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Sample records for cardiac pacemaker program

  1. Generation of cardiac pacemaker cells by programming and differentiation.

    PubMed

    Husse, Britta; Franz, Wolfgang-Michael

    2016-07-01

    A number of diseases are caused by faulty function of the cardiac pacemaker and described as "sick sinus syndrome". The medical treatment of sick sinus syndrome with electrical pacemaker implants in the diseased heart includes risks. These problems may be overcome via "biological pacemaker" derived from different adult cardiac cells or pluripotent stem cells. The generation of cardiac pacemaker cells requires the understanding of the pacing automaticity. Two characteristic phenomena the "membrane-clock" and the "Ca(2+)-clock" are responsible for the modulation of the pacemaker activity. Processes in the "membrane-clock" generating the spontaneous pacemaker firing are based on the voltage-sensitive membrane ion channel activity starting with slow diastolic depolarization and discharging in the action potential. The influence of the intracellular Ca(2+) modulating the pacemaker activity is characterized by the "Ca(2+)-clock". The generation of pacemaker cells started with the reprogramming of adult cardiac cells by targeted induction of one pacemaker function like HCN1-4 overexpression and enclosed in an activation of single pacemaker specific transcription factors. Reprogramming of adult cardiac cells with the transcription factor Tbx18 created cardiac cells with characteristic features of cardiac pacemaker cells. Another key transcription factor is Tbx3 specifically expressed in the cardiac conduction system including the sinoatrial node and sufficient for the induction of the cardiac pacemaker gene program. For a successful cell therapeutic practice, the generated cells should have all regulating mechanisms of cardiac pacemaker cells. Otherwise, the generated pacemaker cells serve only as investigating model for the fundamental research or as drug testing model for new antiarrhythmics. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.

  2. 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.

  3. 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

  4. Trends in cardiac pacemaker batteries.

    PubMed

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

    2004-10-01

    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.

  5. [Future cardiac pacemakers – technical visions].

    PubMed

    Haeberlin, Andreas; Zurbuchen, Adrian; Pfenniger, Aloïs; Fuhrer, Jürg; 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 today’s systems.

  6. [Cardiac Pacemakers, implantable defibrillators and IRM].

    PubMed

    Frank, R; Hidden-Lucet, F; Himbert, C; Petitot, J C; Fontaine, G

    2003-04-01

    The IRM is formally contraindicated to the pacemaker and cardiac defibrillator wearers because of the risk of inhibition or inappropriate stimulations during the examination. However if the examination is essential, suitable programming of the apparatus and a constant monitoring of the heartbeat rate by a qualified doctor in cardiac stimulation must make it possible to avoid any accident.

  7. Programming of sensor driven pacemakers.

    PubMed

    Strobel, J S; Kay, G N

    2000-02-01

    The chronotropic response is the most important means by which cardiac output is increased and oxygen delivery is maintained in response to increased oxygen consumption during exercise or stress. When the chronotropic response is suboptimal or absent, exercise intolerance results. This condition, called chronotropic incompetence can be treated effectively with a sensor-driven rate-responsive pacemaker. The effectiveness of this therapy assumes that the pacemaker is programmed appropriately. This article focuses on the programming of sensor-driven pacemakers and provides additional suggestions for follow-up testing to ensure maximal benefit from these devices.

  8. 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.

  9. 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

  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. Pacemaker leads and cardiac perforation

    PubMed Central

    Prasad, Rachana; Andrews, Richard

    2017-01-01

    This case series highlights the rare but potentially life threatening complication of ventricular perforation caused by pacemaker leads and discusses appropriate investigations and management strategies. PMID:28321317

  12. Sacral Neuromodulation in Patients With a Cardiac Pacemaker

    PubMed Central

    2016-01-01

    The objective of this study was to describe our experience using sacral neuromodulation to treat urinary urgency, frequency, urge incontinence, and chronic urinary retention in patients with cardiac pacemakers. With the increasingly widespread use of InterStim for bladder function restoration, we are seeing more complex patients with multiple comorbidities, including cardiac conditions. Herein, we report 3 cases of individuals with cardiac pacemakers who underwent InterStim implantation to treat urinary conditions. This study is a case series of 3 patients with cardiac pacemakers who underwent sacral neuromodulation to treat refractory voiding dysfunction. The initial patient screening for InterStim therapy involved percutaneous nerve evaluation (PNE), in which a temporary untined lead wire was placed through the S3 foramen. Patients who did not respond to PNE proceeded to a staged implant. All patients in this study had a greater than 50% improvement of their urinary symptoms during the initial trial and underwent placement of the InterStim implantable pulse generator (IPG). Postoperative programming was done under electrocardiogram monitoring by a cardiologist. No interference was observed between the Inter-Stim IPG and the cardiac pacemaker. In this group of patients, sacral neuromodulation in the presence of a cardiac pacemaker appears to have been safe. PMID:27706012

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

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false External transcutaneous cardiac pacemaker... § 870.5550 External transcutaneous cardiac pacemaker (noninvasive). (a) Identification. An external transcutaneous cardiac pacemaker (noninvasive) is a device used to supply a periodic electrical pulse intended...

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

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false External transcutaneous cardiac pacemaker... § 870.5550 External transcutaneous cardiac pacemaker (noninvasive). (a) Identification. An external transcutaneous cardiac pacemaker (noninvasive) is a device used to supply a periodic electrical pulse intended...

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

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false External transcutaneous cardiac pacemaker... § 870.5550 External transcutaneous cardiac pacemaker (noninvasive). (a) Identification. An external transcutaneous cardiac pacemaker (noninvasive) is a device used to supply a periodic electrical pulse intended...

  16. Medical devices; revocation of cardiac pacemaker registry. Food and Drug Administration, HHS. Final rule.

    PubMed

    1999-11-24

    The Food and Drug Administration (FDA) is issuing a final rule to revoke a regulation requiring a cardiac pacemaker registry. The registry, which was mandated by the Deficit Reduction Act of 1984, requires any physician and any provider of services who requests or receives Medicare payment for an implantation, removal, or replacement of permanent cardiac pacemaker devices and pacemaker leads to submit certain information to the registry. The information is used by FDA to track the performance of permanent cardiac pacemakers and pacemaker leads and by the Health Care Finance Administration (HCFA) to administer its Medicare payment program for these devices. This action is being taken to implement an act to Repeal An Unnecessary Medical Device Reporting Requirement passed by Congress in 1996 to remove the cardiac pacemaker registry to eliminate duplicative and unnecessary reporting.

  17. 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.

  18. 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.

  19. Pacemaker stimulus amplitude alteration without loss of capture: an unusual ECG finding in cardiac tamponade from pacemaker lead perforation.

    PubMed

    Suksaranjit, P; Prasidthrathsint, K

    2014-01-01

    A variation in pacemaker stimulus amplitude can represent pacemaker system dysfunction from generator malfunction, lead insulation defect, lead fracture, or artefact of digital signal processing of the electrocardiography recorder. Pacemaker lead perforation into the pericardial space typically results in loss of capture which was not demonstrated in our patient. In summary, we report an unusual ECG finding of pacemaker stimulus amplitude alteration without loss of capture in the setting of cardiac tamponade from pacemaker lead perforation.

  20. 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

  1. 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

  2. Emergency room and inpatient use after cardiac pacemaker implantation.

    PubMed

    Sloan, Frank Allen; George, Linda Kaufman; Hu, Linyan

    2013-02-15

    Although studies have demonstrated health benefits, there is limited evidence on utilization and cost changes associated with cardiac pacemaker implantation from national community samples. The aim of this study was to quantify changes in emergency room (ER) and hospital inpatient use and in Medicare payments per beneficiary/year after pacemaker implantation. Outcomes for pacemaker recipients after and before implantation and between pacemaker recipients and controls were compared using propensity score matching. Data came from Health and Retirement Study interviews merged with Medicare claims. Sample subjects were aged ≥68 years with diagnosed conduction disorders or cardiac dysrhythmias in the previous 3 years. Outcome measures were (1) ER visits, inpatient admissions and days, and Medicare payments for ER and inpatient care in the after period for the pacemaker versus control groups, defined per beneficiary/year, (2) difference in differences in the same 5 outcome variables, and (3) binary variables for whether or not utilization or payments were lower in the after versus before periods for the pacemaker versus control groups. In conclusion, most pacemaker recipients improved, as measured by reductions in use and payments in the after versus before period, and there were reductions in ER visits and hospital admissions for conditions commonly leading to pacemaker implantation.

  3. 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.

  4. Acute pericarditis with cardiac tamponade induced by pacemaker implantation.

    PubMed

    Shingaki, Masami; Kobayashi, Yutaka; Suzuki, Haruo

    2015-11-01

    An 87-year-old woman was diagnosed with third-degree atrioventricular block and underwent pacemaker implantation. On postoperative day 12, she experienced cardiac tamponade that was suspected on computed tomography to be caused by lead perforation; therefore, we performed open-heart surgery. However, we could not identify a perforation site on the heart, and drained a 400-mL exudative pericardial effusion. Subsequently, we diagnosed the pericardial effusion as due to pericarditis induced by pacemaker implantation. It is sometimes difficult to distinguish pericarditis from pacemaker lead perforation, so both should be included in the differential diagnosis.

  5. 21 CFR 870.5550 - External transcutaneous cardiac pacemaker (noninvasive).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false External transcutaneous cardiac pacemaker (noninvasive). 870.5550 Section 870.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... pace the heart. The pulse from the device is usually applied to the surface of the chest...

  6. 21 CFR 870.5550 - External transcutaneous cardiac pacemaker (noninvasive).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false External transcutaneous cardiac pacemaker (noninvasive). 870.5550 Section 870.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... pace the heart. The pulse from the device is usually applied to the surface of the chest...

  7. The pacemaker current in cardiac Purkinje myocytes

    PubMed Central

    1995-01-01

    It is generally assumed that in cardiac Purkinje fibers the hyperpolarization activated inward current i(f) underlies the pacemaker potential. Because some findings are at odds with this interpretation, we used the whole cell patch clamp method to study the currents in the voltage range of diastolic depolarization in single canine Purkinje myocytes, a preparation where many confounding limitations can be avoided. In Tyrode solution ([K+]o = 5.4 mM), hyperpolarizing steps from Vh = -50 mV resulted in a time-dependent inwardly increasing current in the voltage range of diastolic depolarization. This time- dependent current (iKdd) appeared around -60 mV and reversed near EK. Small superimposed hyperpolarizing steps (5 mV) applied during the voltage clamp step showed that the slope conductance decreases during the development of this time-dependent current. Decreasing [K+]o from 5.4 to 2.7 mM shifted the reversal potential to a more negative value, near the corresponding EK. Increasing [K+]o to 10.8 mM almost abolished iKdd. Cs+ (2 mM) markedly reduced or blocked the time-dependent current at potentials positive and negative to EK. Ba2+ (4 mM) abolished the time-dependent current in its usual range of potentials and unmasked another time-dependent current (presumably i(f)) with a threshold of approximately -90 mV (> 20 mV negative to that of the time-dependent current in Tyrode solution). During more negative steps, i(f) increased in size and did not reverse. During i(f) the slope conductance measured with small (8-10 mV) superimposed clamp steps increased. High [K+]o (10.8 mM) markedly increased and Cs+ (2 mM) blocked i(f). We conclude that: (a) in the absence of Ba2+, a time-dependent current does reverse near EK and its reversal is unrelated to K+ depletion; (b) the slope conductance of that time-dependent current decreases in the absence of K+ depletion at potentials positive to EK where inactivation of iK1 is unlikely to occur. (c) Ba2+ blocks this time

  8. 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.

  9. Integrative Modeling of Electrical Properties of Pacemaker Cardiac Cells

    NASA Astrophysics Data System (ADS)

    Grigoriev, M.; Babich, L.

    2016-06-01

    This work represents modeling of electrical properties of pacemaker (sinus) cardiac cells. Special attention is paid to electrical potential arising from transmembrane current of Na+, K+ and Ca2+ ions. This potential is calculated using the NaCaX model. In this respect, molar concentration of ions in the intercellular space which is calculated on the basis of the GENTEX model is essential. Combined use of two different models allows referring this approach to integrative modeling.

  10. Plethyzmography in assessment of hemodynamic results of pacemaker functions programming

    NASA Astrophysics Data System (ADS)

    Wojciechowski, Dariusz; Sionek, Piotr; Peczalski, Kazimierz; Janusek, Dariusz

    2011-01-01

    The paper presents potential role of plethyzmography in optimization of heart hemodynamic function during pacemaker programming. The assessment of optimal stroke volume in patients, with implanted dual chamber pacemaker (DDD), by plethyzmography was a goal of the study. The data were collected during pacing rhythm. 20 patients (8 female and 12 male, average 77.4+/-4.6 years) with dual chamber pacemaker (DDD) and with pacing rhythm during routine pacemaker control and study tests were incorporated in the study group. Hemodynamic parameters were assessed during modification of atrio-ventricular delay (AVD) for pacing rhythm of 70 bpm and 90 bpm. The time of atrioventricular was programmed with 20 ms steps within range 100-200 ms and data were recorded with two minutes delay between two consecutive measurements. Stroke volume (SV) and cardiac output (CO) were calculated from plethyzmographic signal by using Beatscope software (TNO Holand). Highest SV calculated for given pacing rhythm was named optimal stroke volume (OSV) and consequently highest cardiac output was named maximal cardiac output (MCO). The time of atrio-ventricular delay for OSV was named optimal atrioventricular delay (OAVD). The results have showed: mean values of OAVD for 70 bpm - 152+/-33 ms and for 90 bpm -149+/-35 ms, shortening of the mean OAVD time caused by increase of pacing rate from 70 bpm to 90 bpm what resulted in statistically significant decrease of OSV with not statistically significant increase of MCO. The analysis of consecutive patients revealed three types of response to increase of pacing rhythm: 1. typical-shortening of OAVD, 2. neutral-no change of OAVD and 3.atypical-lengthening of OAVD.

  11. Direct activation of cardiac pacemaker channels by intracellular cyclic AMP.

    PubMed

    DiFrancesco, D; Tortora, P

    1991-05-09

    Cyclic AMP acts as a second messenger in the modulation of several ion channels that are typically controlled by a phosphorylation process. In cardiac pacemaker cells, adrenaline and acetylcholine regulate the hyperpolarization-activated current (if), but in opposite ways; this current is involved in the generation and modulation of pacemaker activity. These actions are mediated by cAMP and underlie control of spontaneous rate by neurotransmitters. Whether the cAMP modulation of if is mediated by channel phosphorylation is, however, still unknown. Here we investigate the action of cAMP on if in excised patches of cardiac pacemaker cells and find that cAMP activates if by a mechanism independent of phosphorylation, involving a direct interaction with the channels at their cytoplasmic side. Cyclic AMP activates if by shifting its activation curve to more positive voltages, in agreement with whole-cell results. This is the first evidence of an ion channel whose gating is dually regulated by voltage and direct cAMP binding.

  12. 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

  13. Cardiac magnetic resonance imaging of a patient with an magnetic resonance imaging conditional permanent pacemaker

    PubMed Central

    Hogarth, Andrew J.; Artis, Nigel J.; Sivananthan, U. Mohan; Pepper, Chris B.

    2011-01-01

    Cardiac magnetic resonance imaging (MRI) is increasingly used as the optimum modality for cardiac imaging. An aging population and rising numbers of patients with permanent pacemakers means many such individuals may require cardiac MRI scanning in the future. Whilst the presence of a permanent pacemaker is historically regarded as a contra-indication to MRI scanning, pacemaker systems have been developed to limit any associated risks. No reports have been published regarding the use of such devices with cardiac MRI in a clinical setting. We present the safe, successful cardiac MRI scan of a patient with an MRI-conditional permanent pacing system. PMID:22355486

  14. Reuse of pacemakers, defibrillators and cardiac resynchronisation devices

    PubMed Central

    Sakthivel, R; Satheesh, Santhosh; Ananthakrishna Pillai, Ajith; Sagnol, Pascal; Jouven, Xavier; Dodinot, Bernard; Balachander, Jayaraman

    2017-01-01

    Objective Access to pacemakers remains poor among many patients in low/middle-income countries. Reuse of explanted pacemakers is a possible solution, but is still not widespread because of concerns regarding outcomes, especially infection. Our objective was to study early outcomes with implants using reused devices and compare them with those with implants using new devices. Methods We studied all patients who underwent implantation of a new or reused pacemaker, cardiac resynchronisation therapy (CRT) device or implantable cardioverter defibrillator (ICD) in the last 5 years at a single institution. We analysed outcomes related to infection, device malfunction and device-related death within 6 months after initial implantation. Results During the study period, 887 patients underwent device implant, including 127 CRT devices or ICDs. Of these, 260 devices (29.3%) were reused and the others were new. At 6 months, there were three device-related infections in implants using a new device. There were no infections among patients receiving a reused device. There were no device malfunctions or device-related deaths in either group. Conclusions We found no difference in rate of infection or device malfunction among patients getting a reused device as compared with those with a new device. This study reinforces the safety of reusing devices for implant including CRT and ICDs. PMID:28176981

  15. [Extracorporeal shock wave lithotripsy for ureteral stone in patient with implanted cardiac pacemaker: a case report].

    PubMed

    Kato, Yuji; Hou, Kyokushin; Hori, Junichi; Taniguchi, Narumi; Yamaguchi, Satoshi; Yachiku, Sunao; Azumi, Makoto; Osanai, Hiroaki

    2003-09-01

    We report a case of extracorporeal shock wave lithotripsy (SWL) for ureteral stone in patient with implanted cardiac pacemaker. A 68-year-old woman was admitted to our hospital for left back pain due to left single ureteral stone (13 x 7 mm) in 2002. A permanent cardiac pacemaker has been implanted for sick sinus syndrome in 1997. After evaluation for cardiac function and pacemaker function by a cardiologist and a pacemaker technician, SWL (MFL 5000, Dornier) was performed without changing pacemaker mode (DDD mode). Shock waves were incorrectly exposed a few time triggered by arterial pacing amplitude, but no cardiovascular event or malfunction of the pacemaker was occurred during or after SWL. The ureteral stone was successfully fragmented with 2,400 shock waves (24 kV) and the fragments were delivered immediately.

  16. 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.

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

    PubMed

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

    2015-01-01

    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.

  18. 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.

  19. Pacemaker

    MedlinePlus

    ... the Risks Lifestyle Clinical Trials Links Related Topics Arrhythmia Atrial Fibrillation Heart Block Implantable Cardioverter Defibrillators Long ... a normal rate. Pacemakers are used to treat arrhythmias (ah-RITH-me-ahs). Arrhythmias are problems with ...

  20. Management of radiation therapy patients with cardiac defibrillator or pacemaker.

    PubMed

    Salerno, Francesca; Gomellini, Sara; Caruso, Cristina; Barbara, Raffaele; Musio, Daniela; Coppi, Tamara; Cardinale, Mario; Tombolini, Vincenzo; de Paula, Ugo

    2016-06-01

    The increasing growth of population with cardiac implantable electronic devices (CIEDs) such as Pacemaker (PM) and Implantable Cardiac Defibrillators (ICD), requires particular attention in management of patients needing radiation treatment. This paper updates and summarizes some recommendations from different international guidelines. Ionizing radiation and/or electromagnetic interferences could cause device failure. Current approaches to treatment in patients who have these devices vary among radiation oncology centres. We refer to the German Society of Radiation Oncology and Cardiology guidelines (ed. 2015); to the Society of Cardiology Australia and New Zealand Statement (ed. 2015); to the guidelines in force in the Netherlands (ed. 2012) and to the Italian Association of Radiation Oncology recommendations (ed. 2013) as reported in the guidelines for the treatment of breast cancer in patients with CIED. Although there is not a clear cut-off point, risk of device failure increases with increasing doses. Cumulative dose and pacing dependency have been combined to categorize patients into low-, medium- and high-risk groups. Measures to secure patient safety are described for each category. The use of energy ≤6MV is preferable and it's strongly recommended not to exceed a total dose of 2 Gy to the PM and 1 Gy for ICD. Given the dangers of device malfunction, radiation oncology departments should adopt all the measures designed to minimize the risk to patients. For this reason, a close collaboration between cardiologist, radiotherapist and physicist is necessary.

  1. 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.

  2. Tbx18-dependent differentiation of brown adipose tissue-derived stem cells toward cardiac pacemaker cells.

    PubMed

    Chen, Lei; Deng, Zi-Jun; Zhou, Jian-Sheng; Ji, Rui-Juan; Zhang, Xi; Zhang, Chuan-Sen; Li, Yu-Quan; Yang, Xiang-Qun

    2017-04-05

    A cell-sourced biological pacemaker is a promising therapeutic approach for sick sinus syndrome (SSS) or severe atrial ventricular block (AVB). Adipose tissue-derived stem cells (ATSCs), which are optimal candidate cells for possible use in regenerative therapy for acute or chronic myocardial injury, have the potential to differentiate into spontaneous beating cardiomyocytes. However, the pacemaker characteristics of the beating cells need to be confirmed, and little is known about the underlying differential mechanism. In this study, we found that brown adipose tissue-derived stem cells (BATSCs) in mice could differentiate into spontaneous beating cells in 15% FBS Dulbecco's modified Eagle's medium (DMEM) without additional treatment. Subsequently, we provide additional evidence, including data regarding ultrastructure, protein expression, electrophysiology, and pharmacology, to support the differentiation of BATSCs into a cardiac pacemaker phenotype during the course of early cultivation. Furthermore, we found that silencing Tbx18, a key transcription factor in the development of pacemaker cells, terminated the differentiation of BATSCs into a pacemaker phenotype, suggesting that Tbx18 is required to direct BATSCs toward a cardiac pacemaker fate. The expression of Tbx3 and shox2, the other two important transcription factors in the development of pacemaker cells, was decreased by silencing Tbx18, which suggests that Tbx18 mediates the differentiation of BATSCs into a pacemaker phenotype via these two downstream transcription factors.

  3. Septic Pulmonary Embolism Caused by Infected Pacemaker Leads After Replacement of a Cardiac Resynchronization Therapy Device

    PubMed Central

    Said, Salah A.M.; Nijhuis, Rogier; Derks, Anita; Droste, Herman

    2016-01-01

    Patient: Male, 70 Final Diagnosis: Pacemaker leads endocarditis Symptoms: Bacterial lead endocarditis • congestive heart failure • fever • pacemaker dysfunction Medication: — Clinical Procedure: Pacemaker box replacement due to end-of-service Specialty: Cardiology Objective: Unusual clinical course Background: Cardiac resynchronization therapy (CRT) has been demonstrated to reduce morbidity and mortality in patients with advanced, drug-refractory heart failure. Procedure-related mortality is less than 1% in larger studies. Approximately10% of CRT patients have to undergo surgical revision because of infections, dislocations, or unacceptable electrical behavior manifested as high threshold, unstable sensing, or unwanted phrenic nerve stimulation. Case Report: A 70-year-old man with symptomatic congestive heart failure underwent implantation of a biventricular pacemaker on the left anterior chest wall in 2003 and pulse generator exchange in August 2009. The patient responded well to CRT. At follow-up, the pacing system functioned normally. In September 2009, in the context of a predialysis program, an abdominal computed tomography (CT) scan was performed in another hospital for assessment and evaluation of chronic kidney disease. This procedure was complicated with peripheral thrombophlebitis that was managed appropriately with complete recovery. Eight months later (May 2010), the patient was admitted to our hospital with fever, anemia, and elevated infection parameters. During admission, blood cultures grew Staphylococcus epidermidis. The chest X-ray, lung perfusion scintigraphy, and CT scan depicted pulmonary embolism and infarction. The right ventricular lead threshold was found to be increased to 7 volts with unsuccessful capture. Echocardiography demonstrated vegetations on leads. The entire pacing system was explanted, but the patient expired few days later following percutaneous removal due to multiorgan failure. Conclusions: In heart failure

  4. 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.

  5. 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.

  6. 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.

  7. [Dual-chamber rate-regulated cardiac pacing is aiming toward automatic pacemakers].

    PubMed

    Novák, M; Psenicka, M; Smola, M; Bríza, J; Cermák, S

    1997-11-01

    DDDR cardiac pacemakers meet the demand of the two main goals of modern cardiac pacing enauring both the synchronization of atriums and ventricles and the frequency response to physical exercise. In this way they simulate the normal heart rhythm behaviour best of all pacemakers in use. Since 1992 through 1995 the DDDR pacemakers were implanted in 27 patients aged 20-79 (mean 59.9) years in our pacemaker centre. The follow-up period has amounted to 46 months. 26 patients suffered from advanced sinus syndrome with the chronotropic incompetence and with the atrioventricular block, the remaining young man was given the pacemaker because of congenital atrioventricular block. In one patient epicardial leads implanted by thoracotomy have been used. After the wound had healed and the pulse energy had been reduced, the pacemaker bearers underwent the stepwise symptoms limited bicycle or treadmill stress test. During the follow-up the incidence of particular complications was assessed. In comparison with the DDD mode without the sensor, the DDDR pacemakers exhibiting the rate adaptation did improve the working capacity in particular patients in the stress test. (Tab. 1, Fig. 5, Ref. 16).

  8. Electromagnetic compatibility study of the in-vitro interaction of wireless phones with cardiac pacemakers.

    PubMed

    Schlegel, R E; Grant, F H; Raman, S; Reynolds, D

    1998-01-01

    This large-scale in-vitro investigation of the interaction between hand-held wireless phones and cardiac pacemakers tested 29 pacemaker models with five different phone standards. The phones were operational and suspended on a grid above a torso simulator filled with a saline bath with the pacemaker submerged at 0.5 cm. Testing consisted of 8,296 runs, during which any interactions detected were classified by type and regularity. Only a few pacemakers were responsible for a disproportionately large number of interactions. Likewise, interactions occurred during 21% of the tests using one particular phone technology, with little or no interaction resulting from use of the other standards. Other significant factors included the relative orientation of the phone and the pacemaker case, as well as the presence or absence of an injected ECG signal. The ECG signal facilitated observation of certain forms of interaction to the extent that this study indicates the importance of including an injected ECG signal in all testing. The study also supports the recommendation to maintain a separation distance of at least 6 inches between pacemakers and wireless phones. Each pacemaker reverted to its normal operation when the phone creating an interaction was turned off. This study may be useful in ongoing efforts to define test protocols, evaluate pacemaker designs, and mitigate interactions, perhaps providing the basis for future certification and screening efforts.

  9. Electromagnetic interference of implantable unipolar cardiac pacemakers by an induction oven.

    PubMed

    Hirose, Minoru; Hida, Mizuho; Sato, Eiji; Kokubo, Kenichi; Nie, Masaki; Kobayashi, Hirosuke

    2005-06-01

    Induction ovens have been reported to exert electromagnetic interference on implanted cardiac pacemakers. In an attempt to quantitatively investigate the electromagnetic interference caused by an induction oven on implantable unipolar cardiac pacemakers, we measured the distribution profile of the magnetic field intensity, both with and without a pan on the induction oven. We also performed the inhibition test and asynchronous test using four kinds of pacemakers housed in the standardized Irnich human body model, and measured the maximal distance from the induction oven up to which the interference occurred. In the pan-detection mode of the oven in the absence of a pan, the distribution profile of the magnetic field intensity peaked at the center of the cooking plate, and during induction heating of a pan placed on the induction oven, it was the largest at the circular top-edge of the pan. Pacemaker pulses were inhibited by the induction oven, or generated by the reversion mechanism. The maximal interference distance from the oven was 34 cm for one of the pacemakers. Thus, the safe distance from an induction oven of a patient with an implanted cardiac pacemaker is considered to be 50 cm or more. In conclusion, in the pan-detection mode of the oven in the absence of a pan, the distribution profile of the magnetic field intensity peaked at the center of the cooking plate, and during the induction heating of a pan placed on the oven, it peaked at the circular edge of the pan. The induction oven asynchronized or generated pulses in implantable unipolar cardiac pacemakers up to a maximal distance of 34 cm from the induction oven.

  10. Ethics and the cardiac pacemaker: more than just end-of-life issues.

    PubMed

    Hutchison, Katrina; Sparrow, Robert

    2017-04-06

    For many years, ethical debate about pacemakers has focused on whether and under what circumstances they may be turned off in end of life care. Several other important ethical issues have been neglected, perhaps because the dilemmas they pose for cardiologists are not so immediate. These include: potential conflicts of interest, particularly those arising from the role of industry employed allied professionals (IEAPs) in pacemaker care; unanticipated impacts of commercial competition and the device improvement cycle; risks associated with remotely accessible software; equity in access to healthcare; and questions about reuse of explanted pacemakers in low and middle income countries. This paper analyses these issues in order to facilitate a more comprehensive approach to ethics and the cardiac pacemaker. Cardiologists should be aware of all of these issues and contribute to ongoing discussions about how they are resolved.

  11. Interference of neodymium magnets with cardiac pacemakers and implantable cardioverter-defibrillators: an in vitro study.

    PubMed

    Ryf, Salome; Wolber, Thomas; Duru, Firat; Luechinger, Roger

    2008-01-01

    Permanent magnets may interfere with the function of cardiac pacemakers and implantable cardioverter-defibrillators (ICDs). Neodymium-iron-boron (NdFeB) magnets have become widely available in recent years and are incorporated in various articles of daily life. We conducted an in-vitro study to evaluate the ability of NdFeB magnets for home and office use to cause interference with cardiac pacemakers and ICDs. The magnetic fields of ten NdFeB magnets of different size and shape were measured at increasing distances beginning from the surface until a field-strength (B-field) value of 0.5 mT was reached. Furthermore, for each magnet the distance was determined at which a sample pacemaker switched from magnet mode to normal mode. Depending on the size and remanence of individual magnets, a B-field value of 0.5 mT was found at distances ranging from 1.5 cm to 30 cm and a value of 1 mT at distances from 1 cm to 22 cm. The pacemaker behavior was influenced at distances from 1 cm to 24 cm. NdFeB magnets for home and office use may cause interference with cardiac pacemakers and ICDs at distances up to 24 centimeters. Patient education and product declarations should include information about the risk associated with these magnets.

  12. 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

  13. 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.

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

    PubMed Central

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

    2014-01-01

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

  15. 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; Viščor, Ivo; Jurák, Pavel; Halámek, 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.

  16. Popeye domain containing proteins are essential for stress-mediated modulation of cardiac pacemaking in mice

    PubMed Central

    Froese, Alexander; Breher, Stephanie S.; Waldeyer, Christoph; Schindler, Roland F.R.; Nikolaev, Viacheslav O.; Rinné, Susanne; Wischmeyer, Erhard; Schlueter, Jan; Becher, Jan; Simrick, Subreena; Vauti, Franz; Kuhtz, Juliane; Meister, Patrick; Kreissl, Sonja; Torlopp, Angela; Liebig, Sonja K.; Laakmann, Sandra; Müller, Thomas D.; Neumann, Joachim; Stieber, Juliane; Ludwig, Andreas; Maier, Sebastian K.; Decher, Niels; Arnold, Hans-Henning; Kirchhof, Paulus; Fabritz, Larissa; Brand, Thomas

    2012-01-01

    Cardiac pacemaker cells create rhythmic pulses that control heart rate; pacemaker dysfunction is a prevalent disorder in the elderly, but little is known about the underlying molecular causes. Popeye domain containing (Popdc) genes encode membrane proteins with high expression levels in cardiac myocytes and specifically in the cardiac pacemaking and conduction system. Here, we report the phenotypic analysis of mice deficient in Popdc1 or Popdc2. ECG analysis revealed severe sinus node dysfunction when freely roaming mutant animals were subjected to physical or mental stress. In both mutants, bradyarrhythmia developed in an age-dependent manner. Furthermore, we found that the conserved Popeye domain functioned as a high-affinity cAMP-binding site. Popdc proteins interacted with the potassium channel TREK-1, which led to increased cell surface expression and enhanced current density, both of which were negatively modulated by cAMP. These data indicate that Popdc proteins have an important regulatory function in heart rate dynamics that is mediated, at least in part, through cAMP binding. Mice with mutant Popdc1 and Popdc2 alleles are therefore useful models for the dissection of the mechanisms causing pacemaker dysfunction and could aid in the development of strategies for therapeutic intervention. PMID:22354168

  17. [Interferences and cardiac pacemakers--defibrillators. Results of in vivo experiments and radio frequencies].

    PubMed

    Trigano, J A

    2003-04-01

    Interference with cardiac pacemakers and defibrillators by cellular phone and electronic article surveillance systems is shown in experimental studies with disparate findings. Interaction occurrence in real life is a convincing but rare experience. Device model, distance, power output and technology of the source are different and sometimes uncontrollable factors. As a result it remains difficult to quantify the true incidence of interaction and associated health risk. Nevertheless, simple recommendations commonly help the patients to prevent the interference.

  18. 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.

  19. MR Imaging in Patients with Cardiac Pacemakers and Implantable Cardioverter Defibrillators.

    PubMed

    Sommer, Torsten; Bauer, Wolfgang; Fischbach, Katharina; Kolb, Christof; Luechinger, Roger; Wiegand, Uwe; Lotz, Joachim; Eitel, Ingo; Gutberlet, Matthias; Thiele, Holger; Schild, Hans H; Kelm, Malte; Quick, Harald H; Schulz-Menger, Jeanette; Barkhausen, Jörg; Bänsch, Dietmar

    2017-02-15

    This joint consensus paper of the German Roentgen Society and the German Cardiac Society provides physical and electrophysiological background information and specific recommendations for the procedural management of patients with cardiac pacemakers (PM) and implantable cardioverter defibrillators (ICD) undergoing magnetic resonance (MR) imaging. The paper outlines the responsibilities of radiologists and cardiologists regarding patient education, indications, and monitoring with modification of MR sequences and PM/ICD reprogramming strategies being discussed in particular. The aim is to optimize patient safety and to improve legal clarity in order to facilitate the access of SM/ICD patients to MR imaging. Key Points:  · Conventional PM and ICD systems are no longer an absolute but rather a relative contraindication for performing an MR examination. Procedural management includes the assessment of the individual risk/benefit ratio, comprehensive patient informed consent about specific risks and "off label" use, extensive PM/ICD-related and MR-related safety precautions to reduce these risks to the greatest extent possible, as well as adequate monitoring techniques.. · MR conditional pacemaker and ICD systems have been tested and approved for MR examination under specific conditions ("in-label" use). Precise understanding of and compliance with the terms of use for the specific pacemaker system are essential for patient safety.. · The risk for an ICD patient during MR examinations is to be considered significantly higher compared to PM patients due to the higher vulnerability of the structurally damaged myocardium and the higher risk of irreversible damage to conventional ICD systems. The indication for a MR examination of an ICD patient should therefore be determined on a stricter basis and the expected risk/benefit ratio should be critically reviewed.. · This complex subject requires close collaboration between radiology and cardiology.. Citation Format

  20. How to program rate responsive pacemakers.

    PubMed

    Greco, E M; Guardini, S; Ferrario, M; Romano, S

    2000-02-01

    Because oxygen uptake (VO2) increases linearly with heart rate during exercise, the oxygen pulse reserve (OPR) method (VO2 reserve divided by heart rate reserve) may provide a valid guide for rate responsive parameter tailoring. Using custom-made software (Pacing Rate Profile Software [PRPS]) it is possible to predict the exercise pacing rate profile with significant accuracy, according to the patient's functional class when ergospirometry apparatus is not available for a cardiopulmonary stress test (CPX). PRPS for Windows is based on the OPR method and some known workload/metabolic cost of exercise relationships during effort. The present study had two aims; first, to evaluate the reliability of PRPS in accurately predicting pacing rate profiles; and second, the suitability of activity and metabolic rate responsive sensors in supplying pacing rates sufficiently near to those predicted using CPX or PRPS. To test the reliability of PRPS we studied 244 patients, NYHA Class I-II, under two different stress test protocols. In one, the bicycle protocol (25 W, 2-minute steps), we tested 137 normal patients (94 men and 43 women, mean age 67 +/- 15 years). Sixty-eight of these were simultaneously CPX tested. PRPS predicted pacing rates were matched against the patients' sinus rhythms or their theoretical CPX measured VO2 heart rates (OPR method). Linear regression analysis was highly significant (r = 0.93 and r = 0.97, respectively). The other, the treadmill protocol, consisted of three different protocols. (1) Speed Incremental Treadmill Stress Test (SITST): 57 patients underwent CPX (33 men and 24 women, mean age 67 +/- 15 years, NYHA Class I-II). All had been pacemaker implanted for SSS and/or advanced atrioventricular block (AVB). PRPS pacing rates were matched against CPX VO2 OPR calculated heart rates (r = 0.93), (linear regression analysis). (2) CAEP: 30 patients underwent CPX (26 men and 4 women, mean age 61 +/- 11 years, NYHA Class I-II). Thirteen of them had been

  1. 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.

  2. 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 (Z(R)) from the high-frequency ripple because of cardiac effect (Z(C)). Impedance minute ventilation is continuously calculated from Z(R) 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.

  3. A hands-on course teaching bioinstrumentation through the design and construction of a benchtop cardiac pacemaker.

    PubMed

    Bouchard, Matthew B; Downs, Matthew E; Jangraw, David C; Kyle, Aaron M

    2013-01-01

    We have developed a bioinstrumentation course that emphasizes practical application of engineering and biological concepts by having students focus on the development of a single biomedical device: a cardiac pacemaker. In creating their benchtop pacemaker, students learn about and design sensing circuitry, data acquisition and processing code, control system algorithms, and stimulation electronics. They also gain an understanding of cardiac anatomy and electrophysiology. The separate elements of the pacemaker created throughout the semester will be repeatedly tested, re-designed, and integrated with one another, culminating in an emulated pacemaker whose efficacy will be tested on North American bullfrogs. It is hypothesized that the hands-on learning in this course, coupled with the practical application of concepts in the context of a single biomedical device, will enhance students' skills in bioinstrumentation design.

  4. 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.

  5. Capsule endoscopy in patients with cardiac pacemakers, implantable cardioverter defibrillators, and left heart devices: a review of the current literature.

    PubMed

    Bandorski, Dirk; Keuchel, Martin; Brück, Martin; Hoeltgen, Reinhard; Wieczorek, Marcus; Jakobs, Ralf

    2011-01-01

    Background and Study Aims. Capsule endoscopy is an established tool for investigation of the small intestine. Because of limited clinical experience in patients with cardiac devices, the Food and Drug Administration and the manufacturer recommended not to use capsule endoscopy in these patients. The vast majority of investigations did not reveal any interference between capsule endoscopy and cardiac devices. Methods. Studies investigating interference between CE and cardiac devices were analysed. For the review we considered studies published in English or German and indexed in Medline, as well as highly relevant abstracts. Results. In vitro and in vivo studies mainly revealed no interference between capsule endoscopy and cardiac devices. Technical data of capsule endoscopy (Given Imaging) reveal that interference with cardiac pacemakers and implantable cardioverter defibrillator is impossible. Telemetry can interfere with CE video. Conclusion. The clinical use of capsule endoscopy (Given Imaging) is unproblematic in patients with cardiac pacemakers.

  6. Rechargeable silver-modified mercuric oxide-zinc cell for cardiac pacemakers.

    PubMed

    Tyers, G F; Hughes, H C; Brownlee, R R; Manley, N J; Gorman, I N

    1976-11-04

    Tests were conducted on rechargeable mercury-zinc pacemaker batteries under simulated and actual biologic conditions, using a variety of discharge rates and charging schedules. In tests on 96 cells at a 6.4 milliampere (ma) discharge, recharging once every 15 months of simulated pacing at a 25 microampere (mua) drain, the earliest cell failure occurred after an equivalent of 50 years of pacing. The mean pacing equivalent for all 96 cells was more than 140 years. In 6.4 ma discharge tests on 24 cells, recharging once every 8 days of simulated pacing, only 1 cell in 24 failed after an equivalent of more than 500 years of pacing (actual time 2 years). In tests on 13 cells pacing at a 200 mua drain without recharging, the simulated mean duration of pacing before total discharge was 4.8 years. Seven other cells at a 200 mua drain with periodic recharging continue to function normally after more than 7 years of actual time, simulating 56 years of pacing at a 25 mua drain. Cardiac pacemakers using the rechargeable mercury-zinc cell have been implanted in animals for more than 2 1/2 years and in patients for more than 1 year with all units continuing to function satisfactorily. It has been demonstrated unequivocally that a rechargeable mercury-zinc pacemaker will function continuously for more than 4 years without recharging and that periodic recharging will extend pacing life far beyond that predicted for lithium and nuclear primary power sources.

  7. Genetically engineered cardiac pacemaker: Stem cells transfected with HCN2 gene and myocytes—A 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.

  8. [The current status of permanent cardiac pacing in Spain. A report of the National Pacemaker Data Bank].

    PubMed

    Coma Samartín, R

    1997-11-01

    We report the activity concerning permanent cardiac pacing in Spain during year 1995, based on data submitted to the National Pacemaker Registry corresponding to the European Pacemaker Card. We describe population, etiology and electrocardiographic alterations that determined the need for stimulation and the global distribution of stimulation modes (AAI 1.7%; DDD 20.2%; VDD 11.3% and VVI 66.8%). We emphasize, among other aspects, stimulation in A-V block cases, in sick-sinus syndrome and tendencies compared to 1994's data and limited data corresponding to 1996.

  9. Inhomogeneity of action potential waveshape assists frequency entrainment of cardiac pacemaker cells.

    PubMed

    Cloherty, S L; Lovell, N H; Celler, B G; Dokos, S

    2001-10-01

    In this paper, we have employed ionic models of sinoatrial node cells to investigate the synchronization of a pair of coupled cardiac pacemaker cells from central and peripheral regions of the sinoatrial node. The free-running cycle length of the cell models was perturbed using two independent techniques and the minimum coupling conductance required to achieve frequency entrainment was used to assess the relative ease with which various cell pairs achieve entrainment. The factors effecting entrainment were further investigated using single-cell models paced with an artificial biphasic coupling current. Our simulation results suggest that dissimilar cell types, those with largely different upstroke velocities entrain more easily, that is, they require less coupling conductance to achieve 1:1 frequency entrainment. We, therefore, propose that regional variation in action-potential waveshape within the sinoatrial node assists frequency synchronization in vivo.

  10. Exercise training starting at weaning age preserves cardiac pacemaker function in adulthood of diet-induced obese rats.

    PubMed

    Carvalho de Lima, Daniel; Guimarães, Juliana Bohnen; Rodovalho, Gisele Vieira; Silveira, Simonton Andrade; Haibara, Andrea Siqueira; Coimbra, Cândido Celso

    2014-08-01

    Peripheral sympathetic overdrive in young obese subjects contributes to further aggravation of insulin resistance, diabetes, and hypertension, thus inducing worsening clinical conditions in adulthood. Exercise training has been considered a strategy to repair obesity autonomic dysfunction, thereby reducing the cardiometabolic risk. Therefore, the aim of this study was to assess the effect of early exercise training, starting immediately after weaning, on cardiac autonomic control in diet-induced obese rats. Male Wistar rats (weaning) were divided into four groups: (i) a control group (n = 6); (ii) an exercise-trained control group (n = 6); (iii) a diet-induced obesity group (n = 6); and (iv) an exercise-trained diet-induced obesity group (n = 6). The development of obesity was induced by 9 weeks of palatable diet intake, and the training program was implemented in a motor-driven treadmill (5 times per week) during the same period. After this period, animals were submitted to vein and artery catheter implantation to assess cardiac autonomic balance by methylatropine (3 mg/kg) and propranolol (4 mg/kg) administration. Exercise training increased running performance in both groups (p < 0.05). Exercise training also prevented the increased resting heart rate in obese rats, which seemed to be related to cardiac pacemaker activity preservation (p < 0.05). Additionally, the training program preserved the pressure and bradycardia responses to autonomic blockade in obese rats (p < 0.05). An exercise program beginning at weaning age prevents cardiovascular dysfunction in obese rats, indicating that exercise training may be used as a nonpharmacological therapeutic strategy for the treatment of cardiometabolic diseases.

