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Sample records for cardiac pacemaker program

  1. [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. PMID:26227982

  2. 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

  3. 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.

  4. 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

  5. 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.

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

    NASA Astrophysics Data System (ADS)

    Borek, Bart?omiej; 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.

  7. 21 CFR 870.5550 - External transcutaneous cardiac pacemaker (noninvasive).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Therapeutic Devices § 870.5550 External transcutaneous cardiac pacemaker (noninvasive)....

  8. Permanent cardiac pacemaker in infants and children.

    PubMed

    Dasmahapatra, H K; Jamieson, M P; Brewster, G M; Doig, B; Pollock, J C

    1986-08-01

    Between October 1970 and November 1984, 26 infants and children aged 11 days to 18 years (mean 5.7 years) received 42 permanent cardiac pacemakers (26 primary implants, 16 re-implants) for congenital or surgically acquired heart block, bradycardia and sinus node dysfunction. Twenty-two patients had unipolar pacing and 4 bipolar pacing. Of 26 primary implantations, 2 had fixed rate epicardial pacing, 16 ventricular demand pacing (13 epicardial, 3 endocardial), 3 epicardial VAT (P-synchronous) pacing and 5 DDD (universal) pacing (4 epicardial, one endocardial). Fourteen patients required a further 19 operations for change of generators (16), ventricular lead (1), generator site (1) and generator encasing (1). Thirty-day hospital mortality was 11.5% (3/26), of which one death was possibly related to pacing failure. Four patients died during the follow-up period (3 months to 10 years; mean 3.4 years). Sixteen of the 19 survivors achieved complete symptomatic relief, without any medical therapy. Our results indicate that modern cardiac pacemaker systems are safe and reliable, and are associated with major relief of symptoms in this age group. PMID:2429390

  9. 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

  10. 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.

  11. 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. PMID:24823380

  12. Purchase and design preferences for cardiac pacemakers.

    PubMed

    Shrivastav, M

    2001-11-01

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

  13. Magnetic interference of cardiac pacemakers from a surgical magnetic drape.

    PubMed

    Zaphiratos, Valerie; Donati, Francois; Drolet, Pierre; Bianchi, Andrea; Benzaquen, Bruno; Lapointe, Jacques; Fortier, Louis-Philippe

    2013-03-01

    Sterile magnetic drapes are frequently used during surgery to hold metal instruments on the sterile field. Magnetic fields may potentially interfere with the function of cardiovascular implantable electronic devices such as pacemakers and implantable cardioverter defibrillators. In this study, we evaluated the potential magnetic interference of magnetic drapes on pacemaker function. A magnetic drape with 70 magnets was placed with its approximate center over the pacemaker of 50 patients during their visit to the cardiology clinic. In those pacemakers that demonstrated magnetic interference, the drape was pulled caudally in 3-cm increments until the interference ceased. If there was no interference, the drape was folded in 2 over the pacemaker. The number of magnets necessary to maintain magnetic interference with the pacemaker was also tested. Magnetic interference was observed in the pacemakers of 47 (94%) patients: 35 with the unfolded drape and another 12 with the folded drape. Patients whose pacemakers had interference with the unfolded drape weighed less (68 ± 15 kg vs 81 ± 19 kg; P = 0.016) than those who had no interference. In 54% of patients, magnetic interference ceased when the drape was pulled 3 cm caudally and at 15 cm, no pacemaker had magnetic interference. Magnetic drapes may cause magnetic interference with cardiac pacemakers, and this interference ceases at a caudal distance of 15 cm. Magnetic interference seems more likely in patients with lower body weight. Careful monitoring of the pulse and electrocardiogram for asynchronous pacing activity should be considered when magnetic drapes are used in patients with cardiovascular implantable electronic devices. PMID:23400981

  14. Cardiac pacemakers and electrocautery in ophthalmic surgery.

    PubMed

    Peter, Neena M; Ribes, Pura; Khooshabeh, Ramona

    2012-12-01

    The aging of the population and our ability to care for a patient with increasingly complex disease suggest that we will be caring for many more patients with pacemakers and implantable cardioverter-defibrillators. Using surgical diathermy or electrocautery on these patientscan present the additional risk of electrical interference and appropriate precautions need to be considered. We summarise the different type of pacemakers and electrocautery, and how electrocautery can interfere with such devices. We discuss the relevant issues that should be considered when these patients undergo assessment for surgery and their intra- and post-operative management, including the use of magnets. PMID:23061664

  15. Automated Verification of Quantitative Properties of Cardiac Pacemaker Software

    E-print Network

    Oxford, University of

    , such as cardiac pacemakers [6], GPCA infusion pumps [8] and continuous glucose monitors [11], are stochastic hybrid systems: they involve discrete mode switching and nonlinear continuous flows, e.g., electrical signal or glucose level, while at the same time allowing for stochasticity that arises from randomness

  16. 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...

  17. Generation of murine cardiac pacemaker cell aggregates based on ES-cell-programming in combination with Myh6-promoter-selection.

    PubMed

    Rimmbach, Christian; Jung, Julia J; David, Robert

    2015-01-01

    Treatment of the "sick sinus syndrome" is based on artificial pacemakers. These bear hazards such as battery failure and infections. Moreover, they lack hormone responsiveness and the overall procedure is cost-intensive. "Biological pacemakers" generated from PSCs may become an alternative, yet the typical content of pacemaker cells in Embryoid Bodies (EBs) is extremely low. The described protocol combines "forward programming" of murine PSCs via the sinus node inducer TBX3 with Myh6-promoter based antibiotic selection. This yields cardiomyocyte aggregates consistent of >80% physiologically functional pacemaker cells. These "induced-sinoatrial-bodies" ("iSABs") are spontaneously contracting at yet unreached frequencies (400-500 bpm) corresponding to nodal cells isolated from mouse hearts and are able to pace murine myocardium ex vivo. Using the described protocol highly pure sinus nodal single cells can be generated which e.g. can be used for in vitro drug testing. Furthermore, the iSABs generated according to this protocol may become a crucial step towards heart tissue engineering. PMID:25742394

  18. Materials aspects of implantable cardiac pacemaker leads.

    PubMed

    Bruck, S D; Mueller, E P

    1988-01-01

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

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

    PubMed

    Šnorek, Michal; Bulava, Alan

    2014-02-01

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

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

    PubMed Central

    2015-01-01

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

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

    PubMed

    Vlk, J; Vincenzi, F F

    1977-01-01

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

  2. 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.

  3. 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 ...

  4. 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.

  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. PMID:20360143

  6. Possible Influences of Spark Discharges on Cardiac Pacemakers.

    PubMed

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

    2016-01-01

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

  7. 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.

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

    PubMed

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

    2002-09-01

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

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

    PubMed Central

    Chung, Mee Young; Chae, Su Min

    2015-01-01

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

  10. 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; Viš?or, 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.

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

    PubMed

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

    2014-07-23

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

  12. Functional Role of CLC-2 Chloride Inward Rectifier Channels in Cardiac Sinoatrial Nodal Pacemaker Cells

    PubMed Central

    Huang, Z. Maggie; Prasad, Chaithra; Britton, Fiona C.; Ye, Linda L.; Hatton, William J.; Duan, Dayue

    2009-01-01

    A novel Cl? inward rectifier channel (Cl,ir) encoded by ClC-2, a member of the ClC voltage-gated Cl? channel gene superfamily, has been recently discovered in cardiac myocytes of several species. However, the physiological role of Cl,ir channels in the heart remains unknown. In this study we tested the hypothesis that Cl,ir channels may play an important role in cardiac pacemaker activity. In isolated guinea-pig sinoatrial node (SAN) cells, Cl,ir current was activated by hyperpolarization and hypotonic cell swelling. RT-PCR and immunohistological analyses confirmed the molecular expression of ClC-2 in guinea-pig SAN cells. Hypotonic stress increased the diastolic depolarization slope and decreased the maximum diastolic potential, action potential amplitude, APD50, APD90, and the cycle-length of the SAN cells. These effects were largely reversed by intracellular dialysis of anti-ClC-2 antibody, which significantly inhibited Cl,ir current but not other pacemaker currents, including the hyperpolarization-activated non-selective cationic “funny” current (If), the L-type Ca2+ currents (ICa,L), the slowly-activating delayed rectifier IKs and the volume-regulated outwardly-rectifying Cl? current (ICl,vol). Telemetry electrocardiograph studies in conscious ClC-2 knockout (Clcn2?/?) mice revealed a decreased chronotropic response to acute exercise stress when compared to their age-matched Clcn2+/+ and Clcn2+/? littermates. Targeted inactivation of ClC-2 does not alter intrinsic heart rate but prevented the positive chronotropic effect of acute exercise stress through a sympathetic regulation of ClC-2 channels. These results provide compelling evidence that ClC-2-encoded endogenous Cl,ir channels may play an important role in the regulation of cardiac pacemaker activity, which may become more prominent under stressed or pathological conditions. PMID:19376127

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

    PubMed Central

    Li, Yanping; Liao, Derong; Yang, Ling

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

    Objectives: To validate the physical and psychological effectiveness of cardiac pacing in pediatric patients with breath-holding spells (BHS) and prolonged asystole. Materials and Methods: The records and clinical data of all the patients with BHS who presented to our center in the period of 2001–2013 were reviewed. All patients who received cardiac pacemaker implantation for prolonged asystole during BHS were included. In addition, the parents were asked to fill out a standardized quality of life (QOL) questionnaire. Results: Seven patients were identified. The mean onset of symptoms was 7 month (1–12 months) of age, documented asystole was 12–21 seconds, and a permanent cardiac pacemaker device was implanted at a mean age of 23 months (8 months–3.9 years). No pacemaker related adverse events were recorded. Follow up showed immediate resolution from spells in four cases (4/7). Two patients (2/7) showed significant reduction of frequency and severity of spells, with complete elimination of loss of consciousness (LOC). One patient (1/7) with an additional neurologic disorder continued to have minor pallid BHS and eventually switched from pallid to cyanotic spells without further detection of bradycardia or asystole in holter examination. QOL questionnaire revealed significant reduction in subjective stress levels of patients (P = 0.012) and parents (P = 0.007) after pacemaker implantation. Conclusion: Cardiac pacing using appropriate pacemaker settings seems effective in the prevention of LOC and reduction of the frequency of BHS. Our results imply a reduction of subjective stress levels of patients and parents as well as an increased quality of everyday life. After all, randomized controlled trials of the influence of cardiac pacemaker implantation on subjective stress levels in patients with BHS are needed. PMID:26085761

  15. Cardiac pacemakers in magnetic fields of a shunt reactor at a 400?kV substation.

    PubMed

    Korpinen, Leena; Kuisti, Harri; Tarao, Hiroo; Elovaara, Jarmo; Virtanen, Vesa

    2015-01-01

    The use of cardiac pacemakers (PMs) increases in Western countries. The aim of the study is to investigate cardiac pacemakers (PMs) using a human-shaped phantom in magnetic fields of a shunt reactor at a 400?kV substation. We performed seven PM experiments using a phantom. Two locations close to the shunt reactors were chosen. The magnetic field exposure was over 1000 µT in one location and over 600 µT in the other one. The magnetic field exposure did not disturb the tested five different PMs (in unipolar or bipolar configurations). It can be stated that in our experiment, the magnetic field exposure (over 600 µT and over 1000 µT) did not disturb the PMs (in unipolar or bipolar configurations). Since we only studied some PMs, it is possible that the magnetic field exposure at 400?kV substations can cause disturbances to other PMs. However, the risk of disturbances does not seem to be high. PMID:26323783

  16. 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.

  17. Profile of St. Jude Medical's Allure Quadra quadripolar pacemaker system for cardiac resynchronization therapy.

    PubMed

    Corbisiero, Raffaele; Muller, David

    2015-01-01

    Congestive heart failure is a major public health epidemic and economic burden in the USA and worldwide. Cardiac resynchronization therapy is an effective therapy for treating congestive heart failure in conjunction with pharmacologic therapy. The average congestive heart failure admission costs approximately US$ 8 billion annually. Current cardiac resynchronization therapy pacemaker systems from various manufacturers deliver therapy-utilizing bipolar leads including the left ventricle, with electrode spacing ranging from 8 to 22 mm. The Quartet LV™ lead model 1458Q (St. Jude Medical Sylmar, CA) is a quadripolar lead with a 4.0 Fr. tip electrode and three 4.7 Fr. ring electrodes located 20, 30 and 47 mm from the tip. The Quartet lead and Allure Quadra TM allows 14 pacing configurations, providing benefits, including reductions in phrenic nerve stimulation, reduced pacing thresholds, improved battery longevity and potential reductions, in non-responders to cardiac resynchronization therapy. In addition, there is cost benefit data from utilizing quadripolar technology compared with traditional bipolar cardiac resynchronization therapy. PMID:25418543

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

    PubMed Central

    2011-01-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2007-12-01

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

  1. [Reproducible ventricular flutter during programming of a DDD pacemaker].

    PubMed

    Bienstein, B; Grosse-Heitmeyer, W; Liebetrau, M; Stauff, L

    1993-12-23

    A bipolar DDD pacemaker system was implanted in a 51-year-old woman with a 2 degrees (Mobitz type) atrioventricular block. The first postimplantation control was unremarkable, but she collapsed 9 weeks later with dyspnoea, tachycardia and profound perspiration. Ventricular flutter occurred twice during routine ambulatory pacemaker function tests one week later. The first episode was terminated by a precordial blow with a fist, but the second required electrical defibrillation. During the subsequent hospitalization abnormal electrolyte balance and digitalis intoxication were excluded. Left-heart catheterization with coronary angiography showed normal left-ventricular function at rest and normal coronary arteries. There was no evidence for an arrhythmogenic right ventricle. Electrophysiological testing with programmed ventricular stimulation provoked ventricular tachycardia with torsade de pointes and transition to ventricular fibrillation. Antiarrhythmic treatment with sotalol, 160 mg twice daily by mouth, failed to suppress the episodes of torsade de pointes. But further programmed ventricular stimulation was uneventful after the sotalol dosage had been increased to 160 mg three times daily. PMID:8287779

  2. 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. PMID:23589888

  3. 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.

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

    PubMed Central

    Quinn, T. Alexander; Kohl, Peter

    2012-01-01

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

  5. How Does a Pacemaker Work?

    MedlinePLUS

    ... the NHLBI on Twitter. How Does a Pacemaker Work? A pacemaker consists of a battery, a computerized ... these recordings to adjust your pacemaker so it works better for you. Your doctor can program the ...

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed Central

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

    2013-01-01

    Whether intracellular Ca2+ cycling dynamics regulate cardiac pacemaker cell function on a beat-to-beat basis remains unknown. Here we show that under physiological conditions, application of low concentrations of caffeine (2–4 mM) to isolated single rabbit sinoatrial node cells acutely reduces their spontaneous action potential cycle length (CL) and increases Ca2+ transient amplitude for several cycles. Numerical simulations, using a modified Maltsev-Lakatta coupled-clock model, faithfully reproduced these effects, and also the effects of CL prolongation and dysrhythmic spontaneous beating (produced by cytosolic Ca2+ buffering) and an acute CL reduction (produced by flash-induced Ca2+ release from a caged Ca2+ buffer), which we had reported previously. Three contemporary numerical models (including the original Maltsev-Lakatta model) failed to reproduce the experimental results. In our proposed new model, Ca2+ releases acutely change the CL via activation of the Na+/Ca2+ exchanger current. Time-dependent CL reductions after flash-induced Ca2+ releases (the memory effect) are linked to changes in Ca2+ available for pumping into sarcoplasmic reticulum which, in turn, changes the sarcoplasmic reticulum Ca2+ load, diastolic Ca2+ releases, and Na+/Ca2+ exchanger current. These results support the idea that Ca2+ regulates CL in cardiac pacemaker cells on a beat-to-beat basis, and suggest a more realistic numerical mechanism of this regulation. PMID:24094396

  8. A migrating pacemaker

    PubMed Central

    Gale, C; Mulley, G

    2005-01-01

    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. PMID:15749800

  9. Pacemakers and Implantable Defibrillators

    MedlinePLUS

    ... a cardiac pacemaker or an implantable cardioverter defibrillator (ICD). They are devices that are implanted in your ... and coordinate the chambers of the heart. An ICD monitors heart rhythms. If it senses dangerous rhythms, ...

  10. [Sport for pacemaker patients].

    PubMed

    Israel, C W

    2012-06-01

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

  11. 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

  12. 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.

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

    PubMed

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

    2015-04-01

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

  14. Women's compliance with cardiac rehabilitation programs.

    PubMed

    Ginzel, A R

    1996-01-01

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

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

    PubMed Central

    Maltsev, Victor A.; Lakatta, Edward G.

    2015-01-01

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

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

    PubMed Central

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

    2012-01-01

    Background Mitochondria dynamically buffer cytosolic Ca2+ in cardiac ventricular cells and this affects the Ca2+ load of the sarcoplasmic reticulum (SR). In sinoatrial-node cells (SANC) the SR generates periodic local, subsarcolemmal Ca2+ releases (LCRs) that depend upon the SR load and are involved in SANC automaticity: LCRs activate an inward Na+-Ca2+ exchange current to accelerate the diastolic depolarization, prompting the ensemble of surface membrane ion channels to generate the next action potential (AP). Objective To determine if mitochondrial Ca2+ (Ca2+m), cytosolic Ca2+ (Ca2+c)-SR-Ca2+ crosstalk occurs in single rabbit SANC, and how this may relate to SANC normal automaticity. Results Inhibition of mitochondrial Ca2+ influx into (Ru360) or Ca2+ efflux from (CGP-37157) decreased [Ca2+]m to 80±8% control or increased [Ca2+]m to 119±7% control, respectively. Concurrent with inhibition of mitochondrial Ca2+ influx or efflux, the SR Ca2+ load, and LCR size, duration, amplitude and period (imaged via confocal linescan) significantly increased or decreased, respectively. Changes in total ensemble LCR Ca2+ signal were highly correlated with the change in the SR Ca2+ load (r2?=?0.97). Changes in the spontaneous AP cycle length (Ru360, 111±1% control; CGP-37157, 89±2% control) in response to changes in [Ca2+]m were predicted by concurrent changes in LCR period (r2?=?0.84). Conclusion A change in SANC Ca2+m flux translates into a change in the AP firing rate by effecting changes in Ca2+c and SR Ca2+ loading, which affects the characteristics of spontaneous SR Ca2+ release. PMID:22666369

  17. [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. PMID:21435931

  18. 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

  19. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 2 2012-10-01 2012-10-01 false Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage. 410.49 Section 410.49 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM SUPPLEMENTARY MEDICAL INSURANCE (SMI) BENEFITS Medical and...

  20. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 2 2013-10-01 2013-10-01 false Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage. 410.49 Section 410.49 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM SUPPLEMENTARY MEDICAL INSURANCE (SMI) BENEFITS Medical and...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  2. Heart pacemaker

    MedlinePLUS

    ... 1 ounce. Most pacemakers have 2 parts: The generator contains the battery and the information to control ... are wires that connect the heart to the generator and carry the electrical messages to the heart. ...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MEDICAL INSURANCE (SMI) BENEFITS Medical and Other Health Services § 410.49 Cardiac rehabilitation program... following: (i) A description of the individual's diagnosis. (ii) The type, amount, frequency, and duration... that is providing intensive cardiac rehabilitation utilizing an approved ICR program. Medical...

  4. 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)

  5. Cyanide inhibits the Na+/Ca2+ exchanger in isolated cardiac pacemaker cells of the cane toad.

    PubMed

    Ju, Yue-kun; Allen, David G

    2005-02-01

    The effects of the metabolic inhibition on the activity of the Na+/Ca2+ exchanger (NCX) were studied in single isolated pacemaker cells from the cane toad. Ca2+ influx on NCX (reverse mode) was estimated by measuring the increase in intracellular calcium concentration ([Ca2+]i) in response to extracellular Na+-free solution. After application of 2 mM sodium cyanide for 3-5 min, the peak [Ca2+]i in Na+-free solution was significantly decreased from 377+/-42 nM to 260+/-46 nM, suggesting inhibition of NCX. To study Ca2+ efflux on NCX (forward mode), we recorded the tail currents on repolarization which were abolished by Ni2+ and by Na+-free solution. Cyanide decreased the amplitude of tail currents by 36+/-3%. To investigate the intrinsic properties of NCX during the metabolic inhibition, we used rapid application of caffeine to trigger sarcoplasmic reticulum Ca2+ release, which then stimulates NCX current (I(NCX) ). Both the caffeine-induced peak [Ca2+]i and the peak I(NCX) were reduced by cyanide exposure. When I(NCX) was plotted against [Ca2+], the slope of the decay phase was decreased in the presence of CN- to 44+/-8% of control, indicating that for a given [Ca2+]i there was less I(NCX) produced. These results show that cyanide (CN-) inhibits NCX activity at least partly through changes in the intrinsic properties of NCX. The inhibition of NCX probably contributes to the slower firing rate of pacemaker cells in CN-. PMID:15688245

  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

    ... (iii) 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 programs,...

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... (iii) 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 programs,...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... (iii) 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 programs,...

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... (iii) 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 programs,...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... (iii) 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 programs,...

  11. Cardiac fiber unfolding by semidefinite programming.

    PubMed

    Li, Hongying; Robini, Marc C; Yang, Feng; Magnin, Isabelle; Zhu, Yuemin

    2015-02-01

    Diffusion-tensor imaging allows noninvasive assessment of the myocardial fiber architecture, which is fundamental in understanding the mechanics of the heart. In this context, tractography techniques are often used for representing and visualizing cardiac fibers, but their output is only qualitative. We introduce here a new framework toward a more quantitative description of the cardiac fiber architecture from tractography results. The proposed approach consists in taking three-dimensional (3-D) fiber tracts as inputs, and then unfolding these fibers in the Euclidean plane under local isometry constraints using semidefinite programming. The solution of the unfolding problem takes the form of a Gram matrix which defines the two-dimensional (2-D) embedding of the fibers and whose spectrum provides quantitative information on their organization. Experiments on synthetic and real data show that unfolding makes it easier to observe and to study the cardiac fiber architecture. Our conclusion is that 2-D embedding of cardiac fibers is a promising approach to supplement 3-D rendering for understanding the functioning of the heart. PMID:25291787

  12. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... prescribed exercise, cardiac risk factor modification, psychosocial assessment, and outcomes assessment... the program and at the end of the program. (ii) Objective clinical measures of exercise performance... osteopathy as defined in section 1861(r)(1) of the Act. Physician-prescribed exercise means aerobic...

  13. 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...

  14. 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...

  15. 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...

  16. 21 CFR 870.1750 - External programmable pacemaker pulse generator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false External programmable pacemaker pulse generator... 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...

  17. 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...

  18. Gene therapy: Biological pacemaker created by gene transfer

    NASA Astrophysics Data System (ADS)

    Miake, Junichiro; Marbán, Eduardo; Nuss, H. Bradley

    2002-09-01

    The pacemaker cells of the heart initiate the heartbeat, sustain the circulation, and dictate the rate and rhythm of cardiac contraction. Circulatory collapse ensues when these specialized cells are damaged by disease, a situation that currently necessitates the implantation of an electronic pacemaker. Here we report the use of viral gene transfer to convert quiescent heart-muscle cells into pacemaker cells, and the successful generation of spontaneous, rhythmic electrical activity in the ventricle in vivo. Our results indicate that genetically engineered pacemakers could be developed as a possible alternative to implantable electronic devices.

  19. Cardiac rehabilitation programs and the problem of patient dropout.

    PubMed

    Mullinax, C H

    1995-01-01

    As one of the leading causes of death in the United States, coronary atherosclerotic heart disease (CAHD) has been shown to have a reduced incidence if the principles of primary prevention are instituted to reduce cardiac risk factors. In people who already suffer from CAHD, employing secondary prevention such as controlling hypertension, reducing serum lipid levels, eliminating nicotine intake, reducing stress, losing weight, and increasing exercise habits can decrease recurrence of problems related to CAHD. Cardiac rehabilitation programs are a way to help CAHD patients restore optimal medical, physiological, psychological, social, and vocational performance following an acute cardiac event. A major problem in cardiac rehabilitation programs is patient dropout. For any cardiac rehabilitation program to be a success, the CAHD patient must become invested in the maintenance of health and, therefore, committed to participation in the program. The author reviews the current literature, including discussions of the history of cardiac rehabilitation, current trends in cardiac rehabilitation programs, factors that influence patients' investment in these programs, and ways in which the cardiac rehabilitation nurse might intervene to make an impact on patients' participation. PMID:7709050

  20. Pacemaker insertion

    PubMed Central

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

    2015-01-01

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

  1. Heart pacemaker - discharge

    MedlinePLUS

    ... pacemaker is placed under your skin. These include: Battery powered cordless tools (such as screwdrivers and drills) ... will take about 15 to 30 minutes. The batteries in your pacemaker should last 6 to 15 ...

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

    PubMed

    Rapsang, Amy G; Bhattacharyya, Prithwis

    2014-01-01

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

  3. 76 FR 47085 - Effective Date of Requirement for Premarket Approval for a Pacemaker Programmer

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-04

    ...panel's recommendation. C. Risks to Health 1. Cardiac arrhythmias or electrical shock: Excessive electrical leakage current...electrophysiology of the heart, leading to the onset of cardiac arrhythmias. 2. Improper pacemaker operation: Inadequate design...

  4. [Pacemakers 16 years later].

    PubMed

    Dodinot, B

    1976-01-01

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

  5. Overlapping cardiac programs in heart development and regeneration.

    PubMed

    Zhen, Yi-Song; Wu, Qing; Xiao, Cheng-Lu; Chang, Nan-Nan; Wang, Xu; Lei, Lei; Zhu, Xiaojun; Xiong, Jing-Wei

    2012-09-20

    Gaining cellular and molecular insights into heart development and regeneration will likely provide new therapeutic targets and opportunities for cardiac regenerative medicine, one of the most urgent clinical needs for heart failure. Here we present a review on zebrafish heart development and regeneration, with a particular focus on early cardiac progenitor development and their contribution to building embryonic heart, as well as cellular and molecular programs in adult zebrafish heart regeneration. We attempt to emphasize that the signaling pathways shaping cardiac progenitors in heart development may also be redeployed during the progress of adult heart regeneration. A brief perspective highlights several important and promising research areas in this exciting field. PMID:23021544

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

    PubMed Central

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

    2006-01-01

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

  7. Design and Testing of a Percutaneously Implantable Fetal Pacemaker GERALD E. LOEB,1

    E-print Network

    Meng, Ellis

    , cylindrical shape that permits percutaneous implanta- tion into a fetus to treat complete heart block of the pacemaker and a short, flexible lead entirely within the chest of the fetus to avoid dislodgement from fetal in the pulsing rate. Keywords--Cardiac pacemaker, Fetus, Congenital heart block, Complete heart block, Hydrops

  8. Pacemaker Control of Heart Rate Variability: A Cyber Physical System Perspective

    E-print Network

    Bruck, Jehoshua (Shuki)

    50 Pacemaker Control of Heart Rate Variability: A Cyber Physical System Perspective PAUL BOGDAN Mellon University Cardiac diseases, like those related to abnormal heart rate activity, have an enormous pacemakers ignore the fractal nature of heart rate activity. The purpose of this article is to present

  9. 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

  10. Engineered Biological Pacemakers

    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.

  11. Delayed right-ventricular perforation by pacemaker lead; a rare complication in a 12-year-old girl.

    PubMed

    Aykan, Hayrettin Hakan; Ak?n, Alper; Ertu?rul, ?lker; Karagöz, Tevfik

    2015-03-01

    Developments in the diagnosis and treatment of congenital heart diseases have led to an increase in the need for intracardiac pacemaker and implantable cardioverter defibrillator (ICD) implantation. Various complications related to these interventions can be seen in the short term (pneumothorax, pericardial effusion, cardiac perforation, etc…) and in the long term (infection, subclavian vein thrombosis, sensing and pacing problems, battery erosion and cardiac perforation). In this report, we present a rare case of cardiac perforation occurring 2 years after pacemaker implantation. PMID:25782125

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

    PubMed

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

    2013-09-01

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

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

    PubMed

    Ochasi, Aloysius; Clark, Peter

    2015-12-01

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

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

    PubMed Central

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

    2014-01-01

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

  15. Stem cell-based biological pacemakers from proof of principle to therapy: a review.

    PubMed

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

    2014-07-01

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

  16. 21 CFR 870.3670 - Pacemaker charger.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker...

  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. PMID:9498129

  18. Pacemakers and Implantable Defibrillators - Multiple Languages: MedlinePlus

    MedlinePLUS

    ... Institute Pacemaker (Arabic) ??????? Bilingual PDF Health Information Translations Chinese - Simplified (????) Pacemaker ????? - ???? (Chinese - Simplified) Bilingual PDF Health Information Translations Chinese - Traditional (????) Pacemaker ????? - ???? (Chinese - Traditional) ...

  19. A randomized controlled clinical trial of pacemaker follow-up in clinic and by telemedical interpretation of the pacemakers' magnet mode.

    PubMed

    Hayn, Dieter; Kollmann, Alexander; Perl, Sabine; Kos, Cornelia; Rotman, Brigitte; Lercher, Peter; Tscheliessnigg, Karl-Heinz; Schreier, Günter

    2013-12-01

    We assessed a two-stage follow-up procedure for cardiac pacemakers, where in-clinic follow-ups were partly replaced by telemedical follow-ups. This was compared with the standard follow-up regime (in-clinic follow-up only). The new procedure required an electronic patient record, a telemedical follow-up unit for recording ECGs while the pacemaker was temporarily set to magnet mode, an ECG processing unit, and a reviewing and reporting unit. A total of 177 (86 female) patients were randomized to the control group and 182 (98 female) patients to the telemedicine group. In the telemedicine group, 234 telemedical follow-ups were performed. Out of these, 68 required an additional in-clinic follow-up, while 166 were sufficient for assessing the pacemakers' working status. During the study, there were 19 deaths in the telemedicine group and 20 in the control group. There was no significant difference between the two groups(P?=?0.40). The probability that an individual patient's pacemaker would not to be replaced over time was analysed in a similar way to the Kaplan-Meier survival function. Fewer pacemakers were replaced in the telemedicine group (14) than in the control group (18), but the difference was not significant (P?=?0.26). We conclude that alternating telemedical and in-clinic follow-ups brings no additional risks for patients. The follow-up procedure is feasible and interpretation of the pacemakers' magnet effect provides an easy-to-use, manufacturer-independent method of assessing the pacemakers' working status. This should reduce the patient load on pacemaker centres and decrease the overall costs of pacemaker therapy. PMID:24197403

  20. Pacemaker limitation of tachycardia in hypovolemic shock.

    PubMed

    Sparacino, Nicholas; Geninatti, Marilyn; Moore, Gregory

    2011-11-01

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

  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. PMID:23757477

  2. Developing a Culturally Based Cardiac Rehabilitation Program: The HELA Study

    PubMed Central

    Look, Mele A; Kaholokula, Joseph Keawe‘aimoku; Carvahlo, Amy; Seto, Todd B.; de Silva, Mapuana

    2012-01-01

    Background Heart disease disproportionately affects Native Hawaiians and other Pacific people. In response, researchers proposed and communities endorsed, developing a cardiac rehabilitation (CR) program based on the hula, a Native Hawaiian dance form. The utilization of cultural practices in health interventions can improve outcomes and increase enrollment and retention, but requires sensitivity and understanding. Objective This paper provides the conceptual framework and methods used for integration of multiple communities’ perspectives to inform the design of a hula-based CR intervention. Methods Specific strategies and processes were established to ensure the equity of scientific—clinical and patient—cultural knowledge and perspectives. Multiple methods were used and a flow diagram defined steps for the intervention development. Results Patient and cultural consultations provided information about the multidimensional benefits of hula and its use in a CR intervention. Clinical and scientific consultations provided specific guidelines for exercise prescription and patient monitoring. Integrating findings from all consultations identified important direction and requirements. Conclusions Community-based participatory research (CBPR) principles guided a complex collaboration of multiple communities; although time consuming, inclusive consultations provided valuable information and relationships. PMID:22643794

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

    PubMed

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

    1987-09-01

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

  4. 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.

  5. [Hyperkalemia-induced failure of pacemaker capture and sensing: a case report].

    PubMed

    Wang, Y P; Chen, B X; Su, K J; Sun, L J; Zhang, Y; Guo, L J; Gao, W

    2014-12-18

    Hyperkalemia may induce serious cardiac arrhythmia, with possible life-threatening effects. It may cause cardiac pacemaker (PMK) malfunctioning due to a reduction of the electronegativity of the resting myocardial potential. We report the case of a 71-year-old woman who had a previous history of chronic heart failure, chronic renal failure and DDI pacemaker. She was admitted for disturbance of consciousness. During hospitalization, she was observed for extreme hypotension, acute hyperkalemia, ventricular escape rhythm, associated with failure of pacemaker capture and sensing. She was treated with calcium chloride injection, followed by insulin/glucose and sodium bicarbonate infusions; the electrocardiogram recordings showed an correction of the PMK malfunctioning and serial improvement of the intraventricular conduction. This case supports that hyperkalemia should be closely monitored in the chronic heart failure patients combined with chronic renal failure. PMID:25512296

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

    PubMed

    Sarela, Antti; Whittaker, Frank; Korhonen, Ilkka

    2009-01-01

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

  7. 21 CFR 870.3700 - Pacemaker programmers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3700 Pacemaker programmers. (a) Identification. A pacemaker programmer is a device used...

  8. Design and testing of a percutaneously implantable fetal pacemaker.

    PubMed

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

    2013-01-01

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

  9. Design and Testing of a Percutaneously Implantable Fetal Pacemaker

    PubMed Central

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

    2012-01-01

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

  10. Pediatric pacemakers and ICDs: how to optimize perioperative care.

    PubMed

    Navaratnam, Manchula; Dubin, Anne

    2011-05-01

    An increasing number of pediatric patients with permanent pacemakers and implantable cardioverter defibrillators (ICDs) require cardiac and noncardiac surgery. It is critical that the anesthesiologist caring for these patients understands the management of the device and the underlying heart disease. Children with these devices are more vulnerable to lead failure and inappropriate shocks compared with the adult population. Preoperative assessment and appropriate reprogramming of the device, in addition to minimizing sources of electromagnetic interference, are keystones in the perioperative care of these patients. Prior consultation with qualified programmers is recommended to enable timely optimization of the device. Magnets may be used in emergency situations but it is important to appreciate the limitations of magnet use on different models of pacemakers and ICDs. Safe and successful perioperative care is dependent upon a well-organized and coordinated multidisciplinary team approach. PMID:21481077

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

    PubMed

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

    2004-01-01

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

  12. Clinical experience with nuclear pacemakers.

    PubMed

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

    1975-12-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

    Mond, Harry G; Freitag, Gary

    2014-12-01

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

  15. Is lower base rate detrimental to transcatheter aortic valve implantation patients requiring pacemakers?

    PubMed

    Shurrab, Mohammed; Singarajah, Theepana; Wijeysundera, Harindra C; Haj-Yahia, Saleem; Newman, David; Crystal, Eugene; Lashevsky, Ilan

    2015-11-01

    Sudden cardiac death related to polymorphic ventricular tachycardia/ventricular fibrillation has been well reported post atrioventricular junction ablation. The practice of faster pacing rate immediately after atrioventricular junction ablation is well recognized to decrease the risk of sudden cardiac death. We propose that this practice (faster pacing rate) be implemented in patients who need permanent pacemakers secondary to transcatheter aortic valve implantation (or even surgical aortic valve interventions). PMID:26414946

  16. 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.

