is interaction between two pacemaker sites. Simplified models are analyzed, which show some correspondence to clinical observations.

  4. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker lead adaptor. 870.3620 Section 870.3620 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead...

  5. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pacemaker lead adaptor. 870.3620 Section 870.3620 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead...

  6. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pacemaker lead adaptor. 870.3620 Section 870.3620 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead...

  7. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870.3650 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker...

  8. 21 CFR 870.3690 - Pacemaker test magnet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pacemaker test magnet. 870.3690 Section 870.3690 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3690 Pacemaker test...

  9. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870.3650 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker...

  10. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870.3650 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker...

  11. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870.3650 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker...

  12. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pacemaker lead adaptor. 870.3620 Section 870.3620 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead...

  13. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870.3650 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker...

  14. 21 CFR 870.3730 - Pacemaker service tools.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pacemaker service tools. 870.3730 Section 870.3730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3730 Pacemaker...

  15. 21 CFR 870.3690 - Pacemaker test magnet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pacemaker test magnet. 870.3690 Section 870.3690 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3690 Pacemaker test...

  16. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pacemaker lead adaptor. 870.3620 Section 870.3620 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead...

  17. 21 CFR 870.3730 - Pacemaker service tools.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pacemaker service tools. 870.3730 Section 870.3730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3730 Pacemaker...

  18. 21 CFR 870.3690 - Pacemaker test magnet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pacemaker test magnet. 870.3690 Section 870.3690 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3690 Pacemaker test...

  19. Runaway pacemaker: a still existing complication and therapeutic guidelines.

    PubMed

    Mickley, H; Andersen, C; Nielsen, L H

    1989-07-01

    Runaway pacemaker is a rare, but still existing potential lethal complication in permanent pacemakers. Within 4 1/2 years, we saw two cases of runaway pacemaker in patients with multiprogrammable, VVI pacemakers (Siemens-Elema, Model 668). In both cases a pacemaker-induced ventricular tachycardia (rate 240-260 beats/min) was documented. One patient died. Runaway pacemakers must be exchanged as soon as possible. Until this can be accomplished, different emergency maneuvers should be tried. As documented in the cases presented, placing a magnet over the pacemaker may result in a lower, more physiological pacing rate. Reprogramming the pulse generator to a lower output or the use of external chest wall overdrive stimulation may also be successful, but these procedures require the presence of an adequate escape rhythm. If this is not the case or the former maneuvers have failed, an external pacemaker may be connected to the permanent pacing lead. Thereafter, the lead can be safely cut. As an alternative, a temporary transvenous pacing lead may be established prior to disconnecting the permanent pacing lead. PMID:2743631

  20. Laser welding in the manufacture of heart pacemakers

    NASA Astrophysics Data System (ADS)

    Janssen, G. W. G.

    Laser welding has become a key process in the manufacture of pacemakers but there are more powerful arguments than that for the use of lasers: (1) The laser is a most refined welding tool; (2) The laser simplifies pacemaker design; and (3) Laser welding is readily adapted to CNC control.

  1. Electrocution induced symptomatic bradycardia necessitating pacemaker implantation.

    PubMed

    Yew, Kuan Leong

    2014-04-01

    Electrical or electrocution injury is a common accidental occurrence and mostly workplace related. Fatal arrhythmias, skin injury and sudden death may ensue. However, it is rare for electrocution to result in permanent low rate sinus bradycardia, incompatible with an active lifestyle. The probable mechanisms for this pathological sinus bradycardia are sinus node dysfunction and autonomic dysfunction with vagal predominance. We describe a young patient who suffered a non fatal electrocution with resultant low rate sinus bradycardia and its successful treatment with a dual chamber rate responsive pacemaker. PMID:25104983

  2. Electrocution Induced Symptomatic Bradycardia Necessitating Pacemaker Implantation

    PubMed Central

    Yew, Kuan Leong

    2014-01-01

    Electrical or electrocution injury is a common accidental occurrence and mostly workplace related. Fatal arrhythmias, skin injury and sudden death may ensue. However, it is rare for electrocution to result in permanent low rate sinus bradycardia, incompatible with an active lifestyle. The probable mechanisms for this pathological sinus bradycardia are sinus node dysfunction and autonomic dysfunction with vagal predominance. We describe a young patient who suffered a non fatal electrocution with resultant low rate sinus bradycardia and its successful treatment with a dual chamber rate responsive pacemaker. PMID:25104983

  3. Asynchronous response of coupled pacemaker neurons.

    PubMed

    Dodla, Ramana; Wilson, Charles J

    2009-02-13

    We study a network model of two conductance-based pacemaker neurons of differing natural frequency, coupled with either mutual excitation or inhibition, and receiving shared random inhibitory synaptic input. The networks may phase lock spike to spike for strong mutual coupling. But the shared input can desynchronize the locked spike pairs by selectively eliminating the lagging spike or modulating its timing with respect to the leading spike depending on their separation time window. Such loss of synchrony is also found in a large network of sparsely coupled heterogeneous spiking neurons receiving shared input. PMID:19257636

  4. Asynchronous response of coupled pacemaker neurons

    PubMed Central

    Dodla, Ramana; Wilson, Charles J.

    2009-01-01

    We study a network model of two conductance-based pacemaker neurons of differing natural frequency, coupled with either mutual excitation or inhibition, and receiving shared random inhibitory synaptic input. The networks may phase-lock spike-to-spike for strong mutual coupling. But the shared input can desynchronize the locked spike-pairs by selectively eliminating the lagging spike or modulating its timing with respect to the leading spike depending on their separation time window. Such loss of synchrony is also found in a large network of sparsely coupled heterogeneous spiking neurons receiving shared input. PMID:19257636

  5. The effect of the cardiac rehabilitation program on obese and non-obese females with coronary heart disease

    PubMed Central

    Ghashghaei, Fatemeh Esteki; Sadeghi, Masoumeh; Mostafavi, Samaneh; Heidari, Hossein; Sarrafzadegan, Nazal

    2012-01-01

    Introduction: Obesity is strongly associated with coronary heart disease and it is known as an independent risk factor. So, the aim of this study was to investigate the effects of phase II comprehensive cardiac rehabilitation program on obesity indexes, functional capacity, lipid profiles, and fasting blood sugar in obese and non-obese female patients with coronary heart disease and to compare changes in these groups. Materials and Methods: Two hundred and five women with coronary heart disease participated in our study. At the beginning of study, body mass index, functional capacity, and lipid profiles and fasting blood sugar were evaluated; then, these patients were divided into two groups, patients who had BMI?30 were known as obese and who had BMI<30 were known as non-obese patients. All of them completed the period of cardiac rehabilitation program, and 2 months later, all risk factors were examined for the second time in each group. Data were analyzed with SPSS software version 15. For comparing the mean of outcomes, independent t-tests and paired t-tests were used. Results: Data revealed that unless in weight (P=0.00) and functional capacity (P=0.001), there were no significant differences in obese and non-obese female patients, at baseline. As a result of the cardiac rehabilitation program, both groups had significant improvement in functional capacity (P=0.00), weight reduction (P=0.00), triglyceride (P=0.01 and P=0.02, respectively), low-density lipoprotein cholesterol (P=0.01), and low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio (P=0.00 and P=0.003, respectively). As well, significant improvement was observed in high-density lipoprotein (P=0.01) only in obese female, and non-obese female had significant differences in total cholesterol (P=0.003). However, there were not significant changes in total cholesterol (P=0.05) and fasting blood sugar (P=0.09) in obese female. Also, non-obese females didnt have favorable differences in high-density lipoprotein cholesterol (P=0.23) and fasting blood sugar (P=0.13). In addition, comparing two groups didnt show any significant differences in each risk factors except BMI (P=0.03). Conclusion: Our study revealed that comprehensive cardiac rehabilitation program results in significant improvement in cardiovascular risk factors and functional capacity at all levels of BMI in female with coronary heart disease. PMID:23210076

  6. Drug overdoses requiring temporary cardiac pacing; a study of six cases treated at Altnagelvin Hospital, Londonderry.

    PubMed Central

    McGlinchey, P. G.; McNeill, A. J.

    1998-01-01

    Drug overdoses in general are increasing and overdoses of cardiac medications are also increasing; some are associated with a high mortality. Temporary cardiac pacing has a valuable role in cases of hypotension related to dysrhythmia, or when it is necessary to provide overdrive pacing. However, despite technically successful and uncomplicated pacemaker insertion and restoration of cardiac electrical activity, patients developing bradyarrhythmia and hypotension after an overdose are in a high risk group. PMID:9652193

  7. Correlation between changes in diastolic dysfunction and health-related quality of life after cardiac rehabilitation program in dilated cardiomyopathy

    PubMed Central

    Mehani, Sherin H.M.

    2012-01-01

    Chronic heart failure (CHF) is a complex syndrome characterized by progressive decline in left ventricular function, low exercise tolerance and raised mortality and morbidity. Left ventricular diastolic dysfunction plays a major role in CHF and progression of most cardiac diseases. The current recommended goals can theoretically be accomplished via exercise and pharmacological therapy so the aim of the present study was to evaluate the impact of cardiac rehabilitation program on diastolic dysfunction and health related quality of life and to determine the correlation between changes in left ventricular diastolic dysfunction and domains of health-related quality of life (HRQoL). Forty patients with chronic heart failure were diagnosed as having dilated cardiomyopathy (DCM) with systolic and diastolic dysfunction. The patients were equally and randomly divided into training and control groups. Only 30 of them completed the study duration. The training group participated in rehabilitation program in the form of circuit-interval aerobic training adjusted according to 5580% of heart rate reserve for a period of 7months. Circuit training improved both diastolic and systolic dysfunction in the training group. On the other hand, only a significant correlation was found between improvement in diastolic dysfunction and health related quality of life measured by Kansas City Cardiomyopathy Questionnaire. It was concluded that improvement in diastolic dysfunction as a result of rehabilitation program is one of the important underlying mechanisms responsible for improvement in health-related quality of life in DCM patients. PMID:25685417

  8. [Pacemaker and implantable defibrillators with telemedical support].

    PubMed

    Mller, A; Helms, T M; Neuzner, J; Schweizer, J; Korb, H

    2009-03-01

    Recent developments in pacemaker and ICD therapy can be characterized by a rising number of implantations (especially in the field of ICD and CRT systems) and an increasing complexity of the units involved. Problems evolving from this trend are the soaring numbers of necessary follow-up examinations, issues of patient safety and the necessity of device management by specialized physicians. Telemonitoring offers various possibilities of improvement in these areas. The manufacturers of the devices have developed applicable solutions for concepts of care including telemedical monitoring of patients with pacemakers, ICD and CRT systems. The systems commonly include an implant capable of either automatic or manual data transmission, a device for transmitting the implant's data (mobile communication or fixed line network), a server managing the information and a front-end (internet-based) platform for the physician. Multiple clinical trials have verified the stability and the security of this method of data transmission. Telemedical monitoring can be used in order to improve the monitoring of the patients' state of health (e. g., patients with CRT systems because of their CHF) and the management of arrhythmias (e. g., patients suffering from paroxysmal atrial fibrillation). Telemonitoring allows the intervals between follow-up check-ups to be individualized, thus, leading to financial savings. The telemedical monitoring of patients with ICD and CRT systems facilitates new opportunities for networked follow-up care and comprehensive medical treatment. PMID:19259635

  9. Cardiac Implantable Electronic Device Implantation: Intraoperative, Acute, and Remote Complications.

    PubMed

    Harding, Melissa E

    2015-01-01

    Implantation of cardiac implantable electronic devices (CIEDs), including pacemakers, implantable cardioverter-defibrillators, and biventricular pacemakers/cardioverter-defibrillators, is becoming increasingly common with new implants now exceeding 1.5 million per year globally. As a result, health care providers in all disciplines are caring for an increasing number of patients with CIEDs. Although the risk of complications associated with implantation of CIEDs is relatively low, the sequela can be catastrophic. Management requires an understanding of an individual patient's indication for CIED implant, the steps of implant procedures, device function, and natural history of each complication. PMID:26484991

  10. Evaluation of a Standardized Patient Education Program for Inpatient Cardiac Rehabilitation: Impact on Illness Knowledge and Self-Management Behaviors up to 1 Year

    ERIC Educational Resources Information Center

    Meng, Karin; Seekatz, Bettina; Haug, Gnter; Mosler, Gabriele; Schwaab, Bernhard; Worringen, Ulrike; Faller, Hermann

    2014-01-01

    Patient education is an essential part of the treatment of coronary heart disease in cardiac rehabilitation. In Germany, no standardized and evaluated patient education programs for coronary heart disease have been available so far. In this article, we report the evaluation of a patient-oriented program. A multicenter quasi-experimental,

  11. Evaluation of a Standardized Patient Education Program for Inpatient Cardiac Rehabilitation: Impact on Illness Knowledge and Self-Management Behaviors up to 1 Year

    ERIC Educational Resources Information Center

    Meng, Karin; Seekatz, Bettina; Haug, Günter; Mosler, Gabriele; Schwaab, Bernhard; Worringen, Ulrike; Faller, Hermann

    2014-01-01

    Patient education is an essential part of the treatment of coronary heart disease in cardiac rehabilitation. In Germany, no standardized and evaluated patient education programs for coronary heart disease have been available so far. In this article, we report the evaluation of a patient-oriented program. A multicenter quasi-experimental,…

  12. Cardiac fluid dynamics anticipates heart adaptation.

    PubMed

    Pedrizzetti, Gianni; Martiniello, Alfonso R; Bianchi, Valter; D'Onofrio, Antonio; Caso, Pio; Tonti, Giovanni

    2015-01-21

    Hemodynamic forces represent an epigenetic factor during heart development and are supposed to influence the pathology of the grown heart. Cardiac blood motion is characterized by a vortical dynamics, and it is common belief that the cardiac vortex has a role in disease progressions or regression. Here we provide a preliminary demonstration about the relevance of maladaptive intra-cardiac vortex dynamics in the geometrical adaptation of the dysfunctional heart. We employed an in vivo model of patients who present a stable normal heart function in virtue of the cardiac resynchronization therapy (CRT, bi-ventricular pace-maker) and who are expected to develop left ventricle remodeling if pace-maker was switched off. Intra-ventricular fluid dynamics is analyzed by echocardiography (Echo-PIV). Under normal conditions, the flow presents a longitudinal alignment of the intraventricular hemodynamic forces. When pacing is temporarily switched off, flow forces develop a misalignment hammering onto lateral walls, despite no other electro-mechanical change is noticed. Hemodynamic forces result to be the first event that evokes a physiological activity anticipating cardiac changes and could help in the prediction of longer term heart adaptations. PMID:25529139

  13. Feasibility of using the automatic generating system for quartz watches as a leadless pacemaker power source.

    PubMed

    Goto, H; Sugiura, T; Harada, Y; Kazui, T

    1999-05-01

    An automatic power-generating system (AGS) which converts kinetic energy into electric energy for quartz watches was tested as a power source for implantable cardiac pacemakers. An automatic power-generating mechanism and a capacitor (0.33 F) were removed from a quartz watch (SEIKO) and encapsulated in a polyvinyl case. Characteristics of the AGS were investigated by acceleration equipment. The capacitor in the AGS was charged to 2.0 V (0.66 J) by placing it on the equipment for about 30 minutes. The equipment has a 2 Hz cycle and generates +/- 1.7 G at the end of each half cycle. The AGS (fully charged to 2.0 V) was used as the power source for a pulse generator circuit built using commercially available CMOS IC. The circuit generated pulses of 0.5 ms width at 1 Hz (60 pulses min-1). The voltage of the AGS was maintained at 1.6 V while it was being charged by the accelerations. The generator supplied pulses of 0.75 V, 1.47 mA through a 510 omega load. With fully charged AGS, the generator was also used to pace a mongrel dog's heart at 140 beats min-1 for 60 minutes. During pacing, the AGS supplied 420 mJ to the circuit and the cardiac muscle. The AGS was placed on the right ventricular wall of the mongrel dog under anaesthesia. Energy of 80 mJ is stored in a capacitor by the heart beating at about 200 beats/min for 30 minutes. Thus the AGS generated 13 microJ per heart beat. This result suggests that the AGS may supply enough energy for use in a cardiac pacemaker. PMID:10505390

  14. Cardiovascular patients’ experiences of living with pacemaker: Qualitative study

    PubMed Central

    Ghojazadeh, Morteza; Azami-Aghdash, Saber; Sohrab-Navi, Zahra; Kolahdouzan, Kasra

    2015-01-01

    BACKGROUND A pacemaker implantation is considered major life event for cardiovascular patients, so they will probably have very interesting experiences of living with this device. The aim of this study was to explore the experiences of cardiovascular patients living with the pacemaker. METHODS In this qualitative study, 27 patients were chosen through purposive sampling to achieve data saturation, and their experiences were examined using semi-structured interviews. The patients’ statements were recorded with their consent and analyzed using content analysis method. RESULTS Participants’ experiences included three main themes: “Problems and limitations,” “feeling and dealing with pacemaker”, and “sources of comfort” and 10 sub-themes including: physical problems, financial problems, social problems, the first encounter, the feeling of living with the pacemaker, how to cope with pacemaker, satisfaction with pacemaker, good family support, hospital and hospital staff performance, and role of religious beliefs. CONCLUSION Planning to solve social problems, identifying and changing feelings of patients using pacemakers, reinforcing the resources of comfort especially family support seem to be necessary steps for improving quality of life and impact of using pacemaker. PMID:26715933

  15. Firing Patterns and Transitions in Coupled Neurons Controlled by a Pacemaker

    NASA Astrophysics Data System (ADS)

    Li, Mei-Sheng; Lu, Qi-Shao; Duan, Li-Xia; Wang, Qing-Yun

    2008-08-01

    To reveal the dynamics of neuronal networks with pacemakers, the firing patterns and their transitions are investigated in a ring HR neuronal network with gap junctions under the control of a pacemaker. Compared with the situation without pacemaker, the neurons in the network can exhibit various firing patterns as the external current is applied or the coupling strength of pacemaker varies. The results are beneficial for understanding the complex cooperative behaviour of large neural assemblies with pacemaker control.

  16. If and SR Ca2+ release both contribute to pacemaker activity in canine sinoatrial node cells

    PubMed Central

    Gao, Zhan; Chen, Biyi; Joiner, Mei-ling A.; Wu, Yuejin; Guan, Xiaoqun; Koval, Olha M.; Chaudhary, Ashok K.; Cunha, Shane R.; Mohler, Peter J.; Martins, James B.; Song, Long-Sheng; Anderson, Mark E.

    2010-01-01

    Increasing evidence suggests that cardiac pacemaking is the result of two sinoatrial node (SAN) cell mechanisms: a voltage clock and a Ca2+ dependent process, or Ca2+ clock. The voltage clock initiates action potentials (APs) by SAN cell membrane potential depolarization from inward currents, of which the pacemaker current (If) is thought to be particularly important. A Ca2+ dependent process triggers APs when sarcoplasmic reticulum (SR) Ca2+ release activates inward current carried by the forward mode of the electrogenic Na+/Ca2+ exchanger (NCX). However, these mechanisms have mostly been defined in rodents or rabbits, but are unexplored in single SAN cells from larger animals. Here, we used patch-clamp and confocal microscope techniques to explore the roles of the voltage and Ca2+ clock mechanisms in canine SAN pacemaker cells. We found that ZD7288, a selective If antagonist, significantly reduced basal automaticity and induced irregular, arrhythmia-like activity in canine SAN cells. In addition, ZD7288 impaired but did not eliminate the SAN cell rate acceleration by isoproterenol. In contrast, ryanodine significantly reduced the SAN cell acceleration by isoproterenol, while ryanodine reduction of basal automaticity was modest (?14%) and did not reach statistical significance. Importantly, pretreatment with ryanodine eliminated SR Ca2+ release, but did not affect basal or isoproterenol-enhanced If. Taken together, these results indicate that voltage and Ca2+ dependent automaticity mechanisms coexist in canine SAN cells, and suggest If and SR Ca2+ release cooperate to determine baseline and catecholamine-dependent automaticity in isolated dog SAN cells. PMID:20380837

  17. Preliminary experience with the use of a programmable pacemaker.

    PubMed

    Morse, D; Fernandez, J; Samuel, A; Lemole, G; Parsonnet, V

    1975-05-01

    One hundred sixty-four patients, in whom new externally programmable pacemakers had been inserted, were studied over a two year period, beginning July, 1972. Following implantation, the rate and current output of this pacemaker could be changed at any time by a non-invasive technique involving electromagnetic pulse trains emitted by an external "programmer". In 89 percent of the patients it was possible to reduce battery output by half, implying greater longevity of the pacer in these cases. In 15 percent of the patients, manipulative control of the pacemaker rate was employed and found beneficial. PMID:1126191

  18. Of pacemakers and statistics: the actuarial method extended.

    PubMed

    Dussel, J; Wolbarst, A B; Scott-Millar, R N; Obel, I W

    1980-01-01

    Pacemakers cease functioning because of either natural battery exhaustion (nbe) or component failure (cf). A study of four series of pacemakers shows that a simple extension of the actuarial method, so as to incorporate Normal statistics, makes possible a quantitative differentiation between the two modes of failure. This involves the separation of the overall failure probability density function PDF(t) into constituent parts pdfnbe(t) and pdfcf(t). The approach should allow a meaningful comparison of the characteristics of different pacemaker types. PMID:6160497

  19. Thallium cardiac stressing by esophageal pacing

    SciTech Connect

    Allen, M.L.; Vacek, J.L.; Preston, D.F.; Robinson, R.G.; Feldkamp, M.J. )

    1989-09-01

    Forty-three patients were examined with the transesophageal pacing method of cardiac stressing and thallium imaging. Transesophageal cardiac pacing, using a pill electrode or a permanent pacemaker lead, is a safe alternative for patients who are physically unable to exercise. Prior studies suggest that transvenous right atrial pacing with thallium injection is equivalent to physical exercise thallium studies in the detection of coronary artery disease. The esophageal pacing bipolar electrode similarly increases heart rate without the necessity of transvenous pacing or fluoroscopy and without the adverse side effects often seen when using pharmacologic stressing agents (i.e., dipyridamole). The results compare well with cardiac catheterization, echocardiographic, and electrocardiographic results. Cardiac paced stress testing requires no sedation, is performed on an out-patient basis, and causes little if any discomfort for the patient.