  11. Presentation of untreated systemic mastocytosis as recurrent, pulseless-electrical-activity cardiac arrests resistant to cardiac pacemaker.

    PubMed

    Butterfield, Joseph H; Weiler, Catherine R

    2014-01-01

    Recurrent, pulseless-electrical-activity (PEA) cardiac arrests were the novel presentation of untreated systemic mastocytosis in an 85-year-old woman who lacked cutaneous findings of mastocytosis. Despite prior implantation of a dual-chamber cardiac pacemaker 3 weeks previously for similar spells, she experienced a PEA arrest accompanied by flushing, increased urinary N-methylhistamine excretion and serum tryptase values on the day of presentation to our clinic. Bone marrow biopsy findings conducted to rule out breast cancer metastases showed 30% mast cell infiltration, aberrant expression of CD25 and a positive c-kit Asp816Val mutation. Treatment with a combination of H1 and H2 receptor blockers reduced flushing and eliminated hypotension. Maintenance medication included aspirin, cetirizine, ranitidine, montelukast, oral cromolyn sodium and an epinephrine autoinjector (as needed). At 6-month follow-up, the patient remained free of PEA arrests, flushing, or any clinical signs of mastocytosis or mast cell degranulation. PEA cardiac arrests may therefore be a presenting sign of untreated systemic mastocytosis.

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

    PubMed

    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

    2013-04-30

    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 "Ca(2+) clock," where cyclical release of Ca(2+) from Ca(2+) stores depolarizes the membrane during diastole via activation of the Na(+)-Ca(2+) 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 Ca(2+) 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 Ca(2+) 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 Ca(2+)-activated intermediate K(+) conductance (IK(Ca), KCa3.1, or SK4) in young and old stage-derived hESC-CMs. IK(Ca) inhibition produced MDP depolarization and pacemaker suppression. By shaping the MDP driving force and exquisitely balancing inward currents during diastolic depolarization, IK(Ca) appears to play a crucial role in human embryonic cardiac automaticity.

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

    NASA Astrophysics Data System (ADS)

    Elber Duverger, James; Boudreau-Béland, 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. Increased dependency of cardiac pacemaker activity on extracellular Ca after adrenergic blockade in the frog heart.

    PubMed

    Fukuda, Y

    1986-01-01

    The frog sinus venosus shows spontaneous regular pacemaker activity, even in the absence of extracellular Ca2+. When an alpha-adrenergic blocking agent (phentolamine) is applied, the rate of pacemaker activity, height of action potential, rate of slow diastolic depolarization, and the maximum diastolic potential become strongly dependent upon the extracellular Ca2+ concentration.

  19. Telemetry guided pacemaker programming: impact of output amplitude and the use of low threshold leads on projected pacemaker longevity.

    PubMed

    Schwaab, B; Fröhlig, G; Schwerdt, H; Heisel, A; Berg, M; Schieffer, H

    1998-11-01

    In a prospective study, a low threshold screw-in electrode (Medtronic 5078, group I, n = 9) was compared to a conventional active fixation lead (Biotronik Y60BP, group II, n = 9) to investigate whether lower pacing thresholds really translate into longer projected service life of the pacemaker. The leads were implanted in the atrium and were connected to a dual chamber pacing system which included the same ventricular lead (Medtronic 5024) and the same pulse generator model (Intermedics 294-03) in both groups. Eighteen months after implantation, atrial and ventricular pacing thresholds were measured as the charge delivered per pulse [microC] at 0.5, 1.0, 1.5, 2.0, and 3.5 V, respectively. For chronic output programming in both channels, patients capturing at 0.5 V were set to 1.0 V, those capturing at 1.5 V were permanently programmed to 2.0 V with the double of the charge threshold as the safety margin for pacing ("safety charge"). A combination of atrial and ventricular output settings was optimal, if it resulted in minimum battery current drain (microA] as measured by pacemaker telemetry. In both groups, current consumption [microA] decreased significantly as output amplitude was decreased, exhibiting its lowest value at 1.0 V in either channel. All ventricular leads could be programmed to the optimum output amplitude of 1.0 V in groups 1 and 2. As the 2:1 "safety charge" values were almost identical, the ventricular channel essential contributes the same amount to the battery drain of the pacing system in both groups. In the atrium, all patients of group 1 could be programmed to the optimum output amplitude of 1.0 V with an average pulse duration of 0.42 +/- 0.15 ms. In group 2, however, all patients had to be programmed to 2.0 V with a mean pulse width of 0.52 +/- 0.15 ms. With the atrial and ventricular output being optimized, the average battery drain of the whole pacing system was 12.19 +/- 0.63 microA in group 1 versus 14.42 +/- 0.32 microA in group 2 (P

  20. Practical and ethical considerations in the management of pacemaker and implantable cardiac defibrillator devices in terminally ill patients

    PubMed Central

    Sorkness, Christine A.

    2017-01-01

    More than 4.5 million people worldwide live with an implanted pacemaker, including >3 million in the USA alone. Also, >0.8 million people in the USA have an implantable cardioverter defibrillator (ICD). Knowing the principles of managing these devices towards the end of life is important, as the interruption of their function may have serious consequences. This article provides health care providers who are not specialized in cardiac electrophysiology with an introduction to the general principles of management of pacemakers or ICD devices towards the end of life, with a suggested algorithm for approaching this process. Also discussed are pertinent ethical and practical considerations in deciding on and implementing a management strategy for these devices during terminal illnesses.

  1. 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

  2. Medicare’s Policies and Prospective Payment Rates for Cardiac Pacemaker Surgeries need Review and Revision.

    DTIC Science & Technology

    1985-02-26

    pacemaker manufacturers whose sales account for about 80 percent of the pacemaker sales in the United States. The four manufacturers are: -- Cordis ...percentage increase in the hospital market basket (an index designed to measure changes in the prices hospitals pay for goods and services) plus 0.25 percent...For fiscal year 1986, the DRG payment rates cannot be in- creased by more than the estimated change in the hospital market basket plus 0.25 percent

  3. Interference of programmed electromagnetic stimulation with pacemakers and automatic implantable cardioverter defibrillators.

    PubMed

    Gwechenberger, Marianne; Rauscha, Friedrich; Stix, Günter; Schmid, Gernot; Strametz-Juranek, Jeanette

    2006-07-01

    A commercially available magnetic therapy system, designed for clinical application as well as for private use without medical supervision, was examined with respect to its potential for causing electromagnetic interference with implantable pacemakers (PMs) and automatic implantable cardioverter defibrillators (AICDs). A sample of 15 PMs and 5 AICDs were experimentally investigated. Each of the implants was realistically positioned in a homogeneous, electrically passive torso phantom and exposed to the magnetic fields of the system's applicators (whole body mat, cushion, and bar applicator). The detection thresholds of the implants were programmed to maximum sensitivity and both unipolar as well as bipolar electrode configurations were considered. The evaluation of possible interferences was derived from the internal event storages and pacing statistics recorded by the implants during exposure. Any "heart activity" recorded by the implants during exposure was interpreted as a potential interference, because the implant obviously misinterpreted the external interference signal as a physiological signal. Only cases without any recorded "heart activity" and with nominal pacing rates (as expected from the program parameter settings) of the implants were rated as "interference-free." Exposure to the whole body mat (peak magnetic induction up to 265 microT) did not show an influence on PMs and AICD in any case. The cushion applicator at the highest field intensity (peak magnetic induction up to 360 microT) led to atrial sensing defects in four PM models with unipolar electrode configuration. Under bipolar electrode configuration no disturbances occurred. The bar applicator led to sensing problems and consecutively reduced pacing rates in all tested PM models under unipolar electrode configuration and maximum field intensity (peak magnetic induction up to 980 microT). Bipolar electrode configuration resolved the problem. The investigated AICDs did not show malfunctions

  4. A migrating pacemaker.

    PubMed

    Gale, C P; Mulley, G P

    2005-03-01

    A deceased 79 year old man with a permanent cardiac pacemaker was due to be cremated, but the pacemaker generator was not detectable by palpation. A hand held metal detector to locate the device so that it could be extracted before cremation.

  5. 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

    2009-02-07

    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.

  6. Evaluation of Safety and Efficacy of Qinming8631 DR Implantable Cardiac Pacemaker in Chinese Patients: A Prospective, Multicenter, Randomized Controlled Trial of the First Domestically Developed Pacemaker of China

    PubMed Central

    Xiang, Mei-Xiang; Wang, Dong-Qi; Xu, Jing; Zhang, Zheng; Hu, Jian-Xin; Wang, Dong-Mei; Gu, Xiang; Liu, He-Ping; Guo, Tao; Yang, Xiang-Jun; Ling, Feng; Lin, Jia-Feng; Cai, Shang-Lang; Zhu, Guo-Bin; Wang, Jian-An

    2016-01-01

    Background: High cost of imported pacemakers is a main obstacle for Chinese patients suffering from bradyarrhythmia, and a domestically developed pacemaker will help lower the burden. This study aimed to evaluate the safety and efficacy of Qinming8631 DR (Qinming Medical, Baoji, China), the first domestically developed dual-chamber pacemaker of China, compared with a commercially available pacemaker Talos DR (Biotronik, Berlin, Germany) in Chinese patients. Methods: A prospective randomized trial was conducted at 14 centers in China. Participants were randomized into trial (Qinming8631 DR) and control (Talos DR) groups. Parameters of the pacing systems were collected immediately after device implantation and during follow-ups. The effective pacing rate at 6-month follow-up was recorded as the primary end point. Electrical properties, magnet response, single- and double-pole polarity conversion, rate response function, and adverse events of the pacing system were analyzed. The Cochran-Mantel-Haenszel Chi-square test, paired t-test, and Wilcoxon signed-rank test were used for measuring primary qualitative outcomes and comparing normally and abnormally distributed measurement data. Results: A total of 225 patients with a diagnosis of bradyarrhythmia and eligible for this study were randomly enrolled into the trial (n = 113) and control (n = 112) groups. They underwent successful pacemaker implantation with acceptable postoperative pacing threshold and sensitivity. Effective pacing rates of trial and control groups were comparable both in the full analysis set and the per protocol set (81.4% vs. 79.5%, P = 0.712 and 95.4% vs. 89.5%, P = 0.143, respectively). In both data sets, noninferiority of the trial group was above the predefined noninferiority limit (−9.5%). Conclusions: This study established the noninferiority of Qinming8631 DR to Talos DR. The safety and efficacy of Qinming8631 DR pacemaker were comparable to those of Talos DR in treating patients with

  7. SU-E-T-802: Verification of Implanted Cardiac Pacemaker Doses in Intensity-Modulated Radiation Therapy: Dose Prediction Accuracy and Reduction Effect of a Lead Sheet

    SciTech Connect

    Lee, J; Chung, J

    2015-06-15

    Purpose: To verify delivered doses on the implanted cardiac pacemaker, predicted doses with and without dose reduction method were verified using the MOSFET detectors in terms of beam delivery and dose calculation techniques in intensity-modulated radiation therapy (IMRT). Methods: The pacemaker doses for a patient with a tongue cancer were predicted according to the beam delivery methods [step-and-shoot (SS) and sliding window (SW)], intensity levels for dose optimization, and dose calculation algorithms. Dosimetric effects on the pacemaker were calculated three dose engines: pencil-beam convolution (PBC), analytical anisotropic algorithm (AAA), and Acuros-XB. A lead shield of 2 mm thickness was designed for minimizing irradiated doses to the pacemaker. Dose variations affected by the heterogeneous material properties of the pacemaker and effectiveness of the lead shield were predicted by the Acuros-XB. Dose prediction accuracy and the feasibility of the dose reduction strategy were verified based on the measured skin doses right above the pacemaker using mosfet detectors during the radiation treatment. Results: The Acuros-XB showed underestimated skin doses and overestimated doses by the lead-shield effect, even though the lower dose disagreement was observed. It led to improved dose prediction with higher intensity level of dose optimization in IMRT. The dedicated tertiary lead sheet effectively achieved reduction of pacemaker dose up to 60%. Conclusion: The current SS technique could deliver lower scattered doses than recommendation criteria, however, use of the lead sheet contributed to reduce scattered doses.Thin lead plate can be a useful tertiary shielder and it could not acuse malfunction or electrical damage of the implanted pacemaker in IMRT. It is required to estimate more accurate scattered doses of the patient with medical device to design proper dose reduction strategy.

  8. 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.)

  9. 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

  10. Cell-specific Dynamic Clamp analysis of the role of funny If current in cardiac pacemaking.

    PubMed

    Ravagli, E; Bucchi, A; Bartolucci, C; Paina, M; Baruscotti, M; DiFrancesco, D; Severi, S

    2016-01-01

    We used the Dynamic Clamp technique for i) comparative validation of conflicting computational models of the hyperpolarization-activated funny current, If, and ii) quantification of the role of If in mediating autonomic modulation of heart rate. Experimental protocols based on the injection of a real-time recalculated synthetic If current in sinoatrial rabbit cells were developed. Preliminary results of experiments mimicking the autonomic modulation of If demonstrated the need for a customization procedure to compensate for cellular heterogeneity. For this reason, we used a cell-specific approach, scaling the maximal conductance of the injected current based on the cell's spontaneous firing rate. The pacemaking rate, which was significantly reduced after application of Ivabradine, was restored by the injection of synthetic current based on the Severi-DiFrancesco formulation, while the injection of synthetic current based on the Maltsev-Lakatta formulation did not produce any significant variation. A positive virtual shift of the If activation curve, mimicking the Isoprenaline effects, led to a significant increase in pacemaking rate (+17.3 ± 6.7%, p < 0.01), although of lower magnitude than that induced by real Isoprenaline (+45.0 ± 26.1%). Similarly, a negative virtual shift of the activation curve significantly lowered the pacemaking rate (-11.8 ± 1.9%, p < 0.001), as did the application of real Acetylcholine (-20.5 ± 5.1%). The Dynamic Clamp approach, applied to the If study in cardiomyocytes for the first time and rate-adapted to manage intercellular variability, indicated that: i) the quantitative description of the If current in the Severi-DiFrancesco model accurately reproduces the effects of the real current on rabbit sinoatrial cell pacemaking rate and ii) a significant portion (50-60%) of the physiological autonomic rate modulation is due to the shift of the If activation curve.

  11. Measured Effects of Square-Wave Modulated RF Fields (450 and 3100 MHz) on Cardiac Pacemakers

    DTIC Science & Technology

    1974-12-01

    population. Top row; Stimtech 3821; G.E. A2075A; Medcor 3-70A Middle row: Amer. Opt. 281003, and 281143; Biotronik IDP-44 Bottom row; Medtronic...American Optical Model 281143 (Predicta)--N3 effects were observed under all conditions tested. Biotronik Model IDP-44--This model pacemaker cut off at...tests. Three other models (the Biotronik model IDP-44, Cordis model 133C7, and G. E. model A2072D) demon- strated no serious effects at 200 V/m

  12. Safety Profile of Liver FibroScan in Patients with Cardiac Pacemakers or Implantable Cardioverter-Defibrillators

    PubMed Central

    Pranke, Stephanie; Rashidi, Farid; Nosib, Shravan; Worobetz, Lawrence

    2017-01-01

    Background. Emerging evidence suggests that nonalcoholic fatty liver disease (NAFLD) is associated with coronary artery diseases and arrhythmias. The FibroScan (Echosens, France), a widely available, noninvasive device, is able to detect liver fibrosis and steatosis within this patient population. However, the FibroScan is currently contraindicated in patients with cardiac pacemakers (PM) or implantable cardioverter-defibrillators (ICD). Objective. To determine the safety profile of FibroScan testing in patients with PM or ICD. Methods. Consecutive outpatients undergoing routine device interrogations at a tertiary level teaching hospital underwent simultaneous liver stiffness measurements. PM or ICD performance data, device types, patient demographics, medical history, and previous laboratory and conventional liver imaging results were collected. Results. Analysis of 107 subjects with 33 different types of implanted cardiac devices, from 5 different companies (Medtronic, Sorin, ELA Medical, Boston Scientific, and St. Jude), did not demonstrate any adverse events as defined by abnormal device sensing/pacing or ICD firing. This population included high risk subjects undergoing active pacing (n = 53) and with right pectoral PM placement (n = 1). None of the subjects had any clinical signs of decompensated congestive heart failure or cirrhosis during the exam. Conclusion. TE with FibroScan can be safely performed in patients with PM or ICD. PMID:28349045

  13. The missing link in the mystery of normal automaticity of cardiac pacemaker cells.

    PubMed

    Lakatta, Edward G; Vinogradova, Tatiana M; Maltsev, Victor A

    2008-03-01

    Earlier studies of the initiating event of normal automaticity of the heart's pacemaker cells, inspired by classical quantitative membrane theory, focused upon ion currents (IK, I f) that determine the maximum diastolic potential and the early phase of the spontaneous diastolic depolarization (DD). These early DD events are caused by the prior action potential (AP) and essentially reflect a membrane recovery process. Events following the recovery process that ignite APs have not been recognized and remained a mystery until recently. These critical events are linked to rhythmic intracellular signals initiated by Ca2+ clock (i.e., sarcoplasmic reticulum [SR] cycling Ca2+). Sinoatrial cells, regardless of size, exhibit intense ryanodine receptor (RyR), Na+/Ca2+ exchange (NCX)-1, and SR Ca2+ ATPase-2 immunolabeling and dense submembrane NCX/RyR colocalization; Ca2+ clocks generate spontaneous stochastic but roughly periodic local subsarcolemmal Ca2+ releases (LCR). LCRs generate inward currents via NCX that exponentially accelerate the late DD. The timing and amplitude of LCR/I NCX-coupled events control the timing and amplitude of the nonlinear terminal DD and therefore ultimately control the chronotropic state by determining the timing of the I CaL activation that initiates the next AP. LCR period is precisely controlled by the kinetics of SR Ca2+ cycling, which, in turn, are regulated by 1) the status of protein kinase A-dependent phosphorylation of SR Ca2+ cycling proteins; and 2) membrane ion channels ensuring the Ca2+ homeostasis and therefore the Ca2+ available to Ca2+ clock. Thus, the link between early DD and next AP, missed in earlier studies, is ensured by a precisely physiologically regulated Ca2+ clock within pacemaker cells that integrates multiple Ca2+-dependent functions and rhythmically ignites APs during late DD via LCRs-I NCX coupling.

  14. 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.

  15. Cardiac chambers perforation by pacemaker and cardioverter-defibrillator leads. Own experience in diagnosis, treatment and preventive methods.

    PubMed

    Maziarz, Andrzej; Ząbek, Andrzej; Małecka, Barbara; Kutarski, Andrzej; Lelakowski, Jacek

    2012-01-01

    Cardiac chamber perforation is an uncommon, but potentially dangerous, complication of implantation of a pacemaker (PM) or a cardioverter-defibrillator (ICD). Different clinical presentations are related to the time between implantation and perforation, localisation of the perforation and concomitant lesions in neighbouring organs. Diagnosis is based on concomitant analysis of the clinical picture, ECG tracings, PM or ICD function check-up with a programmer, and review of echocardiographic, X-ray and computed tomography pictures. We analysed seven cases of perforation. Perforating leads were removed in all cases and a new pacing system was implanted in five cases. Choice of operative technique (unscrewing and direct traction from device pocket, Cook system or surgical procedure with pericardial drainage) depended on the time elapsing between implantation and perforation, the presence of lesions of other organs, and the amount of fluid in the pericardial sac. Avoiding unsafe localisation of a pacing electrode in the apex and free wall of the right ventricle and in the free anterolateral wall of the right atrium, and avoiding leaving an extra length of pacing lead under tension and overscrewing of the lead helix seem to be the best ways of prevention.

  16. Pacemaker current i(f) in adult canine cardiac ventricular myocytes.

    PubMed Central

    Yu, H; Chang, F; Cohen, I S

    1995-01-01

    1. Single cells enzymatically isolated from canine ventricle and canine Purkinje fibres were studied with the whole-cell patch clamp technique, and the properties of the pacemaker current i(f) compared. 2. Steady-state i(f) activation occurred in canine ventricular myocytes at more negative potentials (-120 to -170 mV) than in canine Purkinje cells (-80 to -130 mV). 3. Reversal potentials were obtained in various extracellular Na+ (140, 79 or 37 mM) and K+ concentrations (25, 9 or 5.4 mM) to determine the ionic selectivity of i(f) in the ventricle. The results suggest that this current was carried by both sodium and potassium ions. 4. The plots of the time constants of i(f) activation against voltage were 'bell shaped' in both canine ventricular and Purkinje myocytes. The curve for the ventricular myocytes was shifted about 30 mV in the negative direction. In both ventricular and Purkinje myocytes, the fully activated I-V relationship exhibited outward rectification in 5.4 mM extracellular K+. 5. Calyculin A (0.5 microM) increased i(f) by shifting its activation to more positive potentials in ventricular myocytes. Protein kinase inhibition by H-7 (200 microM) or H-8 (100 microM) reversed the positive voltage shift of i(f) activation. This effect of calyculin A also occurred when the permeabilized patch was used for whole-cell recording. 6. These results indicate i(f) is present in ventricular myocytes. If shifted to more positive potentials i(f) could play a role in ischaemia-induced ventricular arrhythmias. The negative shift of i(f) in the ventricle might play a role in differentiating non-pacing regions of the heart from those regions that pace. PMID:7545232

  17. 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 ...

  18. Cardiac rehabilitation for a skydiver after aortic valve replacement for pure aortic regurgitation and resection of the ascending aorta complicated by active infective endocarditis and heart block requiring a pacemaker

    PubMed Central

    Solomon, Tonja R.; DeJong, Sandra; Bilbrey, Tim; Carbone, Pasquale; Campbell, Mark; Parker, Robert D.; Lira, Alessandra; Amarante, Diogo; Schussler, Jeffrey M.

    2017-01-01

    A professional skydiver underwent aortic valve and ascending aorta replacement complicated by infective endocarditis with root abscess and pacemaker implantation. He then enrolled in the Baylor Heart and Vascular Hospital cardiac rehabilitation (CR) program as part of its specificity of testing and exercise training facility. He performed specific skydiving cardiovascular and muscular strength tests at the beginning and the end of the CR program. His pacemaker was interrogated to ascertain any arrhythmias or lead displacement over the course of the CR program. Daily exercise training was customized to match the physical demands of skydiving, including two sessions at iFLY Dallas. Upon completion of the daily exercise sessions, the patient performed a simulated free-fall drop test. He then performed a true jump at Dallas Skydive Center and subsequently traveled to Arizona for a skydiving competition, where he performed 35 true jumps with no adverse events or symptoms. This case illustrates how CR, tailored to a patient's specific needs, can aid in the return to rigorous activity.

  19. Cardiac catheterization laboratory imaging quality assurance program.

    PubMed

    Wondrow, M A; Laskey, W K; Hildner, F J; Cusma, J; Holmes, D R

    2001-01-01

    With the recent approval of the National Electrical Manufacturers Association (NEMA) standard for "Characteristics of and Test Procedures for a Phantom to Benchmark Cardiac Fluoroscopic and Photographic Performance," comprehensive cardiac image assurance control programs are now possible. This standard was developed by a joint NEMA/Society for Cardiac Angiography and Interventions (SCA&I) working group of imaging manufacturers and cardiology society professionals over the past 4 years. This article details a cardiac catheterization laboratory image quality assurance and control program that includes the new standard along with current regulatory requirements for cardiac imaging. Because of the recent proliferation of digital imaging equipment, quality assurance for cardiac imaging fluoroscopy and digital imaging are critical. Included are the previous works recommended by the American College of Cardiology (ACC) and American Heart Association (AHA), Society for Cardiac Angiographers and Interventions (SCA&I), and authors of previous image quality subjects.

  20. [Pacemaker, implanted cardiac defibrillator and irradiation: Management proposal in 2010 depending on the type of cardiac stimulator and prognosis and location of cancer].

    PubMed

    Lambert, P; Da Costa, A; Marcy, P-Y; Kreps, S; Angellier, G; Marcié, S; Bondiau, P-Y; Briand-Amoros, C; Thariat, J

    2011-06-01

    Ionizing radiation may interfere with electric components of pacemakers or implantable cardioverter-defibrillators. The type, severity and extent of radiation damage to pacemakers, have previously been shown to depend on the total dose and dose rate. Over 300,000 new cancer cases are treated yearly in France, among which 60% are irradiated in the course of their disease. One among 400 of these patients has an implanted pacemaker or defibrillator. The incidence of pacemaker and implanted cardioverter defribillator increases in an ageing population. The oncologic prognosis must be weighted against the cardiologic prognosis in a multidisciplinary and transversal setting. Innovative irradiation techniques and technological sophistications of pacemakers and implantable cardioverter-defibrillators (with the introduction of more radiosensitive complementary metal-oxide-semiconductors since 1970) have potentially changed the tolerance profiles. This review of the literature studied the geometric, dosimetric and radiobiological characteristics of the radiation beams for high energy photons, stereotactic irradiation, protontherapy. Standardized protocols and radiotherapy optimization (particle, treatment fields, energy) are advisable in order to improve patient management during radiotherapy and prolonged monitoring is necessary following radiation therapy. The dose received at the pacemaker/heart should be calculated. The threshold for the cumulated dose to the pacemaker/implantable cardioverter-defibrillator (2 to 5 Gy depending on the brand), the necessity to remove/displace the device based on the dose-volume histogram on dosimetry, as well as the use of lead shielding and magnet are discussed.

  1. Force and torque effects of a 1.5-Tesla MRI scanner on cardiac pacemakers and ICDs.

    PubMed

    Luechinger, R; Duru, F; Scheidegger, M B; Boesiger, P; Candinas, R

    2001-02-01

    Magnetic resonance imaging (MRI) is a widely accepted tool for the diagnosis of a variety of disease states. However, the presence of an implanted pacemaker is considered to be a strict contraindication to MRI in a vast majority of centers due to safety concerns. In phantom studies, the authors investigated the force and torque effects of the static magnetic field of MRI on pacemakers and ICDs. Thirty-one pacemakers (15 dual chamber and 16 single chamber units) from eight manufacturers and 13 ICDs from four manufacturers were exposed to the static magnetic field of a 1.5-Tesla MRI scanner. Magnetic force and acceleration measurements were obtained quantitatively, and torque measurements were made qualitatively. For pacemakers, the measured magnetic force was in the range of 0.05-3.60 N. Pacemakers released after 1995 had low magnetic force values as compared to the older devices. For these devices, the measured acceleration was even lower than the gravity of the earth (< 9.81 N/kg). Likewise, the torque levels were significantly reduced in newer generation pacemakers (< or = 2 from a scale of 6). ICD devices, except for one recent model, showed higher force (1.03-5.85 N), acceleration 9.5-34.2 N/kg), and torque (5-6 out of 6) levels. In conclusion, modern pacemakers present no safety risk with respect to magnetic force and torque induced by the static magnetic field of a 1.5-Tesla MRI scanner. However, ICD devices, despite considerable reduction in size and weight, may still pose problems due to strong magnetic force and torque.

  2. 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

  3. Effect of Surgical Atrial Fibrillation Ablation at the Time of Cardiac Surgery on Risk of Postoperative Pacemaker Implantation.

    PubMed

    El-Chami, Mikhael F; Binongo, José Nilo G; Levy, Mathew; Merchant, Faisal M; Halkos, Michael; Thourani, Vinod; Lattouf, Omar; Guyton, Robert; Puskas, John; Leon, Angel R

    2015-07-01

    The aim of this study was to retrospectively investigate whether performing surgical atrial fibrillation (AF) ablation in conjunction with cardiac surgery (CS) increases the risk for postoperative permanent pacemaker (PPM) requirement. The 30-day risk for PPM requirement was analyzed in consecutive patients who underwent CS from January 2007 to August 27, 2013. Patients were divided into 3 groups: (1) those who underwent AF ablation concomitant with CS (AF ABL), (2) patients with any history of AF who underwent surgery who did not undergo ablation (AF NO ABL), and (3) those with no histories of AF who underwent surgery (NO AF). Logistic regression analysis was performed adjusting for age, gender, and surgery type. Of 13,453 CS patients, 353 (3%) were in the AF ABL group, 1,701 (12%) in the AF NO ABL group, and 11,399 (85%) in the NO AF group. A total of 7,651 patients (57%) underwent coronary artery bypass grafting, 4,384 (33%) underwent valve surgery, and 1,418 (10%) underwent coronary artery bypass grafting and valve surgery. The overall PPM risk was 1.6% (212 of 13,453); risk was 5.7% (20 of 353) in the AF ABL group, 3.1% (53 of 1,701) in the AF NO ABL group, and 1.2% (139 of 11,399) in the NO AF group. The unadjusted and adjusted odds of PPM were higher in the AF ABL and AF NO ABL groups than in the NO AF group (adjusted odds ratio [OR] 2.7, 95% confidence interval [CI] 1.7 to 4.4, and adjusted OR 1.7, 95% CI 1.2 to 2.4, respectively). The unadjusted OR comparing the AF ABL group and the AF NO ABL group was significant (unadjusted OR 1.9, 95% CI 1.9 to 3.2); however, the OR adjusted for surgery type, age, and gender showed a trend toward significance (adjusted OR 1.6, 95% CI 0.9 to 2.7). In conclusion, in this large cohort of patients who underwent CS, surgical AF ablation appeared to carry an increased risk for postoperative PPM implantation.

  4. Preliminary clinical experience with a new radioisotope-powered cardiac pacemaker.

    PubMed

    Smyth, N P; Magovern, G J; Cushing, W J; Keshishian, J M; Kelly, L C; Dixon, M

    1976-02-01

    A small light-weight nuclear-powered pacer has been developed. The pulse generator weight 61 Gm. and occupies a volume of 33 sq. cm. It is a standard R-wave inhibited (VVI) demand pulse generator. The unit has met all United States and foreign atomic energy commission safety specifications including mechanical shock, industrial fire, accidental crush, cremation, impact, and corrosion. Its calculated life is in excess of 20 years. The unit has been shown to be insensitive to electromagnetic interference (EMI) over a wide range of commonly encountered sources of interference. An extensive dog testing program has been carried out and is continuing. The United States Atomic Energy Commission (AEC) has issued a license to conduct clinical trials. These began in October, 1974, and a total of 30 units of 30 units have been implanted so far. An equal number of chemical battery-powered pulse generators has been implanted in a control series of 30 patients. Preliminary results have been gratifying.

  5. 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

  6. Persistence of left supracardinal vein in an adult patient with heart-hand syndrome and cardiac pacemaker.

    PubMed

    Nemec, Jan; Heifetz, Steven

    2008-01-01

    A patient with a sporadic heart-hand syndrome, which includes thumb hypoplasia, septum primum atrial septal defect, and cleft mitral valve is described. During attempted placement of a pacemaker lead, persistence of left superior and inferior vena cava was found in addition to the right-sided caval veins. This corresponds to persistence of left-sided supracardinal vein present during fetal development.

  7. Effects of muscle potential depression and muscle stimulation caused by different insulation coating configurations on cardiac pacemakers.

    PubMed

    Yajima, Toshimi; Yamada, Kenichi; Okubo, Naoko; Nitta, Takashi; Ochi, Masami; Shimizu, Kazuo

    2005-01-01

    Insulation coating was added to the external pacemaker surface to prevent unnecessary electric current leakage to the periphery because the pulse generator body is used as an anode in unipolar pacing. However, a model without insulation coating has recently been used, so we studied the effects on muscle potential inhibition and muscle stimulation of pacemakers in unipolar pacing with different parts of the pacemaker body coated with insulation. Case comparisons were made for the following models: insulated except for the center of one side (33, group C), insulated except for the peripheral zone (10, group E), and noncoated models (11, group N). The muscle detection threshold voltage, muscle detection threshold pulse duration, muscle potential sensing threshold (MP), and lead resistance were measured. A comparison was made of the amount of energy (En) needed to reach the muscle stimulation threshold. For MP values, there was no significant statistical difference between group C and E, whereas a significant difference was present between group C and N and between group E and N. For En values, there was a significant difference between group C and E and between group C and N, but there was no significant difference between group E and N. The muscle potential sensing threshold dose not have a change in group E and much muscle stimulation energy is needed. The muscle potential sensing threshold was low in group N, requiring much muscle stimulation energy. Based on these results, it is usually not necessary to coat the pacemaker with insulation for unipolar pacing.

  8. 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

  9. Heart pacemaker

    MedlinePlus

    ... PA: Elsevier Saunders; 2015:chap 37. Swerdlow CD, Wang PJ, Zipes DP. Pacemakers and implantable cardioverter-defibrillators. ... and lifestyle Controlling your high blood pressure Dietary fats explained Fast food tips Heart attack - discharge Heart ...

  10. Biofilm on artificial pacemaker: fiction or reality?

    PubMed

    Santos, Ana Paula Azevedo; Watanabe, Evandro; Andrade, Denise de

    2011-11-01

    Cardiac pacing through cardiac pacemaker is one of the most promising alternatives in the treatment of arrhythmias, but it can cause reactions natural or complex reactions, either early or late. This study aimed to describe the scientific evidence on the risk of infection and biofilm formation associated with cardiac pacemaker. This is a study of integrative literature review. It included 14 publications classified into three thematic categories: diagnosis (microbiological and/or clinical), complications and therapy of infections. Staphylococcus epidermidis and Staphylococcus aureus were the microorganisms most frequently isolated. It was not possible to determine the incidence of infection associated with pacemakers, since the studies were generally of prevalence. In terms of therapy, the complete removal of pacemakers stood out, especially in cases of suspected biofilm. Still controversial is the use of systemic antibiotic prophylaxis in reducing the incidence of infection associated with implantation of a pacemaker.

  11. Legal Aspects of Cardiac Rehabilitation Exercise Programs.

    ERIC Educational Resources Information Center

    Herbert, William; Herbert, David L.

    1988-01-01

    A medical model is used to examine liability issues related to cardiac rehabilitation programs. Obtaining effective informed consent from patients, standardizing policies and procedures, and exercise prescription and monitoring are among the proposed elements of a risk management model for developing safe and legally defensible programs. (IAH)

  12. 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.

  13. The behavior of dual-chamber pacemakers exposed to a conducted low-frequency disruptive signal.

    PubMed

    Babouri, A; Hedjiedj, A; Guendouz, L; Andretzko, J P

    2006-08-01

    This paper presents a study of the behavior of dual-chamber cardiac pacemakers submitted to low-frequency conducted disruptions. The disruptive signal is sinusoidal, operating at 50 Hz, 60 Hz, 10 kHz and 25 kHz. The behavior of the pacemakers is described by statistical data obtained with a telemetry system and by visualization of the pacemaker signal during the application of the interfering signal. The pacemakers were tested in two configurations. The first one consists of direct application of the interfering signal between the pacemaker terminals. In the second, these attempts are completed by in vitro tests using an electromagnetic model which allow us to take into account the interface which constitutes the human body. The pacemaker under test is inserted into a gelatine phantom mimicking the electrical conductivity of tissues. This study allowed us to define the pacemaker detection thresholds for the two test configurations. For the in vitro approach, which constitutes a complementary approach to a realistic implantation situation, oversensing is noticed for 10 kHz and 25 kHz interfering signal frequencies. Detection thresholds vary from a few tens to a few hundreds of mV, depending on the interfering signal frequency, the device and its programmed detection sensitivities.

  14. Cremation of Leadless Pacemaker.

    PubMed

    Cheung, Lily; Chan, Gary C P; Chan, Joseph Y S; Lau, Chu-Pak

    2017-03-11

    Cremation of implanted cardiac electronic devices can be associated with explosion from rapid gas formation causing potential hazard to the crematoria staffs and facilities. We present four patients who had undergone cremation with a leadless pacemaker (Micra(TM) , Medtronic Inc., MN) left inside their bodies. There was neither reported explosion nor damage to the cremation chamber during the cremation process. In this small series, cremation of Micra(TM) is not associated with noticeable explosion. This article is protected by copyright. All rights reserved.

  15. Inadvertent transarterial pacemaker lead placement.

    PubMed

    Bajaj, Ravi R; Fam, Neil; Singh, Sheldon M

    2015-01-01

    We present a case of a 73-year-old patient with acute left-sided hemiparesis four months after right ventricular pacemaker insertion. Post-procedural electrocardiogram revealed a paced RBBB complex and an abnormal lead path on chest X-ray. Subsequent echocardiography and computed tomography showed left ventricular pacemaker malposition with retrograde passage to the punctured subclavian artery. We also discuss the utility of routine cardiac investigations post-insertion to identify signal lead malposition as well as management strategies once identified.

  16. 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.

  17. Prenatal programming: adverse cardiac programming by gestational testosterone excess

    PubMed Central

    Vyas, Arpita K.; Hoang, Vanessa; Padmanabhan, Vasantha; Gilbreath, Ebony; Mietelka, Kristy A.

    2016-01-01

    Adverse events during the prenatal and early postnatal period of life are associated with development of cardiovascular disease in adulthood. Prenatal exposure to excess testosterone (T) in sheep induces adverse reproductive and metabolic programming leading to polycystic ovarian syndrome, insulin resistance and hypertension in the female offspring. We hypothesized that prenatal T excess disrupts insulin signaling in the cardiac left ventricle leading to adverse cardiac programming. Left ventricular tissues were obtained from 2-year-old female sheep treated prenatally with T or oil (control) from days 30–90 of gestation. Molecular markers of insulin signaling and cardiac hypertrophy were analyzed. Prenatal T excess increased the gene expression of molecular markers involved in insulin signaling and those associated with cardiac hypertrophy and stress including insulin receptor substrate-1 (IRS-1), phosphatidyl inositol-3 kinase (PI3K), Mammalian target of rapamycin complex 1 (mTORC1), nuclear factor of activated T cells –c3 (NFATc3), and brain natriuretic peptide (BNP) compared to controls. Furthermore, prenatal T excess increased the phosphorylation of PI3K, AKT and mTOR. Myocardial disarray (multifocal) and increase in cardiomyocyte diameter was evident on histological investigation in T-treated females. These findings support adverse left ventricular remodeling by prenatal T excess. PMID:27328820

  18. 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... External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker pulse generators is a device that can be programmed to produce one or more pulses at...

  19. 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... External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker pulse generators is a device that can be programmed to produce one or more pulses at...

  20. 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... External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker pulse generators is a device that can be programmed to produce one or more pulses at...

  1. 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... External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker pulse generators is a device that can be programmed to produce one or more pulses at...

  2. 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... External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker pulse generators is a device that can be programmed to produce one or more pulses at...

  3. Patch-clamp analysis in canine cardiac Purkinje cells of a novel sodium component in the pacemaker range.

    PubMed

    Rota, Marcello; Vassalle, Mario

    2003-04-01

    A putative Na+ component playing a role in the initiation and maintenance of spontaneous discharge in Purkinje fibres was studied by means of the whole-cell patch-clamp technique in canine cardiac single Purkinje cells. In 4 mM [K+]o, during depolarising clamp steps, a slowly inactivating current appeared at approximately -58 mV, negative to the threshold for the fast Na+ current (INa; approximately -50 mV). During depolarising ramps, the current underwent inward rectification with a negative slope region that began at approximately -60 mV. The current underlying the negative slope increased during faster ramps, decreased as a function of time when the initial depolarising ramp was over, decreased during depolarisations positive to approximately -35 mV and was much larger than the current during the symmetrical repolarising ramp. Increasing biphasic ('oscillatory') voltage ramps required much smaller currents at a holding potential (Vh) of -60 mV than at -80 mV and were associated with a marked decrease in slope conductance. At Vh -50/-40 mV, the oscillatory ramp currents and superimposed pulse currents reversed direction. The negative slope in the I-V relation as well as the change in current direction at -50/-40 mV were markedly reduced by tetrodotoxin (15 microM) and lidocaine (lignocaine, 100 microM) and therefore are due to a slowly inactivating Na+ current, labelled here INa3. Lower [K+]o (2.7 mM) reduced the steady state slope conductance as well as the current in the diastolic range, and increased as well as shifted INa3 in a negative direction. High [K+]o had the opposite effects. Cs+ (2 mM) and Ba2+ (2 mM) reduced the initial current during depolarising ramps but not INa3. In current-clamp mode, current-induced voltage oscillations elicited action potentials through a gradual transition between diastolic depolarisation and upstroke, consistent with the activation of INa3. Thus, the initiation and maintenance of spontaneous discharge in Purkinje strands

  4. Heart pacemaker - discharge

    MedlinePlus

    ... please enable JavaScript. A pacemaker is a small, battery-operated device that senses when your heart is ... pacemaker is placed under your skin. These include: Battery powered cordless tools (such as screwdrivers and drills) ...

  5. Designing a Computer-Assisted Clinic to Cope with the Evolution of Pacemaker Technology

    PubMed Central

    Pfeil, Catherine N.; Keltz, Paul D.; Gertz, Edward W.; Okawachi, Melanie H.

    1983-01-01

    A computer-assisted program for follow-up monitoring of implanted cardiac pacemakers has been in operation at the San Francisco Veterans Administration Medical Center since 1977. It was originally created at a time when the technology of pacemakers was stable and only a few parameters could be measured or telemetered. Two recent developments have necessitated a major reassessment of this project as a well as redesign of the entire computer infrastructure: the advent of multi-programmable and multi-chamber pacemakers (presenting a wide variety of selectable and interacting parameters and features) and the expansion of the program to follow 4000 patients. In addressing the above two problems we have embarked on a project which involves distributed data structures, interactive multi-tasking and non-deterministic data structures. The resultant computer-based system will allow for maximum flexibility in the definition of data for differing pacemakers while permitting coherent and meaningful studies to be performed across large patient populations.

  6. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) Body mass index. (iv) Systolic blood pressure. (v) Diastolic blood pressure. (vi) The need for cholesterol, blood pressure, and diabetes medications. (3) A list of approved intensive cardiac rehabilitation... prescribed exercise, cardiac risk factor modification, psychosocial assessment, and outcomes...

  7. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) Body mass index. (iv) Systolic blood pressure. (v) Diastolic blood pressure. (vi) The need for cholesterol, blood pressure, and diabetes medications. (3) A list of approved intensive cardiac rehabilitation... prescribed exercise, cardiac risk factor modification, psychosocial assessment, and outcomes...

  8. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) Body mass index. (iv) Systolic blood pressure. (v) Diastolic blood pressure. (vi) The need for cholesterol, blood pressure, and diabetes medications. (3) A list of approved intensive cardiac rehabilitation... prescribed exercise, cardiac risk factor modification, psychosocial assessment, and outcomes...

  9. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... heart-lung transplant. (vii) For cardiac rehabilitation only, other cardiac conditions as specified...) Body mass index. (iv) Systolic blood pressure. (v) Diastolic blood pressure. (vi) The need for cholesterol, blood pressure, and diabetes medications. (3) A list of approved intensive cardiac...

  10. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... heart-lung transplant. (vii) For cardiac rehabilitation only, other cardiac conditions as specified...) Body mass index. (iv) Systolic blood pressure. (v) Diastolic blood pressure. (vi) The need for cholesterol, blood pressure, and diabetes medications. (3) A list of approved intensive cardiac...

  11. ''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.