  17. 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. PMID:5470044

  18. UNIVERSITY OF ALBERTA Cardiology Residency Training Program

    E-print Network

    MacMillan, Andrew

    . Electrophysiology (ECGs, ambulatory monitoring, pacemakers, invasive EP studies & ablation) g. Invasive cardiology examination, hemodynamics, angiography and interventional cardiology, advanced cardiac imaging, ECG

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

    PubMed

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

    2014-04-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-09-16

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

  2. 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.

  3. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric... A pacemaker polymeric mesh bag is an implanted device used to hold a pacemaker pulse...The bag is designed to create a stable implant environment for the pulse...

  4. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric... A pacemaker polymeric mesh bag is an implanted device used to hold a pacemaker pulse...The bag is designed to create a stable implant environment for the pulse...

  5. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870...Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device...

  6. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Pacemaker lead adaptor. 870.3620 Section 870.3620...Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device used to adapt a...

  7. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Pacemaker lead adaptor. 870.3620 Section 870.3620...Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device used to adapt a...

  8. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Pacemaker lead adaptor. 870.3620 Section 870.3620...Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device used to adapt a...

  9. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Pacemaker lead adaptor. 870.3620 Section 870.3620...Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device used to adapt a...

  10. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Pacemaker lead adaptor. 870.3620 Section 870.3620...Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device used to adapt a...

  11. 21 CFR 870.3690 - Pacemaker test magnet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Pacemaker test magnet. 870.3690 Section 870.3690 Food...Prosthetic Devices § 870.3690 Pacemaker test magnet. (a) Identification. A pacemaker test magnet is a device used to test an...

  12. 21 CFR 870.3690 - Pacemaker test magnet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2014-04-01 false Pacemaker test magnet. 870.3690 Section 870.3690 Food...Prosthetic Devices § 870.3690 Pacemaker test magnet. (a) Identification. A pacemaker test magnet is a device used to test an...

  13. 21 CFR 870.3690 - Pacemaker test magnet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 false Pacemaker test magnet. 870.3690 Section 870.3690 Food...Prosthetic Devices § 870.3690 Pacemaker test magnet. (a) Identification. A pacemaker test magnet is a device used to test an...

  14. 21 CFR 870.3690 - Pacemaker test magnet.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Pacemaker test magnet. 870.3690 Section 870.3690 Food...Prosthetic Devices § 870.3690 Pacemaker test magnet. (a) Identification. A pacemaker test magnet is a device used to test an...

  15. 21 CFR 870.3690 - Pacemaker test magnet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 false Pacemaker test magnet. 870.3690 Section 870.3690 Food...Prosthetic Devices § 870.3690 Pacemaker test magnet. (a) Identification. A pacemaker test magnet is a device used to test an...

  16. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870.3650 Food... § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold a...

  17. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870.3650 Food... § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold a...

  18. 21 CFR 870.3600 - External pacemaker pulse generator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false External pacemaker pulse generator. 870.3600 Section 870.3600...870.3600 External pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has a...

  19. 21 CFR 870.3630 - Pacemaker generator function analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 false Pacemaker generator function analyzer. 870.3630 ...Prosthetic Devices § 870.3630 Pacemaker generator function analyzer. (a) Identification. A pacemaker generator function analyzer is a device...

  20. 21 CFR 870.3610 - Implantable pacemaker pulse generator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...false Implantable pacemaker pulse generator. 870.3610 Section 870.3610...3610 Implantable pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a...

  1. 21 CFR 870.3640 - Indirect pacemaker generator function analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Indirect pacemaker generator function analyzer. 870.3640...870.3640 Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker generator function analyzer is an...

  2. 21 CFR 870.3610 - Implantable pacemaker pulse generator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...false Implantable pacemaker pulse generator. 870.3610 Section 870.3610...3610 Implantable pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a...

  3. 21 CFR 870.3630 - Pacemaker generator function analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Pacemaker generator function analyzer. 870.3630 ...Prosthetic Devices § 870.3630 Pacemaker generator function analyzer. (a) Identification. A pacemaker generator function analyzer is a device...

  4. 21 CFR 870.3600 - External pacemaker pulse generator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false External pacemaker pulse generator. 870.3600 Section 870.3600...870.3600 External pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has a...

  5. 21 CFR 870.1750 - External programmable pacemaker pulse generator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...External programmable pacemaker pulse generator. 870.1750 Section 870.1750...External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker pulse generators is a device that can be...

  6. 21 CFR 870.3600 - External pacemaker pulse generator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false External pacemaker pulse generator. 870.3600 Section 870.3600...870.3600 External pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has a...

  7. 21 CFR 870.1750 - External programmable pacemaker pulse generator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...External programmable pacemaker pulse generator. 870.1750 Section 870.1750...External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker pulse generators is a device that can be...

  8. 21 CFR 870.3600 - External pacemaker pulse generator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false External pacemaker pulse generator. 870.3600 Section 870.3600...870.3600 External pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has a...

  9. 21 CFR 870.3630 - Pacemaker generator function analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2014-04-01 false Pacemaker generator function analyzer. 870.3630 ...Prosthetic Devices § 870.3630 Pacemaker generator function analyzer. (a) Identification. A pacemaker generator function analyzer is a device...

  10. 21 CFR 870.3610 - Implantable pacemaker pulse generator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...false Implantable pacemaker pulse generator. 870.3610 Section 870.3610...3610 Implantable pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a...

  11. 21 CFR 870.3640 - Indirect pacemaker generator function analyzer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Indirect pacemaker generator function analyzer. 870.3640...870.3640 Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker generator function analyzer is an...

  12. 21 CFR 870.1750 - External programmable pacemaker pulse generator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...External programmable pacemaker pulse generator. 870.1750 Section 870.1750...External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker pulse generators is a device that can be...

  13. 21 CFR 870.3630 - Pacemaker generator function analyzer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Pacemaker generator function analyzer. 870.3630 ...Prosthetic Devices § 870.3630 Pacemaker generator function analyzer. (a) Identification. A pacemaker generator function analyzer is a device...

  14. 21 CFR 870.3610 - Implantable pacemaker pulse generator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...false Implantable pacemaker pulse generator. 870.3610 Section 870.3610...3610 Implantable pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a...

  15. 21 CFR 870.3640 - Indirect pacemaker generator function analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Indirect pacemaker generator function analyzer. 870.3640...870.3640 Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker generator function analyzer is an...

  16. 21 CFR 870.3610 - Implantable pacemaker pulse generator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...false Implantable pacemaker pulse generator. 870.3610 Section 870.3610...3610 Implantable pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a...

  17. 21 CFR 870.3630 - Pacemaker generator function analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 false Pacemaker generator function analyzer. 870.3630 ...Prosthetic Devices § 870.3630 Pacemaker generator function analyzer. (a) Identification. A pacemaker generator function analyzer is a device...

  18. 21 CFR 870.3640 - Indirect pacemaker generator function analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Indirect pacemaker generator function analyzer. 870.3640...870.3640 Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker generator function analyzer is an...

  19. 21 CFR 870.1750 - External programmable pacemaker pulse generator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...External programmable pacemaker pulse generator. 870.1750 Section 870.1750...External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker pulse generators is a device that can be...

  20. 21 CFR 870.1750 - External programmable pacemaker pulse generator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...External programmable pacemaker pulse generator. 870.1750 Section 870.1750...External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker pulse generators is a device that can be...

  1. 21 CFR 870.3640 - Indirect pacemaker generator function analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Indirect pacemaker generator function analyzer. 870.3640...870.3640 Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker generator function analyzer is an...

  2. 21 CFR 870.3600 - External pacemaker pulse generator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false External pacemaker pulse generator. 870.3600 Section 870.3600...870.3600 External pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has a...

  3. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...false Pacemaker electrode function tester. 870.3720 Section...3720 Pacemaker electrode function tester. (a) Identification. A pacemaker electrode function tester is a device which...threshold and intracardiac R-wave potential. (b)...

  4. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...false Pacemaker electrode function tester. 870.3720 Section...3720 Pacemaker electrode function tester. (a) Identification. A pacemaker electrode function tester is a device which...threshold and intracardiac R-wave potential. (b)...

  5. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...false Pacemaker electrode function tester. 870.3720 Section...3720 Pacemaker electrode function tester. (a) Identification. A pacemaker electrode function tester is a device which...threshold and intracardiac R-wave potential. (b)...

  6. 21 CFR 870.3700 - Pacemaker programmers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3700 Pacemaker programmers. (a) Identification. A...

  7. Pacemakers (Beyond the Basics)

    MedlinePLUS

    ... may require specific reprogramming before the procedure and programming back to its baseline condition after the procedure. ... not include Internet access to the Licensed Materials. c. INSTITUTIONAL SUBSCRIPTION: An Institutional Subscription permits only individuals ...

  8. 21 CFR 870.3730 - Pacemaker service tools.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3730 Pacemaker service tools. (a) Identification. Pacemaker service tools are devices...

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3710 Pacemaker repair or replacement material. (a) Identification. A pacemaker repair...

  10. Pacemaker safety and long-distance running

    PubMed Central

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

    2004-01-01

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

  11. Cardiac sarcoidosis: a comprehensive review

    PubMed Central

    Sekhri, Vishal; Sanal, Shireen; DeLorenzo, Lawrence J.; Aronow, Wilbert S.; Maguire, George P.

    2011-01-01

    Sarcoidosis is a multisystem granulomatous disease of unknown etiology characterized by noncaseating granulomas in involved organs. Organs involved with sarcoidosis include lymph nodes, skin, lung, central nervous system, and eye. Only 40-50% of patients with cardiac sarcoidosis diagnosed at autopsy have the diagnosis made during their lifetime. Cardiac sarcoidosis can manifest itself as complete heart block, ventricular arrhythmias, congestive heart failure, pericardial effusion, pulmonary hypertension, and ventricular aneurysms. Diagnostic tests such as the electrocardiogram, two-dimensional echocardiography, cardiac magnetic resonance imaging, positron emission tomography scan, radionuclide scan, and endomyocardial biopsy can be helpful in the early detection of cardiac sarcoidosis. Considering the increased risk of sudden death, cardiac sarcoidosis is an indication for early treatment with corticosteroids or other immunosuppressive agents. Other treatments include placement of a pacemaker or implantable defibrillator to prevent sudden death. In refractory cases, cardiac transplantation should be considered. PMID:22291785

  12. 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... 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. 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...

  14. 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...

  15. 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...

  16. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pacemaker lead adaptor. 870.3620 Section 870.3620...) 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...

  17. 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...

  18. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pacemaker lead adaptor. 870.3620 Section 870.3620...) 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...

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

    SciTech Connect

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

    2014-06-01

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

  20. Damaging effect of therapeutic radiation on programmable pacemakers

    SciTech Connect

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

    1982-03-01

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

  1. Pacemakers charging using body energy.

    PubMed

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

    2010-01-01

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

  2. Pacemakers charging using body energy

    PubMed Central

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

    2010-01-01

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

  3. Acute Coronary Syndrome and Cardiac Arrest: Using Simulation to Assess Resident Performance and Program Outcomes

    PubMed Central

    Opar, Susan P.; Short, Matthew W.; Jorgensen, Jennifer E.; Blankenship, Robert B.; Roth, Bernard J.

    2010-01-01

    Background Simulation training has emerged as an effective method of educating residents in cardiac emergencies. Few studies have used emergency simulation scenarios as an outcome measure to identify training deficiencies within residency programs. Purpose The purpose of this study was to evaluate postgraduate year-1 (PGY-1) residents on their ability to manage an acute coronary syndrome and cardiac arrest scenario before and after internship in order to provide outcome data to improve program performance. Methods A total of 58 PGY-1 residents from 10 medical specialties were evaluated using a human patient simulator before and after internship. They were given 12 minutes to manage a patient with acute coronary syndrome and ventricular fibrillation due to hyperkalemia. An objective checklist following basic and advanced cardiac life support guidelines was used to assess performance. Results A total of 58 interns (age, 25 to 44 years [mean, 29.1]; 38 [65.6%] men; 41 [70.7%] allopathic medical school graduates) participated in both the incoming and outgoing examination. Overall chest pain scores increased from a mean of 60.0% to 76.1% (P < .01). Medical knowledge performance improved from 51.1% to 76.1% (P < .01). Systems-based practice performance improved from 40.9% to 71.0% (P < .01). However, patient care performance declined from 93.4% to 80.2% (P < .01). Conclusions A simulated acute coronary syndrome and cardiac arrest scenario can evaluate incoming PGY-1 competency performance and test for interval improvement. This assessment tool can measure resident competency performance and evaluate program effectiveness. PMID:21976090

  4. 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 ...

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

    PubMed

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

    2016-01-01

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

  6. How Will a Pacemaker Affect My Lifestyle?

    MedlinePLUS

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

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed Central

    Jalife, J

    1984-01-01

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

  10. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3720 Pacemaker electrode function tester...electrode function tester is a device which is connected to an implanted pacemaker lead that supplies an accurately...

  11. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3720 Pacemaker electrode function tester...electrode function tester is a device which is connected to an implanted pacemaker lead that supplies an accurately...

  12. Cardiac resynchronization therapy: Dire need for targeted left ventricular lead placement and optimal device programming

    PubMed Central

    Pastromas, Sokratis; Manolis, Antonis S

    2014-01-01

    Cardiac resynchronization therapy (CRT) effected via biventricular pacing has been established as prime therapy for heart failure patients of New York Heart Association functional class II, III and ambulatory IV, reduced left ventricular (LV) function, and a widened QRS complex. CRT has been shown to improve symptoms, LV function, hospitalization rates, and survival. In order to maximize the benefit from CRT and reduce the number of non-responders, consideration should be given to target the optimal site for LV lead implantation away from myocardial scar and close to the latest LV site activation; and also to appropriately program the device paying particular attention to optimal atrioventricular and interventricular intervals. We herein review current data related to both optimal LV lead placement and device programming and their effects on CRT clinical outcomes. PMID:25548617

  13. 21 CFR 870.3610 - Implantable pacemaker pulse generator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Implantable pacemaker pulse generator. 870.3610 Section 870.3610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

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

    PubMed

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

    2015-12-23

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

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

    PubMed

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

    2015-12-01

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

  16. Cardiac rehabilitation outcomes following a 6-week program of PCI and CABG Patients.

    PubMed

    Jelinek, Herbert F; Huang, Zhaoqi Q; Khandoker, Ahsan H; Chang, Dennis; Kiat, Hosen

    2013-01-01

    Coronary artery events requiring intervention are associated with depressed cardiac autonomic function. Whether a 6-week cardiac rehabilitation (CR) differs in effectiveness in improving exercise capacity (6MWT), cardiorespiratory function (peakVO2), and autonomic function (HRV) following either cardiac bypass surgery (CABG) or percutaneous coronary revascularization (PCI) is unknown. The current study therefore compared the change in 6MWT and peak VO2 to HRV variables following a 6-week CR program and with patients having either PCI or CABG. Thirty-eight patients, (PCI, n = 22 and CABG, n = 16) participated in the CR program and results for pre and post 6 min walk test (6MWT), peakVO2, and heart rate variability (HRV) were obtained. Our study has shown that a 6 weeks program following either PCI or CABG improves function. However, the effect on post-CABG differs to that of post-PCI patients. The change in distance walked (6MWT, metres) was higher in the CABG (?6MWT: 61, p < 0.001) compared to the PCI group (?6MWT: 41, p < 0.001). Maximum exercise capacity (peak VO2, ml/kg.min) also changed significantly with a greater change in the CABG group (?PCI: 0.7, p < 0.001; ?CABG: 1.0, p < 0.001) but did not reach normal population values. Although an improvement in HRV parameters was noted for the PCI group, a statistically significant improvement in HRV was observed only in the CABG group for the following; SDNN (ms) (baseline vs. post-rehabilitation (median ± IQR): 31.2 ± 25.6 vs. 51.8 ± 23.1, p < 0.01), RMSSD (19.32 ± 19.9 vs. 42.1 ± 34.2, p < 0.01); LF (ms(2)) (191 ± 216 vs. 631 ± 693, p < 0.01) and HF (107 ± 201 vs. 449 ± 795.0, p < 0.05). A significant interaction in the PCI group but not in the CABG group was observed using correlation analysis between the 6MWT and peak VO2 with HRV parameters indicating that being healthier that is, a better 6MWT and peak VO2 led to better HRV results but no significant effect of CR in the PCI group. When the results were investigated for baseline 6MWT and peak VO2 effect using a covariate analysis, a significant influence of CR on HRV parameters was retained in the CABG group (p = 0.0072). Our study indicates that a 6-weeks CR program benefits both patient groups in terms of exercise capacity, cardiorespiratory function and autonomic nervous system modulation of heart rate, with CABG patients showing the most improvement. HRV can be a useful additional variable to gauge cardiac function following CR. PMID:24198786

  17. EXTERNAL PACEMAKER By Pat Hock, RN

    E-print Network

    Kay, Mark A.

    will be to the pt's intrinsic rhythm. Failure to capture occurs when the output stimulus fails to depolarize the myocardium. Causes include lead disconnect or fracture, low battery, low output setting, or an increase in the pacing threshold because of edema or scarring. Failure to sense occurs when the pacemaker fails to detect

  18. Comparison of cardiac rehabilitation programs combined with relaxation and meditation techniques on reduction of depression and anxiety of cardiovascular patients.

    PubMed

    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

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

    PubMed

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

    2008-07-01

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

  20. Gene therapy in cardiac arrhythmias.

    PubMed

    Praveen, S V; Francis, Johnson; Venugopal, K

    2006-01-01

    Gene therapy has progressed from a dream to a bedside reality in quite a few human diseases. From its first application in adenosine deaminase deficiency, through the years, its application has evolved to vascular angiogenesis and cardiac arrhythmias. Gene based biological pacemakers using viral vectors or mesenchymal cells tested in animal models hold much promise. Induction of pacemaker activity within the left bundle branch can provide stable heart rates. Genetic modification of the AV node mimicking beta blockade can be therapeutic in the management of atrial fibrillation. G protein overexpression to modify the AV node also is experimental. Modification and expression of potassium channel genes altering the delayed rectifier potassium currents may permit better management of congenital long QT syndromes. Arrhythmias in a failing heart are due to abnormal calcium cycling. Potential targets for genetic modulation include the sarcoplasmic reticulum calcium pump, calsequestrin and sodium calcium exchanger. Lastly the ethical concerns need to be addressed. PMID:16943902

  1. Case report: Perioperative pacemaker-mediated tachycardia in the patient with a dual chamber implantable cardioverter-defibrillator.

    PubMed

    Izrailtyan, Igor; Schiller, Robin J; Katz, Robert I; Almasry, Ibrahim O

    2013-02-01

    Patients with cardiac implantable electronic devices are at additional risk for arrhythmias while undergoing surgical procedures. In this case report, we present a patient with a dual chamber implantable cardioverter-defibrillator who developed intraoperative pacemaker-mediated tachycardia causing significant hemodynamic instability. Management of this arrhythmia can be particularly challenging, because standard application of a magnet does not affect the pacing functions of an implantable cardioverter-defibrillator. Awareness by the anesthesiologist and timely coordination with the cardiac electrophysiology team helped to optimize care for this patient. PMID:23266999

  2. Pediatric cardiac emergencies.

    PubMed

    Lee, C; Mason, L J

    2001-06-01

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

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

    PubMed

    Nordbeck, Peter; Ertl, Georg; Ritter, Oliver

    2015-06-21

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

  4. 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

  5. Pacemaker failures characterized by continuous direct current leakage.

    PubMed

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

    1976-06-01

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

  6. A semi-infinite programming approach to preoperative planning of robotic cardiac surgery under geometric uncertainty.

    PubMed

    Azimian, H; Patel, R V; Naish, M D; Kiaii, B

    2013-01-01

    In this paper, a computational framework for patient-specific preoperative planning of Robotics-Assisted Minimally Invasive Cardiac Surgery (RAMICS) is presented. It is expected that preoperative planning of RAMICS will improve the success rate by considering robot kinematics, patient-specific thoracic anatomy, and procedure-specific intraoperative conditions. Given the significant anatomical features localized in the preoperative computed tomography images of a patients thorax, port locations and robot orientations (with respect to the patients body coordinate frame) are determined to optimize qualities such as dexterity, reachability, tool approach angles and maneuverability. To address intraoperative geometric uncertainty, the problem is formulated as a Generalized Semi-Infinite Program (GSIP) with a convex lower-level problem to seek a plan that is less sensitive to geometric uncertainty in the neighborhood of surgical targets. It is demonstrated that with a proper formulation of the problem, the GSIP can be replaced by a tractable constrained nonlinear program that uses a multi-criteria objective function to balance between the nominal task performance and robustness to collisions and joint limit violations. Finally, performance of the proposed formulation is demonstrated by a comparison between the plans generated by the algorithm and those recommended by an experienced surgeon for several case studies. PMID:23033329

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

    PubMed

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

    2015-04-15

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

  8. 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...

  9. 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...PDP) for implantable pacemaker pulse generators. The Agency has summarized its findings...PDP for the implantable pacemaker pulse generator. In accordance with section...

  10. 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

    ...Approval for an Implantable Pacemaker Pulse Generator AGENCY: Food and Drug Administration...preamendments device implantable pacemaker pulse generator. The Agency is also summarizing its...Proposal--Implantable Pacemaker Pulse Generator (21 CFR 870.3610) A....

  11. 76 FR 64223 - Cardiovascular Devices; Reclassification of External Pacemaker Pulse Generator Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-17

    ...Reclassification of External Pacemaker Pulse Generator Devices; Draft Guidance for Industry...Guidance Document: External Pacemaker Pulse Generator; Availability; Proposed Rule and Notice...Reclassification of External Pacemaker Pulse Generator Devices AGENCY: Food and Drug...

  12. 77 FR 39924 - Effective Date of Requirement for Premarket Approval for Cardiovascular Permanent Pacemaker...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-06

    ...Requirement for Premarket Approval for Cardiovascular Permanent Pacemaker Electrode AGENCY...development protocol (PDP) for the cardiovascular permanent pacemaker electrode. The...notice of completion of a PDP for the cardiovascular permanent pacemaker electrode....

  13. 76 FR 48058 - Effective Date of Requirement for Premarket Approval for Cardiovascular Permanent Pacemaker...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-08

    ...Requirement for Premarket Approval for Cardiovascular Permanent Pacemaker Electrode AGENCY...following class III preamendments device: Cardiovascular permanent pacemaker electrode. The...Agency change the classification of the cardiovascular permanent pacemaker electrode...

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

    PubMed

    Bergamin, C; Graf, D

    2015-05-27

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

  15. 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.

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

    PubMed

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

    2008-03-15

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

  17. 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

  18. 21 CFR 870.3710 - Pacemaker repair or replacement material.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3710 Pacemaker repair or replacement material. (a)...

  19. Experimental molecular and stem cell therapies in cardiac electrophysiology.

    PubMed

    Gepstein, Lior

    2008-03-01

    One of the most exciting fields in cardiovascular research today involves the possible use of stem cells, cell and gene therapies, and tissue engineering for the treatment of a variety of cardiovascular disorders. Here, we review on the possible applications of these emerging strategies in the field of cardiac electrophysiology. Initially, the elegant cell and gene therapy approaches proposed for the treatment of bradyarrhythmias are described. These gene therapy approaches are mainly focused on the generation of biological pacemakers either by altering the neurohumoral control of existing pacemaking cells (by overexpressing the beta-adrenergic receptor) or by converting quiescent cardiomyocytes into pacemaking cells by shifting the balance between diastolic repolarization and depolarization currents. An alternative approach explores the possibility of grafting pacemaking cells, which were either derived directly during the differentiation of human embryonic stem cells or engineered from mesenchymal stem cells, into the myocardium as a cell therapy strategy for biological pacemaking. We then describe the possible applications of similar strategies for the treatment of common tachyarrhythmias by overexpression of different ion channels, or their modifiers, either directly in host cardiomyocytes or ex vivo in cells that will be eventually transplanted into the heart. Next, we discuss the electrophysiological implications of cardiac stem cell therapy for heart failure. Finally, we address the obstacles, challenges, and avenues for further research required to make these novel strategies a clinical reality. PMID:18375594

  20. Cardiac fluid dynamics anticipates heart adaptation.

    PubMed

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

    2015-01-21

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

  1. 21 CFR 870.3600 - External pacemaker pulse generator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false External pacemaker pulse generator. 870.3600 Section 870.3600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3600 External pacemaker pulse generator. (a)...

  2. 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...

  3. 21 CFR 870.3600 - External pacemaker pulse generator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false External pacemaker pulse generator. 870.3600 Section 870.3600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3600 External pacemaker pulse generator. (a)...

  4. 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... electrode function tester. (a) Identification. A pacemaker electrode function tester is a device which is... measuring the patient's pacing threshold and intracardiac R-wave potential. (b) Classification. Class...

  5. 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... electrode function tester. (a) Identification. A pacemaker electrode function tester is a device which is... measuring the patient's pacing threshold and intracardiac R-wave potential. (b) Classification. Class...

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

    PubMed Central

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

    2015-01-01

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

  7. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870.3650 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold...

  8. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870.3650 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold...

  9. 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

  10. Asynchronous response of coupled pacemaker neurons

    E-print Network

    Ramana Dodla; Charles J. Wilson

    2009-02-03

    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.

  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. PMID:16235032

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

    PubMed Central

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

    2012-01-01

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

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

    PubMed

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

    2009-03-01

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

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

    PubMed Central

    Mehani, Sherin H.M.

    2012-01-01

    Chronic heart failure (CHF) is a complex syndrome characterized by progressive decline in left ventricular function, low exercise tolerance and raised mortality and morbidity. Left ventricular diastolic dysfunction plays a major role in CHF and progression of most cardiac diseases. The current recommended goals can theoretically be accomplished via exercise and pharmacological therapy so the aim of the present study was to evaluate the impact of cardiac rehabilitation program on diastolic dysfunction and health related quality of life and to determine the correlation between changes in left ventricular diastolic dysfunction and domains of health-related quality of life (HRQoL). Forty patients with chronic heart failure were diagnosed as having dilated cardiomyopathy (DCM) with systolic and diastolic dysfunction. The patients were equally and randomly divided into training and control groups. Only 30 of them completed the study duration. The training group participated in rehabilitation program in the form of circuit-interval aerobic training adjusted according to 55–80% of heart rate reserve for a period of 7 months. Circuit training improved both diastolic and systolic dysfunction in the training group. On the other hand, only a significant correlation was found between improvement in diastolic dysfunction and health related quality of life measured by Kansas City Cardiomyopathy Questionnaire. It was concluded that improvement in diastolic dysfunction as a result of rehabilitation program is one of the important underlying mechanisms responsible for improvement in health-related quality of life in DCM patients. PMID:25685417

  15. 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,…

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

    PubMed Central

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

    2010-01-01

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

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

    PubMed

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

    1975-05-01

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

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

    PubMed

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

    1980-01-01

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

  19. Effect of Music Therapy with Emotional-Approach Coping on Pre-Procedural Anxiety in Cardiac Catheterization

    E-print Network

    Ghetti, Claire

    2011-06-27

    of invasive procedures are used for diagnosis and treatment of CHD including bypass surgeries, percutaneous coronary interventions (PCI), diagnostic cardiac catheterizations, and implantation of defibrillators and pacemakers. Cardiac catheterization..., and electrophysiological studies. Common to each procedure is the insertion of a catheter, typically via the femoral or radial artery, that is guided toward the blood vessels of the heart. Cardiac catheterization allows visualization of physical structures, blood...

  20. Cardiac pacing in children and adolescents.

    PubMed

    Furman, S; Young, D

    1977-04-01

    Nineteen patients aged 1 month to 18 years underwent implantation of a cardiac pacemaker and were followed up for up to 9 years (average duration of pacing 54 months). Complete heart block was present in 16 patients and sinus nodal dysfunction in 3. Heart block was presumably of congenital orgin in eight, secendary to cardiac surgery in seven and subsequent to cardiac catheterization in one. Sinus nodal dysfunction was of presumed congenital origin in one and occurred after cardiac surgery in two. Pacing was required because of syncopal attacks in eight patients, three of whom had congestive heart failure or low cardiac output on physiologic studies. It was required in four because of congestive heart failure, in two because of low cardiac output (one with a wide QRS complex), and in five for postoperative rhythm control. With return of sinus rhythm after 2 and 3 months, respectively, pacing was discontinued in two patients. One child was partially corrected disease died within 3 months, one died of wound breakdown and sepsis after 10 months of pacing and one died suddenly 4 years after implantation. All others have returned to normal activity; only one requires cardiac medication. The degree of emotional stability has been striking. Asynchronous and atrial synchronous pacing are of equal therapeutic value. The very small radiofrequency implanted receiver has been useful in younger children. The major problems have been caused by the large size and short longevity of the generators and the child's growth stressing the lead system. Transvenously implanted pacemakers have presented no greater management problems than those placed during thoracotomy. PMID:848440

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

    PubMed

    Heinz, M; Wörl, H H; Alt, E; Theres, H; Blömer, H

    1988-11-01

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

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

    PubMed Central

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

    2014-01-01

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

  3. Pacemaker therapy in children with complete heart block.

    PubMed

    Stanton, R E; Lindesmith, G G; Meyer, B W

    1975-04-01

    Permanent pacemaker therapy in children with complete heart block is necessary occasionally. Ten patients ranging in age from 8 months to 15 years were treated with an implanted P-wave, synchronous epicardial pacemaker. Indications for implantation were persisting postsurgical heart block, congestive failure, syncopal attacks, and arrhythmias. There were two deaths not attributed to pacemaker malfunction. The remaining eight children have been followed up for 38 to 108 months. There have been 27 pulse generator replacements. Twenty-three were for battery exhaustion, three for electromechanical failure, and one was due to arrhythmia. Rhythm disturbances have occurred on eight occasions. There have been no infections. It is concluded that the implanted P-wave synchronous pacemaker is an effective method of therapy when indicated for children with complete heart block. PMID:1130355

  4. Repair of a Complex Congenital Cardiac Defect

    MedlinePLUS Videos and Cool Tools

    ... 00:00:14 ANNOUNCER: Over the next hour, live from Children's Hospital Boston's cardiac OR, see cardiac surgeons repair a complex congenital cardiac defect. Each year the pediatric cardiac surgery program provides surgical care to approximately 1,100 patients, including more than 700 cases of open ...

  5. Cardiac pacing and aviation.

    PubMed

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

    1992-12-01

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

  6. Synchronization in chains of pacemaker cells by phase resetting action potential effects.

    PubMed

    de Bruin, G; Ypey, D L; Van Meerwijk, W P

    1983-01-01

    Interactions between pacemaker cells in a chain were calculated according to a "phase-reset" model. It is based on effects of action potentials in the cells on the cycle lengths of neighbouring cells. These effects were defined for each cell by a latency-phase curve (LPC), giving the latency time (L) until the onset of the next action potential in that cell, as a function of the phase (phi) at which a neighbour cell fired an action potential. Neighbour cells with simultaneous action potentials did not influence each others cycle length. We investigated how stable synchronization depends on the shape of the LPC's of the pacemaker cells and on chain length. Three types of interactive behaviour were distinguished. First, anti-phase synchrony, in which neighbouring cells fired with large phase differences with respect to the synchronized period Ps. Second, asynchrony, in which the periods of the cells did not become equal and constant. Third, in-phase synchrony, in which the phase differences between the neighbouring cells were zero or much smaller than the synchronized period Ps, depending on the differences between the intrinsic periods. Asynchrony and anti-phase synchrony may be seen as cardiophysiological arrhythmias, while in-phase synchrony represents the physiological type of synchrony in the heart. In-phase synchrony appeared to be strongly favoured by LPC's, which have a no-effect (refractory) part at early phases, a lengthened latency (or phase delay) part at intermediate phases and a shortened latency (or phase advance) part at late phases in the cycle. Such LPC-shapes are commonly found in preparations of cardiac pacemaker cells. When the pacemaker cells were identical, the synchronized period Ps during in-phase synchrony was equal to their intrinsic period P*i. For different intrinsic periods, Ps was equal to the intrinsic period of the fastest cell if the LPC's contained a sufficiently long initial no-effect period at early phases and a shortened latency part at late phases. When, on the other hand, such cell chains had a linear gradient in their intrinsic periods, "action potentials" started from the fast end and traveled along the chain. The propagation of an action potential wave slowed down as it reached the slower cells. When the gradient in the intrinsic periods was too steep, only the intrinsically fast end of the chain developed synchrony.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6639981

  7. 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

  8. 76 FR 18472 - Medicare Program; Revisions to the Durable Medical Equipment, Prosthetics, Orthotics, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-04

    ...s)(8) of the Act. Prosthetic devices are defined in...Other examples of prosthetic devices include cardiac pacemakers, cochlear implants, electrical continence...to as ``orthotics and prosthetics.'' Under section...

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

    PubMed

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

    2014-10-01

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

  10. Determining the risks of magnetic resonance imaging at 1.5 tesla for patients with pacemakers and implantable cardioverter defibrillators.

    PubMed

    Cohen, Jennifer D; Costa, Heather S; Russo, Robert J

    2012-12-01

    Conventional pacemaker and implantable cardioverter-defibrillator product labeling currently cautions against exposure to magnetic resonance imaging (MRI). However, there is a growing clinical need for MRI, without an acceptable alternative imaging modality in many patients with cardiac devices. The purpose of this study was to determine the risk of MRI at 1.5 T for patients with cardiac devices by measuring the frequency of device failures and clinically relevant device parameter changes. Data from a single-center retrospective review of 109 patients with pacemakers and implantable cardioverter-defibrillators (the MRI group) who underwent 125 clinically indicated MRI studies were compared to data from a prospective cohort of 50 patients with cardiac devices who did not undergo MRI (the control group). In the MRI group, there were no deaths, device failures requiring generator or lead replacement, induced arrhythmias, losses of capture, or electrical reset episodes. Decreases in battery voltage of ?0.04 V occurred in 4%, pacing threshold increases of ?0.5 V in 3%, and pacing lead impedance changes of ?50 ? in 6%. Although there were statistically significant differences between the MRI and control groups for the mean change in pacing lead impedance (-6.2 ± 23.9 vs 3.0 ± 22.1 ?) and left ventricular pacing threshold (-0.1 ± 0.3 vs 0.1 ± 0.2 V), these differences were not clinically important. In conclusion, MRI in patients with cardiac devices resulted in no device or lead failures. A small number of clinically relevant changes in device parameter measurements were noted. However, these changes were similar to those in a control group of patients who did not undergo MRI. PMID:22921995

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

    PubMed Central

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

    2015-01-01

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

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

    SciTech Connect

    Armbruster, John M.