  20. Influence of electromagnetic interference on implanted cardiac arrhythmia devices in and around a magnetically levitated linear motor car.

    PubMed

    Fukuta, Motoyuki; Mizutani, Noboru; Waseda, Katsuhisa

    2005-01-01

    This study was designed to determine the susceptibility of implanted cardiac arrhythmia devices to electromagnetic interference in and around a magnetically levitated linear motor car [High-Speed Surface Transport (HSST)]. During the study, cardiac devices were connected to a phantom model that had similar characteristics to the human body. Three pacemakers from three manufacturers and one implantable cardioverter-defibrillator (ICD) were evaluated in and around the magnetically levitated vehicle. The system is based on a normal conductive system levitated by the attractive force of magnets and propelled by a linear induction motor without wheels. The magnetic field strength at 40 cm from the vehicle in the nonlevitating state was 0.12 mT and that during levitation was 0.20 mT. The magnetic and electric field strengths on a seat close to the variable voltage/variable frequency inverter while the vehicle was moving and at rest were 0.13 mT, 2.95 V/m and 0.04 mT, 0.36 V/m, respectively. Data recorded on a seat close to the reactor while the vehicle was moving and at rest were 0.09 mT, 2.45 V/m and 0.05 mT, 1.46 V/m, respectively. Measured magnetic and electric field strengths both inside and outside the linear motor car were too low to result in device inactivation. No sensing, pacing, or arrhythmic interactions were noted with any pacemaker or ICD programmed in either bipolar and unipolar configurations. In conclusion, our data suggest that a permanent programming change or a device failure is unlikely to occur and that the linear motor car system is probably safe for patients with one of the four implanted cardiac arrhythmia devices used in this study under the conditions tested. PMID:16235032

  1. Which patient is most likely to benefit from a rate responsive pacemaker?

    PubMed

    Heinz, M; Wrl, H H; Alt, E; Theres, H; Blmer, H

    1988-11-01

    In order to provide information about indications for rate responsive pacing, we examined the exercise capacity of a typical collective of pacemaker patients. One hundred seven patients participated in the study, 50/107 (46.8%) suffered from sick sinus syndrome, 37/107 (34.6%) showed complete AV block, 12/107 (11.2%) had bradyarrhythmia and 8/107 (7.4%) had other diseases. All patients underwent treadmill exercise with increasing workloads up to the individual's maximum workload. We monitored heart rate, respiratory rate, workload, the subjective perception of stress according to the Borg scale, and the reason for the termination of exercise. Calculation of oxygen uptake was done according to an equation given by Givoni. During the tests, all implanted pacemakers have been programmed to VVI 70 mode. We found that all pacemaker patients showed a reduction of their exercise capacity compared to the age-related normal values. Particularly in patients with AV block or bradyarrhythmia, the maximum achievable workload often did not even reach levels of everyday activities such as going upstairs; patients with sick sinus syndrome showed slightly better exercise capability, probably due to the higher increase of average heart rate. Despite objective differences of maximum workload, all patients had the same subjective perception at the end of the tests; the course of respiratory rate indicated that all persons finished the tests in the range of individual maximum exercise capacity.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2463555

  2. Incidence of new onset atrial fibrillation in patients with permanent pacemakers and the relation to the pacing mode

    PubMed Central

    Said, Sarmad; Alkhateeb, Haider; Cooper, Chad J.; Gosavi, Sucheta; Dwivedi, Alok; Paez, David; Abedin, Zainul

    2014-01-01

    Background Atrial fibrillation is a relatively common arrhythmia often seen in patients with permanent pacemakers. In this study we aimed to assess the incidence of atrial fibrillation in patients whose pacemakers were programmed to pace in the right ventricle (VVI) and compared it with patients whose pacemakers were programmed in non-VVI mode(i.e. AAI or DDD). Material/Methods Records of the patients with permanent pacemaker or implantable-cardioverter-defibrillator were evaluated and analyzed. These patients had regular periodic follow-up evaluation over the last 10 years. (January 1, 2002 to December 31, 2012). Patient demographic, pacemaker data, pacing mode, review and analysis of arrhythmia log for occurrence of new atrial fibrillation and echocardiographic findings for left atrial size, mitral regurgitation, were analyzed and recorded. Left atrial size was classified as mild, moderate or severe enlargement, depending on the left atrial dimension. Results Average age was 68 years. There was no gender predominance (51% male). Mean follow-up duration was 6 years and 3 months. Hispanic population represented the majority of the patients (65.4%). Majority of the devices (80.0%) were programmed as DDD pacing mode. Fifty-five patients (52.8%) did not develop atrial fibrillation. 85.7% of the patients paced in VVI-mode had atrial fibrillation while atrial fibrillation occurred in 37.4% among patients paced in non-VVI-mode. This difference was statistically significant (P<0.0001). Conclusions Right ventricular pacing in a VVI mode was associated with higher incidence of atrial fibrillation, mitral regurgitation and left atrial enlargement. Non-VVI based pacing demonstrated lower incidence of new onset atrial fibrillation. PMID:24535068

  3. Intracardiac Origin of Heart Rate Variability, Pacemaker Funny Current and their Possible Association with Critical Illness

    PubMed Central

    Papaioannou, Vasilios E; Verkerk, Arie O; Amin, Ahmed S; de Bakker, Jaques MT

    2013-01-01

    Heart rate variability (HRV) is an indirect estimator of autonomic modulation of heart rate and is considered a risk marker in critical illness, particularly in heart failure and severe sepsis. A reduced HRV has been found in critically ill patients and has been associated with neuro-autonomic uncoupling or decreased baroreflex sensitivity. However, results from human and animal experimental studies indicate that intracardiac mechanisms might also be responsible for interbeat fluctuations. These studies have demonstrated that different membrane channel proteins and especially the so-called ‘funny’ current (If), an hyperpolarization-activated, inward current that drives diastolic depolarization resulting in spontaneous activity in cardiac pacemaker cells, are altered during critical illness. Furthermore, membrane channels kinetics seem to have significant impact upon HRV, whose early decrease might reflect a cellular metabolic stress. In this review article we present research findings regarding intracardiac origin of HRV, at the cellular level and in both isolated sinoatrial node and whole ex vivo heart preparations. In addition, we will review results from various experimental studies that support the interrelation between If and HRV during endotoxemia. We suggest that reduced HRV during sepsis could also be associated with altered pacemaker cell membrane properties, due to ionic current remodeling. PMID:22920474

  4. Dynamic tricuspid valve stenosis induced with a pacemaker lead: a case report.

    PubMed

    Skoric, Bosko; Baricevic, Zeljko; Brida, Margarita; Samardzic, Jure; Jurin, Hrvoje; Milicic, Davor

    2014-01-01

    Isolated severe tricuspid valve stenosis due to an endocardial pacemaker lead is extremely rare, and is usually caused by either fibrosis of a perforated or lacerated leaflet, or fibrotic adherence between the lead and the valvular apparatus. Reported cases typically include clinical manifestations of both systemic venous stasis and low cardiac output. The case is presented of a 20-year-old female with a surgically repaired congenital heart disease who developed severe tricuspid stenosis at six years after the implantation of a DDD pacemaker. Unexpectedly, the patient had no signs of venous stasis and suffered only from exercise intolerance. Right heart catheterization under fluoroscopic guidance revealed an atrial lead forming a loop at the level of the tricuspid valve. A paradoxical inspiratory decrease in the transvalvular diastolic gradient, caused by the caudal heart motion and straightening of the loop during inspiration, was noted. Such a dynamic nature with a temporary inspiratory relief of the obstruction may explain the partial clinical presentation of tricuspid stenosis in this case. The lead was removed and the tricuspid valve repaired surgically, after which the patient's recovery was uneventful with normalization of exercise tolerance. PMID:24779342

  5. Pacemakers in a Reaction-Diffusion Mechanics System

    NASA Astrophysics Data System (ADS)

    Keldermann, R. H.; Nash, M. P.; Panfilov, A. V.

    2007-07-01

    Non-linear waves of excitation are found in various biological, physical and chemical systems and are often accompanied by deformations of the medium. In this paper, we numerically study wave propagation in a deforming excitable medium using a two-variable reaction-diffusion system coupled with equations of continuum mechanics. We study the appearance and dynamics of different excitation patterns organized by pacemakers that occur in the medium as a result of deformation. We also study the interaction of several pacemakers with each other and the characteristics of pacemakers in the presence of heterogeneities in the medium. We found that mechanical deformation not only induces pacemakers, but also has a pronounced effect on spatial organization of various excitation patterns. We show how these effects are modulated by the size of the medium, the location of the initial stimulus, and the properties of the reaction-diffusion-mechanics feedback.

  6. Severe pain attack associated with neurocardiogenic syncope induced by glossopharyngeal neuralgia: successful treatment with carbamazepine and a permanent pacemaker -a case report-.

    PubMed

    Kim, Seung Ho; Han, Kyung Ream; Kim, Do Wan; Lee, Jae Woo; Park, Ki Bum; Lee, Ji Young; Kim, Chan

    2010-09-01

    Glossopharyneal neuralgia (GPN) is generally considered to be a pain disease. However, it can be also be a life-threatening cardiac cause of syncope. Neuralgia in the throat and neck can trigger severe bradycardia up to the point of asystole, which can progress to cardiac syncope with or without seizures. A 65 year-old male patient diagnosed with glossopharyngeal neuralgia complained of severe paroxysmal pain in his right chin and ear followed by bradycardia, aystole and syncope. We report a case successfully treated with a permanent pacemaker and carbamazepine in a patient with GPN who had syncopal attacks preceded by paroxysms of pain. PMID:20830270

  7. Integration of a Notch-dependent mesenchymal gene program and Bmp2-driven cell invasiveness regulates murine cardiac valve formation

    PubMed Central

    Luna-Zurita, Luis; Prados, Beln; Grego-Bessa, Joaquim; Luxn, Guillermo; del Monte, Gonzalo; Bengura, Alberto; Adams, Ralf H.; Prez-Pomares, Jos Mara; de la Pompa, Jos Luis

    2010-01-01

    Cardiac valve formation is crucial for embryonic and adult heart function. Valve malformations constitute the most common congenital cardiac defect, but little is known about the molecular mechanisms regulating valve formation and homeostasis. Here, we show that endocardial Notch1 and myocardial Bmp2 signal integration establish a valve-forming field between 2 chamber developmental domains. Patterning occurs through the activation of endocardial epithelial-to-mesenchymal transition (EMT) exclusively in prospective valve territories. Mice with constitutive endocardial Notch1 activity ectopically express Hey1 and Heyl. They also display an activated mesenchymal gene program in ventricles and a partial (noninvasive) EMT in vitro that becomes invasive upon BMP2 treatment. Snail1, TGF-?2, or Notch1 inhibition reduces BMP2-induced ventricular transformation and invasion, whereas BMP2 treatment inhibits endothelial Gsk3?, stabilizing Snail1 and promoting invasiveness. Integration of Notch and Bmp2 signals is consistent with Notch1 signaling being attenuated after myocardial Bmp2 deletion. Notch1 activation in myocardium extends Hey1 expression to nonchamber myocardium, represses Bmp2, and impairs EMT. In contrast, Notch deletion abrogates endocardial Hey gene transcription and extends Bmp2 expression to the ventricular endocardium. This embryonic Notch1-Bmp2-Snail1 relationship may be relevant in adult valve disease, in which decreased NOTCH signaling causes valve mesenchyme cell formation, fibrosis, and calcification. PMID:20890042

  8. Automatic Segmentation of the Left Ventricle in Cardiac MRI Using Local Binary Fitting Model and Dynamic Programming Techniques

    PubMed Central

    Hu, Huaifei; Gao, Zhiyong; Liu, Liman; Liu, Haihua; Gao, Junfeng; Xu, Shengzhou; Li, Wei; Huang, Lu

    2014-01-01

    Segmentation of the left ventricle is very important to quantitatively analyze global and regional cardiac function from magnetic resonance. The aim of this study is to develop a novel algorithm for segmenting left ventricle on short-axis cardiac magnetic resonance images (MRI) to improve the performance of computer-aided diagnosis (CAD) systems. In this research, an automatic segmentation method for left ventricle is proposed on the basis of local binary fitting (LBF) model and dynamic programming techniques. The validation experiments are performed on a pool of data sets of 45 cases. For both endo- and epi-cardial contours of our results, percentage of good contours is about 93.5%, the average perpendicular distance are about 2 mm. The overlapping dice metric is about 0.91. The regression and determination coefficient between the experts and our proposed method on the LV mass is 1.038 and 0.9033, respectively; they are 1.076 and 0.9386 for ejection fraction (EF). The proposed segmentation method shows the better performance and has great potential in improving the accuracy of computer-aided diagnosis systems in cardiovascular diseases. PMID:25500580

  9. Venous obstruction in permanent pacemaker patients: an isotopic study

    SciTech Connect

    Pauletti, M.; Di Ricco, G.; Solfanelli, S.; Marini, C.; Contini, C.; Giuntini, C.

    1981-01-01

    Isotope venography was used to study the venous circulation proximal to the superior vena cava in two groups of pacemaker patients, one with a single endocavitary electrode and the other with multiple pacing catheters. A control group of patients without pacemakers was also studied. Numerous abnormalities were found, especially in the group with multiple electrodes. These findings suggest that venous obstruction is a common complication of endocardial pacing.

  10. Fistula Formation 6 Years after Removal of Infected Pacemaker Leads

    PubMed Central

    Schroeter, Thomas; Kiefer, Philipp; Sauer, Matthias; Mohr, Friedrich Wilhelm

    2015-01-01

    We describe a case of a male patient who presented with a chronic ulcer below the left clavicle. Six years before the present admission a permanent pacemaker, including leads, was explanted related to endocarditis. The initial working hypothesis suspected an infected sebaceous gland as the cause of ulceration. After two periods of unsuccessful surgical treatment of the gland, further examination identified a small pacemaker lead fragment underneath the articulation between sternum and clavicle as a possible reason. PMID:26693129

  11. Which Factors Unexpectedly Increase Depressive Symptom Severity in Patients at the End of a Cardiac Rehabilitation Program?

    PubMed Central

    Komasi, Saeid; Montazeri, Nafiseh; Masoumi, Masoumali; Soroush, Ali; Ezzati, Parvin

    2015-01-01

    Objective To investigate predictors of depressive symptom aggravation at the end of a cardiac rehabilitation (CR) program. Methods The design of the study was retrospective. The administrative data were obtained from the database of the CR department of a heart hospital in Iran. The demographic and clinical information of 615 CR patients between January 2000 and January 2010 was analyzed using binary logistic regression analysis. Results The results showed that 10.7% of the patients completed the CR program with aggravated depressive symptoms. After adjustment for gender, age, and pre-intervention depression score, lower education level (p<0.05) and smoking (p<0.01) were significant predictors of increased depressive symptoms at the end of the program. Our model variables could explain 6% to 13% of the dependent variable variance. Conclusion The results suggest that targeting patients who are less literate or who smoke could allow for taking the required measures to prevent or control depression at the end of a CR program. It is suggested that future studies consider other variables. PMID:26798600

  12. Predictors of severe tricuspid regurgitation in patients with permanent pacemaker or automatic implantable cardioverter-defibrillator leads.

    PubMed

    Najib, Mohammad Q; Vittala, Satya S; Challa, Suresh; Raizada, Amol; Tondato, Fernando J; Lee, Howard R; Chaliki, Hari P

    2013-01-01

    Patients with permanent pacemaker or automatic implantable cardioverter-defibrillator (AICD) leads have an increased prevalence of tricuspid regurgitation. However, the roles of cardiac rhythm and lead-placement duration in the development of severe tricuspid regurgitation are unclear. We reviewed echocardiographic data on 26 consecutive patients who had severe tricuspid regurgitation after permanent pacemaker or AICD placement; before treatment, they had no organic tricuspid valve disease, pulmonary hypertension, left ventricular dysfunction, or severe tricuspid regurgitation. We compared the results to those of 26 control subjects who had these same devices but no more than mild tricuspid regurgitation. The patients and control subjects were similar in age (mean, 81 6 vs 81 8 yr; P = 0.83), sex (male, 42% vs 46%; P = 0.78), and left ventricular ejection fraction (0.60 0.06 vs 0.58 0.05; P = 0.4). The patients had a higher prevalence of atrial fibrillation (92% vs 65%; P=0.01) and longer median duration of pacemaker or AICD lead placement (49.5 vs 5 mo; P < 0.001). After adjusting for age, sex, and right ventricular systolic pressure by multivariate logistic regression analysis, we found that atrial fibrillation (odds ratio=6.4; P = 0.03) and duration of lead placement (odds ratio=1.5/yr; P = 0.001) were independently associated with severe tricuspid regurgitation. Out study shows that atrial fibrillation and longer durations of lead placement might increase the risk of severe tricuspid regurgitation in patients with permanent pacemakers or AICDs. PMID:24391312

  13. [{sup 13}N] Ammonia Cardiac Program At West Virginia University Health Sciences

    SciTech Connect

    Armbruster, John M.

    2011-06-01

    Due to the shortage of the more traditional cardiac imagining isotopes, specifically, Technicium-99, the Cardiologists at WVU have had to look to alternative imagining techniques such as PET. This has led to a dramatic increase in the use of [{sup 13}N] Ammonia PET scans at the Health Sciences Center. The patient load has gone from one to two patients one day a week to typically two to three patients, two days a week, with occasional add-on in-house patients; each patient typically requiring two target irradiations. In this paper, we will discuss the process that is being used to meet this increased demand from the production of the isotope through the final result.

  14. [13N] Ammonia Cardiac Program At West Virginia University Health Sciences

    NASA Astrophysics Data System (ADS)

    Armbruster, John M.

    2011-06-01

    Due to the shortage of the more traditional cardiac imagining isotopes, specifically, Technicium-99, the Cardiologists at WVU have had to look to alternative imagining techniques such as PET. This has led to a dramatic increase in the use of [13N] Ammonia PET scans at the Health Sciences Center. The patient load has gone from one to two patients one day a week to typically two to three patients, two days a week, with occasional add-on in-house patients; each patient typically requiring two target irradiations. In this paper, we will discuss the process that is being used to meet this increased demand from the production of the isotope through the final result.

  15. Industrial Fitness, Adult Fitness, and Cardiac Rehabilitation. Graduate Programs Specific to Training Exercise Specialists.

    ERIC Educational Resources Information Center

    Wilson, Philip K.; Hall, Linda K.

    1984-01-01

    With the increase in industrial and adult fitness and rehabilitation programs, more individuals qualified as exercise program professionals are needed. This article discusses universities and colleges that offer specialized graduate programs. Entrance criteria, prerequisites and deficiencies, degree requirements, and field experience training for

  16. Simulation of Ectopic Pacemakers in the Heart: Multiple Ectopic Beats Generated by Reentry inside Fibrotic Regions

    PubMed Central

    Gouvêa de Barros, Bruno; Weber dos Santos, Rodrigo; Lobosco, Marcelo; Alonso, Sergio

    2015-01-01

    The inclusion of nonconducting media, mimicking cardiac fibrosis, in two models of cardiac tissue produces the formation of ectopic beats. The fraction of nonconducting media in comparison with the fraction of healthy myocytes and the topological distribution of cells determines the probability of ectopic beat generation. First, a detailed subcellular microscopic model that accounts for the microstructure of the cardiac tissue is constructed and employed for the numerical simulation of action potential propagation. Next, an equivalent discrete model is implemented, which permits a faster integration of the equations. This discrete model is a simplified version of the microscopic model that maintains the distribution of connections between cells. Both models produce similar results when describing action potential propagation in homogeneous tissue; however, they slightly differ in the generation of ectopic beats in heterogeneous tissue. Nevertheless, both models present the generation of reentry inside fibrotic tissues. This kind of reentry restricted to microfibrosis regions can result in the formation of ectopic pacemakers, that is, regions that will generate a series of ectopic stimulus at a fast pacing rate. In turn, such activity has been related to trigger fibrillation in the atria and in the ventricles in clinical and animal studies. PMID:26583127

  17. Low dimensional chaos in cardiac tissue

    NASA Astrophysics Data System (ADS)

    Chialvo, Dante R.; Gilmour, Robert F., Jr.; Jalife, Jose

    1990-02-01

    CHAOS is a term uvd to characterize aperiodic activity arising in a dynamical system, or in a set of equations describing the system's temporal evolution as a result of a deterministic mechanism that has sensitive dependence on initial conditions1. Chaos, in that sense, has been proposed to make an important contribution to normal and abnormal cardiac rhythms2-6. To date, however, descriptions of chaos in heart tissue have been limited primarily to periodically forced cardiac pacemakers2,6. Because many cardiac rhythm disturbances, particularly those initiated or perpetuated by re-entrant excitation, originate from within non-pacemaker cardiac tissues7-9, demonstrations of chaos in non-pacemaker tissue might provide a deterministic explanation for a wide variety of complex dysrhythmias. Here we report experimental evidence for chaotic patterns of activation and action potential characteristics in externally driven, non-spontaneously active Purkinje fibres and ventricular muscle. The results indicate that there is an apparent link between the mechanism of low dimensional chaos and the occurrence of reflected responses which could lead to more spatially disorganized phenomena. A detailed mechanism for the low dimensional chaos observed experimentally is pursued using a difference equation model. Critical features of the model include a non-monotonic relationship between recovery time during rhythmic stimulation and the state of membrane properties, and a steeply sloped recovery of membrane properties over certain ranges of recovery times. Besides explaining our results, the analytical model may pertain to irregular dynamics in other excitable systems, particularly the intact dysrhythmic heart.