  12. Increased adherence to cardiac standards of care during participation in cardiac disease management programs.

    PubMed

    Coberley, Carter; Morrow, Greg; McGinnis, Matthew; Wells, Aaron; Coberley, Sadie; Orr, Patty; Shurney, Dexter

    2008-04-01

    Adherence to cardiovascular disease standards of care is critically important for minimizing the risk of mortality and morbidity for individuals with coronary heart disease (CHD) and heart failure (HF). The purpose of this study was to assess the ability of cardiac disease management (DM) programs to assist members with their adherence to evidence-based medicine for cardiovascular diseases. A total of 20,202 members with CHD and/or HF were evaluated 12 months prior to the start of DM programs and during their first 12 months of participation in the programs. Members were assessed for their adherence to appropriate cardiac medications. In addition, low-density lipoprotein (LDL) testing rates and clinical control of LDL values (defined as <100 mg/dL) were measured. The association between LDL control and use of lipid-lowering statins also was assessed. During participation in the cardiac programs, members achieved significant improvement in their adherence to angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and beta-blockers (P < 0.0001). The cardiac population also achieved a significant increase in LDL testing rates and statin use (P < 0.0001). More members attained appropriate LDL control in year 1 compared to baseline (36% relative increase), and this improvement was associated with a 40% relative increase in statin use. In summary, participation in these cardiac DM programs assisted members to improve their adherence to cardiac medications and standards of care guidelines. Such improvements in cardiovascular disease care are likely associated with improved quality of life and reduced risk for mortality.

  13. Combined Standby Transvenous Defibrillator and Demand Pacemaker.

    DTIC Science & Technology

    1975-12-01

    AD-A097 441 CARDIAC CARE SYSTEMS INC RED BANK NJ F/B 6/5 COM13INED STANDBY TRANSVENOJS DEFIBRILLATOR AND DEMAND PACEMAKER--ETC(U) DEC 75 L RUBIN...Development Command Fort Detrick, Frederick, MD 21701 Contract Number DAMD17-74-C-4108. Cardiac Care Systems, Inc. 80 E. Front Street Red Bank , NJ...8217 Cardiac Care Systems, Inc. 4I 80 E. Front Street 61 3121A1j0.4 Red Bank , NJ 07701 a .0_ e- /i\\ - -__________ I1. CONTROLLING OFFICE NAME AND ADDRESS 1.)42

  14. What Is a Pacemaker?

    MedlinePlus

    ... your pacemaker. • If you work around industrial microwaves, electricity, cars or other large motors, ask your doctor about possible effects. Can I use a cell phone or microwave oven if I have a pacemaker? Microwave ovens, electric blankets, remote controls for TV and other common ...

  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.

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

    PubMed Central

    Vedantham, Vasanth

    2015-01-01

    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 are composed of 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. This review discusses these approaches in the context of SAN biology and addresses the potential for clinical translation. PMID:26611337

  17. Inpatient cardiac rehabilitation programs' exercise therapy for patients undergoing cardiac surgery: National Korean Questionnaire Survey.

    PubMed

    Seo, Yong Gon; Jang, Mi Ja; Park, Won Hah; Hong, Kyung Pyo; Sung, Jidong

    2017-02-01

    Inpatient cardiac rehabilitation (ICR) has been commonly conducted after cardiac surgery in many countries, and has been reported a lots of results. However, until now, there is inadequacy of data on the status of ICR in Korea. This study described the current status of exercise therapy in ICR that is performed after cardiac surgery in Korean hospitals. Questionnaires modified by previous studies were sent to the departments of thoracic surgery of 10 hospitals in Korea. Nine replies (response rate 90%) were received. Eight nurses and one physiotherapist completed the questionnaire. Most of the education on wards after cardiac surgery was conducted by nurses. On postoperative day 1, four sites performed sitting on the edge of bed, sit to stand, up to chair, and walking in the ward. Only one site performed that exercise on postoperative day 2. One activity (stairs up and down) was performed on different days at only two sites. Patients received education preoperatively and predischarge for preventing complications and reducing muscle weakness through physical inactivity. The results of the study demonstrate that there are small variations in the general care provided by nurses after cardiac surgery. Based on the results of this research, we recommended that exercise therapy programs have to conduct by exercise specialists like exercise physiologists or physiotherapists for patients in hospitalization period.

  18. Thrombus on pacemaker lead.

    PubMed

    Raut, Monish S; Maheshwari, Arun; Dubey, Sumir

    2015-12-01

    A 58-year-old male was admitted with history of shortness of breath and recurrent fever since two months. He had undergone permanent pacemaker implantation six years back for complete heart block. The patient was persistently having thrombocytopenia. Echocardiographic examination revealed mass (size 4.28 cm(2)) attached to pacemaker lead in right atrium. The patient was scheduled for open-heart surgery for removal of right atrial mass. During surgery, pacemaker leads and pulse generator were also removed along with mass considering the possible source of infection.

  19. 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

  20. 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.

  1. Case report: use caution when applying magnets to pacemakers or defibrillators for surgery.

    PubMed

    Schulman, Peter M; Rozner, Marc A

    2013-08-01

    The application of a magnet to a pacemaker (intended to cause asynchronous pacing) or implanted cardioverter defibrillator (intended to prevent shocks) during surgery without a clear understanding of actual magnet function(s) or precautions can have unexpected, untoward, or harmful consequences. In this report, we present 3 cases in which inadequate assessment of cardiac implanted electronic device (CIED) function, coupled with magnet application, contributed to or resulted in inappropriate antitachycardia pacing or shocks, CIED damage, or patient injury. Although these cases might be rare, they reinforce the need for a timely, detailed preoperative review of CIED function and programming as recommended by the American Society of Anesthesiologists and the Heart Rhythm Society.

  2. Reentry and Ectopic Pacemakers Emerge in a Three-Dimensional Model for a Slab of Cardiac Tissue with Diffuse Microfibrosis near the Percolation Threshold

    PubMed Central

    dos Santos, Rodrigo Weber; Bär, Markus

    2016-01-01

    Arrhythmias in cardiac tissue are generally associated with irregular electrical wave propagation in the heart. Cardiac tissue is formed by a discrete cell network, which is often heterogeneous. Recently, it was shown in simulations of two-dimensional (2D) discrete models of cardiac tissue that a wave crossing a fibrotic, heterogeneous region may produce reentry and transient or persistent ectopic activity provided the fraction of conducting connections is just above the percolation threshold. Here, we investigate the occurrence of these phenomena in three-dimensions by simulations of a discrete model representing a thin slab of cardiac tissue. This is motivated (i) by the necessity to study the relevance and properties of the percolation-related mechanism for the emergence of microreentries in three dimensions and (ii) by the fact that atrial tissue is quite thin in comparison with ventricular tissue. Here, we simplify the model by neglecting details of tissue anatomy, e. g. geometries of atria or ventricles and the anisotropy in the conductivity. Hence, our modeling study is confined to the investigation of the effect of the tissue thickness as well as to the comparison of the dynamics of electrical excitation in a 2D layer with the one in a 3D slab. Our results indicate a strong and non-trivial effect of the thickness even for thin tissue slabs on the probability of microreentries and ectopic beat generation. The strong correlation of the occurrence of microreentry with the percolation threshold reported earlier in 2D layers persists in 3D slabs. Finally, a qualitative agreement of 3D simulated electrograms in the fibrotic region with the experimentally observed complex fractional atrial electrograms (CFAE) as well as strong difference between simulated electrograms in 2D and 3D were found for the cases where reentry and ectopic activity were triggered by the micro-fibrotic region. PMID:27875591

  3. Reentry and Ectopic Pacemakers Emerge in a Three-Dimensional Model for a Slab of Cardiac Tissue with Diffuse Microfibrosis near the Percolation Threshold.

    PubMed

    Alonso, Sergio; Dos Santos, Rodrigo Weber; Bär, Markus

    2016-01-01

    Arrhythmias in cardiac tissue are generally associated with irregular electrical wave propagation in the heart. Cardiac tissue is formed by a discrete cell network, which is often heterogeneous. Recently, it was shown in simulations of two-dimensional (2D) discrete models of cardiac tissue that a wave crossing a fibrotic, heterogeneous region may produce reentry and transient or persistent ectopic activity provided the fraction of conducting connections is just above the percolation threshold. Here, we investigate the occurrence of these phenomena in three-dimensions by simulations of a discrete model representing a thin slab of cardiac tissue. This is motivated (i) by the necessity to study the relevance and properties of the percolation-related mechanism for the emergence of microreentries in three dimensions and (ii) by the fact that atrial tissue is quite thin in comparison with ventricular tissue. Here, we simplify the model by neglecting details of tissue anatomy, e. g. geometries of atria or ventricles and the anisotropy in the conductivity. Hence, our modeling study is confined to the investigation of the effect of the tissue thickness as well as to the comparison of the dynamics of electrical excitation in a 2D layer with the one in a 3D slab. Our results indicate a strong and non-trivial effect of the thickness even for thin tissue slabs on the probability of microreentries and ectopic beat generation. The strong correlation of the occurrence of microreentry with the percolation threshold reported earlier in 2D layers persists in 3D slabs. Finally, a qualitative agreement of 3D simulated electrograms in the fibrotic region with the experimentally observed complex fractional atrial electrograms (CFAE) as well as strong difference between simulated electrograms in 2D and 3D were found for the cases where reentry and ectopic activity were triggered by the micro-fibrotic region.

  4. [Cardiac manifestations of mitochondrial diseases].

    PubMed

    Ritzenthaler, Thomas; Luis, David; Hullin, Thomas; Fayssoil, Abdallah

    2015-05-01

    Mitochondrial diseases are multi-system disorders in relation with mitochondrial DNA and/or nuclear DNA abnormalities. Clinical pictures are heterogeneous, involving endocrine, cardiac, neurologic or sensory systems. Cardiac involvements are morphological and electrical disturbances. Prognosis is worsened in case of cardiac impairment. Treatments are related to the type of cardiac dysfunction including medication or pacemaker implantation.

  5. Pacemaker lead malposition in the left atrial roof is masked by normal pacing thresholds

    PubMed Central

    2014-01-01

    Pacemaker lead malpositioning with subsequent cardiac tamponade is a rare, but serious adverse event. We herein report a case of pacemaker lead malpositioning in a 76-year old female caucasian patient. The lead was malpositioned into the roof of the left atrium after perforation of the superior vena cava, resulting in cardiac tamponade. After fast surgical revision and an uneventful post-operative period, the patient was discharged in excellent condition. PMID:24650143

  6. 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.

  7. 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 ...

  8. 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

  9. Pacemaker Use Following Heart Transplantation

    PubMed Central

    Mallidi, Hari R.; Bates, Michael

    2017-01-01

    Background: The incidence of permanent pacemaker implantation after orthotopic heart transplantation has been reported to be 2%-24%. Transplanted hearts usually exhibit sinus rhythm in the operating room following reperfusion, and most patients do not exhibit significant arrhythmias during the postoperative period. However, among the patients who do exhibit abnormalities, pacemakers may be implanted for early sinus node dysfunction but are rarely used after 6 months. Permanent pacing is often required for atrioventricular block. A different cohort of transplant patients presents later with bradycardia requiring pacemaker implantation, reported to occur in approximately 1.5% of patients. The objectives of this study were to investigate the indications for pacemaker implantation, compare the need for pacemakers following bicaval vs biatrial anastomosis, and examine the long-term outcomes of heart transplant patients who received pacemakers. Methods: For this retrospective, case-cohort, single-institution study, patients were identified from clinical research and administrative transplant databases. Information was supplemented with review of the medical records. Standard statistical techniques were used, with chi-square testing for categorical variables and the 2-tailed t test for continuous variables. Survival was compared with the use of log-rank methods. Results: Between January 1968 and February 2008, 1,450 heart transplants were performed at Stanford University. Eighty-four patients (5.8%) were identified as having had a pacemaker implanted. Of these patients, 65.5% (55) had the device implanted within 30 days of transplantation, and 34.5% (29) had late implantation. The mean survival of patients who had an early pacemaker implant was 6.4 years compared to 7.7 years for those with a late pacemaker implant (P<0.05). Sinus node dysfunction and heart block were the most common indications for pacemaker implantation. Starting in 1997, a bicaval technique was used

  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.

  11. [Analysis of intracardial electrograms in pacemakers and ICD systems by Biotronik].

    PubMed

    Wetzel, U; Piorkowski, C; Richter, S; Müssigbrodt, A; Kucher, A; Hindricks, G

    2010-03-01

    Detailed analysis of stored electrograms is essential for the interpretation of arrhythmias, programming changes, and optimization of the medical therapy in patients with implanted pacemakers and defibrillators. The physician who cares for patients with implantable electrical devices has to be able to understand the detection and treatment algorithms of those devices. Biotronik pacemakers of newer generations are capable of storing intracardiac electrograms. Earlier devices store up to 12 electrograms of 10 s duration after certain trigger events, like atrial tachycardia or high ventricular rates. Cardiac resynchronization systems can store electrograms after patient activation with magnets in addition to the above mentioned trigger-activated electrograms. Defibrillators store intracardiac electrograms during tachycardia episodes with near-field and far-field electrograms of the right ventricular lead in addition to the markers in single and dual chamber defibrillators (in addition to an atrial electrogram) and near field electrograms of the atrial, the right, and the left ventricular electrode in addition to the markers in resynchronization systems. Each channel has a maximum storing capacity of 32 min. If there are more episodes than storing capacity, electrograms of older episodes will be overwritten, but if the newer episodes are all classified as supraventricular, the last two ventricular episodes (VT or VF) will remain in the episode memory. This article describes stored electrograms, detection, and treatment algorithms of implantable cardiac devices manufactured by Biotronik.

  12. Pacemaker follow-up and adequacy of Medicare guidelines.

    PubMed

    Vallario, L E; Leman, R B; Gillette, P C; Kratz, J M

    1988-07-01

    The time of occurrence of cardiac pacemaker problems after implantation was identified to assess the adequacy of published federal guidelines for clinic and transtelephonic follow-up. One hundred eighty-nine pacemaker patients' charts were examined retrospectively to identify pacemaker problems: inadequate sensing, non-capture, battery failure, myoinhibition, muscle stimulation, and inadequate threshold safety margin. Twenty-nine patients (15%) were identified as having pacemaker problems. A total of 41 problems were identified, of which 28 (68%) were corrected by reprogramming. Sixty-one percent of the problems were found during a clinic visit. Problems occurred more frequently during the first year in dual-chamber devices (62%) vs single-chamber devices (35%). During years 1 to 4, when few problems are expected, 30% of all problems of single-chamber devices occurred and 39% of all problems of dual-chamber devices occurred. This is a period of time that Medicare guidelines allow for one clinic visit per year for single- and two visits per year for dual-chamber devices. These data suggest: (1) Many pacemaker problems will be missed with transtelephonic follow-up alone. (2) The majority of problems involving dual-chamber devices occurred in the first year. (3) For both dual- and single-chamber devices, an unexpected significant percentage of problems occurred in 1 to 4 years. (4) Medicare guidelines may be inadequate for follow-up during this time period.

  13. Smartphone-Based Cardiac Rehabilitation Program: Feasibility Study

    PubMed Central

    Chung, Heewon; Yoon, Kwon-Ha; Lee, Jinseok

    2016-01-01

    We introduce a cardiac rehabilitation program (CRP) that utilizes only a smartphone, with no external devices. As an efficient guide for cardiac rehabilitation exercise, we developed an application to automatically indicate the exercise intensity by comparing the estimated heart rate (HR) with the target heart rate zone (THZ). The HR is estimated using video images of a fingertip taken by the smartphone’s built-in camera. The introduced CRP app includes pre-exercise, exercise with intensity guidance, and post-exercise. In the pre-exercise period, information such as THZ, exercise type, exercise stage order, and duration of each stage are set up. In the exercise with intensity guidance, the app estimates HR from the pulse obtained using the smartphone’s built-in camera and compares the estimated HR with the THZ. Based on this comparison, the app adjusts the exercise intensity to shift the patient’s HR to the THZ during exercise. In the post-exercise period, the app manages the ratio of the estimated HR to the THZ and provides a questionnaire on factors such as chest pain, shortness of breath, and leg pain during exercise, as objective and subjective evaluation indicators. As a key issue, HR estimation upon signal corruption due to motion artifacts is also considered. Through the smartphone-based CRP, we estimated the HR accuracy as mean absolute error and root mean squared error of 6.16 and 4.30bpm, respectively, with signal corruption due to motion artifacts being detected by combining the turning point ratio and kurtosis. PMID:27551969

  14. 76 FR 44872 - Effective Date of Requirement for Premarket Approval for an Implantable Pacemaker Pulse Generator

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-27

    ... fainting. 3. Arrhythmias A sensing failure of the pacemaker during vulnerable periods of the cardiac cycle can induce cardiac arrhythmias, in particular, dangerously fast arrhythmias. In this case, dangerously fast arrhythmias may lead to chest pain, shortness of breath, dizziness, fainting or even death....

  15. 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

  16. [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.

  17. 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.

  18. 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)

  19. Position paper for management of elderly patients with pacemakers and implantable cardiac defibrillators: Groupe de Rythmologie et Stimulation Cardiaque de la Société Française de Cardiologie and Société Française de Gériatrie et Gérontologie.

    PubMed

    Fauchier, Laurent; Alonso, Christine; Anselme, Frederic; Blangy, Hugues; Bordachar, Pierre; Boveda, Serge; Clementy, Nicolas; Defaye, Pascal; Deharo, Jean-Claude; Friocourt, Patrick; Gras, Daniel; Halimi, Franck; Klug, Didier; Mansourati, Jacques; Obadia, Benjamin; Pasquié, Jean-Luc; Pavin, Dominique; Sadoul, Nicolas; Taieb, Jerome; Piot, Olivier; Hanon, Olivier

    2016-10-01

    Despite the increasingly high rate of implantation of pacemakers (PMs) and implantable cardioverter defibrillators (ICDs) in elderly patients, data supporting their clinical and cost-effectiveness in this age stratum are ambiguous and contradictory. We reviewed the data regarding the applicability, safety and effectiveness of conventional pacing, ICDs and cardiac resynchronization therapy (CRT) in elderly patients. Although periprocedural risk may be slightly higher in the elderly, the implantation procedure for PMs and ICDs is still relatively safe in this age group. In older patients with sinus node disease, the general consensus is that DDD pacing with the programming of an algorithm to minimize ventricular pacing is preferred. In very old patients presenting with intermittent or suspected atrioventricular block, VVI pacing may be appropriate. In terms of correcting potentially life-threatening arrhythmias, the effectiveness of ICD therapy is similar in older and younger individuals. However, the assumption of persistent ICD benefit in the elderly population is questionable, as any advantageous effect of the device on arrhythmic death may be attenuated by higher total non-arrhythmic mortality. While septuagenarians and octogenarians have higher annual all-cause mortality rates, ICD therapy may remain effective in selected patients at high risk of arrhythmic death and with minimum comorbidities despite advanced age. ICD implantation among the elderly, as a group, may not be cost-effective, but the procedure may reach cost-effectiveness in those expected to live more than 5-7years after implantation. Elderly patients usually experience significant functional improvement after CRT, similar to that observed in middle-aged patients. Management of CRT non-responders remains globally the same, while considering a less aggressive approach in terms of reinterventions (revision of left ventricular [LV] lead placement, addition of a right ventricular or LV lead, LV

  20. Position paper for management of elderly patients with pacemakers and implantable cardiac defibrillators Groupe de rythmologie et stimulation cardiaque de la Société française de cardiologie et Société française de gériatrie et gérontologie.

    PubMed

    Fauchier, Laurent; Alonso, Christine; Anselme, Frédéric; Blangy, Hugues; Bordachar, Pierre; Boveda, Serge; Clementy, Nicolas; Defaye, Pascal; Deharo, Jean-Claude; Friocourt, Patrick; Gras, Daniel; Halimi, Franck; Klug, Didier; Mansourati, Jacques; Obadia, Benjamin; Pasquié, Jean-Luc; Pavin, Dominique; Sadoul, Nicolas; Taieb, Jérôme; Piot, Olivier; Hanon, Olivier

    2016-09-01

    Despite the increasingly high rate of implantation of pacemakers (PM) and cardioverter-defibrillators (ICD) in elderly patients, data supporting their clinical and cost-effectiveness in this age stratum are ambiguous and contradictory. We reviewed the data regarding the applicability, safety, and effectiveness of the conventional pacing, ICD and cardiac resynchronization therapy (CRT) in elderly patients. Although peri-procedural risk may be slightly higher in the elderly, the procedure of implantation of PMs and ICDs is still relatively safe in this age group. In older patients with sinus node disease, a general consensus is that dual chamber pacing, along with the programming of an algorithm to minimise ventricular pacing is preferred. In very old patients presenting with intermittent or suspected AV block, VVI pacing may be appropriate. In terms of correcting potentially life-threatening arrhythmias, the effectiveness of ICD therapy is comparable in older and younger individuals. However, the assumption of persistent ICD benefit in the elderly population is questionable, as any advantage of the device on arrhythmic death may be attenuated by a higher total non-arrhythmic mortality. While septuagenarians and octogenarians have higher annual all-cause mortality rates, ICD therapy may remain effective in selected patients at high risk of arrhythmic death and with minimum comorbidities despite advanced age. ICD implantation among the elderly, as a group, may not be cost-effective, but the procedure may reach cost-effectiveness in those expected to live >5-7 years after implantation. The elderly patients usually experience a significant functional improvement after CRT, similar to that observed in middle-aged patients. Management of CRT non responders remains globally the same, while considering a less aggressive approach in terms of re interventions (revision of LV lead placement, addition of a RV or LV lead, LV endocardial pacing configuration). Overall, age

  1. How Does a Pacemaker Work?

    MedlinePlus

    ... consists of a battery, a computerized generator, and wires with sensors at their tips. (The sensors are ... are surrounded by a thin metal box. The wires connect the generator to the heart. A pacemaker ...

  2. 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.

  3. Cardiac resynchronization therapy and phase resetting of the sinoatrial node: a conjecture.

    PubMed

    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

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. Gene- and cell-based bio-artificial pacemaker: what basic and translational lessons have we learned?

    PubMed

    Li, R A

    2012-06-01

    Normal rhythms originate in the sino-atrial node, a specialized cardiac tissue consisting of only a few thousands of nodal pacemaker cells. Malfunction of pacemaker cells due to diseases or aging leads to rhythm generation disorders (for example, bradycardias and sick-sinus syndrome (SSS)), which often necessitate the implantation of electronic pacemakers. Although effective, electronic devices are associated with such shortcomings as limited battery life, permanent implantation of leads, lead dislodging, the lack of autonomic responses and so on. Here, various gene- and cell-based approaches, with a particular emphasis placed on the use of pluripotent stem cells and the hyperpolarization-activated cyclic nucleotide-gated-encoded pacemaker gene family, that have been pursued in the past decade to reconstruct bio-artificial pacemakers as alternatives will be discussed in relation to the basic biological insights and translational regenerative potential.

  9. Pacemaking Kisspeptin Neurons

    PubMed Central

    Kelly, Martin J.; Zhang, Chunguang; Qiu, Jian; Rønnekleiv, Oline K.

    2013-01-01

    Kisspeptin (Kiss1) neurons are vital for reproduction. GnRH neurons express the kisspeptin receptor, GPR 54, and kisspeptins potently stimulate the release of GnRH by depolarising and inducing sustained action potential firing in GnRH neurons. As such Kiss1 neurons may be the pre-synaptic pacemaker neurons in the hypothalamic circuitry that controls reproduction. There are at least two different populations of Kiss1 neurons: one in the rostral periventricular area (RP3V) that is stimulated by oestrogens and the other in the arcuate nucleus that is inhibited by oestrogens. How each of these Kiss1 neuronal populations participate in the regulation of the reproductive cycle is currently under intense investigation. Based on electrophysiological studies in the guinea pig and mouse, Kiss1 neurons in general are capable of generating burst firing behavior. Essentially all Kiss1 neurons, which have been studied thus far in the arcuate nucleus, express the ion channels necessary for burst firing, which include hyperpolarization-activated, cyclic nucleotide gated cation (HCN) channels and the T-type calcium (Cav3.1) channels. Under voltage clamp conditions, these channels produce distinct currents that under current clamp conditions can generate burst firing behavior. The future challenge is to identify other key channels and synaptic inputs involved in the regulation of the firing properties of Kiss1 neurons and the physiological regulation of the expression of these channels and receptors by oestrogens and other hormones. The ultimate goal is to understand how Kiss1 neurons control the different phases of GnRH neurosecretion and hence reproduction. PMID:23884368

  10. Pacemaker-associated Bacillus cereus endocarditis.

    PubMed

    Barraud, Olivier; Hidri, Nadia; Ly, Kim; Pichon, Nicolas; Manea, Petrus; Ploy, Marie-Cécile; Garnier, Fabien

    2012-11-01

    We report the case of a pacemaker-associated Bacillus cereus endocarditis in a nonimmunocompromised patient. Antibiotic treatment was ineffective, and the pacemaker had to be removed. B. cereus was cultured from several blood samples and from the pacemaker electrodes. This case underlines the contribution of the rpoB gene for Bacillus species determination.

  11. 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... DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker charger is a device used transcutaneously to recharge the batteries of a...

  12. 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... DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker charger is a device used transcutaneously to recharge the batteries of a...

  13. 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... DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker charger is a device used transcutaneously to recharge the batteries of a...

  14. 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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3700 Pacemaker programmers. (a) Identification. A pacemaker programmer is a device used to change noninvasively one or more...

  15. 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... DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker charger is a device used transcutaneously to recharge the batteries of a...

  16. 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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3700 Pacemaker programmers. (a) Identification. A pacemaker programmer is a device used to change noninvasively one or more...

  17. 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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3700 Pacemaker programmers. (a) Identification. A pacemaker programmer is a device used to change noninvasively one or more...

  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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3700 Pacemaker programmers. (a) Identification. A pacemaker programmer is a device used to noninvasively change one or more...

  19. 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... DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker charger is a device used transcutaneously to recharge the batteries of a...

  20. 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

  1. 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

  2. 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.

  3. Electrical interference in non-competitive pacemakers.

    PubMed

    Sowton, E; Gray, K; Preston, T

    1970-09-01

    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.

  4. [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.

  5. [Benefits of a cardiac rehabilitation program on some parameters of corporal composition].

    PubMed

    López Frías, Magdalena; Gómez Martínez, Mar; Ramírez López Frías, Mercedes; De Teresa Galván, Carlos; Díaz Castro, Javier; Nestares, Teresa

    2014-12-01

    The cardiovascular diseases (CVD) are the principal reasons of morbidity and mortality in the world. The cardiac rehabilitation is a program of secondary prevention to complement the effects of the cardiological treatment with the participation of the patient in the control of their habits of life, as a way of promotion of its own cardiovascular health. The aim of the present study is to evaluate the long-term effects of a cardiac rehabilitation program on some parameters of corporal composition in patients that have attended or not, to the phase the III of the program. The study was performed in subjects that suffered a cardiovascular event and they were members of the Association of Cardiac Patients of Granada and Province. All the members were offered the possibility of forming a part of the study. Some parameters of body composition were measured and a nutritional evaluation was performed in all the subjects. The visceral and body fat and, which play a key role in the cardiovascular pathology, are lower in the patients attending to the cardiac rehabilitation program, revealing that are better predictors of the cardiovascular risk. Thanks to the nutritional advice received, an increase in healthy nutrients is observed and the subjects attending to the program feature major phase angle, indicating that they have a better state of hydration, together with a better integrity of the cell membranes and distribution of water between the compartments intra- and extracellular compartments.

  6. Cardiac autonomic function in patients with diabetes improves with practice of comprehensive yogic breathing program

    PubMed Central

    Jyotsna, Viveka P.; Ambekar, Smita; Singla, Rajiv; Joshi, Ansumali; Dhawan, Anju; Kumar, Neeta; Deepak, K. K.; Sreenivas, V.

    2013-01-01

    Background: The aim of this study was to observe the effect comprehensive yogic breathing (Sudarshan Kriya Yoga [SKY] and Pranayam) had on cardiac autonomic functions in patients with diabetes. Materials and Methods: This is a prospective randomized controlled intervention trial. Cardiac autonomic functions were assessed in 64 diabetics. Patients were randomized into two groups, one group receiving standard therapy for diabetes and the other group receiving standard therapy for diabetes and comprehensive yogic breathing program. Standard therapy included dietary advice, brisk walking for 45 min daily, and administration of oral antidiabetic drugs. Comprehensive yogic breathing program was introduced to the participants through a course of 12 h spread over 3 days. It was an interactive session in which SKY, a rhythmic cyclical breathing, preceded by Pranayam is taught under the guidance of a certified teacher. Cardiac autonomic function tests were done before and after 6 months of intervention. Results: In the intervention group, after practicing the breathing techniques for 6 months, the improvement in sympathetic functions was statistically significant (P 0.04). The change in sympathetic functions in the standard therapy group was not significant (P 0.75). Parasympathetic functions did not show any significant change in either group. When both parasympathetic and sympathetic cardiac autonomic functions were considered, there was a trend toward improvement in patients following comprehensive yogic breathing program (P 0.06). In the standard therapy group, no change in cardiac autonomic functions was noted (P 0.99). Conclusion: Cardiac autonomic functions improved in patients with diabetes on standard treatment who followed the comprehensive yogic breathing program compared to patients who were on standard therapy alone. PMID:23869306

  7. 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.

  8. 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)

  9. Effect of a cardiac rehabilitation program on exercise oscillatory ventilation in Japanese patients with heart failure.

    PubMed

    Yamauchi, Fumitake; Adachi, Hitoshi; Tomono, Jun-Ichi; Toyoda, Shigeru; Iwamatsu, Koichi; Sakuma, Masashi; Nakajima, Toshiaki; Oshima, Shigeru; Inoue, Teruo

    2016-10-01

    Although exercise oscillatory ventilation has emerged as a potent independent risk factor for adverse prognosis in heart failure, it is not well known whether cardiac rehabilitation can improve oscillatory ventilation. In this study, we investigated the magnitude of oscillations in ventilation before and after cardiac rehabilitation in chronic heart failure patients with exercise oscillatory ventilation. Cardiac rehabilitation (5-month program) was performed in 26 patients with chronic heart failure who showed an oscillatory ventilation pattern during cardiopulmonary exercise testing (CPX). After the 5-month rehabilitation program was completed, the patients again underwent CPX. To determine the magnitude of oscillations in ventilation, the amplitude and cycle length of the oscillations were calculated and compared with several other parameters, including biomarkers that have established prognostic value in heart failure. At baseline before cardiac rehabilitation, both oscillation amplitude (R = 0.625, P < 0.01) and cycle length (R = 0.469, P < 0.05) were positively correlated with the slope of minute ventilation vs. carbon dioxide production. Plasma BNP levels were positively correlated with amplitude (R = 0.615, P < 0.01) but not cycle length (R = 0.371). Cardiac rehabilitation decreased oscillation amplitude (P < 0.01) but failed to change cycle length. The change in amplitude was positively correlated with the change in BNP levels (R = 0.760, P < 0.01). Multiple regression analysis showed that only the change in amplitude was an independent predictor of the change in BNP levels (R = 0.717, P < 0.01). A 5-month cardiac rehabilitation program improves exercise oscillatory ventilation in chronic heart failure patients by reducing the oscillation amplitude. This effect is associated with a reduction of plasma BNP levels, potentially contributing to an improvement of heart failure.

  10. Evaluating compliance to a cardiac rehabilitation program in a private general hospital

    PubMed Central

    Mair, Vanessa; Breda, Ana Paula; Nunes, Marcos Eduardo Boquembuzo; de Matos, Luciana Diniz Nagem Janot

    2013-01-01

    ABSTRACT Objective: Identify the primary factors that influenced the participant in our cardiovascular rehabilitation program towards missing their therapy sessions, and to correlate those factors with age, cardiovascular risk, and motivation of our population. Methods: We conducted a retrospective study with 42 patients (69.15±13.93 years) participating in the cardiac rehabilitation program at a general hospital in São Paulo, through the analysis of two scales applied during the initial evaluation: Cardiac Rehabilitation Barriers Scale and scale of the original provision. We used Spearman correlation to relate them to absenteeism, cardiovascular risk age and duration of cardiac rehabilitation. Results: The total score of barriers was 31±6 and the mean score of 1.47±0.31. The main barriers subscales were related to “travel/labor dispute” and “personal problems/family.” The percentage of absenteeism was 8.4% in the number of sessions that could be made in the month. The faults and cancellations were positively correlated with cardiovascular risk (p=0.01; r=0.4) and negatively with scale provision of baseline (p=0.03; r=-0.35) and age (p=0.02; r=-0.35). Conclusion: “Travel/labor dispute”, “personal/ family problems”, and low initial provision are the main factors absenteism in a cardiac rehabilitation program in a general hospital in São Paulo. PMID:24136752

  11. 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.

  12. Pacemaker-mediated tachycardia: engineering solutions.

    PubMed

    Calfee, R V

    1988-11-01

    This discussion summarizes the interaction of refractory periods and upper rate behaviors in modern dual-chamber demand (DDD) devices, the data regarding and nine events initiating VA conduction and engineering solutions proposed and/or implemented to address the problem of pacemaker-mediated tachycardia (PMT). Among the causes of PMT are premature atrial depolarization, loss of atrial capture, a return to the demand mode after asynchronous magnet mode pacing, programming from a mode that does not guarantee AV synchrony to a mode in which atrial tracking can occur, noise, certain situations involving Wenckebach behavior, loss of sensing, and the inability of a rate-smoothing algorithm to allow a rapid change in ventricular rate. Engineering solutions to prevent the occurrence of PMT include a programmable postventricular atrial refractory period (PVARP), differential AV delay, adaptive AV delay, and the ability to discriminate between P waves of atrial origin and those resulting from retrograde conduction from the ventricle. Features such as the ability to lengthen the PVARP for one cycle after exiting the magnet or noise reversion modes or programming to a new mode, lengthen the PVARP for a single cycle following a PVC or revert to DVI pacing for one cycle following a PVC have been developed to recognize initiating events. A third solution, a tachycardia termination algorithm, can recognize and terminate PMT; varying the AV delay to determine whether P waves move in a corresponding manner and using a metabolic sensor to confirm the need for a fast heart rate are other possibilities in the detection of PMT. Diagnostic data features may also be used to evaluate the appropriateness of programmed settings. This discussion concludes that PMT is no longer a significant clinical entity when more advanced DDD pacemakers are utilized.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Evaluation of bluetooth low power for physiological monitoring in a home based cardiac rehabilitation program.

    PubMed

    Martin, Timothy; Ding, Hang; D'Souza, Matthew; Karunanithi, Mohan

    2012-01-01

    Cardiovascular disease (CVD) is the leading cause of mortality in Australia, and places large burdens on the healthcare system. To assist patients with CVDs in recovering from cardiac events and mediating cardiac risk factors, a home based cardiac rehabilitation program, known as the Care Assessment Platform (CAP), was developed. In the CAP program, patients are required to manually enter health information into their mobile phones on a daily basis. The manual operation is often subject to human errors and is inconvenient for some elderly patients. To improve this, an automated wireless solution has been desired. The objectives of this paper are to investigate the feasibility of implementing the newly released Bluetooth 4.0 (BT4.0) for the CAP program, and practically evaluate BT4.0 communications between a developed mobile application and some emulated healthcare devices. The study demonstrated that BT4.0 addresses usability, interoperability and security for healthcare applications, reduces the power consumption in wireless communication, and improves the flexibility of interface for software development. This evaluation study provides an essential mobile BT4.0 framework to incorporate a large range of healthcare devices for clinical assessment and intervention in the CAP program, and hence it is useful for similar development and research work of other mobile healthcare solutions.

  19. Left atrial myxoma in a patient with a biventricular pacemaker

    PubMed Central

    Przywara-Chowaniec, Brygida; Czarnecki, Łukasz; Nowalny-Kozielska, Ewa; Opara, Mariusz; Puzio, Agata; Kawecki, Damian; Wesołowski, Bartosz

    2016-01-01

    Myxomas make up about 50% of benign cardiac neoplasms. The most common location is within the left atrium. At the initial stage they do not exhibit any specific clinical symptoms, so they are often diagnosed by accident or during examinations recommended for other reasons. Here we present a case of left atrium myxoma in a patient (a man, age 68 years) with a dual chamber pacemaker. The myxoma did not reveal any clinical symptoms and was discovered in echocardiography during routine diagnostic examination preceding pacemaker implantation. The literature search made by the authors showed that this is the first recorded case of myxoma in a patient after the implantation of a biventricular pacemaker. PMID:28096843

  20. [Curriculum and expert courses on pacemaker and ICD therapy].

    PubMed

    Krämer, L-I; Griebenow, R

    2010-09-01

    The curricula "Practice of Pacemaker Therapy" and "Practice of ICD Therapy" have been developed from practical experience with the first educational courses which are necessary to fulfill the German requirements of the medical products law which restricts the application of medical products to persons with the necessary education, knowledge and experience. The corresponding courses of competence under the auspices of the German Cardiac Society derive from this legal prerequisite. Competence refers to technical knowledge in cardiac implantable electrical devices (CIEDs) and understanding of possible dysfunctions as well as substantial knowledge on arrhythmia. The two curricula form the theoretical basis for the application of CIEDs. These courses represent an offer to cardiologists and all other physicians who wish to acquire and document competency in this field. A legal obligation to participate in these competency courses does not currently exist in Germany as long as evidence can be provided that this competency has been achieved by other means. Both curricula have proven to be comprehensive and practically highly useful and have been presented by highly committed specialists with expertise in this topic at a high level. Since 2005 some 2,000 physicians have been trained in courses on pacemaker therapy and more than 1,000 physicians in courses on ICD therapy with an ongoing high level demand to be expected in the future.

  1. 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.

  2. Non-coding RNA in control of gene regulatory programs in cardiac development and disease.

    PubMed

    Philippen, Leonne E; Dirkx, Ellen; da Costa-Martins, Paula A; De Windt, Leon J

    2015-12-01

    Organogenesis of the vertebrate heart is a highly specialized process involving progressive specification and differentiation of distinct embryonic cardiac progenitor cell populations driven by specialized gene programming events. Likewise, the onset of pathologies in the adult heart, including cardiac hypertrophy, involves the reactivation of embryonic gene programs. In both cases, these intricate genomic events are temporally and spatially regulated by complex signaling networks and gene regulatory networks. Apart from well-established transcriptional mechanisms, increasing evidence indicates that gene programming in both the developing and the diseased myocardium are under epigenetic control by non-coding RNAs (ncRNAs). MicroRNAs regulate gene expression at the post-transcriptional level, and numerous studies have now established critical roles for this species of tiny RNAs in a broad range of aspects from cardiogenesis towards adult heart failure. Recent reports now also implicate the larger family of long non-coding RNAs (lncRNAs) in these processes as well. Here we discuss the involvement of these two ncRNA classes in proper cardiac development and hypertrophic disease processes of the adult myocardium. This article is part of a Special Issue entitled: Non-coding RNAs.

  3. A Percutaneously Implantable Fetal Pacemaker

    PubMed Central

    Zhou, Li; Vest, Adriana N.; Chmait, Ramen H.; Bar-Cohen, Yaniv; Pruetz, Jay; Silka, Michael; Zheng, Kaihui; Peck, Ray; Loeb, Gerald E.

    2015-01-01

    A miniaturized, self-contained pacemaker that could be implanted with a minimally invasive technique would dramatically improve the survival rate for fetuses that develop hydrops fetalis as a result of congenital heart block. We are currently validating a device that we developed to address this bradyarrhythmia. Preclinical studies in a fetal sheep model are underway to demonstrate that the device can be implanted via a minimally invasive approach, can mechanically withstand the harsh bodily environment, can induce effective contractions of the heart muscle with an adequate safety factor, and can successfully operate for the required device lifetime of three months using the previously-developed closed loop transcutaneous recharging system. PMID:25570982

  4. 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.

  5. 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.

  6. Sensing properties of pacemaker leads.

    PubMed

    Irnich, W

    1986-11-01

    It is already general practice to attribute sensing properties to geometry and surface structure of pacemaker leads. We have to analyze critically whether claims of having found leads with high sensitivity are in accordance with experimental and theoretical findings. From a model can be derived what kind of typical signal structure will originate from an electrode when an excitation wave crosses it, and what of this signal is influenced by electrode parameters. With decreasing surface area, the frequency content of the signal, the impedance, and, theoretically, the amplitude, increases. If the pacemaker characteristics are not matched to the lead properties, this inverse relationship becomes a direct one: If the input impedance is too low or the upper cut-off frequency of the bandpass is not high enough, the effective heart signal seems to be diminished with decreasing size. This, however, is more a pulse generator than a lead problem. If all pacers would possess an input impedance of greater than or equal to 100 K omega and an upper cut-off frequency of greater than or equal to 350 Hz, an attenuation of the heart signal would be less than or equal to 10% and thus, the results with different leads would be very similar and of equally high sensitivity.

  7. 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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device used to adapt a pacemaker lead so that...

  8. 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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device used to adapt a pacemaker lead so that...

  9. 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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device used to adapt a pacemaker lead so that...

  10. 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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device used to adapt a pacemaker lead so that...

  11. 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..., used to repair a pacemaker lead or to reconnect a pacemaker lead to a pacemaker generator....

  12. 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... pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has... implantable pacemaker pulse generator device that was in commercial distribution before May 28, 1976, or...

  13. Fully automated segmentation of left ventricle using dual dynamic programming in cardiac cine MR images

    NASA Astrophysics Data System (ADS)

    Jiang, Luan; Ling, Shan; Li, Qiang

    2016-03-01

    Cardiovascular diseases are becoming a leading cause of death all over the world. The cardiac function could be evaluated by global and regional parameters of left ventricle (LV) of the heart. The purpose of this study is to develop and evaluate a fully automated scheme for segmentation of LV in short axis cardiac cine MR images. Our fully automated method consists of three major steps, i.e., LV localization, LV segmentation at end-diastolic phase, and LV segmentation propagation to the other phases. First, the maximum intensity projection image along the time phases of the midventricular slice, located at the center of the image, was calculated to locate the region of interest of LV. Based on the mean intensity of the roughly segmented blood pool in the midventricular slice at each phase, end-diastolic (ED) and end-systolic (ES) phases were determined. Second, the endocardial and epicardial boundaries of LV of each slice at ED phase were synchronously delineated by use of a dual dynamic programming technique. The external costs of the endocardial and epicardial boundaries were defined with the gradient values obtained from the original and enhanced images, respectively. Finally, with the advantages of the continuity of the boundaries of LV across adjacent phases, we propagated the LV segmentation from the ED phase to the other phases by use of dual dynamic programming technique. The preliminary results on 9 clinical cardiac cine MR cases show that the proposed method can obtain accurate segmentation of LV based on subjective evaluation.

  14. 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.

  15. 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

  16. 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

  17. 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

  18. [State-of-the-art and prospects of high-tech medical aid to patients with cardiac arrhythmia based at military medical facilities].

    PubMed

    Steklov, V I

    2014-01-01

    Analysis of provision of high-tech medical aid to patients with cardiac arrhythmia based at military medical facilities showed that the available means and workforce are sufficient for the purpose. In order to facilitate access to high-tech medical aid it is necessary to equip arrhythmologic departments with up-to-date-instruments and set up cabinets of electrocardiostimulation in regional (naval) hospitals for implantation of temporary and permanent pacemakers. A program is pending for education (primary specialization) and advanced training of specialists in clinical cardiac electrophysiology, interventional and surgical arrhythmology.

  19. 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.

  20. [Behaviour of some serum enzymes after permanent pacemaker implantation (author's transl)].

    PubMed

    Cappelletti, F; Maiolino, P; Allegri, P; Barbieri, E; de Lio, U; Morlino, T; Ometto, R; Vincenzi, M

    1978-01-01

    The behaviour of some serum enzymes (CPK, LDH, alpha HBDH, SGOT) in 50 patients after permanent pacemaker implantation is outlined. Changes of each enzyme were analyzed statistically by applying Student's t test. Most significant changes are represented by the increase in CPK serum concentrations (19 cases). In 14 of them LDH isoenzymes were evaluated and in 4 patients alteration of LDH1/LDH2 ratio suggestive of cardiac "injury" were observed.

  1. 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

  2. Myoglobin-deficient mice activate a distinct cardiac gene expression program in response to isoproterenol-induced hypertrophy.