    2011-06-01

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

  13. 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.

  14. [Dying with/despite a pacemaker].

    PubMed

    Reith, S; Janssens, U

    2014-02-01

    Death of intensive care unit (ICU) patients with cardiovascular implantable electronic devices (CIED) is a common scenario in the ICU. Given the demographic trends and the increasing implantation rate of such devices reinforces the fact that ICU physicians must be aware of the burden and consequences of these systems in the end of life care of dying patients. The possible deactivation of a CIED confronts the responsible physicians with particularly complex clinical, ethical, and legal problems. Most deaths are often preceded by a long illness trajectory and finally by altering the therapeutic goals. Withholding or withdrawing therapy are the results of these processes. General agreement exists that ICD deactivation in dying patients may be ethically permissible. The patient's consent is mandatory. The practices and attitudes associated with pacemaker deactivation differ significantly from those associated with ICD deactivation. It is therefore crucial to be aware of the legal situation in the jurisdiction in which the physician is practicing. The decision to deactivate CIEDs should be part of a well deliberated and transparent process. Ethical and legal guidance should be readily available to counsel and support these difficult decisions. PMID:24384727

  15. 76 FR 53851 - Effective Date of Requirement for Premarket Approval for Cardiovascular Permanent Pacemaker...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-30

    ...Effective Date of Requirement for Premarket Approval for Cardiovascular Permanent Pacemaker Electrode; Correction AGENCY: Food...development protocol for the class III preamendments device: Cardiovascular permanent pacemaker electrode. The document was...

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

    ERIC Educational Resources Information Center

    Wilson, Philip K.; Hall, Linda K.

    1984-01-01

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

  17. Measurement of functional capacity requirements of police officers to aid in development of an occupation-specific cardiac rehabilitation training program.

    PubMed

    Adams, Jenny; Schneider, Jonna; Hubbard, Matthew; McCullough-Shock, Tiffany; Cheng, Dunlei; Simms, Kay; Hartman, Julie; Hinton, Paul; Strauss, Danielle

    2010-01-01

    This study was designed to measure the functional capacity of healthy subjects during strenuous simulated police tasks, with the goal of developing occupation-specific training for cardiac rehabilitation of police officers. A calibrated metabolic instrument and an oxygen consumption data collection mask were used to measure the oxygen consumption and heart rates of 30 Dallas Police Academy officers and cadets as they completed an 8-event obstacle course that simulated chasing, subduing, and handcuffing a suspect. Standard target heart rates (85% of age-predicted maximum heart rate, or 0.85 x [220 - age]) and metabolic equivalents (METs) were calculated; a matched-sample t test based on differences between target and achieved heart rate and MET level was used for statistical analysis. Peak heart rates during the obstacle course simulation were significantly higher than the standard target heart rates (those at which treadmill stress tests in physicians' offices are typically stopped) (t(29) = 12.81, P < 0.001) and significantly higher than the suggested maximum of 150 beats/min during cardiac rehabilitation training (t(29) = 17.84, P < 0.001). Peak MET levels during the obstacle course simulation were also significantly higher than the goal level (8 METs) that patients typically achieve in a cardiac rehabilitation program (t(29) = 14.73, P < 0.001). We conclude that police work requires a functional capacity greater than that typically attained in traditional cardiac rehabilitation programs. Rehabilitation professionals should consider performing maximal stress tests and increasing the intensity of cardiac rehabilitation workouts to effectively train police officers who have had a cardiac event. PMID:20157495

  18. 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.

  19. Biasing the pacemaker in the behavioral theory of timing

    PubMed Central

    Bizo, Lewis A.; White, K. Geoffrey

    1995-01-01

    In the behavioral theory of timing, pacemaker rate is determined by overall rate of reinforcement. A two-alternative free-operant psychophysical procedure was employed to investigate whether pacemaker period was also sensitive to the differential rate of reinforcement. Responding on a left key during the first 25 s and on a right key during the second 25 s of a 50-s trial was reinforced at variable intervals, and variable-interval schedule values during the two halves of the trials were varied systematically. Responding on the right key during the first 25 s and on the left key during the second 25 s was not reinforced. Estimates of pacemaker period were derived from fits of a function predicted by the behavioral theory of timing to right-key response proportions in consecutive 5-s bins of the 50-s trial. Estimates of pacemaker period were shortest when the differential reinforcer rate most strongly favored right-key responses, and were longest when the differential reinforcer rate most strongly favored left-key responses. The results were consistent with the conclusion that pacemaker rate is influenced by relative reinforcer rate. PMID:16812769

  20. 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.

  1. Electroacupuncture on a patient with pacemaker: a case report.

    PubMed

    Vasilakos, Dimitrios G; Fyntanidou, Barbara P

    2011-06-01

    Electroacupuncture (EA) is commonly used for pain relief, with good results even in persistent chronic pain. However, published reports suggest that EA should not be used in patients who have pacemaker, since there is a theoretical risk of malfunction of the pacemaker. The case is described of a 50-year-old female patient, who has had severe low back pain resistant both to conventional and unconventional treatment methods. The only treatment that seemed to have some positive effect, but of extremely short duration, was acupuncture. Her condition deteriorated considerably, and after due consideration she was treated with EA. Even after the first EA treatment, the patient's condition improved. Since then, she has received many EA courses during the past 2 years without any complications or side effects. The results of this case study suggest that EA might be a safe alternative for patients with a pacemaker, confirming the current recommendations on use. Every patient should be considered with care, individually. PMID:21386114

  2. [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. PMID:26631083

  3. Onboarding advanced practice nurses: development of an orientation program in a cardiac center.

    PubMed

    Goldschmidt, Karen; Rust, Donna; Torowicz, Deborah; Kolb, Susan

    2011-01-01

    The advanced practice nurse (APN) is critical to continuity of patient care, particularly in an innovative and research-intensive environment. The intensity of the environment, steep learning curve, and lack of a structured orientation can lead to difficulties in role assimilation and feelings of disconnectedness. This led the authors to undertake an improvement project to develop an onboarding program for APNs and develop strategies to orient them to their role. The authors describe the program and discuss how it was perceived by the APNs. Program evaluation and suggestions for future nursing research are identified. PMID:21157242

  4. [Practical questions around individual with a pacemaker or an implantable cardioverter defibrillator].

    PubMed

    Manaouil, Cécile; Fantoni, Sophie; Montpellier, Dominique; Tordjman, Eric; Jarde, Olivier

    2012-07-01

    An individual with a pacemaker can ask his GP for information about potential problems associated with the device. Should a pacemaker continue to be used by end-of-life patients? Should a pacemaker be stopped in a limited care situation? What precautions should be taken when treating a patient with a pacemaker? Pacemakers and implantable defibrillators are sensitive to electromagnetic interference (EMI). Medically, MRIs are theoretically contraindicated, even though examinations could be performed without a major problem, and special precautions should be taken when using an electrosurgical cutter or radiotherapy. In case of death, a doctor or embalmer must remove the patient's pacemaker due to its risk of explosion during cremation. Doctors who sign cremation forms have a legal obligation to provide such information. It may affect an employee's ability to work. Are there some professions that are not well suited for individuals with a pacemaker? PMID:22138293

  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. PMID:26593140

  6. A chance-constrained programming approach to preoperative planning of robotic cardiac surgery under task-level uncertainty.

    PubMed

    Azimian, Hamidreza; Naish, Michael D; Kiaii, Bob; Patel, Rajni V

    2015-03-01

    In this paper, a novel formulation for robust surgical planning of robotics-assisted minimally invasive cardiac surgery based on patient-specific preoperative images is proposed. In this context, robustness is quantified in terms of the likelihood of intraoperative collisions and of joint limit violations. The proposed approach provides a more accurate and complete formulation than existing deterministic approaches in addressing uncertainty at the task level. Moreover, it is demonstrated that the dexterity of robotic arms can be quantified as a cross-entropy term. The resulting planning problem is rendered as a chance-constrained entropy maximization problem seeking a plan with the least susceptibility toward uncertainty at the task level, while maximizing the dexterity (cross-entropy term). By such treatment of uncertainty at the task level, spatial uncertainty pertaining to mismatches between the patient-specific anatomical model and that of the actual intraoperative situation is also indirectly addressed. As a solution method, the unscented transform is adopted to efficiently transform the resulting chance-constrained entropy maximization problem into a constrained nonlinear program without resorting to computationally expensive particle-based methods. PMID:24718580

  7. 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)

  8. Differentially Timed Extracellular Signals Synchronize Pacemaker Neuron Clocks

    PubMed Central

    Collins, Ben; Kaplan, Harris S.; Cavey, Matthieu; Lelito, Katherine R.; Bahle, Andrew H.; Zhu, Zhonghua; Macara, Ann Marie; Roman, Gregg; Shafer, Orie T.; Blau, Justin

    2014-01-01

    Synchronized neuronal activity is vital for complex processes like behavior. Circadian pacemaker neurons offer an unusual opportunity to study synchrony as their molecular clocks oscillate in phase over an extended timeframe (24 h). To identify where, when, and how synchronizing signals are perceived, we first studied the minimal clock neural circuit in Drosophila larvae, manipulating either the four master pacemaker neurons (LNvs) or two dorsal clock neurons (DN1s). Unexpectedly, we found that the PDF Receptor (PdfR) is required in both LNvs and DN1s to maintain synchronized LNv clocks. We also found that glutamate is a second synchronizing signal that is released from DN1s and perceived in LNvs via the metabotropic glutamate receptor (mGluRA). Because simultaneously reducing Pdfr and mGluRA expression in LNvs severely dampened Timeless clock protein oscillations, we conclude that the master pacemaker LNvs require extracellular signals to function normally. These two synchronizing signals are released at opposite times of day and drive cAMP oscillations in LNvs. Finally we found that PdfR and mGluRA also help synchronize Timeless oscillations in adult s-LNvs. We propose that differentially timed signals that drive cAMP oscillations and synchronize pacemaker neurons in circadian neural circuits will be conserved across species. PMID:25268747

  9. 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 Central

    Cottrell, Lesley; Murphy, Emily; Lilly, Christa L.; Ritchie, Susan K.; 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. PMID:23840946

  10. 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. PMID:22433577

  11. Overdrive suppression of implanted pacemakers in patients with AV block.

    PubMed Central

    Grendahl, H; Miller, M; Kjekshus, J

    1978-01-01

    Patients being permanently paced for symptomatic AV block were studied by overdrive suppression of the QRS-inhibited pacemaker, in order to observe the underlying heart rhythm. The chest wall stimulation method was used. In complete AV block the escape rhythm recovery time proved highly reproducible on repeated testing on the same day, and in many patients remained so over months or years. Occasionally, a doubling of the escape rhythm recovery time was seen, suggesting initial exit block of the escape focus. Resetting of the escape rhythm usually followed an exponential curve until stabilisation after about 3 minutes. An early escape rhythm with a recovery time of less than 4 seconds was found on every occasion in 21 of 58 patients with complete AV block, and inconstantly in 23 more; in 14 it was never observed. Accidental pacing failure was seen in 15 patients. The overdrive suppression test was helpful in selecting pacemaker dependent patients. PMID:637960

  12. Cardiac Catheterization

    MedlinePLUS

    ... done during a cardiac catheterization include: closing small holes inside the heart repairing leaky or narrow heart ... bandage. It's normal for the site to be black and blue, red, or slightly swollen for a ...

  13. Serotonin augments gut pacemaker activity via 5-HT3 receptors.

    PubMed

    Liu, Hong-Nian; Ohya, Susumu; Nishizawa, Yuji; Sawamura, Kenta; Iino, Satoshi; Syed, Mohsin Md; Goto, Kazunori; Imaizumi, Yuji; Nakayama, Shinsuke

    2011-01-01

    Serotonin (5-hydroxytryptamine: 5-HT) affects numerous functions in the gut, such as secretion, muscle contraction, and enteric nervous activity, and therefore to clarify details of 5-HT's actions leads to good therapeutic strategies for gut functional disorders. The role of interstitial cells of Cajal (ICC), as pacemaker cells, has been recognised relatively recently. We thus investigated 5-HT actions on ICC pacemaker activity. Muscle preparations with myenteric plexus were isolated from the murine ileum. Spatio-temporal measurements of intracellular Ca(2+) and electric activities in ICC were performed by employing fluorescent Ca(2+) imaging and microelectrode array (MEA) systems, respectively. Dihydropyridine (DHP) Ca(2+) antagonists and tetrodotoxin (TTX) were applied to suppress smooth muscle and nerve activities, respectively. 5-HT significantly enhanced spontaneous Ca(2+) oscillations that are considered to underlie electric pacemaker activity in ICC. LY-278584, a 5-HT(3) receptor antagonist suppressed spontaneous Ca(2+) activity in ICC, while 2-methylserotonin (2-Me-5-HT), a 5-HT(3) receptor agonist, restored it. GR113808, a selective antagonist for 5-HT(4), and O-methyl-5-HT (O-Me-5-HT), a non-selective 5-HT receptor agonist lacking affinity for 5-HT(3) receptors, had little effect on ICC Ca(2+) activity. In MEA measurements of ICC electric activity, 5-HT and 2-Me-5-HT caused excitatory effects. RT-PCR and immunostaining confirmed expression of 5-HT(3) receptors in ICC. The results indicate that 5-HT augments ICC pacemaker activity via 5-HT(3) receptors. ICC appear to be a promising target for treatment of functional motility disorders of the gut, for example, irritable bowel syndrome. PMID:21949791

  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. Inhibition of a Demand Pacemaker and Interference with Monitoring Equipment by Radio-frequency Transmissions

    PubMed Central

    Pickers, Bryan A.; Goldberg, M. J.

    1969-01-01

    During the initial testing of Radio Leicester a swept-frequency technique for testing radio antennae was shown to affect demand pacemakers by inhibition of the pacing impulse and to interfere with physiological monitoring equipment. Adequate filtering of demand pacemakers is necessary to eliminate this interference. There is no evidence that such testing has any effect on the function of fixed-rate pacemakers. There is also a potential danger to implanted demand pacemakers by the use of similar polyscope generators used for servicing radio and television apparatus in industry. PMID:5771585

  16. 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.

  17. Dual antiplatelet therapy increases pocket hematoma complications in Chinese patients with pacemaker implantation

    PubMed Central

    Dai, Yan; Chen, Ke-Ping; Hua, Wei; Zhang, Jing-Tao; Zhang, Shu

    2015-01-01

    Objective To assess the prevalence of the bleeding complications in pacemaker implanted patients receiving different antiplatelet regimens, and the influence of each regimen on hospital stays after device implantation. Methods We prospectively enrolled 364 patients receiving the cardiac rhythm device implantations in Fuwai Hospital from July 2012 to December 2013. Bleeding complications including pocket hematoma, hemothorax, cardiac tamponade and blood transfusion requirement were measured as endpoints. Post operation hospital stay was also included in the endpoints. Results Bleeding complications were detected in 15 patients (14 with hematoma, one with hemothorax) out of all 364 patients (4.12%). Dual antiplatelet therapy (DAT) significantly increased hematoma (19.3%) compared with aspirin treatment (ASA) (3.2%, P = 0.001) and no antiplatelet therapy (1.9%, P < 0.001). There was no significant difference in incidence of pocket hematoma between the ASA group and the control group (P = 0.45). The post procedure hospital stay was longer in DAT group (5.45 ± 2.01 days) compared to those in the ASA group (3.65 ± 1.37 days, P < 0.05) or control group (3.99 ± 2.27 days, P < 0.05). Pocket hematoma was considered an independent predictor of hospital stay prolongation (OR: 5.26; 95% CI: 1.56?16.64; P = 0.007). Conclusions Among the Chinese patients undergoing device implantation in this study, the use of dual antiplatelet agents significantly increased the risk of pocket hematoma complications and led to a longer hospital stay. Use of aspirin alone did not increase the risk. PMID:26347068

  18. A Comparative Survey of Pacemaker Implantation in Trinidad and Tobago in 2005 and 2009

    PubMed Central

    Henry, R; Dookie, T; Primus, E

    2014-01-01

    ABSTRACT Objective: The indications for permanent pacemaker implantations in Trinidad have expanded from initially symptomatic bradycardia to now include complex devices. A retrospective review of the available data was conducted to better understand the evolving trends in device implantation in Trinidad and Tobago. Methods: Data were collated from the two major implanting teams in Trinidad for the years 2005 and 2009. The two implanting centres were the Advanced Cardiovascular Institute (ACI) at Westshore Medical Centre and the Catheterization Laboratory of the Eric Williams Medical Sciences Complex (EWMSC). Data were based on retrospective collation using the implantation records. Results: The implantation rate for new devices increased from 39 per million to 103 per million population. The most common indications for new device implants in 2009 were high degree atrioventricular (AV) block (53%) and sick sinus syndrome (22%), with the notable appearance of congestive cardiomyopathy (13%) which was not present in the earlier cohort. Of particular note, 23 high-end devices were implanted in 2009. These were five cardiac-resynchronization therapy (CRT-P) devices, 14 automatic implantable cardio-defibrillator (AICD) devices and four combined cardiac-resynchronization therapy with defibrillator (CRT-D) devices versus none in 2005. Conclusions: In summary, over the period 2005 to 2009, a substantial increase in device implantation rates has occurred which now include high-end complex devices. Absolute rates, however, remain far below that of developed countries, indicating that the true need remains underserved. Furthermore, adjustment for gross domestic product suggests that the relatively buoyant economy of Trinidad and Tobago is capable of servicing a greater proportion of this need than is currently met. PMID:26108119

  19. "Subclinical" pacemaker syndrome: a randomised study of symptom free patients with ventricular demand (VVI) pacemakers upgraded to dual chamber devices.

    PubMed Central

    Sulke, N; Dritsas, A; Bostock, J; Wells, A; Morris, R; Sowton, E

    1992-01-01

    OBJECTIVE--To determine whether symptom free patients with single chamber pacemakers benefit from dual chamber pacing. DESIGN--A randomised double blind crossover comparison of ventricular demand (VVI), dual chamber demand (DDI), and dual chamber universal (DDD) modes after upgrading from a VVI device. SETTING--Cardiology outpatient department. PATIENTS--Sixteen patients aged 41-84 years who were symptom free during VVI mode pacing for three or more years. INTERVENTION--Pacemaker upgrade during routine generator change. MAIN OUTCOME MEASURES--Change in subjective (general health perception, symptoms) and objective (clinical assessment, treadmill exercise, and radiological and echocardiographic indices) results between pacing modes before and after upgrading. RESULTS--75% preferred DDD, 68% found VVI least acceptable with 12% expressing no preference. Perceived general well-being and exercise capacity (p less than 0.01) and treadmill times (p less than 0.05) were improved in DDD mode but VVI and DDI modes were similar. Clinical, echocardiographic, radiological, and electrophysiological indices confirmed the absence of overt pacemaker syndrome, although mitral and tricuspid regurgitation was greatest in VVI mode (p less than 0.01). CONCLUSIONS--Most patients who were satisfied with long term pacing in VVI mode benefited from upgrading to DDD mode pacing suggesting the existence of "subclinical" pacemaker syndrome in up to 75% of such patients. The DDI mode offered little subjective or objective benefit over VVI mode in this population and should be reserved for patients with paroxysmal atrial arrhythmias. VVI mode pacing should be used only for patients with very intermittent symptomatic bradycardia or atrial fibrillation with a good chronotropic response during exercise. PMID:1739528

  20. High-intensity cardiac rehabilitation training of a commercial pilot who, after percutaneous coronary intervention, wanted to continue participating in a rigorous strength and conditioning program.

    PubMed

    Shrestha, Sanjay; Adams, Jenny; Lawrence, Anne; Schussler, Jeffrey M

    2016-01-01

    After undergoing elective percutaneous coronary intervention, a 64-year-old commercial pilot was referred to cardiac rehabilitation. His stated goals were to continue participating in a rigorous strength and conditioning program at a community workout facility and to resume working as a pilot. To help him meet those goals, we designed and implemented a regimen of high-intensity exercises, with quick transitions between a variety of tasks that are not typically included in cardiac rehabilitation programs (e.g., medicine ball throws, push-ups, dead lifts, squats, military presses, sprints, and lunges). The training was symptom limited, enabling the patient to reach extreme levels of physical exertion in a controlled, monitored setting. By studying his training data (heart rate, blood pressure, and rating of perceived exertion), we were able to give him specific recommendations for controlling his exercise intensity after graduating from our program. More than 18 months later, he continues to exercise vigorously 3 days per week and is working as a commercial pilot. PMID:26722183

  1. Injury to the coronary arteries and related structures by implantation of cardiac implantable electronic devices.

    PubMed

    Pang, Benjamin J; Barold, S Serge; Mond, Harry G

    2015-04-01

    Damage to the coronary arteries and related structures from pacemaker and implantable cardioverter-defibrillator lead implantation is a rarely reported complication that can lead to myocardial infarction and pericardial tamponade that may occur acutely or even years later. We summarize the reported cases of injury to coronary arteries and related structures and review the causes of troponin elevation in the setting of cardiac implantable electronic device implantation. PMID:25564549

  2. Connectivity of pacemaker neurons in the neonatal rat superficial dorsal horn.

    PubMed

    Li, Jie; Kritzer, Elizabeth; Ford, Neil C; Arbabi, Shahriar; Baccei, Mark L

    2015-05-01

    Pacemaker neurons with an intrinsic ability to generate rhythmic burst-firing have been characterized in lamina I of the neonatal spinal cord, where they are innervated by high-threshold sensory afferents. However, little is known about the output of these pacemakers, as the neuronal populations that are targeted by pacemaker axons have yet to be identified. The present study combines patch-clamp recordings in the intact neonatal rat spinal cord with tract-tracing to demonstrate that lamina I pacemaker neurons contact multiple spinal motor pathways during early life. Retrograde labeling of premotor interneurons with the trans-synaptic pseudorabies virus PRV-152 revealed the presence of burst-firing in PRV-infected lamina I neurons, thereby confirming that pacemakers are synaptically coupled to motor networks in the spinal ventral horn. Notably, two classes of pacemakers could be distinguished in lamina I based on cell size and the pattern of their axonal projections. Whereas small pacemaker neurons possessed ramified axons that contacted ipsilateral motor circuits, large pacemaker neurons had unbranched axons that crossed the midline and ascended rostrally in the contralateral white matter. Recordings from identified spino-parabrachial and spino-periaqueductal gray neurons indicated the presence of pacemaker activity within neonatal lamina I projection neurons. Overall, these results show that lamina I pacemakers are positioned to regulate both the level of activity in developing motor circuits and the ascending flow of nociceptive information to the brain, thus highlighting a potential role for pacemaker activity in the maturation of pain and sensorimotor networks in the central nervous system. PMID:25380417

  3. Evaluation of the Genetic Basis of Familial Aggregation of Pacemaker Implantation by a Large Next Generation Sequencing Panel

    PubMed Central

    Steiner, Hillel A.; Uradu, Andrea; Lynnes, Ty C.; Groh, William J.; Miller, John M.; Lin, Hai; Gao, Hongyu; Wang, Zhiping; Liu, Yunlong; Chen, Peng-Sheng; Vatta, Matteo

    2015-01-01

    Background The etiology of conduction disturbances necessitating permanent pacemaker (PPM) implantation is often unknown, although familial aggregation of PPM (faPPM) suggests a possible genetic basis. We developed a pan-cardiovascular next generation sequencing (NGS) panel to genetically characterize a selected cohort of faPPM. Materials and Methods We designed and validated a custom NGS panel targeting the coding and splicing regions of 246 genes with involvement in cardiac pathogenicity. We enrolled 112 PPM patients and selected nine (8%) with faPPM to be analyzed by NGS. Results Our NGS panel covers 95% of the intended target with an average of 229x read depth at a minimum of 15-fold depth, reaching a SNP true positive rate of 98%. The faPPM patients presented with isolated cardiac conduction disease (ICCD) or sick sinus syndrome (SSS) without overt structural heart disease or identifiable secondary etiology. Three patients (33.3%) had heterozygous deleterious variants previously reported in autosomal dominant cardiac diseases including CCD: LDB3 (p.D117N) and TRPM4 (p.G844D) variants in patient 4; TRPM4 (p.G844D) and ABCC9 (p.V734I) variants in patient 6; and SCN5A (p.T220I) and APOB (p.R3527Q) variants in patient 7. Conclusion FaPPM occurred in 8% of our PPM clinic population. The employment of massive parallel sequencing for a large selected panel of cardiovascular genes identified a high percentage (33.3%) of the faPPM patients with deleterious variants previously reported in autosomal dominant cardiac diseases, suggesting that genetic variants may play a role in faPPM. PMID:26636822

  4. Mechanism of programmed cell death factor 4/nuclear factor-?B signaling pathway in porcine coronary micro-embolization-induced cardiac dysfunction.

    PubMed

    Su, Qiang; Li, Lang; Wang, Jiangyou; Zhou, You; Liu, Yangchun

    2015-11-01

    The aim of this study was to investigate the role of the programmed cell death factor 4 (PDCD4)/nuclear factor-?B (NF-?B) signaling pathway in coronary micro-embolism (CME)-induced inflammatory responses and cardiac dysfunction in a porcine model. Bama miniature pigs were randomly divided into four groups (n?=?5 per group). Micro-embolization balls or saline were infused through a microcatheter in the left anterior descending (LAD) artery in the CME and Sham groups, respectively. PDCD4 siRNA or control siRNA mixed with transfection reagent was infused via the LAD artery 72?h before CME induction in the CME + siRNA-PDCD4 and siRNA-control groups, respectively. Cardiac function was evaluated with ultrasound. Tissue biopsy was stained with hematoxylin-eosin (HE) and hematoxylin basic fuchsin picric acid (HBFP) to measure infarction area. Myocardial PDCD4 and tumor necrosis factor-? (TNF-?) mRNA and protein expression were analyzed by quantitative PCR and Western blotting. NF-?B activity was evaluated in gel electrophoretic mobility shift assay. Echocardiographic parameters showed that compared with the sham group, the CME group had impaired heart function, manifested as systolic dysfunction and left ventricular dilatation (reduced left ventricular ejection fraction [LVEF], left ventricular fractional shortening [FS], and cardiac output [CO] [P?cardiac function damage (increased LVEF, FS and CO [P?cardiac dysfunction, suggesting that inhibition of PDCD4/NF-?B signaling pathway may be a potential target for the prevention and treatment of CME. PMID:25769315

  5. Why the Authors Use Cardiac Resynchronization Therapy with Defibrillators.

    PubMed

    Sze, Edward; Daubert, James P

    2015-12-01

    Cardiac resynchronization therapy (CRT) improves left ventricular function, especially in patients with left bundle branch block or those receiving chronic right ventricular pacing. CRT is typically accomplished by placing a right ventricular endocardial pacing lead and a left ventricular pacing lead via the coronary sinus to a coronary vein overlying the lateral or posterolateral left ventricle. CRT can be combined with an implantable defibrillator or with a pacemaker. Limited data are available to compare these two versions of CRT head to head. This review summarizes the relevant trials and meta-analyses regarding these two forms of CRT. PMID:26596812

  6. Circadian Activators Are Expressed Days before They Initiate Clock Function in Late Pacemaker Neurons from Drosophila.

    PubMed

    Liu, Tianxin; Mahesh, Guruswamy; Houl, Jerry H; Hardin, Paul E

    2015-06-01

    Circadian pacemaker neurons in the Drosophila brain control daily rhythms in locomotor activity. These pacemaker neurons can be subdivided into early or late groups depending on whether rhythms in period (per) and timeless (tim) expression are initiated at the first instar (L1) larval stage or during metamorphosis, respectively. Because CLOCK-CYCLE (CLK-CYC) heterodimers initiate circadian oscillator function by activating per and tim transcription, a Clk-GFP transgene was used to mark when late pacemaker neurons begin to develop. We were surprised to see that CLK-GFP was already expressed in four of five clusters of late pacemaker neurons during the third instar (L3) larval stage. CLK-GFP is only detected in postmitotic neurons from L3 larvae, suggesting that these four late pacemaker neuron clusters are formed before the L3 larval stage. A GFP-cyc transgene was used to show that CYC, like CLK, is also expressed exclusively in pacemaker neurons from L3 larval brains, demonstrating that CLK-CYC is not sufficient to activate per and tim in late pacemaker neurons at the L3 larval stage. These results suggest that most late pacemaker neurons develop days before novel factors activate circadian oscillator function during metamorphosis. PMID:26041931

  7. Cardiac Rehabilitation

    MedlinePLUS

    ... prevent future heart problems and even death. Exercise training as part of cardiac rehab might not be safe for all patients. For example, if you have very high blood pressure or severe heart disease, you might not be ready for exercise. However, ...

  8. A novel curve fitting method for AV optimisation of biventricular pacemakers.

    PubMed

    Dehbi, Hakim-Moulay; Jones, Siana; Sohaib, S M Afzal; Finegold, Judith A; Siggers, Jennifer H; Stegemann, Berthold; Whinnett, Zachary I; Francis, Darrel P

    2015-09-01

    In this study, we designed and tested a new algorithm, which we call the 'restricted parabola', to identify the optimum atrioventricular (AV) delay in patients with biventricular pacemakers. This algorithm automatically restricts the hemodynamic data used for curve fitting to the parabolic zone in order to avoid inadvertently selecting an AV optimum that is too long.We used R, a programming language and software environment for statistical computing, to create an algorithm which applies multiple different cut-offs to partition curve fitting of a dataset into a parabolic and a plateau region and then selects the best cut-off using a least squares method. In 82 patients, AV delay was adjusted and beat-to-beat systolic blood pressure (SBP) was measured non-invasively using our multiple-repetition protocol. The novel algorithm was compared to fitting a parabola across the whole dataset to identify how many patients had a plateau region, and whether a higher hemodynamic response was achieved with one method.In 9/82 patients, the restricted parabola algorithm detected that the pattern was not parabolic at longer AV delays. For these patients, the optimal AV delay predicted by the restricted parabola algorithm increased SBP by 1.36?mmHg above that predicted by the conventional parabolic algorithm (95% confidence interval: 0.65 to 2.07?mmHg, p-value = 0.002).AV optima selected using our novel restricted parabola algorithm give a greater improvement in acute hemodynamics than fitting a parabola across all tested AV delays. Such an algorithm may assist the development of automated methods for biventricular pacemaker optimisation. PMID:26246270

  9. 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. PMID:22139782

  10. Mechanisms that match ATP supply to demand in cardiac pacemaker cells during high ATP demand

    PubMed Central

    Yaniv, Yael; Spurgeon, Harold A.; Ziman, Bruce D.; Lyashkov, Alexey E.

    2013-01-01

    The spontaneous action potential (AP) firing rate of sinoatrial node cells (SANCs) involves high-throughput signaling via Ca2+-calmodulin activated adenylyl cyclases (AC), cAMP-mediated protein kinase A (PKA), and Ca2+/calmodulin-dependent protein kinase II (CaMKII)-dependent phosphorylation of SR Ca2+ cycling and surface membrane ion channel proteins. When the throughput of this signaling increases, e.g., in response to ?-adrenergic receptor activation, the resultant increase in spontaneous AP firing rate increases the demand for ATP. We hypothesized that an increase of ATP production to match the increased ATP demand is achieved via a direct effect of increased mitochondrial Ca2+ (Ca2+m) and an indirect effect via enhanced Ca2+-cAMP/PKA-CaMKII signaling to mitochondria. To increase ATP demand, single isolated rabbit SANCs were superfused by physiological saline at 35 ± 0.5°C with isoproterenol, or by phosphodiesterase or protein phosphatase inhibition. We measured cytosolic and mitochondrial Ca2+ and flavoprotein fluorescence in single SANC, and we measured cAMP, ATP, and O2 consumption in SANC suspensions. Although the increase in spontaneous AP firing rate was accompanied by an increase in O2 consumption, the ATP level and flavoprotein fluorescence remained constant, indicating that ATP production had increased. Both Ca2+m and cAMP increased concurrently with the increase in AP firing rate. When Ca2+m was reduced by Ru360, the increase in spontaneous AP firing rate in response to isoproterenol was reduced by 25%. Thus, both an increase in Ca2+m and an increase in Ca2+ activated cAMP-PKA-CaMKII signaling regulate the increase in ATP supply to meet ATP demand above the basal level. PMID:23604710

  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 ?-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 O? consumption in SANC suspensions. Although the increase in spontaneous AP firing rate was accompanied by an increase in O? consumption, the ATP level and flavoprotein fluorescence remained constant, indicating that ATP production had increased. Both Ca(2+)m and cAMP increased concurrently with the increase in AP firing rate. When Ca(2+)m was reduced by Ru360, the increase in spontaneous AP firing rate in response to isoproterenol was reduced by 25%. Thus, both an increase in Ca(2+)m and an increase in Ca(2+) activated cAMP-PKA-CaMKII signaling regulate the increase in ATP supply to meet ATP demand above the basal level. PMID:23604710

  12. Liénard-type models for the simulation of the action potential of cardiac nodal cells

    NASA Astrophysics Data System (ADS)

    Podziemski, P.; ?ebrowski, J. J.