  18. Radiation induced failures of complementary metal oxide semiconductor containing pacemakers: a potentially lethal complication

    SciTech Connect

    Lewin, A.A.; Serago, C.F.; Schwade, J.G.; Abitbol, A.A.; Margolis, S.C.

    1984-10-01

    New multi-programmable pacemakers frequently employ complementary metal oxide semiconductors (CMOS). This circuitry appears more sensitive to the effects of ionizing radiation when compared to the semiconductor circuits used in older pacemakers. A case of radiation induced runaway pacemaker in a CMOS device is described. Because of this and other recent reports of radiation therapy-induced CMOS type pacemaker failure, these pacemakers should not be irradiated. If necessary, the pacemaker can be shielded or moved to a site which can be shielded before institution of radiation therapy. This is done to prevent damage to the CMOS circuit and the life threatening arrythmias which may result from such damage.

  19. A 9-year-old boy with severe diphtherial infection and cardiac complications.

    PubMed

    Washington, Charles Henry; Issaranggoon na ayuthaya, Satja; Makonkawkeyoon, Krit; Oberdorfer, Peninnah

    2014-01-01

    The incidence of diphtheria has decreased since the introduction of an effective vaccine. However, in countries with low vaccination rates it has now become a re-emerging disease. Complications from diphtheria commonly include upper airway obstruction and cardiac complications. We present a 9-year-old boy who was diagnosed with diphtheria. He presented with fever, tonsilar plaques, respiratory failure and an incomplete vaccination history. He was endotracheal intubated and received diphtheria antitoxin and penicillin on the first day of hospitalisation. He developed progressive arrhythmias and fulminant myocarditis despite early identification and treatment with equine antitoxin and antibiotics. After a temporary transvenous pacemaker insertion due to third-degree atrioventricular block and hypotension for 1 week, he developed myocardial perforation from the pacemaker tip resulting in pericardial effusion. The treatment included emergency pericardiocentesis and pacemaker removal. His electrocardiogram showed a junctional rhythm with occasional premature ventricular complexes. He then developed ventricular tachycardia and cardiac arrest and finally died. PMID:25414216

  20. Cardiac pacing and aviation.

    PubMed

    Toff, W D; Edhag, O K; Camm, A J

    1992-12-01

    Certain applicants with stable disturbances of rhythm or conduction requiring cardiac pacing, in whom no other disqualifying condition is present, may be considered fit for medical certification restricted to multi-crew operations. The reliability of modern pacing systems appears adequate to permit restricted certification even in pacemaker dependent subjects except for certain models of pacemakers and leads known to be at increased risk of failure. These are to be avoided. There is little evidence to suggest that newer devices are any more reliable than their predecessors. Single and dual chamber systems appear to have similar reliability up to 4 years, after which time significant attrition of dual chamber devices occurs, principally due to battery depletion. All devices require increased scrutiny as they approach their end of life as predicted from longevity data and pacing characteristics. Unipolar and bipolar leads are of similar reliability, apart from a number of specific bipolar polyurethane leads which have been identified. Atrial leads, particularly those without active fixation, are less secure than ventricular leads and applicants who are dependent on atrial sensing or pacing should be denied certification. Bipolar leads are to be preferred due to the lower risk of myopotential and exogenous EMI. Sensor-driven adaptive-rate pacing systems using active sensors may have reduced longevity and require close scrutiny. Activity-sensing devices using piezoelectric crystal sensors may be subject to significant rate rises in rotary wing aircraft. The impracticality of restricted certification in helicopters will, in any event, preclude certification. Such devices would best be avoided in hovercraft (air cushioned vehicle) pilots. Only minor rate rises are likely in fixed-wing aircraft which are unlikely to be of significance. Anti-tachycardia devices and implanted defibrillators are inconsistent with any form of certification to fly. PMID:1493823

  1. Dual-chamber pacemakers for treating symptomatic bradycardia due to sick sinus syndrome without atrioventricular block: a systematic review and economic evaluation.

    PubMed Central

    Edwards, Steven J; Karner, Charlotta; Trevor, Nicola; Wakefield, Victoria; Salih, Fatima

    2015-01-01

    BACKGROUND Bradycardia [resting heart rate below 60 beats per minute (b.p.m.)] can be caused by conditions affecting the natural pacemakers of the heart, such as sick sinus syndrome (SSS) and atrioventricular (AV) blocks. People suffering from bradycardia may present with palpitations, exercise intolerance and fainting. The only effective treatment for patients suffering from symptomatic bradycardia is implantation of a permanent pacemaker. OBJECTIVE To appraise the clinical effectiveness and cost-effectiveness of dual-chamber pacemakers compared with single-chamber atrial pacemakers for treating symptomatic bradycardia in people with SSS and no evidence of AV block. DATA SOURCES All databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Health Technology Assessment database, NHS Economic Evaluations Database) were searched from inception to June 2014. METHODS A systematic review of the clinical and economic literature was carried out in accordance with the general principles published by the Centre for Reviews and Dissemination. Randomised controlled trials (RCTs) evaluating dual-chamber and single-chamber atrial pacemakers and economic evaluations were included. Pairwise meta-analysis was carried out. A de novo economic model was developed. RESULTS Of 493 references, six RCTs were included in the review. The results were predominantly influenced by the largest trial DANPACE. Dual-chamber pacing was associated with a statistically significant reduction in reoperation [odds ratio (OR) 0.48, 95% confidence interval (CI) 0.36 to 0.63] compared with single-chamber atrial pacing. The difference is primarily because of the development of AV block requiring upgrade to a dual-chamber device. The risk of paroxysmal atrial fibrillation was also reduced with dual-chamber pacing compared with single-chamber atrial pacing (OR 0.75, 95% CI 0.59 to 0.96). No statistically significant difference was found between the pacing modes for mortality, heart failure, stroke, chronic atrial fibrillation or quality of life. However, the risk of developing heart failure may vary with age and device. The de novo economic model shows that dual-chamber pacemakers are more expensive and more effective than single-chamber atrial devices, resulting in a base-case incremental cost-effectiveness ratio (ICER) of £6506. The ICER remains below £20,000 in probabilistic sensitivity analysis, structural sensitivity analysis and most scenario analyses and one-way sensitivity analyses. The risk of heart failure may have an impact on the decision to use dual-chamber or single-chamber atrial pacemakers. Results from an analysis based on age (> 75 years or ≤ 75 years) and risk of heart failure indicate that dual-chamber pacemakers dominate single-chamber atrial pacemakers (i.e. are less expensive and more effective) in older patients, whereas dual-chamber pacemakers are dominated by (i.e. more expensive and less effective) single-chamber atrial pacemakers in younger patients. However, these results are based on a subgroup analysis and should be treated with caution. CONCLUSIONS In patients with SSS without evidence of impaired AV conduction, dual-chamber pacemakers appear to be cost-effective compared with single-chamber atrial pacemakers. The risk of developing a complete AV block and the lack of tools to identify patients at high risk of developing the condition argue for the implantation of a dual-chamber pacemaker programmed to minimise unnecessary ventricular pacing. However, considerations have to be made around the risk of developing heart failure, which may depend on age and device. STUDY REGISTRATION This study is registered as PROSPERO CRD42013006708. FUNDING The National Institute for Health Research Health Technology Assessment programme. PMID:26293406

  2. Medium-Term Effectiveness of a Comprehensive Internet-Based and Patient-Specific Telerehabilitation Program With Text Messaging Support for Cardiac Patients: Randomized Controlled Trial

    PubMed Central

    Hansen, Dominique; Coninx, Karin; Vandervoort, Pieter; Vandijck, Dominique; Hens, Niel; Van Craenenbroeck, Emeline; Van Driessche, Niels; Dendale, Paul

    2015-01-01

    Background Cardiac telerehabilitation has been introduced as an adjunct or alternative to conventional center-based cardiac rehabilitation to increase its long-term effectiveness. However, before large-scale implementation and reimbursement in current health care systems is possible, well-designed studies on the effectiveness of this new additional treatment strategy are needed. Objective The aim of this trial was to assess the medium-term effectiveness of an Internet-based, comprehensive, and patient-tailored telerehabilitation program with short message service (SMS) texting support for cardiac patients. Methods This multicenter randomized controlled trial consisted of 140 cardiac rehabilitation patients randomized (1:1) to a 24-week telerehabilitation program in combination with conventional cardiac rehabilitation (intervention group; n=70) or to conventional cardiac rehabilitation alone (control group; n=70). In the telerehabilitation program, initiated 6 weeks after the start of ambulatory rehabilitation, patients were stimulated to increase physical activity levels. Based on registered activity data, they received semiautomatic telecoaching via email and SMS text message encouraging them to gradually achieve predefined exercise training goals. Patient-specific dietary and/or smoking cessation advice was also provided as part of the telecoaching. The primary endpoint was peak aerobic capacity (VO2 peak). Secondary endpoints included accelerometer-recorded daily step counts, self-assessed physical activities by International Physical Activity Questionnaire (IPAQ), and health-related quality of life (HRQL) assessed by the HeartQol questionnaire at baseline and at 6 and 24 weeks. Results Mean VO2 peak increased significantly in intervention group patients (n=69) from baseline (mean 22.46, SD 0.78 mL/[min*kg]) to 24 weeks (mean 24.46, SD 1.00 mL/[min*kg], P<.01) versus control group patients (n=70), who did not change significantly (baseline: mean 22.72, SD 0.74 mL/[min*kg]; 24 weeks: mean 22.15, SD 0.77 mL/[min*kg], P=.09). Between-group analysis of aerobic capacity confirmed a significant difference between the intervention group and control group in favor of the intervention group (P<.001). At 24 weeks, self-reported physical activity improved more in the intervention group compared to the control group (P=.01) as did the global HRQL score (P=.01). Conclusions This study showed that an additional 6-month patient-specific, comprehensive telerehabilitation program can lead to a bigger improvement in both physical fitness (VO2 peak) and associated HRQL compared to center-based cardiac rehabilitation alone. These results are supportive in view of possible future implementation in standard cardiac care. PMID:26206311

  3. Technology utilization program report

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The application of aerospace technology to the solution of public health and industrial problems is reported. Data cover: (1) development of an externally rechargeable cardiac pacemaker, (2) utilization of ferrofluids-colloidal suspensions of ferrite particles - in the efficient separation of nonferrous metals as Ni, Zn, Cu, and Al from shredded automobile scrap, and (3) development of a breathing system for fire fighters.

  4. Illness cognition as a predictor of exercise habits and participation in cardiac prevention and rehabilitation programs after acute coronary syndrome

    PubMed Central

    2013-01-01

    Background Despite well-established medical recommendations, many cardiac patients do not exercise regularly either independently or through formal cardiac prevention and rehabilitation programs (CPRP). This non-adherence is even more pronounced among minority ethnic groups. Illness cognition (IC), i.e. the way people perceive the situation they encounter, has been recognized as a crucial determinant of health-promoting behavior. Few studies have applied a cognitive perspective to explain the disparity in exercising and CPRP attendance between cardiac patients from different ethnic backgrounds. Based on the Health Belief Model (HBM) and the Common Sense Model (CSM), the objective was to assess the association of IC with exercising and with participation in CPRP among Jewish/majority and Arab/minority patients hospitalized with acute coronary syndrome. Methods Patients (N = 420) were interviewed during hospitalization (January-2009 until August- 2010) about IC, with 6-month follow-up interviews about exercise habits and participation in CPRP. Determinants that predict active lifestyle and participation in CPRP were assessed using backward stepwise logistic regression. Results Perceived susceptibility to heart disease and sense and personal control were independently associated with exercising 6 months after the acute event (OR = 0.58, 95% CI: 0.42-0.80 and OR = 1.09, 95% CI: 1.02-1.17, per unit on a 5-point scale). Perceived benefits of regular exercise and a sense of personal control were independently associated with participation in CPRP (OR = 1.56, 95% CI: 1.12-2.16 and OR = 1.08, 95% CI: 1.01-1.15, per unit on a 5-point scale). None of the IC variables assessed could explain the large differences in health promoting behaviors between the majority and minority ethnic groups. Conclusions IC should be taken into account in future interventions to promote physical activity and participation in CPRP for both ethnic groups. Yet, because IC failed to explain the gap between Arab and Jewish patients in those behaviors, other explanatory pathways such as psychological state or cultural views should be considered as potential areas for further research. PMID:24119027

  5. Pacemaker endocarditis caused by Propionibacterium acnes in an adult patient with Ebstein's anomaly: a report of a rare case.

    PubMed

    Santo, Karla R E; Franceschi, Vinicius; Campos, Andr C B; Monteiro, Thassa S; Barbosa, Giovanna I F; Dantas, Angela; Lamas, Cristiane C

    2014-10-01

    We report a rare case of a Brazilian adult woman with Ebstein's Anomaly who presented with pacemaker endocarditis caused by Propionibacterium acnes. Ebstein's Anomaly is a rare congenital malformation of the heart. Infective endocarditis is defined as an infection of heart valves, of the mural endocardium, of a septal defect, or of a cardiac electronic implantable device. Propionibacterium acnes is a skin commensal bacterium, that is usually considered as a contaminant, but can, on rare occasions, cause serious infections including endocarditis of prosthetic valves, native valves and cardiac electronic implantable devices. Diagnosis was made after nearly two years of investigation by identification of the organism by the MALDI-TOF technique and transoesophageal echocardiogram. The patient was successfully treated with daptomycin and device removal. She remains free of endocarditis after 32 months of follow-up. PMID:25047281

  6. Radioisotope thermoelectric generators for implanted pacemakers

    SciTech Connect

    Pustovalov, A.A.; Bovin, A.V.; Fedorets, V.I.; Shapovalov, V.P.

    1986-08-01

    This paper discusses the development and application of long-life lithium batteries and the problems associated with miniature radioisotope thermoelectric generators (RITEG) with service lives of 10 years or longer. On eof the main problems encountered when devising a radioisotope heat source (RHS) for an RITEG is to obtain biomedical /sup 238/PuO/sub 2/ with a specific neutron yield of 3.10/sup 3/-4.10/sup 3/ (g /SUP ./ sec)/sup -1/, equivalent to metallic Pu 238, and with a content of gamma impurities sufficient to ensure a permissible exposure a permissible exposure does rate (EDR) of a mixture of neutron and gamma radiation. After carrying out the isotope exchange and purifying the initial sample of its gamma impurity elements, the authors obtain biomedical Pu 238 satisfying the indicated requirements king suitable for use in the power packs of medical devices. Taking the indicated specifications into account, the Ritm-1o and gamma radioisotope heat sources were designed, built, tested in models and under natural conditions, and then into production as radioisotope thermoelectric generators designed to power the electronic circuits of implanted pacemakers. The Ritm-MT and Gemma radioisotope thermoelectric generators described are basic units, which can be used as self-contained power supplies for electronic equipment with power requirements in the micromilliwatt range.

  7. Specialised pacemaking cells in the rabbit urethra.

    PubMed

    Sergeant, G P; Hollywood, M A; McCloskey, K D; Thornbury, K D; McHale, N G

    2000-07-15

    1. Collagenase dispersal of strips of rabbit urethra yielded, in addition to normal spindle-shaped smooth muscle cells, a small proportion of branched cells which resembled the interstitial cells of Cajal dispersed from canine colon. These were clearly distinguishable from smooth muscle in their appearance under the phase-contrast microscope, their immunohistochemistry and their ultrastructure. They had abundant vimentin filaments but no myosin, a discontinuous basal lamina, sparse rough endoplasmic reticulum, many mitochondria and a well-developed smooth endoplasmic reticulum. 2. Interstitial cells were non-contractile but exhibited regular spontaneous depolarisations in current clamp. These could be increased in frequency by noradrenaline and blocked by perfusion with calcium-free solution. In voltage clamp they showed abundant calcium-activated chloride current and spontaneous transient inward currents which could be blocked by chloride channel blockers. 3. The majority of smooth muscle cells were vigorously contractile when stimulated but did not show spontaneous electrical activity in current clamp. In voltage clamp, smooth muscle cells showed very little calcium-activated chloride current. 4. We conclude that there are specialised pacemaking cells in the rabbit urethra that may be responsible for initiating the slow waves recorded from smooth muscle cells in the intact syncitium. PMID:10896724

  8. Nonphotic entrainment of the human circadian pacemaker

    NASA Technical Reports Server (NTRS)

    Klerman, E. B.; Rimmer, D. W.; Dijk, D. J.; Kronauer, R. E.; Rizzo, J. F. 3rd; Czeisler, C. A.

    1998-01-01

    In organisms as diverse as single-celled algae and humans, light is the primary stimulus mediating entrainment of the circadian biological clock. Reports that some totally blind individuals appear entrained to the 24-h day have suggested that nonphotic stimuli may also be effective circadian synchronizers in humans, although the nonphotic stimuli are probably comparatively weak synchronizers, because the circadian rhythms of many totally blind individuals "free run" even when they maintain a 24-h activity-rest schedule. To investigate entrainment by nonphotic synchronizers, we studied the endogenous circadian melatonin and core body temperature rhythms of 15 totally blind subjects who lacked conscious light perception and exhibited no suppression of plasma melatonin in response to ocular bright-light exposure. Nine of these fifteen blind individuals were able to maintain synchronization to the 24-h day, albeit often at an atypical phase angle of entrainment. Nonphotic stimuli also synchronized the endogenous circadian rhythms of a totally blind individual to a non-24-h schedule while living in constant near darkness. We conclude that nonphotic stimuli can entrain the human circadian pacemaker in some individuals lacking ocular circadian photoreception.

  9. Different response of left ventricular dimensions to nitroglycerin in patients with artificial pacemaker. A possible significance of reflex tachycardia for the reduction of LV cavity after nitroglycerin.

    PubMed

    Kamei, K; Aizawa, Y; Yazawa, Y; Shibata, A; Takeuchi, Y

    1984-12-01

    The effects of nitroglycerin (NTG) on cardiac function can be evaluated by echocardiography. In this paper, we discuss the effects of NTG on cardiac function in two groups of subjects, one with artificial pacemakers implanted with a fixed heart rate, and the other examined as the control group. Left ventricular dimension was obtained in the standard manner using the electronic sector scanning system of Toshiba SSH-11A. Left ventricular end-diastolic and end-systolic dimensions (Dd and Ds) were obtained in each case and the ejection fraction was calculated. After the sublingual administration of NTG (0.6 mg), the blood pressure decreased in both groups. The ventricular rate was fixed in the pacemaker group but increased significantly in the control group. Dd and Ds were found to decrease only in the control group. The ejection fraction showed an increase in the majority of the control group but remained unchanged in the pacemaker group. Heart rate change therefore may play a role in dimensional change and pumping function of heart after NTG. PMID:6439908

  10. Measurement of functional capacity requirements of police officers to aid in development of an occupation-specific cardiac rehabilitation training program.

    PubMed

    Adams, Jenny; Schneider, Jonna; Hubbard, Matthew; McCullough-Shock, Tiffany; Cheng, Dunlei; Simms, Kay; Hartman, Julie; Hinton, Paul; Strauss, Danielle

    2010-01-01

    This study was designed to measure the functional capacity of healthy subjects during strenuous simulated police tasks, with the goal of developing occupation-specific training for cardiac rehabilitation of police officers. A calibrated metabolic instrument and an oxygen consumption data collection mask were used to measure the oxygen consumption and heart rates of 30 Dallas Police Academy officers and cadets as they completed an 8-event obstacle course that simulated chasing, subduing, and handcuffing a suspect. Standard target heart rates (85% of age-predicted maximum heart rate, or 0.85 x [220 - age]) and metabolic equivalents (METs) were calculated; a matched-sample t test based on differences between target and achieved heart rate and MET level was used for statistical analysis. Peak heart rates during the obstacle course simulation were significantly higher than the standard target heart rates (those at which treadmill stress tests in physicians' offices are typically stopped) (t(29) = 12.81, P < 0.001) and significantly higher than the suggested maximum of 150 beats/min during cardiac rehabilitation training (t(29) = 17.84, P < 0.001). Peak MET levels during the obstacle course simulation were also significantly higher than the goal level (8 METs) that patients typically achieve in a cardiac rehabilitation program (t(29) = 14.73, P < 0.001). We conclude that police work requires a functional capacity greater than that typically attained in traditional cardiac rehabilitation programs. Rehabilitation professionals should consider performing maximal stress tests and increasing the intensity of cardiac rehabilitation workouts to effectively train police officers who have had a cardiac event. PMID:20157495

  11. Spiral-pacemaker interactions in a mathematical model of excitable medium

    NASA Astrophysics Data System (ADS)

    Shajahan, T. K.; Borek, Bart?omiej; Shrier, Alvin; Glass, Leon

    2013-02-01

    Interactions of a spiral wave with a pacemaker is studied in a mathematical model of two dimensional excitable medium. Faster pacemakers emitting target waves can abolish spirals by driving them to the border of the medium. Our study shows that a slower pacemaker can modify spiral wave behavior by changing the motion of the spiral core. We analyze the dynamics of the spiral wave near the spiral core and away from the core as a function of size and period of the pacemaker. The pacemaker can cause the spiral wave to drift towards it, and either speed up or slow down the reentrant activity. Furthermore, the drift induced by the pacemaker can result in irregular or quasiperiodic dynamics even at sites away from the pacemaker. These results highlight the influence of pacemakers on complex spiral wave dynamics.

  12. Onboarding advanced practice nurses: development of an orientation program in a cardiac center.

    PubMed

    Goldschmidt, Karen; Rust, Donna; Torowicz, Deborah; Kolb, Susan

    2011-01-01

    The advanced practice nurse (APN) is critical to continuity of patient care, particularly in an innovative and research-intensive environment. The intensity of the environment, steep learning curve, and lack of a structured orientation can lead to difficulties in role assimilation and feelings of disconnectedness. This led the authors to undertake an improvement project to develop an onboarding program for APNs and develop strategies to orient them to their role. The authors describe the program and discuss how it was perceived by the APNs. Program evaluation and suggestions for future nursing research are identified. PMID:21157242

  13. Determining the risks of magnetic resonance imaging at 1.5 tesla for patients with pacemakers and implantable cardioverter defibrillators.