    PubMed

    Molojavyi, Andrei; Lindecke, Antje; Raupach, Annika; Moellendorf, Sarah; Köhrer, Karl; Gödecke, Axel

    2010-04-01

    Myoglobin knockout mice (myo-/-) adapt to the loss of myoglobin by the activation of a variety of compensatory mechanisms acting on the structural and functional level. To analyze to what extent myo-/- mice would tolerate cardiac stress we used the model of chronic isoproterenol application to induce cardiac hypertrophy in myo-/- mice and wild-type (WT) controls. After 14 days of isoproterenol infusion cardiac hypertrophy in WT and myo-/- mice reached a similar level. WT mice developed lung edema and left ventricular dilatation suggesting the development of heart failure. In contrast, myo-/- mice displayed conserved cardiac function and no signs of left ventricular dilatation. Analysis of the cardiac gene expression profiles using 40K mouse oligonucleotide arrays showed that isoproterenol affected the expression of 180 genes in WT but only 92 genes of myo-/- hearts. Only 40 of these genes were regulated in WT as well as in myo-/- hearts. In WT hearts a pronounced induction of genes of the extracellular matrix occurred suggesting a higher level of cardiac remodeling. myo-/- hearts showed altered transcription of genes involved in carbon metabolism, inhibition of apoptosis and muscular repair. Interestingly, a subset of genes that was altered in myo-/- mice already under basal conditions was differentially expressed in WT hearts under isoproterenol treatment. In summary, our data show a high capacity of myoglobin-deficient mice to adapt to catecholamine induced cardiac stress which is associated with activation of a distinct cardiac gene expression program.

  3. Runtime Verification of Pacemaker Functionality Using Hierarchical Fuzzy Colored Petri-nets.

    PubMed

    Majma, Negar; Babamir, Seyed Morteza; Monadjemi, Amirhassan

    2017-02-01

    Today, implanted medical devices are increasingly used for many patients and in case of diverse health problems. However, several runtime problems and errors are reported by the relevant organizations, even resulting in patient death. One of those devices is the pacemaker. The pacemaker is a device helping the patient to regulate the heartbeat by connecting to the cardiac vessels. This device is directed by its software, so any failure in this software causes a serious malfunction. Therefore, this study aims to a better way to monitor the device's software behavior to decrease the failure risk. Accordingly, we supervise the runtime function and status of the software. The software verification means examining limitations and needs of the system users by the system running software. In this paper, a method to verify the pacemaker software, based on the fuzzy function of the device, is presented. So, the function limitations of the device are identified and presented as fuzzy rules and then the device is verified based on the hierarchical Fuzzy Colored Petri-net (FCPN), which is formed considering the software limits. Regarding the experiences of using: 1) Fuzzy Petri-nets (FPN) to verify insulin pumps, 2) Colored Petri-nets (CPN) to verify the pacemaker and 3) To verify the pacemaker by a software agent with Petri-network based knowledge, which we gained during the previous studies, the runtime behavior of the pacemaker software is examined by HFCPN, in this paper. This is considered a developing step compared to the earlier work. HFCPN in this paper, compared to the FPN and CPN used in our previous studies reduces the complexity. By presenting the Petri-net (PN) in a hierarchical form, the verification runtime, decreased as 90.61% compared to the verification runtime in the earlier work. Since we need an inference engine in the runtime verification, we used the HFCPN to enhance the performance of the inference engine.

  4. How Will a Pacemaker Affect My Lifestyle?

    MedlinePlus

    ... Household appliances, such as microwave ovens High-tension wires Metal detectors Industrial welders Electrical generators These devices ... could damage your pacemaker or shake loose the wires in your heart. Ask your doctor how much ...

  5. Aspergillus pacemaker endocarditis presenting as pulmonary embolism.

    PubMed

    Mateos-Colino, A; Golpe, R; González-Rodríguez, A; González-Juanatey, C; Legarra, J J; Blanco, M

    2005-06-01

    Pacemaker endocarditis (PME) is a rare but severe complication of endocardial pacemaker implantation. Fungal PME is extremely uncommon. The case of a 66-year-old female patient who was diagnosed as having a pulmonary embolus based upon the patient's clinical presentation and computed tomography angiography findings is presented. Transthoracic echocardiography demonstrated a huge vegetation attached to the pacemaker wire. The pacemaker system was removed surgically during cardiovascular bypass. The vegetation was cultured, the results of which were positive for Aspergillus spp. No risk factors for Aspergillus infection were found in the patient. She was treated with liposomal amphotericin B for 3 weeks, followed by itraconazole for 40 weeks. At 1 year later, the patient remains asymptomatic.

  6. Effects of protein kinase inhibitors on canine Purkinje fibre pacemaker depolarization and the pacemaker current i(f).

    PubMed

    Chang, F; Cohen, I S; DiFrancesco, D; Rosen, M R; Tromba, C

    1991-01-01

    1. The effects of the protein kinase inhibitors H-7 and H-8 were investigated on diastolic depolarization of the action potential with microelectrodes and on the pacemaker current if with the two-microelectrode voltage clamp in canine cardiac Purkinje fibres. 2. Both 200 microM-H-7 and 100 microM-H-8 had no significant effect on the slope of diastolic depolarization but eliminated the actions of isoprenaline (1 microM). 3. We examined the actions of H-7 and H-8 on if in the presence and absence of isoprenaline. H-7 (200 microM) shifted the pacemaker current if in the negative direction on the voltage axis, whereas 100 microM-H-8 had no significant effect by itself. Both 200 microM-H-7 and 100 microM-H-8 can reverse or prevent the actions of isoprenaline (1-5 microM) on if. 4. We applied activators of the cyclic AMP cascade down-stream to the beta-receptor, to further evaluate where H-7 and H-8 might be exerting their effects. When exposing Purkinje fibres to an adenylyl cyclase activator (forskolin, 10-50 microM), a phosphodiesterase inhibitor (IBMX, 100 microM) and a permeable cyclic AMP analogue (8-chlorophenylthio-cyclic AMP, 200 microM-1 mM), the amplitude of if was increased. H-7 and H-8 at 100-200 microM eliminated each of these actions. 5. These results suggest that a phosphorylation process is involved in the modulation of the pacemaker current, if, in Purkinje fibres. The different actions of H-7 and H-8 on basal if suggest the hypothesis that other protein kinases, possibly protein kinase C, might also be involved in regulating basal phosphorylation of if in Purkinje fibres.

  7. Effects of protein kinase inhibitors on canine Purkinje fibre pacemaker depolarization and the pacemaker current i(f).

    PubMed Central

    Chang, F; Cohen, I S; DiFrancesco, D; Rosen, M R; Tromba, C

    1991-01-01

    1. The effects of the protein kinase inhibitors H-7 and H-8 were investigated on diastolic depolarization of the action potential with microelectrodes and on the pacemaker current if with the two-microelectrode voltage clamp in canine cardiac Purkinje fibres. 2. Both 200 microM-H-7 and 100 microM-H-8 had no significant effect on the slope of diastolic depolarization but eliminated the actions of isoprenaline (1 microM). 3. We examined the actions of H-7 and H-8 on if in the presence and absence of isoprenaline. H-7 (200 microM) shifted the pacemaker current if in the negative direction on the voltage axis, whereas 100 microM-H-8 had no significant effect by itself. Both 200 microM-H-7 and 100 microM-H-8 can reverse or prevent the actions of isoprenaline (1-5 microM) on if. 4. We applied activators of the cyclic AMP cascade down-stream to the beta-receptor, to further evaluate where H-7 and H-8 might be exerting their effects. When exposing Purkinje fibres to an adenylyl cyclase activator (forskolin, 10-50 microM), a phosphodiesterase inhibitor (IBMX, 100 microM) and a permeable cyclic AMP analogue (8-chlorophenylthio-cyclic AMP, 200 microM-1 mM), the amplitude of if was increased. H-7 and H-8 at 100-200 microM eliminated each of these actions. 5. These results suggest that a phosphorylation process is involved in the modulation of the pacemaker current, if, in Purkinje fibres. The different actions of H-7 and H-8 on basal if suggest the hypothesis that other protein kinases, possibly protein kinase C, might also be involved in regulating basal phosphorylation of if in Purkinje fibres. PMID:1804968

  8. 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.

  9. Use of the automatic external defibrillator-pacemaker by ambulance personnel: the Stockport experience.

    PubMed Central

    Gray, A J; Redmond, A D; Martin, M A

    1987-01-01

    In an attempt to reduce the number of people who die from a cardiac arrest in the Stockport area ambulances were equipped with automatic external defibrillator-pacemakers, and ambulance personnel were trained in their use. Over an 18 month period ambulance personnel attended 113 patients in cardiac arrest with these devices. One patient subsequently survived, and three patients survived for up to three days. The reasons for these poor initial results include the failure of bystanders to provide cardiopulmonary resuscitation, a delay in calling for the ambulance, and too few defibrillators being available. PMID:3107727

  10. Doppler index and plasma level of atrial natriuretic hormone are improved by optimizing atrioventricular delay in atrioventricular block patients with implanted DDD pacemakers.

    PubMed

    Toda, N; Ishikawa, T; Nozawa, N; Kobayashi, I; Ochiai, H; Miyamoto, K; Sumita, S; Kimura, K; Umemura, S

    2001-11-01

    Doppler index is the sum of isovolumetric contraction time and isovolumetric relaxation time divided by ejection time and has clinical value as an index of combined systolic and diastolic myocardial performance. This crossover study compared the Doppler index and atrial natriuretic hormone (atrial natriuretic peptide) [ANP] between optimal (AV) delay and prolonged AV delay in patients with DDD pacemakers. The study included 14 patients (6 men, 8 women, age 78.4+/-9.3 [SD] years) with AV block with an implanted DDD pacemaker. AV delay was prolonged in a 25-ms, stepwise fashion starting from 125 ms to 250 ms. Pacing rate was set at 70 beats/min. Cardiac output (CO) was assessed by pulsed Doppler echocardiography, and optimal AV delay was defined as the AV delay at which CO was maximum, and an AV delay setting of 250 ms as prolonged AV delay. Plasma level of ANP and Doppler index determined by echocardiography were measured 1 week after programming. AV delay was switched to another AV delay and measurements were repeated after 1 week. Optimal AV delay was 159+/-19 ms. Doppler index was significantly lower at optimal AV delay than at prolonged AV delay (0.68+/-0.26 vs 0.92+/-0.30, P < 0.05). The plasma ANP level was significantly lower at optimal AV delay than at prolonged AV delay (29.0+/-30.7 vs 52.6+/-44.9 pg/mL, P < 0.05). In conclusion, the Doppler index and the plasma ANP level were significantly lower at optimal AV delay than at prolonged AV delay. This study shows the importance of the optimal AV delay setting in patients with an implanted DDD pacemaker, the Doppler index and plasma ANP levels are good indicators for optimizing AV delay.

  11. Cardiac dimensions in athletes in relation to variations in their training program.

    PubMed

    Snoeckx, L H; Abeling, H F; Lambregts, J A; Schmitz, J J; Verstappen, F T; Reneman, R S

    1983-01-01

    The cardiac dimensions of male long-distance runners (LDR) and cycle racers (CR) were determined echocardiographically during four different training seasons, i.e., a preparation, a competitive, a slowing-down and a resting season, and were compared with those of control subjects (CS). Left ventricular hypertrophy (LVH) was also assessed from the electrocardiogram. The maximal aerobic performance was determined on a bicycle ergometer. In the athletes, left ventricular mass was significantly greater in all seasons than the values in the CS. This difference resulted from a thicker interventricular septum and left ventricular posterior wall as well as a larger left ventricular internal diameter. The existence of LVH was confirmed by the electrocardiographic findings. No differences were observed between the four different training seasons, despite considerable changes in the training program for weeks to months. The maximal aerobic performance test in LDR showed a significantly higher workload during the competitive than during the preparation season. The CR reached significantly lower values during the resting season than during the other seasons. The results indicate that the possible adaptation of the cardiac dimensions to variations in the heaviness of the training program is relatively slow.

  12. 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.

  13. Deactivation of Pacemakers and Implantable Cardioverter-Defibrillators

    PubMed Central

    Kramer, Daniel B.; Mitchell, Susan L.; Brock, Dan W.

    2013-01-01

    Cardiac implantable electrical devices (CIEDs), including pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs), are the most effective treatment for life-threatening arrhythmias. Patients or their surrogates may request device deactivation to avoid prolongation of the dying process or in other settings, such as after device-related complications or with changes in their health care goals. Despite published guidelines outlining theoretical and practical aspects of this common clinical scenario, significant uncertainty remains for both patients and health care providers regarding the ethical and legal status of CIED deactivation. This review outlines the ethical and legal principles supporting CIED deactivation at patients’ request, centered upon patient autonomy and authority over their own medical treatment. The empirical literature describing stakeholder views and experiences surrounding CIED deactivation is described, along with lessons for future research and practice guidance surrounding the care of patients with CIEDs. PMID:23217433

  14. Sudden cardiac arrest in schools: the role of the school nurse in AED program implementation.

    PubMed

    Boudreaux, Sharon; Broussard, Lisa

    2012-01-01

    A school nurse has many obstacles to overcome when providing emergency care for an age group ranging from four to adulthood. The 21st century school nurse faces the challenges of providing care to medically fragile children at multiple sites, with high student-nurse ratios. The implementation of an Automated External Defibrillation (AED) program can assist the school nurse and staff in providing necessary life-saving services for Sudden Cardiac Arrest (SCA) victims of all ages. The purpose of this article is to describe AED program implementation in a school setting, including the need, essential elements, benefits, and potential concerns related to this vital component of the American Heart Association five-link chain of survival.

  15. '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.

  16. Cost-Utility Analysis of a Cardiac Telerehabilitation Program: The Teledialog Project

    PubMed Central

    Kidholm, Kristian; Rasmussen, Maja Kjær; Andreasen, Jan Jesper; Hansen, John; Nielsen, Gitte; Spindler, Helle

    2016-01-01

    Abstract Background: Cardiac rehabilitation can reduce mortality of patients with cardiovascular disease, but a frequently low participation rate in rehabilitation programs has been found globally. The objective of the Teledialog study was to assess the cost-utility (CU) of a cardiac telerehabilitation (CTR) program. The aim of the intervention was to increase the patients' participation in the CTR program. At discharge, an individualized 3-month rehabilitation plan was formulated for each patient. At home, the patients measured their own blood pressure, pulse, weight, and steps taken for 3 months. Materials and Methods: The analysis was carried out together with a randomized controlled trial with 151 patients during 2012–2014. Costs of the intervention were estimated with a health sector perspective following international guidelines for CU. Quality of life was assessed using the 36-Item Short Form Health Survey. Results: The rehabilitation activities were approximately the same in the two groups, but the number of contacts with the physiotherapist was higher among the intervention group. The mean total cost per patient was €1,700 higher in the intervention group. The quality-adjusted life-years (QALYs) gain was higher in the intervention group, but the difference was not statistically significant. The incremental CU ratio was more than €400,000 per QALY gained. Conclusions: Even though the rehabilitation activities increased, the program does not appear to be cost-effective. The intervention itself was not costly (less than €500), and increasing the number of patients may show reduced costs of the devices and make the CTR more cost-effective. Telerehabilitation can increase participation, but the intervention, in its current form, does not appear to be cost-effective. PMID:26713491

  17. What Is Cardiac Rehabilitation?

    MedlinePlus

    ANSWERS by heart Treatments + Tests What Is Cardiac Rehabilitation? A cardiac rehabilitation (rehab) program takes place in a hospital or ... special help in making lifestyle changes. During your rehabilitation program you’ll… • Have a medical evaluation to ...

  18. How to test mode switching in pacemakers implanted in patients: the MOST study.

    PubMed

    Padeletti, Luigi; Gasparini, Maurizio; Porciani, Maria Cristina; Pieragnoli, Paolo; Colella, Andrea; Michelucci, Antonio; Proclemer, Alessandro; Tognarini, Stefano; Mantica, Massimo; Coltorti, Fernando; Corbucci, Giorgio; Sutton, Richard

    2002-02-01

    Optimal management of atrial arrhythmias with dual chamber pacemakers requires proper performance of automatic mode switching (AMS). The aim of this study was to develop a reliable technique to test the AMS function by using an external electronic device capable of mimicking the occurrence of supraventricular arrhythmias (Supraventricular Arrhythmia Simulator [SAS]). The SAS delivers low voltage pulse trains (200 mV, 20 ms) through two skin electrodes. Each pulse train lasts 15 seconds and starts synchronously with a pacing pulse of the implanted pacemaker to avoid interference from the operator. The pulse train rate is set at 350, 250, and 160 beats/min to simulate AF, atrial flutter, and atrial tachycardia (AT), respectively. Thirty-five patients implanted with Vitatron pacemakers, whose AMS system has been previously validated, were enrolled. Atrial and ventricular sensing were programmed in unipolar mode at 0.5 mV and in bipolar mode at > 2 mV, respectively. All pulses from the SAS were detected by the atrial channel at an amplitude ranging from 1 to 3 mV. The test proved to be safe and reliable at rest and during exercise. AMS occurred immediately at onset or at offset of atrial arrhythmias, and no adverse interference on pacemaker function was seen from the SAS. In conclusion, the described technique and the SAS are safe and reliable for patient and pacemaker function and can be proposed as a useful method to verify proper performance of AMS function irrespective of the type of implanted devices.

  19. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead adaptor... entitled “Guidance for the Submission of Research and Marketing Applications for Permanent Pacemaker...

  20. 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

  1. Surgical Approaches to Epicardial Pacemaker Placement: Does Pocket Location Affect Lead Survival?

    PubMed Central

    Lichtenstein, Brian J.; Bichell, David P.; Connolly, Dana M.; Lamberti, John J.; Shepard, Suzanne M.

    2010-01-01

    Permanent cardiac pacing in pediatric patients presents challenges related to small patient size, complex anatomy, electrophysiologic abnormalities, and limited access to cardiac chambers. Epicardial pacing currently remains the conventional technique for infants and patients with complex congenital heart disease. Pacemaker lead failure is the major source of failure for such epicardial systems. The authors hypothesized that a retrocostal surgical approach would reduce the rate of lead failure due to fracture compared with the more traditional subrectus and subxiphoid approaches. To evaluate this hypothesis, a retrospective chart review analyzed patients with epicardial pacemaker systems implanted or followed at Rady Children’s Hospital San Diego between January 1980 and May 2007. The study cohort consisted of 219 patients and a total of 620 leads with epicardial pacemakers. Among these patients, 84% had structural congenital heart disease, and 45% were younger than 3 years at time of the first implantation. The estimated lead survival was 93% at 2 years and 83% at 5 years. The majority of leads failed due to pacing problems (54%), followed by lead fracture (31%) and sensing problems (14%). When lead failure was adjusted for length of follow-up period, no significant differences in the rates of failure by pocket location were found. PMID:20690018

  2. [New pacemaker functions: which ones represent real progress and which are only gadgets?].

    PubMed

    Dodinot, B

    2000-07-01

    Modern pacemakers, and particularly dual chamber models, include a broad array of therapeutic and diagnostic features. Some are designed to increase safety, whereas others are either designed to avoid unnecessary pacing, reduce the current drain and increase the pacemaker longevity, or to improve the hemodynamics. Diagnostic features are more elaborate, more or less automatic, and easier to extract from the pacemaker memory. Some of these new algorithms represent a real advantage, while others appear to be more like gadgets than real advances. Several new algorithms should be improved in order to avoid possibly dangerous side effects. Most of these new features are of little value in the absence of postoperative programming by a well trained physician.

  3. Automatic mode switching of implantable pacemakers: I. Principles of instrumentation, clinical, and hemodynamic considerations.

    PubMed

    Lau, Chu-Pak; Leung, Sum-Kin; Tse, Hung-Fat; Barold, S Serge

    2002-06-01

    Automatic mode switching (AMS) is now a programmable function in most contemporary dual chamber pacemakers. Atrial tachyarrhythmias are detected when the sensed atrial rate exceeds a "rate-cutoff," "running average," "sensor-based physiological" rate, or using "complex" detection algorithms. AMS algorithms differ in their atrial tachyarrhythmia detection method, sensitivity, and specificity and, thus, respond differently to atrial tachyarrhythmia in terms of speed to the AMS onset, rate stability of the response, and speed to resynchronize to sinus rhythm. AMS is hemodynamically beneficial, and most patients with atrial tachyarrhythmias are symptomatically better with an AMS algorithm in their pacemakers. New diagnostic capabilities of pacemaker especially stored electrograms not only allow programming of the AMS function, but enable quantification of atrial fibrillation burden that facilitate clinical management of patients with implantable devices who have concomitant atrial tachyarrhythmia.

  4. 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...) 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...

  5. 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...) 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...

  6. 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...

  7. 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...

  8. 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...) 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...

  9. 21 CFR 870.3710 - Pacemaker repair or replacement material.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Section 870.3710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... adhesive, a sealant, a screw, a crimp, or any other material used to repair a pacemaker lead or to reconnect a pacemaker lead to a pacemaker pulse generator. (b) Classification. Class III (premarket...

  10. 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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold...

  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... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3710 Pacemaker repair or replacement material. (a) Identification. A pacemaker repair or replacement material is...

  12. 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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold...

  13. 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...

  14. 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... (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...

  15. 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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3730 Pacemaker service tools. (a) Identification. Pacemaker service tools are devices such as screwdrivers and Allen...

  16. 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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold...

  17. 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...

  18. 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... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3710 Pacemaker repair or replacement material. (a) Identification. A pacemaker repair or replacement material is...

  19. 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... (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 870.3710 - 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... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3710 Pacemaker repair or replacement material. (a) Identification. A pacemaker repair or replacement material is...

  1. 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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold...

  2. 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...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold...

  3. 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... pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has...

  4. 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... Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker...

  5. 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... generator function analyzer. (a) Identification. A pacemaker generator function analyzer is a device that is connected to a pacemaker pulse generator to test any or all of the generator's parameters, including...

  6. 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... Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker...

  7. 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... generator function analyzer. (a) Identification. A pacemaker generator function analyzer is a device that is connected to a pacemaker pulse generator to test any or all of the generator's parameters, including...

  8. 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... generator function analyzer. (a) Identification. A pacemaker generator function analyzer is a device that is connected to a pacemaker pulse generator to test any or all of the generator's parameters, including...

  9. 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... pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that...

  10. 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... generator function analyzer. (a) Identification. A pacemaker generator function analyzer is a device that is connected to a pacemaker pulse generator to test any or all of the generator's parameters, including...

  11. 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... pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has...

  12. 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... generator function analyzer. (a) Identification. A pacemaker generator function analyzer is a device that is connected to a pacemaker pulse generator to test any or all of the generator's parameters, including...

  13. 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... pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has...

  14. 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... Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker...

  15. 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... Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker...

  16. 21 CFR 870.3610 - Implantable pacemaker pulse generator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 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 SERVICES... pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that...

  17. 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... pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has...

  18. 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... pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has...

  19. 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... Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker...

  20. Pacemaking Property of RVLM Presympathetic Neurons

    PubMed Central

    Accorsi-Mendonça, Daniela; da Silva, Melina P.; Souza, George M. P. R.; Lima-Silveira, Ludmila; Karlen-Amarante, Marlusa; Amorim, Mateus R.; Almado, Carlos E. L.; Moraes, Davi J. A.; Machado, Benedito H.

    2016-01-01

    Despite several studies describing the electrophysiological properties of RVLM presympathetic neurons, there is no consensus in the literature about their pacemaking property, mainly due to different experimental approaches used for recordings of neuronal intrinsic properties. In this review we are presenting a historical retrospective about the pioneering studies and their controversies on the intrinsic electrophysiological property of auto-depolarization of these cells in conjunction with recent studies from our laboratory documenting that RVLM presympathetic neurons present pacemaking capacity. We also discuss whether increased sympathetic activity observed in animal models of neurogenic hypertension (CIH and SHR) are dependent on changes in the intrinsic electrophysiological properties of these cells or due to changes in modulatory inputs from neurons of the respiratory network. We also highlight the key role of INaP as the major current contributing to the pacemaking property of RVLM presympathetic neurons. PMID:27713705

  1. Efficacy of an early home-based cardiac rehabilitation program for patients after acute myocardial infarction

    PubMed Central

    Xu, Lin; Cai, Zekun; Xiong, Meihua; Li, Yekuo; Li, Guoying; Deng, Yu; Hau, William Kongto; Li, Shuo; Huang, Wenhua; Qiu, Jian

    2016-01-01

    Abstract Background: The effect of an early short-term home-based cardiac rehabilitation (CR) program on ventricular function in acute myocardial infarction (AMI) patients is not yet clear. The purpose of this study was to evaluate the efficacy of our CR program on the improvement of myocardial function using three-dimensional speckle tracking echocardiography (3D-STE) in AMI patients. Methods: Fifty-two AMI patients were randomly assigned to 2 groups after discharge: the rehabilitation group, which participated in an early, home-based CR program, and the control group, which received only usual care. All subjects in both groups underwent 3D-STE examinations of the left ventricle within 48 hours of percutaneous coronary intervention and again 4 weeks after discharge. Global longitudinal strain (GLS), global radial strain (GRS), global area strain (GAS), global circumferential strain (GCS), left ventricular ejection fraction (LVEF), and segmental strains were computed. The CR program was initially conducted with supervised inpatient training, followed by an unsupervised home-based training program during a 4-week follow-up. Results: We obtained segmental strains from 832 segments, of which 319 were defined as interventional segments, 179 as ischemic segments, and the remaining segments as normal segments. At the 4-week follow-up, when controlling for baseline values, the rehabilitation group showed significant improvements in GLS, GRS, GCS, GAS, LVEF, and in all of the segmental strains of the 3 subgroups compared with the control group (P <0.05). Conclusion: Our study suggests that an early, home-based CR program can greatly improve the ventricular function of AMI patients in a short period of time. PMID:28033254

  2. New cardiac surgery programs established from 1993 to 2004 led to little increased access, substantial duplication of services.

    PubMed

    Lucas, Frances Leslie; Siewers, Andrea; Goodman, David C; Wang, Dongmei; Wennberg, David E

    2011-08-01

    Despite decreasing demand for bypass surgery, 301 new cardiac surgery programs opened between 1993 and 2004. We used Medicare data to identify where the new programs opened and to assess their impact on access and efficiency. Forty-two percent of the new programs opened in communities that already had access to cardiac surgery, which suggests that their creation has led to a fight for shares of a shrinking market. New programs were much more likely to open in states that did not require them to show a certificate-of-need. Overall, travel time to the nearest cardiac surgery program changed little, which suggests that these programs have done little to improve geographic access. The duplication of services that resulted in many areas may have engendered competition based on quality, price, or both, but it may also have increased surgical rates, with unknown results. We observe that certificate-of-need requirements may help avoid unnecessary duplication of services by preventing new programs from opening in close proximity to existing ones.

  3. Brain responses to cardiac electrical stimulation: a new EEG method for evaluating cardiac sensation.

    PubMed

    Suzuki, Hideaki; Hirose, Masanori; Watanabe, Satoshi; Fukuda, Koji; Fukudo, Shin; Shimokawa, Hiroaki

    2012-01-01

    Although cardiac sensation, such as palpitation or chest pain, is common and is sometimes a malignant sign of heart diseases, the mechanism by which the human brain responds to afferent signals from the heart remains unclear. In this study, we investigated whether electrical stimulation of the heart provokes brain responses in humans. We examined 15 patients (age: 65.4 ± 3.1 years old, 11 males and 4 females) implanted with either a cardiac pacemaker or cardiac resynchronization therapy (CRT) device. Electroencephalogram (EEG) was simultaneously recorded from the vertex during right ventricular pacing at 70-100 beats/min at baseline (1.5 V) and intense (6-8 V) stimulation sessions. We evaluated brain responses to cardiac electrical stimulation by measuring cerebral potentials that were obtained by subtracting the average of 100 EEG waves triggered by cardiac pacing during baseline stimulation from those during the intense stimulation. Intense stimulation of the cardiac pacemaker or CRT device reproducibly induced cardiac sensation in 6 out of the 15 patients; namely, the remaining 9 patients showed no reproducible response. Brain responses were evident by averaging cerebral potentials from all of the 15 patients and those from 6 patients with reproducible cardiac sensation. To the best our knowledge, this is the first report that demonstrates the brain responses to cardiac electrical stimulation in humans. This new method should be useful for examining pathophysiology of cardiac diseases with pathological cardiac sensation, including cardiac anxiety and silent myocardial ischemia.

  4. Cardiac catheterization

    MedlinePlus

    Catheterization - cardiac; Heart catheterization; Angina - cardiac catheterization; CAD - cardiac catheterization; Coronary artery disease - cardiac catheterization; Heart valve - cardiac catheterization; Heart failure - ...

  5. 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

  6. 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.

  7. Cardiac Arrhythmias: Diagnosis, Symptoms, and Treatments.

    PubMed

    Fu, Du-Guan

    2015-11-01

    The cardiac arrhythmia is characterized by irregular rhythm of heartbeat which could be either too slow (<60 beats/min) or too fast (>100 beats/min) and can happen at any age. The use of pacemaker and defibrillators devices has been suggested for heart arrhythmias patients. The antiarrhythmic medications have been reported for the treatment of cardiac arrhythmias or irregular heartbeats. The diagnosis, symptoms, and treatments of cardiac arrhythmias as well as the radiofrequency ablation, tachycardia, Brugada syndrome, arterial fibrillation, and recent research on the genetics of cardiac arrhythmias have been described here.

  8. Pacemaker-Induced Transient Asynchrony Suppresses Heart Failure Progression

    PubMed Central

    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.

    2016-01-01

    Uncoordinated contraction from electromechanical delay worsens heart failure pathophysiology and prognosis, but restoring coordination with bi-ventricular pacing, known as cardiac resynchronization therapy (CRT) improves both. Not every patient, however, qualifies for CRT. Here 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 RV-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 PITA could bring the benefits of CRT to the many heart failure patients with synchronous contraction that are not CRT candidates. PMID:26702095

  9. Characterization of piezoelectric device for implanted pacemaker energy harvesting

    NASA Astrophysics Data System (ADS)

    Jay, Sunny; Caballero, Manuel; Quinn, William; Barrett, John; Hill, Martin

    2016-10-01

    Novel implanted cardiac pacemakers that are powered by energy harvesters driven by the cardiac motion and have a 40 year lifetime are currently under development. To satisfy space constraints and energy requirements of the device, silicon-based MEMS energy harvesters are being developed in the EU project (MANpower1). Such MEMS harvesters for vibration frequencies below 50 Hz have not been widely reported. In this paper, an analytical model and a 3D finite element model (FEM) to predict displacement and open circuit voltage, validated through experimental analysis using an off-the-shelf low frequency energy harvester, are presented. The harvester was excited through constant amplitude sinusoidal base displacement over a range of 20 to 70 Hz passing through its first mode natural frequency at 47 Hz. At resonance both models predict displacements with an error of less than 2% when compared to the experimental result. Comparing the two models, the application of the experimentally measured damping ratio differs for accurate displacement prediction and the differences in symmetry in the measured and modelled displacement and voltage data around the resonance frequency indicate the two piezoelectric voltage models use different fundamental equations.

  10. Comparison of Cardiac Rehabilitation Programs Combined with Relaxation and Meditation Techniques on Reduction of Depression and Anxiety of Cardiovascular Patients

    PubMed Central

    Delui, Mahdy Hassanzadeh; Yari, Maliheh; khouyinezhad, Gholamreza; Amini, Maral; Bayazi, Mohammad Hosein

    2013-01-01

    Cardiovascular disease (CVD) is a major cause of death in developed countries. Most cardiac rehabilitation programs include psychological interventions. The aim of this study was to determine the effectiveness of rehabilitation techniques in cardiac patients including psychological-physical interventions such as Meditation and Relaxation. We enrolled 45 patients with CVD and depression. The patients were allocated to 3 groups (Relaxation, Meditation and Control). There was a significant reduction on depression, systolic blood pressure and heart rate in the Meditation group compared with the control group. Our findings suggest that meditation techniques have better outcomes in cardiac patients for improving depression, reduction of systolic and diastolic blood pressure, and heart rate than relaxation techniques. PMID:24179555

  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.

  12. 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... is required to be filed with the Food and Drug Administration on or before September 20, 2012,...

  13. Prevention of pacemaker-associated contact dermatitis by polytetrafluoroethylene sheet and conduit coating of the pacemaker system.

    PubMed

    Taguchi, Takahiro; Maeba, Satoru; Sueda, Taijiro

    2014-09-01

    A 73-year-old female with sick sinus syndrome and atrial fibrillation was implanted with a ventricular demand inhibit pacemaker. She subsequently developed multiple episodes of skin irritation and necrosis. Skin patch testing revealed sensitivity to almost every component of the pacemaker system. The pacemaker was removed and replaced with a new pacemaker in which the generator was covered with a polytetrafluoroethylene (PTFE) sheet and the lead was covered with PTFE conduit. The patient suffered no further episodes of pacemaker-associated contact dermatitis.

  14. The automatic external defibrillator-pacemaker: clinical rationale and engineering design.

    PubMed

    Aronson, A L; Haggar, B

    1986-01-01

    Prompt defibrillation is the cornerstone of therapy for out-of-hospital sudden cardiac arrest. Overwhelming evidence indicates that victims whose cardiac arrest is witnessed and whose ECG rhythm is ventricular fibrillation can be successfully resuscitated, with significant prolongation of life. The automatic external defibrillator-pacemaker (AEDP) is designed to be used by family members of patients with known heart disease, by basic level technicians in emergency rescue systems, and by lay rescuers in corporate-industrial-public environments. The AEDP is designed for safety and ease of use. It incorporates a highly sensitive and specific electronic diagnostic logic. It defibrillates and paces with a unique tongue-chest electrode system or through two adhesive chest electrodes. The AEDP should be a cost-effective device for the treatment of sudden cardiac arrest and can play a major role in public health strategies for optimizing care for this enormous problem.

  15. 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.

  16. Two pacemaker channels from human heart with profoundly different activation kinetics.

    PubMed Central

    Ludwig, A; Zong, X; Stieber, J; Hullin, R; Hofmann, F; Biel, M

    1999-01-01

    Cardiac pacemaking is produced by the slow diastolic depolarization phase of the action potential. The hyperpolarization-activated cation current (If) forms an important part of the pacemaker depolarization and consists of two kinetic components (fast and slow). Recently, three full-length cDNAs encoding hyperpolarization-activated and cyclic nucleotide-gated cation channels (HCN1-3) have been cloned from mouse brain. To elucidate the molecular identity of cardiac pacemaker channels, we screened a human heart cDNA library using a highly conserved neuronal HCN channel segment and identified two cDNAs encoding HCN channels. The hHCN2 cDNA codes for a protein of 889 amino acids. The HCN2 gene is localized on human chromosome 19p13.3 and contains eight exons spanning approximately 27 kb. The second cDNA, designated hHCN4, codes for a protein of 1203 amino acids. Northern blot and PCR analyses showed that both hHCN2 and hHCN4 are expressed in heart ventricle and atrium. When expressed in HEK 293 cells, either cDNA gives rise to hyperpolarization-activated cation currents with the hallmark features of native If. hHCN2 and hHCN4 currents differ profoundly from each other in their activation kinetics, being fast and slow, respectively. We thus conclude that hHCN2 and hHCN4 may underlie the fast and slow component of cardiac If, respectively. PMID:10228147

  17. Pacemaker deactivation: withdrawal of support or active ending of life?

    PubMed

    Huddle, Thomas S; Amos Bailey, F

    2012-12-01

    In spite of ethical analyses assimilating the palliative deactivation of pacemakers to commonly accepted withdrawings of life-sustaining therapy, many clinicians remain ethically uncomfortable with pacemaker deactivation at the end of life. Various reasons have been posited for this discomfort. Some cardiologists have suggested that reluctance to deactivate pacemakers may stem from a sense that the pacemaker has become part of the patient's "self." The authors suggest that Daniel Sulmasy is correct to contend that any such identification of the pacemaker is misguided. The authors argue that clinicians uncomfortable with pacemaker deactivation are nevertheless correct to see it as incompatible with the traditional medical ethics of withdrawal of support. Traditional medical ethics is presently taken by many to sanction pacemaker deactivation when such deactivation honors the patient's right to refuse treatment. The authors suggest that the right to refuse treatment applies to treatments involving ongoing physician agency. This right cannot underwrite patient demands that physicians reverse the effects of treatments previously administered, in which ongoing physician agency is no longer implicated. The permanently indwelling pacemaker is best seen as such a treatment. As such, its deactivation in the pacemaker-dependent patient is best seen not as withdrawal of support but as active ending of life. That being the case, clinicians adhering to the usual ethical analysis of withdrawal of support are correct to be uncomfortable with pacemaker deactivation at the end of life.

  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. MRI Mode Programming for Safe Magnetic Resonance Imaging in Patients With a Magnetic Resonance Conditional Cardiac Device.

    PubMed

    Nakai, Toshiko; Kurokawa, Sayaka; Ikeya, Yukitoshi; Iso, Kazuki; Takahashi, Keiko; Sasaki, Naoko; Ashino, Sonoko; Okubo, Kimie; Okumura, Yasuo; Kunimoto, Satoshi; Watanabe, Ichiro; Hirayama, Atsushi

    2016-01-01

    Although diagnostically indispensable, magnetic resonance imaging (MRI) has been, until recently, contraindicated in patients with an implantable cardiac device. MR conditional cardiac devices are now widely used, but the mode programming needed for safe MRI has yet to be established. We reviewed the details of 41 MRI examinations of patients with a MR conditional device. There were no associated adverse events. However, in 3 cases, paced beats competed with the patient's own beats during the MRI examination. We describe 2 of the 3 specific cases because they illustrate these potentially risky situations: a case in which the intrinsic heart rate increased and another in which atrial fibrillation occurred. Safe MRI in patients with an MR conditional device necessitates detailed MRI mode programming. The MRI pacing mode should be carefully and individually selected.

  20. 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 β-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

  1. Complete Heart Block in Pregnancy: A Report of Emergency Caesarean Section in a Parturient without Pacemaker.

    PubMed

    Mohapatra, Vandana; Panda, Aparajita; Behera, Satyanarayan; Behera, Jagadish Chandra

    2016-10-01

    Management of women with Complete Heart Block (CHB) presenting without pacing, during pregnancy and labour is debatable. Temporary pacemakers have been routinely inserted for labour and birth probably to withstand any haemodynamic variations. However, due to lack of large scale prospective studies, the necessity of this procedure has not been objectively assessed. Also, the most appropriate anaesthetic technique for caesarean section in women with CHB is yet to be clarified. We report herein the case of a pregnant woman with CHB who had uneventful emergency caesarean delivery under spinal anaesthesia without temporary pacing. She was an unbooked case detected with congenital CHB first time during active labour; echocardiography showed no structural cardiac disease and her heart rate increased with atropine. We suggest further research so that guidelines could be established to prevent unnecessary morbidity and expense of temporary pacemaker insertion. Newly diagnosed cases of asymptomatic CHB in late pregnancy should be worked up for chronotropic responsiveness using atropine and responsive cases may be managed without pacemaker.

  2. 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

  3. Complete Heart Block in Pregnancy: A Report of Emergency Caesarean Section in a Parturient without Pacemaker

    PubMed Central

    Panda, Aparajita; Behera, Satyanarayan; Behera, Jagadish Chandra

    2016-01-01

    Management of women with Complete Heart Block (CHB) presenting without pacing, during pregnancy and labour is debatable. Temporary pacemakers have been routinely inserted for labour and birth probably to withstand any haemodynamic variations. However, due to lack of large scale prospective studies, the necessity of this procedure has not been objectively assessed. Also, the most appropriate anaesthetic technique for caesarean section in women with CHB is yet to be clarified. We report herein the case of a pregnant woman with CHB who had uneventful emergency caesarean delivery under spinal anaesthesia without temporary pacing. She was an unbooked case detected with congenital CHB first time during active labour; echocardiography showed no structural cardiac disease and her heart rate increased with atropine. We suggest further research so that guidelines could be established to prevent unnecessary morbidity and expense of temporary pacemaker insertion. Newly diagnosed cases of asymptomatic CHB in late pregnancy should be worked up for chronotropic responsiveness using atropine and responsive cases may be managed without pacemaker. PMID:27891405

  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.

  5. In vitro characterization of HCN channel kinetics and frequency dependence in myocytes predicts biological pacemaker functionality

    PubMed Central

    Zhao, Xin; Bucchi, Annalisa; Oren, Ronit V; Kryukova, Yelena; Dun, Wen; Clancy, Colleen E; Robinson, Richard B

    2009-01-01

    The pacemaker current, mediated by hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, contributes to the initiation and regulation of cardiac rhythm. Previous experiments creating HCN-based biological pacemakers in vivo found that an engineered HCN2/HCN1 chimeric channel (HCN212) resulted in significantly faster rates than HCN2, interrupted by 1–5 s pauses. To elucidate the mechanisms underlying the differences in HCN212 and HCN2 in vivo functionality as biological pacemakers, we studied newborn rat ventricular myocytes over-expressing either HCN2 or HCN212 channels. The HCN2- and HCN212-over-expressing myocytes manifest similar voltage dependence, current density and sensitivity to saturating cAMP concentrations, but HCN212 has faster activation/deactivation kinetics. Compared with HCN2, myocytes expressing HCN212 exhibit a faster spontaneous rate and greater incidence of irregular rhythms (i.e. periods of rapid spontaneous rate followed by pauses). To explore these rhythm differences further, we imposed consecutive pacing and found that activation kinetics of the two channels are slower at faster pacing frequencies. As a result, time-dependent HCN current flowing during diastole decreases for both constructs during a train of stimuli at a rapid frequency, with the effect more pronounced for HCN2. In addition, the slower deactivation kinetics of HCN2 contributes to more pronounced instantaneous current at a slower frequency. As a result of the frequency dependence of both instantaneous and time-dependent current, HCN2 exhibits more robust negative feedback than HCN212, contributing to the maintenance of a stable pacing rhythm. These results illustrate the benefit of screening HCN constructs in spontaneously active myocyte cultures and may provide the basis for future optimization of HCN-based biological pacemakers. PMID:19171659

  6. The effect of metal detector gates on implanted permanent pacemakers.

    PubMed

    Copperman, Y; Zarfati, D; Laniado, S

    1988-10-01

    The effect of metal detector security gates, such as are used in airports, was tested in 103 nonselected pacemaker patients. Various types of single and dual chamber units were examined, using telemetry during the test. Pulse rate and duration were measured immediately before and after the procedure. No ill effect was seen on any of the units tested, pacemaker inhibition was not observed, and programmability was not affected. Metal detector security gates have no effect on implanted permanent pacemakers.

  7. Pacemakers and Implantable Defibrillators - Multiple Languages: MedlinePlus

    MedlinePlus

    ... العربية) Pacemaker (Arabic) العربية Bilingual PDF Health Information Translations Chinese - Simplified (简体中文) Pacemaker 心脏起搏器 - 简体中文 (Chinese - Simplified) Bilingual PDF Health Information Translations Chinese - Traditional (繁體中文) Pacemaker 心臟起搏器 - 繁體中文 (Chinese - Traditional) ...