    2013-10-01

    Existing models of cardiac cells which include multi-variable cardiac transmembrane current are too complex to simulate the long time dynamical properties of the heart rhythm. The large number of parameters that need to be defined and set for such models make them not only cumbersome to use but also require a large computing power. Consequently, the application of such models for the bedside analysis of heart rate of a specific patient may be difficult. Other ways of modelling need to be investigated. We consider the general problem of developing a model of cardiac pacemaker tissue that allows to combine the investigation of phenomena at a time scale of thousands of heart beats with the ability to reproduce realistic tissue-level characteristics of cell dynamics. We propose a modified van der Pol-Duffing equation-a Liénard-type oscillator-as a phenomenological model for cardiac nodal tissue, with certain important physiological similarities to ion-channel models of cardiac pacemaker cells. The model presented here is specifically designed to qualitatively reproduce mesoscopic characteristics of cell dynamics, including action potential duration (APD) restitution properties, phase response characteristics, and phase space structure. We show that these characteristics agree qualitatively with the extensive ionic models and experimental results in the literature [Anumonwo et al., 1991, [33], Cao et al., 1999, [49], Coster and Celler, 2003, [31], Qu, 2004, [45], Tsalikakis et al., 2007, [32], Inada et al., 2009, [14], Qu et al., 2010, [50

  13. Effects of tertiapin-Q and ZD7288 on changes in sinoatrial pacemaker rhythm during vagal stimulation.

    PubMed

    Han, Su Young; Bolter, Chris P

    2015-12-01

    Heart rate slowing produced by cardiac parasympathetic (vagal) stimulation is thought to be the result of modulation of the acetylcholine-activated K(+) current (IK,ACh) and the pacemaker current (If) in sinoatrial (SAN) pacemaker cells. However, the contribution of these and other ion currents to vagal slowing is controversial. Here, we examined the contributions of IK,ACh and If to vagal slowing in 15 isolated, vagal-innervated preparations of guinea-pig atria, using 300nM tertiapin-Q (TQ) and 2?M ZD7288 to obtain full and substantial block of these currents, respectively. Blocking IK,ACh alone reduced atrial rate responses to 10-s trains of regular vagal stimulation (supramaximal stimulation, 2-ms duration, 1-10Hz) by ~50% (P<0.01; N=11); blocking If alone had no effect (N=7). Blocking both IK,ACh and If produced ~90% reduction (P<0.01; N=4). Atrial cycle length response to a single burst of vagal stimuli (3 stimuli at 50Hz), delivered at the optimum phase of the cycle was strongly suppressed by blocking IK,ACh (reduced by 98%; P<0.01; N=9), and modestly reduced by blocking If alone (by ~43%; P=0.20; N=6). The response was abolished by combined block of IK,ACh and If (P=0.04; N=4). Our data show that modulation of IK,ACh and If is sufficient to account for all the vagal slowing observed in this preparation. The vagally-induced negative shift in activation potential for If will be opposed by hyperpolarisation of SAN through activation of IK,ACh. Thus removal of IK,ACh by TQ may have exaggerated the overall contribution of If to vagal slowing. PMID:26549880

  14. 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

  15. 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.

  16. 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.

  17. The Australian history of cardiac pacing: memories from a bygone era.

    PubMed

    Mond, Harry G; Wickham, Geoffrey G; Sloman, J Graeme

    2012-06-01

    Although Dr Albert Hyman in New York is believed to have built the first cardiac pacemaker in 1932, he acknowledges Dr Mark Lidwell in Sydney, Australia as having not only built a pacemaker, but also successfully used it to resuscitate a newborn infant in or before 1929. Fully implantable pacemakers, however, were not possible until 1958, following the development of the silicon transistor. Within three years of that first implant, a pulse generator attached to epicardial leads was implanted at the Royal Melbourne Hospital. About the same time, an engineer in Sydney with intermittent complete heart block who had received epicardial leads and an external pulse generator proposed a simple sensing circuit, leading to the design of the first demand pacing system. By the mid 1960s, physicians were inserting transvenous leads in the right ventricle attached to pulse generators implanted in the anterior abdominal wall. In 1963, an Australian pacemaker company, Telectronics, was founded in Sydney. This innovative company-designed many of the features of transvenous leads and pulse generators we take for granted today. Australia also played a leading role in the design or early evaluation of the lithium power source, lead fixation, steroid elution, automatic anti-tachycardia pacing algorithms and the minute ventilation rate adaptive sensor. This manuscript describes the challenges and frustrations of those pioneers: physicians, surgeons and biomedical engineers. PMID:22033147

  18. Cardiac lipoma

    PubMed Central

    Ismail, Imtiaz; Al-Khafaji, Khalid; Mutyala, Monica; Aggarwal, Saurabh; Cotter, William; Hakim, Hosam; Khosla, Sandeep; Arora, Rohit

    2015-01-01

    Lipomas of the heart are encapsulated tumors that are composed primarily of mature fat cells. Cardiac lipomas can originate either from subendocardium (approximately 50%), subpericardium (25%), or from the myocardium (25%) and may be located more frequently in left ventricle or right atrium. We report a 74-year-old female who presented with dyspnea on exertion and was found to have 5×5 cm mass occupying most of the right atrium on a transesophageal echocardiogram. PMID:26486106

  19. 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

  20. 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

  1. 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

  2. [Syncope, conduction disorders. Controversial indications for cardiac stimulation].

    PubMed

    Lamaison, D; Motreff, P; Dauphin, C; Briand, F; Marcollet, P; Langlade, S; Lusson, J R; Cassagnes, J

    2000-04-01

    The objective of permanent pacemaker implantation is to provide against an increased risk of death or to improve quality of life by abolishing symptoms. In both cases, certain indications for pacing have clearly demonstrated to be strongly beneficial in well selected patients, but other are still controversial, due to the lack of convincing and converging published data, or to the absence of general consensus among specialists, or because selection criteria for pacing have been poorly defined. We try to clarify when to pace or not to pace in such conditions as first degree AV block, type I second degree AV block, intracardiac conduction defects, including those occurring at the acute stage of myocardial infarct or after cardiac surgery, sick sinus syndrome in cardiac transplant recipients, carotid sinus syndrome, vasovagal syncope, and unexplained syncopes. PMID:10816801

  3. 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. PMID:21616944

  4. The evolution of the cardiac implantable electronic device connector.

    PubMed

    Mond, Harry G; Helland, John R; Fischer, Avi

    2013-11-01

    Cardiac implantable electronic devices (CIEDs) play a vital role in the management of cardiac rhythm disturbances. The devices are comprised of two primary components: a generator and lead joined by a connector. Original pacemaker lead connectors were created de novo at the time of implantation or replacement and were very unreliable. With the development of new lead designs, creation of a standard connector configuration, the IS-1 connector became mandatory. Similar connector development also occurred with the advent of the implantable cardioverter defibrillator (ICD), resulting in creation of the high voltage standard: the DF-1 connector. Differing from a pacemaker lead, the ICD lead connector requires one IS-1 connector and one or two DF-1 connectors, resulting in a large cumbersome lead connector and generator header block. Recently, a revolutionary quad pole single plug connector standard has been approved for market release. These are the single-pin DF4 and IS4 lead connectors that carry low- and high-voltage poles or all low-voltage poles, respectively. These connectors, together with new labeling guidelines, have simplified operative procedures and reduced errors, when mating lead connectors into the generator's connector block. PMID:23808816

  5. A preview of implantable cardioverter defibrillator systems in the next millennium: an integrative cardiac rhythm management approach.

    PubMed

    Morris, M M; KenKnight, B H; Warren, J A; Lang, D J

    1999-03-11

    The implantable cardioverter defibrillator (ICD), a primary therapeutic option for preventing sudden cardiac death, has rapidly evolved since being introduced clinically in 1980. Technologic advances in several key areas have enabled ICDs to provide more sophisticated rhythm management. Recent emphasis has been placed on dual-chamber ICDs possessing adaptive-rate pacing capabilities. Adoption of dual-chamber ICD systems has been rapid. The capabilities of future ICD systems will be governed by an integrative strategy that brings together sets of features specifically targeted at multifaceted rhythm disorders. The addition of atrial therapy will require more sophisticated rhythm discrimination algorithms. ICD technology will improve on several fronts including leads, integrated circuits, batteries, and capacitors. Additionally, state-of-the-art pacemaker technology will continue to be incorporated into ICDs. As these new ICD systems become increasingly sophisticated from an engineering viewpoint, tremendous emphasis will be placed on decreasing the complexity of programming, device interrogation, and patient monitoring during routine patient follow-up. Vast improvements in ICD programming systems may ultimately permit the 1-minute follow-up. PMID:10089840

  6. 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 ?Gy/mGy (RAO, third trimester). DAP normalized doses ranged from 0.051 (PA, first trimester) to 12.852 ?Gy/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)

  7. Optogenetics-enabled assessment of viral gene and cell therapy for restoration of cardiac excitability

    PubMed Central

    Ambrosi, Christina M.; Boyle, Patrick M.; Chen, Kay; Trayanova, Natalia A.; Entcheva, Emilia

    2015-01-01

    Multiple cardiac pathologies are accompanied by loss of tissue excitability, which leads to a range of heart rhythm disorders (arrhythmias). In addition to electronic device therapy (i.e. implantable pacemakers and cardioverter/defibrillators), biological approaches have recently been explored to restore pacemaking ability and to correct conduction slowing in the heart by delivering excitatory ion channels or ion channel agonists. Using optogenetics as a tool to selectively interrogate only cells transduced to produce an exogenous excitatory ion current, we experimentally and computationally quantify the efficiency of such biological approaches in rescuing cardiac excitability as a function of the mode of application (viral gene delivery or cell delivery) and the geometry of the transduced region (focal or spatially-distributed). We demonstrate that for each configuration (delivery mode and spatial pattern), the optical energy needed to excite can be used to predict therapeutic efficiency of excitability restoration. Taken directly, these results can help guide optogenetic interventions for light-based control of cardiac excitation. More generally, our findings can help optimize gene therapy for restoration of cardiac excitability. PMID:26621212

  8. Optogenetics-enabled assessment of viral gene and cell therapy for restoration of cardiac excitability.

    PubMed

    Ambrosi, Christina M; Boyle, Patrick M; Chen, Kay; Trayanova, Natalia A; Entcheva, Emilia

    2015-01-01

    Multiple cardiac pathologies are accompanied by loss of tissue excitability, which leads to a range of heart rhythm disorders (arrhythmias). In addition to electronic device therapy (i.e. implantable pacemakers and cardioverter/defibrillators), biological approaches have recently been explored to restore pacemaking ability and to correct conduction slowing in the heart by delivering excitatory ion channels or ion channel agonists. Using optogenetics as a tool to selectively interrogate only cells transduced to produce an exogenous excitatory ion current, we experimentally and computationally quantify the efficiency of such biological approaches in rescuing cardiac excitability as a function of the mode of application (viral gene delivery or cell delivery) and the geometry of the transduced region (focal or spatially-distributed). We demonstrate that for each configuration (delivery mode and spatial pattern), the optical energy needed to excite can be used to predict therapeutic efficiency of excitability restoration. Taken directly, these results can help guide optogenetic interventions for light-based control of cardiac excitation. More generally, our findings can help optimize gene therapy for restoration of cardiac excitability. PMID:26621212

  9. Circadian clock and cardiac vulnerability: A time stamp on multi-scale neuroautonomic regulation

    NASA Astrophysics Data System (ADS)

    Ivanov, Plamen Ch.

    2005-03-01

    Cardiovascular vulnerability displays a 24-hour pattern with a peak between 9AM and 11AM. This daily pattern in cardiac risk is traditionally attributed to external factors including activity levels and sleep-wake cycles. However,influences from the endogenous circadian pacemaker independent from behaviors may also affect cardiac control. We investigate heartbeat dynamics in healthy subjects recorded throughout a 10-day protocol wherein the sleep/wake and behavior cycles are desynchronized from the endogenous circadian cycle,enabling assessment of circadian factors while controlling for behavior-related factors. We demonstrate that the scaling exponent characterizing temporal correlations in heartbeat dynamics over multiple time scales does exhibit a significant circadian rhythm with a sharp peak at the circadian phase corresponding to the period 9-11AM, and that this rhythm is independent from scheduled behaviors and mean heart rate. Our findings of strong circadian rhythms in the multi-scale heartbeat dynamics of healthy young subjects indicate that the underlying mechanism of cardiac regulation is strongly influenced by the endogenous circadian pacemaker. A similar circadian effect in vulnerable individuals with underlying cardiovascular disease would contribute to the morning peak of adverse cardiac events observed in epidemiological studies.

  10. Hyperpolarization-Activated Current, If, in Mathematical Models of Rabbit Sinoatrial Node Pacemaker Cells

    PubMed Central

    Verkerk, Arie O.

    2013-01-01

    A typical feature of sinoatrial (SA) node pacemaker cells is the presence of an ionic current that activates upon hyperpolarization. The role of this hyperpolarization-activated current, If, which is also known as the “funny current” or “pacemaker current,” in the spontaneous pacemaker activity of SA nodal cells remains a matter of intense debate. Whereas some conclude that If plays a fundamental role in the generation of pacemaker activity and its rate control, others conclude that the role of If is limited to a modest contribution to rate control. The ongoing debate is often accompanied with arguments from computer simulations, either to support one's personal view or to invalidate that of the antagonist. In the present paper, we review the various mathematical descriptions of If that have been used in computer simulations and compare their strikingly different characteristics with our experimental data. We identify caveats and propose a novel model for If based on our experimental data. PMID:23936852

  11. Follower Neurons in Lobster (Panulirus interruptus) Pyloric Network Regulate Pacemaker Period in Complementary Ways

    E-print Network

    Hooper, Scott

    Follower Neurons in Lobster (Panulirus interruptus) Pyloric Network Regulate Pacemaker Period November 2002 Weaver, Adam L. and Scott L. Hooper. Follower neurons in lobster (Panulirus interruptus levels of interconnectiv- ity among network neurons) are not well understood. Increased insight

  12. Currents induced by fast movements inside the MRI room may cause inhibition in an implanted pacemaker.

    PubMed

    Mattei, Eugenio; Censi, Federica; Mancini, Matteo; Napolitano, Antonio; Genovese, Elisabetta; Cannata, Vittorio; Burriesci, Giancarlo; Falsaperla, Rosaria; Calcagnini, Giovanni

    2014-08-01

    The static magnetic field generated by MRI systems is highly non-homogenous and rapidly decreases when moving away from the bore of the scanner. Consequently, the movement around the MRI scanner is equivalent to an exposure to a time-varying magnetic field at very low frequency (few Hz). If people with an implanted pacemaker (PM) enter the MRI room, fast movements may thus induce voltages on the loop formed by the PM lead, with the potential to modify the correct behavior of the stimulator. In this study, we performed in-vitro measurements on a human-shaped phantom, equipped with an implantable PM and with a current sensor, able to monitor the activity of the PM while moving the phantom in the MRI room. Fast rotational movements in close proximity of the bore of the scanner caused the inappropriate inhibition of the PM, programmed in VVI modality, maximum sensitivity, unipolar sensing and pacing. The inhibition occurred for a variation of the magnetic field of about 3 T/s. These findings demonstrate that great care must be paid when extending PM MRI compatibility from patients to healthcare personnel, since the safety procedures and the MRI-conditional PM programming (e.g. asynchronous stimulation or bipolar sensing) used for patients cannot be applied. PMID:25570102

  13. False inhibition of an atrial demand pacemaker caused by an insulation defect in a polyurethane lead.

    PubMed

    van Gelder, L M; El Gamal, M I

    1983-09-01

    A patient who had an atrial demand pacemaker (AAI) presented with irregular pacing at a routine examination 5 months after implantation. When a magnet was applied over the pulse generator regular fixed rate pacing was obtained, thus proving oversensing in the system. Reprogramming the input sensitivity level to 2.5 and 5.0 mV did not solve the problem. Programming the pulse generator to the triggered mode (AAT) showed acceleration of the stimulation rate but also inhibition of the system. An S-S interval of 1260 ms was measured at a programmed interval of 857 ms (70 bpm). The pulse generator was disconnected and the intra-atrial electrogram was recorded. This showed different spurious signals varying in morphology and amplitude. Fortunately we were able to remove the lead (Medtronic 6991-U) from the atrial appendage. Subsequently a Helifix 12 mm AT lead was successfully implanted in the right atrial appendage and the same pulse generator was connected to the newly implanted lead. When the removed lead was examined by the manufacturer, a small tear in the insulation of the wire was detected. The dimensions of the tear were 0.1 X 0.7 mm. The tear was caused by stress corrosion cracking in the polyurethane tubing of the lead. PMID:6195601

  14. A Fully Implantable Pacemaker for the Mouse: From Battery to Wireless Power

    PubMed Central

    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. PMID:24194832

  15. A Case of Late Implantable Cardiac Device Infection with Aspergillus in an Immunocompetent Host

    PubMed Central

    Kodali, Archana; Khalighi, Koroush

    2015-01-01

    Patient: Female, 67 Final Diagnosis: Infected pacemaker device secondary to Aspergillus fumigatus Symptoms: Swelling over the left pectoral region Medication: Voriconazole Clinical Procedure: Pacemaker explantation Specialty: Cardiology Objective: Unusual clinical course Background: With the increasing use of cardiac implantable electronic devices (CIED), there has been an associated increase in rate of complications. Infection accounts for about 1% of these, of which only a handful were reported secondary to Aspergillus fumigatus. All of these were seen in chronically-ill patients with several co-morbid conditions within a few years of implantation. None have been reported in an otherwise immunocompetent patient at 7 years after CIED implantation. Case Report: A 67-year-old woman with symptomatic sick sinus syndrome required a pacemaker 15 years ago with subsequent revision 7 years prior due to battery depletion. She now presented with a left pectoral non-tender mass that developed over several weeks. She denied history of recent fever, trauma, or infection. An elective pacemaker revision and pocket exploration led to the drainage of 150 cc of serosanguineous discharge from the pocket. She received peri-procedural prophylaxis with Vancomycin, but later, wound cultures grew Aspergillus fumigatus. She underwent complete removal of the pacemaker system along with a 6-week course of voriconazole and is doing well. Conclusions: Even though Staphylococcus aureus causes most CIED infections, there should be a suspicion for fungal organisms, especially in culture-negative infections, in immunocompromised states like diabetes mellitus or with minimal improvement on antibiotics. If not treated appropriately, aspergillosis may have catastrophic outcomes, including endocarditis, often leading to death. Appropriate treatment should include immediate initiation of antifungals and removal of the CIED. It is still unclear why an immunocompetent patient developed aspergillosis, but appropriate management helped avoid a grave outcome. PMID:26250569

  16. Long-term clinical effects of ventricular pacing reduction with a changeover mode to minimize ventricular pacing in a general pacemaker population

    PubMed Central

    Stockburger, Martin; Boveda, Serge; Moreno, Javier; Da Costa, Antoine; Hatala, Robert; Brachmann, Johannes; Butter, Christian; Garcia Seara, Javier; Rolando, Mara; Defaye, Pascal

    2015-01-01

    Aim Right ventricular pacing (VP) has been hypothesized to increase the risk in heart failure (HF) and atrial fibrillation (AF). The ANSWER study evaluated, whether an AAI-DDD changeover mode to minimize VP (SafeR) improves outcome compared with DDD in a general dual-chamber pacemaker population. Methods and results ANSWER was a randomized controlled multicentre trial assessing SafeR vs. standard DDD in sinus node disease (SND) or AV block (AVB) patients. After a 1-month run-in period, they were randomized (1 : 1) and followed for 3 years. Pre-specified co-primary end-points were VP and the composite of hospitalization for HF, AF, or cardioversion. Pre-specified secondary end-points were cardiac death or HF hospitalizations and cardiovascular hospitalizations. ANSWER enrolled 650 patients (52.0% SND, 48% AVB) at 43 European centres and randomized in SafeR (n = 314) or DDD (n = 318). The SafeR mode showed a significant decrease in VP compared with DDD (11.5 vs. 93.6%, P < 0.0001 at 3 years). Deaths and syncope did not differ between randomization arms. No significant difference between groups [HR = 0.78; 95% CI (0.48–1.25); P = 0.30] was found in the time to event of the co-primary composite of hospitalization for HF, AF, or cardioversion, nor in the individual components. SafeR showed a 51% risk reduction (RR) in experiencing cardiac death or HF hospitalization [HR = 0.49; 95% CI (0.27–0.90); P = 0.02] and 30% RR in experiencing cardiovascular hospitalizations [HR = 0.70; 95% CI (0.49–1.00); P = 0.05]. Conclusion SafeR safely and significantly reduced VP in a general pacemaker population though had no effect on hospitalization for HF, AF, or cardioversion, when compared with DDD. PMID:25179761

  17. Transcription factor-driven conversion of quiescent cardiomyocytes to pacemaker cells

    PubMed Central

    Kapoor, Nidhi; Liang, Wenbin; Marbán, Eduardo; Cho, Hee Cheol

    2013-01-01

    The heartbeat originates within the sinoatrial node (SAN), a small highly-specialized structure containing <10,000 genuine pacemaker cells. The ~5 billion working cardiomyocytes downstream of the SAN remain quiescent when it fails, leading to circulatory collapse and fueling a $6B/year electronic pacemaker industry. To engineer faithful biological replicas of rare SAN cells as an alternative therapeutic strategy, we expressed a gene critical for early SAN specification in working cardiomyocytes in vitro, and in vivo in a model of bradycardia. Within days of transduction with Tbx18, ventricular cardiomyocytes in culture developed spontaneous electrical firing physiologically indistinguishable from that of SAN cells, along with morphological and epigenetic features characteristic of SAN cells. Focal Tbx18 gene transfer in the guinea-pig ventricle yielded ectopic pacemaker activity in vivo, correcting a bradycardic disease phenotype. Myocytes transduced in vivo acquired the cardinal tapering morphology and physiological automaticity of native SAN pacemaker cells, while controls remained rectangular and quiescent. The creation of induced SAN-like pacemaker (iSAN) cells by Tbx18 gene transfer opens new prospects for bioengineered pacemakers. PMID:23242162

  18. Irregular excitation patterns in reaction-diffusion systems due to perturbation by secondary pacemakers

    NASA Astrophysics Data System (ADS)

    Lenk, Claudia; Einax, Mario; Maass, Philipp

    2013-04-01

    Spatiotemporal excitation patterns in the FitzHugh-Nagumo model are studied, which result from the disturbance of a primary pacemaker by a secondary pacemaker. The primary and secondary pacemakers generate regular waves with frequencies fpace and fpert, respectively. The pacemakers are spatially separated, but waves emanating from them encounter each other via a small bridge. This leads to three different types I-III of irregular excitation patterns in disjunct domains of the fpace-fpert plane. Types I and II are caused by detachments of waves coming from the two pacemakers at corners of the bridge. Type III irregularities are confined to a boundary region of the system and originate from a partial penetration of the primary waves into a space, where circular wave fronts from the secondary pacemaker prevail. For this type, local frequencies can significantly exceed fpace and fpert. The degree of irregularity found for the three different types is quantified by the entropy of the local frequency distribution and an order parameter for phase coherence.

  19. 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 ?-adrenergic receptors (?-ARs) can induce a functional “brown-like” adipocyte phenotype. As cardiac natriuretic peptides (NPs) and ?-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 PPAR? coactivator-1? (PGC-1?) and UCP1 expression, induced mitochondriogenesis, and increased uncoupled and total respiration. At low concentrations, ANP and ?-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-1? 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

  20. Depression After a Cardiac Event or Diagnosis

    MedlinePLUS

    ... Fit-Friendly Worksites Program Requirements Fit-Friendly Resources Depression After A Cardiac Event or Diagnosis Updated:Jun 16,2014 Cardiovascular disease can trigger depression; counseling and medication can help beat it. When ...

  1. [Five-case report for transvenous epicardial pacemaker implantation via coronary sinus in patients after prosthetic tricuspid valve replacement].

    PubMed

    Xie, Qiying; Yang, Tianlun; Sun, Zelin; Pu, Xiaoqun; Li, Chuanchang; Yu, Zaixin; Yi, Jun; Deng, Jinhua; Meng, Shuangyuan

    2015-07-01

    Five patients after prosthetic tricuspid valve, who received pacemaker implantation via coronary sinus during Oct, 2011 and Jul, 2014, were enrolled. Pacemakers were implanted via coronary vein in 5 patients without complications. The stimulation thresholds keep stable and symptoms (such as short breath and fatigue) were disappeared during the follow-up. For patients after tricuspid valve replacement, implantation of pacemaker via coronary sinus provides a safe and invasive approach and avoids opening the chest again. PMID:26267699

  2. 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 growth, metabolism and food intake in adaptive ways that are responsive to an organism's internal and external conditions. Metabolic rate does not merely dictate growth rate, but is coadjusted with it. Energy and information use are intimately intertwined in living systems: biological signalling pathways both control and respond to the energetic state of an organism. This review also reveals that we have much to learn about the temporal structure of the pace of life. Are its component processes highly integrated and synchronized, or are they loosely connected and often discordant? And what causes the level of coordination that we see? These questions are of great theoretical and practical importance. PMID:24863680

  3. 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.

  4. CARDIAC MUSCLE

    PubMed Central

    Sommer, Joachim R.; Johnson, Edward A.

    1968-01-01

    With light and electron microscopy a comparison has been made of the morphology of ventricular (V) and Purkinje (P) fibers of the hearts of guinea pig, rabbit, cat, dog, goat, and sheep. The criteria, previously established for the rabbit heart, that V fibers are distinguished from P fibers by the respective presence and absence of transverse tubules is shown to be true for all animals studied. No evidence was found of a permanent connection between the sarcoplasmic reticulum and the extracellular space. The sarcoplasmic reticulum (SR) of V fibers formed couplings with the sarcolemma of a transverse tubule (interior coupling) and with the peripheral sarcolemma (peripheral coupling), whereas in P fibers the SR formed only peripheral couplings. The forms of the couplings were identical. The significance, with respect to excitation-contraction coupling, of the difference in the form of the couplings in cardiac versus skeletal muscle is discussed together with the electrophysiological implications of the differing geometries of bundles of P fibers from different animals. PMID:5645545

  5. Circadian pacemaker neurons change synaptic contacts across the day.

    PubMed

    Gorostiza, E Axel; Depetris-Chauvin, Ana; Frenkel, Lia; Pírez, Nicolás; Ceriani, María Fernanda

    2014-09-22

    Daily cycles of rest and activity are a common example of circadian control of physiology. In Drosophila, rhythmic locomotor cycles rely on the activity of 150-200 neurons grouped in seven clusters [1, 2]. Work from many laboratories points to the small ventral lateral neurons (sLNvs) as essential for circadian control of locomotor rhythmicity [3-7]. sLNv neurons undergo circadian remodeling of their axonal projections, opening the possibility for a circadian control of connectivity of these relevant circadian pacemakers [8]. Here we show that circadian plasticity of the sLNv axonal projections has further implications than mere structural changes. First, we found that the degree of daily structural plasticity exceeds that originally described [8], underscoring that changes in the degree of fasciculation as well as extension or pruning of axonal terminals could be involved. Interestingly, the quantity of active zones changes along the day, lending support to the attractive hypothesis that new synapses are formed while others are dismantled between late night and the following morning. More remarkably, taking full advantage of the GFP reconstitution across synaptic partners (GRASP) technique [9], we showed that, in addition to new synapses being added or removed, sLNv neurons contact different synaptic partners at different times along the day. These results lead us to propose that the circadian network, and in particular the sLNv neurons, orchestrates some of the physiological and behavioral differences between day and night by changing the path through which information travels. PMID:25155512

  6. Monocenter feasibility study of the MRI compatibility of the Evia pacemaker in combination with Safio S pacemaker lead

    PubMed Central

    2012-01-01

    Background The purpose of this study was to evaluate the feasibility of the magnetic resonance (MR) conditional pacemaker (PM) system (Evia SR-T and DR-T with Safio S leads) under MR conditions. Methods Patients with standard PM indications and Evia PM were eligible for enrollment in this single center prospective non-randomized pilot study. Patients underwent MR of the brain and lower lumbar spine at 1.5 Tesla. Atrial (RA) und ventricular (RV) lead parameters (sensing, pacing threshold [PTH], pacing impedance) were assessed immediately before (baseline follow-up [FU]) and immediately after MRI (1st FU), after 1 month (2nd FU) and 3 months (3rd FU). The effect of MR on serious adverse device effect (SADE) free-rate, on atrial and ventricular sensing (AS/VS; mV) and atrial (RA) and ventricular (RV) pacing thresholds (PTH; V/0.4 ms) were investigated between baseline and 2nd FU. Continuous variables are expressed as mean?±?SD and were compared using paired Student’s t-test. A p?pacemakers led to MR imaging artifacts on diffusion weighted sequences of the brain, but did not affect other sequences (e.g. FLAIR and T2 weighted spin-echo images). Conclusion The use of the MR conditional Evia PM in a MR environment under predefined conditions is feasible. No MR related SADEs nor clinically relevant changes in device functions occurred. PMID:23009683

  7. 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

  8. Managing pacemaker safety alerts: experience with three successive models of a single manufacturer.

    PubMed

    Gurevitz, Osnat; Granit, Chava; Bar-Lev, David; Luria, David; Lipchenca, Igor; Rotstein, Zeev; Eldar, Michael; Glikson, Michael

    2003-12-01

    This report describes the experience of a large pacemaker center during three successive replacement operations due to safety alerts involving three models from the same manufacturer. Between March 1993 and May 1999, 210 patients were implanted with three DDD pacemaker models (Sorin Biomedica, Saluggia, Italy) that were subsequently subject to safety alerts. Pacemaker records were reviewed for complications related to device malfunction, and those secondary to the replacement procedure. Pacemaker malfunction was observed in 16.4% of units despite much lower estimates from the company (range 1-4%). With the exception of one, all units were replaced. Malfunctions were discovered in 7 of 20 pacemakers following an urgent call for follow-up issued as a result of the alert. Twenty units implanted as substitutes for those replaced following the first alert turned out to be subject to the third alert. Significant clinical consequences of malfunction occurred in 5.3% of patients including a near fatal event in one case, while complications related to the replacement procedure occurred in 8.3% of patients, including one fatality. On the issuance of a safety alert, failure rates in a particular center may be higher than published by the manufacturer, and should prompt action by the center to weigh local incidence of device failure against complications of replacement procedures. When device failure mechanism is not entirely clear, particularly in cases of successive model failures, replacement devices from a different manufacturer should be considered. PMID:14675013

  9. Cardiac rehabilitation

    MedlinePLUS

    ... programs cover several different areas: Exercise. Regular exercise helps strengthen your heart and improve your overall health. During your sessions you may start with about a 5-minute warm-up followed by about 20 minutes of aerobics. The ...

  10. Searching for Non-Sense: Identification of Pacemaker Non-Sense and Non-Capture Failures using Machine Learning Techniques

    E-print Network

    Povinelli, Richard J.

    failures of the battery and electrodes, or physiological failures to respond to the stimulus may cause harmSearching for Non-Sense: Identification of Pacemaker Non-Sense and Non-Capture Failures using Abnormal or unexpected function of pacemakers due to mechanical failure of the implantation, electrical

  11. Cardiac conduction system

    MedlinePLUS Videos and Cool Tools

    ... cardiac muscle cells in the walls of the heart that send signals to the heart muscle causing it to contract. The main components ... the cardiac conduction system’s electrical activity in the heart.

  12. The end effector of circadian heart rate variation: the sinoatrial node pacemaker cell.

    PubMed

    Yaniv, Yael; Lakatta, Edward G

    2015-12-01

    Cardiovascular function is regulated by the rhythmicity of circadian, infradian and ultradian clocks. Specific time scales of different cell types drive their functions: circadian gene regulation at hours scale, activation-inactivation cycles of ion channels at millisecond scales, the heart's beating rate at hundreds of millisecond scales, and low frequency autonomic signaling at cycles of tens of seconds. Heart rate and rhythm are modulated by a hierarchical clock system: autonomic signaling from the brain releases neurotransmitters from the vagus and sympathetic nerves to the heart's pacemaker cells activate receptors on the cell. These receptors activating ultradian clock functions embedded within pacemaker cells include sarcoplasmic reticulum rhythmic spontaneous Ca2+ cycling, rhythmic ion channel current activation and inactivation, and rhythmic oscillatory mitochondria ATP production. Here we summarize the evidence that intrinsic pacemaker cell mechanisms are the end effector of the hierarchical brain-heart circadian clock system. [BMB Reports 2015; 48(12): 677-684]. PMID:25999176

  13. Cardiac tamponade: atypical presentations after cardiac surgery.

    PubMed

    Kirti, Ravi; Karadi, Rangaprasad

    2012-01-01

    We present two cases of cardiac tamponade presenting in the aftermath of cardiac surgery. We have briefly discussed the aetiology, presentation, diagnosis and management of the condition with emphasis on its atypical presentation in postoperative patients. A high index of suspicion and early access to echocardiography is necessary for prompt recognition and treatment of this life threatening emergency. PMID:22860267

  14. Reuse of explanted permanent pacemakers donated by funeral homes.

    PubMed

    Kantharia, Bharat K; Patel, Sandeep S; Kulkarni, Gaurav; Shah, Arti N; Lokhandwala, Yash; Mascarenhas, Erica; Mascarenhas, Daniel A N

    2012-01-15

    Poor patients in developing countries may not receive permanent pacemakers (PPMs) even as lifesaving measures because of their high cost. In this report we examined whether PPMs that were explanted and donated by funeral homes in the United States could be safely and effectively reused in indigent patients in India. With permission from the deceased patients' families, 121 PPMs were explanted and donated by funeral homes for reuse. These PPMs were sterilized and sent for implantation in needy and indigent patients at a charity hospital in Mumbai, India. From the pool of donated 121 PPMs, 53 (88%, 11 single-chamber PPMs, 21%, and 42 dual-chamber PPMs, 79%) were acceptable for reuse and implanted (37 new implants, 70%, and 16 for battery/generator replacement, 30%) in 53 patients (mean ± SD 64 ± 10 years old, 28 women, 53%). Indications for PPM implantation were complete heart block (n = 27, 51%) and sick sinus syndrome (n = 26, 49%). All patients were alive and well postoperatively. No significant complications including infections or device failures occurred over 19 to 1,827 days (mean 661) of follow-up. Of 40 patients (75%) who were followed locally, 4 (10%) died because of nonpacemaker-related causes; time to death was 121 to 750 days (mean 430) after PPM implantation. All except 2 patients (5%) reported marked improvement in their symptoms. There were only 4 patients (8%) who were previously employed, and all were able to resume their manual labor work. Also, of the women, 27 patients (96%) reported improvement in symptoms enabling them to resume regular household chores as housewives after PPM implantation. In conclusion, with proper device sterilization and handling protocols, reuse of explanted PPMs in poor patients in developing countries is safe and effective. Implantation of donated PPMs can not only save lives but also improve quality of life of needy poor patients. PMID:21996147

  15. Setups for in vitro assessment of RFID interference on pacemakers

    NASA Astrophysics Data System (ADS)

    Mattei, E.; Censi, F.; Delogu, A.; Ferrara, A.; Calcagnini, G.

    2013-08-01

    The aim of this study is to propose setups for in vitro assessment of RFID (radiofrequency identification) interference on pacemakers (PM). The voltage induced at the input stage of the PM by low-frequency (LF) and high-frequency (HF) RFID transmitters has been used to quantify the amount of the interference. A commercial PM was modified in order to measure the voltage at its input stage when exposed to a sinusoidal signal at 125 kHz and 13.56 MHz. At both frequencies, two antennas with different dimensions (diameter = 10 cm and 30 cm, respectively) were used to generate the interfering field, and the induced voltage was measured between the lead tip and the PM case (unipolar voltage), and between the tip and ring electrodes (bipolar voltage). The typical lead configurations adopted in similar studies or proposed by international standards, as well as lead paths closer to actual physiological implants were tested. At 125 kHz, the worst-case condition differs for the two antennas: the 10 cm antenna induced the highest voltage in the two-loop spiral configuration, whereas the 30 cm antenna in the 225 cm2 loop configuration. At 13.56 MHz, the highest voltage was observed for both the antennas in the 225 cm2 loop configuration. Bipolar voltages were found to be lower than the unipolar voltages induced in the same configurations, this difference being not as high as one could expect from theoretical considerations. The worst-case scenario, in terms of the induced voltage at the PM input stage, has been identified both for LF and HF readers, and for two sizes of transmitting antennas. These findings may provide the basis for the definition of a standard implant configuration and a lead path to test the EMI effects of LF and HF RFID transmitters on active implantable devices.