    PubMed

    Cohen, Jennifer D; Costa, Heather S; Russo, Robert J

    2012-12-01

    Conventional pacemaker and implantable cardioverter-defibrillator product labeling currently cautions against exposure to magnetic resonance imaging (MRI). However, there is a growing clinical need for MRI, without an acceptable alternative imaging modality in many patients with cardiac devices. The purpose of this study was to determine the risk of MRI at 1.5 T for patients with cardiac devices by measuring the frequency of device failures and clinically relevant device parameter changes. Data from a single-center retrospective review of 109 patients with pacemakers and implantable cardioverter-defibrillators (the MRI group) who underwent 125 clinically indicated MRI studies were compared to data from a prospective cohort of 50 patients with cardiac devices who did not undergo MRI (the control group). In the MRI group, there were no deaths, device failures requiring generator or lead replacement, induced arrhythmias, losses of capture, or electrical reset episodes. Decreases in battery voltage of ?0.04 V occurred in 4%, pacing threshold increases of ?0.5 V in 3%, and pacing lead impedance changes of ?50 ? in 6%. Although there were statistically significant differences between the MRI and control groups for the mean change in pacing lead impedance (-6.2 23.9 vs 3.0 22.1 ?) and left ventricular pacing threshold (-0.1 0.3 vs 0.1 0.2 V), these differences were not clinically important. In conclusion, MRI in patients with cardiac devices resulted in no device or lead failures. A small number of clinically relevant changes in device parameter measurements were noted. However, these changes were similar to those in a control group of patients who did not undergo MRI. PMID:22921995

  14. Entrainment of coupled oscillators on regular networks by pacemakers

    NASA Astrophysics Data System (ADS)

    Radicchi, Filippo; Meyer-Ortmanns, Hildegard

    2006-03-01

    We study Kuramoto oscillators, driven by one pacemaker, on d -dimensional regular topologies with nearest neighbor interactions. We derive the analytical expressions for the common frequency in the case of phase-locked motion and for the critical frequency of the pacemaker, placed at an arbitrary position in the lattice, so that above the critical frequency no phase-locked motion is possible. We show that the mere change in topology from an open chain to a ring induces synchronization for a certain range of pacemaker frequencies and couplings, while keeping the other parameters fixed. Moreover, we demonstrate numerically that the critical frequency of the pacemaker decreases as a power of the linear size of the lattice with an exponent equal to the dimension of the system. This leads in particular to the conclusion that for infinite-dimensional topologies the critical frequency for having entrainment decreases exponentially with increasing size of the system, or, more generally, with increasing depth of the network, that is, the average distance of the oscillators from the pacemaker.

  15. Biasing the pacemaker in the behavioral theory of timing

    PubMed Central

    Bizo, Lewis A.; White, K. Geoffrey

    1995-01-01

    In the behavioral theory of timing, pacemaker rate is determined by overall rate of reinforcement. A two-alternative free-operant psychophysical procedure was employed to investigate whether pacemaker period was also sensitive to the differential rate of reinforcement. Responding on a left key during the first 25 s and on a right key during the second 25 s of a 50-s trial was reinforced at variable intervals, and variable-interval schedule values during the two halves of the trials were varied systematically. Responding on the right key during the first 25 s and on the left key during the second 25 s was not reinforced. Estimates of pacemaker period were derived from fits of a function predicted by the behavioral theory of timing to right-key response proportions in consecutive 5-s bins of the 50-s trial. Estimates of pacemaker period were shortest when the differential reinforcer rate most strongly favored right-key responses, and were longest when the differential reinforcer rate most strongly favored left-key responses. The results were consistent with the conclusion that pacemaker rate is influenced by relative reinforcer rate. PMID:16812769

  16. The neurochemical basis of photic entrainment of the circadian pacemaker

    NASA Technical Reports Server (NTRS)

    Rea, Michael A.; Buckley, Becky; Lutton, Lewis M.

    1992-01-01

    Circadian rhythmicity in mammals is controlled by the action of a light-entrainable hypothalamus, in association with two cell clusters known as the supra chiasmatic nuclei (SCN). In the absence of temporal environmental clues, this pacemaker continues to measure time by an endogenous mechanism (clock), driving biochemical, physiological, and behavioral rhythms that reflect the natural period of the pacemaker oscillation. This endogenous period usually differs slightly from 24 hours (i.e., circadian). When mammals are maintained under a 24 hour light-dark (LD) cycle, the pacemaker becomes entrained such that the period of the pacemaker oscillation matches that of the LD cycle. Potentially entraining photic information is conveyed to the SCN via a direct retinal projection, the retinohypothalamic tract (RHT). RHT neurotransmission is thought to be mediated by the release of excitatory amino acids (EAA) in the SCN. In support of this hypothesis, recent experiments using nocturnal rodents have shown that EAA antagonists block the effects of light on pacemaker-driven behavioral rhythms, and attenuate light induced gene expression in SCN cells. An understanding of the neurochemical basis of the photic entrainment process would facilitate the development of pharmacological strategies for maintaining synchrony among shift workers in environments, such as the Space Station, which provide unreliable or conflicting temporal photic clues.

  17. Are Electronic Cardiac Devices Still Evolving?

    PubMed Central

    Mabo, P.

    2014-01-01

    Summary Objectives The goal of this paper is to review some important issues occurring during the past year in Implantable devices. Methods First cardiac implantable device was proposed to maintain an adequate heart rate, either because the hearts natural pacemaker is not fast enough, or there is a block in the hearts electrical conduction system. During the last forty years, pacemakers have evolved considerably and become programmable and allow to configure specific patient optimum pacing modes. Various technological aspects (electrodes, connectors, algorithms diagnosis, therapies, ) have been progressed and cardiac implants address several clinical applications: management of arrhythmias, cardioversion / defibrillation and cardiac resynchronization therapy. Results Observed progress was the miniaturization of device, increased longevity, coupled with efficient pacing functions, multisite pacing modes, leadless pacing and also a better recognition of supraventricular or ventricular tachycardias in order to deliver appropriate therapy. Subcutaneous implant, new modes of stimulation (leadless implant or ultrasound lead), quadripolar lead and new sensor or new algorithm for the hemodynamic management are introduced and briefly described. Each times, the main result occurring during the two past years are underlined and repositioned from the history, remaining limitations are also addressed. Conclusion Some important technological improvements were described. Nevertheless, news trends for the future are also considered in a specific session such as the remote follow-up of the patient or the treatment of heart failure by neuromodulation. PMID:25123732

  18. [Future of implantable electrical cardiac devices].

    PubMed

    Daubert, Jean-Claude; Behaghel, Albin; Leclercq, Christophe; Mabo, Philippe

    2015-03-01

    Major improvements in implantable electrical cardiac devices have been made during the last two decades, notably with the advent of automatic internal defibrillation (ICD) to prevent sudden arrhythmic death, and cardiac resynchronisation (CRT) to treat the discoordinated failing heart. They now constitute a major therapeutic option and may eventually supersede drug therapy. The coming era will be marked by a technological revolution, with improvements in treatment delivery, safety and efficacy, and an expansion of clinical indications. Leadless technologyfor cardiac pacemakers and defibrillators is already in the pipeline, endovascular leads currently being responsible for most long-term complications (lead failure, infection, vein thrombosis, etc.). Miniaturized pacemakers based on nanotechnology can now be totally implanted inside the right ventricle through the transvenous route, thus eliminating leads, pockets and scarring In the same way, totally subcutaneous ICD systems are now available, although they are currently only capable of delivering shocks, without pacing (including antitachycardia pacing). In CRT optimised delivery is important to improve clinical responses and to reduce the non-response rate (around 30 % with current technology). Endocardial left ventricular pacing could be a solution if it can be achieved at an acceptable risk. Multisite ventricular pacing is an alternative. Besides CRT neuromodulation, especially by vagal stimulation, is another important field of device researchfor heart failure. Preliminary clinical results are encouraging. PMID:26427291

  19. Changes of autonomic cardiac profile after a 3-week integrated body weight reduction program in severely obese patients.

    PubMed

    Facchini, M; Malfatto, G; Sala, L; Silvestri, G; Fontana, P; Lafortuna, C; Sartorio, A

    2003-02-01

    The autonomic control of the heart is abnormal in obese subjects due to a prevalence of sympathetic over parasympathetic limb of the autonomic balance. We evaluated the effects of a short-term (3 weeks) integrated body weight reduction program (consisting of energy restricted diet and high-intensity exercise training) on heart rate variability (HRV) in severely obese, normotensive patients. The HRV was evaluated both in the time and frequency domain over a 18-hour Holter recording period obtained before and at the end of the third week. Three-week body weight reduction program reduced BMI (from 41.4 +/- 4.6 to 39.5 +/- 4.3 kg/m2, -4.6%, p<0.0001) and heart rate (from 77.8 +/- 8.6 to 73.6 +/- 8.7 b/min, p=0.0003). Significant changes in the autonomic profile were observed both in the time and frequency domain (SD of RR interval, SDRR: +16.1%; mean squared successive difference: (MSSD) +16.7%; percentage of RR intervals differing more than 50 msec from the preceding one, pNN50: +31.8%; low frequency oscillation, LF: +17.1%; high frequency oscillation, HF: +/- 18.2%). In conclusion, this study demonstrates that a short-term, integrated body weight reduction program is able to favorably modify the autonomic profile in a population of normotensive, severely obese subjects. The reduction of heart rate and the increase in parasympathetic activity may consistently contribute to a reduction of the risk of cardiovascular morbidity and of sudden cardiac death, still high in this patients' group. PMID:12739741

  20. Exercise Programming for Cardiacs--A New Direction for Physical Therapists.

    ERIC Educational Resources Information Center

    Gutin, Bernard

    This speech begins with the presentation of a conceptual scheme of the physical working capacity of a person starting a training program. The scheme shows that after exercise, when recovery begins and sufficient time elapses, the individual recovers and adapts to a level of physical working capacity which is higher than his starting level. From…

  1. Flexibility and Strength Measures in Children Participating in a Cardiac Rehabilitation Exercise Program.

    ERIC Educational Resources Information Center

    Koch, Barbara M.; And Others

    1988-01-01

    A 12-week structured rehabilitation program featuring warm-up exercises, increased aerobic exercise, cool down, and home-based continuation of exercise helped 12 children with surgically corrected congenital heart disease improve lower extremity strength and flexibility. (Author/CB)

  2. Reprogramming of implanted pacemaker following external defibrillation.

    PubMed

    Barold, S S; Ong, L S; Scovil, J; Heinle, R A; Wright, T

    1978-10-01

    This report describes reprogramming of a pulse generator consequent to cardiac defibrillation. Analysis of the explanted pulse generator revealed normal function. We tested the electrical properties of several defibrillators and our studies suggest that erratic electrostatic discharges at the time of paddle application before defibrillation may create a signal sequence capable of reprogramming the particular pulse generator by activating either the reed switch or internal electronics. PMID:95645

  3. Short-term inspiratory muscle training potentiates the benefits of aerobic and resistance training in patients undergoing CABG in phase II cardiac rehabilitation program

    PubMed Central

    Hermes, Brbara Maria; Cardoso, Dannuey Machado; Gomes, Tiago Jos Nardi; dos Santos, Tamires Daros; Vicente, Marlia Severo; Pereira, Srgio Nunes; Barbosa, Viviane Acunha; de Albuquerque, Isabella Martins

    2015-01-01

    Objective To investigate the efficiency of short-term inspiratory muscle training program associated with combined aerobic and resistance exercise on respiratory muscle strength, functional capacity and quality of life in patients who underwent coronary artery bypass and are in the phase II cardiac rehabilitation program. Methods A prospective, quasi-experimental study with 24 patients who underwent coronary artery bypass and were randomly assigned to two groups in the Phase II cardiac rehabilitation program: inspiratory muscle training program associated with combined training (aerobic and resistance) group (GCR + IMT, n=12) and combined training with respiratory exercises group (GCR, n=12), over a period of 12 weeks, with two sessions per week. Before and after intervention, the following measurements were obtained: maximal inspiratory and expiratory pressures (PImax and PEmax), peak oxygen consumption (peak VO2) and quality of life scores. Data were compared between pre- and post-intervention at baseline and the variation between the pre- and post-phase II cardiac rehabilitation program using the Student's t-test, except the categorical variables, which were compared using the Chi-square test. Values of P<0.05 were considered statistically significant. Results Compared to GCR, the GCR + IMT group showed larger increments in PImax (P<0.001), PEmax (P<0.001), peak VO2 (P<0.001) and quality of life scores (P<0.001). Conclusion The present study demonstrated that the addition of inspiratory muscle training, even when applied for a short period, may potentiate the effects of combined aerobic and resistance training, becoming a simple and inexpensive strategy for patients who underwent coronary artery bypass and are in phase II cardiac rehabilitation.

  4. Bursting in Cellular Automata and Cardiac Arrhythmias

    NASA Astrophysics Data System (ADS)

    Bub, Gil; Shrier, Alvin; Glass, Leon

    2013-01-01

    The mechanisms underlying the initiation and continuation of abnormal cardiac arrhythmias are incompletely understood. In this chapter, we summarize work that shows how simple cellular automata models of excitable media can display a range of interesting dynamical behavior including spontaneous bursts of reentrant spiral activity. Since the model incorporates basic physiological properties of excitability, heterogeneity, localized pacemakers, and fatigue in a schematic way, the model captures generic physiological dynamics that should be broadly observed in experimental and clinical settings as well as in more realistic mathematical models.

  5. Interference with the pacemakers of two workers at electricity substations.

    PubMed Central

    Butrous, G S; Bexton, R S; Barton, D G; Male, J C; Camm, A J

    1983-01-01

    Pacemaker function was tested in two electricity substation workers exposed to high tension electric fields. High intensity electric fields induced reversion to the interference mode, producing in one case competitive rhythm and in the other inappropriately slow pacing which resulted in asymptomatic pauses of up to 2.5 s. A suit designed to shield the body from the effects of high intensity electric fields was tried and proved to be effective in protecting the pacemaker, allowing it to function normally in the substations. Images PMID:6626476

  6. Experimental evidence of a chaotic region in a neural pacemaker

    NASA Astrophysics Data System (ADS)

    Gu, Hua-Guang; Jia, Bing; Chen, Guan-Rong

    2013-03-01

    In this Letter, we report the finding of period-adding scenarios with chaos in firing patterns, observed in biological experiments on a neural pacemaker, with fixed extra-cellular potassium concentration at different levels and taken extra-cellular calcium concentration as the bifurcation parameter. The experimental bifurcations in the two-dimensional parameter space demonstrate the existence of a chaotic region interwoven with the periodic region thereby forming a period-adding sequence with chaos. The behavior of the pacemaker in this region is qualitatively similar to that of the Hindmarsh-Rose neuron model in a well-known comb-shaped chaotic region in two-dimensional parameter spaces.

  7. Interference with the pacemakers of two workers at electricity substations.

    PubMed

    Butrous, G S; Bexton, R S; Barton, D G; Male, J C; Camm, A J

    1983-11-01

    Pacemaker function was tested in two electricity substation workers exposed to high tension electric fields. High intensity electric fields induced reversion to the interference mode, producing in one case competitive rhythm and in the other inappropriately slow pacing which resulted in asymptomatic pauses of up to 2.5 s. A suit designed to shield the body from the effects of high intensity electric fields was tried and proved to be effective in protecting the pacemaker, allowing it to function normally in the substations. PMID:6626476

  8. Cardiac Sarcoidosis

    MedlinePLUS

    ... Ventricular tachycardia often requires placement of an internal cardiac defibrillator (ICD). What do we do at National Jewish Health? We provide comprehensive cardiology evaluation and consultation and non-invasive cardiac testing. We evaluate and treat heart problems such ...

  9. Managing heart block after transcatheter aortic valve implantation: from monitoring to device selection and pacemaker indications.

    PubMed

    Urena, Marina; Rods-Cabau, Josep

    2015-09-01

    The introduction of the so-called newer-generation transcatheter aortic valve implantation (TAVI) devices has led to a dramatic reduction in the incidence of complications associated with the procedure. However, preliminary data suggest that conduction abnormalities (particularly new-onset atrioventricular block and left bundle branch block) remain a frequent complication post TAVI. Although inconsistencies across studies are apparent, new-onset conduction abnormalities post TAVI may be associated with higher incidences of mortality, sudden cardiac death and left ventricular dysfunction. Strategies intended both to reduce the risk and to improve the management of such complications are clearly warranted. In fact, the indication and timing of permanent pacemaker implantation are frequently individualised according to centre and/or operator preference. Currently, studies assessing the impact of these complications and the optimal indications for permanent cardiac pacing are underway. In this article, we review the data available on the incidence and impact of conduction disturbances following TAVI, and propose a strategy for the management of such complications. PMID:26384171

  10. Transcatheter aortic valve replacement: establishing a comprehensive program model for hybrid cardiac catheterization laboratories in the Department of Veterans Affairs.

    PubMed

    Speiser, Bernadette; Dutra-Brice, Cynthia

    2014-01-01

    Aortic valve disease, especially aortic stenosis, becomes progressively debilitating and carries a high mortality risk if it is categorized as severe and symptomatic (J Thorac Cardiovas Surg. 2012;144(3):e29-e84). In the past, the only treatment for aortic stenosis was surgical aortic valve replacement. Surgical treatment may require several hours of cardioplegia, and if the patient has comorbidities, such as renal failure or chronic obstructive pulmonary disease, their operative mortality percentage increases.In 2011, the US Food and Drug Administration approved the use of a transcatheter aortic valve replacement (TAVR) procedure for patients who were deemed high risk or inoperative for the routine surgical aortic valve replacement surgery. More than 20,?000 TAVRs have been performed in patients worldwide since 2002 when Dr Alain Cribier performed the first-in-man TAVR (Arch Cardiovasc Dis. 2012;105(3):145-152). The Edwards Lifesciences SAPIEN XT valve and the Medtronic CoreValve are commercially available.The clinical findings and economic statistic have supported the expansion of the TAVR procedure. However, there has been considerable controversy over where the procedure is to occur and who is directly responsible for directing the TAVR care. This debate has identified barriers to the implementation of a TAVR program. The operating rooms and a cardiac catheterization laboratory are underprepared for the hybrid valve replacement therapy. Because of the barriers identified, the Department of Veterans Affairs determined a need for a systematic approach to review the programs that applied for this structural heart disease program. A centralized team was developed to ensure room readiness and staff competency. The use of the Health Failure Mode and Effects Analysis can define high-risk clinical processes and conduct a hazard analysis. Worksheets can show potential failure modes and their probabilities, along with actions and outcome measures, team collaboration, extensive screening, and selection process. The TAVR program begins implementation with data entry with each case into CART-CL (Cardiovascular Assessment, Reporting and Tracking System for Cath Labs, Veteran Administration database for interventional cardiology procedures). If an untoward event occurs, within 24 hours the CART-CL Quality Assessment Team is activated to begin the review process. This provides real-time review and feedback to the local facility in an expeditious manner. Cardiac catheterization laboratories have been inundated with rapidly changing technological advances in the past decade. The era for structural heart repair is rapidly mobilizing from a surgical/operating room setting to a transcatheter/hybrid catheterization laboratory suite. The use of the new hybrid catheterization laboratories will continue to expand as the approval of future transcatheter therapies evolve. Editor's note: Due to the volume of important information presented in each table, only the first table is included in the print version of the article, however, all tables may be viewed in their entirety free of charge on the online version of this article: http://journals.lww.com/dccnjournal/pages/default.aspx. PMID:25144213

  11. [Cardiac Rehabilitation 2015].

    PubMed

    Hoffmann, Andreas

    2015-11-25

    The goals of cardiac rehabilitation are (re-)conditioning and secondary prevention in patients with heart disease or an elevated cardiovascular risk profile. Rehabilitation is based on motivation through education, on adapted physical activity, instruction of relaxation techniques, psychological support and optimized medication. It is performed preferably in groups either in outpatient or inpatient settings. The Swiss working group on cardiac rehabilitation provides a network of institutions with regular quality auditing. Positive effects of rehabilitation programs on mortality and morbidity have been established by numerous studies. Although a majority of patients after cardiac surgery are being referred to rehabilitation, these services are notoriously underused after catheter procedures. PMID:26602848

  12. Diabetes mellitus activates fetal gene program and intensifies cardiac remodeling and oxidative stress in aged spontaneously hypertensive rats

    PubMed Central

    2013-01-01

    Background The combination of systemic arterial hypertension and diabetes mellitus (DM) induces greater cardiac remodeling than either condition alone. However, this association has been poorly addressed in senescent rats. Therefore, this study aimed to analyze the influence of streptozotocin-induced DM on ventricular remodeling and oxidative stress in aged spontaneously hypertensive rats (SHR). Methods Fifty 18 month old male SHR were divided into two groups: control (SHR, n = 25) and diabetic (SHR-DM, n = 25). DM was induced by streptozotocin (40 mg/kg, i.p.). After nine weeks, the rats underwent echocardiography and myocardial functional study in left ventricular (LV) isolated papillary muscle preparations. LV samples were obtained to measure myocyte diameters, interstitial collagen fraction, and hydroxyproline concentration. Gene expression of atrial natriuretic peptide (ANP) and α- and β-myosin heavy chain (MyHC) isoforms was evaluated by RT-PCR. Serum oxidative stress was assessed by measuring lipid hydroperoxide concentration and superoxide dismutase and glutathione peroxidase activities. Statistics: Student’s t test or Mann-Whitney test, p < 0.05. Results SHR-DM presented higher blood glucose (487 ± 29 vs. 89.1 ± 21.1 mg/dL) and lower body weight (277 ± 26 vs. 339 ± 38 g). Systolic blood pressure did not differ between groups. Echocardiography showed LV and left atrial dilation, LV diastolic and relative wall thickness decrease, and LV systolic and diastolic function impairment in SHR-DM. Papillary muscle study showed decreased myocardial contractility and contractile reserve in SHR-DM. Myocyte diameters and myocardial interstitial collagen fraction and hydroxyproline concentration did not differ between groups. Increased serum pro-oxidant activity and gene expression of ANP and β/α-MyHC ratio were observed in DM. Conclusion Diabetes mellitus induces cardiac dilation and functional impairment, increases oxidative stress and activates fetal gene program in aged spontaneously hypertensive rats. PMID:24134628

  13. Same-day transfer of patients to the cardiac telemetry unit after surgery: the Rapid after Bypass Back into Telemetry (RABBIT) program.