  8. 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

  9. A Rare Case of Recurrent Pacemaker Allergic Reaction

    PubMed Central

    Shittu, Muhammed; Shah, Pooja; Elkhalili, Walid; Suleiman, Addi; Shaaban, Hamid; Shah, Pradip A.; Shamoon, Fayez

    2015-01-01

    Allergic reactions to pacemaker device components are uncommon. However, when they occur, they usually mimic pacemaker infection, which results in multiple device replacements and increased morbidity burden. Here we present a 40-year-old female with pacemaker insertion due to complete heart block and who had multiple device replacements because of allergic sensitivity to various pacemaker component-encasing materials, confirmed by allergic testing to these materials. She had complete resolution of her symptoms after replacement with gold-plated device, to which she was not allergic. PMID:26240735

  10. Improved cardiac management with a disease management program incorporating comprehensive lipid profiling.

    PubMed

    McAna, John F; Goldfarb, Neil I; Couto, Joseph; Henry, Michelle A; Piefer, Gary; Rapier, George M

    2012-02-01

    The objective of this study was to evaluate the improved effectiveness of a disease management treatment protocol incorporating comprehensive lipid profiling and targeted lipid care based on lipid profile findings in patients with ischemic heart disease (IHD) or congestive heart failure (CHF) enrolled in a managed care plan. This retrospective cohort study, conducted over a 2-year period, compared outcomes between patients with a standard lipid profile to those evaluated with a comprehensive lipid profile. All adult members of the WellMed Medical Management, Inc. managed care health plan diagnosed with IHD or CHF, and continuously enrolled between July 1, 2006 and June 30, 2008, were included in the study. Cases were defined as those who had at least 1 comprehensive lipid test (the VAP [vertical auto profile] ultracentrifuge test) during this period (n=1767); they were compared to those who had no lipid testing or traditional standard lipid testing only (controls, n=289). Univariate statistics were analyzed to describe the groups, and bivariate t tests or chi-squares examined differences between the 2 cohorts. Multivariate regression analyses were performed to control for potential confounders. The results show that the case group had lower total costs ($4852.62 vs. $7413.18; P=0.0255), fewer inpatient stays (13.1% vs. 18.3% of controls; P=0.0175) and emergency department visits (11.9% vs. 15.6% of controls; P=0.0832). Prescription use and frequency of lipid measurement suggested improved control resulting from a targeted approach to managing specific dyslipidemias. A treatment protocol incorporating a comprehensive lipid profile appears to improve care and reduce utilization and costs in a disease management program for cardiac patients.

  11. 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; Granøien, 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) mL·kg (-1) min (−1), control group 32.0 (±6.2) to 32.8 (±5.8) mL·kg (−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

  12. Cardiac Rehabilitation

    MedlinePlus

    ... your risk of future heart problems, and to improve your health and quality of life. Cardiac rehabilitation programs increase ... exercise routine at home or at a local gym. You may also continue to ... health concerns. Education about nutrition, lifestyle and weight loss ...

  13. Delayed right ventricular defibrillation lead perforation presenting as cardiac tamponade and treated surgically.

    PubMed

    Noguchi, Masahiko; Nakai, Toshiko; Kawano, Yuji; Shibayama, Kentaro; Obunai, Kotaro; Tabata, Minoru; Watanabe, Hiroyuki

    2017-04-01

    Right ventricular perforation leading to cardiac tamponade can occur during the chronic phase after cardiac device implantation. Physicians who manage the pacemaker clinic must be alert to the wide range of symptoms and signs that can accompany delayed right ventricular perforation. Surgical rather than percutaneous lead extraction may be prudent.

  14. [Study on Chaotic Detection Method of Pacemaker Contact-Less Power Supply].

    PubMed

    Zhou, Chenghu; Huang, Mingming; Li, Songtao

    2015-12-01

    In order to improve the reliability of cardiac pacemaker contact-less power supply technology, this paper proposes a novel application of wireless feedback voltage stabilizing technology to adjust heart disease patients with inner power supply filter circuit output voltage and current control method, to keep the output voltage stability, and to ensure that the super capacitor and cardiac pacemaker to get a stable power supply. To implement the real-time accurate voltage control with considering the primary and secondary side inductance coupling coefficient changes, the change of the external power supply voltage and load, it is necessary to test thee real-time and accurate output voltage and current value after rectifying filtering. Therefore, based on the chaotic control theory, we adopted method of phase diagram on the basis of the quick observation after rectifying filtering, so that the method of voltage and current could improve the detection time of the circuit. The phase diagram of proposed control method can be divided into 8 segments, and we got 7 zero-extreme points. When these zero-extreme points are detected, according to extreme points of the zero instantaneous values, the corresponding average values of voltage and current were obtained. Simulation and experimental results showed that using the above method can shorten the response time to less than switch devices 1/2 switching cycles, thus validating the effectiveness and feasibility of the proposed detection algorithm.

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

    PubMed Central

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

    2012-01-01

    Abstract 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. PMID:22894470

  16. Inappropriate shock therapy for nonsustained ventricular tachycardia in a dual chamber pacemaker defibrillator.

    PubMed

    Mann, D E; Kelly, P A; Reiter, M J

    1998-10-01

    We report a patient who received a CPI Ventak AV II DR ICD for ventricular tachycardia and complete heart block without an escape rhythm. During induced nonsustained ventricular tachycardia, the device, although programmed to deliver noncommitted shocks, acted like a committed device. This phenomenon is due to undocumented behavior that is likely to occur in any patient who is pacemaker dependent and has nonsustained ventricular tachycardia.

  17. Feasibility of an exercise intervention for fatigued breast cancer patients at a community-based cardiac rehabilitation program

    PubMed Central

    De Jesus, Stefanie; Fitzgeorge, Lyndsay; Unsworth, Karen; Massel, David; Suskin, Neville; Prapavessis, Harry; Sanatani, Michael

    2017-01-01

    Purpose Exercise is beneficial to quality of life after cancer treatment, yet few cancer survivors meet exercise guidelines. Our study sought to determine the feasibility of an oncology rehabilitation exercise program embedded within a cardiac rehabilitation program. Methods Patients who rated their fatigue >4/10 after completion of adjuvant chemotherapy for breast cancer were screened for eligibility and the outcomes were assessed (Piper Fatigue Scale, Functional Assessment of Cancer Therapy-Breast [FACT-B], Edmonton Symptom Assessment System, body composition, stress test, and physical activity measurement [accelerometer]). Participants received individualized exercise prescription. Following the 16-week program, repeat assessment plus patient acceptance and satisfaction survey was completed. The primary end point was the composite of accrual rate >25%, program adherence >80%, and mean compliance with accelerometer use >80%. Results Twenty of 24 screened patients consented to the study and completed the baseline assessment. Adherence was 30.3%. Mean accelerometer use was 3.88/7 days (78%). Fatigue at baseline was rated at 4.82/10, and at 3.59 (p = 0.09) after the intervention. Overall well-being (FACT-B) score changed from 92.7 to 98.3 (p = 0.05). There were no significant changes in body composition (except for bone mineral content), aerobic exercise capacity, or activity patterns. Conclusion Although the primary outcome was not met, our study indicates that an oncology exercise rehabilitation program can be incorporated into an existing cardiac rehabilitation program. Based on feedback received, we propose that in order to achieve exercise goals, frequent, encouraging, and tailored feedback and group sessions to foster a sense of community may additionally be needed to strengthen adherence to a prescribed exercise program. PMID:28228661

  18. 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 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... tools. (a) Identification. Pacemaker service tools are devices such as screwdrivers and Allen...

  19. 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 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... tools. (a) Identification. Pacemaker service tools are devices such as screwdrivers and Allen...

  20. 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... connected to an implanted pacemaker lead that supplies an accurately calibrated, variable pacing pulse...

  1. 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... connected to an implanted pacemaker lead that supplies an accurately calibrated, variable pacing pulse...

  2. Induction of ventricular tachycardia during radiofrequency ablation via pulmonary vein ablation catheter in a patient with an implanted pacemaker.

    PubMed

    Hammwöhner, Matthias; Stachowitz, Jörg; Willich, Tobias; Goette, Andreas

    2012-02-01

    Pulmonary vein isolation in a dual-chamber pacemaker patient using the pulmonary vein ablation catheter (PVAC) system resulted in perpetual induction of ventricular tachycardia (VT) during radio frequency energy application. Induction of VT was abolished by programming the PVAC-system to a pure bipolar ablation mode. Patients with implanted devices should be closely monitored when using the PVAC system in unipolar modes.

  3. 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

  4. Effects of phase III cardiac rehabilitation programs on health-related quality of life in elderly patients with coronary artery disease: Juntendo Cardiac Rehabilitation Program (J-CARP).

    PubMed

    Seki, Eriko; Watanabe, Yoshiro; Sunayama, Satoshi; Iwama, Yoshitaka; Shimada, Kazunori; Kawakami, Kazunobu; Sato, Mizue; Sato, Hiroyuki; Mokuno, Hiroshi; Daida, Hiroyuki

    2003-01-01

    The purpose of this prospective randomized controlled trial was to assess the impact of phase III comprehensive cardiac rehabilitation (CR) on health-related quality of life (HRQOL) in elderly patients with coronary artery disease (CAD). Thirty-eight elderly males (mean age, 70 years) with CAD were stratified as the intervention group (n=20) and the control group (n=18). In the intervention group, patients participated in CR for 6 months, whereas in the control group, they received standard care. Validated questionnaires were obtained to evaluate HRQOL using the Medical Outcome Study Short-Form 36 Health Status Survey (SF-36), State-trait anxiety inventory questionnaire (STAI) and Self-rating Depression Scale (SDS) at baseline and after 6 months. At baseline, scores of SF-36 except for general health, STAI and SDS were not different in either group. After 6 months, in the intervention group, scores of bodily pain, general health, vitality and mental health of SF-36 improved significantly compared with baseline. State anxiety scores also improved significantly (p<0.01), but SDS depression scores were not improved. In the control group, none of the parameters significantly changed. These results indicate that elderly patients with CAD should be vigorously encouraged to pursue CR even in chronic phase III.

  5. Myosin helical pitch angle as a quantitative imaging biomarker for characterization of cardiac programming in fetal growth restriction measured by polarization second harmonic microscopy

    NASA Astrophysics Data System (ADS)

    Amat-Roldan, I.; Psilodimitrakopoulos, S.,; Eixarch, E.,; Torre, I.; Wotjas, B.; Crispi, F.; Figueras, F.; Artigas, D.,; Loza-Alvarez, P.; Gratacos, E.,

    2009-07-01

    Fetal growth restriction (FGR) has recently shown a strong association with cardiac programming which predisposes to cardiovascular mortality in adulthood. Polarization Second Harmonic Microscopy can quantify molecular architecture changes with high sensitivity in cardiac myofibrils. In this work, we use myosin helical pitch angle as an example to quantify such alterations related to this high risk population. Importantly, this shows a potential use of the technique as an early diagnostic tool and an alternative method to understand pathophysiological processes.

  6. Cardiac MRI

    MedlinePlus

    ... Defects Coronary Heart Disease Heart Attack Heart Failure Heart Valve Disease Send a link to NHLBI to someone by ... Disease Echocardiography Heart Attack Heart Failure Heart Palpitations Heart Valve Disease Implantable Cardioverter Defibrillators Pacemaker Pericarditis Stress Testing Rate ...

  7. 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,…

  8. Perioperative management of patients with cardiac implantable electronic devices.

    PubMed

    Poveda-Jaramillo, R; Castro-Arias, H D; Vallejo-Zarate, C; Ramos-Hurtado, L F

    2017-05-01

    The use of implantable cardiac devices in people of all ages is increasing, especially in the elderly population: patients with pacemakers, cardioverter-defibrillators or cardiac resynchronization therapy devices regularly present for surgery for non-cardiac causes. This review was made in order to collect and analyze the latest evidence for the proper management of implantable cardiac devices in the perioperative period. Through a detailed exploration of PubMed, Academic Search Complete (EBSCO), ClinicalKey, Cochrane (Ovid), the search software UpToDate, textbooks and patents freely available to the public on Google, we selected 33 monographs, which matched the objectives of this publication.

  9. 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.

  10. Small RNA-directed epigenetic programming of embryonic stem cell cardiac differentiation

    PubMed Central

    Ghanbarian, Hossein; Wagner, Nicole; Michiels, Jean-François; Cuzin, François; Wagner, Kay-Dietrich; Rassoulzadegan, Minoo

    2017-01-01

    Microinjection of small noncoding RNAs in one-cell embryos was reported in several instances to result in transcriptional activation of target genes. To determine the molecular mechanisms involved and to explore whether such epigenetic regulations could play a role in early development, we used a cell culture system as close as possible to the embryonic state. We report efficient cardiac differentiation of embryonic stem (ES) cells induced by small non-coding RNAs with sequences of Cdk9, a key player in cardiomyocyte differentiation. Transfer of oligoribonucleotides representing parts of the Cdk9 mRNA into ES and mouse embryo fibroblast cultures resulted in upregulation of transcription. Dependency on Argonaute proteins and endogenous antisense transcripts indicated that the inducer oligoribonucleotides were processed by the RNAi machinery. Upregulation of Cdk9 expression resulted in increased efficiency of cardiac differentiation suggesting a potential tool for stem cell-based regenerative medicine. PMID:28165496

  11. Small RNA-directed epigenetic programming of embryonic stem cell cardiac differentiation.

    PubMed

    Ghanbarian, Hossein; Wagner, Nicole; Michiels, Jean-François; Cuzin, François; Wagner, Kay-Dietrich; Rassoulzadegan, Minoo

    2017-02-06

    Microinjection of small noncoding RNAs in one-cell embryos was reported in several instances to result in transcriptional activation of target genes. To determine the molecular mechanisms involved and to explore whether such epigenetic regulations could play a role in early development, we used a cell culture system as close as possible to the embryonic state. We report efficient cardiac differentiation of embryonic stem (ES) cells induced by small non-coding RNAs with sequences of Cdk9, a key player in cardiomyocyte differentiation. Transfer of oligoribonucleotides representing parts of the Cdk9 mRNA into ES and mouse embryo fibroblast cultures resulted in upregulation of transcription. Dependency on Argonaute proteins and endogenous antisense transcripts indicated that the inducer oligoribonucleotides were processed by the RNAi machinery. Upregulation of Cdk9 expression resulted in increased efficiency of cardiac differentiation suggesting a potential tool for stem cell-based regenerative medicine.

  12. [Pacemaker implantation in dogs: results of the last 30 years].

    PubMed

    François, L; Chetboul, V; Nicolle, A; Carlos, C; Borenstein, N; Pouchelon, J L

    2004-07-01

    Pacemaker implantation in veterinary practice is still not well known and remains uncommon. However, this technique is the only possible way to cure animals suffering from symptomatic bradycardia whose state does not improve with a medical treatment. In most cases, the use of pacemakers in veterinary medicine leads to the disappearance of the clinical and electrocardiographic signs. This retrospective study concerning the last 30 years draws up an evaluation of the improvements, advantages and drawbacks of this method. Moreover, this study allows the understanding of the evolution of pacemakers' use in veterinary cardiology.

  13. Gene Delivery for the Generation of Bioartificial Pacemaker.

    PubMed

    Chan, Patrick K W; Li, Ronald A

    2017-01-01

    Electronic pacemakers have been used in patients with heart rhythm disorders for device-supported pacing. While effective, there are such shortcomings as limited battery life, permanent implantation of catheters, the lack of autonomic neurohumoral responses, and risks of lead dislodging. Here we describe protocols for establishing porcine models of sick sinus syndrome and complete heart block, and the generation of bioartificial pacemaker by delivering a strategically engineered form of hyperpolarization-activated cyclic nucleotide-gated pacemaker channel protein via somatic gene transfer to convert atrial or ventricular muscle cardiomyocytes into nodal-like cells that rhythmically fire action potentials.

  14. [Problems, complications, and emergencies during pacemaker implantation. Importance of access].

    PubMed

    Israel, Carsten W; Ekosso-Ejangue, Lucy

    2015-12-01

    Pacemaker implantation represents a standard procedure with a perceived 100% success rate, without mortality and with extremely rare complications. However, some pacemaker implantations may develop into a very difficult procedure or even be associated with significant complications. Good venous access is crucial and may distinguish between comfortable, successful implantation and futile implantation with severe complications (e.g., pneumo- or hematothorax, venous dissection or perforation, accidental arterial implantation, or air embolism). This review summarizes acute problems and complications during lead implantation and provides tips and hints for prevention and acute reaction during implantation. If these simple precautions are considered, the majority of acute complications during implantation of pacemaker leads can be prevented.

  15. Endogenous pacemaker activity of rat tumour somatotrophs

    PubMed Central

    Kwiecien, Renata; Robert, Christophe; Cannon, Robert; Vigues, Stephan; Arnoux, Annie; Kordon, Claude; Hammond, Constance

    1998-01-01

    Cells derived from a rat pituitary tumour (GC cell line) that continuously release growth hormone behave as endogenous pacemakers. In simultaneous patch clamp recordings and cytosolic Ca2+ concentration ([Ca2+]i) imaging, they displayed rhythmic action potentials (44.7 ± 2.7 mV, 178 ± 40 ms, 0.30 ± 0.04 Hz) and concomitant [Ca2+]i transients (374 ± 57 nM, 1.0 ± 0.2 s, 0.27 ± 0.03 Hz). Action potentials and [Ca2+]i transients were reversibly blocked by removal of external Ca2+, addition of nifedipine (1 μM) or Ni2+ (40 μM), but were insensitive to TTX (1 μM). An L-type Ca2+ current activated at -33.6 ± 0.4 mV (holding potential (Vh), −40 mV), peaked at -1.8 ± 1.3 mV, was reduced by nifedipine and enhanced by S-(+)-SDZ 202 791. A T/R-type Ca2+ current activated at -41.7 ± 2.7 mV (Vh, -80 or -60 mV), peaked at -9.2 ± 3.0 mV, was reduced by low concentrations of Ni2+ (40 μM) or Cd2+ (10 μM) and was toxin resistant. Parallel experiments revealed the expression of the class E calcium channel α1-subunit mRNA. The K+ channel blockers TEA (25 mM) and charybdotoxin (10–100 nM) enhanced spike amplitude and/or duration. Apamin (100 nM) also strongly reduced the after-spike hyperpolarization. The outward K+ tail current evoked by a depolarizing step that mimicked an action potential reversed at −69.8 ± 0.3 mV, presented two components, lasted 2–3 s and was totally blocked by Cd2+ (400 μM). The slow pacemaker depolarization (3.5 ± 0.4 s) that separated consecutive spikes corresponded to a 2- to 3-fold increase in membrane resistance, was strongly Na+ sensitive but TTX insensitive. Computer simulations showed that pacemaker activity can be reproduced by a minimum of six currents: an L-type Ca2+ current underlies the rising phase of action potentials that are repolarized by a delayed rectifier and Ca2+-activated K+ currents. In between spikes, the decay of Ca2+-activated K+ currents and a persistent inward cationic current depolarize the membrane

  16. Biodegradation of polyether polyurethane inner insulation in bipolar pacemaker leads.

    PubMed

    Wiggins, M J; Wilkoff, B; Anderson, J M; Hiltner, A

    2001-05-01

    Several bipolar coaxial pacemaker leads, composed of an outer silicone rubber insulation and an inner polyether polyurethane (PEU) insulation, which were explanted due to clinical evidence of electrical dysfunction, were analyzed in this study. Optical microscopy (OM) and scanning electron microscopy (SEM) were used to determine the cause of failure. Attenuated total reflectance-Fourier transform infrared microscopy (ATR-FTIR) was used to analyze the PEU insulation for chemical degradation. In all leads, the silicone rubber outer insulation showed no signs of physical damage. Physical damage to the inner PEU insulation was the source of electrical dysfunction. Cracks through the PEU compromised the insulation between the inner and outer conductor coils in the lead. It was observed with SEM that these cracks originated on the outer surface of the inner insulation and progressed inward. ATR-FTIR analysis showed that the PEU had chemically degraded via oxidation of the ether soft segment. Furthermore, it was revealed that chemical degradation was more advanced on the outer surface of the PEU. It was hypothesized that hydrogen peroxide permeated through the outer silicone insulation and decomposed into hydroxyl radicals that caused the chemical degradation of PEU. The metal in the outer conductor coil catalyzed the decomposition of the hydrogen peroxide. Chemical degradation of the PEU could also have been catalyzed by metal ions created from the corrosion of the metal in the outer conductor coil by hydrogen peroxide. Physical damage probably occurred in regions of the leads that were subjected to a higher hydrogen peroxide concentration from inflammatory cells and high degrees and rates of strain due to intercorporeal movement, including, but not limited to, cardiac movement. Chemical degradation and physical damage probably had a synergistic affect on failure of the insulation, in that as chemical degradation proceeded, the polymer surface became brittle and more

  17. Implantation of VVI pacemaker in a patient with dextrocardia, persistent left superior vena cava, and sick sinus syndrome

    PubMed Central

    Guo, Gongliang; Yang, Lili; Wu, Jinyi; Sun, Liqun

    2017-01-01

    Abstract Background: Dextrocardia, or right-lying heart, is an uncommon congenital heart disease in which the apex of the heart is located on the right side of chest. Persistent left superior vena cava (PLSVA) is a rare venous anomaly that is often associated with the abnormalities of cardiac transduction system. A case with combination of dextrocardia, persistent left superior vena cava, and sick sinus syndrome has not been reported. Methods: We used different techniques including cardiac color Doppler echocardiography, 24-hour Holter monitoring, and abdominal ultrasound to make a diagnosis and treated the patient by implanting a VVI pacemaker. Results: A 50-year-old woman was admitted with a syncope. Angiography of the right atrium and superior vena cava, echocardiography, electrocardiography, and abdominal ultrasound revealed the presence of the combination of mirror image dextrocardia, PLSVA, and sick sinus syndrome. The complex structural anomalies presented great technical challenges for interventional treatments. After thorough examination and understanding of the structural anatomy and anomalies of the superior and inferior vena cava and cardiac chambers, we successfully treated this patient by implanting a VVI pacemaker. Conclusion: Physicians must be aware of the complexity of the morphological and anatomical structures of dextrocardia accompanying PLSVC. Given that the diagnosis of situs inversus was performed at a relatively advanced age, it is therefore important to make such a correct diagnosis followed by appropriate therapeutic intervention. PMID:28151908

  18. Properties of the pacemaker current (If) in latent pacemaker cells isolated from cat right atrium.

    PubMed Central

    Zhou, Z; Lipsius, S L

    1992-01-01

    1. Single latent pacemaker cells were isolated from the Eustachian ridge of cat right atrium using Langendorff perfusion and enzyme dispersion techniques. Whole-cell patch-clamp techniques were used to study the hyperpolarization-activated inward current (I(f)). 2. All cells studied beat rhythmically. Pacemaker activity was recorded in the voltage range -68 +/- 1 to -54 +/- 2 mV and its cycle length was 901 +/- 67 ms (72 +/- 5 beats min-1) at 34-36 degrees C. Cells were elongated with tapered ends, and appeared bent or crinkled without obvious striations. Mean cell diameter and length were 7.4 +/- 0.5 microns and 93.1 +/- 5.9 microns, respectively (n = 15). Input resistance and total membrane capacitance were 2.2 +/- 0.2 G omega and 27.8 +/- 3.1 pF, respectively. 3. Hyperpolarizing clamp steps more negative than -50 mV elicited a time-dependent increasing inward current that was maximally activated at -120 mV. Activation of I(f) was well within the pacemaker voltage range. Half-maximal activation voltage and slope factor were calculated, using a Boltzmann function, to be -80.5 mV and 8.4, respectively. 4. The fully activated current-voltage (I-V) relationship was approximately linear at voltages more negative than -30 mV and showed outward rectification at more positive voltages. The reversal potential of I(f) was -26 mV and the fully activated conductance was 1.75 +/- 0.14 nS (n = 21). Caesium (2 mM) blocked I(f) at voltages more negative than the reversal potential. Reducing extracellular Na+ or K+ shifted the reversal potential more negative, and increasing extracellular K+ exerted the opposite effect. Reducing extracellular Na+ decreased I(f) amplitude and the slope of the fully activated I-V relationship, and elevated extracellular K+ increased I(f) amplitude and the slope of the fully activated I-V relationship. 5. Some pacemaker cells exhibited a short delay in the onset of I(f) activation whereas other pacemaker cells exhibited little, if any, delay in

  19. Engineered Biological Pacemakers | NCI Technology Transfer Center | TTC

    Cancer.gov

    The National Institute on Aging's Cellular Biophysics Section is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize biological pacemakers.

  20. Pacemakers and Implantable Defibrillators: MedlinePlus Health Topic

    MedlinePlus

    ... Association) How Does a Pacemaker Work? (National Heart, Lung, and Blood Institute) How Does an Implantable Cardioverter Defibrillator Work? (National Heart, Lung, and Blood Institute) Implantable Cardioverter Defibrillator (National Heart, Lung, and ...

  1. Automatic segmentation of the left ventricle in cardiac MRI using local binary fitting model and dynamic programming techniques.

    PubMed

    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.

  2. 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.

  3. Influence of Slippery Pacemaker Leads on Lead-Induced Venous Occlusion

    NASA Astrophysics Data System (ADS)

    Yang, Weiguang; Bhatia, Sagar; Obenauf, Dayna; Resse, Max; Esmaily-Moghadam, Mahdi; Feinstein, Jeffrey; Pak, On Shun

    2016-11-01

    The use of medical devices such as pacemakers and implantable cardiac defibrillators have become commonplace to treat arrhythmias. Pacing leads with electrodes are used to send electrical pulses to the heart to treat either abnormally slow heart rates, or abnormal rhythms. Lead induced vessel occlusion, which is commonly seen after placement of pacemaker or ICD leads, may result in lead malfunction and/or SVC syndrome, and makes lead extraction difficult. The association between the anatomic locations at risk for thrombosis and regions of venous stasis have been reported previously. The computational studies reveal obvious flow stasis in the proximity of the leads, due to the no-slip boundary condition imposed on the lead surface. With the advent of recent technologies capable of creating slippery surfaces that can repel complex fluids including blood, we explore computationally how local flow structures may be altered in the regions around the leads when the no-slip boundary condition on the lead surface is relaxed using various slip lengths. The findings evaluate the possibility of mitigating risks of lead-induced thrombosis and occlusion by implementing novel surface conditions (i.e. theoretical coatings) on the leads.

  4. Reflex vasovagal syncope--is there a benefit in pacemaker therapy?

    PubMed

    Sousa, Pedro Alexandre; Candeias, Rui; Marques, Nuno; Jesus, Ilídio

    2014-05-01

    Reflex vasovagal syncope often affects young populations and is associated with a benign prognosis in terms of mortality. However, a minority of patients have recurrent episodes, with a considerable impact on their quality of life. Pacemaker therapy has been an option in these patients since the 1990s if a conservative strategy fails. Initially, non-randomized and open-label randomized trials showed promising results, but these studies were associated with a significant placebo effect. Recently, an approach based on the use of implantable loop recorders has shown that some patients with reflex vasovagal syncope could benefit from implantation with dual-chamber pacemakers, particularly patients aged >40 years, with recurrent syncopal episodes resulting in frequent injuries, in whom a long asystole (≥3 s asystole with syncope or ≥6 s asystole without syncope) has been documented with an implantable loop recorder. The authors present a literature review on the role of cardiac pacing in reflex vasovagal syncope and propose a diagnostic and therapeutic decision flowchart for patients with syncope of probable reflex etiology.

  5. Delayed pacemaker lead perforations: Why unusual presentations should prompt an early multidisciplinary team approach

    PubMed Central

    Chao, John An Kuang; Firstenberg, Michael S.

    2017-01-01

    Our first case is an 84-year-old female diagnosed with sick sinus syndrome. She underwent implantation of dual chamber permanent pacemaker without complications. On the 8th day status-postimplantation, she returned to the emergency department (ED) with moderately severe left anterior chest pain and significant ecchymosis. She was given an initial diagnosis of shingles and discharged. Two days later, she returned to the ED with increasing chest pain, dyspnea, nausea, and vomiting. Lead migration and cardiac perforation was confirmed by chest X-ray and computed tomography (CT), respectively. She was taken to the operating room (OR) for lead repositioning, and she was discharged the next day. Our second case is a 64-year-old female with a diagnosis of 2:1 high-grade third-degree atrioventricular block. A dual chamber permanent pacemaker system was implanted without initial complication. Five days after implantation, she presented to the ED following an episode of syncope due to hypotension (67/46), shortness of breath, left flank pain, and fatigue. The initial diagnosis was sepsis. A chest CT was obtained, noting lead perforation and hemothorax. The patient was taken to the OR for lead repositioning. PMID:28382260

  6. Interaction of a commercial heart rate monitor with implanted pacemakers.

    PubMed

    Joglar, J A; Hamdan, M H; Welch, P J; Page, R L

    1999-03-01

    Dry-electrode heart rate monitors allow display of heart rate by transmitting a signal to the receiving device, which typically is on the wrist or exercise machine, but due to the potential for electromagnetic interference, their use has been contraindicated in patients with pacemakers. In 12 patients, we found no adverse effect on pacemaker function; in addition, the monitors generally were accurate in measuring heart rate during pacing.

  7. Pacemaker activity and ionic currents in mouse atrioventricular node cells.

    PubMed

    Marger, Laurine; Mesirca, Pietro; Alig, Jacqueline; Torrente, Angelo; Dubel, Stefan; Engeland, Birgit; Kanani, Sandra; Fontanaud, Pierre; Striessnig, Jörg; Shin, Hee-Sup; Isbrandt, Dirk; Ehmke, Heimo; Nargeot, Joël; Mangoni, Matteo E

    2011-01-01

    It is well established that Pacemaker activity of the sino-atrial node (SAN) initiates the heartbeat. However, the atrioventricular node (AVN) can generate viable pacemaker activity in case of SAN failure, but we have limited knowledge of the ionic bases of AVN automaticity. We characterized pacemaker activity and ionic currents in automatic myocytes of the mouse AVN. Pacemaking of AVN cells (AVNCs) was lower than that of SAN pacemaker cells (SANCs), both in control conditions and upon perfusion of isoproterenol (ISO). Block of I(Na) by tetrodotoxin (TTX) or of I(Ca,L) by isradipine abolished AVNCs pacemaker activity. TTX-resistant (I(Nar)) and TTX-sensitive (I(Nas)) Na(+) currents were recorded in mouse AVNCs, as well as T-(I(Ca,T)) and L-type (I(Ca,L)) Ca(2+) currents I(Ca,L) density was lower than in SANCs (51%). The density of the hyperpolarization-activated current, (I(f)) and that of the fast component of the delayed rectifier current (I(Kr)) were, respectively, lower (52%) and higher (53%) in AVNCs than in SANCs. Pharmacological inhibition of I(f) by 3 µM ZD-7228 reduced pacemaker activity by 16%, suggesting a relevant role for I(f) in AVNCs automaticity. Some AVNCs expressed also moderate densities of the transient outward K(+) current (I(to)). In contrast, no detectable slow component of the delayed rectifier current (I(Ks)) could be recorded in AVNCs. The lower densities of I(f) and I(Ca,L), as well as higher expression of I(Kr) in AVNCs than in SANCs may contribute to the intrinsically slower AVNCs pacemaking than that of SANCs.

  8. 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.

  9. Pharmacology of cardiac potassium channels.

    PubMed

    Tamargo, Juan; Caballero, Ricardo; Gómez, Ricardo; Valenzuela, Carmen; Delpón, Eva

    2004-04-01

    Cardiac K+ channels are membrane-spanning proteins that allow the passive movement of K+ ions across the cell membrane along its electrochemical gradient. They regulate the resting membrane potential, the frequency of pacemaker cells and the shape and duration of the cardiac action potential. Additionally, they have been recognized as potential targets for the actions of neurotransmitters and hormones and class III antiarrhythmic drugs that prolong the action potential duration (APD) and refractoriness and have been found effective to prevent/suppress cardiac arrhythmias. In the human heart, K+ channels include voltage-gated channels, such as the rapidly activating and inactivating transient outward current (Ito1), the ultrarapid (IKur), rapid (IKr) and slow (IKs) components of the delayed rectifier current and the inward rectifier current (IK1), the ligand-gated channels, including the adenosine triphosphate-sensitive (IKATP) and the acetylcholine-activated (IKAch) currents and the leak channels. Changes in the expression of K+ channels explain the regional variations in the morphology and duration of the cardiac action potential among different cardiac regions and are influenced by heart rate, intracellular signalling pathways, drugs and cardiovascular disorders. A progressive number of cardiac and noncardiac drugs block cardiac K+ channels and can cause a marked prolongation of the action potential duration (i.e. an acquired long QT syndrome, LQTS) and a distinct polymorphic ventricular tachycardia termed torsades de pointes. In addition, mutations in the genes encoding IKr (KCNH2/KCNE2) and IKs (KCNQ1/KCNE1) channels have been identified in some types of the congenital long QT syndrome. This review concentrates on the function, molecular determinants, regulation and, particularly, on the mechanism of action of drugs modulating the K+ channels present in the sarcolemma of human cardiac myocytes that contribute to the different phases of the cardiac action

  10. The epidemiology of pacemaker implantation in the United States.

    PubMed Central

    Silverman, B G; Gross, T P; Kaczmarek, R G; Hamilton, P; Hamburger, S

    1995-01-01

    Data on pacemaker implantation were obtained from the Medical Device Implant Supplement to the 1988 National Health Interview Survey, a nationally representative, population-based survey of 47,485 households (122,310 persons). The survey yielded an estimate of 456,482 noninstitutionalized adults with pacemakers (prevalence, 2.6 per 1,000). Prevalence rose significantly with age, from 0.4 per 1,000 among persons ages 18-64 to 26 per 1,000 among those ages 75 or older. Age-adjusted prevalence in males was 1.5 times that in females, and in whites 1.6 times that in nonwhites, although these differences were of borderline statistical significance. Prevalence did not vary significantly by region of residence, educational level, or income, but was significantly increased (more than threefold) in those reporting any activity limitation compared with those with no limitation. Fifteen percent of pacemakers in use were replacements; about one-fifth of these had been replaced more than twice. Sixty percent of previous pacemakers had been in place for at least 5 years. These data provide the first nationwide, population-based estimates of the epidemiology of pacemaker implantation, focusing particularly on the demographics of U.S. pacemaker recipients. PMID:7838942

  11. 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.

  12. [Slow activated voltage-dependent sodium current contribution in fast depolarization in the rabbit heart true pacemaker sinoatrial node].

    PubMed

    Golovko, V A

    2009-04-01

    The functional role of INa in initiation and conduction of cardiac true pacemaker activity remains uncertain. Therefore the goal of this work was to study the effects of Na+ substitution of action potentials parameters of the sinoatrial area cells. Transmembrane action potentials were recorded with 15 to 40 MOmega glass microelectrodes filled with 2.5 M KCl. The final preparations was about 5 x 3 mm in size, contained a portion sinoatrial node and the adjacent fragment of tissue of the right branch of the sinoatrial ring bundle and crista terminalis. All strips were allowed to beat spontaneously. We have registered that Na+ replacement of 50% in external solution causes an almost two-fold monotonous decrease of dV/dtmax and overshoot values of primary (3.2 V/s, n = 15), latent pacemaker (17 V/s, n = 16) and "conducting"-like cells (130 V/s, n = 16, control, 35 C) as compared with the control. Finally (at 30 min exposure) action potential frequency is slowed dowb by 20-30%. True pacemaker cells decreased action potential amplitude from 65 to 9 mV for 20-30 min 50% Na solution exposure. It should be noted that the cells of the "conducting"-like type demonstrated the generation block of action potential 30% Na exposure. At the same time dV/dtmax monotonously decreased from 3.1 to 1.5 V/s (true pacemaker) 16 vs 7 V/s (latent) and from 130 to 1.8 v/s ("conducting"). In our opinion, these facts deserve particular attention because it has been reported earlier that tetrodotoxin (20 mcM) addition in to the control solution caused the decrease of dV/dt from 100 to 4 V/s in latent pacemaker, whereas action potential amplitude is decreased by only some mV and the rate of beating by 1.5 times. As for true pacemaker cells, the TTX does not influence them.

  13. The role of out-of-hospital cardiac arrest in predicting hospital mortality for percutaneous coronary interventions in the Clinical Outcomes Assessment Program.

    PubMed

    Maynard, Charles; Rao, Sunil V; Gregg, Mary; Phillips, Richard C; Reisman, Mark; Tucker, Eben; Goss, J Richard

    2009-01-01

    Published mortality models for percutaneous coronary intervention (PCI), including the Clinical Outcomes Assessment Program (COAP) model, have not considered the effect of out-ofhospital cardiac arrest. The primary objective of this study was to determine if the inclusion of out-of-hospital cardiac arrest altered the COAP mortality model for PCI. The COAP PCI database contains extensive demographic, clinical, procedural and outcome information, including out-of-hospital cardiac arrest, which was added to the data collection form in 2006. This study included 15,586 consecutive PCIs performed in 31 Washington State hospitals in 2006. Using development and test sets, the existing COAP PCI logistic regression mortality model was examined to assess the effect of out-of-hospital arrest on in-hospital mortality. Overall, 2% of individuals undergoing PCI had cardiac arrest prior to hospital arrival. Among 8 hospitals with PCI volumes < 120 cases per year, 4 had cardiac arrest volumes that exceeded 10% of total volume, whereas none of the centers with > 120 cases per year did. In-hospital mortality was 19% in the arrest group and was 1.0% in remaining procedures (p < 0.0001). In the new multivariate model, out-of-hospital cardiac arrest was highly associated with mortality (odds ratio = 5.50; 95% confidence interval [CI] = 3.28-9.25). When evaluated in the test set, the new model had excellent discrimination (c-statistic = 0.89; 95% CI = 0.85-0.93). Out-of-hospital cardiac arrest is an important determinant of risk-adjusted in-hospital mortality for PCI, particularly for hospitals with low volumes and relatively high volumes of cardiac arrest cases.

  14. 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.

  15. Cardiac rehabilitation: a comprehensive program for the management of heart failure.

    PubMed

    Boudreau, Mary; Genovese, Janet

    2007-01-01

    Heart failure is one of the major health problems found in the United States today. Medical and interventional therapies play an important role in the treatment of this chronic condition, but they create a huge economic burden on the health care system. Nonpharmacologic interventions need further exploration. This article reviews research that examined the relationship between exercise and heart failure. A variety of exercise modalities measured outcomes of functional capacity and quality of life in both supervised and nonsupervised settings. Many investigators found exercise training to be safe and to confer benefits, especially on functional capacity, quality of life, and survival. The most favorable outcomes were observed in supervised settings. Cardiac rehabilitation provides an ideal environment for safe exercise and management of the health care needs of patients with heart failure. The multidisciplinary staff is adept at providing a paced approach to activity based on individualized exercise prescriptions, education, and management of this population's many comorbidities.

  16. Cardiobacterium hominis and Cardiobacterium valvarum: Two Case Stories with Infective Episodes in Pacemaker Treated Patients

    PubMed Central

    Bonavent, Tina Bennett; Nielsen, Xiaohui Chen; Kristensen, Kjeld Skødebjerg; Ihlemann, Nikolaj; Moser, Claus; Christensen, Jens Jørgen

    2016-01-01

    Introduction: Cardiobacterium hominis and Cardiobacterium valvarum are well known, though rare, etiologic agents of infective endocarditis. Cardiac devices are increasingly implanted. Case Reports: Two cases of infective episodes in pacemaker (PM) treated patients with respectively C. hominis and C. valvarum are presented. In one case blood-culture bottles yielded growth of C. hominis at two episodes with two years apart. At the second episode a vegetation was recognized at the PM lead and the PM device and lead was removed. In the C. valvarum case, echocardiography revealed a bicuspid aortic valve with severe regurgitation and a more than 1 cm sized vegetation. Conclusion: The cases illustrate the diversity in disease severity by Cardiobacterium species. Careful follow up has to be performed in order not to overlook a relatively silent relapsing infection. PMID:28077974

  17. Complete atrioventricular block in pregnancy: report of seven pregnancies in a patient without pacemaker

    PubMed Central

    Keepanasseril, Anish; Maurya, Dilip Kumar; J, Yavana Suriya; Selvaraj, Raja

    2015-01-01

    Obstetric management of a woman with a permanent pacemaker in situ is well reported in the literature; but those who present without pacing are still debatable. The necessity for setting the optimal timing or rate of temporary artificial pacing, specifically for labour, has not been objectively assessed. Temporary pacing in most cases reported in the literature might be to withstand the variations in haemodynamic status during delivery and labour. We report a case of a patient with complete heart block without any pacing who had seven pregnancies without any significant changes in haemodynamic status during labour and delivery. Managing a pregnancy without pacing might be an appropriate alternative for women without any underlying cardiac disorder, as it will not lead to significant changes in the haemodynamic system. PMID:25754166

  18. Long-term experience with a contractility (autonomic nervous system) driven pacemaker sensor in patients with chronic chagasic cardiomyopathy.

    PubMed

    Greco, Oswaldo Tadeu; Greco, Rafael Lois; Ardito, Roberto Vito

    2002-12-01

    We analyzed performance of a ventricle-paced, ventricle-sensed, inhibited, rate-responsive (VVIR) pacemaker driven by autonomic nervous system activity sensor in chagasic patients with cardiac conduction system disturbances. Forty-seven chagasic patients were studied (28 male, 19 female; age, 24-68 years). Thirty-six patients had complete atrioventricular (AV) block, eight had second-degree AV block, and the remaining three patients had sinus node disease. Patients were divided into two groups according to their heart rate (HR) at rest: group 1 had an HR more than 65 bpm; group 2, HR less than 65 bpm. A comparative study that extended over the first 12 months after pacemaker implantation evaluated: HR at rest and during various types of stress tests, arterial blood pressure at rest and during exercise, and performance of the TIR-60 UP leads in conjunction with the sensor function as compared with the performance of other leads. Patients from group 1 had a higher HR at rest and a smaller HR variation during stress test than did patients from group 2. This indicates that with this type of rate-adaptive system it is possible to control each patient individually. The blood pressure at rest and during stress tests did not differ between the two patient groups. With respect to the sensor function, the TIR-60 UP leads offered the same performance as others leads. The VVIR pacemaker equipped with the sensor of autonomic nervous system activity allowed chagasic patients to restore their physiologic mechanisms. Seventy-four percent of the patients had the New York Heart Association Functional Class improved by 1 or 2 steps, after the pacemaker implantation.

  19. Right Ventricular Anatomy Can Accommodate Multiple Micra Transcatheter Pacemakers

    PubMed Central

    EGGEN, MICHAEL D.; BONNER, MATTHEW D.; IAIZZO, PAUL A.; WIKA, KENT

    2016-01-01

    Background The introduction of transcatheter pacemaker technology has the potential to significantly reduce if not eliminate a number of complications associated with a traditional leaded pacing system. However, this technology raises new questions regarding how to manage the device at end of service, the number of devices the right ventricle (RV) can accommodate, and what patient age is appropriate for this therapy. In this study, six human cadaver hearts and one reanimated human heart (not deemed viable for transplant) were each implanted with three Micra devices in traditional pacing locations via fluoroscopic imaging. Methods A total of six human cadaver hearts were obtained from the University of Minnesota Anatomy Bequest Program; the seventh heart was a heart not deemed viable for transplant obtained from LifeSource and then reanimated using Visible Heart® methodologies. Each heart was implanted with multiple Micras using imaging and proper delivery tools; in these, the right ventricular volumes were measured and recorded. The hearts were subsequently dissected to view the right ventricular anatomies and the positions and spacing between devices. Results Multiple Micra devices could be placed in each heart in traditional, clinically accepted pacing implant locations within the RV and in each case without physical device interactions. This was true even in a human heart considered to be relatively small. Conclusions Although this technology is new, it was demonstrated here that within the human heart's RV, three Micra devices could be accommodated within traditional pacing locations: with the potential in some, for even more. PMID:26710918

  20. Pacemaker-Mediated Tachycardia: Manufacturer Specifics and Spectrum of Cases.

    PubMed

    Monteil, Benjamin; Ploux, Sylvain; Eschalier, Romain; Ritter, Philippe; Haissaguerre, Michel; Koneru, Jayanthi N; Ellenbogen, Kenneth A; Bordachar, Pierre

    2015-12-01

    Pacemaker-mediated tachycardia (PMT) is the term used to describe a repetitive sequence of sensed retrograde P waves followed by ventricular pacing at or below the maximum tracking rate. The following events can promote atrioventricular (AV) dissociation, retrograde conduction, and the onset of PMT: ventricular or atrial extrasystole, an excessively long programmed AV delay, external interference or myopotentials sensed by the atrial channel, atrial sensing or pacing failure, the absence of postventricular atrial refractory period extension after removal of a magnet, and VDD pacing at a higher rate than sinus rate. In contemporary devices, each manufacturer has a proprietary algorithm to detect and terminate PMT. Because of the increase in the number and complexity of the pacing algorithms and because of manufacturer-driven differences, a basic understanding of these new algorithms is important for patient care. We review here the main elements of the physiopathology of this type of tachycardia, describe the specific characteristics of the different manufacturers, and present representative clinical cases.