  16. Fetal Ventricular Hypertrabeculation/Noncompaction: Clinical Presentation, Genetics, Associated Cardiac and Extracardiac Abnormalities and Outcome.

    PubMed

    Stöllberger, Claudia; Wegner, Christian; Finsterer, Josef

    2015-10-01

    Left ventricular hypertrabeculation/noncompaction (LVHT) is a cardiac abnormality of unknown etiology. Aim of the review was to summarize the current knowledge about fetal LVHT, including clinical presentation, associated cardiac and extracardiac abnormalities and outcome. In 88 cases, LVHT was diagnosed by fetal echocardiography. In 36 %, no additional cardiac abnormalities were reported; in the remaining 64 %, one or more cardiac abnormalities were reported. Eight cases died prenatally, 17 were electively terminated, and 24 patients died after birth. Six patients were lost to follow-up, and 33 patients are alive at a mean age of 26 months. Surviving cases presented less frequently with fetal hydrops (13 vs. 62 %, p = 0.0004), complete heart block (27 vs. 78 %, p = 0.0076), more than three associated cardiac abnormalities (9 vs. 47 %, p = 0.0008) and more frequently with isolated LVHT (52 vs. 19 %, p = 0.009) than cases who died. Of the surviving patients, 16 received pharmacotherapy, three received pacemakers, eight underwent surgical procedures and four underwent heart transplantation. Postnatal regression of left ventricular hypertrophy and development of LVHT was found in four cases, improvement in cardiac function in two, and regression of right VHT in two. At autopsy, endocardial fibrosis was the most frequent abnormality in 92 %. Thirty-eight percentage of cases with fetal LVHT survived. Fetal and postnatal echocardiographic findings challenge the "embryonic pathogenetic" hypothesis of LVHT. Furthermore, fetal pathoanatomic findings like endocardial fibrosis might play a role in clarifying the still unsolved pathogenesis of LVHT. PMID:26008764

  17. Permanent Pacemaker-Induced Superior Vena Cava Syndrome: Successful Treatment by Endovascular Stent

    SciTech Connect

    Lanciego, Carlos Rodriguez, Mario; Rodriguez, Adela; Carbonell, Miguel A.; Garcia, Lorenzo Garcia

    2003-11-15

    The use of metallic stents in the management of benign and malignant superior vena cava syndrome (SVCS) is well documented. Symptomatic stenosis or occlusion of the SVC is a rare complication of a transvenous permanent pacemaker implant. Suggested treatments have included anticoagulation therapy, thrombolysis, balloon angioplasty and surgery. More recently, endovascular stenting has evolved as an attractive alternative but the data available in the literature are limited. We describe a case in which venous stenting with a Wallstent endoprosthesis was used successfully. The patient remains symptom free and with normal pacemaker function 36 months later.

  18. New evidence for coupled clock regulation of the normal automaticity of sinoatrial nodal pacemaker cells: bradycardic effects of ivabradine are linked to suppression of intracellular Ca²? cycling.

    PubMed

    Yaniv, Yael; Sirenko, Syevda; Ziman, Bruce D; Spurgeon, Harold A; Maltsev, Victor A; Lakatta, Edward G

    2013-09-01

    Beneficial clinical bradycardic effects of ivabradine (IVA) have been interpreted solely on the basis of If inhibition, because IVA specifically inhibits If in sinoatrial nodal pacemaker cells (SANC). However, it has been recently hypothesized that SANC normal automaticity is regulated by crosstalk between an "M clock," the ensemble of surface membrane ion channels, and a "Ca(2+) clock," the sarcoplasmic reticulum (SR). We tested the hypothesis that crosstalk between the two clocks regulates SANC automaticity, and that indirect suppression of the Ca(2+) clock further contributes to IVA-induced bradycardia. IVA (3 ?M) not only reduced If amplitude by 45 ± 6% in isolated rabbit SANC, but the IVA-induced slowing of the action potential (AP) firing rate was accompanied by reduced SR Ca(2+) load, slowed intracellular Ca(2+) cycling kinetics, and prolonged the period of spontaneous local Ca(2+) releases (LCRs) occurring during diastolic depolarization. Direct and specific inhibition of SERCA2 by cyclopiazonic acid (CPA) had effects similar to IVA on LCR period and AP cycle length. Specifically, the LCR period and AP cycle length shift toward longer times almost equally by either direct perturbations of the M clock (IVA) or the Ca(2+) clock (CPA), indicating that the LCR period reports the crosstalk between the clocks. Our numerical model simulations predict that entrainment between the two clocks that involves a reduction in INCX during diastolic depolarization is required to explain the experimentally AP firing rate reduction by IVA. In summary, our study provides new evidence that a coupled-clock system regulates normal cardiac pacemaker cell automaticity. Thus, IVA-induced bradycardia includes a suppression of both clocks within this system. PMID:23651631

  19. New evidence for coupled clock regulation of the normal automaticity of sinoatrial nodal pacemaker cells: bradycardic effects of ivabradine are linked to suppression of intracellular Ca2+ cycling

    PubMed Central

    Yaniv, Yael; Sirenko, Syevda; Ziman, Bruce D.; Spurgeon, Harold A.; Maltsev, Victor A.; Lakatta, Edward G.

    2013-01-01

    Beneficial clinical bradycardic effects of ivabradine (IVA) have been interpreted solely on the basis of If inhibition, because IVA specifically inhibits If in sinoatrial nodal pacemaker cells (SANC). However, it has been recently hypothesized that SANC normal automaticity is regulated by crosstalk between an “M clock,” the ensemble of surface membrane ion channels, and a “Ca2+ clock,” the sarcoplasmic reticulum (SR). We tested the hypothesis that crosstalk between the two clocks regulates SANC automaticity, and that indirect suppression of the Ca2+ clock further contributes to IVA-induced bradycardia. IVA (3?M) not only reduced If amplitude by 45±6% in isolated rabbit SANC, but the IVA-induced slowing of the action potential (AP) firing rate was accompanied by reduced SR Ca2+ load, slowed intracellular Ca2+ cycling kinetics, and prolonged the period of spontaneous local Ca2+ releases (LCRs) occurring during diastolic depolarization. Direct and specific inhibition of SERCA2 by cyclopiazonic acid (CPA) had effects similar to IVA on LCR period and AP cycle length. Specifically, the LCR period and AP cycle length shift toward longer times almost equally by either direct perturbations of the M clock (IVA) or the Ca2+ clock (CPA), indicating that the LCR period reports the crosstalk between the clocks. Our numerical model simulations predict that entrainment between the two clocks that involves a reduction in INCX during diastolic depolarization is required to explain the experimentally AP firing rate reduction by IVA. In summary, our study provides new evidence that a coupled-clock system regulates normal cardiac pacemaker cell automaticity. Thus, IVA-induced bradycardia includes a suppression of both clocks within this system. PMID:23651631

  20. Controlled Cardiac Computed Tomography

    PubMed Central

    Wang, Chenglin; Liu, Ying; Wang, Ge

    2006-01-01

    Cardiac computed tomography (CT) has been a hot topic for years because of the clinical importance of cardiac diseases and the rapid evolution of CT systems. In this paper, we propose a novel strategy for controlled cardiac CT that may effectively reduce image artifacts due to cardiac and respiratory motions. Our approach is radically different from existing ones and is based on controlling the X-ray source rotation velocity and powering status in reference to the cardiac motion. We theoretically show that by such a control-based intervention the data acquisition process can be optimized for cardiac CT in the cases of periodic and quasiperiodic cardiac motions. Specifically, we formulate the corresponding coordination/control schemes for either exact or approximate matches between the ideal and actual source positions, and report representative simulation results that support our analytic findings. PMID:23165017

  1. Cardiac gated ventilation

    SciTech Connect

    Hanson, C.W. III; Hoffman, E.A.

    1995-12-31

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart.

  2. Cardiac gated ventilation

    NASA Astrophysics Data System (ADS)

    Hanson, C. William, III; Hoffman, Eric A.

    1995-05-01

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. We evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50msec scan aperture. Multislice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. We observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a nonfailing model of the heart.

  3. Electrogenic sodium extrusion in cardiac Purkinje fibers

    PubMed Central

    1979-01-01

    Thin canine cardiac Purkinje fibers in a fast flow chamber were exposed to K-free fluid for 15 s to 6 min to initiate "sodium loading," then returned to K-containing fluid to stimulate the sodium pump. The electrophysiological effects of enhanced pump activity may result from extracellular K depletion caused by enhanced cellular uptake of K or from an increase in the current generated as a result of unequal pumped movements of Na and K, or from both. The effects of pump stimulation were therefore studied under three conditions in which lowering the external K concentration ([K]0) causes changes opposite to those expected from an increase in pump current. First, the resting potential of Purkinje fibers may have either a "high" value of a "low" (less negative) value: at the low level of potential, experimental reduction of [K]0 causes depolarization, whereas an increase in pump current should cause hyperpolarization. Second, in regularly stimulated Purkinje fibers, lowering [K]0 prolongs the action potential, whereas an increase in outward pump current should shorten it. Finally, lowering [K]0 enhances spontaneous "pacemaker" activity in Purkinje fibers, whereas an increase in outward pump current should reduce or abolish spontaneous activity. Under all three conditions, we find that the effects of temporary stimulation of the sodium pump are those expected from a transient increase in outward pump current, not those expected from K depletion. PMID:479817

  4. Modes of induced cardiac arrest: hyperkalemia and hypocalcemia - Literature review

    PubMed Central

    de Oliveira, Marcos Aurélio Barboza; Brandi, Antônio Carlos; dos Santos, Carlos Alberto; Botelho, Paulo Henrique Husseini; Cortez, José Luis Lasso; Braile, Domingo Marcolino

    2014-01-01

    The entry of sodium and calcium play a key effect on myocyte subjected to cardiac arrest by hyperkalemia. They cause cell swelling, acidosis, consumption of adenosine triphosphate and trigger programmed cell death. Cardiac arrest caused by hypocalcemia maintains intracellular adenosine triphosphate levels, improves diastolic performance and reduces oxygen consumption, which can be translated into better protection to myocyte injury induced by cardiac arrest. PMID:25372919

  5. Safety of Electromagnetic Articulography in Patients with Pacemakers and Implantable Cardioverter-Defibrillators

    ERIC Educational Resources Information Center

    Joglar, Jose A.; Nguyen, Carol; Garst, Diane M.; Katz, William F.

    2009-01-01

    Purpose: "Electromagnetic articulography (EMA)" uses a helmet to create alternating magnetic fields for tracking speech articulator movement. An important safety consideration is whether EMA magnetic fields interfere with the operation of speakers' pacemakers or implantable cardioverter-defibrillators (ICDs). In this investigation, individuals…

  6. Influence of Continuous Nursing on the Psychological State and Coping Style of Patients Undergoing Pacemaker Implantation

    PubMed Central

    LIU, Xin; HE, Xu; LI, Ling; HUANG, Lili; LIU, Zhaojun

    2015-01-01

    Background: Patients undergoing pacemaker implantation often experience anxiety and fear. As such, studies have focused on the mechanisms that relieve the negative emotions caused by the intervention. Continuous nursing is a safe and effective nursing mode. In this study, continuous nursing intervention was provided for elderly patients undergoing pacemaker implantation and an empirical investigation was performed to determine the effects of their negative emotion and disease-coping ability. Methods: Overall, 114 (68 males and 46 females) elderly patients who were undergoing pacemaker implantation from Harbin City (China), were enrolled in the study. The patients were divided into two groups, namely, the control group and the intervention group, based on different nursing methods. Routine nursing was applied to the control group; continuous nursing support was provided for the intervention group from January 2014 to January 2015. The nursing results of the two groups were compared. These results were also evaluated using self-rating depression scale, self-rating anxiety scale, and trait coping style questionnaire. Result: The effects of depression and anxiety intervention were significant in the intervention group (P<0.05). Compared with the control group, the intervention group did not significantly differ. The coping style of the intervention group elicited significant effects. Compared with the control group, the intervention group was significantly different (P < 0.05). Conclusion: Continuous nursing can relieve the negative emotion and improve the negative coping style of patients undergoing pacemaker implantation. PMID:26576373

  7. 76 FR 64223 - Cardiovascular Devices; Reclassification of External Pacemaker Pulse Generator Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-17

    ... rule (44 FR 13284, March 9, 1979 and 44 FR 13372, March 9, 1979), the Cardiovascular Devices Panel... premarket approval for external pacemaker pulse generator devices (52 FR 17732, May 11, 1987). In 2009, FDA..., 2009 (74 FR 16214, April 9, 2009). In response to that order, FDA received reclassification...

  8. CaV3.1 is a tremor rhythm pacemaker in the inferior olive

    E-print Network

    Kim, Daesoo

    CaV3.1 is a tremor rhythm pacemaker in the inferior olive Young-Gyun Parka,1 , Hye-Yeon Parka,1 , C+ channels in the inferior olive contributes to the onset of the tremor in a pharmacological model that the CaV3.1-deficient inferior olive neurons lacked the subthreshold os- cillation of membrane potentials

  9. 21 CFR 870.3680 - Cardiovascular permanent or temporary pacemaker electrode.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... applied to the heart. The device is used to transmit a pacing electrical stimulus from the pulse generator to the heart and/or to transmit the electrical signal of the heart to the pulse generator. (2... end connected to an implantable pacemaker pulse generator and the other end applied to the heart....

  10. 21 CFR 870.3680 - Cardiovascular permanent or temporary pacemaker electrode.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... applied to the heart. The device is used to transmit a pacing electrical stimulus from the pulse generator to the heart and/or to transmit the electrical signal of the heart to the pulse generator. (2... end connected to an implantable pacemaker pulse generator and the other end applied to the heart....

  11. 21 CFR 870.3680 - Cardiovascular permanent or temporary pacemaker electrode.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... applied to the heart. The device is used to transmit a pacing electrical stimulus from the pulse generator to the heart and/or to transmit the electrical signal of the heart to the pulse generator. (2... end connected to an implantable pacemaker pulse generator and the other end applied to the heart....

  12. 21 CFR 870.3680 - Cardiovascular permanent or temporary pacemaker electrode.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... applied to the heart. The device is used to transmit a pacing electrical stimulus from the pulse generator to the heart and/or to transmit the electrical signal of the heart to the pulse generator. (2... end connected to an implantable pacemaker pulse generator and the other end applied to the heart....

  13. 21 CFR 870.3680 - Cardiovascular permanent or temporary pacemaker electrode.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... applied to the heart. The device is used to transmit a pacing electrical stimulus from the pulse generator to the heart and/or to transmit the electrical signal of the heart to the pulse generator. (2... end connected to an implantable pacemaker pulse generator and the other end applied to the heart....

  14. Decreased human circadian pacemaker influence after 100 days in space: a case study

    NASA Technical Reports Server (NTRS)

    Monk, T. H.; Kennedy, K. S.; Rose, L. R.; Linenger, J. M.

    2001-01-01

    OBJECTIVE: The objectives of this study were (1) to assess the circadian rhythms and sleep of a healthy, 42-year-old male astronaut experiencing microgravity (weightlessness) for nearly 5 months while living aboard Space Station Mir as it orbited Earth and (2) to determine the effects of prolonged space flight on the endogenous circadian pacemaker, as indicated by oral temperature and subjective alertness rhythms, and their ramifications for sleep, alertness, and performance. METHODS: For three 12- to 14-day blocks of time (spread throughout the mission), oral temperatures were taken and subjective alertness was self-rated five times per day. Sleep diaries and performance tests were also completed daily during each block. RESULTS: Examination of the subject's circadian alertness and oral temperature rhythms suggested that the endogenous circadian pacemaker seemed to function quite well up to 90 days in space. Thereafter (on days 110-122), the influence of the endogenous circadian pacemaker on oral temperature and subjective alertness circadian rhythms was considerably weakened, with consequent disruptions in sleep. CONCLUSIONS: Space missions lasting more than 3 months might result in diminished circadian pacemaker influence in astronauts, leading to eventual sleep problems.

  15. Measuring contraction propagation and localizing pacemaker cells using high speed video microscopy

    NASA Astrophysics Data System (ADS)

    Akl, Tony J.; Nepiyushchikh, Zhanna V.; Gashev, Anatoliy A.; Zawieja, David C.; Coté, Gerard L.

    2011-02-01

    Previous studies have shown the ability of many lymphatic vessels to contract phasically to pump lymph. Every lymphangion can act like a heart with pacemaker sites that initiate the phasic contractions. The contractile wave propagates along the vessel to synchronize the contraction. However, determining the location of the pacemaker sites within these vessels has proven to be very difficult. A high speed video microscopy system with an automated algorithm to detect pacemaker location and calculate the propagation velocity, speed, duration, and frequency of the contractions is presented in this paper. Previous methods for determining the contractile wave propagation velocity manually were time consuming and subject to errors and potential bias. The presented algorithm is semiautomated giving objective results based on predefined criteria with the option of user intervention. The system was first tested on simulation images and then on images acquired from isolated microlymphatic mesenteric vessels. We recorded contraction propagation velocities around 10 mm/s with a shortening speed of 20.4 to 27.1 ?m/s on average and a contraction frequency of 7.4 to 21.6 contractions/min. The simulation results showed that the algorithm has no systematic error when compared to manual tracking. The system was used to determine the pacemaker location with a precision of 28 ?m when using a frame rate of 300 frames per second.

  16. Transcription factor ISL1 is essential for pacemaker development and function

    PubMed Central

    Liang, Xingqun; Zhang, Qingquan; Cattaneo, Paola; Zhuang, Shaowei; Gong, Xiaohui; Spann, Nathanael J.; Jiang, Cizhong; Cao, Xinkai; Zhao, Xiaodong; Zhang, Xiaoli; Bu, Lei; Wang, Gang; Chen, H.S. Vincent; Zhuang, Tao; Yan, Jie; Geng, Peng; Luo, Lina; Banerjee, Indroneal; Chen, Yihan; Glass, Christopher K.; Zambon, Alexander C.; Chen, Ju; Sun, Yunfu; Evans, Sylvia M.

    2015-01-01

    The sinoatrial node (SAN) maintains a rhythmic heartbeat; therefore, a better understanding of factors that drive SAN development and function is crucial to generation of potential therapies, such as biological pacemakers, for sinus arrhythmias. Here, we determined that the LIM homeodomain transcription factor ISL1 plays a key role in survival, proliferation, and function of pacemaker cells throughout development. Analysis of several Isl1 mutant mouse lines, including animals harboring an SAN-specific Isl1 deletion, revealed that ISL1 within SAN is a requirement for early embryonic viability. RNA-sequencing (RNA-seq) analyses of FACS-purified cells from ISL1-deficient SANs revealed that a number of genes critical for SAN function, including those encoding transcription factors and ion channels, were downstream of ISL1. Chromatin immunoprecipitation assays performed with anti-ISL1 antibodies and chromatin extracts from FACS-purified SAN cells demonstrated that ISL1 directly binds genomic regions within several genes required for normal pacemaker function, including subunits of the L-type calcium channel, Ank2, and Tbx3. Other genes implicated in abnormal heart rhythm in humans were also direct ISL1 targets. Together, our results demonstrate that ISL1 regulates approximately one-third of SAN-specific genes, indicate that a combination of ISL1 and other SAN transcription factors could be utilized to generate pacemaker cells, and suggest ISL1 mutations may underlie sick sinus syndrome. PMID:26193633

  17. 77 FR 39924 - Effective Date of Requirement for Premarket Approval for Cardiovascular Permanent Pacemaker...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-06

    ...The Food and Drug Administration (FDA) is issuing a final rule to require the filing of a premarket approval application (PMA) or a notice of completion of a product development protocol (PDP) for the cardiovascular permanent pacemaker electrode. The Agency has summarized its findings regarding the degree of risk of illness or injury designed to be eliminated or reduced by requiring the device......

  18. The 11th world survey of cardiac pacing and implantable cardioverter-defibrillators: calendar year 2009--a World Society of Arrhythmia's project.

    PubMed

    Mond, Harry G; Proclemer, Alessandro

    2011-08-01

    A worldwide cardiac pacing and implantable cardioverter-defibrillator (ICD) survey was undertaken for calendar year 2009 and compared to a similar survey conducted in 2005. There were contributions from 61 countries: 25 from Europe, 20 from the Asia Pacific region, seven from the Middle East and Africa, and nine from the Americas. The 2009 survey involved 1,002,664 pacemakers, with 737,840 new implants and 264,824 replacements. The United States of America (USA) had the largest number of cardiac pacemaker implants (225,567) and Germany the highest new implants per million population (927). Virtually all countries showed increases in implant numbers over the 4 years between surveys. High-degree atrioventricular block and sick sinus syndrome remain the major indications for implantation of a cardiac pacemaker. There remains a high percentage of VVI(R) pacing in the developing countries, although compared to the 2005 survey, virtually all countries had increased the percentage of DDDR implants. Pacing leads were predominantly transvenous, bipolar, and active fixation. The survey also involved 328,027 ICDs, with 222,407 new implants and 105,620 replacements. Virtually all countries surveyed showed a significant rise in the use of ICDs with the largest implanter being the USA (133,262) with 434 new implants per million population. This was the largest pacing and ICD survey ever performed, because of mainly a group of loyal enthusiastic survey coordinators. It encompasses more than 80% of all the pacemakers and ICDs implanted worldwide during 2009. PMID:21707667

  19. Cardiac Coordination and Mechanics 1 CARDIAC ELECTROPHYSIOLOGY*

    E-print Network

    Prestwich, Ken

    of the sympathetic nervous system. We will also see how to found cardiac output using A. The purpose of the heart's electrical system is to initiate muscle cells and does not come from the nervous system. Likewise, we can

  20. Survival after prolonged resuscitation with 99 defibrillations due to Torsade De Pointes cardiac electrical storm: a case report.

    PubMed

    Nakstad, Anders Rostrup; Eek, Christian; Aarhus, Dag; Larsen, Anne; Haugaa, Kristina Hermann

    2010-01-01

    A 48-year-old previously healthy woman suffered witnessed cardiac arrest in hospital. She achieved return of spontaneous circulation and was transferred to the intensive care unit. During the following 3 hours, she suffered a cardiac electrical storm with 98 episodes of Torsade de Pointes ventricular tachycardia rapidly degenerating to ventricular fibrillation. She was converted with a total of 99 defibrillations. There was no response to the use of any recommended anti arrhythmic drugs. However, the use of bretylium surprisingly stabilized her heart rhythm and facilitated placing of a temporary pacemaker. Overdrive pacing prevented further arrhythmias and was life saving. A number of beneficial factors may have contributed to the good neurological outcome. Further investigations gave no explanation for her cardiac electrical storm. PMID:20137096

  1. Stimulating endogenous cardiac repair

    PubMed Central

    Finan, Amanda; Richard, Sylvain

    2015-01-01

    The healthy adult heart has a low turnover of cardiac myocytes. The renewal capacity, however, is augmented after cardiac injury. Participants in cardiac regeneration include cardiac myocytes themselves, cardiac progenitor cells, and peripheral stem cells, particularly from the bone marrow compartment. Cardiac progenitor cells and bone marrow stem cells are augmented after cardiac injury, migrate to the myocardium, and support regeneration. Depletion studies of these populations have demonstrated their necessary role in cardiac repair. However, the potential of these cells to completely regenerate the heart is limited. Efforts are now being focused on ways to augment these natural pathways to improve cardiac healing, primarily after ischemic injury but in other cardiac pathologies as well. Cell and gene therapy or pharmacological interventions are proposed mechanisms. Cell therapy has demonstrated modest results and has passed into clinical trials. However, the beneficial effects of cell therapy have primarily been their ability to produce paracrine effects on the cardiac tissue and recruit endogenous stem cell populations as opposed to direct cardiac regeneration. Gene therapy efforts have focused on prolonging or reactivating natural signaling pathways. Positive results have been demonstrated to activate the endogenous stem cell populations and are currently being tested in clinical trials. A potential new avenue may be to refine pharmacological treatments that are currently in place in the clinic. Evidence is mounting that drugs such as statins or beta blockers may alter endogenous stem cell activity. Understanding the effects of these drugs on stem cell repair while keeping in mind their primary function may strike a balance in myocardial healing. To maximize endogenous cardiac regeneration, a combination of these approaches could ameliorate the overall repair process to incorporate the participation of multiple cellular players. PMID:26484341

  2. Measuring cardiac waste: the premier cardiac waste measures.

    PubMed

    Lowe, Timothy J; Partovian, Chohreh; Kroch, Eugene; Martin, John; Bankowitz, Richard

    2014-01-01

    The authors developed 8 measures of waste associated with cardiac procedures to assist hospitals in comparing their performance with peer facilities. Measure selection was based on review of the research literature, clinical guidelines, and consultation with key stakeholders. Development and validation used the data from 261 hospitals in a split-sample design. Measures were risk adjusted using Premier's CareScience methodologies or mean peer value based on Medicare Severity Diagnosis-Related Group assignment. High variability was found in resource utilization across facilities. Validation of the measures using item-to-total correlations (range = 0.27-0.78), Cronbach ? (.88), and Spearman rank correlation (0.92) showed high reliability and discriminatory power. Because of the level of variability observed among hospitals, this study suggests that there is opportunity for facilities to design successful waste reduction programs targeting cardiac-device procedures. PMID:23719033

  3. Extracting versus abandoning sterile pacemaker and defibrillator leads.

    PubMed

    Rijal, Shasank; Shah, Rashmee U; Saba, Samir

    2015-04-15

    Nonfunctional or recalled cardiac implantable electronic device leads can be revised with either lead extraction (LE) or lead capping (LC). Factors that influence this decision and comparative outcomes of these strategies are unclear. We reviewed data from our institution to identify patients who received LE (n = 296) or LC (n = 192) from 2006 to 2012. Patients with infectious indications for lead removal were excluded. We compared unanticipated device-related procedures, defined as cardiac implantable electronic device procedures not for device upgrade or battery depletion, using a proportional hazards model adjusted for differences in baseline characteristics. Secondary outcomes were procedural complications, hospitalizations, and all-cause mortality. Patients who received LE were younger and more likely to have an operator with extraction experience (76% vs 26%, p <0.001). Leads removed by experienced extractors versus nonextractors had longer dwell times (4.2 ± 3.6 vs 0.9 ± 1.1 years, p <0.001). Over a median follow-up of 3.0 (interquartile range = 3.2) years, the adjusted risk of unanticipated device-related procedures was similar for LE versus LC (hazard ratio 1.04, 95% confidence interval 0.62 to 1.75). Complications, hospitalization rates, and mortality rates were also similar between the 2 groups. In conclusion, lead revision strategy is influenced by operator extraction experience and dwell time of leads. In our analysis, we found no difference in outcomes between the 2 strategies. PMID:25697918

  4. Cardiac innervation and sudden cardiac death.

    PubMed

    Fukuda, Keiichi; Kanazawa, Hideaki; Aizawa, Yoshiyasu; Ardell, Jeffrey L; Shivkumar, Kalyanam

    2015-06-01

    Afferent and efferent cardiac neurotransmission via the cardiac nerves intricately modulates nearly all physiological functions of the heart (chronotropy, dromotropy, lusitropy, and inotropy). Afferent information from the heart is transmitted to higher levels of the nervous system for processing (intrinsic cardiac nervous system, extracardiac-intrathoracic ganglia, spinal cord, brain stem, and higher centers), which ultimately results in efferent cardiomotor neural impulses (via the sympathetic and parasympathetic nerves). This system forms interacting feedback loops that provide physiological stability for maintaining normal rhythm and life-sustaining circulation. This system also ensures that there is fine-tuned regulation of sympathetic-parasympathetic balance in the heart under normal and stressed states in the short (beat to beat), intermediate (minutes to hours), and long term (days to years). This important neurovisceral/autonomic nervous system also plays a major role in the pathophysiology and progression of heart disease, including heart failure and arrhythmias leading to sudden cardiac death. Transdifferentiation of neurons in heart failure, functional denervation, cardiac and extracardiac neural remodeling has also been identified and characterized during the progression of disease. Recent advances in understanding the cellular and molecular processes governing innervation and the functional control of the myocardium in health and disease provide a rational mechanistic basis for the development of neuraxial therapies for preventing sudden cardiac death and other arrhythmias. Advances in cellular, molecular, and bioengineering realms have underscored the emergence of this area as an important avenue of scientific inquiry and therapeutic intervention. PMID:26044253

  5. Improving e-discharge letters for Permanent pacemaker insertions at Wansbeck General Hospital

    PubMed Central

    Taylor, Christopher

    2013-01-01

    670 patients attend Wansbeck General Hospital each year for elective and emergency permanent pacemaker insertion or modification. Elective patients for new devices attend the cardiology department on the day of procedure and are clerked onto the cardiology ward after insertion. Patients are discharged home the following day with a letter typed by a junior doctor. Prior to October 2011, junior doctors were unaware of any guidelines regarding content of discharge letters due to poor accessibility. Vital information such as pacemaker model and indication for implantation were frequently absent from the typed summaries. In October 2011, the cardiology department reviewed the guidelines establishing the information required in all discharge summaries for pacemaker implantation and these guidelines were published on the ward in an easy to follow proforma for any junior doctor typing letters. Eight essential criteria should be included in each letter; date and indication for insertion, pacemaker type, make and model, access route, complications, chest x-ray and device check results, and follow-up details. Finally, a copy of the letter was to be sent to the cardiology department for clinic follow-up. Ten letters were audited prior to the proforma being issued. 0 letters contained 100% of the required information. Main criteria missing in most letters included indication for insertion (50%), make of device (0%), the route of access (10%) and cc to cardiology department (0%). 70 letters were audited in October 2012, one year following introduction of the discharge proforma.100% of letters contained all of the eight essential criteria required by the departmental guidelines. 53% of the letters were also received by the cardiology department. In conclusion, a set of easy to follow guidelines in the form of a published document on the cardiology ward has produced dramatic improvement in the quality of e-discharge letters for patients undergoing permanent pacemaker implantation.

  6. Tachybradycardia in the isolated canine right atrium induced by chronic sympathetic stimulation and pacemaker current inhibition.

    PubMed

    Joung, Boyoung; Shinohara, Tetsuji; Zhang, Hong; Kim, Daehyeok; Choi, Eue-Keun; On, Yong-Keun; Piccirillo, Gianfranco; Chen, Peng-Sheng; Lin, Shien-Fong

    2010-09-01

    The mechanisms of sinoatrial node (SAN) dysfunction in patients with chronically elevated sympathetic tone and reduced pacemaker current (I(f); such as heart failure) are poorly understood. We simultaneously mapped membrane potential and intracellular Ca(2+) in the Langendorff-perfused canine right atrium (RA). Blockade of either I(f) (ZD-7288) or sarcoplasmic reticulum Ca(2+) release (ryanodine) alone decreased heart rate by 8% (n = 3) and 16% (n = 3), respectively. Combined treatment of ZD-7288 and ryanodine consistently resulted in prolonged (> or =3 s) sinus pauses (PSPs) (n = 4). However, the middle SAN remained as the leading pacemaking site after these treatments. Prolonged exposure with isoproterenol (0.01 micromol/l) followed by ZD-7288 completely suppressed SAN but triggered recurrent ectopic atrial tachycardia. Cessation of tachycardia was followed by PSPs in five of eight RAs. Isoproterenol initially increased heart rate by 75% from baseline with late diastolic intracellular Ca(2+) elevation (LDCAE) from the superior SAN. However, after a prolonged isoproterenol infusion, LDCAE disappeared in the superior SAN, the leading pacemaker shifted to the inferior SAN, and the rate reduced to 52% above baseline. Caffeine (2 ml, 20 mmol/l) injection after a prolonged isoproterenol infusion produced LDCAE in the SAN and accelerated the SAN rate, ruling out sarcoplasmic reticulum Ca(2+) depletion as a cause of Ca(2+) clock malfunction. We conclude that in an isolated canine RA preparation, chronically elevated sympathetic tone results in abnormal pacemaking hierarchy in the RA, including suppression of the superior SAN and enhanced pacemaking from ectopic sites. Combined malfunction of both membrane and Ca(2+) clocks underlies the mechanisms of PSPs. PMID:20601460

  7. 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. PMID:25908772

  8. [Complete atrioventricular block due to cardiac metastasis from bladder cancer: case report].

    PubMed

    Ueda, Norichika; Kawamura, Masataka; Nakazawa, Shigeaki; Hirai, Toshiaki; Kishikawa, Hidefumi; Nishimura, Kenji; Morimoto, Keisuke

    2014-10-01

    A 72-year-old woman was diagnosed with bladder cancer (cT3bN0M0). After 2 cycles of GC (gemcitabine?cisplatin) neoadjuvant chemotherapy, the patient underwent a cystectomy and ileal conduit construction. Pathological findings showed urothelial carcinoma, high grade, G2?G3, pT3a, INF?, ly0, v1. Six months after the operation, metastases to the liver, lung, left adrenal gland, rib, multiple lymph nodes, and peritoneum were revealed. Under palliative care, she suffered from palpitation and general fatigue. Electrocardiogram findings showed a complete atrioventricular block, while echocardiography and computed tomography revealed cardiac metastasis. We diagnosed her with complete atrioventricular block due to cardiac metastasis from bladder cancer. She died 7 days after onset of the complete atrioventricular block without use of a pacemaker. PMID:25391782

  9. Aortic perforation due to cardiac resynchronisation therapy defibrillator lead placement: Case report and medicolegal considerations

    PubMed Central

    Grande, Antonino M.; Fiore, Antonio; Merlano, Maurizio; Buzzi, Fabio; Mazzola, Alessandro

    2015-01-01

    A 45-year-old woman with dilated cardiomyopathy was admitted for the upgrade of a previously implanted pacemaker. Echocardiography showed intraventricular dyssynchrony and a low ejection fraction (0.35). Treatment with a cardiac resynchronization therapy defibrillator (CRT-D) was selected and the device was implanted. CRT-D interrogation revealed proper function. Following procedure termination, the patient went into cardiac arrest and died despite resuscitation attempts. An autopsy revealed that the medial aspect of the right atrium was pierced by an active lead and that the aorta had a deep lesion, 2 mm in length, on its lateral aspect. We explain the probable pathogenesis of this patient?s death. PMID:26702323

  10. Cardiac rehabilitation in the elderly.

    PubMed

    Menezes, Arthur R; Lavie, Carl J; Forman, Daniel E; Arena, Ross; Milani, Richard V; Franklin, Barry A

    2014-01-01

    Coronary heart disease (CHD) is the leading cause of death worldwide. Advanced age is associated with a higher prevalence of CHD as well as increased morbidity and mortality. One key vulnerability relates to the fact that older individuals are generally among the least fit, least active cohort and at increased risk of complications after an acute cardiac event and/or major surgery. There is ample evidence to demonstrate the beneficial effects of exercised-based cardiac rehabilitation (CR) programs on improving functional capacity and other indices of cardiovascular (CV) health. Although the predominant number of studies is in middle-aged patients, there is an escalating amount of new information that establishes the cardioprotective role of CR and, in particular, structured exercise therapy (ET) among the elderly. The present review summarizes the current data available regarding CR and ET and its salutary impact on today's growing population of older adults with CHD. PMID:25216614

  11. Teaching Cardiac Electrophysiology Modeling to Undergraduate Students: Laboratory Exercises and GPU Programming for the Study of Arrhythmias and Spiral Wave Dynamics

    ERIC Educational Resources Information Center

    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., Jr.; Grosu, Radu; Glimm, James; Smolka, Scott A.; Cherry, Elizabeth M.; Clarke, Edmund M.; Griffeth, Nancy; Fenton, Flavio H.