    PubMed

    Sakallaris, B R; Halpin, L S; Knapp, M; Sheridan, M J

    2000-04-01

    Early data from this project suggest that the RABBIT program fulfilled the process improvement goals of decreasing costs of cardiac surgery and maintaining high quality. Decreased cost was achieved by decreasing time to extubation and decreasing length of stay in the ICU and the total length of stay in the hospital. The cost savings were achieved without compromising the quality of care, which was assessed by measuring rates of readmission to the ICU and to the hospital and by surveying patients about their level of satisfaction. The success of the RABBIT program can be attributed to several factors. First, members of the cardiac surgery quality improvement team worked well together to solve problems and overcome obstacles, particularly after the pilot program. Second, naming the program helped to motivate staff, physicians, and patients. Outcome data was shared with the staff quarterly, and successes were celebrated. Finally, the use of a facilitator early in the process to establish the process with the surgeons and the staff was invaluable. Opportunities for continued improvement include resolving operational difficulties related to availability of beds and staffing, continuing work with physicians in changing practice patterns, increasing efficiency in scheduling operating rooms, and adjusting the preoperative education provided to patients and their families about the length of stay to expect. Quarterly outcome analysis continues, with reports to the cardiac surgery quality improvement team. The team continues to explore creative solutions to the aforementioned issues, as the goal of having 25% of patients who undergo cardiac surgery be transferred to the CTU on the day of surgery has remained elusive. PMID:11873752

  14. Starting a transradial vascular access program in the cardiac catheterization laboratory.

    PubMed

    Cohen, Mauricio G; Alfonso, Carlos

    2009-08-01

    Over the past 20 years, since the first reports, transradial vascular access for coronary angiography and intervention has flourished in many countries while still accounting for less than 2% of all cases performed in the United States due, in part, to difficulties in introducing change to established practice patterns. The benefits of transradial access include decreased bleeding risk, increased patient comfort, lessened post-procedure nursing workload, and decreased hospital costs. A learning curve to gain the specific set of skills for transradial access has been well described. Although published data suggest that 100-200 cases are necessary to become proficient, the learning curve is likely highly individual, and some operators may become proficient sooner. The equipment to start a transradial program is minimal and includes modified sheaths and catheters. Patients with morbid obesity, peripheral vascular disease, and anticoagulation clearly benefit from this approach. To establish a transradial program and offer the benefits of this approach to most patients, a dedicated interventionalist must incorporate peers and hospital staff to create a multidisciplinary team. PMID:19734569

  15. Regulation of a human cardiac actin gene introduced into rat L6 myoblasts suggests a defect in their myogenic program.

    PubMed Central

    Hickey, R; Skoultchi, A; Gunning, P; Kedes, L

    1986-01-01

    The rat myogenic cell line L6E9 induces skeletal but not cardiac alpha-actin mRNA upon fusion to form myotubes. However, when a human cardiac alpha-actin gene was introduced into L6E9 myoblasts, differentiation of the cells led to the accumulation of human gene transcripts in parallel with those derived from the endogenous skeletal alpha-actin gene. This result demonstrates that factors which direct rat myogenesis can regulate a muscle gene from another species and that the L6E9 cells may have a defect in their ability to activate endogenous cardiac actin gene expression. Images PMID:3785229

  16. [Practical questions around individual with a pacemaker or an implantable cardioverter defibrillator].

    PubMed

    Manaouil, Cécile; Fantoni, Sophie; Montpellier, Dominique; Tordjman, Eric; Jarde, Olivier

    2012-07-01

    An individual with a pacemaker can ask his GP for information about potential problems associated with the device. Should a pacemaker continue to be used by end-of-life patients? Should a pacemaker be stopped in a limited care situation? What precautions should be taken when treating a patient with a pacemaker? Pacemakers and implantable defibrillators are sensitive to electromagnetic interference (EMI). Medically, MRIs are theoretically contraindicated, even though examinations could be performed without a major problem, and special precautions should be taken when using an electrosurgical cutter or radiotherapy. In case of death, a doctor or embalmer must remove the patient's pacemaker due to its risk of explosion during cremation. Doctors who sign cremation forms have a legal obligation to provide such information. It may affect an employee's ability to work. Are there some professions that are not well suited for individuals with a pacemaker? PMID:22138293

  17. Cardiac cell: a biological laser?

    PubMed

    Chorvat, D; Chorvatova, A

    2008-04-01

    We present a new concept of cardiac cells based on an analogy with lasers, practical implementations of quantum resonators. In this concept, each cardiac cell comprises a network of independent nodes, characterised by a set of discrete energy levels and certain transition probabilities between them. Interaction between the nodes is given by threshold-limited energy transfer, leading to quantum-like behaviour of the whole network. We propose that in cardiomyocytes, during each excitation-contraction coupling cycle, stochastic calcium release and the unitary properties of ionic channels constitute an analogue to laser active medium prone to "population inversion" and "spontaneous emission" phenomena. This medium, when powered by an incoming threshold-reaching voltage discharge in the form of an action potential, responds to the calcium influx through L-type calcium channels by stimulated emission of Ca2+ ions in a coherent, synchronised and amplified release process known as calcium-induced calcium release. In parallel, phosphorylation-stimulated molecular amplification in protein cascades adds tuneable features to the cells. In this framework, the heart can be viewed as a coherent network of synchronously firing cardiomyocytes behaving as pulsed laser-like amplifiers, coupled to pulse-generating pacemaker master-oscillators. The concept brings a new viewpoint on cardiac diseases as possible alterations of "cell lasing" properties. PMID:18191016

  18. Evaluation of a self-management patient education program for patients with chronic heart failure undergoing inpatient cardiac rehabilitation: study protocol of a cluster randomized controlled trial

    PubMed Central

    2013-01-01

    Background Chronic heart failure requires a complex treatment regimen on a life-long basis. Therefore, self-care/self-management is an essential part of successful treatment and comprehensive patient education is warranted. However, specific information on program features and educational strategies enhancing treatment success is lacking. This trial aims to evaluate a patient-oriented and theory-based self-management educational group program as compared to usual care education during inpatient cardiac rehabilitation in Germany. Methods/Design The study is a multicenter cluster randomized controlled trial in four cardiac rehabilitation clinics. Clusters are patient education groups that comprise HF patients recruited within 2 weeks after commencement of inpatient cardiac rehabilitation. Cluster randomization was chosen for pragmatic reasons, i.e. to ensure a sufficient number of eligible patients to build large-enough educational groups and to prevent contamination by interaction of patients from different treatment allocations during rehabilitation. Rehabilitants with chronic systolic heart failure (n = 540) will be consecutively recruited for the study at the beginning of inpatient rehabilitation. Data will be assessed at admission, at discharge and after 6 and 12 months using patient questionnaires. In the intervention condition, patients receive the new patient-oriented self-management educational program, whereas in the control condition, patients receive a short lecture-based educational program (usual care). The primary outcome is patients’ self-reported self-management competence. Secondary outcomes include behavioral determinants and self-management health behavior (symptom monitoring, physical activity, medication adherence), health-related quality of life, and treatment satisfaction. Treatment effects will be evaluated separately for each follow-up time point using multilevel regression analysis, and adjusting for baseline values. Discussion This study evaluates the effectiveness of a comprehensive self-management educational program by a cluster randomized trial within inpatient cardiac rehabilitation in Germany. Furthermore, subgroup-related treatment effects will be explored. Study results will contribute to a better understanding of both the effectiveness and mechanisms of a self-management group program as part of cardiac rehabilitation. Trial registration German Clinical Trials Register: DRKS00004841; WHO International Clinical Trials: = DRKS00004841 PMID:23968340

  19. Differentially Timed Extracellular Signals Synchronize Pacemaker Neuron Clocks

    PubMed Central

    Collins, Ben; Kaplan, Harris S.; Cavey, Matthieu; Lelito, Katherine R.; Bahle, Andrew H.; Zhu, Zhonghua; Macara, Ann Marie; Roman, Gregg; Shafer, Orie T.; Blau, Justin

    2014-01-01

    Synchronized neuronal activity is vital for complex processes like behavior. Circadian pacemaker neurons offer an unusual opportunity to study synchrony as their molecular clocks oscillate in phase over an extended timeframe (24 h). To identify where, when, and how synchronizing signals are perceived, we first studied the minimal clock neural circuit in Drosophila larvae, manipulating either the four master pacemaker neurons (LNvs) or two dorsal clock neurons (DN1s). Unexpectedly, we found that the PDF Receptor (PdfR) is required in both LNvs and DN1s to maintain synchronized LNv clocks. We also found that glutamate is a second synchronizing signal that is released from DN1s and perceived in LNvs via the metabotropic glutamate receptor (mGluRA). Because simultaneously reducing Pdfr and mGluRA expression in LNvs severely dampened Timeless clock protein oscillations, we conclude that the master pacemaker LNvs require extracellular signals to function normally. These two synchronizing signals are released at opposite times of day and drive cAMP oscillations in LNvs. Finally we found that PdfR and mGluRA also help synchronize Timeless oscillations in adult s-LNvs. We propose that differentially timed signals that drive cAMP oscillations and synchronize pacemaker neurons in circadian neural circuits will be conserved across species. PMID:25268747

  20. Pacemakers and Implantable Defibrillators - Multiple Languages: MedlinePlus

    MedlinePLUS

    ... PDF Health Information Translations Spanish (español) Marcapasos y desfibrilador implantable Ukrainian (Українська) Pacemaker Електрокардіостимулятор - Українська (Ukrainian) Bilingual ...

  1. 21 CFR 870.3640 - Indirect pacemaker generator function analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Indirect pacemaker generator function analyzer. 870.3640 Section 870.3640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices §...

  2. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker electrode function tester. 870.3720 Section 870.3720 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3720...

  3. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pacemaker electrode function tester. 870.3720 Section 870.3720 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3720...

  4. 21 CFR 870.3600 - External pacemaker pulse generator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false External pacemaker pulse generator. 870.3600 Section 870.3600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3600...

  5. 21 CFR 870.3640 - Indirect pacemaker generator function analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Indirect pacemaker generator function analyzer. 870.3640 Section 870.3640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices §...

  6. 21 CFR 870.3640 - Indirect pacemaker generator function analyzer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Indirect pacemaker generator function analyzer. 870.3640 Section 870.3640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices §...

  7. 21 CFR 870.3600 - External pacemaker pulse generator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false External pacemaker pulse generator. 870.3600 Section 870.3600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3600...

  8. 21 CFR 870.3610 - Implantable pacemaker pulse generator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Implantable pacemaker pulse generator. 870.3610 Section 870.3610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3610...

  9. 21 CFR 870.3630 - Pacemaker generator function analyzer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker generator function analyzer. 870.3630 Section 870.3630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3630...

  10. 21 CFR 870.3640 - Indirect pacemaker generator function analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Indirect pacemaker generator function analyzer. 870.3640 Section 870.3640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices §...

  11. 21 CFR 870.1750 - External programmable pacemaker pulse generator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false External programmable pacemaker pulse generator. 870.1750 Section 870.1750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices §...

  12. 21 CFR 870.3600 - External pacemaker pulse generator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false External pacemaker pulse generator. 870.3600 Section 870.3600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3600...

  13. 21 CFR 870.3630 - Pacemaker generator function analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pacemaker generator function analyzer. 870.3630 Section 870.3630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3630...

  14. 21 CFR 870.3710 - Pacemaker repair or replacement material.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pacemaker repair or replacement material. 870.3710 Section 870.3710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3710...

  15. 21 CFR 870.3630 - Pacemaker generator function analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pacemaker generator function analyzer. 870.3630 Section 870.3630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3630...

  16. 21 CFR 870.1750 - External programmable pacemaker pulse generator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false External programmable pacemaker pulse generator. 870.1750 Section 870.1750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices §...

  17. 21 CFR 870.3630 - Pacemaker generator function analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pacemaker generator function analyzer. 870.3630 Section 870.3630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3630...

  18. 21 CFR 870.3600 - External pacemaker pulse generator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false External pacemaker pulse generator. 870.3600 Section 870.3600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3600...

  19. 21 CFR 870.3710 - Pacemaker repair or replacement material.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pacemaker repair or replacement material. 870.3710 Section 870.3710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3710...

  20. 21 CFR 870.1750 - External programmable pacemaker pulse generator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false External programmable pacemaker pulse generator. 870.1750 Section 870.1750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices §...

  1. 21 CFR 870.1750 - External programmable pacemaker pulse generator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false External programmable pacemaker pulse generator. 870.1750 Section 870.1750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices §...

  2. 21 CFR 870.3640 - Indirect pacemaker generator function analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Indirect pacemaker generator function analyzer. 870.3640 Section 870.3640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices §...

  3. 21 CFR 870.3710 - Pacemaker repair or replacement material.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker repair or replacement material. 870.3710 Section 870.3710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3710...

  4. 21 CFR 870.3600 - External pacemaker pulse generator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false External pacemaker pulse generator. 870.3600 Section 870.3600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3600...

  5. 21 CFR 870.3710 - Pacemaker repair or replacement material.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pacemaker repair or replacement material. 870.3710 Section 870.3710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3710...

  6. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pacemaker electrode function tester. 870.3720 Section 870.3720 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3720...

  7. 21 CFR 870.3610 - Implantable pacemaker pulse generator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Implantable pacemaker pulse generator. 870.3610 Section 870.3610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3610...

  8. 21 CFR 870.3630 - Pacemaker generator function analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pacemaker generator function analyzer. 870.3630 Section 870.3630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3630...

  9. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pacemaker electrode function tester. 870.3720 Section 870.3720 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3720...

  10. 21 CFR 870.3610 - Implantable pacemaker pulse generator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Implantable pacemaker pulse generator. 870.3610 Section 870.3610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3610...

  11. 21 CFR 870.3710 - Pacemaker repair or replacement material.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pacemaker repair or replacement material. 870.3710 Section 870.3710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3710...

  12. 21 CFR 870.1750 - External programmable pacemaker pulse generator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false External programmable pacemaker pulse generator. 870.1750 Section 870.1750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices §...

  13. 21 CFR 870.3610 - Implantable pacemaker pulse generator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... asynchronous devices implanted in the human body. (b) Classification. Class III (premarket approval). (c) Date... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implantable pacemaker pulse generator. 870.3610 Section 870.3610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  14. 21 CFR 870.3610 - Implantable pacemaker pulse generator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... asynchronous devices implanted in the human body. (b) Classification. Class III (premarket approval). (c) Date... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Implantable pacemaker pulse generator. 870.3610 Section 870.3610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  15. Bifurcations in a nonlinear model of the baroreceptor-cardiac reflex

    NASA Astrophysics Data System (ADS)

    Seidel, H.; Herzel, H.

    1998-04-01

    We investigate the dynamic properties of a nonlinear model of the human cardio-baroreceptor control loop. As a new feature we use a phase effectiveness curve to describe the experimentally well-known phase dependency of the cardiac pacemaker's sensitivity to neural activity. We show that an increase of sympathetic time delays leads via a Hopf bifurcation to sustained heart rate oscillations. For increasing baroreflex sensitivity or for repetitive vagal stimulation we observe period-doubling, toroidal oscillations, chaos, and entrainment between the rhythms of the heart and the control loop. The bifurcations depend crucially on the involvement of the cardiac pacemaker's phase dependency. We compare the model output with experimental data from electrically stimulated anesthetized dogs and discuss possible implications for cardiac arrhythmias.

  16. The Acute Effects of Changes to AV Delay on Blood Pressure and Stroke Volume: Potential Implications for Design of Pacemaker Optimization Protocols

    PubMed Central

    Manisty, Charlotte H.; Al-Hussaini, Ali; Unsworth, Beth; Baruah, Resham; Pabari, Punam A.; Mayet, Jamil; Hughes, Alun D.; Whinnett, Zachary I.; Francis, Darrel P.

    2012-01-01

    Background Atrioventricular (AV) delay optimization of biventricular pacemakers (cardiac resynchronization therapy, CRT) may maximise hemodynamic benefit, but consumes specialist time to conduct echocardiographically. Non-invasive blood pressure monitoring is a potentially-automatable alternative, but it is unknown whether it gives the same information, and similar precision (signal-to-noise ratio). Moreover, the immediate blood pressure increment on optimization has been reported to decay away: it is unclear whether this is the result of an (undesirable) fall in stroke volume or a (desirable) compensatory relief of peripheral vasoconstriction. Methods and Results To discriminate between these alternative mechanisms, we measured simultaneous beat-to-beat stroke volume (flow) using Doppler echocardiography, and blood pressure (BP) using finger photoplethysmography, during and after atrioventricular delay changes from 40 to 120 ms in 19 subjects with cardiac pacemakers. BP and stroke volume both increased immediately (p<0.001, within one heartbeat). BP showed a clear decline a few seconds later (average rate ?0.65mmHg/beat, r=0.95 [95% CI 0.86 to 0.98]); in contrast, stroke volume did not decline (p=0.87). The immediate BP increment correlated strongly with the stroke volume increment (r=0.74, p<0.001). Signal-to-noise ratio was threefold better for BP than stroke volume (6.83.5 versus 2.31.4, p<0.001). Conclusions Improving atrioventricular delay immediately increases blood pressure, but the effect begins to decay within a few seconds. Reassuringly this is due to compensatory vasodilatation rather than reduction in cardiac function. Pacemaker optimization will never be reliable unless there is adequate signal-to-noise ratio. Using BP rather than Doppler minimises noise. The early phase before vascular compensation has the richest signal lode. PMID:22095639

  17. Evaluation of a rechargeable pacemaker system.

    PubMed

    Stertzer, S H; DePasquale, N P; Cohn, L J; Bruno, M S

    1978-04-01

    A rechargeable-demand nickel-cadmium pulse generator for permanent transvenous cardiac pacing was evaluated in 66 patients. During a cumulative follow-up period of 2,333 patient months (194.4 patient years), failure of the pacing circuit occurred in 3 patients at 21, 25, and 27 months, respectively. Nine patients had difficulty accepting the recharging concept and, in 3 of these patients, it became necessary to replace the rechargeable generator with a conventional energy source. The overall failure rate of approximately 3% per year (including the 3 patients in whom it was necessary to remove the generator because of failure to recharge properly), coupled with the inconvenience of recharging, limits the usefulness of the rechargeable system compared to the newer lithium-powered generator. PMID:83632

  18. Absent right and persistent left superior vena cava: troubleshooting during a challenging pacemaker implant: a case report

    PubMed Central

    2014-01-01

    Background Venous anomalies of the thorax can occur in isolation or in association with complex congenital heart disease. The incidence of an absent right superior vena cava in the setting of a persistent left superior vena cava is very rare in the general population with only a dozen cases documented in the medical literature. Such venous anomalies can make for very challenging electronic cardiac device implantation. We report our challenging dual chamber pacemaker implant in a patient with such complex anatomy and focus on our implantation technique that helped achieve adequate lead positioning. Case presentation A 73-year-old Caucasian female with degenerative complete heart block presented for dual chamber permanent pacemaker implant. Lead implantation was very challenging due to abnormal and rare vena cava anatomy; a persistent left superior vena cava drained directly into the coronary sinus and the right brachiocephalic vein drained directly into the left persistent superior vena cava as the patient had an absent right superior vena cava . Adequate right ventricular lead positioning was achieved following numerous lead-stylet manipulations and careful looping in the atria to redirect its trajectory to the ventricular apex. Conclusion Abnormal superior vena cava development is uncommon and can lead to technical challenges when venous access is required during various interventional procedures. Pre-operative imaging can help identify such challenging anatomy allowing appropriate operative planning; careful patient selection is warranted for venography given the risk of contrast nephrotoxicity. PMID:25047923

  19. Extended Application of the Hybrid Procedure in Neonates with Left-Sided Obstructive Lesions in an Evolving Cardiac Program.