  1. 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.

  2. Atrioventricular nodal ablation versus antiarrhythmic drugs after permanent pacemaker implantation for bradycardia-tachycardia syndrome.

    PubMed

    Nagamoto, Yasutsugu; Inage, Tomohito; Yoshida, Teruhisa; Takeuchi, Tomohiro; Gondo, Takeki; Fukuda, Yujiro; Takii, Eiichi; Murotani, Kenta; Imaizumi, Tsutomu

    2012-03-01

    Patients often require antiarrhythmic drugs to control tachycardia after permanent pacemaker implantation (PMI) for bradycardia-tachycardia syndrome. We compared atrioventricular nodal ablation (AVNA) to antiarrhythmic drugs after PMI for bradycardia-tachycardia syndrome. Twenty-eight symptomatic patients with bradycardia-tachycardia syndrome, all of which had a long pause after termination of paroxysmal atrial fibrillation, underwent PMI with RV lead placement at the mid-septum site. Among these patients, 14 underwent PMI and AVNA (AVNA group). The remaining 14 patients underwent PMI only, and continued to take anti-arrhythmic drugs (drug group). We compared cardiac function (cardio-thoracic ratio on chest X-ray, left atrial diameter, left ventricular end-diastolic dimension, and left ventricular-ejection fraction by echocardiography), exercise tolerance (6-min walking distance), symptoms, and the number of antiarrhythmic drugs just before and 6 months after PMI. Baseline characteristics were similar between the two groups, except for the number of antiarrhythmic drugs. Six months after PMI, cardiac function, exercise tolerance, and symptoms did not differ significantly between the two groups. Compared to the drug group (p < 0.01), the number of antiarrhythmic drugs was significantly smaller in the AVNA group 6 months after PMI. Patients who underwent AVNA concurrently with PMI with RV lead placement at the mid-septum site for bradycardia-tachycardia syndrome were able to reduce the intake of drugs and improve their tachycardia-related symptoms while maintaining cardiac function and exercise tolerance.

  3. 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

  4. 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.

  5. Synergism of coupled subsarcolemmal Ca2+ clocks and sarcolemmal voltage clocks confers robust and flexible pacemaker function in a novel pacemaker cell model

    PubMed Central

    Maltsev, Victor A.; Lakatta, Edward G.

    2009-01-01

    Recent experimental studies have demonstrated that sinoatrial node cells (SANC) generate spontaneous, rhythmic, local subsarcolemmal Ca2+ releases (Ca2+ clock), which occur during late diastolic depolarization (DD) and interact with the classic sarcolemmal voltage oscillator (membrane clock) by activating Na+-Ca2+ exchanger current (INCX). This and other interactions between clocks, however, are not captured by existing essentially membrane-delimited cardiac pacemaker cell numerical models. Using wide-scale parametric analysis of classic formulations of membrane clock and Ca2+ cycling, we have constructed and initially explored a prototype rabbit SANC model featuring both clocks. Our coupled oscillator system exhibits greater robustness and flexibility than membrane clock operating alone. Rhythmic spontaneous Ca2+ releases of sarcoplasmic reticulum (SR)-based Ca2+ clock ignite rhythmic action potentials via late DD INCX over much broader ranges of membrane clock parameters [e.g., L-type Ca2+ current (ICaL) and/or hyperpolarization-activated (“funny”) current (If) conductances]. The system Ca2+ clock includes SR and sarcolemmal Ca2+ fluxes, which optimize cell Ca2+ balance to increase amplitudes of both SR Ca2+ release and late DD INCX as SR Ca2+ pumping rate increases, resulting in a broad pacemaker rate modulation (1.8–4.6 Hz). In contrast, the rate modulation range via membrane clock parameters is substantially smaller when Ca2+ clock is unchanged or lacking. When Ca2+ clock is disabled, the system parametric space for fail-safe SANC operation considerably shrinks: without rhythmic late DD INCX ignition signals membrane clock substantially slows, becomes dysrhythmic, or halts. In conclusion, the Ca2+ clock is a new critical dimension in SANC function. A synergism of the coupled function of Ca2+ and membrane clocks confers fail-safe SANC operation at greatly varying rates. PMID:19136600

  6. 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.

  7. 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.

  8. A common Shox2-Nkx2-5 antagonistic mechanism primes the pacemaker cell fate in the pulmonary vein myocardium and sinoatrial node.

    PubMed

    Ye, Wenduo; Wang, Jun; Song, Yingnan; Yu, Diankun; Sun, Cheng; Liu, Chao; Chen, Fading; Zhang, Yanding; Wang, Fen; Harvey, Richard P; Schrader, Laura; Martin, James F; Chen, YiPing

    2015-07-15

    In humans, atrial fibrillation is often triggered by ectopic pacemaking activity in the myocardium sleeves of the pulmonary vein (PV) and systemic venous return. The genetic programs that abnormally reinforce pacemaker properties at these sites and how this relates to normal sinoatrial node (SAN) development remain uncharacterized. It was noted previously that Nkx2-5, which is expressed in the PV myocardium and reinforces a chamber-like myocardial identity in the PV, is lacking in the SAN. Here we present evidence that in mice Shox2 antagonizes the transcriptional output of Nkx2-5 in the PV myocardium and in a functional Nkx2-5(+) domain within the SAN to determine cell fate. Shox2 deletion in the Nkx2-5(+) domain of the SAN caused sick sinus syndrome, associated with the loss of the pacemaker program. Explanted Shox2(+) cells from the embryonic PV myocardium exhibited pacemaker characteristics including node-like electrophysiological properties and the capability to pace surrounding Shox2(-) cells. Shox2 deletion led to Hcn4 ablation in the developing PV myocardium. Nkx2-5 hypomorphism rescued the requirement for Shox2 for the expression of genes essential for SAN development in Shox2 mutants. Similarly, the pacemaker-like phenotype induced in the PV myocardium in Nkx2-5 hypomorphs reverted back to a working myocardial phenotype when Shox2 was simultaneously deleted. A similar mechanism is also adopted in differentiated embryoid bodies. We found that Shox2 interacts with Nkx2-5 directly, and discovered a substantial genome-wide co-occupancy of Shox2, Nkx2-5 and Tbx5, further supporting a pivotal role for Shox2 in the core myogenic program orchestrating venous pole and pacemaker development.

  9. Cardiac magnetic resonance imaging: patient safety considerations.

    PubMed

    Giroletti, Elio; Corbucci, Giorgio

    Magnetic Resonance Imaging (MRI) is widely used in medicine. In cardiology, it is used to assess congenital or acquired diseases of the heat: and large vessels. Unless proper precautions are taken, it is generally advisable to avoid using this technique in patients with implanted electronic stimulators, such as pacemakers and defibrillators, on account of the potential risk of inducing electrical currents on the endocardial catheters, since these currents might stimulate the heart at a high frequency, thereby triggering dangerous arrhythmias. In addition to providing some basic information on pacemakers, defibrillators and MRI, and on the possible physical phenomena that may produce harmful effects, the present review examines the indications given in the literature, with particular reference to coronary stents, artificial heart valves and implantable cardiac stimulators.

  10. 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.

  11. Can course format influence the performance of students in an advanced cardiac life support (ACLS) program?

    PubMed

    Garrido, F D; Romano, M M D; Schmidt, A; Pazin-Filho, A

    2011-01-01

    Advanced cardiac life support (ACLS) is a problem-based course that employs simulation techniques to teach the standard management techniques of cardiovascular emergencies. Its structure is periodically revised according to new versions of the American Heart Association guidelines. Since it was introduced in Brazil in 1996, the ACLS has been through two conceptual and structural changes. Detailed documented reports on the effect of these changes on student performance are limited. The objective of the present study was to evaluate the effect of conceptual and structural changes of the course on student ACLS performance at a Brazilian training center. This was a retrospective study of 3266 students divided into two groups according to the teaching model: Model 1 (N = 1181; 1999-2003) and Model 2 (N = 2085; 2003-2007). Model 2 increased practical skill activities to 75% of the total versus 60% in Model 1. Furthermore, the teaching material provided to the students before the course was more objective than that used for Model 1. Scores greater than 85% in the theoretical evaluation and approval in the evaluation of practice by the instructor were considered to be a positive outcome. Multiple logistic regression was used to adjust for potential confounders (specialty, residency, study time, opportunity to enhance practical skills during the course and location where the course was given). Compared to Model 1, Model 2 presented odds ratios (OR) indicating better performance in the theoretical (OR = 1.34; 95%CI = 1.10-1.64), practical (OR = 1.19; 95%CI = 0.90-1.57), and combined (OR = 1.38; 95%CI = 1.13-1.68) outcomes. Increasing the time devoted to practical skills did not improve the performance of ACLS students.

  12. A coupled SYSTEM of intracellular Ca2+ clocks and surface membrane voltage clocks controls the timekeeping mechanism of the heart’s pacemaker

    PubMed Central

    Lakatta, Edward G.; Maltsev, Victor A.; Vinogradova, Tatiana M.

    2010-01-01

    Ion channels on the surface membrane of sinoatrial nodal pacemaker cells (SANC) are the proximal cause of an action potential. Each individual channel type has been thoroughly characterized under voltage clamp, and the ensemble of the ion channel currents reconstructed in silico generates rhythmic action potentials. Thus, this ensemble can be envisioned as a surface “membrane clock” (M clock). Localized subsarcolemmal Ca2+ releases are generated by the sarcoplasmic reticulum via ryanodine receptors during late diastolic depolarization and are referred to as an intracellular “Ca2+ clock”, because their spontaneous occurrence is periodic during voltage clamp or in detergent-permeabilized SANC, and in silico as well. In spontaneously firing SANC, the M and Ca2+ clocks do not operate in isolation, but work together via numerous interactions modulated by membrane voltage, subsarcolemmal Ca2+, and PKA and CaMKII-dependent protein phosphorylation. Through these interactions the two subsystem clocks become mutually entrained to form a robust, stable, coupled-clock system that drives normal cardiac pacemaker cell automaticity. G-protein coupled-receptors signaling creates pacemaker flexibility, i.e. effects changes in the rhythmic action potential firing rate, by impacting on these very same factors that regulate robust basal coupled-clock system function. This review examines evidence that forms the basis of this coupled-clock system concept in cardiac SANC. PMID:20203315

  13. Two pacing spikes on the QRS complex in a single-chamber pacemaker

    PubMed Central

    Choudhary, Dinesh; Sundaram, Shunmuga; Thajudeen, Anees; Namboodiri, Narayanan

    2012-01-01

    AutoCapture algorithm helps the pacemakers to automatically adjust output close to the pacing threshold. This algorithm monitors the evoked response signal of myocardial depolarization, and delivers a high output back-up pulse if there is a loss of capture. This case, with two pacemaker spikes on the QRS complexes in a patient with VVI pacemaker, simulating a sensing failure, demands clear understanding of AutoCapture function before labeling the pacemaker malfunction. PMID:23102397

  14. Positional convulsant syncope in a pacemaker patient following insulation break of the right ventricular lead

    PubMed Central

    Ben Lassoued, Mehdi; Baatour, Makram; Haggui, Abdeddayem; Lamine, Khaled

    2014-01-01

    In spite of the advances made in the technology of pacemakers which resulted in a decrease in the incidence of pacemaker lead fracture, the latter remains a potential complication of implanted pacemakers manufactured in the early days. In this report, we present a case of fracture of the unipolar electrode diagnosed by an emergency physician in a patient on a pacemaker for 10 years who presented to the emergency department with positional convulsant syncopes. PMID:24827652

  15. Pacemakers: some of the risks and complications you are not warned about.

    PubMed

    Marsh, Ann

    2008-10-01

    Pacemaker technology has advanced rapidly over the last decade. A lot of everyday interference can be regarded as transient. The media tend to cover stories of relatively insignificant transient interference incurred by pacemaker wearers while many manuals gloss over the high risks, some potentially life-threatening. These include the reliability of pacemakers and the use of monopolar diathermy which can generate electromagnetic interference, potentially causing a pacemaker to malfunction.

  16. 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…

  17. 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)

  18. Fetal programming alters reactive oxygen species production in sheep cardiac mitochondria.

    PubMed

    von Bergen, Nicholas H; Koppenhafer, Stacia L; Spitz, Douglas R; Volk, Kenneth A; Patel, Sonali S; Roghair, Robert D; Lamb, Fred S; Segar, Jeffrey L; Scholz, Thomas D

    2009-04-01

    Exposure to an adverse intrauterine environment is recognized as an important risk factor for the development of cardiovascular disease later in life. Although oxidative stress has been proposed as a mechanism for the fetal programming phenotype, the role of mitochondrial O(2)(*-) (superoxide radical) production has not been explored. To determine whether mitochondrial ROS (reactive oxygen species) production is altered by in utero programming, pregnant ewes were given a 48-h dexamethasone (dexamethasone-exposed, 0.28 mg.kg(-1) of body weight.day(-1)) or saline (control) infusion at 27-28 days gestation (term=145 days). Intact left ventricular mitochondria and freeze-thaw mitochondrial membranes were studied from offspring at 4-months of age. AmplexRed was used to measure H(2)O(2) production. Activities of the antioxidant enzymes Mn-SOD (manganese superoxide dismutase), GPx (glutathione peroxidase) and catalase were measured. Compared with controls, a significant increase in Complex I H(2)O(2) production was found in intact mitochondria from dexamethasone-exposed animals. The treatment differences in Complex I-driven H(2)O(2) production were not seen in mitochondrial membranes. Consistent changes in H(2)O(2) production from Complex III in programmed animals were not found. Despite the increase in H(2)O(2) production in intact mitochondria from programmed animals, dexamethasone exposure significantly increased mitochondrial catalase activity, whereas Mn-SOD and GPx activities were unchanged. The results of the present study point to an increase in the rate of release of H(2)O(2) from programmed mitochondria despite an increase in catalase activity. Greater mitochondrial H(2)O(2) release into the cell may play a role in the development of adult disease following exposure to an adverse intrauterine environment.

  19. 77 FR 37573 - Effective Date of Requirement for Premarket Approval for an Implantable Pacemaker Pulse Generator

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-22

    ... Approval for an Implantable Pacemaker Pulse Generator AGENCY: Food and Drug Administration, HHS. ACTION... protocol (PDP) for implantable pacemaker pulse generators. The Agency has summarized its findings regarding... PMA or notice of completion of a PDP for the implantable pacemaker pulse generator. In accordance...

  20. [Migration of an epicardial pacemaker into the abdominal cavity].

    PubMed

    Barabás, János Imre; Hüttl, Tivadar; Hartyánszky, István; Fazekas, Levente; Oláh, Zoltán; Zima, Endre; Paulovich, Erzsébet; Kőszegi, Andrea; Szabolcs, Zoltán

    2015-01-25

    Migration of a permanent pacemaker generator from their intramuscular pocket to the abdominal cavity is a less frequent, but potentially life-threatening complication. The authors present the case of a 69-year-old woman, who visited the emergency department of the clinic, with complains of non-specific abdominal symptoms. Her past medical history included a complete atrioventricular block diagnosed in 2009 during the mitral valve replacement and since then she had an epicardial permanent pacemaker; the pulse generator was placed into an intramuscular pouch created in the left subcostal region. Surprisingly, radiologic examinations showed that the generator migrated into the pouch of Douglas. Considering patient safety, first a new intracardiac pacemaker was implanted and then the migrated device was removed surgically. The patient was discharged on the seventh postoperative day.

  1. Ductal carcinoma of the breast in the pacemaker generator's pocket.

    PubMed

    Zonca, P; Herokova, J; Cambal, M; Jacobi, C A

    2009-01-01

    Authors present a case of a 78-year-old female patient with invasive ductal adenocarcinoma in the pacemaker, s pocket. A decubitus-like tumor had developed in this place, and has been missinterpretated as a benign lesion for 5 months. Diagnosis was done with a time delay. An excisional biopsy revealed annvasive ductal adenocarcinoma. The first step was the implantation of a new pacemaker generator performed on the opposite side. The second step was a modified radical mastectomy, according to Madden, and the removal of the originally implanted pacemaker generator. Radiotherapy and hormonal adjuvant therapy were applied after surgery. The patient was followed-up at an out-patient clinic, and died 25 months after diagnosis because of generalization of the disease (Fig. 2, Ref. 35). Full Text (Free, PDF) www.bmj.sk.

  2. Pacemaker Placement in Patients with Stroke-Mediated Autonomic Dysregulation

    PubMed Central

    Alsaad, Ali A.; Austin, Christopher O.; Robinson, Maisha T.

    2017-01-01

    Lateral medullary syndrome (LMS) is an ischemic disease of the medulla oblongata, which involves the territory of the posterior inferior cerebellar artery. Lateral medullary syndrome is often missed as the cause of autonomic dysregulation in patients with recent brain stem stroke. Due to the location of the baroreceptor regulatory center in the lateral medulla oblongata, patients with LMS occasionally have autonomic dysregulation-associated clinical manifestations. We report a case of LMS-associated autonomic dysregulation. The case presented as sinus arrest and syncope, requiring permanent pacemaker placement. A dual-chamber pacemaker was placed, after failure of conservative measures to alleviate the patient's symptoms. Our case shows the importance of recognizing LMS as a potential cause for life-threatening arrhythmias, heart block, and symptomatic bradycardia. Placement of permanent pacemaker may be necessary in some patients with LMS presenting with syncope, secondary to sinus arrest.

  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, Bárbara Maria; Cardoso, Dannuey Machado; Gomes, Tiago José Nardi; dos Santos, Tamires Daros; Vicente, Marília Severo; Pereira, Sérgio 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. PMID:27163422

  4. Dosimetry of portable image intensifiers in pacemaker insertions.

    PubMed

    Hayt, D B; Malsky, S J; Blatt, C J; Greenberg, E I; Pochaczevsky, R; Simon, D F; Perez, L A

    1975-01-01

    With the increased utilization of portable image intensifiers for pacemaker insertions, an investigation of the radiation hazards to operative personnel was undertaken. The personnel were tested first utilizing a Rando phantom and later during actual pacemaker insertions. Studies of medical personnel show the critical organs to be the thyroid (approximately 15mR per procedure) and the lens of the eye (approximately 13mR per procedure). While the MPD/week was not exceeded, the radiation dosage was substantial and could increase under operating conditions other than those measured. Recommendations to insure safer operation of this equipment are presented.

  5. Femoral approach: an exceptional alternative for permanent pacemaker implantation.

    PubMed

    Tereno Valente, Bruno; Conceição, José M; Nogueira da Silva, Manuel; M Oliveira, Mário; S Cunha, Pedro; Lousinha, Ana; Galrinho, Ana; C Ferreira, Rui

    2014-05-01

    The classic transvenous implantation of a permanent pacemaker in a pectoral location may be precluded by obstruction of venous access through the superior vena cava or recent infection at the implant site. When these barriers to the procedure are bilateral and there are also contraindications or technical difficulties to performing a thoracotomy for an epicardial approach, the femoral vein, although rarely used, can be a viable alternative. We describe the case of a patient with occlusion of both subclavian veins and a high risk for mini-thoracotomy or videothoracoscopy, who underwent implantation of a permanent single-chamber pacemaker via the right femoral vein.

  6. Lead or be led: an update on leadless cardiac devices for general physicians.

    PubMed

    Wiles, Benedict M; Roberts, Paul R

    2017-02-01

    Implantable cardiac devices have an increasingly important role. Pacemakers remain the only effective treatment for symptomatic bradycardia; cardiac resynchronisation therapy is a proven treatment for heart failure; and implantable cardioverter defibrillators (ICD) are superior to medical therapy in prevention of sudden cardiac death. Our ageing population has led to a rising number of device implants. Physicians in all specialties increasingly encounter patients with cardiac devices and require an understanding of their capabilities and functions. The rising prevalence of implantable devices has been matched by a parallel expanse in device technology. Leadless devices have become a reality and represent the future of device therapy. The absence of a transvenous lead offers a significant clinical advantage because of many well established issues related to lead complications. The leadless pacemaker and subcutaneous ICD are significant new products that are currently not well recognised or understood by general physicians.

  7. Respiration as a reliable physiological sensor for controlling cardiac pacing rate.

    PubMed

    Rossi, P; Plicchi, G; Canducci, G; Rognoni, G; Aina, F

    1984-01-01

    A study was carried out to determine whether variations in the respiration rate during physical exercise could be used as a physiological variable in controlling the rate of an implanted pacemaker. The relation between respiration rate and heart rate was significantly correlated in 73 patients (19 with normal lung function, four with restrictive pulmonary disease, and 50 with obstructive airways disease) during repeated calibrated ergometric tests; no significant differences were found between the subgroups. An external computerised programmable system with algorithm control activated by a radio frequency system was used to vary the cardiac stimulation rate in relation to respiration rate in 11 patients implanted with ventricular inhibited pacemakers. In addition, a prototype programmable pacemaker dependent on respiration rate was implanted in two patients. Maximum values of oxygen uptake, minute ventilation, and work time were increased during the exercise stress tests when the variable cardiac pacing rate was used. Thus respiration rate appears to be a valid and stable physiological variable for controlling the cardiac stimulation rate in order to improve cardiac output in patients dependent on pacemakers.

  8. Electromagnetic interference of implantable cardiac devices from a shoulder massage machine.

    PubMed

    Yoshida, Saeko; Fujiwara, Kousaku; Kohira, Satoshi; Hirose, Minoru

    2014-09-01

    Shoulder massage machines have two pads that are driven by solenoid coils to perform a per cussive massage on the shoulders. There have been concerns that such machines might create electromagnetic interference (EMI) in implantable cardiac devices because of the time-varying magnetic fields produced by the alternating current in the solenoid coils. The objective of this study was to investigate the potential EMI from one such shoulder massage machine on implantable cardiac devices. We measured the distribution profile of the magnetic field intensity around the massage machine. Furthermore, we performed an inhibition test and an asynchronous test on an implantable cardiac pacemaker using the standardized Irnich human body model. We examined the events on an implantable cardioverter-defibrillator (ICD) using a pacemaker programmer while the massage machine was in operation. The magnetic field distribution profile exhibited a peak intensity of 212 (A/m) in one of the solenoid coils. The maximal interference distance between the massage machine and the implantable cardiac pacemaker was 28 cm. Ventricular fibrillation was induced when the massage machine was brought near the electrode of the ICD and touched the Irnich human body model. It is necessary to provide a "don't use" warning on the box or the exterior of the massage machines or in the user manuals and to caution patients with implanted pacemakers about the dangers and appropriate usage of massage machines.

  9. 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

  10. Cardiac catheterization - discharge

    MedlinePlus

    Catheterization - cardiac - discharge; Heart catheterization - discharge: Catheterization - cardiac; Heart catheterization; Angina - cardiac catheterization discharge; CAD - cardiac catheterization discharge; Coronary artery disease - cardiac catheterization ...

  11. FDG PET/CT Evidence of Effective Treatment of Cardiac Sarcoidosis With Adalimumab.

    PubMed

    Miller, Christina T; Sweiss, Nadera J; Lu, Yang

    2016-05-01

    A 53-year-old man with mediastinal lymph node biopsy and cardiac MRI-proven cardiac sarcoidosis (CS) received treatment with pacemaker and steroids. FDG PET/CT showed active CS despite treatment with prednisone and methotrexate. Addition of weekly adalimumab (Humira) injections was introduced for 3 months. Follow-up FDG PET/CT showed complete resolution of CS as well as improvement of other sarcoid lesions in the thoracic lymph nodes.

  12. P wave and far-field R wave detection in pacemaker patient atrial electrograms.

    PubMed

    Theres, H; Sun, W; Combs, W; Panken, E; Mead, H; Baumann, G; Stangl, K

    2000-04-01

    This study was undertaken to develop and test a morphology-based adaptive algorithm for real-time detection of P waves and far-field R waves (FFRWs) in pacemaker patient atrial electrograms. Cardiac event discrimination in right atrial electrograms has been a problem resulting in improper atrial sensing in implantable devices; potentially requiring clinical evaluation and device reprogramming. A morphology-based adaptive algorithm was first evaluated with electrograms recorded from 25 dual chamber pacemaker implant patients. A digital signal processing (DSP) system was designed to implement the algorithm and test real-time detection. In the second phase, the DSP implementation was evaluated in 13 patients. Atrial and ventricular electrograms were processed in real-time following algorithm training performed in the first few seconds for each patient. Electrograms were later manually annotated for comparative analysis. The sensitivity for FFRW detection in the atrial electrogram during off-line analysis was 92.5% (+/- 10.9) and the positive predictive value was 99.1% (+/- 1.8). Real-time P wave detection using a DSP system had a sensitivity of 98.9% (+/- 1.3) and a positive predictivity of 97.3% (+/- 3.5). FFRW detection had a sensitivity of 91.0% (+/- 12.4) and a positive predictivity of 97.1% (+/- 4.2) in atrial electrograms. DSP algorithm tested can accurately detect both P waves and FFRWs in right atrium real-time. Advanced signal processing techniques can be applied to arrhythmia detection and may eventually improve detection, reduce clinician interventions, and improve unipolar and bipolar lead sensing.

  13. 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... asynchronous modes and is implanted in the human body. (b) Classification. Class III (premarket approval)....

  14. 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... required to be filed with the Food and Drug Administration on or before November 21, 2011, for...

  15. [Aspergillus fumigatus endocarditis in a patient with a biventricular pacemaker].

    PubMed

    Cuesta, José M; Fariñas, María C; Rodilla, Irene G; Salesa, Ricardo; de Berrazueta, José R

    2005-05-01

    Aspergillus fumigatus endocarditis is one of the rarest and severest complications in cardiological patients. We describe a patient with an intracardial pacemaker who was diagnosed as having Aspergillus fumigatus endocarditis. Postmortem examination showed a large, Aspergillus-infected thrombus encased in the right ventricle, pulmonary trunk and main pulmonary branches.

  16. Un Corazón Saludable: factors influencing outcomes of an exercise program designed to impact cardiac and metabolic risks among urban Latinas.

    PubMed

    Harralson, Tina L; Emig, Julie Cousler; Polansky, Marcia; Walker, Renee E; Cruz, Joanna Otero; Garcia-Leeds, Claudia

    2007-12-01

    A high prevalence of physical inactivity, metabolic risk factors, and depression place Latinas in peril of developing cardiovascular disease. "Un Corazón Saludable: A Healthy Heart" was developed to engage urban Latinas in physical activity and increase awareness of cardiac and metabolic risk factors. Two hundred and twenty-five Latinas enrolled in the program that included salsa aerobics and culturally sensitive health education modules. Cardiac and metabolic risk factors measured in this study were body mass index (BMI), waist-to-hip ratio, abdominal obesity, and blood pressure. Psychosocial risk factors measured included depressive symptoms and perceived social support. Fifty-two percent of the enrollees completed the program. Results indicated decreases in BMI, abdominal obesity, and symptoms of depression among Latinas who completed the program. Those who did not complete the program were younger, had greater depressive symptomatology, reported poorer social support, and they tended to be caregivers and U.S. born. Focus groups of program participants ascertained that caregiving and family obligations were major barriers to exercise while social support was a major facilitator of exercise. This research indicates that programs developed to recognize and address cultural barriers can impact physical and psychosocial risk factors among urban Latinas who are able to attend. Program retention may improve if future exercise programs conducted through community-base organizations offered support to Latinas regarding issues that interfere with self-care and health promotion. Future programs should consider including mental health and social service case management as part of comprehensive exercise/educational programs.

  17. Individual-, family-, community-, and policy-level impact of a school-based cardiovascular risk detection screening program for children in underserved, rural areas: the CARDIAC Project.

    PubMed

    Cottrell, Lesley; John, Collin; Murphy, Emily; Lilly, Christa L; Ritchie, Susan K; Elliott, Eloise; Minor, Valerie; Neal, William A

    2013-01-01

    The Coronary Artery Risk Detection In Appalachian Communities (CARDIAC) Project has screened more than 80,000 children (10-12 years) for cardiovascular and diabetes risk factors over the past 15 years. Simultaneous referral and intervention efforts have also contributed to the overall program impact. In this study, we examined evidence of programmatic impact in the past decade at the individual, family, community, and policy levels from child screening outcomes, referral rates, participation in subsequent services, and policies that embed the activities of the project as a significant element. Within this period of time, fifth-grade overweight and obesity rates were maintained at a time when rates elsewhere increased. 107 children were referred for additional screening and treatment for probable familial hypercholesterolemia (FH); 82 family members were subsequently screened in family-based screening efforts. 58 grants were distributed throughout the state for community-appropriate obesity intervention. A state wellness policy embedded CARDIAC as the method of assessment and national child cholesterol screening guidelines were impacted by CARDIAC findings. The sustainability and successful impact of this school-based program within a largely underserved, rural Appalachian state are also discussed.

  18. The surdo-cardiac syndrome and therapeutic observations

    PubMed Central

    Olley, P. M.; Fowler, R. S.

    1970-01-01

    First recognized in 1957, the surdo-cardiac syndrome includes congenital deafness, prolonged QT interval, and a high incidence of syncope and sudden death. Haemodynamic studies in two patients were normal except for an abnormal wave during left ventricular diastole probably related to abnormal left ventricular relaxation. The syncopal attacks are based on cardiac arrhythmias: both ventricular fibrillation and asystole may occur. Abnormal adrenergic stimulation of the heart is probably responsible. Propranolol appears to be effective in preventing the syncopal attacks. Artificial pacemaking provoked ventricular fibrillation in one patient and seems contraindicated. Images PMID:5433307

  19. Combined use of non-thoracotomy cardioverter defibrillators and endocardial pacemakers.

    PubMed Central

    Noguera, H. H.; Peralta, A. O.; John, R. M.; Venditti, F. J.; Martin, D. T.

    1997-01-01

    OBJECTIVE: To study the potential interactions in patients with endocardial permanent pacemakers and non-thoracotomy implantable cardioverter defibrillator (ICD) systems. DESIGN: Case series and cohort study. SETTING: Tertiary referral centre. PATIENTS: Fifteen consecutive patients with both endocardial pacemakers (12 dual chamber and three single chamber) and non-thoracotomy ICD systems. MAIN OUTCOME MEASURES: Detection inhibition of induced ventricular fibrillation; double counting; and pacemaker function after shocks. In the evaluation of detection inhibition, 124 VF inductions were analysed for detection duration compared with induced VF episodes in controls with an ICD but without a pacemaker. RESULTS: Two patients (13%) showed detection inhibition of VF and required pacemaker system change at the time of the ICD implant. With the final lead position, despite frequent pacemaker undersensing of VF, ICD detection of VF was not inhibited during any induction, and neither initial detection nor redetection times for VF were different from controls. Double/triple counting of pacemaker artefact and evoked electrogram was noted in three patients (20%). In two, this was remedied during the implantation procedure, and in the other it was abolished when amiodarone treatment was discontinued. Pacemaker function was affected by ICD discharges in two patients, one who showed postshock atrial undersensing and loss of capture, and another whose pacemaker reverted to VVI mode. CONCLUSIONS: When careful testing is performed at implantation to detect and remedy device interactions, non-thoracotomy ICD treatment and endocardial pacemakers can be used safely in combination. Images PMID:9290402

  20. Safety of magnetic resonance imaging in patients with implanted cardiac prostheses and metallic cardiovascular electronic devices.

    PubMed

    Baikoussis, Nikolaos G; Apostolakis, Efstratios; Papakonstantinou, Nikolaos A; Sarantitis, Ioannis; Dougenis, Dimitrios

    2011-06-01

    Magnetic resonance imaging (MRI) in patients with implanted cardiac prostheses and metallic cardiovascular electronic devices is sometimes a risky procedure. Thus MRI in these patients should be performed when it is the only examination able to help with the diagnosis. Moreover the diagnostic benefit must outweigh the risks. Coronary artery stents, prosthetic cardiac valves, metal sternal sutures, mediastinal vascular clips, and epicardial pacing wires are not contraindications for MRI, in contrast to pacemakers and implantable cardioverter-defibrillators. Appropriate patient selection and precautions ensure MRI safety. However it is commonly accepted that although hundreds of patients with pacemakers or implantable cardioverter-defibrillators have undergone safe MRI scanning, it is not a safe procedure. Currently, heating of the pacemaker lead is the major problem undermining MRI safety. According to the US Food and Drug Administration (FDA), there are currently neither "MRI-safe" nor "MRI-compatible" pacemakers and implantable cardioverter-defibrillators. In this article we review the international literature in regard to safety during MRI of patients with implanted cardiac prostheses and metallic cardiovascular electronic devices.

  1. Risk of electromagnetic interference induced by dental equipment on cardiac implantable electrical devices.

    PubMed

    Miranda-Rius, Jaume; Lahor-Soler, Eduard; Brunet-Llobet, Lluís; Sabaté de la Cruz, Xavier

    2016-12-01

    Patients with cardiac implantable electrical devices should take special precautions when exposed to electromagnetic fields. Proximity to equipment used in clinical dentistry may cause interference. This study evaluated in vitro the risks associated with different types/makes of cardiac devices and types of dental equipment. Six electronic dental tools were tested on three implantable cardioverter defibrillators and three pacemakers made by different manufacturers. Overall, the risk of interference with the pacemakers was 37% lower than with the implantable cardioverter defibrillators. Regarding the types/makes of cardiac devices analysed, that from Boston Scientific had a five-fold greater risk of interference than did that from Biotronik [prevalence ratio (PR) = 5.58]; there was no difference between that from Biotronik and that from Medtronic. Among the dental equipment, the electric pulp tester had the greatest risk of inducing interference and therefore this device was used as the benchmark. The electronic apex locator (PR = 0.29), Periotest M (PR = 0.47), and the ultrasonic dental scaler (PR = 0.59) were less likely to induce interference than the electric pulp tester. The risk was lowest with the electronic apex locator. Pacemakers presented a lower risk of light to moderate interference (PR = 0.63). However, the risk of severe electromagnetic interference was 3.5 times higher with pacemakers than with implantable cardioverter defibrillators (PR = 3.47).

  2. The role of acute hyperinsulinemia in the development of cardiac arrhythmias.

    PubMed

    Drimba, László; Döbrönte, Róbert; Hegedüs, Csaba; Sári, Réka; Di, Yin; Németh, Joseph; Szilvássy, Zoltán; Peitl, Barna

    2013-05-01

    Patients with perturbed metabolic control are more prone to develop cardiac rhythm disturbances. The main purpose of the present preclinical study was to investigate the possible role of euglycemic hyperinsulinemia in development of cardiac arrhythmias. Euglycemic hyperinsulinemia was induced in conscious rabbits equipped with a right ventricular pacemaker electrode catheter by hyperinsulinemic euglycemic glucose clamp (HEGC) applying two different rates of insulin infusion (5 and 10 mIU/kg/min) and variable rate of glucose infusion to maintain euglycemia (5.5 ± 0.5 mmol/l). The effect of hyperinsulinemia on cardiac electrophysiological parameters was continuously monitored by means of 12-lead surface ECG recording. Arrhythmia incidence was determined by means of programmed electrical stimulation (PES). The possible role of adrenergic activation was investigated by determination of plasma catecholamine levels and intravenous administration of a beta adrenergic blocking agent, metoprolol. All of the measurements were performed during the steady-state period of HEGC and subsequent to metoprolol administration. Both 5 and 10 mIU/kg/min insulin infusion prolonged significantly QTend, QTc, and Tpeak-Tend intervals. The incidence of ventricular arrhythmias generated by PES was increased significantly by euglycemic hyperinsulinemia and exhibited linear relationship to plasma levels of insulin. No alteration on plasma catecholamine levels could be observed; however, metoprolol treatment restored the prolonged QTend, QTc, and Tpeak-Tend intervals and significantly reduced the hyperinsulinemia-induced increase of arrhythmia incidence. Euglycemic hyperinsulinemia can exert proarrhythmic effect presumably due to the enhancement of transmural dispersion of repolarization. Metoprolol treatment may be of benefit in hyperinsulinemia associated with increased incidence of cardiac arrhythmias.

  3. 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.

  4. Canadian Cardiovascular Society/Canadian Anesthesiologists' Society/Canadian Heart Rhythm Society joint position statement on the perioperative management of patients with implanted pacemakers, defibrillators, and neurostimulating devices.

    PubMed

    Healey, Jeff S; Merchant, Richard; Simpson, Chris; Tang, Timothy; Beardsall, Marianne; Tung, Stanley; Fraser, Jennifer A; Long, Laurene; van Vlymen, Janet M; Manninen, Pirjo; Ralley, Fiona; Venkatraghavan, Lashmi; Yee, Raymond; Prasloski, Bruce; Sanatani, Shubhayan; Philippon, François

    2012-01-01

    There are more than 200,000 Canadians living with permanent pacemakers or implantable defibrillators, many of whom will require surgery or invasive procedures each year. They face potential hazards when undergoing surgery; however, with appropriate planning and education of operating room personnel, adverse device-related outcomes should be rare. This joint position statement from the Canadian Cardiovascular Society (CCS) and the Canadian Anesthesiologists' Society (CAS) has been developed as an accessible reference for physicians and surgeons, providing an overview of the key issues for the preoperative, intraoperative, and postoperative care of these patients. The document summarizes the limited published literature in this field, but for most issues, relies heavily on the experience of the cardiologists and anesthesiologists who contributed to this work. This position statement outlines how to obtain information about an individual's type of pacemaker or implantable defibrillator and its programming. It also stresses the importance of determining if a patient is highly pacemaker-dependent and proposes a simple approach for nonelective evaluation of dependency. Although the document provides a comprehensive list of the intraoperative issues facing these patients, there is a focus on electromagnetic interference resulting from electrocautery and practical guidance is given regarding the characteristics of surgery, electrocautery, pacemakers, and defibrillators which are most likely to lead to interference. The document stresses the importance of preoperative consultation and planning to minimize complications. It reviews the relative merits of intraoperative magnet use vs reprogramming of devices and gives examples of situations where one or the other approach is preferable.

  5. A noninvasive method for locating a cardiac dipolar source in humans.

    PubMed

    Salu, Y; Bischof, C; Pandian, N

    1982-01-01

    A noninvasive method for locating isolated areas of cardiac electrical activity, such as an ectopic focus, is introduced and evaluated. Surface electric potentials due to the source are recorded at 20-25 points on the chest. Each chest is measured and its configuration is approximated by a grid of 126 points. A computer program utilizes these data to calculate the x, y, z coordinates of the cardiac source, and this calculated location is displayed on the bi-plane chest x-rays of the patient. Errors that may occur in other methods that utilize average torso shape and average heart position are eliminated in the proposed method. The method was evaluated by using it for locating the electrodes of implanted pacemakers from their "spikes" in the ECG's, and also from the potentials at the onset of the induced QRS complexes. The results were compared with bi-plane x-rays of the same patients. It was found that the average errors in locating the electrodes from their "spikes" in the ECG's were 1.3 cm in the frontal view and 1.4 cm in the lateral view. The errors in locating the paced myocardial area at the beginning of the QRS complex were similar. The errors in the lateral view are systematic and may be attributed to the effects of the intracavity blood volume (Brody's effect), which are neglected in this method.

  6. Tricuspid-valve repair for pacemaker leads endocarditis.

    PubMed

    Iezzi, Federica; Cini, Roberto; Sordini, Paolo

    2010-12-20

    In non-addicted patients, several states, such as permanent pacemakers, can provide the predisposing factors for tricuspid-valve endocarditis. In this report, we present a case of a 66-year-old man with pacemaker lead infection and tricuspid-native-valve endocarditis, related to Staphylococcus hominis, very rare cause of infective endocarditis that carries a high-mortality risk. Surgery was indicated for the patient due to persistent enlarging vegetation on the tricuspid valve, severe tricuspid regurgitation, septic pulmonary emboli and finally uncompensated respiratory and heart failure. Many ingenious methods have been devised to repair the tricuspid valve in patients with infective endocarditis. Valve replacement, however, is hazardous due to the possibility of prosthetic infection, and we choose to repair the native valve. The patient has now been weel for 3 years.

  7. Transient apical dyskinesia with a pacemaker: Electrocardiographic features.

    PubMed

    Núñez-Gil, Iván J; Feltes, Gisela I; Mejía-Rentería, Hernán D; Biagioni, Corina; De Agustín, J Alberto; Vivas, David; Fernández-Ortiz, Antonio

    2015-04-01

    Transient apical dyskinesia syndromes present features similar to acute coronary syndromes, but with normal coronary arteries and rapid complete resolution of wall motion alterations. We report the case of a 73-year-old woman who was admitted to hospital because of typical chest pain at rest after her brother's death. She had had a pacemaker implanted in 2001. Troponin levels were elevated and apical hypokinesia was shown by ventriculography and echocardiography, with normal coronary arteries. Evolving ECG alterations were observed in spite of the continued pacing rhythm. All these alterations were fully resolved after discharge. This case shows that, even in the presence of a pacemaker, evolving ECG alterations can be observed in Takotsubo syndrome.

  8. 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

  9. 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

  10. 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

  11. Gold-coated pacemaker implantation for a patient with type IV allergy to titanium

    PubMed Central

    Kypta, Alexander; Blessberger, Hermann; Lichtenauer, Michael; Lambert, Thomas; Kammler, Juergen; Steinwender, Clemens

    2016-01-01

    A 65-year-old man was scheduled for pacemaker implantation for symptomatic sick-sinus-syndrome (SSS). He suffered from multiple drug-allergies and allergies to several metals like quicksilver and titanium. Gold-coated pacemaker generators and polyurethane leads are effective in avoiding allergic reactions to pacing system components. Therefore, we decided to implant a custom-made gold-coated DDDR-pacemaker generator and polyurethane leads. PMID:27479204

  12. 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.

  13. Isolating Neural Correlates of the Pacemaker for Food Anticipation

    PubMed Central

    Blum, Ian David; Waddington Lamont, Elaine; Rodrigues, Trevor; Abizaid, Alfonso

    2012-01-01

    Mice fed a single daily meal at intervals within the circadian range exhibit food anticipatory activity. Previous investigations strongly suggest that this behaviour is regulated by a circadian pacemaker entrained to the timing of fasting/refeeding. The neural correlate(s) of this pacemaker, the food entrainable oscillator (FEO), whether found in a neural network or a single locus, remain unknown. This study used a canonical property of circadian pacemakers, the ability to continue oscillating after removal of the entraining stimulus, to isolate activation within the neural correlates of food entrainable oscillator from all other mechanisms driving food anticipatory activity. It was hypothesized that continued anticipatory activation of central nuclei, after restricted feeding and a return to ad libitum feeding, would elucidate a neural representation of the signaling circuits responsible for the timekeeping component of the food entrainable oscillator. Animals were entrained to a temporally constrained meal then placed back on ad libitum feeding for several days until food anticipatory activity was abolished. Activation of nuclei throughout the brain was quantified using stereological analysis of c-FOS expressing cells and compared against both ad libitum fed and food entrained controls. Several hypothalamic and brainstem nuclei remained activated at the previous time of food anticipation, implicating them in the timekeeping mechanism necessary to track previous meal presentation. This study also provides a proof of concept for an experimental paradigm useful to further investigate the anatomical and molecular substrates of the FEO. PMID:22558352

  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. [Intermittent focal cerebral ischemia in hypotension due to pacemaker syndrome].