    2011-01-01

    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 collaborated on a study aimed at characterizing the voltage dynamics and arrhythmogenic behavior of cardiac cells for a broad range of physiologically relevant conditions…

  12. Cardiac developmental toxicity

    PubMed Central

    Mahler, Gretchen J.; Butcher, Jonathan T.

    2013-01-01

    Congenital heart disease is a highly prevalent problem with mostly unknown origins. Many cases of CHD likely involve an environmental exposure coupled with genetic susceptibility, but practical and ethical considerations make nongenetic causes of CHD difficult to assess in humans. The development of the heart is highly conserved across all vertebrate species, making animal models an excellent option for screening potential cardiac teratogens. This review will discuss exposures known to cause cardiac defects, stages of heart development that are most sensitive to teratogen exposure, benefits and limitations of animal models of cardiac development, and future considerations for cardiac developmental toxicity research. PMID:22271678

  13. [Cardiac involvement in polymyositis].

    PubMed

    Romdhane, M B; Mahdhaoui, A; Khelifa, M B; Lagren, A; Hajri, S E; Bouraoui, H; Trimeche, B; Ghannouchi, N; Jeridi, G; Bahri, F

    2012-08-01

    Cardiovascular involvement in polymyositis constitutes a major cause of death. However, the cardiac location is rarely symptomatic and does not usually represent the principle clinical feature at the time of the initial presentation. We present here an unusual case of polymyositis with severe and polymorph cardiac disturbances that predominant the muscular signs. PMID:20709312

  14. Real-time relationship between PKA biochemical signal network dynamics and increased action potential firing rate in heart pacemaker cells: Kinetics of PKA activation in heart pacemaker cells.

    PubMed

    Yaniv, Yael; Ganesan, Ambhighainath; Yang, Dongmei; Ziman, Bruce D; Lyashkov, Alexey E; Levchenko, Andre; Zhang, Jin; Lakatta, Edward G

    2015-09-01

    cAMP-PKA protein kinase is a key nodal signaling pathway that regulates a wide range of heart pacemaker cell functions. These functions are predicted to be involved in regulation of spontaneous action potential (AP) generation of these cells. Here we investigate if the kinetics and stoichiometry of increase in PKA activity match the increase in AP firing rate in response to ?-adrenergic receptor (?-AR) stimulation or phosphodiesterase (PDE) inhibition, that alters the AP firing rate of heart sinoatrial pacemaker cells. In cultured adult rabbit pacemaker cells infected with an adenovirus expressing the FRET sensor AKAR3, the EC50 in response to graded increases in the intensity of ?-AR stimulation (by Isoproterenol) the magnitude of the increases in PKA activity and the spontaneous AP firing rate were similar (0.4±0.1nM vs. 0.6±0.15nM, respectively). Moreover, the kinetics (t1/2) of the increases in PKA activity and spontaneous AP firing rate in response to ?-AR stimulation or PDE inhibition were tightly linked. We characterized the system rate-limiting biochemical reactions by integrating these experimentally derived data into a mechanistic-computational model. Model simulations predicted that phospholamban phosphorylation is a potent target of the increase in PKA activity that links to increase in spontaneous AP firing rate. In summary, the kinetics and stoichiometry of increases in PKA activity in response to a physiological (?-AR stimulation) or pharmacological (PDE inhibitor) stimuli match those of changes in the AP firing rate. Thus Ca(2+)-cAMP/PKA-dependent phosphorylation limits the rate and magnitude of increase in spontaneous AP firing rate. PMID:26241846

  15. Functional cardiac tissue engineering

    PubMed Central

    Liau, Brian; Zhang, Donghui; Bursac, Nenad

    2013-01-01

    Heart attack remains the leading cause of death in both men and women worldwide. Stem cell-based therapies, including the use of engineered cardiac tissues, have the potential to treat the massive cell loss and pathological remodeling resulting from heart attack. Specifically, embryonic and induced pluripotent stem cells are a promising source for generation of therapeutically relevant numbers of functional cardiomyocytes and engineering of cardiac tissues in vitro. This review will describe methodologies for successful differentiation of pluripotent stem cells towards the cardiovascular cell lineages as they pertain to the field of cardiac tissue engineering. The emphasis will be placed on comparing the functional maturation in engineered cardiac tissues and developing heart and on methods to quantify cardiac electrical and mechanical function at different spatial scales. PMID:22397609

  16. Maternal Cardiac Arrest: A Practical and Comprehensive Review

    PubMed Central

    Jeejeebhoy, Farida M.; Morrison, Laurie J.

    2013-01-01

    Cardiac arrest during pregnancy is a dedicated chapter in the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care; however, a robust maternal cardiac arrest knowledge translation strategy and emergency response plan is not usually the focus of institutional emergency preparedness programs. Although maternal cardiac arrest is rare, the emergency department is a high-risk area for receiving pregnant women in either prearrest or full cardiac arrest. It is imperative that institutions review and update emergency response plans for a maternal arrest. This review highlights the most recent science, guidelines, and recommended implementation strategies related to a maternal arrest. The aim of this paper is to increase the understanding of the important physiological differences of, and management strategies for, a maternal cardiac arrest, as well as provide institutions with the most up-to-date literature on which they can build emergency preparedness programs for a maternal arrest. PMID:23956861

  17. Dynamic resetting of the human circadian pacemaker by intermittent bright light

    NASA Technical Reports Server (NTRS)

    Rimmer, D. W.; Boivin, D. B.; Shanahan, T. L.; Kronauer, R. E.; Duffy, J. F.; Czeisler, C. A.

    2000-01-01

    In humans, experimental studies of circadian resetting typically have been limited to lengthy episodes of exposure to continuous bright light. To evaluate the time course of the human endogenous circadian pacemaker's resetting response to brief episodes of intermittent bright light, we studied 16 subjects assigned to one of two intermittent lighting conditions in which the subjects were presented with intermittent episodes of bright-light exposure at 25- or 90-min intervals. The effective duration of bright-light exposure was 31% or 63% compared with a continuous 5-h bright-light stimulus. Exposure to intermittent bright light elicited almost as great a resetting response compared with 5 h of continuous bright light. We conclude that exposure to intermittent bright light produces robust phase shifts of the endogenous circadian pacemaker. Furthermore, these results demonstrate that humans, like other species, exhibit an enhanced sensitivity to the initial minutes of bright-light exposure.

  18. Ca2+-regulated-cAMP/PKA signaling in cardiac pacemaker cells links ATP supply to demand

    PubMed Central

    Yaniv, Yael; Juhaszova, Magdalena; Lyashkov, Alexey E.; Spurgeon, Harold A.; Sollott, Steven J.; Lakatta, Edward G.

    2011-01-01

    Rationale In sinoatrial node cells (SANC), Ca2+ activates adenylate cyclase (AC) to generate a high basal level of cAMP-mediated/protein kinase A (PKA)-dependent phosphorylation of Ca2+ cycling proteins. These result in spontaneous sarcoplasmic-reticulum (SR) generated rhythmic Ca2+ oscillations during diastolic depolarization, that not only trigger the surface membrane to generate rhythmic action potentials (APs), but, in a feed-forward manner, also activate AC/PKA signaling. ATP is consumed to pump Ca2+ to the SR, to produce cAMP, to support contraction and to maintain cell ionic homeostasis. Objective Since a negative feedback mechanism links ATP-demand to ATP production, we hypothesized that (1) both basal ATP supply and demand in SANC would be Ca2+-cAMP/PKA dependent; and (2) due to its feed–forward nature, a decrease in flux through the Ca2+-cAMP/PKA signaling axis will reduce the basal ATP production rate. Methods and Results O2 consumption in spontaneous beating SANC was comparable to ventricular myocytes (VM) stimulated at 3 Hz. Graded reduction of basal Ca2+-cAMP/PKA signaling to reduce ATP demand in rabbit SANC produced graded ATP depletion (r2=0.96), and reduced O2 consumption and flavoprotein fluorescence. Neither inhibition of glycolysis, selectively blocking contraction nor specific inhibition of mitochondrial Ca2+ flux reduced the ATP level. Conclusions Feed-forward basal Ca2+-cAMP/PKA signaling both consumes ATP to drive spontaneous APs in SANC and is tightly linked to mitochondrial ATP production. Interfering with Ca2+-cAMP/PKA signaling not only slows the firing rate and reduces ATP consumption, but also appears to reduce ATP production so that ATP levels fall. This distinctly differs from VM, which lack this feed-forward basal cAMP/PKA signaling, and in which ATP level remains constant when the demand changes. PMID:21835182

  19. Assessing Health Literacy in Urban Patients With Implantable Cardioverter Defibrillators and Pacemakers.

    PubMed

    Hickey, Kathleen T; Sciacca, Robert R; Gonzalez, Paul; Castillo, Carmen; Frulla, Ashton

    2015-01-01

    Functional health literacy (FHL) has become an increasingly prevalent topic of discussion in patient health and well-being. Although FHL has been studied in a variety of populations, it has not been investigated in patients with pacemakers and implantable cardioverter defibrillators (ICDs).The purpose of this study was to evaluate FHL in a primarily older, urban-dwelling ICD/pacemaker population. A secondary objective was to compare 2 commonly used instruments for assessing FHL.A convenience sample of 116 patients was recruited from an urban ICD/pacemaker clinic. Participants were asked to complete the Short Test of Functional Health Literacy in Adults (STOFHLA) followed by the Test of Functional Health Literacy in Adults to assess reading comprehension and numeracy. Logistic regression was used to assess the association between FHL and patient descriptors.The population was 68 ± 13 years of age, and 62.7% were men. The sample was ethnically diverse: 37.1% white, 39.7% Hispanic, and 22.4% African American; 77.4% of the population reported finishing high school. Of the 109 completing the Test of Functional Health Literacy in Adults, 60.6% had adequate FHL, 10.1% had marginal FHL, and 29.4% had inadequate FHL. The presence of coexisting chronic conditions such as diabetes mellitus, hyperlipidemia, and hypertension was associated with inadequate/marginal FHL (P = .007, P = .004, and P = .02, respectively). Of the 113 completing STOFHLA, 67.3% had adequate FHL, 7.1% had marginal FHL, and 25.7% had inadequate FHL. The presence of diabetes mellitus, hyperlipidemia, and hypertension was also associated with inadequate/marginal FHL as assessed by STOFHLA (P = .009, P = .02, and P = .004, respectively).In this older, urban, ICD/pacemaker population, approximately 40% had inadequate/marginal FHL. These results warrant further investigation of FHL in other cardiovascular populations. PMID:25090052

  20. Traveling waves and dynamical formation of autonomous pacemakers in a bistable medium with periodic boundary conditions

    NASA Astrophysics Data System (ADS)

    Shepelev, Igor A.; Vadivasova, Tatiana E.; Postnov, Dmitry E.

    2015-03-01

    The problem of spatiotemporal pattern formation in the wall of arterial vesselsmay be reduced to 1D or 2D models of nonlinear active medium. We address this problem using the discrete array of non-oscillating (bistable) active units. We show how the specific choice of initial conditions in a 1D model with periodic boundary conditions triggers the self-sustained behaviour. We reveal the core of observed effects being the dynamical formation of localized (few-element size) autonomous pacemakers.

  1. The location of pacemakers in the uteri of pregnant guinea pigs and rats.

    PubMed

    Lammers, Wim J E P; Stephen, Betty; Al-Sultan, Mahmood Ahmed; Subramanya, Sandeep B; Blanks, Andrew M

    2015-12-01

    The pregnant uterus is a smooth muscle organ whose pattern of contraction is dictated by the propagation of electrical impulses. Such electrical activity may originate from one or more pacemakers, but the location of these sites has not yet been determined. To detect the location of the pacemaker in the gravid uterus, two approaches were used: 1) determine the site from where the contraction started using isolated uteri from the pregnant guinea pig, and videotape their contractions; and 2) record, in isolated uteri from pregnant term rats, with 240 extracellular electrodes simultaneously, and determine where the electrical bursts started. In both the contractile and electrophysiological experiments, there was not a single, specific pacemaker area. However, most contractions (guinea pig 87%) and bursts (rat 76%) started close to the mesometrial border (mean 2.7 ± 4.0 mm SD in guinea pigs and 1.3 ± 1.4 mm in rats). In addition, in the rat, most sites of initiations were located closer to the ovarial end of the horn (mean distance from the ovarial end 6.0 ± 6.2 mm SD), whereas such an orientation was not seen in the guinea pig. In both guinea pig and rat uteri at term, there is not one specific pacemaker area. Rather, contractile and electrical activity may arise from any site, with the majority starting close to the mesometrial border. Furthermore, in the rat, most activities started at the ovarial end of the horn. This may suggest a slightly different pattern of contraction in both species. PMID:26377559

  2. Plasma Exchange for Urgent Apixaban Reversal in a Case of Hemorrhagic Tamponade after Pacemaker Implantation

    PubMed Central

    Reyes, Meredith A.; Seger, John J.

    2015-01-01

    We report the case of an 82-year-old man in whom hemorrhagic pericardial effusion occurred one week after pacemaker implantation, while he was taking apixaban. Few therapies exist for reversing the anti-Xa effect of apixaban. To reverse anticoagulation, our patient underwent plasma exchange, which facilitated pericardiocentesis and prevented possible surgical intervention. To our knowledge, this is the first report of the use of plasmapheresis to reverse the anticoagulant effect of apixaban. PMID:26413023

  3. Generation of locomotion rhythms without inhibition in vertebrates: the search for pacemaker neurons.

    PubMed

    Li, Wen-Chang

    2011-12-01

    Locomotion rhythms are thought to be generated by neurons in the central-pattern-generator (CPG) circuit in the spinal cord. Synaptic connections in the CPG and pacemaker properties in certain CPG neurons, both may contribute to generation of the rhythms. In the half-center model proposed by Graham Brown a century ago, reciprocal inhibition plays a critical role. However, in all vertebrate preparations examined, rhythmic motor bursts can be induced when inhibition is blocked in the spinal cord. Without inhibition, neuronal pacemaker properties may become more important in generation of the rhythms. Pacemaker properties have been found in motoneurons and some premotor interneurons in different vertebrates and they can be dependent on N-Methyl-d-aspartate (NMDA) receptors (NMDAR) or rely on other ionic currents like persistent inward currents. In the swimming circuit of the hatchling Xenopus tadpole, there is substantial evidence that emergent network properties can give rise to swimming rhythms. During fictive swimming, excitatory interneurons (dINs) in the caudal hindbrain fire earliest on each swimming cycle and their spikes drive the firing of other CPG neurons. Regenerative dIN firing itself relies on reciprocal inhibition and background excitation. We now find that the activation of NMDARs can change dINs from firing singly at rest to current injection to firing repetitively at swimming frequencies. When action potentials are blocked, some intrinsic membrane potential oscillations at about 10 Hz are revealed, which may underlie repetitive dIN firing during NMDAR activation. In confirmation of this, dIN repetitive firing persists in NMDA when synaptic transmission is blocked by Cd(2+). When inhibition is blocked, only dINs and motoneurons are functional in the spinal circuit. We propose that the conditional intrinsic NMDAR-dependent pacemaker firing of dINs can drive the production of swimming-like rhythms without the participation of inhibitory neurotransmission. PMID:21562024

  4. Global Availability of Cardiac Rehabilitation

    PubMed Central

    Turk-Adawi, Karam; Grace, Sherry L.

    2015-01-01

    The most prevalent non-communicable disease globally, namely cardiovascular disease (CVD), is also the leading cause of mortality, with over 80% of the deaths occurring in low- and middle-income countries. To lessen the impact of CVDs on individuals and societies, a comprehensive approach is needed. Cardiac rehabilitation (CR) involves delivery of structured exercise, education and risk reduction, in a cost-effective manner. Robust evidence demonstrates it reduces mortality up to 25%, improves functional capacity, as well as decreases re-hospitalization. Despite its benefits, and clinical practice guideline recommendations to refer cardiac patients, CR programs are grossly under-used. Worldwide, there is low availability of CR; only 38.8% of countries globally have CR programs. Specifically, 68.0% of high-income and 23% of LMICs (28.2% for middle- and 8.3% for low-income countries) have CR. CR density estimates ranged from 1 program per 0.1–6.4 million inhabitants. CR availability is much lower than that of other evidence-based secondary prevention therapies, such as revascularization and pharmacological therapies. Multi-level strategies to augment CR capacity and availability at national and international levels such as supportive public health policies, systematic referral strategies, and alternative models of delivery are needed. PMID:25027487

  5. An Update: The Cardiac Wellness Training Project.

    ERIC Educational Resources Information Center

    Zinn, Lorraine; Long, Patrick

    1983-01-01

    This article reports on the scope of activities and the effectiveness of a Colorado program that trained community park and recreation personnel to carry out local cardiac wellness services. Participants were trained to provide rehabilitation and fitness activities for those recovering from heart attacks or surgery and for other high-risk persons.…

  6. Simulations of light effects on the human circadian pacemaker: implications for assessment of intrinsic period

    NASA Technical Reports Server (NTRS)

    Klerman, E. B.; Dijk, D. J.; Kronauer, R. E.; Czeisler, C. A.

    1996-01-01

    The sensitivity of the human circadian system to light has been the subject of considerable debate. Using computer simulations of a recent quantitative model for the effects of light on the human circadian system, we investigated these effects of light during different experimental protocols. The results of the simulations indicate that the nonuniform distribution over the circadian cycle of exposure to ordinary room light seen in classical free-run studies, in which subjects select their exposure to light and darkness, can result in an observed period of approximately 25 h, even when the intrinsic period of the subject's endogenous circadian pacemaker is much closer to 24 h. Other simulation results suggest that accurate assessment of the true intrinsic period of the human circadian pacemaker requires low ambient light intensities (approximately 10-15 lx) during scheduled wake episodes, desynchrony of the imposed light-dark cycle from the endogenous circadian oscillator, and a study length of at least 20 days. Although these simulations await further experimental substantiation, they highlight the sensitivity to light of the human circadian system and the potential confounding influence of light on the assessment of the intrinsic period of the circadian pacemaker.

  7. From two competing oscillators to one coupled-clock pacemaker cell system.

    PubMed

    Yaniv, Yael; Lakatta, Edward G; Maltsev, Victor A

    2015-01-01

    At the beginning of this century, debates regarding "what are the main control mechanisms that ignite the action potential (AP) in heart pacemaker cells" dominated the electrophysiology field. The original theory which prevailed for over 50 years had advocated that the ensemble of surface membrane ion channels (i.e., "M-clock") is sufficient to ignite rhythmic APs. However, more recent experimental evidence in a variety of mammals has shown that the sarcoplasmic reticulum (SR) acts as a "Ca(2+)-clock" rhythmically discharges diastolic local Ca(2+) releases (LCRs) beneath the cell surface membrane. LCRs activate an inward current (likely that of the Na(+)/Ca(2+) exchanger) that prompts the surface membrane "M-clock" to ignite an AP. Theoretical and experimental evidence has mounted to indicate that this clock "crosstalk" operates on a beat-to-beat basis and determines both the AP firing rate and rhythm. Our review is focused on the evolution of experimental definition and numerical modeling of the coupled-clock concept, on how mechanisms intrinsic to pacemaker cell determine both the heart rate and rhythm, and on future directions to develop further the coupled-clock pacemaker cell concept. PMID:25741284

  8. Involvement of ryanodine receptors in pacemaker Ca2+ oscillation in murine gastric ICC.

    PubMed

    Liu, Hong-Nian; Ohya, Susumu; Wang, Jing; Imaizumi, Yuji; Nakayama, Shinsuke

    2005-03-11

    Using a cell cluster preparation from the stomach smooth muscle tissue of mice, we measured intracellular Ca(2+) oscillations in interstitial cells of Cajal (ICCs) in the presence of nifedipine. Pacemaker [Ca(2+)](i) activity in ICCs was significantly suppressed by caffeine application and restored after washout. Application of either ryanodine or FK-506 terminated the pacemaker [Ca(2+)](i) activity irreversibly. Immunostaining of smooth muscle tissue showed that c-Kit-immunopositive cells (that form network-like structure cells in the myenteric plexus, equivalent to ICCs) clearly express ryanodine receptors (RyR). RT-PCR revealed that ICCs (identified with c-Kit-immunoreactivity) predominantly express type 3 RyR (RyR3). Furthermore, the FK-binding proteins 12 and 12.6, both of which would interact with RyR3, were detected. In conclusion, we provide first evidence for the essential contribution of RyR to generating pacemaker activity in gastric motility. Similar mechanisms might account for spontaneous rhythmicity seen in smooth muscle tissues distributed in the autonomic nervous system. PMID:15694396

  9. Cardiac Arrest Resuscitation.

    PubMed

    Guyette, Francis X; Reynolds, Joshua C; Frisch, Adam

    2015-08-01

    Cardiac arrest is a dynamic disease that tests the multitasking and leadership abilities of emergency physicians. Providers must simultaneously manage the logistics of resuscitation while searching for the cause of cardiac arrest. The astute clinician will also realize that he or she is orchestrating only one portion of a larger series of events, each of which directly affects patient outcomes. Resuscitation science is rapidly evolving, and emergency providers must be familiar with the latest evidence and controversies surrounding resuscitative techniques. This article reviews evidence, discusses controversies, and offers strategies to provide quality cardiac arrest resuscitation. PMID:26226873

  10. Recalls of Cardiac Implants in the Last Decade: What Lessons Can We Learn?

    PubMed Central

    Schaller, Sandra; Kolominsky-Rabas, Peter L.

    2015-01-01

    Background Due to an ageing population and demographic changes worldwide, a higher prevalence of heart disease is forecasted, which causes an even higher demand for cardiac implants in future. The increasing high incidence of clinical adverse events attributed especially to high-risk medical devices has led an advocated change from many stakeholders. This holds especially true for devices like cardiac implants, with their high-risk nature and high complication rates associated with considerable mortality, due to their frequent use in older populations with frequent co-morbidities. To ensure patients’ safety, the objective of this study is to analyze different cardiac implants recall reasons and different recall systems, based on an overview of the recalls of cardiac implant medical devices in the last decade. On the basis of the results from this structured analysis, this study provides recommendations on how to avoid such recalls from a manufacturer perspective, as well as how to timely react to an adverse event from a post-surveillance system perspective. Methods and Findings A systematic search of cardiac implant recalls information has been performed in the PubMed, ScienceDirect and Scopus databases, as well as data sources in regulatory authorities from 193 UN Member States. Data has been extracted for the years 2004-2014 with the following criteria applied: cardiac implant medical device recalls and reasons for recall, associated harm or risk to patients. From the data sources described above, eleven regulatory authorities and 103 recall reports have been included in this study. The largest cardiac implant categories include ICDs 40.8%, pacemakers 14.5% and stents 14.5%. Regarding the recall reasons, the majority of reports were related to device battery problems (33.0%) and incorrect therapy delivery (31.1%). From a total of 103 recall reports, five reported death and serious injuries. Our review highlights weaknesses in the current cardiac implant recall system, including data reporting and management issues and provides recommendations for the improvement of safety information and management. Conclusion Due to the mortality associated with the nature of cardiac implants, the traceability and transparency of safety hazards information is crucial. By a structured analysis of recall reasons and their efficient management, important knowledge is gained to inform an effective safety-reporting system for monitoring the safety of cardiac implanted patients, ideally by building up cardiac implant registries worldwide in the future. PMID:25962074

  11. Sudden Cardiac Arrest

    MedlinePLUS

    ... Cardiac Arrest ( SCA ) occurs when the heart stops beating, abruptly and without warning. If this happens, blood ... when SCA occurs. During SCA , the heart stops beating and no blood is pumped to the rest ...

  12. Cardiac ablation procedures

    MedlinePLUS

    ... for performing cardiac ablation: Radiofrequency ablation uses heat energy to eliminate the problem area. Cryoablation uses very ... is used to send electrical (or sometimes cold) energy to the problem area. This creates a small ...

  13. Cardiac Risk Assessment

    MedlinePLUS

    ... helpful? Formal name: Cardiac Risk Assessment Related tests: Lipid Profile , VLDL Cholesterol , hs-CRP , Lp(a) Overview | ... on Coronary artery disease: Tests and diagnosis .) The lipid profile is the most important blood test for ...

  14. Missed cardiac tamponade

    PubMed Central

    Thomson-Moore, Alexandra Louise

    2011-01-01

    Cardiac tamponade can have an insidious onset, becoming life threatening when an adequate cardiac output can no longer be maintained. This case provides an example of a presentation where all the classic signs were present but unfortunately they were missed, in this way providing good revision of what these signs are. It gives some anaesthetic and procedure based perspectives for this rare presentation. It is noteworthy for the speed at which symptoms and signs resolved after the tamponade was relieved. PMID:22679253

  15. Cardiac Applications of Optogenetics

    PubMed Central

    Ambrosi, Christina M.; Klimas, Aleksandra; Yu, Jinzhu; Entcheva, Emilia

    2014-01-01

    In complex multicellular systems, such as the brain or the heart, the ability to selectively perturb and observe the response of individual components at the cellular level and with millisecond resolution in time, is essential for mechanistic understanding of function. Optogenetics uses genetic encoding of light sensitivity (by the expression of microbial opsins) to provide such capabilities for manipulation, recording, and control by light with cell specificity and high spatiotemporal resolution. As an optical approach, it is inherently scalable for remote and parallel interrogation of biological function at the tissue level; with implantable miniaturized devices, the technique is uniquely suitable for in vivo tracking of function, as illustrated by numerous applications in the brain. Its expansion into the cardiac area has been slow. Here, using examples from published research and original data, we focus on optogenetics applications to cardiac electrophysiology, specifically dealing with the ability to manipulate membrane voltage by light with implications for cardiac pacing, cardioversion, cell communication, and arrhythmia research, in general. We discuss gene and cell delivery methods of inscribing light sensitivity in cardiac tissue, functionality of the light-sensitive ion channels within different types of cardiac cells, utility in probing electrical coupling between different cell types, approaches and design solutions to all-optical electrophysiology by the combination of optogenetic sensors and actuators, and specific challenges in moving towards in vivo cardiac optogenetics. PMID:25035999

  16. Cardiac applications of optogenetics.

    PubMed

    Ambrosi, Christina M; Klimas, Aleksandra; Yu, Jinzhu; Entcheva, Emilia

    2014-08-01

    In complex multicellular systems, such as the brain or the heart, the ability to selectively perturb and observe the response of individual components at the cellular level and with millisecond resolution in time, is essential for mechanistic understanding of function. Optogenetics uses genetic encoding of light sensitivity (by the expression of microbial opsins) to provide such capabilities for manipulation, recording, and control by light with cell specificity and high spatiotemporal resolution. As an optical approach, it is inherently scalable for remote and parallel interrogation of biological function at the tissue level; with implantable miniaturized devices, the technique is uniquely suitable for in vivo tracking of function, as illustrated by numerous applications in the brain. Its expansion into the cardiac area has been slow. Here, using examples from published research and original data, we focus on optogenetics applications to cardiac electrophysiology, specifically dealing with the ability to manipulate membrane voltage by light with implications for cardiac pacing, cardioversion, cell communication, and arrhythmia research, in general. We discuss gene and cell delivery methods of inscribing light sensitivity in cardiac tissue, functionality of the light-sensitive ion channels within different types of cardiac cells, utility in probing electrical coupling between different cell types, approaches and design solutions to all-optical electrophysiology by the combination of optogenetic sensors and actuators, and specific challenges in moving towards in vivo cardiac optogenetics. PMID:25035999

  17. Hippo pathway effector Yap promotes cardiac regeneration

    PubMed Central

    Xin, Mei; Kim, Yuri; Sutherland, Lillian B.; Murakami, Masao; Qi, Xiaoxia; McAnally, John; Porrello, Enzo R.; Mahmoud, Ahmed I.; Tan, Wei; Shelton, John M.; Richardson, James A.; Sadek, Hesham A.; Bassel-Duby, Rhonda; Olson, Eric N.

    2013-01-01

    The adult mammalian heart has limited potential for regeneration. Thus, after injury, cardiomyocytes are permanently lost, and contractility is diminished. In contrast, the neonatal heart can regenerate owing to sustained cardiomyocyte proliferation. Identification of critical regulators of cardiomyocyte proliferation and quiescence represents an important step toward potential regenerative therapies. Yes-associated protein (Yap), a transcriptional cofactor in the Hippo signaling pathway, promotes proliferation of embryonic cardiomyocytes by activating the insulin-like growth factor and Wnt signaling pathways. Here we report that mice bearing mutant alleles of Yap and its paralog WW domain containing transcription regulator 1 (Taz) exhibit gene dosage-dependent cardiac phenotypes, suggesting redundant roles of these Hippo pathway effectors in establishing proper myocyte number and maintaining cardiac function. Cardiac-specific deletion of Yap impedes neonatal heart regeneration, resulting in a default fibrotic response. Conversely, forced expression of a constitutively active form of Yap in the adult heart stimulates cardiac regeneration and improves contractility after myocardial infarction. The regenerative activity of Yap is correlated with its activation of embryonic and proliferative gene programs in cardiomyocytes. These findings identify Yap as an important regulator of cardiac regeneration and provide an experimental entry point to enhance this process. PMID:23918388

  18. Depression and cardiac disease: a review.

    PubMed

    Celano, Christopher M; Huffman, Jeff C

    2011-01-01

    Depression is highly prevalent in cardiac patients, with 20% to 40% of patients meeting criteria for major depressive disorder or experiencing an elevation in depressive symptoms. These depressive symptoms are often chronic and persistent, and they have been associated with the development and progression of coronary artery disease, worse health-related quality of life, poor physical functioning, recurrent cardiac events, and a 2- to 2.5-fold increased risk of mortality. Impaired adherence to health behaviors and adverse physiological effects of depression, including inflammation, endothelial dysfunction, platelet hyperactivity, and autonomic nervous system abnormalities, may link depression with adverse cardiac outcomes. Pharmacologic and psychotherapeutic interventions appear to be safe and effective at reducing depressive symptoms in patients with cardiovascular disease and may impact cardiac outcomes. Unfortunately, depression often is unrecognized and untreated in this population, despite the availability of brief screening tools that can be used for this purpose. We recommend the routine screening of cardiac patients for depression when there are adequate mechanisms for management and referral, such as available consulting psychiatrists or care management programs that facilitate the delivery of pharmacologic and psychotherapeutic treatments in this vulnerable population. PMID:21464641

  19. Development of a postgraduate interventional cardiac nursing curriculum.

    PubMed

    Currey, Judy; White, Kevin; Rolley, John; Oldland, Elizabeth; Driscoll, Andrea

    2015-11-01

    Interventional cardiology practices have advanced immensely in the last two decades, but the educational preparation of the workforce in cardiac catheter laboratories has not seen commensurate changes. Although on-the-job training has sufficed in the past, recognition of this workforce as a specialty practice domain now demands specialist educational preparation. The aim of this paper is to present the development of an interventional cardiac nursing curriculum nested within a Master of Nursing Practice in Australia. International and national health educational principles, teaching and learning theories and professional frameworks and philosophies are foundational to the program designed for interventional cardiac specialist nurses. These broader health, educational and professional underpinnings will be described to illustrate their application to the program's theoretical and clinical components. Situating interventional cardiac nursing within a Master's degree program at University provides nurses with the opportunities to develop high level critical thinking and problem solving knowledge and skills. PMID:25687694

  20. Performance of a Wirelessly Rechargeable Pacemaker for Gastric Stimulation Sanchali Deb, Thomas Abell, Shou J. Tang, Smitha M.N. Rao, Christopher Lahr, and J.-C Chiao

    E-print Network

    Chiao, Jung-Chih

    setting produces a different electrical pulse train. All the settings were tested and verified after each pacemaker device surgically implanted in animal models (pig). The gastric motility was categorized based the pacemaker stopped working, back to the full capacity within 30 minutes. TABLE 1. EGG Results for Different

  1. Cardiac applications of PET.

    PubMed

    Sarikaya, Ismet

    2015-10-01

    Routine use of cardiac positron emission tomography (PET) applications has been increasing but has not replaced cardiac single-photon emission computerized tomography (SPECT) studies yet. The majority of cardiac PET tracers, with the exception of fluorine-18 fluorodeoxyglucose (18F-FDG), are not widely available, as they require either an onsite cyclotron or a costly generator for their production. 18F-FDG PET imaging has high sensitivity for the detection of hibernating/viable myocardium and has replaced Tl-201 SPECT imaging in centers equipped with a PET/CT camera. PET myocardial perfusion imaging with various tracers such as Rb-82, N-13 ammonia, and O-15 H2O has higher sensitivity and specificity than myocardial perfusion SPECT for the detection of coronary artery disease (CAD). In particular, quantitative PET measurements of myocardial perfusion help identify subclinical coronary stenosis, better define the extent and severity of CAD, and detect ischemia when there is balanced reduction in myocardial perfusion due to three-vessel or main stem CAD. Fusion images of PET perfusion and CT coronary artery calcium scoring or CT coronary angiography provide additional complementary information and improve the detection of CAD. PET studies with novel 18F-labeled perfusion tracers such as 18F-flurpiridaz and 18F-FBnTP have yielded high sensitivity and specificity in the diagnosis of CAD. These tracers are still being tested in humans, and, if approved for clinical use, they will be commercially and widely available. In addition to viability studies, 18F-FDG PET can also be utilized to detect inflammation/infection in various conditions such as endocarditis, sarcoidosis, and atherosclerosis. Some recent series have obtained encouraging results for the detection of endocarditis in patients with intracardiac devices and prosthetic valves. PET tracers for cardiac neuronal imaging, such as C-11 HED, help assess the severity of heart failure and post-transplant cardiac reinnervation, and understand the pathogenesis of arrhytmias. The other uncommon applications of cardiac PET include NaF imaging to identify calcium deposition in atherosclerotic plaques and ?-amyloid imaging to diagnose cardiac amyloid involvement. 18F-FDG imaging with a novel PET/MR camera has been reported to be very sensitive and specific for the differentiation between malignant and nonmalignant cardiac masses. The other potential applications of PET/MR are cardiac infectious/inflammatory conditions such as endocarditis. PMID:26035516