    PubMed

    Taqatqa, Anas; Diab, Karim A; Stuart, Christopher; Fogg, Louis; Ilbawi, Michel; Awad, Sawsan; Caputo, Massimo; Amin, Zahid; Abdulla, Ra-Id; Kenny, Damien; Hijazi, Ziyad M

    2016-03-01

    The hybrid approach to management of hypoplastic left heart syndrome (HLHS) was developed as an alternative to neonatal Norwood surgery, providing a less invasive initial palliation for HLHS. We describe our experience in extending the concept of the hybrid procedure to palliate neonates with anatomically compromised systemic arterial blood flow in a variety of congenital cardiac anomalies and supporting its application as first-line palliation in centers developing their HLHS programs. Retrospective review of patients undergoing therapy for HLHS at a single institution from June 2008 to December 2014 was performed. Subject demographics, clinical and procedural data, along with follow-up, were collected. Thirteen patients had initial hybrid palliation for HLHS during the time frame indicated at a median age of 8 days (range 1-29 days) and median weight of 3.4 kg (range 2.4-4.6 kg). Diagnoses included typical HLHS (n = 6), right-dominant unbalanced atrioventricular septal defect with arch hypoplasia (n = 4), double outlet right ventricle [subpulmonic VSD (n = 1) and intact ventricular septum (n = 1)] with hypoplastic transverse aortic arch and borderline left ventricular dimensions. Standard approach with bilateral pulmonary artery banding and ductal stenting was carried out in all thirteen patients. Two patients required two ductal stents at the time of index procedure. There were no intraprocedural complications. Median intubation length post-procedure was 4 days (range 1-74 days). Median hospital stay post-procedure was 47 days (range 15-270 days). The overall mortality rate on follow-up through comprehensive stage 2 over the 6-year experience was 38 % (5 out of 13). Of note, the mortality rate was significantly lower in the latter 3 years of the study period when the procedure was adopted as a primary palliation for HLHS (14 % or 1 out of 7) compared to the initial 3-year period when it was reserved for higher risk cohorts (67 % or 4 out of 6). Median time to subsequent surgery was 3 months (range 1-4 months). One patient required further ductal stenting on follow-up and developed subsequently airway compression. On median follow-up of 24 months, two patients required pulmonary artery arterioplasty. The hybrid procedure may be used for palliation for a variety of cardiac lesions to avoid high-risk surgery in the neonatal period. This approach may be also an alternative in centers performing lower number of Norwood surgery, which has been associated with higher mortality. PMID:26538212

  20. Cardiac Sarcoidosis.

    PubMed

    Birnie, David; Ha, Andrew C T; Gula, Lorne J; Chakrabarti, Santabhanu; Beanlands, Rob S B; Nery, Pablo

    2015-12-01

    Studies suggest clinically manifest cardiac involvement occurs in 5% of patients with pulmonary/systemic sarcoidosis. The principal manifestations of cardiac sarcoidosis (CS) are conduction abnormalities, ventricular arrhythmias, and heart failure. Data indicate that an 20% to 25% of patients with pulmonary/systemic sarcoidosis have asymptomatic (clinically silent) cardiac involvement. An international guideline for the diagnosis and management of CS recommends that patients be screened for cardiac involvement. Most studies suggest a benign prognosis for patients with clinically silent CS. Immunosuppression therapy is advocated for clinically manifest CS. Device therapy, with implantable cardioverter defibrillators, is recommended for some patients. PMID:26593140

  1. Pulmonary resection combined with cardiac operations.

    PubMed

    Canver, C C; Bhayana, J N; Lajos, T Z; Raza, S T; Lewin, A N; Bergsland, J; Mentzer, R M

    1990-11-01

    Surgical management of patients with concomitant critical cardiac disease and resectable lung lesions is controversial. During a 7-year period (1982 to 1988), 21 patients underwent combined cardiac and pulmonary operations. Patients had cardiac symptoms only; the lung lesions were found on preoperative chest roentgenograms. The pathological diagnosis was established in only 2 of the patients before operation. All underwent concurrent pulmonary resection during cardiac operations requiring extracorporeal circulation. The pulmonary operations included 17 wedge resections and four lobectomies. The final diagnoses in 8 patients with stage I non-small cell lung cancer included epidermoid carcinoma (4), adenocarcinoma (3), and bronchoalveolar carcinoma (1). Postoperatively, 1 patient required a permanent pacemaker and 1 patient died. The actuarial survival at 5 years for all patients who underwent combined procedures was 95%. The 5-year survival for the 8 patients with lung cancer was 88% compared with 100% for those with benign pulmonary pathology (p = 0.172). This experience suggests that combining pulmonary resection with cardiac operations is safe and offers a favorable prognosis to a select group of patients. PMID:2241346

  2. Cardiac or Other Implantable Electronic Devices and Sleep-disordered Breathing Implications for Diagnosis and Therapy

    PubMed Central

    Bitter, Thomas; Gutleben, Klaus-Jrgen; Horstkotte, Dieter; Oldenburg, Olaf

    2014-01-01

    Sleep-disordered breathing (SDB) is of growing interest in cardiology because SDB is a highly prevalent comorbidity in patients with a variety of cardiovascular diseases. The prevalence of SDB is particularly high in patients with cardiac dysrhythmias and/or heart failure. In this setting, many patients now have implantable cardiac devices, such as pacemakers, implantable cardioverter-defibrillators or implanted cardiac resynchronisation therapy devices (CRT). Treatment of SDB using implantable cardiac devices has been studied previously, with atrial pacing and CRT being shown not to bring about satisfactory results in SDB care. The latest generations of these devices have the capacity to determine transthoracic impedance, to detect and quantify breathing efforts and to identify SDB. The capability of implantable cardiac devices to detect SDB is of potential importance for patients with cardiovascular disease, allowing screening for SDB, monitoring of the course of SDB in relation to cardiac status, and documenting of the effects of treatment.

  3. Complex regional pain syndrome type I following pacemaker implantation.

    PubMed

    Kamath, Sangita; Rao, Ballamudi Srinivas

    2015-12-01

    A 70-year-old woman presented with burning pain and swelling over dorsum of right hand and small joints of the fingers, associated with redness, feeling of warmth, and stiffness of the fingers, with inability to bend the fingers since 2 months. The symptoms were progressively increasing in intensity for the past 1 month. There was no history of fever or trauma to the hand. Two months before her symptoms started, she had permanent pacemaker implanted for complete heart block with syncope. She was hypertensive and was on regular medication. Her X-ray of right hand showed decreased bone density (demineralisation), suggestive of osteopenia. A diagnosis of reflex sympathetic dystrophy syndrome or complex regional pain syndrome type I induced by pacemaker insertion was made. She was treated with amitriptyline and steroids, after which her symptoms improved dramatically. PMID:26995412

  4. Initial Experience with the Permanent Implantable Transvenous Pacemaker

    PubMed Central

    Firor, W. B.; Goldman, B. S.

    1967-01-01

    Thirty-three patients with heart block were treated by implantation of a permanent transvenous pacemaker. There were no deaths and few complications even though 25 of these patients were over 70 years of age. Follow-up examinations, including electrocardiograms, were done in all patients. The technique of the operation is discussed and the importance of performing it under fluoroscopic guidance in a proper surgical operating suite is emphasized. This arrangement may require the use of a portable image intensifier. This simple, effective procedure can be performed under local anesthesia and with safety, even in the elderly, frail or debilitated patient. Currently it is the authors' method of choice in the treatment of heart block; thoracotomy is now obsolete unless a synchronous pacemaker is needed or a permanent transvenous pacer cannot be inserted. ImagesFig. 1Fig. 2 PMID:6017700

  5. Overdrive suppression of implanted pacemakers in patients with AV block.

    PubMed Central

    Grendahl, H; Miller, M; Kjekshus, J

    1978-01-01

    Patients being permanently paced for symptomatic AV block were studied by overdrive suppression of the QRS-inhibited pacemaker, in order to observe the underlying heart rhythm. The chest wall stimulation method was used. In complete AV block the escape rhythm recovery time proved highly reproducible on repeated testing on the same day, and in many patients remained so over months or years. Occasionally, a doubling of the escape rhythm recovery time was seen, suggesting initial exit block of the escape focus. Resetting of the escape rhythm usually followed an exponential curve until stabilisation after about 3 minutes. An early escape rhythm with a recovery time of less than 4 seconds was found on every occasion in 21 of 58 patients with complete AV block, and inconstantly in 23 more; in 14 it was never observed. Accidental pacing failure was seen in 15 patients. The overdrive suppression test was helpful in selecting pacemaker dependent patients. PMID:637960

  6. FDA recalls: how do pacemaker manufacturers compare?

    PubMed

    Tyers, G F

    1989-09-01

    To evaluate an apparent perception that there is no difference in reliability among the products of the major cardiac pacing system manufacturers, an extensive review of US Food and Drug Administration regulatory actions was performed. The study period was July 1974 through June 1987. The total number of affected devices was collected for each manufacturer. Available sales data were used to calculate their percentage of recalled products during two time periods. The percentage of potentially high-risk devices (Food and Drug Administration class I and II recalls) was high for one company, moderate for one, and relatively low for the rest. Potential biases in some other sources of reliability information, as well as implications for regulatory policies, are discussed. The data reported establish that there have been past deficiencies in recall management. Although further pacing device recalls are probable, appropriate early regulatory and manufacturer action should help to assure that both the immense cost and patient distress caused by pacer and related product problems in the past can be minimized in the future. PMID:2774725

  7. Self-Organized Pacemakers in a Coupled Reaction-Diffusion-Mechanics System

    NASA Astrophysics Data System (ADS)

    Panfilov, A. V.; Keldermann, R. H.; Nash, M. P.

    2005-12-01

    Using a computational model of a coupled reaction-diffusion-mechanics system, we find that mechanical deformation can induce automatic pacemaking activity. Pacemaking is shown to occur after a single electrical or mechanical stimulus in an otherwise nonoscillatory medium. We study the mechanisms underpinning this effect and conditions for its existence. We show that self-organized pacemakers drift throughout the medium to approach attractors with locations that depend on the size of the medium, and on the location of the initial stimulus.

  8. Haemophilus parainfluenzae bacteremia associated with a pacemaker wire localized by gallium scan

    SciTech Connect

    Rosenbaum, G.S.; Calubiran, O.; Cunha, B.A. )

    1990-05-01

    A young woman with a history of sick sinus syndrome and placement of a permanent pacemaker 6 months before admission had fever and Haemophilus parainfluenzae bacteremia. A gallium scan localized the infection to the site of the pacemaker wire. Echocardiograms were negative for any vegetations. The patient responded to cefotaxime and trimethoprim-sulfamethoxazole therapy. We believe that this is the first case of H. parainfluenzae bacteremia associated with a pacemaker wire and localized by gallium scan.

  9. Intraoperative recordings of monophasic action potentials with chronically implantable pacemaker leads.

    PubMed

    Zrenner, B; Müssig, D; Schreieck, J; Weyerbrock, S; Schneider, M; Schaldach, M; Schömig, A; Schmitt, C

    1998-01-01

    Since the development of fractally coated Iridium electrodes recordings of monophasic action potentials are possible. Intraoperative recordings of MAP from 15 pacemaker implantations were done after positioning the chronically implantable pacemaker leads (Biotronik, Berlin, Germany) in the right ventricle by using five screw-in electrodes and ten anchor electrodes. Intraoperative recordings of MAP are possible with all implanted pacemaker leads. The recordings of typical MAP signals were always accompanied with stable electrode positions and good sensing and pacing characteristics. PMID:9474679

  10. Endovascular extraction techniques for pacemaker and ICD lead extraction

    PubMed Central

    Bracke, F.A.; Meijer, A.; van Gelder, B.

    2001-01-01

    In the last few years, comprehensive endovascular techniques have been developed to extract chronically implanted pacemaker and defibrillator leads. It is important that referring physician have knowledge of the advantages and limitations of the different techniques. In this paper we discuss the techniques and results of the currently used endovascular extraction techniques. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7 PMID:25696690

  11. Permanent pacemaker-associated actinomycetemcomitans endocarditis: A case report.

    PubMed

    Li, Zhenhong; Madeo, Jennifer; Ahmed, Shadab; Vidal, Alex; Makaryus, Amgad; Mejia, Jose; Yasmin, Tabassum

    2013-09-01

    Aggregatibacter actinomycetemcomitans is a Gram-negative bacillus, member of the HACEK group of bacteria, and it is a very rare cause of endocarditis. It is also an extremely rare cause of device-associated infection of the heart. We describe the case of a 25 year-old man who presented with pacemaker-associated endocarditis due to Aggregatibacter actinomycetemcomitans and also discuss the implications and treatment of this organism. PMID:24432293

  12. Permanent pacemaker-associated actinomycetemcomitans endocarditis: A case report

    PubMed Central

    Li, Zhenhong; Madeo, Jennifer; Ahmed, Shadab; Vidal, Alex; Makaryus, Amgad; Mejia, Jose; Yasmin, Tabassum

    2013-01-01

    Aggregatibacter actinomycetemcomitans is a Gram-negative bacillus, member of the HACEK group of bacteria, and it is a very rare cause of endocarditis. It is also an extremely rare cause of device-associated infection of the heart. We describe the case of a 25 year-old man who presented with pacemaker-associated endocarditis due to Aggregatibacter actinomycetemcomitans and also discuss the implications and treatment of this organism. PMID:24432293

  13. Inter-Association Task Force Recommendations on Emergency Preparedness and Management of Sudden Cardiac Arrest in High School and College Athletic Programs: A Consensus Statement

    PubMed Central

    Drezner, Jonathan A; Courson, Ron W; Roberts, William O; Mosesso, Vincent N; Link, Mark S; Maron, Barry J

    2007-01-01

    Objective: To assist high school and college athletic programs prepare for and respond to a sudden cardiac arrest (SCA). This consensus statement summarizes our current understanding of SCA in young athletes, defines the necessary elements for emergency preparedness, and establishes uniform treatment protocols for the management of SCA. Background: Sudden cardiac arrest is the leading cause of death in young athletes. The increasing presence of and timely access to automated external defibrillators (AEDs) at sporting events provides a means of early defibrillation and the potential for effective secondary prevention of sudden cardiac death. An Inter-Association Task Force was sponsored by the National Athletic Trainers' Association to develop consensus recommendations on emergency preparedness and management of SCA in athletes. Recommendations: Comprehensive emergency planning is needed for high school and college athletic programs to ensure an efficient and structured response to SCA. Essential elements of an emergency action plan include establishment of an effective communication system, training of anticipated responders in cardiopulmonary resuscitation and AED use, access to an AED for early defibrillation, acquisition of necessary emergency equipment, coordination and integration of on-site responder and AED programs with the local emergency medical services system, and practice and review of the response plan. Prompt recognition of SCA, early activation of the emergency medical services system, the presence of a trained rescuer to initiate cardiopulmonary resuscitation, and access to early defibrillation are critical in the management of SCA. In any collapsed and unresponsive athlete, SCA should be suspected and an AED applied as soon as possible for rhythm analysis and defibrillation if indicated. PMID:17597956

  14. Physiological effects of light on the human circadian pacemaker

    NASA Technical Reports Server (NTRS)

    Shanahan, T. L.; Czeisler, C. A.

    2000-01-01

    The physiology of the human circadian pacemaker and its influence and on the daily organization of sleep, endocrine and behavioral processes is an emerging interest in science and medicine. Understanding the development, organization and fundamental properties underlying the circadian timing system may provide insight for the application of circadian principles to the practice of clinical medicine, both diagnostically (interpretation of certain clinical tests are dependent on time of day) and therapeutically (certain pharmacological responses vary with the time of day). The light-dark cycle is the most powerful external influence acting upon the human circadian pacemaker. It has been shown that timed exposure to light can both synchronize and reset the phase of the circadian pacemaker in a predictable manner. The emergence of detectable circadian rhythmicity in the neonatal period is under investigation (as described elsewhere in this issue). Therefore, the pattern of light exposure provided in the neonatal intensive care setting has implications. One recent study identified differences in both amount of sleep time and weight gain in infants maintained in a neonatal intensive care environment that controlled the light-dark cycle. Unfortunately, neither circadian phase nor the time of day has been considered in most clinical investigations. Further studies with knowledge of principles characterizing the human circadian timing system, which governs a wide array of physiological processes, are required to integrate these findings with the practice of clinical medicine.

  15. High-intensity cardiac rehabilitation training of a commercial pilot who, after percutaneous coronary intervention, wanted to continue participating in a rigorous strength and conditioning program.

    PubMed

    Shrestha, Sanjay; Adams, Jenny; Lawrence, Anne; Schussler, Jeffrey M

    2016-01-01

    After undergoing elective percutaneous coronary intervention, a 64-year-old commercial pilot was referred to cardiac rehabilitation. His stated goals were to continue participating in a rigorous strength and conditioning program at a community workout facility and to resume working as a pilot. To help him meet those goals, we designed and implemented a regimen of high-intensity exercises, with quick transitions between a variety of tasks that are not typically included in cardiac rehabilitation programs (e.g., medicine ball throws, push-ups, dead lifts, squats, military presses, sprints, and lunges). The training was symptom limited, enabling the patient to reach extreme levels of physical exertion in a controlled, monitored setting. By studying his training data (heart rate, blood pressure, and rating of perceived exertion), we were able to give him specific recommendations for controlling his exercise intensity after graduating from our program. More than 18 months later, he continues to exercise vigorously 3 days per week and is working as a commercial pilot. PMID:26722183

  16. High-intensity cardiac rehabilitation training of a commercial pilot who, after percutaneous coronary intervention, wanted to continue participating in a rigorous strength and conditioning program

    PubMed Central

    Shrestha, Sanjay; Lawrence, Anne; Schussler, Jeffrey M.

    2016-01-01

    After undergoing elective percutaneous coronary intervention, a 64-year-old commercial pilot was referred to cardiac rehabilitation. His stated goals were to continue participating in a rigorous strength and conditioning program at a community workout facility and to resume working as a pilot. To help him meet those goals, we designed and implemented a regimen of high-intensity exercises, with quick transitions between a variety of tasks that are not typically included in cardiac rehabilitation programs (e.g., medicine ball throws, push-ups, dead lifts, squats, military presses, sprints, and lunges). The training was symptom limited, enabling the patient to reach extreme levels of physical exertion in a controlled, monitored setting. By studying his training data (heart rate, blood pressure, and rating of perceived exertion), we were able to give him specific recommendations for controlling his exercise intensity after graduating from our program. More than 18 months later, he continues to exercise vigorously 3 days per week and is working as a commercial pilot. PMID:26722183

  17. Self-organized pacemakers and bistability of pulses in an excitable medium

    NASA Astrophysics Data System (ADS)

    Stich, Michael; Mikhailov, Alexander S.; Kuramoto, Yoshiki

    2009-02-01

    Pattern formation in an excitable medium described by a three-component reaction-diffusion system is investigated. Our focus is on stable self-organized pacemakers which give rise to spatially extended target patterns. Bistability of pulse solutions in the excitable regime is also reported, and interactions of the different pulses with each other and the pacemaker are studied. Self-organized pacemakers are created by a suitable perturbation from the steady state or through interaction of pulses. Bound states of one-dimensional pacemakers and phase flips are also observed.

  18. Powering pacemakers from heartbeat vibrations using linear and nonlinear energy harvesters

    NASA Astrophysics Data System (ADS)

    Amin Karami, M.; Inman, Daniel J.

    2012-01-01

    Linear and nonlinear piezoelectric devices are introduced to continuously recharge the batteries of the pacemakers by converting the vibrations from the heartbeats to electrical energy. The power requirement of a pacemaker is very low. However, after few years, patients require another surgical operation just to replace their pacemaker battery. Linear low frequency and nonlinear mono-stable and bi-stable energy harvesters are designed according to the especial signature of heart vibrations. The proposed energy harvesters are robust to variation of heart rate and can meet the power requirement of pacemakers.

  19. Beyond Bowditch: the convergence of cardiac chronotropy and inotropy.

    PubMed

    Lakatta, Edward G

    2004-06-01

    The ability of the heart to acutely beat faster and stronger is central to the vertebrate survival instinct. Released neurotransmitters, norepinephrine and epinephrine, bind to beta-adrenergic receptors (beta-AR) on pacemaker cells comprising the sinoatrial node, and to beta-AR on ventricular myocytes to modulate cellular mechanisms that govern the frequency and amplitude, respectively, of the duty cycles of these cells. While a role for sarcoplasmic reticulum Ca(2+) cycling via SERCA2 and ryanodine receptors (RyR) has long been appreciated with respect to cardiac inotropy, recent evidence also implicates Ca(2+) cycling with respect to chronotropy. In spontaneously beating primary sinoatrial nodal pacemaker cells, RyR Ca(2+) releases occurring during diastolic depolarization activate the Na(+)-Ca(2+) exchanger (NCX) to produce an inward current that enhances their diastolic depolarization rate, and thus increases their beating rate. beta-AR stimulation synchronizes RyR activation and Ca(2+) release to effect an increased beating rate in pacemaker cells and contraction amplitude in myocytes: in pacemaker cells, the beta-AR stimulation synchronization of RyR activation occurs during the diastolic depolarization, and augments the NCX inward current; in ventricular myocytes, beta-AR stimulation synchronizes the openings of unitary L-type Ca(2+) channel activation following the action potential, and also synchronizes RyR Ca(2+) releases following depolarization, and in the absence of depolarization, both leading to the generation of a global cytosolic Ca(i) transient of increased amplitude and accelerated kinetics. Thus, beta-AR stimulation induced synchronization of RyR activation (recruitment of additional RyRs to fire) and of the ensuing Ca(2+) release cause the heart to beat both stronger and faster, and is thus, a common mechanism that links both the maximum achievable cardiac inotropy and chronotropy. PMID:15110153

  20. A Comparative Survey of Pacemaker Implantation in Trinidad and Tobago in 2005 and 2009

    PubMed Central

    Henry, R; Dookie, T; Primus, E

    2014-01-01

    ABSTRACT Objective: The indications for permanent pacemaker implantations in Trinidad have expanded from initially symptomatic bradycardia to now include complex devices. A retrospective review of the available data was conducted to better understand the evolving trends in device implantation in Trinidad and Tobago. Methods: Data were collated from the two major implanting teams in Trinidad for the years 2005 and 2009. The two implanting centres were the Advanced Cardiovascular Institute (ACI) at Westshore Medical Centre and the Catheterization Laboratory of the Eric Williams Medical Sciences Complex (EWMSC). Data were based on retrospective collation using the implantation records. Results: The implantation rate for new devices increased from 39 per million to 103 per million population. The most common indications for new device implants in 2009 were high degree atrioventricular (AV) block (53%) and sick sinus syndrome (22%), with the notable appearance of congestive cardiomyopathy (13%) which was not present in the earlier cohort. Of particular note, 23 high-end devices were implanted in 2009. These were five cardiac-resynchronization therapy (CRT-P) devices, 14 automatic implantable cardio-defibrillator (AICD) devices and four combined cardiac-resynchronization therapy with defibrillator (CRT-D) devices versus none in 2005. Conclusions: In summary, over the period 2005 to 2009, a substantial increase in device implantation rates has occurred which now include high-end complex devices. Absolute rates, however, remain far below that of developed countries, indicating that the true need remains underserved. Furthermore, adjustment for gross domestic product suggests that the relatively buoyant economy of Trinidad and Tobago is capable of servicing a greater proportion of this need than is currently met. PMID:26108119

  1. Pacemaker Primary Curriculum; Lesson Book Level D.

    ERIC Educational Resources Information Center

    Ross, Dorothea M.; Ross, Sheila A.