    PubMed

    Hagendorff, A; Pizzulli, L; Dettmers, C; Block, A; Omran, H; Hartmann, A; Manz, M; Lüderitz, B

    1994-12-01

    A pacemaker syndrome manifested as transient sensoric aphasia in a 68-year-old woman with a VVI-pace-maker implanted after SA-block. The attack occurred during long-term blood pressure recording and Holter monitoring. Borderline hypotension was documented during ventricular pacing which induced a retrograde excitation of the atrium. Clinical investigations excluded any intracranial abnormality, any source of embolism or stenosis of extra- and intracranial cerebral arteries. Cerebral blood flow measurements revealed a significant increase during pacing at elevated heart rate. Therefore, a device for AV-sequential pacing was implanted and basic pacing rate was elevated. The present case report indicates that focal and not only global cerebral ischemia can be produced by an impairment of systemic hemodynamics due to hypotension and a pacemaker syndrome. Improvement of cerebral blood flow during pacing is an unexpected finding contrasting with the concept of autoregulation. In addition, pacemaker implantation should be discussed in patients with transient cerebral perfusion deficits if an improvement of cerebral blood flow is documented along with rising heart rate.

  16. Predicting the risk of sudden cardiac death.

    PubMed

    Lerma, Claudia; Glass, Leon

    2016-05-01

    Sudden cardiac death (SCD) is the result of a change of cardiac activity from normal (typically sinus) rhythm to a rhythm that does not pump adequate blood to the brain. The most common rhythms leading to SCD are ventricular tachycardia (VT) or ventricular fibrillation (VF). These result from an accelerated ventricular pacemaker or ventricular reentrant waves. Despite significant efforts to develop accurate predictors for the risk of SCD, current methods for risk stratification still need to be improved. In this article we briefly review current approaches to risk stratification. Then we discuss the mathematical basis for dynamical transitions (called bifurcations) that may lead to VT and VF. One mechanism for transition to VT or VF involves a perturbation by a premature ventricular complex (PVC) during sinus rhythm. We describe the main mechanisms of PVCs (reentry, independent pacemakers and abnormal depolarizations). An emerging approach to risk stratification for SCD involves the development of individualized dynamical models of a patient based on measured anatomy and physiology. Careful analysis and modelling of dynamics of ventricular arrhythmia on an individual basis will be essential in order to improve risk stratification for SCD and to lay a foundation for personalized (precision) medicine in cardiology.

  17. TBX18 gene induces adipose-derived stem cells to differentiate into pacemaker-like cells in the myocardial microenvironment

    PubMed Central

    Yang, Mei; Zhang, Ge-Ge; Wang, Teng; Wang, Xi; Tang, Yan-Hong; Huang, He; Barajas-Martinez, Hector; Hu, Dan; Huang, Cong-Xin

    2016-01-01

    T-box 18 (TBX18) plays a crucial role in the formation and development of the head of the sinoatrial node. The objective of this study was to induce adipose-derived stem cells (ADSCs) to produce pacemaker-like cells by transfection with the TBX18 gene. A recombinant adenovirus vector carrying the human TBX18 gene was constructed to transfect ADSCs. The ADSCs transfected with TBX18 were considered the TBX18-ADSCs. The control group was the GFP-ADSCs. The transfected cells were co-cultured with neonatal rat ventricular cardiomyocytes (NRVMs). The results showed that the mRNA expression of TBX18 in TBX18-ADSCs was significantly higher than in the control group after 48 h and 7 days. After 7 days of co-culturing with NRVMs, there was no significant difference in the expression of the myocardial marker cardiac troponin I (cTnI) between the two groups. RT-qPCR and western blot analysis showed that the expression of HCN4 was higher in the TBX18-ADSCs than in the GFP-ADSCs. The If current was detected using the whole cell patch clamp technique and was blocked by the specific blocker CsCl. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSCMs) showed approximately twice the current density compared with the ADSCs. Our study indicated that the TBX18 gene induces ADSCs to differentiate into pacemaker-like cells in the cardiac microenvironment. Although further experiments are required in order to assess safety and efficacy prior to implementation in clinical practice, this technique may provide new avenues for the clinical therapy of bradycardia. PMID:27632938

  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. Permanent pacemaker lead induced severe tricuspid regurgitation in patient undergoing multiple valve surgery.

    PubMed

    Lee, Jung Hee; Kim, Tae Ho; Kim, Wook Sung

    2015-04-01

    Severe and permanent tricuspid regurgitation induced by pacemaker leads is rarely reported in the literature. The mechanism of pacemaker-induced tricuspid regurgitation has been identified, but its management has not been well established. Furthermore, debate still exists regarding the proper surgical approach. We present the case of a patient with severe tricuspid regurgitation induced by a pacemaker lead, accompanied by triple valve disease. The patient underwent double valve replacement and tricuspid valve repair without removal of the pre-existing pacemaker lead. The operation was successful and the surgical procedure is discussed in detail.

  20. Successful Interventional Management for Pulmonary Arterial Injury Secondary to Pacemaker Implantation

    PubMed Central

    Tokue, Azusa; Morita, Hideo; Tsushima, Yoshito

    2016-01-01

    Subclavian vein puncture is a relatively fast and safe technique to access the right heart for placement of pacemaker leads. Hemothorax related to injury of the pulmonary artery (PA) is a rare complication of subclavian vein access but can be life-threatening. We report a case of hemothorax occurring after subclavian vein puncture for pacemaker implantation. No cases of transcatheter arterial embolization for PA injury secondary to pacemaker implantation have been reported. Understanding of this rare complication after pacemaker implantation along with its specific clinical presentation may lead to early diagnosis and intervention. PMID:27882248

  1. 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…

  2. 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,…

  3. 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,…

  4. 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,…

  5. 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.

  6. Autonomic cardiac innervation: development and adult plasticity.

    PubMed

    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

  7. The Prevalence and Contents of Advance Directives in Patients With Pacemakers

    PubMed Central

    Pasalic, Dario; Tajouri, Tanya H.; Ottenberg, Abigale L.; Mueller, Paul S.

    2013-01-01

    Background Little is known about the use of advance directives (ADs) in patients who have implantable cardiac pacemakers (PMs). Methods We conducted a retrospective review of the medical records of residents of Olmsted County, Minnesota, who underwent implantation of a cardiac PM at Mayo Clinic (Rochester, Minnesota) during 2006 and 2007 and determined the prevalence and contents of ADs in these patients. Results During the study period, 205 residents of Olmsted County (men, 53%) underwent PM implantation (mean age [SD] at implantation, 77 [15] years). Overall, 120 patients (59%) had ADs. Of these, 63 ADs (53%) were executed more than 12 months before and 33 (28%) were executed after PM implantation. Many patients specifically mentioned life-prolonging treatments in their ADs: cardiopulmonary resuscitation, 76 (63%); mechanical ventilation, 56 (47%); and hemodialysis, 31 (26%). Pain control was mentioned in 79 ADs (66%) and comfort measures were mentioned in 42 ADs (35%). Furthermore, the AD of many patients contained a general statement about end-of-life care (eg, no “heroic measures”). However, only 1 AD (1%) specifically addressed the end-of-life management of the PM. Conclusions More than half of the patients with PMs in our study had executed an AD, but only 1 patient specifically mentioned her PM in her AD. These results suggest that patients with PMs should be encouraged to execute ADs and, specifically address end-of-life device management in their ADs. Doing so may prevent end-of-life ethical dilemmas related to PM management. PMID:24215172

  8. SU-E-T-169: Characterization of Pacemaker/ICD Dose in SAVI HDR Brachytherapy

    SciTech Connect

    Kalavagunta, C; Lasio, G; Yi, B; Zhou, J; Lin, M

    2015-06-15

    Purpose: It is important to estimate dose to pacemaker (PM)/Implantable Cardioverter Defibrillator (ICD) before undertaking Accelerated Partial Breast Treatment using High Dose Rate (HDR) brachytherapy. Kim et al. have reported HDR PM/ICD dose using a single-source balloon applicator. To the authors knowledge, there have so far not been any published PM/ICD dosimetry literature for the Strut Adjusted Volume Implant (SAVI, Cianna Medical, Aliso Viejo, CA). This study aims to fill this gap by generating a dose look up table (LUT) to predict maximum dose to the PM/ICD in SAVI HDR brachytherapy. Methods: CT scans for 3D dosimetric planning were acquired for four SAVI applicators (6−1-mini, 6−1, 8−1 and 10−1) expanded to their maximum diameter in air. The CT datasets were imported into the Elekta Oncentra TPS for planning and each applicator was digitized in a multiplanar reconstruction window. A dose of 340 cGy was prescribed to the surface of a 1 cm expansion of the SAVI applicator cavity. Cartesian coordinates of the digitized applicator were determined in the treatment leading to the generation of a dose distribution and corresponding distance-dose prediction look up table (LUT) for distances from 2 to 15 cm (6-mini) and 2 to 20 cm (10–1).The deviation between the LUT doses and the dose to the cardiac device in a clinical case was evaluated. Results: Distance-dose look up table were compared to clinical SAVI plan and the discrepancy between the max dose predicted by the LUT and the clinical plan was found to be in the range (−0.44%, 0.74%) of the prescription dose. Conclusion: The distance-dose look up tables for SAVI applicators can be used to estimate the maximum dose to the ICD/PM, with a potential usefulness for quick assessment of dose to the cardiac device prior to applicator placement.

  9. Predictors of Permanent Pacemaker Implantation After Coronary Artery Bypass Grafting and Valve Surgery in Adult Patients in Current Surgical Era

    PubMed Central

    Al-Ghamdi, Bandar; Mallawi, Yaseen; Shafquat, Azam; Ledesma, Alexandra; AlRuwaili, Nadiah; Shoukri, Mohamed; Khan, Shahid; Al Sanei, Aly

    2016-01-01

    Background Permanent pacemaker (PPM) implantation after cardiac surgery is required in 0.4-6% of patients depending on cardiac surgery type. PPM implantation in the early postoperative period may reduce morbidity and postoperative hospital stay. We performed a retrospective review of electronic medical records of adult patients with coronary artery bypass grafting (CABG), valve surgery, or both, over a 3-year period. Our aim was to identify predictors of PPM requirements and PPM dependency on follow-up in the current surgical era. Methods After exclusion of patients with congenital heart disease, patients who already had a PPM or implantable cardioverter defibrillator (ICD), and patients with an indication for PPM or ICD before surgery, we identified 1,234 adult patients who underwent cardiac surgery between January 2007 and December 2009. A retrospective review of electronic medical records and pacemaker clinic data was performed. Results Patients’ mean age was 46.65 ± 16 years, and 59% were males. CABG was performed in 575 (46.6%) cases, aortic valve replacement in 263 (21.3%), mitral valve replacement in 333 (27%), and tricuspid valve replacement in 76 patients (6.2%). Twenty patients (1.6%) required implantation of a PPM postoperatively. Indications for PPM implantation included complete atrioventricular (AV) block in 13 (65%), sick sinus syndrome in three (15%), and atrial fibrillation (AF) with a slow ventricular rate in four (20%). Predictors for PPM requirement by multivariate analysis were the presence of pulmonary hypertension (P-HTN), reoperation, and left bundle branch block (LBBB) (P < 0.05). Late follow-up was available in 18 patients, at 84.5 ± 30 months. Eleven patients (61%) were PPM dependent on long-term follow-up. Conclusions Patients at high risk for PPM implantation after cardiac surgery include those with P-HTN, reoperation, and pre-existing LBBB. Of those receiving a PPM, about one-third will recover at least partially at long

  10. Impaired regulation of cardiac function in sepsis, SIRS, and MODS.

    PubMed

    Werdan, Karl; Schmidt, Hendrik; Ebelt, Henning; Zorn-Pauly, Klaus; Koidl, Bernd; Hoke, Robert Sebastian; Heinroth, Konstantin; Müller-Werdan, Ursula

    2009-04-01

    In sepsis, systemic inflammatory response syndrome (SIRS), and multiorgan dysfunction syndrome (MODS), a severe prognostically relevant cardiac autonomic dysfunction exists, as manifested by a strong attenuation of sympathetically and vagally mediated heart rate variability (HRV). The mechanisms underlying this attenuation are not limited to the nervous system. They also include alterations of the cardiac pacemaker cells on a cellular level. As shown in human atrial cardiomyocytes, endotoxin interacts with cardiac hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channels, which mediate the pacemaker current If and play an important role in transmitting sympathetic and vagal signals on heart rate and HRV. Moreover, endotoxin sensitizes cardiac HCN channels to sympathetic signals. These findings identify endotoxin as a pertinent modulator of the autonomic nervous regulation of heart function. In MODS, the vagal pathway of the autonomic nervous system is particularly compromised, leading to an attenuation of the cholinergic antiinflammatory reflex. An amelioration of the blunted vagal activity appears to be a promising novel therapeutic target to achieve a suppression of the inflammatory state and thereby an improvement of prognosis in MODS patients. Preliminary data revealed therapeutic benefits (increased survival rates and improvements of the depressed vagal activity) of the administration of statins, beta-blockers, and angiotensin-converting enzyme inhibitors in patients with MODS.

  11. From syncitium to regulated pump: a cardiac muscle cellular update

    PubMed Central

    2011-01-01

    The primary purpose of this article is to present a basic overview of some key teaching concepts that should be considered for inclusion in an six- to eight-lecture introductory block on the regulation of cardiac performance for graduate students. Within the context of cardiac excitation-contraction coupling, this review incorporates information on Ca2+ microdomains and local control theory, with particular emphasis on the role of Ca2+ sparks as a key regulatory component of ventricular myocyte contraction dynamics. Recent information pertaining to local Ca2+ cycling in sinoatrial nodal cells (SANCs) as a mechanism underlying cardiac automaticity is also presented as part of the recently described coupled-clock pacemaker system. The details of this regulation are emerging; however, the notion that the sequestration and release of Ca2+ from internal stores in SANCs (similar to that observed in ventricular myocytes) regulates the rhythmic excitation of the heart (i.e., membrane ion channels) is an important advancement in this area. The regulatory role of cardiac adrenergic receptors on cardiac rate and function is also included, and fundamental concepts related to intracellular signaling are discussed. An important point of emphasis is that whole organ cardiac dynamics can be traced back to cellular events regulating intracellular Ca2+ homeostasis and, as such, provides an important conceptual framework from which students can begin to think about whole organ physiology in health and disease. Greater synchrony of Ca2+-regulatory mechanisms between ventricular and pacemaker cells should enhance student comprehension of complex regulatory phenomenon in cardiac muscle. PMID:21385997

  12. A Novel Way Of Repair Of Insulation Breaks During Pacemaker Generator Replacement

    PubMed Central

    Manzoor Ali, Syed; Iqbal, Khurshid; Tramboo, Nisar A; Lone, Aijaz A; Kaul, Suresh; Kaul, Neelam; Hafiz, Imran

    2009-01-01

    Minor abrasions can occur while mobilising old lead during pacemaker generator replacement necesittating placement of additional lead adding to the financial burden and junk in heart. We describe a novel way of repair of old pacemaker lead preventing additional lead placement. PMID:19763196

  13. 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

    2015-06-03

    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.

  14. Are Cav1.3 pacemaker channels in chromaffin cells?

    PubMed Central

    Striessnig, Joerg

    2011-01-01

    Mouse and rat chromaffin cells (MCCs, RCCs) fire spontaneously at rest and their activity is mainly supported by the two L-type Ca2+ channels expressed in these cells (Cav1.2 and Cav1.3). Using Cav1.3−/− KO MCCs we have shown that Cav1.3 possess all the prerequisites for carrying subthreshold currents that sustain low frequency cell firing near resting (0.5 to 2 Hz at −50 mV):1 low-threshold and steep voltage dependence of activation, slow and incomplete inactivation during pulses of several hundreds of milliseconds. Cav1.2 contributes also to pacemaking MCCs and possibly even Na+ channels may participate in the firing of a small percentage of cells. We now show that at potentials near resting (−50 mV), Cav1.3 carries equal amounts of Ca2+ current to Cav1.2 but activates at 9 mV more negative potentials. MCCs express only TTX-sensitive Nav1 channels that activate at 24 mV more positive potentials than Cav1.3 and are fully inactivating. Their blockade prevents the firing only in a small percentage of cells (13%). This suggests that the order of importance with regard to pacemaking MCCs is: Cav1.3, Cav1.2 and Nav1. The above conclusions, however, rely on the proper use of DHPs, whose blocking potency is strongly holding potential dependent. We also show that small increases of KCl concentration steadily depolarize the MCCs causing abnormally increased firing frequencies, lowered and broadened AP waveforms and an increased facility of switching “non-firing” into “firing” cells that may lead to erroneous conclusions about the role of Cav1.3 and Cav1.2 as pacemaker channels in MCCs.2 PMID:21406973

  15. 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.

  16. Teaching cardiac electrophysiology modeling to undergraduate students: laboratory exercises and GPU programming for the study of arrhythmias and spiral wave dynamics.

    PubMed

    Bartocci, Ezio; Singh, Rupinder; von Stein, Frederick B; Amedome, Avessie; Caceres, Alan Joseph J; Castillo, Juan; Closser, Evan; Deards, Gabriel; Goltsev, Andriy; Ines, Roumwelle Sta; Isbilir, Cem; Marc, Joan K; Moore, Diquan; Pardi, Dana; Sadhu, Sandeep; Sanchez, Samuel; Sharma, Pooja; Singh, Anoopa; Rogers, Joshua; Wolinetz, Aron; Grosso-Applewhite, Terri; Zhao, Kai; Filipski, Andrew B; Gilmour, Robert F; Grosu, Radu; Glimm, James; Smolka, Scott A; Cherry, Elizabeth M; Clarke, Edmund M; Griffeth, Nancy; Fenton, Flavio H

    2011-12-01

    As part of a 3-wk intersession workshop funded by a National Science Foundation Expeditions in Computing award, 15 undergraduate students from the City University of New York(1) collaborated on a study aimed at characterizing the voltage dynamics and arrhythmogenic behavior of cardiac cells for a broad range of physiologically relevant conditions using an in silico model. The primary goal of the workshop was to cultivate student interest in computational modeling and analysis of complex systems by introducing them through lectures and laboratory activities to current research in cardiac modeling and by engaging them in a hands-on research experience. The success of the workshop lay in the exposure of the students to active researchers and experts in their fields, the use of hands-on activities to communicate important concepts, active engagement of the students in research, and explanations of the significance of results as the students generated them. The workshop content addressed how spiral waves of electrical activity are initiated in the heart and how different parameter values affect the dynamics of these reentrant waves. Spiral waves are clinically associated with tachycardia, when the waves remain stable, and with fibrillation, when the waves exhibit breakup. All in silico experiments were conducted by simulating a mathematical model of cardiac cells on graphics processing units instead of the standard central processing units of desktop computers. This approach decreased the run time for each simulation to almost real time, thereby allowing the students to quickly analyze and characterize the simulated arrhythmias. Results from these simulations, as well as some of the background and methodology taught during the workshop, is presented in this article along with the programming code and the explanations of simulation results in an effort to allow other teachers and students to perform their own demonstrations, simulations, and studies.

  17. Cardiac rehabilitation after myocardial infarction.

    PubMed

    Contractor, Aashish S

    2011-12-01

    Cardiac rehabilitation/secondary prevention programs are recognized as integral to the comprehensive care of patients with coronary heart disease (CHD), and as such are recommended as useful and effective (Class I) by the American Heart Association and the American College of Cardiology in the treatment of patients with CHD. The term cardiac rehabilitation refers to coordinated, multifaceted interventions designed to optimize a cardiac patient's physical, psychological, and social functioning, in addition to stabilizing, slowing, or even reversing the progression of the underlying atherosclerotic processes, thereby reducing morbidity and mortality. Cardiac rehabilitation, aims at returning the patient back to normal functioning in a safe and effective manner and to enhance the psychosocial and vocational state of the patient. The program involves education, exercise, risk factor modification and counselling. A meta-analysis based on a review of 48 randomized trials that compared outcomes of exercise-based rehabilitation with usual medical care, showed a reduction of 20% in total mortality and 26% in cardiac mortality rates, with exercise-based rehabilitation compared with usual medical care. Risk stratification helps identify patients who are at increased risk for exercise-related cardiovascular events and who may require more intensive cardiac monitoring in addition to the medical supervision provided for all cardiac rehabilitation program participants. During exercise, the patients' ECG is continuously monitored through telemetry, which serves to optimize the exercise prescription and enhance safety. The safety of cardiac rehabilitation exercise programs is well established, and the occurrence of major cardiovascular events during supervised exercise is extremely low. As hospital stays decrease, cardiac rehabilitation is assuming an increasingly important role in secondary prevention. In contrast with its growing importance internationally, there are very few

  18. Radiation dose monitoring in a breast cancer patient with a pacemaker: a case report.

    PubMed

    Nibhanupudy, J R; de Jesus, M A; Fujita, M; Goldson, A L

    2001-01-01

    A pacemaker-bearing patient with left-sided breast cancer was treated with adjuvant external beam radiation therapy to the intact breast. She was treated via tangential fields and a single anterior supraclavicular field using 6-MV x-rays. The pacemaker, originally in the treatment field, was removed and a new one placed 4 cm outside the radiation field prior to treatment. Silicon diode chamber Keithley-Farmer type 0.6 cc ionization chamber, and lithium fluoride (LiF) (TLD) chips were used to measure, in vivo, the dose to the pacemaker. From all the fields treated, total dose to the pacemaker was 164 cGy by diode measurements, 182 cGy by ionization chamber measurements, and 171 cGy by TLD measurements. The pacemaker functioned normally throughout the course of treatment.

  19. The Epigenetic Regulator HDAC1 Modulates Transcription of a Core Cardiogenic Program in Human Cardiac Mesenchymal Stromal Cells Through a p53-Dependent Mechanism.

    PubMed

    Moore, Joseph B; Zhao, John; Keith, Matthew C L; Amraotkar, Alok R; Wysoczynski, Marcin; Hong, Kyung U; Bolli, Roberto

    2016-12-01

    Histone deacetylase (HDAC) regulation is an essential process in myogenic differentiation. Inhibitors targeting the activity of specific HDAC family members have been shown to enhance the cardiogenic differentiation capacity of discrete progenitor cell types; a key property of donor cell populations contributing to their afforded benefits in cardiac cell therapy applications. The influence of HDAC inhibition on cardiac-derived mesenchymal stromal cell (CMC) transdifferentiation or the role of specific HDAC family members in dictating cardiovascular cell lineage specification has not been investigated. In the current study, the consequences of HDAC inhibition on patient-derived CMC proliferation, cardiogenic program activation, and cardiovascular differentiation/cell lineage specification were investigated using pharmacologic and genetic targeting approaches. Here, CMCs exposed to the pan-HDAC inhibitor sodium butyrate exhibited induction of a cardiogenic transcriptional program and heightened expression of myocyte and endothelial lineage-specific markers when coaxed to differentiate in vitro. Further, shRNA knockdown screens revealed CMCs depleted of HDAC1 to promote the induction of a cardiogenic transcriptional program characterized by enhanced expression of cardiomyogenic- and vasculogenic-specific markers, a finding which depended on and correlated with enhanced acetylation and stabilization of p53. Cardiogenic gene activation and elevated p53 expression levels observed in HDAC1-depleted CMCs were associated with improved aptitude to assume a cardiomyogenic/vasculogenic cell-like fate in vitro. These results suggest that HDAC1 depletion-induced p53 expression alters CMC cell fate decisions and identify HDAC1 as a potential exploitable target to facilitate CMC-mediated myocardial repair in ischemic cardiomyopathy. Stem Cells 2016;34:2916-2929.

  20. The Autonomic Nervous System Regulates the Heart Rate through cAMP-PKA Dependent and Independent Coupled-Clock Pacemaker Cell Mechanisms.

    PubMed

    Behar, Joachim; Ganesan, Ambhighainath; Zhang, Jin; Yaniv, Yael

    2016-01-01

    Sinoatrial nodal cells (SANCs) generate spontaneous action potentials (APs) that control the cardiac rate. The brain modulates SANC automaticity, via the autonomic nervous system, by stimulating membrane receptors that activate (adrenergic) or inactivate (cholinergic) adenylyl cyclase (AC). However, these opposing afferents are not simply additive. We showed that activation of adrenergic signaling increases AC-cAMP/PKA signaling, which mediates the increase in the SANC AP firing rate (i.e., positive chronotropic modulation). However, there is a limited understanding of the underlying internal pacemaker mechanisms involved in the crosstalk between cholinergic receptors and the decrease in the SANC AP firing rate (i.e., negative chronotropic modulation). We hypothesize that changes in AC-cAMP/PKA activity are crucial for mediating either decrease or increase in the AP firing rate and that the change in rate is due to both internal and membrane mechanisms. In cultured adult rabbit pacemaker cells infected with an adenovirus expressing the FRET sensor AKAR3, PKA activity and AP firing rate were tightly linked in response to either adrenergic receptor stimulation (by isoproterenol, ISO) or cholinergic stimulation (by carbachol, CCh). To identify the main molecular targets that mediate between PKA signaling and pacemaker function, we developed a mechanistic computational model. The model includes a description of autonomic-nervous receptors, post- translation signaling cascades, membrane molecules, and internal pacemaker mechanisms. Yielding results similar to those of the experiments, the model simulations faithfully reproduce the changes in AP firing rate in response to CCh or ISO or a combination of both (i.e., accentuated antagonism). Eliminating AC-cAMP-PKA signaling abolished the core effect of autonomic receptor stimulation on the AP firing rate. Specifically, disabling the phospholamban modulation of the SERCA activity resulted in a significantly reduced effect

  1. The Autonomic Nervous System Regulates the Heart Rate through cAMP-PKA Dependent and Independent Coupled-Clock Pacemaker Cell Mechanisms

    PubMed Central

    Behar, Joachim; Ganesan, Ambhighainath; Zhang, Jin; Yaniv, Yael

    2016-01-01

    Sinoatrial nodal cells (SANCs) generate spontaneous action potentials (APs) that control the cardiac rate. The brain modulates SANC automaticity, via the autonomic nervous system, by stimulating membrane receptors that activate (adrenergic) or inactivate (cholinergic) adenylyl cyclase (AC). However, these opposing afferents are not simply additive. We showed that activation of adrenergic signaling increases AC-cAMP/PKA signaling, which mediates the increase in the SANC AP firing rate (i.e., positive chronotropic modulation). However, there is a limited understanding of the underlying internal pacemaker mechanisms involved in the crosstalk between cholinergic receptors and the decrease in the SANC AP firing rate (i.e., negative chronotropic modulation). We hypothesize that changes in AC-cAMP/PKA activity are crucial for mediating either decrease or increase in the AP firing rate and that the change in rate is due to both internal and membrane mechanisms. In cultured adult rabbit pacemaker cells infected with an adenovirus expressing the FRET sensor AKAR3, PKA activity and AP firing rate were tightly linked in response to either adrenergic receptor stimulation (by isoproterenol, ISO) or cholinergic stimulation (by carbachol, CCh). To identify the main molecular targets that mediate between PKA signaling and pacemaker function, we developed a mechanistic computational model. The model includes a description of autonomic-nervous receptors, post- translation signaling cascades, membrane molecules, and internal pacemaker mechanisms. Yielding results similar to those of the experiments, the model simulations faithfully reproduce the changes in AP firing rate in response to CCh or ISO or a combination of both (i.e., accentuated antagonism). Eliminating AC-cAMP-PKA signaling abolished the core effect of autonomic receptor stimulation on the AP firing rate. Specifically, disabling the phospholamban modulation of the SERCA activity resulted in a significantly reduced effect

  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. Cardiac Cephalgia

    PubMed Central

    Wassef, Nancy; Ali, Ali Turab; Katsanevaki, Alexia-Zacharoula; Nishtar, Salman

    2014-01-01

    Although most of the patients presenting with ischemic heart disease have chest pains, there are other rare presenting symptoms like cardiac cephalgia. In this report, we present a case of acute coronary syndrome with an only presentation of exertional headache. It was postulated as acute presentation of coronary artery disease, due to previous history of similar presentation associated with some chest pains with previous left coronary artery stenting. We present an unusual case with cardiac cephalgia in a young patient under the age of 50 which was not reported at that age before. There are four suggested mechanisms for this cardiac presentation. PMID:28352454

  4. Mitochondrial biogenesis in cardiac pathophysiology.

    PubMed

    Rimbaud, Stéphanie; Garnier, Anne; Ventura-Clapier, Renée

    2009-01-01

    Cardiac performance depends on a fine balance between the work the heart has to perform to satisfy the needs of the body and the energy that it is able to produce. Thus, energy production by oxidative metabolism, the main energy source of the cardiac muscle, has to be strictly regulated to adapt to cardiac work. Mitochondrial biogenesis is the mechanism responsible for mitochondrial component synthesis and assembly. This process controls mitochondrial content and thus correlates with energy production that, in turn, sustains cardiac contractility. Mitochondrial biogenesis should be finely controlled to match cardiac growth and cardiac work. When the heart is subjected to an increase in work in response to physiological and pathological challenges, it adapts by increasing its mass and expressing a new genetic program. In response to physiological stimuli such as endurance training, mitochondrial biogenesis seems to follow a program involving increased cardiac mass. But in the context of pathological hypertrophy, the modifications of this mechanism remain unclear. What appears clear is that mitochondrial biogenesis is altered in heart failure, and the imbalance between cardiac work demand and energy production represents a major factor in the development of heart failure.

  5. Pyloric obstruction secondary to epicardial pacemaker implantation: a case report.

    PubMed

    Bedoya Nader, G; Kellihan, H B; Bjorling, D E; McAnulty, J

    2017-02-01

    A 10-year old Lhasa Apso dog was presented for an acute history of exercise intolerance and hind limb weakness. High grade second degree atrioventricular block with an atrial rate of 200 beats per minute, ventricular rate of 40 beats per minute and an intermittent ventricular escape rhythm, was diagnosed on electrocardiograph. A transdiaphragmatic, unipolar, epicardial pacemaker was implanted without immediate surgical complications. Severe vomiting was noted 12 h post-operatively. Abdominal ultrasound and a barium study supported a diagnosis of pyloric outflow obstruction and exploratory abdominal surgery was performed. The pyloric outflow tract appeared normal and no other causes of an outflow obstruction were identified. The epicardial generator was repositioned from the right to the left abdominal wall. Pyloric cell pacing was presumed to be the cause for the pyloric obstruction and severe vomiting, and this was thought to be due to close proximity of the pacemaker generator to the pylorus situated in the right abdominal wall. Repositioning of the pulse generator to the left abdominal wall resulted in resolution of vomiting.

  6. 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.

  7. Pacemaker dynamics in the full Morris-Lecar model

    NASA Astrophysics Data System (ADS)

    González-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.

  8. 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.

  9. 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.

  10. Nuclear cardiac

    SciTech Connect

    Slutsky, R.; Ashburn, W.L.

    1982-01-01

    The relationship between nuclear medicine and cardiology has continued to produce a surfeit of interesting, illuminating, and important reports involving the analysis of cardiac function, perfusion, and metabolism. To simplify the presentation, this review is broken down into three major subheadings: analysis of myocardial perfusion; imaging of the recent myocardial infarction; and the evaluation of myocardial function. There appears to be an increasingly important relationship between cardiology, particularly cardiac physiology, and nuclear imaging techniques. (KRM)

  11. 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 β-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 ± 0.5°C 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 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 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.

  12. [Cardiac autonomic blockade in sinus disease and indication for a pacemaker].

    PubMed

    Solórzano Martín, C J; Delgado Caro, G; Lugo Peña, P

    1990-01-01

    Functional autonomic blockade (FAB) with metoprolol (0.2 mg/kg body weight) and atropine sulphate (0.04 mg/kg) was carried out in 23 patients, 20 to 81 years old (mean age 61 years) with symptomatic sick sinus syndrome with clinical indication for permanent pacing. Several measurements were determined before and after FAB, 7 had normal intrinsic heart rate (IHR) and 16 abnormal. With normal IHR, 3 had severe autonomic regulation disturbances and in only two patients the corrected sinus nodal recovery time (SNRTC) and the sinoatrial conduction time (SACT) were prolonged after FAB. On the 16 patients with abnormal IHR only 4 had severe extrinsic autonomic influence and 15 had SACT and SNRTC prolonged after FAB. All measurements were determined by standard electrocardiographic surface tracings. Indications for permanent pacing were reduced to intrinsic sick sinus syndrome and bradycardia with severe autonomic disturbances in symptomatic patients.

  13. Cardiac cameras.

    PubMed

    Travin, Mark I

    2011-05-01

    Cardiac imaging with radiotracers plays an important role in patient evaluation, and the development of suitable imaging instruments has been crucial. While initially performed with the rectilinear scanner that slowly transmitted, in a row-by-row fashion, cardiac count distributions onto various printing media, the Anger scintillation camera allowed electronic determination of tracer energies and of the distribution of radioactive counts in 2D space. Increased sophistication of cardiac cameras and development of powerful computers to analyze, display, and quantify data has been essential to making radionuclide cardiac imaging a key component of the cardiac work-up. Newer processing algorithms and solid state cameras, fundamentally different from the Anger camera, show promise to provide higher counting efficiency and resolution, leading to better image quality, more patient comfort and potentially lower radiation exposure. While the focus has been on myocardial perfusion imaging with single-photon emission computed tomography, increased use of positron emission tomography is broadening the field to include molecular imaging of the myocardium and of the coronary vasculature. Further advances may require integrating cardiac nuclear cameras with other imaging devices, ie, hybrid imaging cameras. The goal is to image the heart and its physiological processes as accurately as possible, to prevent and cure disease processes.

  14. Cause and Long-Term Outcome of Cardiac Tamponade.

    PubMed

    Sánchez-Enrique, Cristina; Nuñez-Gil, Iván J; Viana-Tejedor, Ana; De Agustín, Alberto; Vivas, David; Palacios-Rubio, Julián; Vilchez, Jean Paul; Cecconi, Alberto; Macaya, Carlos; Fernández-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 ± 17 years (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 10.4 years, 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.

  15. 76 FR 64223 - Cardiovascular Devices; Reclassification of External Pacemaker Pulse Generator Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-17

    ... interference, or improper programming can cause sustained high rate pacing, which can lead to arrhythmias such... arrhythmias; and 4. Micro/macro shocks--Uncontrolled leakage currents or patient auxiliary currents can cause an electric shock resulting in an arrhythmia or cardiac tissue damage. VI. Summary of Reasons...

  16. Glocal Clinical Registries: Pacemaker Registry Design and Implementation for Global and Local Integration – Methodology and Case Study

    PubMed Central

    da Silva, Kátia Regina; Costa, Roberto; Crevelari, Elizabeth Sartori; Lacerda, Marianna Sobral; de Moraes Albertini, Caio Marcos; Filho, Martino Martinelli; Santana, José Eduardo; Vissoci, João 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

  17. Anaesthesia Application for Cardiac Denervation in a Patient with Long QT Syndrome and Cardiomyopathy

    PubMed Central

    Karadeniz, Ümit; Demir, Aslı; Koçulu, Rabia

    2016-01-01

    Long QT syndrome is a congenital disorder that is characterized by a prolongation of the QT interval on electrocardiograms and a propensity to ventricular tachyarrhythmias, which may lead to syncope, cardiac arrest or sudden death. Cardiomyopathy and pulmonary hypertension diseases have additional risks in anaesthesia management. In this study, we emphasize on one lung ventilation, pacemaker-implantable cardioverter–defibrillator and the anaesthesia management process in a patient with long QT syndrome, cardiomyopathy and pulmonary hypertension who underwent thoracic sympathectomy. PMID:27366557

  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 α-sarcomeric actin and vimentin, and negative for α-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.

  19. Implementation study of an analog spiking neural network for assisting cardiac delay prediction in a cardiac resynchronization therapy device.

    PubMed

    Sun, Qing; Schwartz, François; Michel, Jacques; Herve, Yannick; Dalmolin, Renzo

    2011-06-01

    In this paper, we aim at developing an analog spiking neural network (SNN) for reinforcing the performance of conventional cardiac resynchronization therapy (CRT) devices (also called biventricular pacemakers). Targeting an alternative analog solution in 0.13- μm CMOS technology, this paper proposes an approach to improve cardiac delay predictions in every cardiac period in order to assist the CRT device to provide real-time optimal heartbeats. The primary analog SNN architecture is proposed and its implementation is studied to fulfill the requirement of very low energy consumption. By using the Hebbian learning and reinforcement learning algorithms, the intended adaptive CRT device works with different functional modes. The simulations of both learning algorithms have been carried out, and they were shown to demonstrate the global functionalities. To improve the realism of the system, we introduce various heart behavior models (with constant/variable heart rates) that allow pathologic simulations with/without noise on the signals of the input sensors. The simulations of the global system (pacemaker models coupled with heart models) have been investigated and used to validate the analog spiking neural network implementation.

  20. [Functional organization of myogenic pacemaker of the stomach in conditions of hunger and satiation].

    PubMed

    Kromin, A A; Kuznetsov, A M

    2002-06-01

    In chronic experiments, we have studied electrical activity of muscles of the gastro-esophageal sphincter, small curvature, corpus and antrum of the stomach in conditions of hunger, food intake behaviour and satiation of the rabbits. The aim of this study involved particularities of the electrical activity of myogenic pacemaker zone of the stomach. It has been shown that function of myogenic pacemaker of the rabbit stomach is performed by smooth muscles of the small curvature of the stomach. Pacemaker properties of muscles of the small curvature of the stomach are performed in conditions of food intake behaviour and satiation.

  1. Myocardial abscess and bacteremia complicating Mycobacterium fortuitum pacemaker infection: case report and review of the literature.

    PubMed

    Al Soub, Hussam; Al Maslamani, Mona; Al Khuwaiter, Jameela; El Deeb, Yasser; Abu Khattab, Mohammed

    2009-11-01

    A case of pacemaker infection complicated by bacteremia and myocardial abscess caused by Mycobacterium fortuitum is reported and 9 other cases of pacemaker infection associated with rapidly growing mycobacteria are reviewed. Most cases developed within 6 months from implantation suggesting nosocomial acquisition. Wound discharge, fever, and pain at generator site were the most common presenting features. At presentation they had a median duration of symptoms of 34 days. Concomitant bacteremia was present in half of the cases. Antibiotics therapy and removal of the pacemaker system were needed to achieve cure in the majority of cases. Clarithromycin and fluoroquinolones were the most commonly used antibiotics.

  2. Transvenous extraction of an abandoned endocardial pacemaker lead in a dog.

    PubMed

    LeBlanc, Nicole; Scollan, Katherine; Sisson, David

    2014-03-01

    A 6-year-old male castrated labrador retriever presented with endocardial pacemaker infection following migration and subsequent repositioning of the pulse generator. An epicardial lead and pulse generator were surgically implanted and the endocardial lead could not be removed with manual traction. The endocardial lead was severed, anchored, and abandoned at the thoracic inlet. The patient presented 4 months later with endocardial lead migration, bacteremia, and suspected glomerulonephritis. The endocardial pacemaker lead was transvenously extracted using a mechanical dilator sheath and locking stylet. This report of transvenous pacemaker lead extraction in a dog addresses the challenges and describes recent advances in extraction devices.

  3. [Possibilities of minimal invasive cardiac catheter interventions in the dog].

    PubMed

    Glaus, T M; Unterer, S; Tomsa, K; Baumgartner, C; Geissbühler, U; Gardelle, O; Reusch, C

    2003-09-01

    The therapeutic possibilities in veterinary cardiology have developed rapidly in the past few years. Whereas until recently cardiac intervention in dogs could only be performed by thoracotomy, new minimally invasive techniques are adopted. Procedures like balloondilatation of pulmonic stenosis, coil embolisation of patent ductus arteriosus, pacemaker implantation in symptomatic bradyarrhyhtmia, and palliative balloon pericardiotomy are becoming more and more established. These alternative interventional methods are attractive, because no postsurgical pain and no complications potentially associated with thoracotomy ensue. The knowledge of such new treatment modalities and particularly the indications for an intervention are prerequisites to apply them optimally and broadly.

  4. Late-presenting complete heart block after pediatric cardiac surgery

    PubMed Central

    Nasser, Bana Agha; Mesned, Abdu Rahman; Mohamad, Tagelden; Kabbani, Mohamad S.

    2015-01-01

    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

  5. Left Ventricular Synchrony and Function in Pediatric Patients with Definitive Pacemakers

    PubMed Central

    Ortega, Michel Cabrera; Morejón, Adel Eladio Gonzales; Ricardo, Giselle Serrano

    2013-01-01

    Background Chronic right ventricular pacing (RVP) induces a dyssynchronous contraction pattern, producing interventricular and intraventricular asynchrony. Many studies have shown the relationship of RVP with impaired left ventricular (LV) form and function. Objective The aim of this study was to evaluate LV synchrony and function in pediatric patients receiving RVP in comparison with those receiving LV pacing (LVP). Methods LV systolic and diastolic function and synchrony were evaluated in 80 pediatric patients with either nonsurgical or postsurgical complete atrioventricular block, with pacing from either the RV endocardium (n = 40) or the LV epicardium (n = 40). Echocardiographic data obtained before pacemaker implantation, immediately after it, and at the end of a mean follow-up of 6.8 years were analyzed. Results LV diastolic function did not change in any patient during follow-up. LV systolic function was preserved in patients with LVP. However, in children with RVP the shortening fraction and ejection fraction decreased from medians of 41% ± 2.6% and 70% ± 6.9% before implantation to 32% ± 4.2% and 64% ± 2.5% (p < 0.0001 and p < 0.0001), respectively, at final follow-up. Interventricular mechanical delay was significantly larger with RVP (66 ± 13 ms) than with LVP (20 ± 8 ms). Similarly, the following parameters were significantly different in the two groups: LV mechanical delay (RVP: 69 ± 6 ms, LVP: 30 ± 11 ms, p < 0.0001); septal to lateral wall motion delay (RVP: 75 ± 19 ms, LVP: 42 ± 10 ms, p < 0.0001); and, septal to posterior wall motion delay (RVP: 127 ± 33 ms, LVP: 58 ± 17 ms, p < 0.0001). Conclusion Compared with RV endocardium, LV epicardium is an optimal site for pacing to preserve cardiac synchrony and function. PMID:24061683

  6. Endoscopic Electrosurgery in Patients with Cardiac Implantable Electronic Devices

    PubMed Central

    Baeg, Myong Ki; Kim, Sang-Woo; Ko, Sun-Hye; Lee, Yoon Bum; Hwang, Seawon; Lee, Bong-Woo; Choi, Hye Jin; Park, Jae Myung; Lee, In-Seok; Oh, Yong-Seog; Choi, Myung-Gyu

    2016-01-01

    Background/Aims: Patients with cardiac implantable electronic devices (CIEDs) undergoing endoscopic electrosurgery (EE) are at a risk of electromagnetic interference (EMI). We aimed to analyze the effects of EE in CIED patients. Methods: Patients with CIED who underwent EE procedures such as snare polypectomy, endoscopic submucosal dissection (ESD), and endoscopic retrograde cholangiopancreatography (ERCP) with endoscopic sphincterotomy (EST) were retrospectively analyzed. Postprocedural symptoms as well as demographic and outpatient follow-up data were reviewed through medical records. Electrical data, including preprocedural and postprocedural arrhythmia records, were reviewed through pacemaker interrogation, 24-hour Holter monitoring, or electrocardiogram. Results: Fifty-nine procedures in 49 patients were analyzed. Fifty procedures were performed in 43 patients with a pacemaker, and nine were performed in six patients with an implantable cardioverter-defibrillator. There were one gastric and 44 colon snare polypectomies, five gastric and one colon ESDs, and eight ERCPs with EST. Fifty-five cases of electrical follow-up were noted, with two postprocedural changes not caused by EE. Thirty-one pacemaker interrogations had procedure recordings, with two cases of asymptomatic tachycardia. All patients were asymptomatic with no adverse events. Conclusions: Our study reports no adverse events from EE in patients with CIED, suggesting that this procedure is safe. However, because of the possibility of EMI, recommendations on EE should be followed. PMID:26867552

  7. Nonlinear oscillations in a muscle pacemaker cell model

    NASA Astrophysics Data System (ADS)

    González-Miranda, J. M.