  2. Membranes as a possible pacemaker of metabolism in cypriniform fish: does phylogeny matter?

    PubMed

    Gonzalez, Alex; Pagé, Benoît; Weber, Jean-Michel

    2015-08-01

    The 'membrane pacemaker theory of metabolism' proposes that membranes set metabolic rate by modulating protein activity, and thus purports to explain membrane fatty acid allometry. This relationship has never been tested across species in ectotherms. After accounting for phylogeny, recent analyses have failed to support this theory based on correlations between muscle membrane composition and body mass across mammals. Therefore, the goal of this study was to seek phylogenetically corrected correlations between membrane composition, body mass and calcium-ATPase activity, using 12 species of closely related cypriniform fish (4-5500?g) covering a much narrower genetic scale than in previous tests. The results show that fish membrane unsaturation decreases with mass, but through different mechanisms from those in endotherms: 16:0 replacing 22:6 in muscle and 18:0 replacing 16:1, 18:1 and 18:2 in liver. This shows that allometric patterns differ between endotherms and ectotherms as well as between tissues. After accounting for phylogeny, however, almost all these relationships lose significance except for overall unsaturation. No relationship between calcium-ATPase activity and mass or phospholipid composition was detected. This study shows that membrane unsaturation of cypriniforms decreases with mass, but that genetic cues unrelated to size account for differences in the relative abundance of individual fatty acids. The membrane pacemaker concept accurately predicts general membrane properties such as unsaturation, but fails to explain finer scale allometric patterns. Future examinations of the membrane pacemaker hypothesis will have to take into account that allometric patterns vary between endotherms and ectotherms and between tissues of the same animal class. PMID:26089526

  3. Comparison of impedance minute ventilation and direct measured minute ventilation in a rate adaptive pacemaker.

    PubMed

    Simon, Ron; Ni, Quan; Willems, Roger; Hartley, Jesse W; Daum, Douglas R; Lang, Douglas; Ward, Kevin; Gill, Jaswinder

    2003-11-01

    Respiration rate (RR) and minute ventilation (MV) provide important clinical information on the state of the patient. This study evaluated the accuracy of determining these using a pacemaker impedance sensor. In 20 patients who were previously implanted with a Guidant PULSAR MAX group of pacemakers, the telemetered impedance sensor waveform was recorded simultaneously with direct volume respiration waveforms as measured by a pneumatometer. Patients underwent 30 minutes of breathing tests while supine and standing, and a 10-minute ergonometer bicycle exercise test at a workload of 50 W. Breathing tests included regular and rapid-shallow breathing sequences. RR was determined by a computerized algorithm, from impedance and respiration signals. The mean RR by impedance was 21.3 +/- 7.7 breaths/min, by direct volume was 21.1 +/- 7.6 breaths/min, range 7-66, the mean difference of RR measured by the impedance sensor, as compared with the true measurement, being 0.2 +/- 2.1 breaths/min. During the entire exercise, the mean correlation coefficient between impedance (iMV) and direct measured MV was 0.96 +/- 0.03, slope 0.13 +/- 0.05 L/Omega and range 0.07-0.26 L/Omega. Bland-Altman limits of agreement were +/- 4.6 L/min for MV versus iMV with each patient calibrated separately. The correlation coefficient for iMV versus MV over the entire 10 minutes of exercise, including the initial 4 minutes of exercise, was 0.99. The transthoracic impedance sensor of an implanted pacemaker can accurately detect respiration parameters. There was a large variation between subjects in the iMV versus MV slope during a bicycle exercise test, whereas for each subject, the slope was stable during submaximal bicycle exercise. PMID:14622315

  4. Beam Profile Disturbances from Implantable Pacemakers or Implantable Cardioverter-Defibrillator Interactions

    SciTech Connect

    Gossman, Michael S.; Nagra, Bipinpreet; Graves-Calhoun, Alison; Wilkinson, Jeffrey

    2011-01-01

    The medical community is advocating for progressive improvement in the design of implantable cardioverter-defibrillators and implantable pacemakers to accommodate elevations in dose limitation criteria. With advancement already made for magnetic resonance imaging compatibility in some, a greater need is present to inform the radiation oncologist and medical physicist regarding treatment planning beam profile changes when such devices are in the field of a therapeutic radiation beam. Treatment plan modeling was conducted to simulate effects induced by Medtronic, Inc.-manufactured devices on therapeutic radiation beams. As a continuation of grant-supported research, we show that radial and transverse open beam profiles of a medical accelerator were altered when compared with profiles resulting when implantable pacemakers and cardioverter-defibrillators are placed directly in the beam. Results are markedly different between the 2 devices in the axial plane and the sagittal planes. Vast differences are also presented for the therapeutic beams at 6-MV and 18-MV x-ray energies. Maximum changes in percentage depth dose are observed for the implantable cardioverter-defibrillator as 9.3% at 6 MV and 10.1% at 18 MV, with worst distance to agreement of isodose lines at 2.3 cm and 1.3 cm, respectively. For the implantable pacemaker, the maximum changes in percentage depth dose were observed as 10.7% at 6 MV and 6.9% at 18 MV, with worst distance to agreement of isodose lines at 2.5 cm and 1.9 cm, respectively. No differences were discernible for the defibrillation leads and the pacing lead.

  5. Sensitivity of the human circadian pacemaker to nocturnal light: melatonin phase resetting and suppression

    NASA Technical Reports Server (NTRS)

    Zeitzer, J. M.; Dijk, D. J.; Kronauer, R.; Brown, E.; Czeisler, C.

    2000-01-01

    Ocular exposure to early morning room light can significantly advance the timing of the human circadian pacemaker. The resetting response to such light has a non-linear relationship to illuminance. The dose-response relationship of the human circadian pacemaker to late evening light of dim to moderate intensity has not been well established. Twenty-three healthy young male and female volunteers took part in a 9 day protocol in which a single experimental light exposure6.5 h in duration was given in the early biological night. The effects of the light exposure on the endogenous circadian phase of the melatonin rhythm and the acute effects of the light exposure on plasma melatonin concentration were calculated. We demonstrate that humans are highly responsive to the phase-delaying effects of light during the early biological night and that both the phase resetting response to light and the acute suppressive effects of light on plasma melatonin follow a logistic dose-response curve, as do many circadian responses to light in mammals. Contrary to expectations, we found that half of the maximal phase-delaying response achieved in response to a single episode of evening bright light ( approximately 9000 lux (lx)) can be obtained with just over 1 % of this light (dim room light of approximately 100 lx). The same held true for the acute suppressive effects of light on plasma melatonin concentrations. This indicates that even small changes in ordinary light exposure during the late evening hours can significantly affect both plasma melatonin concentrations and the entrained phase of the human circadian pacemaker.

  6. Identification of Bacteriology and Risk Factor Analysis of Asymptomatic Bacterial Colonization in Pacemaker Replacement Patients

    PubMed Central

    Chu, Xian-Ming; Yu, Hua; Sun, Xue-Xia; An, Yi; Li, Bing; Li, Xue-Bin

    2015-01-01

    Background Recent researches revealed that asymptomatic bacterial colonization on PMs might be ubiquitous and increase the risk of clinical PM infection. Early diagnosis of patients with asymptomatic bacterial colonization could provide opportunity for targeted preventive measures. Objective The present study explores the incidence of bacterial colonization of generator pockets in pacemaker replacement patients without signs of infection, and to analyze risk factors for asymptomatic bacterial colonization. Methods From June 2011 to December 2013, 118 patients underwent pacemaker replacement or upgrade. Identification of bacteria was carried out by bacterial culture and 16S rRNA sequencing. Clinical risk characteristics were analyzed. Results The total bacterial positive rate was 37.3% (44 cases), and the coagulase-negative Staphylococcus aureus detection rate was the highest. Twenty two (18.6%) patients had positive bacterial culture results, of which 50% had coagulase-negative staphylococcus. The bacterial DNA detection rate was 36.4 % (43 cases). Positive bacterial DNA results from pocket tissues and the surface of the devices were 22.0% and 29.7%, respectively. During follow-up (median, 27.0 months), three patients (6.8%, 3/44) became symptomatic with the same genus of microorganism, S. aureus (n=2) and S. epidermidis (n=1). Multivariable logistic regression analysis showed that history of bacterial infection, use of antibiotics, application of antiplatelet drugs, replacement frequency were independent risk factors for asymptomatic bacterial colonization. Conclusion There was a high incidence of asymptomatic bacterial colonization in pacemaker patients with independent risk factors. Bacterial culture combined genetic testing could improve the detection rate. PMID:25768661

  7. Association of sleep-wake habits in older people with changes in output of circadian pacemaker

    NASA Technical Reports Server (NTRS)

    Czeisler, C. A.; Dumont, M.; Duffy, J. F.; Steinberg, J. D.; Richardson, G. S.; Brown, E. N.; Sanchez, R.; Rios, C. D.; Ronda, J. M.

    1992-01-01

    Many elderly people complain of disturbed sleep patterns but there is not evidence that the need to sleep decreases with age; it seems rather that the timing and consolidation of sleep change. We tried to find out whether there is a concurrent change in the output of the circadian pacemaker with age. The phase and amplitude of the pacemaker's output were assessed by continuous measurement of the core body temperature during 40 h of sustained wakefulness under constant behavioural and environmental conditions. 27 young men (18-31 years) were compared with 21 older people (65-85 years; 11 men, 10 women); all were healthy and without sleep complaints. The mean amplitude of the endogenous circadian temperature oscillation (ECA) was 40% greater in young men than in the older group. Older men had a lower mean temperature ECA than older women. The minimum of the endogenous phase of the circadian temperature oscillation (ECP) occurred 1 h 52 min earlier in the older than in the young group. Customary bedtimes and waketimes were also earlier in the older group, as was their daily alertness peak. There was a close correlation between habitual waketime and temperature ECP in young men, which may lose precision with age, especially among women. These findings provide evidence for systematic age-related changes in the output of the human circadian pacemaker. We suggest that these changes may underlie the common complaints of sleep disturbance among elderly people. These changes could reflect the observed age-related deterioration of the hypothalamic nuclei that drive mammalian circadian rhythms.

  8. Dramatically improved left ventricular function after biventricular pacemaker implantation--a case report.

    PubMed

    Bulava, Alan; Lukl, Jan; Skvarilová, Marcela; Marek, Dan

    2005-03-01

    A case study of a patient suffering from severe chronic congestive heart failure resulting from ischemic cardiomyopathy in whom a biventricular (BiV) pacing system was implanted is reported. After a 1-year follow-up, left ventricular (LV) ejection fraction improved dramatically from an initial 15% to 60%, left ventricular end-diastolic diameter decreased, as did left atrial dimension. Tissue Doppler data and acute hemodynamic measurements taken during the biventricular pacemaker implantation procedure are presented. The case represents an exceptional example of left ventricular reverse remodeling with practically normalized left ventricular function after 1 year of synchronized pacing. PMID:15701472

  9. Intracellular calcium and Na+-Ca2+ exchange current in isolated toad pacemaker cells.

    PubMed

    Ju, Y K; Allen, D G

    1998-04-01

    1. Single pacemaker cells were isolated from the sinus venosus of cane toad (Bufo marinus) in order to study the mechanisms involved in the spontaneous firing rate of action potentials. Intracellular calcium concentration ([Ca2+]i) was measured with indo-1 to determine whether [Ca2+]i influenced firing rate. A rapid transient rise of [Ca2+]i was recorded together with each spontaneous action potential. [Ca2+]i at the peak of systole was 655 +/- 64 nM and the minimum at the end of diastole was 195 +/- 15 nM. 2. Reduction of extracellular Ca2+ concentration from 2 to 0.5 mM caused a reduction in both systolic and diastolic [Ca2+]i and the spontaneous firing rate also gradually declined. 3. Application of the acetoxymethyl (AM) ester of BAPTA (10 microM), in order to increase intracellular calcium buffering, caused a decline in systolic and diastolic [Ca2+]i. The firing rate declined progressively until the cells stopped firing after 10-15 min. At the time that firing ceased, the diastolic [Ca2+]i had declined by 141 +/- 38 nM. 4. In the presence of ryanodine (2 microM), which interferes with Ca2+ release from the sarcoplasmic reticulum, the systolic and diastolic [Ca2+]i both declined and the firing rate decreased until the cells stopped firing. At quiescence diastolic [Ca2+]i had declined by 93 +/- 20 nM. 5. Exposure of the cells to Na+-free solution caused a rise in [Ca2+]i which exceeded the systolic level after 4.8 +/- 0.3 s. This rise is consistent with Ca2+ entry on a Na+-Ca2+ exchanger. 6. Rapid application of caffeine (10-20 mM) to cells clamped at -60 mV caused a rapid increase in [Ca2+]i which then spontaneously declined. An inward current with a similar time course to that of [Ca2+]i was also generated. Application of Ni2+ (5 mM) or 2,4-dichlorobenzamil (25 microM) reduced the amplitude of the inward current produced by caffeine by 96 +/- 1 % and 74 +/- 10 %, respectively. In a Na+-free solution the caffeine-induced current was reduced by 93 +/- 7 %. 7. Under a variety of circumstances the diastolic [Ca2+]i showed a close association with pacemaker firing rate. The existence of a Na+-Ca2+ exchanger and its estimated contribution to inward current during the pacemaker potential suggest that the Na+-Ca2+ exchange current makes a contribution to pacemaker activity. PMID:9490832

  10. Radiation from Cardiac Imaging Tests

    MedlinePLUS

    ... User Name Password Sign In Cardiology Patient Page Radiation From Cardiac Imaging Tests Questions You Should Ask ... cardiac imaging techniques computed tomography imaging nuclear medicine radiation Next Section Introduction Many patients are referred by ...

  11. Fetal cardiac scanning today.

    PubMed

    Allan, Lindsey

    2010-07-01

    The ability to examine the structure of the fetal heart in real-time started over 30 years ago now. The field has seen very great advances since then, both in terms of technical improvements in ultrasound equipment and in dissemination of operator skills. A great deal has been learnt about normal cardiac function in the human fetus throughout gestation and how it is affected by pathologies of pregnancy. There is increasing recognition of abnormal heart structure during routine obstetric scanning, allowing referral for specialist diagnosis and counselling. It is now possible to make accurate diagnosis of cardiac malformations as early as 12 weeks of gestation. Early diagnosis of a major cardiac malformation in the fetus can provide the parents with a comprehensive prognosis, enabling them to make the most informed choice about the management of the pregnancy. PMID:20572107

  12. Successful Implantation of Bipolar Epicardial Leads and Dual Chamber Pacemaker in Infant After Postoperative Atrioventricular Heart Block

    PubMed Central

    Omerbasic, Edin; Karabdic, Ilirijana Haxhibeqiri; Tahirovic, Elnur

    2015-01-01

    Total atrioventricular (AV) block is inconvenient and serious complication of open heart surgery. Permanent total AV block requires the implantation of permanent pacemaker in order to allow normal hemodynamics and patient’s survival. In infancy additional challenge is the surgical approach, the selection of electrodes and PM, as well as place of implantation. We are publishing case report of successful double-chamber DDD pacemaker implantation at an infant born with Fallot tetralogy and with low birth weight due to complete AV block after primary surgical correction of these congenital defects. PMID:26236087

  13. Giant Cardiac Cavernous Hemangioma.

    PubMed

    Unger, Eric; Costic, Joseph; Laub, Glenn

    2015-07-01

    We report the case of an asymptomatic giant cardiac cavernous hemangioma in a 71-year-old man. The intracardiac mass was discovered incidentally during surveillance for his prostate cancer; however, the patient initially declined intervention. On presentation to our institution 7 years later, the lesion had enlarged significantly, and the patient consented to excision. At surgery, an 8 × 6.5 × 4.8 cm intracardiac mass located on the inferior heart border was excised with an intact capsule through a median sternotomy approach. The patient had an uneventful postoperative course. We discuss the diagnostic workup, treatment, and characteristics of this rare cardiac tumor. PMID:26140782

  14. Cardiac Syndrome X: Update.

    PubMed

    Agrawal, Shilpa; Mehta, Puja K; Bairey Merz, C Noel

    2016-01-01

    Cardiac Syndrome X (CSX), characterized by angina-like chest discomfort, ST segment depression during exercise, and normal epicardial coronary arteries at angiography, is highly prevalent in women. CSX is not benign, and linked to adverse cardiovascular outcomes and a poor quality of life. Coronary microvascular and endothelial dysfunction and abnormal cardiac nociception have been implicated in the pathogenesis of CSX. Treatment includes life-style modification, anti-anginal, anti-atherosclerotic, and anti-ischemic medications. Non-pharmacological options include cognitive behavioral therapy, enhanced external counterpulsation, neurostimulation, and stellate ganglionectomy. Studies have shown the efficacy of individual treatments but guidelines outlining the best course of therapy are lacking. PMID:26567981

  15. Cardiac disease in pregnancy

    PubMed Central

    Nqayana, T; Moodley, J; Naidoo, DP

    2008-01-01

    Summary Summary This study was a retrospective review of patient charts of a relatively large number of patients with cardiac disease in pregnancy in a developing country. Ninety-five patients were evaluated; the majority (n = 36) were in the age group 21?25 years. Rheumatic heart disease was the commonest aetiology; eight women required balloon mitral valvuloplasty and one had a valve replacement at 32 weeks’ gestation. There were no maternal deaths but morbidity was high; 13 patients were admitted in cardiac failure, nine had atrial fibrillation and three required intensive-care management. There were 86 live births of the 97 deliveries. PMID:18568175

  16. Endogenous cardiac stem cells.

    PubMed

    Barile, Lucio; Messina, Elisa; Giacomello, Alessandro; Marbán, Eduardo

    2007-01-01

    In the past few years it has been established that the heart contains a reservoir of stem and progenitor cells. These cells are positive for various stem/progenitor cell markers (Kit, Sca-1, Isl-1, and Side Population (SP) properties). The relationship between the various cardiac stem cells (CSC) and progenitor cells described awaits clarification. Furthermore, they may open a new therapeutic strategies of cardiac repair based on the regeneration potential of cardiac stem cells. Currently, cellular cardiomyoplasty is actively explored as means of regenerating damaged myocardium using several different cell types. CSCs seem a logical cell source to exploit for cardiac regeneration therapy. Their presence into the heart, the frequent co-expression of early cardiac progenitor transcription factors, and the capability for ex vivo and in vivo differentiation toward the cardiac lineages offer promise of enhanced cardiogenicity compared to other cell sources. CSCs, when isolated from various animal models by selection based on c-Kit, Sca-1, and/or MDR1, have shown cardiac regeneration potential in vivo following injection in the infracted myocardium. Recently, we have successfully isolated CSCs from small biopsies of human myocardium and expanded them ex vivo by many folds without losing differentiation potential into cardiomyocytes and vascular cells, bringing autologous transplantation of CSCs closer to clinical evaluation. These cells are spontaneously shed from human surgical specimens and murine heart samples in primary culture. This heterogeneous population of cells forms multi-cellular clusters, dubbed cardiospheres (CSs), in suspension culture. CSs are composed of clonally-derived cells, consist of proliferating c-Kit positive cells primarily in their core and differentiating cells expressing cardiac and endothelial cell markers on their periphery. Although the intracardiac origin of adult myocytes has been unequivocally documented, the potential of an extracardiac source of cells, able to repopulate the lost CSCs in pathological conditions (infarct) cannot be excluded and will be discussed in this review. The delivery of human CSs or of CSs-derived cells into the injured heart of the SCID mouse resulted in engraftment, migration, myocardial regeneration and improvement of left ventricular function. Our method for ex vivo expansion of resident CSCs for subsequent autologous transplantation back into the heart, may give these cell populations, the resident and the transplanted one, the combined ability to mediate myocardial regeneration to an appreciable degree, and may change the way in which cardiovascular disease will be approached in the future. PMID:17631436

  17. Cardiac stem cells: isolation, expansion and experimental use for myocardial regeneration.

    PubMed

    Barile, Lucio; Chimenti, Isotta; Gaetani, Roberto; Forte, Elvira; Miraldi, Fabio; Frati, Giacomo; Messina, Elisa; Giacomello, Alessandro

    2007-02-01

    Cellular cardiomyoplasty (myogenic cell grafting) is actively being explored as a novel method to regenerate damaged myocardium. The adult human heart contains small populations of indigenous committed cardiac stem cells or multipotent cardiac progenitor cells, identified by their cell-surface expression of c-kit (the receptor for stem cell factor), P-glycoprotein (a member of the multidrug resistance protein family), and Sca-1 (stem cell antigen 1, a mouse hematopoietic stem cell marker) or a Sca-1-like protein. Cardiac stem cells represent a logical source to exploit in cardiac regeneration therapy because, unlike other adult stem cells, they are likely to be intrinsically programmed to generate cardiac tissue in vitro and to increase cardiac tissue viability in vitro. Cardiac stem cell therapy could, therefore, change the fundamental approach to the treatment of heart disease. PMID:17230222

  18. Does removal of deep breathing exercises from a physiotherapy program including pre-operative education and early mobilisation after cardiac surgery alter patient outcomes?

    PubMed

    Brasher, Phillip A; McClelland, Kirstin H; Denehy, Linda; Story, Ian

    2003-01-01

    The aim of this study was to establish whether removal of breathing exercises from a regimen including early mobilisation changes the incidence of post-operative pulmonary complications for patients after cardiac surgery. Two hundred and thirty patients undergoing open heart surgery at Monash Medical Centre, Melbourne, were enrolled in this randomised controlled trial. All patients received physiotherapy treatment pre-operatively and post-operatively for three days. Patients were mobilised as soon as possible after surgery. Breathing group (control) patients performed a set routine of deep breathing exercises at each physiotherapy visit while those in the intervention group did not perform this routine. Other than the breathing exercises, patient management was similar between groups in terms of assessment, positioning and mobility. The incidence of postoperative pulmonary complications, post-operative length of stay, oxyhaemoglobin saturation and pulmonary function were measured pre-operatively and post-operatively. Intention-to-treat analysis was performed for post-operative pulmonary complications and length of stay. Other data were analysed using t-tests, chi square and repeated measures analysis of variance. There were no significant differences between the groups in the primary dependent variables. It is concluded that removal of breathing exercises from the routine physiotherapy management of open heart surgery patients does not significantly alter patient outcome. PMID:12952516

  19. Simple, rapid /sup 125/I-labeled cyclosporine double antibody/polyethylene glycol radioimmunoassay used in a pediatric cardiac transplant program

    SciTech Connect

    Berk, L.S.; Webb, G.; Imperio, N.C.; Nehlsen-Cannarella, S.L.; Eby, W.C.

    1986-01-01

    We modified the Sandoz cyclosporine radioimmunoassay because of our need for frequent clinical monitoring of cyclosporine drug levels in allo- and xenograft pediatric cardiac transplant patients. With application of a commercially available (/sup 125/I)cyclosporine label in place of (/sup 3/H)cyclosporine and a second antibody/polyethylene glycol (PEG) method of separation in place of charcoal separation, we simplified and enhanced the speed and precision of assay performance. Studies of 140 whole blood samples comparing this new method to the (/sup 3/H)cyclosporine radioimmunoassay (RIA) method of Berk and colleagues yielded a coefficient of correlation of 0.96 (p less than 0.00001) with means of 626 and 667 ng/ml for (/sup 3/H)RIA and (/sup 125/I)RIA, respectively, and a regression equation of y = 28 + 1.02x. The major advantages are that total assay time is reduced to approximately 1 h; (/sup 125/I)cyclosporine label is used, avoiding the problems associated with liquid scintillation counting; and precision is enhanced by separating bound and free fractions with second antibody/PEG. These modifications should provide for greater ease of assay performance and improved clinical utility of cyclosporine monitoring not only in the pediatric but also in the adult transplant patient.

  20. Glial fibrillary acidic protein (GFAP) shows circadian oscillations in crayfish Procambarus clarkii putative pacemakers.

    PubMed

    Rodríguez-Muñoz, María de la Paz; Escamilla-Chimal, Elsa G

    2015-10-01

    Although several studies of glia have examined glial fibrillary acid protein (GFAP) and its relationship to the circadian rhythms of different organisms, they have not explored the daily GFAP oscillations in the putative pacemakers of the crayfish Procambarus clarkii or in other crustaceans. In this study we investigated the daily variations in GFAP concentrations in the eyestalk and brain, which are considered to be putative pacemakers in adult P. clarkii. In both structures, the glial GFAP was quantified using the indirect enzyme-linked immunosorbent assay (ELISA), and double labeling immunofluorescence was used to detect it and its co-localization with protein Period (PER), an important component of the circadian clock, in various regions of both structures. The ELISA results were analyzed using Cosinor and one-way ANOVA with Bonferroni and Scheffé's post hoc tests. The results of this analysis showed that the GFAP levels present circadian oscillations in both structures. Moreover, GFAP was localized in different structures of the eyestalk and brain; however, co-localization with PER occurred only in the lamina ganglionaris, specifically in the cartridges of the eyestalk and in some of the cluster 9 brain cells. These results suggest that as in other invertebrates and vertebrates, glial cells could be involved in the circadian system of P. clarkii; however, thus far we cannot know whether the glial cells are only effectors, participate in afferent pathways, or are part of the circadian clock. PMID:26362020

  1. Pacemaker infections. A 2-year follow-up of antibiotic prophylaxis.

    PubMed

    Bluhm, G L

    1985-01-01

    To evaluate the long-term effect of systemic antibiotic prophylaxis at pacemaker surgery, an analysis was made of infections in 272 patients submitted to 303 consecutive pacemaker operations. The follow-up time was 24-33 months. Antibiotic prophylaxis had been given in all cases. The overall infection rate was 4.0%: The incidence after new implant was 3.8%, generator replacement 2.4%, electrode replacement 15% and early reoperation 4.2%, with the only statistically significant difference between electrode replacement and generator replacement. The interval between operation and appearance of infection was 3 days to 18 months. The causal microorganisms were methicillin-resistant Staphylococcus epidermidis in four patients, methicillin-sensitive S. epidermis in one patient and methicillin-sensitive S. aureus in three. An anaerobic gram-positive coccus was cultured in one patient and a nonenteric gram-negative rod in another. Five infections were cured by antibiotic treatment alone, but in seven cases surgery was also needed. The incidence of infection was significantly increased when potential predisposing factors--diabetes mellitus, postoperative hematoma and use of a temporary electrode--were present. PMID:4081673

  2. Does adrenaline modulate the Na+-Ca2+ exchanger in isolated toad pacemaker cells?

    PubMed

    Ju, Y K; Allen, D G

    1999-08-01

    beta-Adrenergic stimulation of pacemaker cells from the sinus venosus of the cane toad (Bufo marinus) increases intracellular calcium ([Ca2+]i) and firing rate. The increase in [Ca2+]i could contribute to the increased firing rate by increasing the inward Na+-Ca2+ exchange current (INa-Ca) during diastole. In this study we measured [Ca2+]i and membrane currents in single, isolated, voltage-clamped pacemaker cells. We show that INa-Ca increases during beta-adrenergic stimulation. To test whether this increase in INa-Ca is caused by elevated [Ca2+]i or by changes in the properties of the Na+-Ca2+ exchanger, we made rapid applications of caffeine and plotted the INa-Ca against [Ca2+]i. This relationship was linear during the declining phase of the [Ca2+]i signal caused by caffeine and was not significantly different in the presence or absence of beta stimulation. These results show that INa-Ca is increased during beta-adrenergic stimulation and will contribute to the increased firing rate. However the increase in INa-Ca appears to be a consequence of the increase in [Ca2+]i and is not caused by changes in the intrinsic properties of the Na+-Ca2+ exchanger. PMID:10398864

  3. Responses of a bursting pacemaker to excitation reveal spatial segregation between bursting and spiking mechanisms

    PubMed Central

    Maran, Selva K; Sieling, Fred H; Demla, Kavita; Prinz, Astrid A; Canavier, Carmen C

    2011-01-01

    Central pattern generators (CPGs) frequently include bursting neurons that serve as pacemakers for rhythm generation. Phase resetting curves (PRCs) can provide insight into mechanisms underlying phase locking in such circuits. PRCs were constructed for a pacemaker bursting complex in the pyloric circuit in the stomatogastric ganglion of the lobster and crab. This complex is comprised of the Anterior Burster (AB) neuron and two Pyloric Dilator (PD) neurons that are all electrically coupled. Artificial excitatory synaptic conductance pulses of different strengths and durations were injected into one of the AB or PD somata using the Dynamic Clamp. Previously, we characterized the inhibitory PRCs by assuming a single slow process that enabled synaptic inputs to trigger switches between an up state in which spiking occurs and a down state in which it does not. Excitation produced five different PRC shapes, which could not be explained with such a simple model. A separate dendritic compartment was required to separate the mechanism that generates the up and down phases of the bursting envelope (1) from synaptic inputs applied at the soma, (2) from axonal spike generation and (3) from a slow process with a slower time scale than burst generation. This study reveals that due to the nonlinear properties and compartmentalization of ionic channels, the response to excitation is more complex than inhibition. PMID:21360137

  4. Time and memory: towards a pacemaker-free theory of interval timing.

    PubMed Central

    Staddon, J E; Higa, J J

    1999-01-01

    A popular view of interval timing in animals is that it is driven by a discrete pacemaker-accumulator mechanism that yields a linear scale for encoded time. But these mechanisms are fundamentally at odds with the Weber law property of interval timing, and experiments that support linear encoded time can be interpreted in other ways. We argue that the dominant pacemaker-accumulator theory, scalar expectancy theory (SET), fails to explain some basic properties of operant behavior on interval-timing procedures and can only accommodate a number of discrepancies by modifications and elaborations that raise questions about the entire theory. We propose an alternative that is based on principles of memory dynamics derived from the multiple-time-scale (MTS) model of habituation. The MTS timing model can account for data from a wide variety of time-related experiments: proportional and Weber law temporal discrimination, transient as well as persistent effects of reinforcement omission and reinforcement magnitude, bisection, the discrimination of relative as well as absolute duration, and the choose-short effect and its analogue in number-discrimination experiments. Resemblances between timing and counting are an automatic consequence of the model. We also argue that the transient and persistent effects of drugs on time estimates can be interpreted as well within MTS theory as in SET. Recent real-time physiological data conform in surprising detail to the assumptions of the MTS habituation model. Comparisons between the two views suggest a number of novel experiments. PMID:10220931

  5. Advanced Cardiac Life Support.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document contains materials for an advanced college course in cardiac life support developed for the State of Iowa. The course syllabus lists the course title, hours, number, description, prerequisites, learning activities, instructional units, required text, six references, evaluation criteria, course objectives by units, course…

  6. Cardiac Resynchronization Therapy: How to Decrease Nonresponders.

    PubMed

    Tolosana, José María; Mont, Lluís

    2015-12-01

    Nonresponse to cardiac resynchronization therapy (CRT) is still a major issue in therapy expansion. The description of fast, simple, cost-effective methods to optimize CRT could help in adapting pacing intervals to individual patients. A better understanding of the importance of appropriate patient selection, left ventricular lead placement, and device programming, together with a multidisciplinary approach and an optimal follow-up of the patients, may reduce the percentage of nonresponders. PMID:26596820

  7. Attitudes of Implanting Physicians about Cardiac Rhythm Management Devices and Their Features

    PubMed Central

    Elmouchi, Darryl A.; Chalfoun, Nagib; Gauri, Andre

    2013-01-01

    Modern cardiac rhythm management systems have become increasingly complex. The decision on which specific system to implant in a given patient often rests with the implanting physician. We conducted a multiple-choice survey to assess the opinions and preferences of cardiologists and electrophysiologists who implant and follow cardiac rhythm management systems. Reliability and battery longevity were viewed as the most important characteristics in device selection. Patient characteristics which most affected device choice were pacing indication and life expectancy. Remote technology was used in 47% of pacemaker patients, 64% of ICD patients, and 65% of CRT-D patients, with wireless (radiofrequency) remote patient monitoring associated with higher patient compliance rates (74% versus 64%, resp.). Wireless remote patient management with alerts for atrial tachyarrhythmias was felt to be important by 76% of respondents. When choosing an MR-conditional device, physicians deemed patients with prior orthopedic problems, a history of cancer, or neurological disorders to be more likely to require a future MRI. Device longevity and reliability remain the most important factors which influence device selection. Wireless remote patient monitoring with alerts is considered increasingly important when choosing a specific cardiac rhythm management system to implant. PMID:24490084

  8. Cell and gene therapy for arrhythmias: Repair of cardiac conduction damage

    PubMed Central

    Xiao, Yong-Fu

    2011-01-01

    Action potentials generated in the sinoatrial node (SAN) dominate the rhythm and rate of a healthy human heart. Subsequently, these action potentials propagate to the whole heart via its conduction system. Abnormalities of impulse generation and/or propagation in a heart can cause arrhythmias. For example, SAN dysfunction or conduction block of the atrioventricular node can lead to serious bradycardia which is currently treated with an implanted electronic pacemaker. On the other hand, conduction damage may cause reentrant tachyarrhythmias which are primarily treated pharmacologically or by medical device-based therapies, including defibrillation and tissue ablation. However, drug therapies sometimes may not be effective or are associated with serious side effects. Device-based therapies for cardiac arrhythmias, even with well developed technology, still face inadequacies, limitations, hardware complications, and other challenges. Therefore, scientists are actively seeking other alternatives for antiarrhythmic therapy. In particular, cells and genes used for repairing cardiac conduction damage/defect have been investigated in various studies both in vitro and in vivo. Despite the complexities of the excitation and conduction systems of the heart, cell and gene-based strategies provide novel alternatives for treatment or cure of cardiac arrhythmias. This review summarizes some highlights of recent research progress in this field. PMID:22783301

  9. Distal balloon occlusion allows epicardial lead placement in a tortuous branch of the great cardiac vein.

    PubMed

    Patel, Parag; Banchs, Javier E; Stevenson, Robert T; Patel, Nehal D; Naccarelli, Gerald V; Wolbrette, Deborah L; Samii, Soraya M; Penny-Peterson, Erica D; Gonzalez, Mario D

    2009-08-01

    Cardiac resynchronization therapy (CRT) is a well established treatment modality in heart failure. Using standard techniques, placement of the left ventricular (LV) lead is usually successful; however LV lead placement failure remains a clinical problem. In the present report, the standard over-the-wire technique was not successful due to absence of the necessary support to place the lead into a tortuous vein. This was achieved using balloon occlusion of the great cardiac vein distal to the target vessel. An 81 year old female candidate for CRT presented for biventricular pacemaker implantation. After placement of the right ventricular lead, the CS was cannulated and an occlusive venogram was performed. A lateral branch was selected as the target vessel. Initial attempts at cannulating the vessel were unsuccessful due to the guidewire and telescoping delivery system prolapsing into the great cardiac vein. The acute angle prevented instrumentation of the branch with the tools available. A second parallel CS sheath was advanced to drive a balloon catheter used to occlude the great cardiac vein distal to the target vessel. This provided support for the guidewire and lead allowing their advancement through the tortuous vessel. Consecutive traction on the balloon during also helped to reflect the lead towards the vessel. The lead remained stable in its final position on the lateral wall of the LV with appropriate thresholds and no diaphragmatic stimulation. We report a case where balloon occlusion of the great cardiac vein distal to the target branch aided in advancing the LV lead into the desired position. This approach can be used in navigating lead placement to branches thought to be unreachable. Techniques such as this can decrease the failure rate of CRT implants. PMID:19184387

  10. Erbb2 Is Required for Cardiac Atrial Electrical Activity during Development

    PubMed Central

    Tenin, Gennadiy; Clowes, Christopher; Wolton, Kathryn; Krejci, Eliska; Wright, Jayne A.; Lovell, Simon C.; Sedmera, David; Hentges, Kathryn E.