    This lesson book, which is the last in a four-level program for young children with learning difficulties, describes the purpose of and equipment and procedures for teaching lessons in the following subject areas on the primary level: arithmetic, reading, vocabulary, spelling, printing, listening, planning and problem solving, social behavior,

  2. Pacemaker Primary Curriculum; Lesson Book Level A.

    ERIC Educational Resources Information Center

    Ross, Dorothea M.; Ross, Sheila A.

    This lesson book, which is the first in a four-level program for young children with learning difficulties, describes the purpose of and equipment and procedures for teaching lessons in the following subject areas on the kindergarten level: arithmetic concepts, number concepts, reading readiness, vocabulary, language, listening, social behavior,

  3. Pacemaker Primary Curriculum; Lesson Book Level C.

    ERIC Educational Resources Information Center

    Ross, Dorothea M.; Ross, Sheila A.

    This lesson book, which is the third in a four-level program for young children with learning difficulties, describes the purpose of and equipment and procedures for teaching lessons in the following subject areas on the primary grade level: arithmetic, reading, vocabulary, spelling, printing, listening, planning, problem solving, social behavior,

  4. Pacemaker Primary Curriculum; Lesson Book Level B.

    ERIC Educational Resources Information Center

    Ross, Dorothea M.; Ross, Sheila A.

    This lesson book, which is the second in a four-level program for young children with learning difficulties, describes the purpose of and equipment and procedures for teaching lessons in the following subjects areas on the primary grade level: arithmetic, reading, vocabulary, listening, planning, problem solving, social behavior, art, music, and

  5. High thresholds may alter end-of-life behavior in a dual chamber pacemaker.

    PubMed

    Kraus, M; Buckingham, T A; Candinas, R

    1997-06-01

    We noted a series of 12 consecutive patients with a DDD Genisis pacemaker that showed an unexpected and a relatively rapid fall in battery voltage and output as these devices approached end-of-life (EOL). Twenty-one of 24 leads were Vitatron Helifix leads and there was a relatively high mean threshold (atrial 2.5 +/- 0.94 V; ventricular 2.9 +/- 0.65 V). These devices were replaced after 65 +/- 12 months. During the 9.3 +/- 3.5 months before replacement, a striking fall in voltage from 2.7 +/- 0.04 V to 2.49 +/- 0.05 V was seen. Battery impedance rose from 3 +/- 1.2 K omega to 10.2 +/- 4.3 K omega during this same period. We unexpectedly observed a marked difference between programmed and telemetered output for both atrial (50%) and ventricular leads (30%). A discrepancy between measured and telemetered magnet rate was also seen. Despite this relatively rapid fall in battery voltage, several of these devices did not meet the manufacturer's recommended replacement time (RRT) criteria by magnet rate or according to the projected RRT determined by the relationship of battery impedance to current drain. These data have implications for the selection of RRT and EOL criteria for this device. Magnet rate measured by surface ECG was the safest indicator for RRT. Follow-up for this pulse generator should be increased to every 2 months when battery impedance is > 2 KOhms or if there is a difference between programmed and measured output amplitude of more than 15%. The data also highlight the effect of combining high threshold leads with modern pacemakers with relatively "small" batteries as well as certain problems with telemetered data. PMID:9227769

  6. Cardiac Applications for Human Pluripotent Stem Cells

    PubMed Central

    Shiba, Yuji; Hauch, Kip D.; Laflamme, Michael A.

    2010-01-01

    Human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) can self-renew indefinitely, while maintaining the capacity to differentiate into useful somatic cell types, including cardiomyocytes. As such, these stem cell types represent an essentially inexhaustible source of committed human cardiomyocytes of potential use in cell-based cardiac therapies, high-throughput screening and safety testing of new drugs, and modeling human heart development. These stem cell-derived cardiomyocytes have an unambiguous cardiac phenotype and proliferate robustly both in vitro and in vivo. Recent transplantation studies in preclinical models have provided exciting proof-of-principle for their use in infarct repair and in the formation of a biological pacemaker. While these successes give reason for cautious optimism, major challenges remain to the successful application of hESCs (or hiPSCs) to cardiac repair, including the need for preparations of high cardiac purity, improved methods of delivery, and approaches to overcome immune rejection and other causes of graft cell death. In this review, we describe the phenotype of hESC- and hiPSC-derived cardiomyocytes, the state of preclinical transplantation studies with these cells, and potential approaches to overcome the aforementioned hurdles. PMID:19689350

  7. Cardiac Catheterization

    MedlinePLUS

    ... done during a cardiac catheterization include: closing small holes inside the heart repairing leaky or narrow heart ... bandage. It's normal for the site to be black and blue, red, or slightly swollen for a ...

  8. Cardiac Catheterization

    MedlinePLUS

    ... where the catheter was inserted. Cardiac catheterization rarely causes serious complications. Rate This Content: NEXT >> Updated: January 30, 2012 Twitter Facebook YouTube Google+ SITE INDEX ACCESSIBILITY PRIVACY STATEMENT FOIA ...

  9. Cardiac tamponade

    MedlinePLUS

    ... blood. Cardiac tamponade can occur due to: Dissecting aortic aneurysm (thoracic) End-stage lung cancer Heart attack ( acute ... is felt in the neck, shoulder, back, or abdomen Chest pain that gets worse with deep breathing ...

  10. Cardiac amyloidosis

    MedlinePLUS

    ... body. Medicines including digoxin, calcium channel blockers, and beta blockers may be used in people with atrial fibrillation. However, the drugs must be used with caution, and the dosage must be carefully monitored. People with cardiac amyloidosis ...

  11. Cause and Long-Term Outcome of Cardiac Tamponade.

    PubMed

    Snchez-Enrique, Cristina; Nuez-Gil, Ivn J; Viana-Tejedor, Ana; De Agustn, Alberto; Vivas, David; Palacios-Rubio, Julin; Vilchez, Jean Paul; Cecconi, Alberto; Macaya, Carlos; Fernndez-Ortiz, Antonio

    2016-02-15

    Cardiac tamponade is a life-threatening condition, whose current specific cause and outcome are unknown. Our purpose was to analyze it. We performed a retrospective observational study with prospective follow-up data including 136 consecutive patients admitted with diagnosis of cardiac tamponade, from 2003 to 2013. We thoroughly recorded variables as clinical features, drainage/pericardiocentesis, fluid characteristics, and long-term events (new cardiac tamponade death). The median age was 65 17years (55% men). In the baseline characteristics, 70% were no smokers, 12% were on anticoagulation, and 13 had suffered a previous myocardial infarction. In the preceding month, 15 patients had undergone a cardiac catheterization, 5 cardiac surgery, and 5 pacemaker insertion. Fever was observed in 16% of patients and 21% displayed other inflammatory symptoms. In 81% of patients, pericardiocentesis was needed. The fluid was hemorrhagic or a transudate in the majority, with positive cytology in 15% and bacteria in 3.7%. Main causes were malignancy (32%), infection (24%), idiopathic (16%), iatrogenic (15%), postmyocardial infarction (7%), uremic (4%), and other causes (2%). After a maximum follow-up of 10.4years, cardiac tamponade recurred in 10% of the cases (62% in the neoplastic group) and the 48% of patients died (89% in the neoplastic cohort). In conclusion, most cardiac tamponades are due to malignancy, having this specific cause a poorer outcome, probably as a manifestation of an advanced disease. The rest of causes, after an aggressive intensive management, have a good prognosis, especially the iatrogenic. PMID:26718232

  12. Circadian Activators Are Expressed Days before They Initiate Clock Function in Late Pacemaker Neurons from Drosophila.

    PubMed

    Liu, Tianxin; Mahesh, Guruswamy; Houl, Jerry H; Hardin, Paul E

    2015-06-01

    Circadian pacemaker neurons in the Drosophila brain control daily rhythms in locomotor activity. These pacemaker neurons can be subdivided into early or late groups depending on whether rhythms in period (per) and timeless (tim) expression are initiated at the first instar (L1) larval stage or during metamorphosis, respectively. Because CLOCK-CYCLE (CLK-CYC) heterodimers initiate circadian oscillator function by activating per and tim transcription, a Clk-GFP transgene was used to mark when late pacemaker neurons begin to develop. We were surprised to see that CLK-GFP was already expressed in four of five clusters of late pacemaker neurons during the third instar (L3) larval stage. CLK-GFP is only detected in postmitotic neurons from L3 larvae, suggesting that these four late pacemaker neuron clusters are formed before the L3 larval stage. A GFP-cyc transgene was used to show that CYC, like CLK, is also expressed exclusively in pacemaker neurons from L3 larval brains, demonstrating that CLK-CYC is not sufficient to activate per and tim in late pacemaker neurons at the L3 larval stage. These results suggest that most late pacemaker neurons develop days before novel factors activate circadian oscillator function during metamorphosis. PMID:26041931

  13. What Is Cardiac Rehabilitation?

    MedlinePLUS

    ... such as coronary artery disease (CAD), angina or heart failure. • H eart procedures or surgeries, including coronary artery bypass graft (CABG) surgery, angioplasty, stenting, valve replacement, a pacemaker or implantable cardioverter defibrillator (ICD). What ...

  14. Evaluation of the Genetic Basis of Familial Aggregation of Pacemaker Implantation by a Large Next Generation Sequencing Panel

    PubMed Central

    Steiner, Hillel A.; Uradu, Andrea; Lynnes, Ty C.; Groh, William J.; Miller, John M.; Lin, Hai; Gao, Hongyu; Wang, Zhiping; Liu, Yunlong; Chen, Peng-Sheng; Vatta, Matteo

    2015-01-01

    Background The etiology of conduction disturbances necessitating permanent pacemaker (PPM) implantation is often unknown, although familial aggregation of PPM (faPPM) suggests a possible genetic basis. We developed a pan-cardiovascular next generation sequencing (NGS) panel to genetically characterize a selected cohort of faPPM. Materials and Methods We designed and validated a custom NGS panel targeting the coding and splicing regions of 246 genes with involvement in cardiac pathogenicity. We enrolled 112 PPM patients and selected nine (8%) with faPPM to be analyzed by NGS. Results Our NGS panel covers 95% of the intended target with an average of 229x read depth at a minimum of 15-fold depth, reaching a SNP true positive rate of 98%. The faPPM patients presented with isolated cardiac conduction disease (ICCD) or sick sinus syndrome (SSS) without overt structural heart disease or identifiable secondary etiology. Three patients (33.3%) had heterozygous deleterious variants previously reported in autosomal dominant cardiac diseases including CCD: LDB3 (p.D117N) and TRPM4 (p.G844D) variants in patient 4; TRPM4 (p.G844D) and ABCC9 (p.V734I) variants in patient 6; and SCN5A (p.T220I) and APOB (p.R3527Q) variants in patient 7. Conclusion FaPPM occurred in 8% of our PPM clinic population. The employment of massive parallel sequencing for a large selected panel of cardiovascular genes identified a high percentage (33.3%) of the faPPM patients with deleterious variants previously reported in autosomal dominant cardiac diseases, suggesting that genetic variants may play a role in faPPM. PMID:26636822

  15. Development of the Mouse Circadian Pacemaker: Independence from Environmental Cycles*

    PubMed Central

    Davis, Fred C.; Menaker, Michael

    2013-01-01

    Summary The freerunning period (?) of the circadian pacemaker underlying the wheel-running activity rhythm of Mus musculus was found to be unaffected by the periods of environmental cycles (maternal and light/dark) under which the mice are raised. Mice born to mothers entrained to periods (T) of 28 or 20 h (ratio of light to dark of 14/10) and maintained on those cycle until beyond puberty showed only a temporary difference in freerunning period when placed into constant darkness. Such temporary after-effects of entrainment were shown, as had been previously, to occur in animals exposed to non-24-h cycles as adults only.After-effects on the ratio of activity to rest (?/?) were not even temporarily different in animals raised on T = 28 or T = 20.Rearing on T = 28 or T = 20 did not affect the abilities of animals to entrain to these cycles later in life.Measurements from young and old animals as well as remeasurement of the young animals later in their lives revealed several effects of age on the pacemaker: a) After-effects on freerunning period after T = 28 or T = 20 are not greater but last longer in older animals; b) Freerunning period is shorter in younger animals; and c) The ratio of activity to rest changes over time in constant darkness and is greater in young animals. Together these suggest that pacemaker plasticity reflected in changes in ? and ?/? over time in constant darkness decreases with age.The length of gestation measured in real time was the same in mice entrained to T = 28 or T = 20, demonstrating that gestation is not measured in circadian cycles. PMID:25309022

  16. Development of the Mouse Circadian Pacemaker: Independence from Environmental Cycles.

    PubMed

    Davis, Fred C; Menaker, Michael

    1981-12-01

    The freerunning period (?) of the circadian pacemaker underlying the wheel-running activity rhythm of Mus musculus was found to be unaffected by the periods of environmental cycles (maternal and light/dark) under which the mice are raised. Mice born to mothers entrained to periods (T) of 28 or 20 h (ratio of light to dark of 14/10) and maintained on those cycle until beyond puberty showed only a temporary difference in freerunning period when placed into constant darkness. Such temporary 'after-effects ' of entrainment were shown, as had been previously, to occur in animals exposed to non-24-h cycles as adults only.After-effects on the ratio of activity to rest (?/?) were not even temporarily different in animals raised on T = 28 or T = 20.Rearing on T = 28 or T = 20 did not affect the abilities of animals to entrain to these cycles later in life.Measurements from young and old animals as well as remeasurement of the young animals later in their lives revealed several effects of age on the pacemaker: a) After-effects on freerunning period after T = 28 or T = 20 are not greater but last longer in older animals; b) Freerunning period is shorter in younger animals; and c) The ratio of activity to rest changes over time in constant darkness and is greater in young animals. Together these suggest that pacemaker 'plasticity' reflected in changes in ? and ?/? over time in constant darkness decreases with age.The length of gestation measured in 'real' time was the same in mice entrained to T = 28 or T = 20, demonstrating that gestation is not measured in circadian cycles. PMID:25309022

  17. Linear and nonlinear energy harvesters for powering pacemakers from heart beat vibrations

    NASA Astrophysics Data System (ADS)

    Karami, M. Amin; Inman, Daniel J.

    2011-03-01

    Linear and nonlinear piezoelectric devices are introduced to continuously recharge the batteries of the pacemakers by converting the vibrations from the heartbeats to electrical energy. The power requirement of the pacemakers is very low. At the same time, after about 10 years from the original implantation of the pacemakers, patients have to go through another surgical operation just to replace the batteries of their pacemakers. We investigate using vibration energy harvesters to significantly increase the battery life of the pace makers. The major source of vibrations in chest area is due to heartbeats. Linear low frequency and nonlinear mono-stable and bi-stable energy harvesters are designed according to especial signature of heart vibrations. The proposed energy harvesters are robust to variations of heart beat frequency and can meet the power requirement of the pacemakers.

  18. Synchronous Drosophila circadian pacemakers display nonsynchronous Ca²⁺ rhythms in vivo.

    PubMed

    Liang, Xitong; Holy, Timothy E; Taghert, Paul H

    2016-02-26

    In Drosophila, molecular clocks control circadian rhythmic behavior through a network of ~150 pacemaker neurons. To explain how the network's neuronal properties encode time, we performed brainwide calcium imaging of groups of pacemaker neurons in vivo for 24 hours. Pacemakers exhibited daily rhythmic changes in intracellular Ca(2+) that were entrained by environmental cues and timed by molecular clocks. However, these rhythms were not synchronous, as each group exhibited its own phase of activation. Ca(2+) rhythms displayed by pacemaker groups that were associated with the morning or evening locomotor activities occurred ~4 hours before their respective behaviors. Loss of the receptor for the neuropeptide PDF promoted synchrony of Ca(2+) waves. Thus, neuropeptide modulation is required to sequentially time outputs from a network of synchronous molecular pacemakers. PMID:26917772

  19. Injury to the coronary arteries and related structures by implantation of cardiac implantable electronic devices.

    PubMed

    Pang, Benjamin J; Barold, S Serge; Mond, Harry G

    2015-04-01

    Damage to the coronary arteries and related structures from pacemaker and implantable cardioverter-defibrillator lead implantation is a rarely reported complication that can lead to myocardial infarction and pericardial tamponade that may occur acutely or even years later. We summarize the reported cases of injury to coronary arteries and related structures and review the causes of troponin elevation in the setting of cardiac implantable electronic device implantation. PMID:25564549

  20. Right atrial pacemaker lead thrombosis causing tricuspid inflow obstruction.

    PubMed

    Tugcu, Aylin; Yildirimturk, Ozlem; Tayyareci, Yelda; Sagbas, Ertan; Yazicioglu, Nuran; Aytekin, Saide

    2009-02-01

    A 75-year-old man was admitted to our hospital with a complaint of progressive dyspnea with effort. The patient had a permanent pacemaker that was implanted 16 years ago. Transesophageal echocardiography revealed a large, mobile mass in the right atrium attaching to the insertion site of the atrial lead at the tricuspid valve level. Because of the size, mobility, and location of the mass, urgent surgical removal was considered. The mass was successfully removed. Histologic examination of the mass demonstrated a partially organized thrombus. The postoperative course was uneventful and the patient's symptoms improved remarkably after operation. PMID:19170918

  1. A novel curve fitting method for AV optimisation of biventricular pacemakers.

    PubMed

    Dehbi, Hakim-Moulay; Jones, Siana; Sohaib, S M Afzal; Finegold, Judith A; Siggers, Jennifer H; Stegemann, Berthold; Whinnett, Zachary I; Francis, Darrel P

    2015-09-01

    In this study, we designed and tested a new algorithm, which we call the 'restricted parabola', to identify the optimum atrioventricular (AV) delay in patients with biventricular pacemakers. This algorithm automatically restricts the hemodynamic data used for curve fitting to the parabolic zone in order to avoid inadvertently selecting an AV optimum that is too long.We used R, a programming language and software environment for statistical computing, to create an algorithm which applies multiple different cut-offs to partition curve fitting of a dataset into a parabolic and a plateau region and then selects the best cut-off using a least squares method. In 82 patients, AV delay was adjusted and beat-to-beat systolic blood pressure (SBP) was measured non-invasively using our multiple-repetition protocol. The novel algorithm was compared to fitting a parabola across the whole dataset to identify how many patients had a plateau region, and whether a higher hemodynamic response was achieved with one method.In 9/82 patients, the restricted parabola algorithm detected that the pattern was not parabolic at longer AV delays. For these patients, the optimal AV delay predicted by the restricted parabola algorithm increased SBP by 1.36?mmHg above that predicted by the conventional parabolic algorithm (95% confidence interval: 0.65 to 2.07?mmHg, p-value = 0.002).AV optima selected using our novel restricted parabola algorithm give a greater improvement in acute hemodynamics than fitting a parabola across all tested AV delays. Such an algorithm may assist the development of automated methods for biventricular pacemaker optimisation. PMID:26246270

  2. The Different Effects of BMI and WC on Organ Damage in Patients from a Cardiac Rehabilitation Program after Acute Coronary Syndrome

    PubMed Central

    Xu, Lin; Zhao, Hui; Qiu, Jian; Zhu, Wei; Lei, Hongqiang; Cai, Zekun; Lin, Wan-Hua; Huang, Wenhua; Zhang, Heye; Zhang, Yuan-Ting

    2015-01-01

    One of the purposes of cardiac rehabilitation (CR) after acute coronary syndrome (ACS) is to monitor and control weight of the patient. Our study is to compare the different obesity indexes, body mass index (BMI), and waist circumference (WC), through one well-designed CR program (CRP) with ACS in Guangzhou city of Guangdong Province, China, in order to identify different effects of BMI and WC on organ damage. In our work, sixty-one patients between October 2013 and January 2014 fulfilled our study. We collected the vital signs by medical records, the clinical variables of body-metabolic status by fasting blood test, and the organ damage variables by submaximal exercise treadmill test (ETT) and ultrasonic cardiogram (UCG) both on our inpatient and four-to-five weeks of outpatient part of CRP after ACS. We mainly used two-tailed Pearson's test and liner regression to evaluate the relationship of BMI/WC and organ damage. Our results confirmed that WC could be more accurate than BMI to evaluate the cardiac function through the changes of left ventricular structure on the CRP after ACS cases. It makes sense of early diagnosis, valid evaluation, and proper adjustment to ACS in CRP of the obesity individuals in the future. PMID:26247035

  3. Late-presenting complete heart block after pediatric cardiac surgery.

    PubMed

    Nasser, Bana Agha; Mesned, Abdu Rahman; Mohamad, Tagelden; Kabbani, Mohamad S

    2016-01-01

    Late presenting complete heart block after pediatric cardiac surgery is a rare complication and its management is well defined once the initial diagnosis in made timely and appropriately. In this report we described a child who underwent atrioventricular septal defect repair with a normal sinus rhythm during the postoperative period, as well as during the first 2 years of follow up. She subsequently developed complete heart block with bradycardia that required insertion of a pacemaker. Here we discuss this unusual late-presenting complication, possible risk factors, and management. PMID:26778907

  4. Theoretical model for solid-state lithium-halide cells for cardiac pacemakers

    SciTech Connect

    Hermann, A.M.; Luksha, E.

    1980-01-01

    A theoretical model for electrochemical cells formed with lithium anodes and halogen/charge-transfer-complex (CTC) cathodes is proposed. The electrolyte, the corresponding lithium halide, is initially formed in situ, and is added as a product of the electrochemical reaction. Current limitation due to lithium self-diffusion in the anode is considered. Calculations for the internal resistance of these cells are given for bromine-CTC cathodes assuming a crystalline solid-layer LiBr electrolyte. Calculations for self-discharge due to atomic bromine diffusion through the electrolyte to the anode are also presented. The actual state of the LiBr electrolyte is explained with recent scanning electron micrographs. Predictions of the theoretical model are compared to discharge data and to recent microcalorimetric self-discharge measurements. 15 refs.