    2017-02-01

    This article presents a numerical simulation study of the nonlinear oscillations displayed by the Morris-Lecar model [Biophys. J. 35 (1981) 193] for the oscillations experimentally observed in the transmembrane potential of a muscle fiber subject to an external electrical stimulus. We consider the model in the case when there is no external stimulation, aiming to establish the ability of the model to display biophysically reasonable pacemaker dynamics. We obtain 2D bifurcation diagrams showing that indeed the model presents oscillatory dynamics, displaying the two main types of action potentials that are observed in muscle fibers. The results obtained are shown to be structurally stable; that is, robust against changes in the values of system parameters. Moreover, it is demonstrated how the model is appropriate to analyze the action potentials observed in terms of the transmembrane currents creating them.

  8. Pacemakers in large arrays of oscillators with nonlocal coupling

    NASA Astrophysics Data System (ADS)

    Jaramillo, Gabriela; Scheel, Arnd

    2016-02-01

    We model pacemaker effects of an algebraically localized heterogeneity in a 1 dimensional array of oscillators with nonlocal coupling. We assume the oscillators obey simple phase dynamics and that the array is large enough so that it can be approximated by a continuous nonlocal evolution equation. We concentrate on the case of heterogeneities with positive average and show that steady solutions to the nonlocal problem exist. In particular, we show that these heterogeneities act as a wave source. This effect is not possible in 3 dimensional systems, such as the complex Ginzburg-Landau equation, where the wavenumber of weak sources decays at infinity. To obtain our results we use a series of isomorphisms to relate the nonlocal problem to the viscous eikonal equation. We then use Fredholm properties of the Laplace operator in Kondratiev spaces to obtain solutions to the eikonal equation, and by extension to the nonlocal problem.

  9. Fetal growth restriction and the programming of heart growth and cardiac insulin-like growth factor 2 expression in the lamb

    PubMed Central

    Wang, Kimberley C W; Zhang, Lei; McMillen, I Caroline; Botting, Kimberley J; Duffield, Jaime A; Zhang, Song; Suter, Catherine M; Brooks, Doug A; Morrison, Janna L

    2011-01-01

    Abstract Reduced growth in fetal life together with accelerated growth in childhood, results in a ∼50% greater risk of coronary heart disease in adult life. It is unclear why changes in patterns of body and heart growth in early life can lead to an increased risk of cardiovascular disease in adulthood. We aimed to investigate the role of the insulin-like growth factors in heart growth in the growth-restricted fetus and lamb. Hearts were collected from control and placentally restricted (PR) fetuses at 137–144 days gestation and from average (ABW) and low (LBW) birth weight lambs at 21 days of age. We quantified cardiac mRNA expression of IGF-1, IGF-2 and their receptors, IGF-1R and IGF-2R, using real-time RT-PCR and protein expression of IGF-1R and IGF-2R using Western blotting. Combined bisulphite restriction analysis was used to assess DNA methylation in the differentially methylated region (DMR) of the IGF-2/H19 locus and of the IGF-2R gene. In PR fetal sheep, IGF-2, IGF-1R and IGF-2R mRNA expression was increased in the heart compared to controls. LBW lambs had a greater left ventricle weight relative to body weight as well as increased IGF-2 and IGF-2R mRNA expression in the heart, when compared to ABW lambs. No changes in the percentage of methylation of the DMRs of IGF-2/H19 or IGF-2R were found between PR and LBW when compared to their respective controls. In conclusion, a programmed increased in cardiac gene expression of IGF-2 and IGF-2R may represent an adaptive response to reduced substrate supply (e.g. glucose and/or oxygen) in order to maintain heart growth and may be the underlying cause for increased ventricular hypertrophy and the associated susceptibility of cardiomyocytes to ischaemic damage later in life. PMID:21807611

  10. SU-E-I-42: Normalized Embryo/fetus Doses for Fluoroscopically Guided Pacemaker Implantation Procedures Calculated Using a Monte Carlo Technique

    SciTech Connect

    Damilakis, J; Stratakis, J; Solomou, G

    2014-06-01

    Purpose: It is well known that pacemaker implantation is sometimes needed in pregnant patients with symptomatic bradycardia. To our knowledge, there is no reported experience regarding radiation doses to the unborn child resulting from fluoroscopy during pacemaker implantation. The purpose of the current study was to develop a method for estimating embryo/fetus dose from fluoroscopically guided pacemaker implantation procedures performed on pregnant patients during all trimesters of gestation. Methods: The Monte Carlo N-Particle (MCNP) radiation transport code was employed in this study. Three mathematical anthropomorphic phantoms representing the average pregnant patient at the first, second and third trimesters of gestation were generated using Bodybuilder software (White Rock science, White Rock, NM). The normalized embryo/fetus dose from the posteroanterior (PA), the 30° left-anterior oblique (LAO) and the 30° right-anterior oblique (RAO) projections were calculated for a wide range of kVp (50–120 kVp) and total filtration values (2.5–9.0 mm Al). Results: The results consist of radiation doses normalized to a) entrance skin dose (ESD) and b) dose area product (DAP) so that the dose to the unborn child from any fluoroscopic technique and x-ray device used can be calculated. ESD normalized doses ranged from 0.008 (PA, first trimester) to 2.519 μGy/mGy (RAO, third trimester). DAP normalized doses ranged from 0.051 (PA, first trimester) to 12.852 μGy/Gycm2 (RAO, third trimester). Conclusion: Embryo/fetus doses from fluoroscopically guided pacemaker implantation procedures performed on pregnant patients during all stages of gestation can be estimated using the method developed in this study. This study was supported by the Greek Ministry of Education and Religious Affairs, General Secretariat for Research and Technology, Operational Program ‘Education and Lifelong Learning’, ARISTIA (Research project: CONCERT)

  11. The Immunoendocrine Thymus as a Pacemaker of Lifespan.

    PubMed

    Csaba, György

    2016-06-01

    The thymus develops from an endocrine area of the foregut, and retains the ancient potencies of this region. However, later it is populated by bone marrow originated lymphatic elements and forms a combined organ, which is a central part of the immune system as well as an influential element of the endocrine orchestra. Thymus produces self-hormones (thymulin, thymosin, thymopentin, and thymus humoral factor), which are participating in the regulation of immune cell transformation and selection, and also synthesizes hormones similar to that of the other endocrine glands such as melatonin, neuropeptides, and insulin, which are transported by the immune cells to the sites of requests (packed transport). Thymic (epithelial and immune) cells also have receptors for hormones which regulate them. This combined organ, which is continuously changing from birth to senescence seems to be a pacemaker of life. This function is basically regulated by the selection of self-responsive thymocytes as their complete destruction helps the development (up to puberty) and their gradual release in case of weakened control (after puberty) causes the erosion of cells and intercellular material, named aging. This means that during aging, self-destructive and non-protective immune activities are manifested under the guidance of the involuting thymus, causing the continuous irritation of cells and organs. Possibly the pineal body is the main regulator of the pacemaker, the neonatal removal of which results in atrophy of thymus and wasting disease and its later corrosion causes the insufficiency of thymus. The co-involution of pineal and thymus could determine the aging and the time of death without external intervention; however, external factors can negatively influence both of them.

  12. Are patients with cardiac implants protected against electromagnetic interference in daily life and occupational environment?

    PubMed

    Napp, Andreas; Stunder, Dominik; Maytin, Melanie; Kraus, Thomas; Marx, Nikolaus; Driessen, Sarah

    2015-07-21

    Utilization of cardiac implants such as pacemakers and implantable cardioverter defibrillators is now commonplace among heart disease patients. The ever-increasing technological complexity of these devices is matched by the near omnipresent exposure to electric, magnetic, and electromagnetic fields (EMFs), both in everyday life and the occupational environment. Given that electromagnetic interferences (EMIs) are associated with potential risk in device patients, physicians are increasingly confronted with managing device patients with intermittent EMI and chronic occupational exposure. The current review aims to provide a contemporary overview of cardiovascular implantable electronic devices, their function and susceptibility of non-medical EMFs and provide recommendations for physicians caring for cardiac device patients presenting with EMI.

  13. Monitoring the radiation dose to a multiprogrammable pacemaker during radical radiation therapy: A case report

    SciTech Connect

    Muller-Runkel, R.; Orsolini, G.; Kalokhe, U.P. )

    1990-11-01

    Multiprogrammable pacemakers, using complimentary metaloxide semiconductor (CMOS) circuitry, may fail during radiation therapy. We report about a patient who received 6,400 cGy for unresectable carcinoma of the left lung. In supine treatment position, arms raised above the head, the pacemaker was outside the treated area by a margin of at least 1 cm, shielded by cerrobend blocking mounted on a tray. From thermoluminescent dosimeter (TLD) measurements, we estimate that the pacemaker received 620 cGy in scatter doses. Its function was monitored before, during, and after completion of radiation therapy. The pacemaker was functioning normally until the patient's death 5 months after completion of treatment. The relevant electrocardiograms (ECGs) are presented.

  14. Torsade de pointes in a patient with complete atrioventricular block and pacemaker failure, misdiagnosed with epilepsy.

    PubMed

    Cai, Si-Yu; Ye, Shen-Feng; Wu, Xiang; Xiang, Mei-Xiang; Wang, Jian-An

    2015-01-01

    A case of torsade de pointes (TdP) with complete atrioventricular block and pacemaker failure that was misdiagnosed as epilepsy is presented herein. An 82-year-old female with recurrent seizure-like attacks showed epileptiform discharge during an electroencephalogram recording. A long QT interval and severe hypokalemia induced runs of TdP, which was related to pacemaker lead fracture, was detected during Holter recording and accompanied with episodes of seizures. After a DDD pacemaker with a new ventricular lead was replaced, there was no recurrence of any seizure-like attacks. Bradycardia-mediated TdP associated with complete atrioventricular block should not be missed in patients with recurrent seizure-like attacks even after pacemaker implantation.

  15. [Permanent pacemakers in children. The indications, complications and long-term follow-up].

    PubMed

    Camacho-Casillas, R; Vizcaíno-Alarcón, A; García-Hernández, N; Hurtado-del Río, D; Cerviño-Bárcena, L; Gordillo-Tobar, L

    1992-08-01

    Definitive pacemakers were placed in 27 children from June 1970 to October 1988. The indication for the pacemakers was congenital auriculoventricular block in 12 patients who were symptomatic; 8 were children with postoperative auriculoventricular block; 4 had developed complete auriculoventricular block from myocardiopathies and 3 from idiopathic sick-sinus syndrome. Two patients died: one 4 months after placement of the pacemaker due to unrelated causes, and the other 14 years later due to fracture of the electrode. There were 23 who were reoperated for different reasons but the most frequent was battery failure in 8 patients and pacemaker malfunction in 4 patients. The electrode was implanted in the epicardium in 21 patients and via subclavian vein into the endocardium in 6 cases. The growth and development physically and mentally were normal during the follow-up of these children. The average follow-up period was 55.6 months.

  16. 76 FR 53851 - Effective Date of Requirement for Premarket Approval for Cardiovascular Permanent Pacemaker...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-30

    ... proposed to require the filing of a premarket approval application or a notice of completion of a product development protocol for the class III preamendments device: Cardiovascular permanent pacemaker electrode....

  17. Understanding the timing cycles of a cardiac resynchronization device designed with left ventricular sensing.

    PubMed

    Barold, S Serge; Kucher, Andreas

    2014-10-01

    Some devices used for cardiac resynchronization therapy (CRT) can sense from the left ventricular (LV) lead as in Biotronik CRT devices (Biotronik GmbH, Berlin, Germany), whose special LV timing cycles form the basis of this report. LV sensing (LVs) was designed to prevent competitive pacing outside the LV myocardial absolute refractory period. LVs works by inhibiting the release of an LV pacemaker stimulus (LVp) in the vulnerable period of the LV during a programmable period. LVs with stored LV electrograms may also provide recordings of diagnostic value in tachyarrhythmias. LVs has added a new dimension to the evaluation of the function of CRT devices, because it is manifested by unfamiliar timing cycles. In this respect, Biotronik devices can initiate an LV upper rate interval (URI) upon sensing a right-sided event when LVs is turned off. An inhibited LVp can also initiate an LVURI. The LVURI should generally be programmed to a relatively short duration and shorter than the right ventricular URI to prevent a special form of desynchronization arrhythmia sustained by LVs. This arrhythmia is characterized by recurring delayed LVs events in sequences associated with RV pacing followed by LVs events with loss of LVp.

  18. Cardiac natriuretic peptides act via p38 MAPK to induce the brown fat thermogenic program in mouse and human adipocytes

    PubMed Central

    Bordicchia, Marica; Liu, Dianxin; Amri, Ez-Zoubir; Ailhaud, Gerard; Dessì-Fulgheri, Paolo; Zhang, Chaoying; Takahashi, Nobuyuki; Sarzani, Riccardo; Collins, Sheila

    2012-01-01

    The ability of mammals to resist body fat accumulation is linked to their ability to expand the number and activity of “brown adipocytes” within white fat depots. Activation of β-adrenergic receptors (β-ARs) can induce a functional “brown-like” adipocyte phenotype. As cardiac natriuretic peptides (NPs) and β-AR agonists are similarly potent at stimulating lipolysis in human adipocytes, we investigated whether NPs could induce human and mouse adipocytes to acquire brown adipocyte features, including a capacity for thermogenic energy expenditure mediated by uncoupling protein 1 (UCP1). In human adipocytes, atrial NP (ANP) and ventricular NP (BNP) activated PPARγ coactivator-1α (PGC-1α) and UCP1 expression, induced mitochondriogenesis, and increased uncoupled and total respiration. At low concentrations, ANP and β-AR agonists additively enhanced expression of brown fat and mitochondrial markers in a p38 MAPK–dependent manner. Mice exposed to cold temperatures had increased levels of circulating NPs as well as higher expression of NP signaling receptor and lower expression of the NP clearance receptor (Nprc) in brown adipose tissue (BAT) and white adipose tissue (WAT). NPR-C–/– mice had markedly smaller WAT and BAT depots but higher expression of thermogenic genes such as Ucp1. Infusion of BNP into mice robustly increased Ucp1 and Pgc-1α expression in WAT and BAT, with corresponding elevation of respiration and energy expenditure. These results suggest that NPs promote “browning” of white adipocytes to increase energy expenditure, defining the heart as a central regulator of adipose tissue biology. PMID:22307324

  19. Revisiting the reticulum: feedforward and feedback contributions to motor program parameters in the crab cardiac ganglion microcircuit

    PubMed Central

    García-Crescioni, Keyla

    2011-01-01

    The neurogenic heartbeat of crustaceans is controlled by the cardiac ganglion (CG), a central pattern generator (CPG) microcircuit composed of nine neurons. In most decapods, five “large” motor neurons (MNs) project from the CG to the myocardium, where their excitatory synaptic signals generate the rhythmic heartbeat. The processes of four “small” premotor neurons (PMNs) are confined to the CG, where they provide excitatory drive to the MNs via impulse-mediated chemical signals and electrotonic coupling. This study explored feedforward and feedback interactions between the PMNs and the MNs in the CG of the blue crab (Callinectes sapidus). Three methods were used to compare the activity of the MNs and the PMNs in the integrated CG to their autonomous firing patterns: 1) ligatures were tightened on the ganglion trunk that connects the PMNs and MNs; 2) TTX was applied focally to suppress selectively PMN or MN activity; and 3) sucrose pools were devised to block reversibly PMN or MN impulse conduction. With all treatments, the PMNs and MNs continued to produce autonomous rhythmic bursting following disengagement. Removal of PMN influence resulted in a significantly reduced MN duty cycle that was mainly attributable to a lower autonomous burst frequency. Conversely, after removal of MN feedback, the PMN duty cycle was increased, primarily due to a prolonged burst duration. Application of sucrose to block impulse conduction without eliminating PMN oscillations disclosed significant contributions of spike-mediated PMN-to-MN signals to the initiation and prolongation of the MN burst. Together, these observations support a view of the Callinectes CG composed of two classes of spontaneously bursting neurons with distinct endogenous rhythms. Compartmentalized feedforward and feedback signaling endow this microcircuit with syncytial properties such that the intrinsic attributes of the PMNs and MNs both contribute to shaping all parameters of the motor patterns

  20. Influence of He-Ne laser radiation of pacemaker on the frog's heart function

    NASA Astrophysics Data System (ADS)

    Porozov, Yury B.; Brill, Gregory E.; Kiritchuk, Vyacheslav F.

    1997-02-01

    In experiments on isolated amphibian hearts changes in photoreactivity of pacemaker cells under the influence of He-Ne laser radiation in different phases of the heart cycle were studied. The specificity of heart photoreaction, peculiarities of relaxation period after laser light action and laser modification of hypodynamic depression development were revealed. Adaptation of pacemaker cells to the He-Ne laser exposure was observed.

  1. In vivo powering of pacemaker by breathing-driven implanted triboelectric nanogenerator.

    PubMed

    Zheng, Qiang; Shi, Bojing; Fan, Fengru; Wang, Xinxin; Yan, Ling; Yuan, Weiwei; Wang, Sihong; Liu, Hong; Li, Zhou; Wang, Zhong Lin

    2014-09-03

    The first application of an implanted triboelectric nanogenerator (iTENG) that enables harvesting energy from in vivo mechanical movement in breathing to directly drive a pacemaker is reported. The energy harvested by iTENG from animal breathing is stored in a capacitor and successfully drives a pacemaker prototype to regulate the heart rate of a rat. This research shows a feasible approach to scavenge biomechanical energy, and presents a crucial step forward for lifetime-implantable self-powered medical devices.

  2. A fully implantable pacemaker for the mouse: from battery to wireless power.

    PubMed

    Laughner, Jacob I; Marrus, Scott B; Zellmer, Erik R; Weinheimer, Carla J; MacEwan, Matthew R; Cui, Sophia X; Nerbonne, Jeanne M; Efimov, Igor R

    2013-01-01

    Animal models have become a popular platform for the investigation of the molecular and systemic mechanisms of pathological cardiovascular physiology. Chronic pacing studies with implantable pacemakers in large animals have led to useful models of heart failure and atrial fibrillation. Unfortunately, molecular and genetic studies in these large animal models are often prohibitively expensive or not available. Conversely, the mouse is an excellent species for studying molecular mechanisms of cardiovascular disease through genetic engineering. However, the large size of available pacemakers does not lend itself to chronic pacing in mice. Here, we present the design for a novel, fully implantable wireless-powered pacemaker for mice capable of long-term (>30 days) pacing. This design is compared to a traditional battery-powered pacemaker to demonstrate critical advantages achieved through wireless inductive power transfer and control. Battery-powered and wireless-powered pacemakers were fabricated from standard electronic components in our laboratory. Mice (n = 24) were implanted with endocardial, battery-powered devices (n = 14) and epicardial, wireless-powered devices (n = 10). Wireless-powered devices were associated with reduced implant mortality and more reliable device function compared to battery-powered devices. Eight of 14 (57.1%) mice implanted with battery-powered pacemakers died following device implantation compared to 1 of 10 (10%) mice implanted with wireless-powered pacemakers. Moreover, device function was achieved for 30 days with the wireless-powered device compared to 6 days with the battery-powered device. The wireless-powered pacemaker system presented herein will allow electrophysiology studies in numerous genetically engineered mouse models as well as rapid pacing-induced heart failure and atrial arrhythmia in mice.

  3. Pacemaker lead malpositioning led to subsequent ischemic strokes despite antiplatelet and anticoagulation therapy

    PubMed Central

    2014-01-01

    Pacemaker lead malpositioning may lead to severe clinical adverse events. Rarely, cases of inadvertent placement of a lead into the left ventricle are reported in the literature. We herein report a case of pacemaker lead malpositioning into the left ventricle via a persistent foramen ovale in a male caucasian patient. After this procedural adverse event, the patient suffered from two ischemic strokes despite antiplatelet and anticoagulation therapy. PMID:24650169

  4. Mechanical wear of pacemaker lead insulation. A cause of loss of pacing.

    PubMed

    Kruse, I M; Mark, J; Rydén, L

    1980-03-01

    A pacemaker-treated patient is described in whom lead insulation defect caused sudden loss of capture. The defect was caused by mechanical wear of the posterior leaflet of the tricuspid valve and resulted in shunting of the pulse generator with a current drain exceeding the capacity of the pacemaker. In three further cases a similar explanation to sudden loss of pacing was highly suspected.

  5. Cardiac Conduction through Engineered Tissue

    PubMed Central

    Choi, Yeong-Hoon; Stamm, Christof; Hammer, Peter E.; Kwaku, Kevin F.; Marler, Jennifer J.; Friehs, Ingeborg; Jones, Mara; Rader, Christine M.; Roy, Nathalie; Eddy, Mau-Thek; Triedman, John K.; Walsh, Edward P.; McGowan, Francis X.; del Nido, Pedro J.; Cowan, Douglas B.

    2006-01-01

    In children, interruption of cardiac atrioventricular (AV) electrical conduction can result from congenital defects, surgical interventions, and maternal autoimmune diseases during pregnancy. Complete AV conduction block is typically treated by implanting an electronic pacemaker device, although long-term pacing therapy in pediatric patients has significant complications. As a first step toward developing a substitute treatment, we implanted engineered tissue constructs in rat hearts to create an alternative AV conduction pathway. We found that skeletal muscle-derived cells in the constructs exhibited sustained electrical coupling through persistent expression and function of gap junction proteins. Using fluorescence in situ hybridization and polymerase chain reaction analyses, myogenic cells in the constructs were shown to survive in the AV groove of implanted hearts for the duration of the animal’s natural life. Perfusion of hearts with fluorescently labeled lectin demonstrated that implanted tissues became vascularized and immunostaining verified the presence of proteins important in electromechanical integration of myogenic cells with surrounding recipient rat cardiomyocytes. Finally, using optical mapping and electrophysiological analyses, we provide evidence of permanent AV conduction through the implant in one-third of recipient animals. Our experiments provide a proof-of-principle that engineered tissue constructs can function as an electrical conduit and, ultimately, may offer a substitute treatment to conventional pacing therapy. PMID:16816362

  6. Pacemaker rate and depolarization block in nigral dopamine neurons: a somatic sodium channel balancing act

    PubMed Central

    Tucker, Kristal R.; Huertas, Marco A.; Horn, John P.; Canavier, Carmen C.; Levitan, Edwin S.

    2012-01-01

    Midbrain dopamine (DA) neurons are slow intrinsic pacemakers that undergo depolarization (DP) block upon moderate stimulation. Understanding DP block is important because it has been correlated with the clinical efficacy of chronic antipsychotic drug treatment. Here we describe how voltage-gated sodium (NaV) channels regulate DP block and pacemaker activity in DA neurons of the substantia nigra using rat brain slices. The distribution, density and gating of NaV currents were manipulated by blocking native channels with tetrodotoxin and by creating virtual channels and anti-channels with dynamic clamp. Although action potentials initiate in the axon initial segment (AIS) and NaV channels are distributed in multiple dendrites, selective reduction of NaV channel activity in the soma was sufficient to decrease pacemaker frequency and increase susceptibility to DP block. Conversely, increasing somatic NaV current density raised pacemaker frequency and lowered susceptibility to DP block. Finally, when NaV currents were restricted to the soma, pacemaker activity occurred at abnormally high rates due to excessive local subthreshold NaV current. Together with computational simulations, these data show that both the slow pacemaker rate and the sensitivity to DP block that characterizes DA neurons result from the low density of somatic NaV channels. More generally, we conclude that the somatodendritic distribution of NaV channels is a major determinant of repetitive spiking frequency. PMID:23077037

  7. Development of pacemaker properties and rhythmogenic mechanisms in the mouse embryonic respiratory network

    PubMed Central

    Chevalier, Marc; Toporikova, Natalia; Simmers, John; Thoby-Brisson, Muriel

    2016-01-01

    Breathing is a vital rhythmic behavior generated by hindbrain neuronal circuitry, including the preBötzinger complex network (preBötC) that controls inspiration. The emergence of preBötC network activity during prenatal development has been described, but little is known regarding inspiratory neurons expressing pacemaker properties at embryonic stages. Here, we combined calcium imaging and electrophysiological recordings in mouse embryo brainstem slices together with computational modeling to reveal the existence of heterogeneous pacemaker oscillatory properties relying on distinct combinations of burst-generating INaP and ICAN conductances. The respective proportion of the different inspiratory pacemaker subtypes changes during prenatal development. Concomitantly, network rhythmogenesis switches from a purely INaP/ICAN-dependent mechanism at E16.5 to a combined pacemaker/network-driven process at E18.5. Our results provide the first description of pacemaker bursting properties in embryonic preBötC neurons and indicate that network rhythmogenesis undergoes important changes during prenatal development through alterations in both circuit properties and the biophysical characteristics of pacemaker neurons. DOI: http://dx.doi.org/10.7554/eLife.16125.001 PMID:27434668

  8. The East Asian Summer Monsoon in pacemaker experiments driven by ENSO

    NASA Astrophysics Data System (ADS)

    Ding, Hui; Greatbatch, Richard; Lu, Jian

    2014-05-01

    The variability of the East Asian summer monsoon (EASM) is studied using a pacemaker technique in a atmospheric general circulation model (AGCM) coupled to a slab mixed layer model. In the pacemaker experiment, sea surface temperature (sst) is constrained to observations in the eastern equatorial Pacific throughout a q-flux that measures the contribution of ocean dynamics to SST variability, while the AGCM is still coupled to the slab model. An ensemble of pacemaker experiments is analysed using a multivariate EOF analysis to identify the two major modes of variability of the EASM. Results show that the pacemaker experiments simulate part of the variability of the first mode seen in the ERA40 reanalysis (correlation up to 0.67 for the model ensemble mean), as expected. Different from previous study, the pacemaker experiments also simulate part of the variabilty (correlation up to 0.51 for the model ensemble mean) of the second mode, a mode of variability that is related to that of the Indian Summer Monsoon. A possible reason is the success of the pacemaker experiments at reproducing the relationship between El Nino Southern Oscillation (ENSO) and the second mode of EASM.

  9. The East Asian Summer Monsoon in pacemaker experiments driven by ENSO

    NASA Astrophysics Data System (ADS)

    Ding, Hui; Greatbatch, Richard J.; Lu, Jian; Cash, Ben

    2015-03-01

    The variability of the East Asian summer monsoon (EASM) is studied using a pacemaker technique driven by ENSO in an atmospheric general circulation model (AGCM) coupled to a slab mixed layer model. In the pacemaker experiments, sea surface temperature (SST) is constrained to observations in the eastern equatorial Pacific through a q- flux that measures the contribution of ocean dynamics to SST variability, while the AGCM is coupled to the slab model. An ensemble of pacemaker experiments is analyzed using a multivariate EOF analysis to identify the two major modes of variability of the EASM. The results show that the pacemaker experiments simulate a substantial amount (around 45 %) of the variability of the first mode (the Pacific-Japan pattern) in ERA40 from 1979 to 1999. Different from previous work, the pacemaker experiments also simulate a large part (25 %) of the variability of the second mode, related to rainfall variability over northern China. Furthermore, we find that the lower (850 hPa) and the upper (200 hPa) tropospheric circulation of the first mode display the same degree of reproducibility whereas only the lower part of the second mode is reproducible. The basis for the success of the pacemaker experiments is the ability of the experiments to reproduce the observed relationship between El Niño Southern Oscillation (ENSO) and the EASM.

  10. Effects of thallium on membrane currents at diastolic potentials in canine cardiac Purkinje strands.

    PubMed Central

    Cohen, I S; Mulrine, N K

    1986-01-01

    A two-micro-electrode voltage-clamp technique was used to record membrane currents from canine cardiac Purkinje strands during hyperpolarizing steps to potentials between -70 and -150 mV in Tyrode solutions containing K+ and/or Tl+. Complete replacement of external K+ by equimolar Tl+ increases the instantaneous inwardly rectifying current. The inwardly rectifying region of the instantaneous I-V relation is shifted to more positive potentials and its slope is increased. The diastolic time-dependent current is reduced or reversed. Partial substitution of equimolar Tl+ for K+ reduces the diastolic time-dependent current. The instantaneous I-V relation is shifted inward for molar fractions of Tl+ (YTl) greater than 0.5, and is slightly more inward or unchanged for YTl less than or equal to 0.5. Addition of small amounts of Tl+ shifts the instantaneous I-V relation inward and reduces the diastolic time-dependent current. Addition of Tl+ in solutions containing Ba2+ to block the background inward rectifier has no effect on the instantaneous I-V relation; the diastolic time-dependent (pace-maker) current is reduced. Block of the pace-maker current by Tl+ is largely independent of potential in Ba2+ Tyrode solution. Since Tl+ has opposite effects on the pace-maker current and the inward rectifier, these findings support other evidence that the pace-maker current is not part of the background inward rectifier. PMID:2420975

  11. Is metabolic rate a universal 'pacemaker' for biological processes?

    PubMed

    Glazier, Douglas S

    2015-05-01

    A common, long-held belief is that metabolic rate drives the rates of various biological, ecological and evolutionary processes. Although this metabolic pacemaker view (as assumed by the recent, influential 'metabolic theory of ecology') may be true in at least some situations (e.g. those involving moderate temperature effects or physiological processes closely linked to metabolism, such as heartbeat and breathing rate), it suffers from several major limitations, including: (i) it is supported chiefly by indirect, correlational evidence (e.g. similarities between the body-size and temperature scaling of metabolic rate and that of other biological processes, which are not always observed) - direct, mechanistic or experimental support is scarce and much needed; (ii) it is contradicted by abundant evidence showing that various intrinsic and extrinsic factors (e.g. hormonal action and temperature changes) can dissociate the rates of metabolism, growth, development and other biological processes; (iii) there are many examples where metabolic rate appears to respond to, rather than drive the rates of various other biological processes (e.g. ontogenetic growth, food intake and locomotor activity); (iv) there are additional examples where metabolic rate appears to be unrelated to the rate of a biological process (e.g. ageing, circadian rhythms, and molecular evolution); and (v) the theoretical foundation for the metabolic pacemaker view focuses only on the energetic control of biological processes, while ignoring the importance of informational control, as mediated by various genetic, cellular, and neuroendocrine regulatory systems. I argue that a comprehensive understanding of the pace of life must include how biological activities depend on both energy and information and their environmentally sensitive interaction. This conclusion is supported by extensive evidence showing that hormones and other regulatory factors and signalling systems coordinate the processes of

  12. Phentolamine inhibits the pacemaker activity of mouse interstitial cells of Cajal by activating ATP-sensitive K+ channels.

    PubMed

    Ahn, Seung Whan; Kim, Sang Hun; Kim, Jin Ho; Choi, Seok; Yeum, Cheol Ho; Wie, Hee Wook; Sun, Jae Myeong; So, Insuk; Jun, Jae Yeoul

    2010-03-01

    The aim of this study was to clarify if phentolamine has proven effects on the pacemaker activities of interstitial cells of Cajal (ICC) from the mouse small intestine involving the ATPsensitive K(+) channels and adrenergic receptor. The actions of phentolamine on pacemaker activities were investigated using whole-cell patch-clamp technique and intracellular Ca(2+) analysis at 30 degrees C in cultured mouse intestinal ICC. ICC generated spontaneous pacemaker currents at a holding potential of -70 mV. Treatment with phentolamine reduced the frequency and amplitude of the pacemaker currents and increased the resting outward currents. Moreover, under current clamping (I = 0), phentolamine hyperpolarized the ICC membrane and decreased the amplitude of the pacemaker potentials. We also observed that phentolamine inhibited spontaneous [Ca(2+)](i) oscillations in ICC. The alpha-adrenergic drugs prazosin, yohimbine, methoxamine, and clonidine had no effect on ICC intestinal pacemaker activity and did not block phentolamine-induced effects. Phentolamine-induced effects on the pacemaker currents and the pacemaker potentials were significantly inhibited by ATP sensitive K(+) channel blocker glibenclamide, but not by TEA, apamin, or 4-aminopyridine. In addition, the NO synthase inhibitor, L-NAME and the guanylate cyclase inhibitor, ODQ were incapable of blocking the phentolamine-induced effects. These results demonstrate that phentolamine regulates the pacemaker activity of ICC via ATP-sensitive K(+) channel activation. Phentolamine could act through an adrenergic receptor- and also through NO-independent mechanism that involves intracellular Ca(2+) signaling.

  13. Quasiperiodicity route to chaos in cardiac conduction model

    NASA Astrophysics Data System (ADS)

    Quiroz-Juárez, M. A.; Vázquez-Medina, R.; Ryzhii, E.; Ryzhii, M.; Aragón, J. L.

    2017-01-01

    It has been suggested that cardiac arrhythmias are instances of chaos. In particular that the ventricular fibrillation is a form of spatio-temporal chaos that arises from normal rhythm through a quasi-periodicity or Ruelle-Takens-Newhouse route to chaos. In this work, we modify the heterogeneous oscillator model of cardiac conduction system proposed in Ref. [Ryzhii E, Ryzhii M. A heterogeneous coupled oscillator model for simulation of ECG signals. Comput Meth Prog Bio 2014;117(1):40-49. doi:10.1016/j.cmpb.2014.04.009.], by including an ectopic pacemaker that stimulates the ventricular muscle to model arrhythmias. With this modification, the transition from normal rhythm to ventricular fibrillation is controlled by a single parameter. We show that this transition follows the so-called torus of quasi-periodic route to chaos, as verified by using numerical tools such as power spectrum and largest Lyapunov exponent.

  14. Cardiac optogenetics

    PubMed Central

    2013-01-01

    Optogenetics is an emerging technology for optical interrogation and control of biological function with high specificity and high spatiotemporal resolution. Mammalian cells and tissues can be sensitized to respond to light by a relatively simple and well-tolerated genetic modification using microbial opsins (light-gated ion channels and pumps). These can achieve fast and specific excitatory or inhibitory response, offering distinct advantages over traditional pharmacological or electrical means of perturbation. Since the first demonstrations of utility in mammalian cells (neurons) in 2005, optogenetics has spurred immense research activity and has inspired numerous applications for dissection of neural circuitry and understanding of brain function in health and disease, applications ranging from in vitro to work in behaving animals. Only recently (since 2010), the field has extended to cardiac applications with less than a dozen publications to date. In consideration of the early phase of work on cardiac optogenetics and the impact of the technique in understanding another excitable tissue, the brain, this review is largely a perspective of possibilities in the heart. It covers the basic principles of operation of light-sensitive ion channels and pumps, the available tools and ongoing efforts in optimizing them, overview of neuroscience use, as well as cardiac-specific questions of implementation and ideas for best use of this emerging technology in the heart. PMID:23457014

  15. Cardiac Surgery

    PubMed Central

    Weisse, Allen B.

    2011-01-01

    Well into the first decades of the 20th century, medical opinion held that any surgical attempts to treat heart disease were not only misguided, but unethical. Despite such reservations, innovative surgeons showed that heart wounds could be successfully repaired. Then, extracardiac procedures were performed to correct patent ductus arteriosus, coarctation of the aorta, and tetralogy of Fallot. Direct surgery on the heart was accomplished with closed commissurotomy for mitral stenosis. The introduction of the heart-lung machine and cardiopulmonary bypass enabled the surgical treatment of other congenital and acquired heart diseases. Advances in aortic surgery paralleled these successes. The development of coronary artery bypass grafting greatly aided the treatment of coronary heart disease. Cardiac transplantation, attempts to use the total artificial heart, and the application of ventricular assist devices have brought us to the present day. Although progress in the field of cardiovascular surgery appears to have slowed when compared with the halcyon times of the past, substantial challenges still face cardiac surgeons. It can only be hoped that sufficient resources and incentive can carry the triumphs of the 20th century into the 21st. This review covers past developments and future opportunities in cardiac surgery. PMID:22163121

  16. Incidence and Risk Factors for and the Effect of a Program To Reduce the Incidence of Surgical Site Infection after Cardiac Surgery

    PubMed Central

    Cohen, Bevin; Hyman, Sandra; Larson, Elaine; Fowler, Dennis L.

    2014-01-01

    Abstract Background: Surgical site infection (SSI) after cardiac surgery (CS) is a serious complication that increases hospital length of stay (LOS), has a substantial financial impact, and increases mortality. The study described here was done to evaluate the effect of a program to reduce SSI after CS. Methods: In January 2007, a multi-disciplinary CS infection-prevention team developed guidelines and implemented bundled tactics for reducing SSI. Data for all patients who underwent CS from 2006–2008 were used to determine whether there was: 1) A difference in the incidence of SSI in white patients and those belonging to minority groups; 2) a reduction in SSI after intervention; and 3) a statistically significant difference in the incidence of SSI in the third quarter of each year as compared with the other quarters of the year. Results: Of 3,418 patients who underwent CS; 1,125 (32.9%) were members of minority groups and 2,293 (67.1%) were white. Eighty (2.3%) patients developed SSI. There was no significant difference in the incidence of SSI in non-Hispanic white patients and all others (2.1% vs. 2.8%, p=0. 42). The incidence of SSI decreased significantly from 2006 (3.0%) to 2007 (2.5%) and 2008 (1.4%), (p=0.03). Surgical site infection occurred more often in the third quarter of each of the years of the study than in other quarters of each year (3.3 vs. 2.0%, p=0.038). Conclusions: Implementation of a program to reduce SSI after CS was associated with a lower incidence of SSI across all racial and ethnic groups and over time, but was not associated with a lower incidence of SSI in the third quarter of each year than in the other quarters. PMID:24800982

  17. Treatment of the Aged Patients at a Large Cardiac Rehabilitation Center in the Southern Brazil and Some Aspects of Their Dropout from the Therapeutic Programs

    PubMed Central

    Nesello, Pietro Felice Tomazini; Tairova, Olga; Tairova, Maria; Graciolli, Lucas; Baroni, Allan; Comparsi, Eduardo; Marchi, Thiago De

    2016-01-01

    AIM: This paper aims to assess the dropout rate in different age groups through the example of the large cardiac rehabilitation centre affiliated with the Institute of Sports Medicine, University of Caxias do Sul. MATERIAL AND METHODS: A historic cohort study comprising the following groups: Non-Old < 65 (n = 141); Young-Old 65-74 (n = 128); and Middle-Old 75-84 years old (n = 57). The exercise program lasted 48 sessions and dropout was defined as attendance of 50% of sessions or less. Logistic binominal regression was performed to assess the risk of dropout. For all analyses, a two-tailed P value of < 0.05 was used. RESULTS: The total dropout rate was 38.6%. The Young-Old and Middle-Old groups showed lower dropouts compared to Non-Old patients (p = 0.01). Young-Old has 96% less risk for dropout compared to Non-Old group (adjusted odds ratios = 1.96 [1.16–3.29]). Furthermore, patients underwent the Coronary Artery Bypass Graft showed a lower rate of dropout (p = 0.001). The absence of CABG involved three times more risk of dropout (p = 0.001). CONCLUSION: The Non-Old and the Middle-Old patients showed higher dropout rates compared to Young-Old. To ensure the best possible rehabilitation and to improve patients´ participation in CR, these programs should be adjusted to the needs of patients in terms of their age. PMID:28028408

  18. Underdiagnosis of Conditions Associated with Sudden Cardiac Death in Children--Is it the Absence of a Comprehensive Screening Program or a True Low Prevalence?

    PubMed

    Takiguchi, Marisa; Knight, Tristan; Nguyen, Tin Toan; Limm, Blair; Hayes, Donald; Reddy, Venu; Bratincsak, Andras

    2016-02-01

    This study aimed to assess the prevalence of conditions associated with sudden cardiac death (SCD) among all children and children with sudden infant death syndrome (SIDS) in the State of Hawai'i, where no comprehensive screening program is conducted for such conditions. A retrospective chart review was conducted from the single tertiary pediatric hospital in Hawai'i, from offices of all pediatric cardiologists in Hawai'i, and the Hawai'i State Department of Health from 1/1/2000 to 12/31/2013. Children aged 0-18 years were included in the study. A subset of the study analyzed records of infants aged 0-12 months. SIDS rate was calculated and compared to national data. Prevalence was calculated for known conditions associated with SCD. The identified prevalence was compared to the established prevalence of conditions associated with SCD. In Hawai'i, the infant SIDS rate (66.4/100,000) was similar to the national rate (54.4/100,000). Over 14 years, only 51 children were diagnosed with a condition associated with SCD; 28 with a cardiomyopathy and 21 with a channelopathy. A 14-year retrospective analysis in the State of Hawai'i revealed that less than 1 in 30 children, who are expected to harbor a SCD-associated condition, had been appropriately diagnosed. The underdiagnosis of conditions associated with SCD reflects that in the absence of a comprehensive screening program, conditions without obvious signs and symptoms are difficult to diagnose. Many children with these conditions will remain at risk of SCD.

  19. Clinical applications of magnets on cardiac rhythm management devices.

    PubMed

    Jacob, Sony; Panaich, Sidakpal S; Maheshwari, Rahul; Haddad, John W; Padanilam, Benzy J; John, Sinoj K

    2011-09-01

    The growing indications for permanent pacemaker and implantable cardioverter defibrillator (ICD) implantation have increased the number of patients with these cardiac rhythm management devices (CRMDs). Cardiac rhythm management devices occasionally perform inappropriately in response to electromagnetic interference (e.g. surgical electrocautery) or lead noise over-sensing (e.g. lead fracture). Temporary reprogramming of the CRMDs using device programmers can prevent these untoward device responses. However, these programmers are device manufacturer specific and require technically qualified personnel to operate. This could cause delayed patient care and increased use of resources in certain clinical situations. Alternatively, clinical magnets, when appropriately positioned over the device site, can change the pacing to an asynchronous mode in pacemakers and suspend tachycardia therapies in ICDs. Although readily available, clinical magnets have not been widely used for this purpose, perhaps due to the unfamiliarity with the variable responses of CRMDs to magnet application. This article provides a comprehensive overview of the current literature on the mechanism of action and the specific responses of various CRMDs to clinical magnets.

  20. Ectopic jejunal pacemakers and gastric emptying after Roux gastrectomy: Effect of intestinal pacing

    SciTech Connect

    Karlstrom, L.; Kelly, K.A. )

    1989-11-01

    The aims of this study were to determine whether ectopic pacemakers are present after meals in the Roux limbs of dogs after vagotomy and Roux gastrectomy, whether these pacemakers slow gastric emptying of liquids or solids, and whether abolishing the pacemakers with electric pacing might speed any slow emptying that occurs. In six dogs that underwent vagotomy and Roux gastrectomy and in four dogs that underwent vagotomy and Billroth gastrectomy (controls), myoelectric activity of the Roux limb or duodenum was measured during gastric emptying of a 500 kcal mixed meal of 99mTc-labeled cooked egg and 111In-labeled milk. Roux dogs were tested with and without pacing of the Roux limb. Roux dogs showed ectopic pacemaker in the Roux limb that drove the pacesetter potentials of the limb in a reverse, or orad, direction during 57% of the postprandial recordings. Billroth dogs had no ectopic pacemakers (p less than 0.05). Liquids emptied more slowly in Roux dogs (half-life (t1/2) = 121 +/- 15 minutes) than in Billroth dogs (t1/2 = 43 +/- 9 minutes; p less than 0.05), but solids emptied similarly in both groups of dogs (t1/2 approximately 8 hours). Pacing the Roux limb abolished the ectopic pacemakers, restored the slow emptying of liquids to the more rapid rate found in the Billroth dogs (t1/2: paced Roux, 72 +/- 15 minutes; Billroth, 43 +/- 9 minutes; p greater than 0.05) and did not change emptying of solids. The conclusion was that ectopic pacemakers present in the Roux limb after vagotomy and Roux gastrectomy drove the limb in a reverse direction and slowed emptying of liquids after the operation. The defect was corrected by pacing the Roux limb in a forward direction.