  5. Mechanisms that match ATP supply to demand in cardiac pacemaker cells during high ATP demand

    PubMed Central

    Yaniv, Yael; Spurgeon, Harold A.; Ziman, Bruce D.; Lyashkov, Alexey E.

    2013-01-01

    The spontaneous action potential (AP) firing rate of sinoatrial node cells (SANCs) involves high-throughput signaling via Ca2+-calmodulin activated adenylyl cyclases (AC), cAMP-mediated protein kinase A (PKA), and Ca2+/calmodulin-dependent protein kinase II (CaMKII)-dependent phosphorylation of SR Ca2+ cycling and surface membrane ion channel proteins. When the throughput of this signaling increases, e.g., in response to ?-adrenergic receptor activation, the resultant increase in spontaneous AP firing rate increases the demand for ATP. We hypothesized that an increase of ATP production to match the increased ATP demand is achieved via a direct effect of increased mitochondrial Ca2+ (Ca2+m) and an indirect effect via enhanced Ca2+-cAMP/PKA-CaMKII signaling to mitochondria. To increase ATP demand, single isolated rabbit SANCs were superfused by physiological saline at 35 0.5C with isoproterenol, or by phosphodiesterase or protein phosphatase inhibition. We measured cytosolic and mitochondrial Ca2+ and flavoprotein fluorescence in single SANC, and we measured cAMP, ATP, and O2 consumption in SANC suspensions. Although the increase in spontaneous AP firing rate was accompanied by an increase in O2 consumption, the ATP level and flavoprotein fluorescence remained constant, indicating that ATP production had increased. Both Ca2+m and cAMP increased concurrently with the increase in AP firing rate. When Ca2+m was reduced by Ru360, the increase in spontaneous AP firing rate in response to isoproterenol was reduced by 25%. Thus, both an increase in Ca2+m and an increase in Ca2+ activated cAMP-PKA-CaMKII signaling regulate the increase in ATP supply to meet ATP demand above the basal level. PMID:23604710

  6. Mechanisms that match ATP supply to demand in cardiac pacemaker cells during high ATP demand.

    PubMed

    Yaniv, Yael; Spurgeon, Harold A; Ziman, Bruce D; Lyashkov, Alexey E; Lakatta, Edward G

    2013-06-01

    The spontaneous action potential (AP) firing rate of sinoatrial node cells (SANCs) involves high-throughput signaling via Ca(2+)-calmodulin activated adenylyl cyclases (AC), cAMP-mediated protein kinase A (PKA), and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII)-dependent phosphorylation of SR Ca(2+) cycling and surface membrane ion channel proteins. When the throughput of this signaling increases, e.g., in response to ?-adrenergic receptor activation, the resultant increase in spontaneous AP firing rate increases the demand for ATP. We hypothesized that an increase of ATP production to match the increased ATP demand is achieved via a direct effect of increased mitochondrial Ca(2+) (Ca(2+)m) and an indirect effect via enhanced Ca(2+)-cAMP/PKA-CaMKII signaling to mitochondria. To increase ATP demand, single isolated rabbit SANCs were superfused by physiological saline at 35 0.5C with isoproterenol, or by phosphodiesterase or protein phosphatase inhibition. We measured cytosolic and mitochondrial Ca(2+) and flavoprotein fluorescence in single SANC, and we measured cAMP, ATP, and O? consumption in SANC suspensions. Although the increase in spontaneous AP firing rate was accompanied by an increase in O? consumption, the ATP level and flavoprotein fluorescence remained constant, indicating that ATP production had increased. Both Ca(2+)m and cAMP increased concurrently with the increase in AP firing rate. When Ca(2+)m was reduced by Ru360, the increase in spontaneous AP firing rate in response to isoproterenol was reduced by 25%. Thus, both an increase in Ca(2+)m and an increase in Ca(2+) activated cAMP-PKA-CaMKII signaling regulate the increase in ATP supply to meet ATP demand above the basal level. PMID:23604710

  7. X-ray effects on pacemaker type circuits

    SciTech Connect

    Blamires, N.G.; Myatt, J.

    1982-03-01

    Queries have been raised concerning the potential hazards of X-ray irradiation on patients using the new generation of heart pacemakers based on digital circuitry. The present study was undertaken to provide some answers to these queries. The work was conducted in two parts. First, a literature search was done and, second, circuits using current state of the art digital technology were irradiated with X-rays. Watch circuits were chosen because of their availability and built-in facilities by which their function could be tested. Doses up to 330 rads were administered to them using energies of 46, 114, and 141 KeV. The conclusion drawn from both parts of the study was that X-rays used for diagnostic purposes were unlikely to affect the performance of this type of circuit in any way. It was accepted that for therapeutic purposes doses far in excess of this are administered and circuit malfunctions are likely to occur. To assess the probability of a digital pacemaker malfunctioning, samples of that particular type would have to be irradiated at the relevant dose.

  8. Pacemaker dynamics in the full Morris-Lecar model

    NASA Astrophysics Data System (ADS)

    Gonzlez-Miranda, J. M.

    2014-09-01

    This article reports the finding of pacemaker dynamics in certain region of the parameter space of the three-dimensional version of the Morris-Lecar model for the voltage oscillations of a muscle cell. This means that the cell membrane potential displays sustained oscillations in the absence of an external electrical stimulation. The development of this dynamic behavior is shown to be tied to the strength of the leak current contained in the model. The approach followed is mostly based on the use of linear stability analysis and numerical continuation techniques. In this way it is shown that the oscillatory dynamics is associated to the existence of two Hopf bifurcations, one subcritical and other supercritical. Moreover, it is explained that in the region of parameter values most commonly studied for this model such pacemaker dynamics is not displayed because of the development of two fold bifurcations, with the increase of the strength of the leak current, whose interaction with the Hopf bifurcations destroys the oscillatory dynamics.

  9. DsRNA as a stimulator of cell pacemaker activity

    SciTech Connect

    Airapetyan, S.N.; Zakharyan, R.A.; Rychkov, G.E.; Dadalyan, S.S.; Bakunts, I.S.; Agabalyan, A.S.

    1986-03-01

    The authors study the action of double-stranded RNAs (dsRNA) on the characteristics of neuron pacemaker activity which permits prediction of the character of action of dsRNA on the pacemaker activity of cells and organs, and takes the investigators closer to an understanding of the membrane mechanisms underlying the action of dsRNA on the cell. The methods for isolating and fractionating dsRNA from yeasts and the intracellular recording of the electrical activity of the snail giant neuron have been described by the authors earlier. The authors determined the dependence of Ca/sup 2 +/ entry upon dsRNA concentration using the isotope /sup 45/Ca. Preweighed ganglia were incubated five each for an hour in 2 ml Ringer's solution containing dsRNA and 5 microliters /sup 45/CaCl/sub 2/ of 12.5 mCi activity. After incubation, the ganglia were rinsed three times for 8 min each time in normal Ringers solution. The washed ganglia were dissolved for one day in KOH. The amount of isotope entering was counted using Brav's scintillator and an RGT counter tuned to the /sup 45/Ca isotope. The physiological saline used for the isolated ganglion contained 85 mmole NaCl, 4 mmole KCl, 8 mmole CaCl/sub 2/, 10 mmole MgCl/sub 2/, 10 mmole Tris-HCl, and 5 mmole glucose.

  10. Daily hoarding opportunity entrains the pacemaker for hamster activity rhythms.

    PubMed

    Rusak, B; Mistlberger, R E; Losier, B; Jones, C H

    1988-12-01

    The effects on activity rhythms of a daily 30 min opportunity to leave the home cage and hoard seeds from an open field were assessed in Syrian hamsters housed in continuous dim illumination. Six of ten hamsters responded with clear entrainment of their activity rhythms to the hoarding opportunity, as demonstrated by responses to phase shifts and by the onset phase of subsequent freerunning rhythms. No entrainable component separate from the freerunning rhythm was ever observed. Two hamsters showed phase shifts in response to the hoarding opportunity, but they did not meet the criteria for stable entrainment, and two did not respond with noticeable changes in rhythmicity. Ablations of the suprachiasmatic nuclei (SCN) were attempted in three hamsters that had entrained stably to the hoarding time. The effects of partial lesions in two animals indicated that the entrained rhythm was controlled by the light-entrainable pacemaker represented by the SCN. The one animal with an apparently complete lesion, however, developed a clear, but irregular, increase in activity in anticipation of the daily hoarding time. SCN ablation apparently unmasked an oscillator system separate from the SCN and susceptible to entrainment by a nonphotic cue. The oscillator mechanism affected by daily hoarding opportunities in hamsters appears to be tightly coupled to the SCN pacemaker, in contrast to the system in rats that is synchronized by daily feeding schedules. PMID:3244126

  11. The behavioral theory of timing: Reinforcer rate determines pacemaker rate

    PubMed Central

    Bizo, Lewis A.; White, K. Geoffrey

    1994-01-01

    In the behavioral theory of timing, pulses from a hypothetical Poisson pacemaker produce transitions between states that are correlated with adjunctive behavior. The adjunctive behavior serves as a discriminative stimulus for temporal discriminations. The present experiments tested the assumption that the average interpulse time of the pacemaker is proportional to interreinforcer interval. Responses on a left key were reinforced at variable intervals for the first 25 s since the beginning of a 50-s trial, and right-key responses were reinforced at variable intervals during the second 25 s. Psychometric functions relating proportion of right-key responses to time since trial onset, in 5-s intervals across the 50-s trial, were sigmoidal in form. Average interpulse times derived by fitting quantitative predictions from the behavioral theory of timing to obtained psychometric functions decreased when the interreinforcer interval was decreased and increased when the interreinforcer interval was increased, as predicted by the theory. In a second experiment, average interpulse times estimated from trials without reinforcement followed global changes in interreinforcer interval, as predicted by the theory. Changes in temporal discrimination as a function of interreinforcer interval were therefore not influenced by the discrimination of reinforcer occurrence. The present data support the assumption of the behavioral theory of timing that interpulse time is determined by interreinforcer interval. PMID:16812723

  12. [Present status and future aspects of the respiratory pacemaker].

    PubMed

    Thoma, H; Girsch, W; Holle, J; Unger, E

    1997-04-28

    Under certain conditions, phrenic pacing is a rare but most effective and attractive alternative for long-term ventilation. General indications concern diseases of the breathing center, for example Undine's disease (loss of CO2 sensitivity) in infants and high cervical spinal cord lesions in the level of C0 to C3. Despite of the advantage of physiologic respiration mode (no positive air pressure) compared to long-term ventilation, the phrenic pacemaker enables high life quality for the patients due to possibilities of closing of tracheostoma (Vienna system), an optimum in mobility and high cost effectiveness. International research and development in this area concerns 1. nerve transposition of an innervated nerve to a denervating phrenic nerve, 2. additional stimulation of thoracal muscles for inspiration, 3. additional stimulation of expiration, 4. endoscopic operative positioning of the electrodes, 5. development of a pacer with sensor input for an individual respiration rhythm (controlled by the vocal cord) and 6. development of a fully implantable system Improvements of the present pacemaker system may lead to enlargement of indications, for example use in patients with severe nocturnal arrhythmias in respiration. PMID:9235482

  13. Phase shifting two coupled circadian pacemakers - Implications for jet lag

    NASA Technical Reports Server (NTRS)

    Gander, P. H.; Kronauer, R. E.; Graeber, R. C.

    1985-01-01

    Two Van der Pol oscillators with reciprocal linear velocity coupling are utilized to model the response of the human circadian timing system to abrupt displacements of the environmental time cues (zeitgebers). The core temperature rhythm and sleep-wake cycle simulated by the model are examined. The relationship between the masking of circadian rhythms by environmental variables and behavioral and physiological events and the rates of resynchronization is studied. The effects of zeitgeber phase shifts and zeitgeber strength on the resynchronization rates are analyzed. The influence of intrinsic pacemakers periods and coupling strength on resynchronization are investigated. The simulated data reveal that: resynchronization after a time zone shift depends on the magnitude of the shift; the time of day of the shift has little influence on resynchronization; the strength of zeitgebers affects the rate and direction of the resynchronization; the intrinsic pacemaker periods have a significant effect on resynchronization; and increasing the coupling between the oscillators results in an increase in the rate of resynchronization. The model data are compared to transmeridian flight studies data and similar resynchronization patterns are observed.

  14. Cardiac sarcoidosis

    PubMed Central

    Smedema, J.P.; Zondervan, P.E.; van Hagen, P.; ten Cate, F.J.; Bresser, P.; Doubell, A.F.; Pattynama, P.; Hoogsteden, H.C.; Balk, A.H.M.M.

    2002-01-01

    Sarcoidosis is a multi-system granulomatous disorder of unknown aetiology. Symptomatic cardiac involvement occurs in approximately 5% of patients. The prevalence of sarcoidosis in the Netherlands is unknown, but estimated to be approximately 20 per 100,000 population (3200 patients). We report on five patients who presented with different manifestations of cardiac sarcoidosis, and give a brief review on the current management of this condition. Magnetic Resonance Imaging (MRI) can be of great help in diagnosing this condition as well as in the follow-up of the response to therapy. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6 PMID:25696121

  15. Effects of tertiapin-Q and ZD7288 on changes in sinoatrial pacemaker rhythm during vagal stimulation.

    PubMed

    Han, Su Young; Bolter, Chris P

    2015-12-01

    Heart rate slowing produced by cardiac parasympathetic (vagal) stimulation is thought to be the result of modulation of the acetylcholine-activated K(+) current (IK,ACh) and the pacemaker current (If) in sinoatrial (SAN) pacemaker cells. However, the contribution of these and other ion currents to vagal slowing is controversial. Here, we examined the contributions of IK,ACh and If to vagal slowing in 15 isolated, vagal-innervated preparations of guinea-pig atria, using 300 nM tertiapin-Q (TQ) and 2 ?M ZD7288 to obtain full and substantial block of these currents, respectively. Blocking IK,ACh alone reduced atrial rate responses to 10-s trains of regular vagal stimulation (supramaximal stimulation, 2-ms duration, 1-10 Hz) by ~50% (P<0.01; N=11); blocking If alone had no effect (N=7). Blocking both IK,ACh and If produced ~90% reduction (P<0.01; N=4). Atrial cycle length response to a single burst of vagal stimuli (3 stimuli at 50 Hz), delivered at the optimum phase of the cycle was strongly suppressed by blocking IK,ACh (reduced by 98%; P<0.01; N=9), and modestly reduced by blocking If alone (by ~43%; P=0.20; N=6). The response was abolished by combined block of IK,ACh and If (P=0.04; N=4). Our data show that modulation of IK,ACh and If is sufficient to account for all the vagal slowing observed in this preparation. The vagally-induced negative shift in activation potential for If will be opposed by hyperpolarisation of SAN through activation of IK,ACh. Thus removal of IK,ACh by TQ may have exaggerated the overall contribution of If to vagal slowing. PMID:26549880

  16. Glocal Clinical Registries: Pacemaker Registry Design and Implementation for Global and Local Integration Methodology and Case Study

    PubMed Central

    da Silva, Ktia Regina; Costa, Roberto; Crevelari, Elizabeth Sartori; Lacerda, Marianna Sobral; de Moraes Albertini, Caio Marcos; Filho, Martino Martinelli; Santana, Jos Eduardo; Vissoci, Joo Ricardo Nickenig; Pietrobon, Ricardo; Barros, Jacson V.

    2013-01-01

    Background The ability to apply standard and interoperable solutions for implementing and managing medical registries as well as aggregate, reproduce, and access data sets from legacy formats and platforms to advanced standard formats and operating systems are crucial for both clinical healthcare and biomedical research settings. Purpose Our study describes a reproducible, highly scalable, standard framework for a device registry implementation addressing both local data quality components and global linking problems. Methods and Results We developed a device registry framework involving the following steps: (1) Data standards definition and representation of the research workflow, (2) Development of electronic case report forms using REDCap (Research Electronic Data Capture), (3) Data collection according to the clinical research workflow and, (4) Data augmentation by enriching the registry database with local electronic health records, governmental database and linked open data collections, (5) Data quality control and (6) Data dissemination through the registry Web site. Our registry adopted all applicable standardized data elements proposed by American College Cardiology / American Heart Association Clinical Data Standards, as well as variables derived from cardiac devices randomized trials and Clinical Data Interchange Standards Consortium. Local interoperability was performed between REDCap and data derived from Electronic Health Record system. The original data set was also augmented by incorporating the reimbursed values paid by the Brazilian government during a hospitalization for pacemaker implantation. By linking our registry to the open data collection repository Linked Clinical Trials (LinkedCT) we found 130 clinical trials which are potentially correlated with our pacemaker registry. Conclusion This study demonstrates how standard and reproducible solutions can be applied in the implementation of medical registries to constitute a re-usable framework. Such approach has the potential to facilitate data integration between healthcare and research settings, also being a useful framework to be used in other biomedical registries. PMID:23936257

  17. The new criterion for cardiac resynchronization therapy treatment assessed by two channels impedance cardiography

    NASA Astrophysics Data System (ADS)

    Peczalski, K.; Palko, T.; Wojciechowski, D.; Dunajski, Z.; Kowalewski, M.

    2013-04-01

    The cardiac resynchronization therapy is an effective treatment for systolic failure patients. Independent electrical stimulation of left and right ventricle corrects mechanical ventricular dyssynchrony. About 30-40% treated patients do not respond to therapy. In order to improve clinical outcome authors propose the two channels impedance cardiography for assessment of ventricular dyssynchrony. The proposed method is intended for validation of patients diagnosis and optimization of pacemaker settings for cardiac resynchronization therapy. The preliminary study has showed that bichannel impedance cardiography is a promising tool for assessment of ventricular dyssynchrony.

  18. Rhabdomyosarcoma associated with the lead wire of a pacemaker generator implant.

    PubMed

    Thieman Mankin, Kelley M; Dunbar, Mark D; Toplon, David; Ginn, Pamela; Maisenbacher, Herbert W; Risselada, Marije

    2014-06-01

    An 11-year-old female spayed Labrador Retriever was presented for a draining, painful subcutaneous mass palpated over a previously implanted pacemaker generator. Infection was suspected and the mass was removed surgically. On cut surface, the mass was friable and mottled tan to brown with firm pale tan nodules, surrounding the pacemaker lead wire adjacent to the pacemaker generator. Cytologic interpretation of impression smears was consistent with a sarcoma, and suggestive of a rhabdomyosarcoma due to the presence of strap-like cells. On histopathologic examination, a highly invasive nodular mass surrounded the pacemaker lead, composed of pleomorphic round, spindle and strap cells, and multinucleated giant cells. The population exhibited microscopic invasion into the deep portion of the fibrous capsule surrounding the pacemaker generator. There were tumor emboli within small to medium subcutaneous veins adjacent to the mass. Immunohistochemically, the neoplastic cells stained positive for ?-sarcomeric actin and vimentin, and negative for ?-smooth muscle actin, consistent with a rhabdomyosarcoma arising at the site of the pacemaker generator. To our knowledge, this is the first report of a rhabdomyosarcoma associated with the lead wire of a pacemaker generator in a dog. PMID:24654997

  19. Ocular clocks are tightly coupled and act as pacemakers in the circadian system of Japanese quail.

    PubMed

    Steele, Christopher T; Zivkovic, Bora D; Siopes, Thomas; Underwood, Herbert

    2003-01-01

    Our previous studies showed that the eyes of Japanese quail contain a biological clock that drives a daily rhythm of melatonin synthesis. Furthermore, we hypothesized that these ocular clocks are pacemakers because eye removal abolishes freerunning rhythms in constant darkness (DD). If the eyes are indeed acting as pacemakers, we predicted that the two ocular pacemakers in an individual bird must remain in phase in DD and, furthermore, the two ocular pacemakers would rapidly regain coupling after being forced out of phase. These predictions were confirmed by demonstrating that 1) the ocular melatonin rhythms of the two eyes maintained phase for at least 57 days in DD and 2) after ocular pacemakers were forced out of phase by alternately patching the eyes in constant light, two components of body temperature were observed that fused into a consolidated rhythm after 5-6 days in DD, showing pacemaker recoupling. The ability to maintain phase in DD and rapidly recouple after out-of-phase entrainment demonstrates that the eyes are strongly coupled pacemakers that work in synchrony to drive circadian rhythmicity in Japanese quail. PMID:12388441

  20. Current status of cardiac surgery: a 40 year review.

    PubMed

    Richenbacher, W E; Myers, J L; Waldhausen, J A

    1989-09-01

    Cardiac surgery has undergone dramatic advancements during the past 3 decades. The introduction of cardiopulmonary bypass and cardioplegic arrest ushered in the true era of open heart surgery. Bioprostheses and mechanical valves as well as techniques for valve reconstruction permit routine repair or replacement of stenotic and regurgitant native valves. Progress in the disciplines of mechanical and electrical engineering has led to the development of pocket watch-sized, physiologically responsive pacemakers as well as a variety of circulatory assist devices that include the intraaortic balloon pump, ventricular assist device and total artificial heart. The synthesis of cardiotonic and vasoactive drugs and advancements in anesthetic management, postoperative monitoring and nursing care greatly facilitate perioperative patient management. This summary of state of the art cardiac surgery begins with a brief historical background followed by a review of recent advances in six main categories: coronary artery disease, acquired valvular heart disease, congenital cardiac disease, cardiac transplantation, myocardial preservation and mechanical circulatory assistance. In conducting the review of recent literature, particular attention was directed to large clinical series that document the results of contemporary surgical procedures, novel therapeutic approaches to current clinical problems and unresolved controversies in the field of cardiac surgery. The abundance of surgical literature and constraints on the length of this article do not permit an exhaustive review. Apologies are extended to clinicians and laboratory investigators whose important contributions to the understanding and treatment of cardiac disease are not included herein. PMID:2671092