    2014-01-01

    The heart is the first organ required to function during embryonic development and is absolutely necessary for embryo survival. Cardiac activity is dependent on both the sinoatrial node (SAN), which is the pacemaker of heart's electrical activity, and the cardiac conduction system which transduces the electrical signal though the heart tissue, leading to heart muscle contractions. Defects in the development of cardiac electrical function may lead to severe heart disorders. The Erbb2 (Epidermal Growth Factor Receptor 2) gene encodes a member of the EGF receptor family of receptor tyrosine kinases. The Erbb2 receptor lacks ligand-binding activity but forms heterodimers with other EGF receptors, stabilising their ligand binding and enhancing kinase-mediated activation of downstream signalling pathways. Erbb2 is absolutely necessary in normal embryonic development and homozygous mouse knock-out Erbb2 embryos die at embryonic day (E)10.5 due to severe cardiac defects. We have isolated a mouse line, l11Jus8, from a random chemical mutagenesis screen, which carries a hypomorphic missense mutation in the Erbb2 gene. Homozygous mutant embryos exhibit embryonic lethality by E12.5-13. The l11Jus8 mutants display cardiac haemorrhage and a failure of atrial function due to defects in atrial electrical signal propagation, leading to an atrial-specific conduction block, which does not affect ventricular conduction. The l11Jus8 mutant phenotype is distinct from those reported for Erbb2 knockout mouse mutants. Thus, the l11Jus8 mouse reveals a novel function of Erbb2 during atrial conduction system development, which when disrupted causes death at mid-gestation. PMID:25269082

  11. Video-assisted thoracoscopic implantation of a diaphragmatic pacemaker in a child with tetraplegia: indications, technique, and results*

    PubMed Central

    Pinto, Darcy Ribeiro; Tedde, Miguel Lia; Avino, Alexandre José Gonçalves; Brandão, Suzan Lúcia Brancher; Zanatta, Iuri; Hahn, Rafael

    2015-01-01

    We report the case of a child with tetraplegia after cervical trauma, who subsequently underwent diaphragmatic pacemaker implantation. We reviewed the major indications for diaphragmatic pacing and the types of devices employed. We highlight the unequivocal benefit of diaphragmatic pacing in the social and educational reintegration of individuals with tetraplegia. PMID:25750678

  12. Video-assisted thoracoscopic implantation of a diaphragmatic pacemaker in a child with tetraplegia: indications, technique, and results.

    PubMed

    Filho Pinto, Darcy Ribeiro; Tedde, Miguel Lia; Avino, Alexandre José Gonçalves; Brandão, Suzan Lúcia Brancher; Zanatta, Iuri; Hahn, Rafael

    2015-01-01

    We report the case of a child with tetraplegia after cervical trauma, who subsequently underwent diaphragmatic pacemaker implantation. We reviewed the major indications for diaphragmatic pacing and the types of devices employed. We highlight the unequivocal benefit of diaphragmatic pacing in the social and educational reintegration of individuals with tetraplegia. PMID:25750678

  13. The role of Period1 in non-photic resetting of the hamster circadian pacemaker in the suprachiasmatic nucleus

    E-print Network

    Silver, Rae

    The role of Period1 in non-photic resetting of the hamster circadian pacemaker consistent with the non- photic phase response curve. Adult male hamsters (Mesocricetus auratus) obtained sacrificed. In this case, hamsters transferred to DD were placed in cages equipped with running wheels

  14. Self-Organized Pacemakers in a Coupled Reaction-Diffusion-Mechanics System A. V. Panfilov and R. H. Keldermann

    E-print Network

    Utrecht, Universiteit

    ], which in turn affects the spiral wave dynamics [6]. Furthermore, a ``chain reaction'' of spiral waveSelf-Organized Pacemakers in a Coupled Reaction-Diffusion-Mechanics System A. V. Panfilov and R. H of a coupled reaction-diffusion-mechanics system, we find that me- chanical deformation can induce automatic

  15. Slow progressing cardiac complications—a case report

    PubMed Central

    Williams, Jonathan C.; Elkington, William C.

    2008-01-01

    Abstract Objective This case presentation describes an uncommon development of complete heart block. Within 48 hours after a motor vehicle accident with the deployment of the air bag against the patient's chest, the patient reported exertional bradycardia and shortness of breath. Clinical Features A 51-year-old man was in a motor vehicle accident. After the collision, he noticed a slow onset of chest discomfort with exertion and bradycardia. The patient experienced cardiac difficulty during a stress electrocardiogram. During the 4 months after the motor vehicle accident, symptoms progressed; and a diagnosis of vagal sympathetic reflex was suggested. Intervention and Outcome A pacemaker was finally required because of the ventricular pacing of 35 to 40 beats per minute, which was symptomatic of a complete atrioventricular block. Conclusion A gradual progression to complete atrioventricular block over a period longer than 3 weeks is unusual. This case demonstrates that a patient manifesting exertional bradycardia and shortness of breath shortly after chest trauma should be regularly monitored until all symptoms are resolved. PMID:19674717

  16. The Physics of Cardiac Fibrillation: Strings that kill

    NASA Astrophysics Data System (ADS)

    Bodenschatz, Eberhard

    2009-03-01

    Fibrillation is a state of spatio-temporal chaos in a 3d-biological excitable medium, namely the heart muscle. The building blocks are wave-emitting three-dimensional topological singularities in the electric excitation field of the tissue. These string like singularities send out a rotating wave fields with very fast frequencies (up to 10 times normal heart rate) and thus dominate over the pacemaker. The incoherent electrical excitation of the spatio-temporal chaotic dynamics leads to an unsynchronized contraction of the cardiac muscle and to the loss of the pumping action, and if untreated to death. Due to the topological nature of the spatio-temporal chaotic state it is very difficult to control. Current defibrillation technologies use strong electric field pulses (1 kV, 30 A, 12 ms) to reset the whole muscle. Here we report that natural muscle heterogeneities act as wave emitting sites when a weak electric field pulse is applied across the tissue. We report theoretical predictions on the physics and support the findings by results from experiment. This work was conducted in collaboration with Stefan Luther (MPIDS), Falvio Fenton ( Cornell), Amgad Squires (Cornell), Robert Gilmour (Cornell), Valentin Krinsky (MPIDS), Alain Pumir (NIce).

  17. [Cardiac auscultation in children].

    PubMed

    Ratti, Carlo; Grassi, Laura; De Maria, Elia; Bonetti, Lorenzo; Borghi, Adriana; Cappelli, Stefano

    2014-12-01

    Cardiac auscultation permits to distinguish between the innocent heart murmurs and pathologic murmurs; characteristics of pathologic murmurs include a holosystolic or diastolic murmur, maximal murmur intensity at the upper left sternal border and increased intensity when the patient stands. Murmurs should be described by their timing in the cardiac cycle, intensity, shape, pitch, location, radiation, and response to dynamic maneuvers. When the medical history and physical examination support the diagnosis of innocent heart murmur, neither further investigation nor referal is indicated. On the contrary, echocardiography is recommended for patients with any other abnormal physical examination findings that increase the likelihood of structural heart disease. In this review we discuss the definition and classification of murmurs, how to evaluate it. PMID:25533235

  18. Cardiac outflow tract anomalies.

    PubMed

    Neeb, Zachary; Lajiness, Jacquelyn D; Bolanis, Esther; Conway, Simon J

    2013-07-01

    The mature outflow tract (OFT) is, in basic terms, a short conduit. It is a simple, although vital, connection situated between contracting muscular heart chambers and a vast embryonic vascular network. Unfortunately, it is also a focal point underlying many multifactorial congenital heart defects (CHDs). Through the use of various animal models combined with human genetic investigations, we are beginning to comprehend the molecular and cellular framework that controls OFT morphogenesis. Clear roles of neural crest cells (NCC) and second heart field (SHF) derivatives have been established during OFT formation and remodeling. The challenge now is to determine how the SHF and cardiac NCC interact, the complex reciprocal signaling that appears to be occurring at various stages of OFT morphogenesis, and finally how endocardial progenitors and primary heart field (PHF) communicate with both these colonizing extra-cardiac lineages. Although we are beginning to understand that this dance of progenitor populations is wonderfully intricate, the underlying pathogenesis and the spatiotemporal cell lineage interactions remain to be fully elucidated. What is now clear is that OFT alignment and septation are independent processes, invested via separate SHF and cardiac neural crest (CNC) lineages. This review will focus on our current understanding of the respective contributions of the SHF and CNC lineage during OFT development and pathogenesis. PMID:24014420

  19. Cardiac surgery for arrhythmias.

    PubMed

    Cox, James L

    2004-02-01

    Cardiac arrhythmia surgery was initiated in 1968 with the first successful division of an accessory AV connection for the Wolff-Parkinson-White Syndrome. Subsequent surgical procedures included the left atrial isolation procedure and the right atrial isolation procedure for automatic atrial tachycardias, discrete cryosurgery of the AV node for AV nodal reentry tachycardia, the atrial transection procedure, corridor procedure and Maze procedure for atrial fibrillation, the right ventricular disconnection procedure for arrhythmogenic right ventricular tachycardia, the encircling endocardial ventriculotomy, subendocardial resection procedure, endocardial cryoablation, the Jatene procedure, and the Dor procedure for ischemic ventricular tachycardia. Because of monumental strides in the treatment of most refractory arrhythmias by endocardial catheter techniques during the past decade, the only remaining viable surgical procedures for cardiac arrhythmias are the Maze procedure for atrial fibrillation and the Dor procedure for ischemic ventricular tachycardia. Nevertheless, the 25-30 years of intense activity in the field of cardiac arrhythmia surgery provided the essential foundation for the development of these catheter techniques and represent one of the most exciting and productive eras in the history of medicine. In one short professional career, we have witnessed the birth of arrhythmia surgery, its adolescence as an "esoteric" specialty, its prime as an enlightening yet exhausting period, and finally its waning years as a source of knowledge and wisdom on which better methods of treatment have been founded. One could hardly ask for a more rewarding experience. PMID:14764186

  20. Cardiac surgery for arrhythmias.

    PubMed

    Cox, James L

    2004-02-01

    Cardiac arrhythmia surgery was initiated in 1968 with the first successful division of an accessory AV connection for the Wolff-Parkinson-White syndrome. Subsequent surgical procedures included the left atrial isolation procedure and right atrial isolation procedure for automatic atrial tachycardias, discrete cryosurgery of the AV node for AV nodal reentrant tachycardia, the atrial transection procedure, the corridor procedure, and the maze procedure for atrial fibrillation, the right ventricular disconnection procedure for arrhythmogenic right ventricular tachycardia, and the encircling endocardial ventriculotomy, subendocardial resection procedure, endocardial cryoablation, the Jatene procedure, and the Dor procedure for ischemic ventricular tachycardia. Because of monumental strides in the treatment of most refractory arrhythmias by endocardial catheter techniques during the past decade, the only remaining viable surgical procedures for cardiac arrhythmias are the maze procedure for atrial fibrillation and the Dor procedure for ischemic ventricular tachycardia. Nevertheless, the 25 to 30 years of intense activity in the field of cardiac arrhythmia surgery provided the essential foundation for the development of these catheter techniques and represent one of the most exciting and productive eras in the history of medicine. In one short professional career, we have witnessed the birth of arrhythmia surgery, its adolescence as an "esoteric" specialty, its prime as an enlightening yet exhausting period, and finally its waning years as a source of knowledge and wisdom upon which better methods of treatment have been founded. One could hardly ask for a more rewarding experience. PMID:15028063

  1. Cardiac surgery for arrhythmias.

    PubMed

    Cox, James L

    2004-11-01

    Cardiac arrhythmia surgery was initiated in 1968 with the first successful division of an accessory AV connection for the Wolff-Parkinson-White Syndrome. Subsequent surgical procedures included the left atrial isolation procedure and the right atrial isolation procedure for automatic atrial tachycardias, discrete cryosurgery of the AV node for AV nodal reentry tachycardia, the atrial transection procedure, corridor procedure and Maze procedure for atrial fibrillation, the right ventricular disconnection procedure for arrhythmogenic right ventricular tachycardia, the encircling endocardial ventriculotomy, subendocardial resection procedure, endocardial cryoablation, the Jatene procedure, and the Dor procedure for ischemic ventricular tachycardia. Because of monumental strides in the treatment of most refractory arrhythmias by endocardial catheter techniques during the past decade, the only remaining viable surgical procedures for cardiac arrhythmias are the Maze procedure for atrial fibrillation and the Dor procedure for ischemic ventricular tachycardia. Nevertheless, the 25-30 years of intense activity in the field of cardiac arrhythmia surgery provided the essential foundation for the development of these catheter techniques and represent one of the most exciting and productive eras in the history of medicine. In one short professional career, we have witnessed the birth of arrhythmia surgery, its adolescence as an "esoteric" specialty, its prime as an enlightening yet exhausting period, and finally its waning years as a source of knowledge and wisdom on which better methods of treatment have been founded. One could hardly ask for a more rewarding experience. PMID:23570110

  2. Cardiac emergencies in children.

    PubMed

    Schamberger, M S

    1996-06-01

    Pediatric cardiac emergencies require very specific treatment in the emergency room setting. Considering the possibility of a cardiac problem as the cause for the presenting symptoms is the initial step in successful management. Many patients present with what is initially considered a primary pulmonary disorder such as pneumonia, asthma, or bronchiolitis. Airway stabilization and ventilatory support, if needed, remain the first steps in stabilizing the patient. Many neonates with acutely decompensating heart disease may require the patency of the ductus arteriosus for survival. Prostaglandin E given as continuous infusion is the treatment of choice. Congestive heart failure can present at any age. In older patients, it is often due to myocarditis and is characterized by low cardiac output. Supportive measures, fluid restriction, and inotropic support are the basic concepts for initial treatment. Supraventricular tachycardia is a frequent arrhythmia, especially in young children. If the patient is unstable, immediate intravenous administration of adenosine or synchronized cardioversion are the initial interventions. In stable patients, vagal maneuvers may be attempted to abort the arrhythmia. PMID:8793920

  3. Cardiac Signatures of Personality

    PubMed Central

    Koelsch, Stefan; Enge, Juliane; Jentschke, Sebastian

    2012-01-01

    Background There are well-established relations between personality and the heart, as evidenced by associations between negative emotions on the one hand, and coronary heart disease or chronic heart failure on the other. However, there are substantial gaps in our knowledge about relations between the heart and personality in healthy individuals. Here, we investigated whether amplitude patterns of the electrocardiogram (ECG) correlate with neurotisicm, extraversion, agreeableness, warmth, positive emotion, and tender-mindedness as measured with the Neuroticism-Extraversion-Openness (NEO) personality inventory. Specifically, we investigated (a) whether a cardiac amplitude measure that was previously reported to be related to flattened affectivity (referred to as values) would explain variance of NEO scores, and (b) whether correlations can be found between NEO scores and amplitudes of the ECG. Methodology/Principal Findings NEO scores and rest ECGs were obtained from 425 healthy individuals. Neuroticism and positive emotion significantly differed between individuals with high and low values. In addition, stepwise cross-validated regressions indicated correlations between ECG amplitudes and (a) agreeableness, as well as (b) positive emotion. Conclusions/Significance These results are the first to demonstrate that ECG amplitude patterns provide information about the personality of an individual as measured with NEO personality scales and facets. These findings open new perspectives for a more efficient personality assessment using cardiac measures, as well as for more efficient risk-stratification and pre-clinical diagnosis of individuals at risk for cardiac, affective and psychosomatic disorders. PMID:22363649

  4. Cardiac surgery 2014 reviewed.

    PubMed

    Doenst, Torsten; Strüning, Constanze; Moschovas, Alexandros; Gonzalez-Lopez, David; Valchanov, Ilija; Kirov, Hristo; Diab, Mahmoud; Faerber, Gloria

    2015-12-01

    For the year 2014, more than 17,000 published references can be found in Pubmed when entering the search term "cardiac surgery". The last year has been characterized by a vivid discussion in the fields where classic cardiac surgery and modern interventional techniques overlap. Specifically, there have been important contributions in the field of coronary revascularization with either percutaneous coronary intervention or bypass surgery as well as in the fields of interventional valve therapy. Here, the US core valve trial with the first demonstration of a survival advantage at 1 year with transcatheter valves compared to surgical aortic valve replacement or the 5-year outcome of the SYNTAX trial with significant advantages for bypass surgery has been the landmark. However, in addition to these most visible publications, there have been several highly relevant and interesting contributions. This review article will summarize the most pertinent publications in the fields of coronary revascularization, surgical treatment of valve disease, heart failure (i.e., transplantation and ventricular assist devices) and aortic surgery. This condensed summary will provide the reader with "solid ground" for up-to-date decision-making in cardiac surgery. PMID:26404007

  5. Nuclear imaging for cardiac amyloidosis.

    PubMed

    Noordzij, Walter; Glaudemans, Andor W J M; Longhi, Simone; Slart, Riemer H J A; Lorenzini, Massimiliano; Hazenberg, Bouke P C; Rapezzi, Claudio

    2015-03-01

    Histological analysis of endomyocardial tissue is still the gold standard for the diagnosis of cardiac amyloidosis, but has its limitations. Accordingly, there is a need for non-invasive modalities to diagnose cardiac amyloidosis. Echocardiography and ultrasound and magnetic resonance imaging can show characteristics which may not be very specific for cardiac amyloid. Nuclear medicine has gained a precise role in this context: several imaging modalities have become available for the diagnosis and prognostic stratification of cardiac amyloidosis during the last two decades. The different classes of radiopharmaceuticals have the potential to bind different constituents of the amyloidotic infiltrates, with some relevant differences among the various aetiologic types of amyloidosis and the different organs and tissues involved. This review focuses on the background of the commonly used modalities, their present clinical applications, and future clinical perspectives in imaging patients with (suspected) cardiac amyloidosis. The main focus is on conventional nuclear medicine (bone scintigraphy, cardiac sympathetic innervation) and positron emission tomography. PMID:25424887

  6. Sudden cardiac death and obesity.

    PubMed

    Plourde, Benoit; Sarrazin, Jean-François; Nault, Isabelle; Poirier, Paul

    2014-09-01

    For individuals and the society as a whole, the increased risk of sudden cardiac death in obese patients is becoming a major challenge, especially since obesity prevalence has been increasing steadily around the globe. Traditional risk factors and obesity often coexist. Hypertension, diabetes, obstructive sleep apnea and metabolic syndrome are well-known risk factors for CV disease and are often present in the obese patient. Although the bulk of evidence is circumstantial, sudden cardiac death and obesity share common traditional CV risk factors. Structural, functional and metabolic factors modulate and influence the risk of sudden cardiac death in the obese population. Other risk factors such as left ventricular hypertrophy, increased number of premature ventricular complexes, altered QT interval and reduced heart rate variability are all documented in both obese and sudden cardiac death populations. The present review focuses on out-of-hospital sudden cardiac death and potential mechanisms leading to sudden cardiac death in this population. PMID:25160995

  7. Circadian rhythms in healthy aging--effects downstream from the pacemaker

    NASA Technical Reports Server (NTRS)

    Monk, T. H.; Kupfer, D. J.

    2000-01-01

    Using both previously published findings and entirely new data, we present evidence in support of the argument that the circadian dysfunction of advancing age in the healthy human is primarily one of failing to transduce the circadian signal from the circadian timing system (CTS) to rhythms "downstream" from the pacemaker rather than one of failing to generate the circadian signal itself. Two downstream rhythms are considered: subjective alertness and objective performance. For subjective alertness, we show that in both normal nychthemeral (24 h routine, sleeping at night) and unmasking (36 h of constant wakeful bed rest) conditions, advancing age, especially in men, leads to flattening of subjective alertness rhythms, even when circadian temperature rhythms are relatively robust. For objective performance, an unmasking experiment involving manual dexterity, visual search, and visual vigilance tasks was used to demonstrate that the relationship between temperature and performance is strong in the young, but not in older subjects (and especially not in older men).

  8. Stability, precision, and near-24-hour period of the human circadian pacemaker

    NASA Technical Reports Server (NTRS)

    Czeisler, C. A.; Duffy, J. F.; Shanahan, T. L.; Brown, E. N.; Mitchell, J. F.; Rimmer, D. W.; Ronda, J. M.; Silva, E. J.; Allan, J. S.; Emens, J. S.; Dijk, D. J.; Kronauer, R. E.

    1999-01-01

    Regulation of circadian period in humans was thought to differ from that of other species, with the period of the activity rhythm reported to range from 13 to 65 hours (median 25.2 hours) and the period of the body temperature rhythm reported to average 25 hours in adulthood, and to shorten with age. However, those observations were based on studies of humans exposed to light levels sufficient to confound circadian period estimation. Precise estimation of the periods of the endogenous circadian rhythms of melatonin, core body temperature, and cortisol in healthy young and older individuals living in carefully controlled lighting conditions has now revealed that the intrinsic period of the human circadian pacemaker averages 24.18 hours in both age groups, with a tight distribution consistent with other species. These findings have important implications for understanding the pathophysiology of disrupted sleep in older people.

  9. Treatment of Congenital Complete Atrioventricular Heart Block With Permanent Epicardial Pacemaker in Neonatal Lupus Syndrome

    PubMed Central

    Tanriverdi, Sema; Ulger, Zulal; Siyah Bilgin, Betul; Kultursay, Nilgun; Yalaz, Mehmet; Atay, Yuksel; Koroglu, Ozge Altun

    2015-01-01

    Introduction: Neonatal lupus syndrome (NLS) is a passively acquired autoimmune condition due to the transplacental passage of maternal anti-Ro/SSA and anti-La/SSB antibodies in mothers with systemic lupus erythematosus (SLE), and congenital complete heart block (CHB) is its most serious manifestation. Skin and hepatic involvement may occur in later infancy. Case Presentation: A term infant with fetal bradycardia, detected at the 23rd gestational age, was diagnosed with CHB due to NLS and was successfully treated with a permanent epicardial pacemaker. The patient was reported here due to rarity of the procedure in neonatal period. Conclusions: Mothers with SLE should be screened and closely followed up during pregnancy for the development of fetal atrioventricular (AV) block. PMID:26473068

  10. [Sudden cardiac death in athletes].

    PubMed

    Parikka, Hannu

    2013-01-01

    Sudden deaths occurring during exercise are rare and are most commonly due to cardiac arrest. It is most commonly underlain by symptomless cardiomyopathy or coronary artery disease. Preventive work comes up against a diagnostic problem in distinguishing adaptational changes of the athletic heart from a heart disorder. To reveal the danger of cardiac arrest and reduce human tragedies international sports organizations and cardiologic expert groups recommend screening of cardiac disorders among competing athletes. PMID:24163971

  11. Role of mitochondria in contraction and pacemaking in the mouse uterus

    PubMed Central

    Gravina, FS; Parkington, HC; Kerr, KP; de Oliveira, RB; Jobling, P; Coleman, HA; Sandow, SL; Davies, MM; Imtiaz, MS; van Helden, DF

    2010-01-01

    BACKGROUND AND PURPOSE Uterine spontaneous contraction and pacemaking are poorly understood. This study investigates the role of the mitochondrial Ca2+ store in uterine activity. EXPERIMENTAL APPROACH We investigated the effects of mitochondrial and sarco-endoplasmic reticulum (SER) inhibitors on contraction, membrane potential (Vm) and cytosolic Ca2+ concentration ([Ca2+]c) in longitudinal smooth muscle of the mouse uterus. KEY RESULTS The mitochondrial agents rotenone, carbonylcyanide-3-chlorophenylhydrazone (CCCP), 7-chloro-5-(2-chlorophenyl)-1,5-dihydro-4,1-benzothiazepin-2(3H)-one (CGP37157) and kaempferol decreased the force of contractions. The ATP synthase inhibitor oligomycin had no significant effect. The effects of these agents were compared with those of SER inhibitors cyclopiazonic acid (CPA), 2-amino ethoxyphenylborate (2-APB) and caffeine. All agents, except CPA and oligomycin, decreased contractile force. CPA and CCCP transiently increased contraction frequency, which returned to control levels, whereas rotenone, CGP37157, kaempferol and 2-APB decreased frequency and caffeine had no significant effect. Application of the mitochondrial agents when CPA functionally inhibited stores did not change contraction frequency but, with the exception of kaempferol, decreased force. CCCP caused depolarization and maintained increase in [Ca2+]c or depolarization/transient hyperpolarization and transient increase in [Ca2+]c for oestrus and di-oestrus tissues respectively. Rotenone caused hyperpolarization and maintained increase in [Ca2+]c. CGP37157 and kaempferol caused hyperpolarization but no measurable change in [Ca2+]c. Application of a range of K+ channel blockers indicated a role of Ca2+-activated K+ (KCa) channels in the CCCP- and CGP37157-induced actions. CONCLUSIONS AND IMPLICATIONS Mitochondria have a modulatory role on uterine contractions, with mitochondrial inhibition reducing contraction amplitude and pacemaker frequency by changes in Vm, [Ca2+]c and/or Ca2+ influx. PMID:20942856

  12. Persistent sodium current drives conditional pacemaking in CA1 pyramidal neurons under muscarinic stimulation.

    PubMed

    Yamada-Hanff, Jason; Bean, Bruce P

    2013-09-18

    Hippocampal CA1 pyramidal neurons are normally quiescent but can fire spontaneously when stimulated by muscarinic agonists. In brain slice recordings from mouse CA1 pyramidal neurons, we examined the ionic basis of this activity using interleaved current-clamp and voltage-clamp experiments. Both in control and after muscarinic stimulation, the steady-state current-voltage curve was dominated by inward TTX-sensitive persistent sodium current (I(NaP)) that activated near -75 mV and increased steeply with depolarization. In control, total membrane current was net outward (hyperpolarizing) near -70 mV so that cells had a stable resting potential. Muscarinic stimulation activated a small nonselective cation current so that total membrane current near -70 mV shifted to become barely net inward (depolarizing). The small depolarization triggers regenerative activation of I(NaP), which then depolarizes the cell from -70 mV to spike threshold. We quantified the relative contributions of I(NaP), hyperpolarization-activated cation current (I(h)), and calcium current to pacemaking by using the cell's own firing as a voltage command along with specific blockers. TTX-sensitive sodium current was substantial throughout the entire interspike interval, increasing as the membrane potential approached threshold, while both Ih and calcium current were minimal. Thus, spontaneous activity is driven primarily by activation of I(NaP) in a positive feedback loop starting near -70 mV and providing increasing inward current to threshold. These results show that the pacemaking "engine" from I(NaP) is an inherent property of CA1 pyramidal neurons that can be engaged or disengaged by small shifts in net membrane current near -70 mV, as by muscarinic stimulation. PMID:24048831

  13. One-Year Follow-Up of Patients Undergoing Transvenous Extraction of Pacemaker and Defibrillator Leads

    PubMed Central

    Kempa, Maciej; Budrejko, Szymon; Piepiorka-Broniecka, Marta; Rogowski, Jan; Kozlowski, Dariusz; Raczak, Grzegorz

    2015-01-01

    Introduction The number of pacemaker and ICD implantations has increased substantially in the recent years. Therefore, complications are also observed in a greater number. In many cases, transvenous extraction of the previously implanted device (pacemaker or ICD) is the only solution. One may find in the literature information about the efficacy and safety of that procedure, but data concerning the results of long-term follow up are still limited. Aim The aim of the study was to assess the one-year mortality in the cohort of patients undergoing transvenous lead extraction procedures in our centre. Methods Records of the patients undergoing transvenous lead removal in the Department of Cardiology and Electrotherapy of the Medical University of Gda?sk were analyzed. We collected detailed information about 192 patients that had undergone the procedure from January 2003 until June 2012. Data were collected from medical and surgical records. We analyzed concomitant diseases, indications, and possible complications. Long-term follow-up data were gathered in the follow-up ambulatory records and over-the-phone interviews with patients or families. In several cases, we consulted the database of the Polish National Health Fund. Results During the early post-operative period 5 patients died, although none of those deaths was associated with the procedure itself. No other major complications were observed. During one-year follow-up other 5 patients died, which gave the overall one-year survival rate of 92.7%. Heart failure, renal failure and an infective indication showed significant association with increased mortality. Conclusion Results of transvenous lead extraction, a relatively safe procedure, should be assessed over time extending beyond the sole perioperative period. Some complications may be delayed in their nature, and may be observed only during the long-term follow up. PMID:26694032

  14. Registry of Unexplained Cardiac Arrest

    ClinicalTrials.gov

    2015-04-13

    Cardiac Arrest; Long QT Syndrome; Brugada Syndrome; Catecholaminergi Polymorphic Ventricular Tachycardia; Idiopathic VentricularFibrillation; Early Repolarization Syndrome; Arrhythmogenic Right Ventricular Cardiomyopathy

  15. Sudden cardiac death – Historical perspectives

    PubMed Central

    Abhilash, S.P.; Namboodiri, Narayanan

    2014-01-01

    Sudden cardiac death (SCD) is an unexpected death due to cardiac causes that occurs in a short time period (generally within 1 h of symptom onset) in a person with known or unknown cardiac disease. It is believed to be involved in nearly a quarter of human deaths, with ventricular fibrillation being the most common mechanism. It is estimated that more than 7 million lives per year are lost to SCD worldwide. Historical perspectives of SCD are analyzed with a brief description on how the developments in the management of sudden cardiac arrest evolved over time. PMID:24568828

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

    PubMed

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

    2015-05-01

    Remote monitoring (RM) of cardiac implantable electronic devices (CIEDs) permits early detection of arrhythmias, device, and lead failure and may also be useful in risk-predicting patient-related outcomes. Financial benefits for patients and healthcare organizations have also been shown. We sought to assess the implementation and funding of RM of CIEDs, including conventional pacemakers (PMs), implantable cardioverter defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices in Europe. Electronic survey from 43 centres in 15 European countries. In the study sample, RM was available in 22% of PM patients, 74% of ICD patients, and 69% of CRT patients. The most significant perceived benefits were the early detection of atrial arrhythmias in pacemaker patients, lead failure in ICD patients, and worsening heart failure in CRT patients. Remote monitoring was reported to lead a reduction of in-office follow-ups for all devices. The most important reported barrier to the implementation of RM for all CIEDs was lack of reimbursement (80% of centres). Physicians regard RM of CIEDs as a clinically useful technology that affords significant benefits for patients and healthcare organizations. Remote monitoring, however, is perceived as increasing workload. Reimbursement for RM is generally perceived as a major barrier to implementation. PMID:25713012

  17. Altered mechanical state in the embryonic heart results in time-dependent decreases in cardiac function.

    PubMed

    Johnson, Brennan; Bark, David; Van Herck, Ilse; Garrity, Deborah; Dasi, Lakshmi Prasad

    2015-11-01

    Proper blood flow patterns are critical for normal cardiac morphogenesis, a process that occurs rapidly in order to support further development of all tissue and organs. Previously, intracardiac fluid forces have been shown to play a critical role in cardiac morphogenesis. Altered blood flow in early development can result in an array of cardiac defects including ventricular septal defects, valve malformations, and impaired cardiac looping. However, given the dynamic and highly transient nature of cardiac morphogenesis, time dependency of the mechanical environment as an epigenetic factor in relation to intracardiac forces must be significant. Here, we show that abnormal cardiac loading adversely influences cardiac morphology only during certain time windows, thus confirming that mechanical factors are a time-dependent epigenetic factor. To illustrate this, groups of zebrafish embryos were spaced at 6-h increments from 24 to 48 h post-fertilization (hpf) in which embryos were centrifuged to generate a noninvasive alteration of cardiac preload in addition to an overall hypergravity environment. We found that earlier and later treatment groups responded with altered morphology and function, while the group with altered preload from 30 to 36 hpf had no effect. These results demonstrate the inherently time-dependent nature of epigenetic factors as pertaining to intracardiac forces and external mechanical factors. Further, it underscores the highly coupled nature of programmed biology and mechanical forces during cardiac morphogenesis. Future studies with respect to surgical correction during cardiac morphogenesis must consider timing to optimize therapeutic impact. PMID:25976479

  18. A pacemaker powered by an implantable biofuel cell operating under conditions mimicking the human blood circulatory system--battery not included.

    PubMed

    Southcott, Mark; MacVittie, Kevin; Halámek, Jan; Halámková, Lenka; Jemison, William D; Lobel, Robert; Katz, Evgeny

    2013-05-01

    Biocatalytic electrodes made of buckypaper were modified with PQQ-dependent glucose dehydrogenase on the anode and with laccase on the cathode and were assembled in a flow biofuel cell filled with serum solution mimicking the human blood circulatory system. The biofuel cell generated an open circuitry voltage, Voc, of ca. 470 mV and a short circuitry current, Isc, of ca. 5 mA (a current density of 0.83 mA cm(-2)). The power generated by the implantable biofuel cell was used to activate a pacemaker connected to the cell via a charge pump and a DC-DC converter interface circuit to adjust the voltage produced by the biofuel cell to the value required by the pacemaker. The voltage-current dependencies were analyzed for the biofuel cell connected to an Ohmic load and to the electronic loads composed of the interface circuit, or the power converter, and the pacemaker to study their operation. The correct pacemaker operation was confirmed using a medical device - an implantable loop recorder. Sustainable operation of the pacemaker was achieved with the system closely mimicking human physiological conditions using a single biofuel cell. This first demonstration of the pacemaker activated by the physiologically produced electrical energy shows promise for future electronic implantable medical devices powered by electricity harvested from the human body. PMID:23519144

  19. Health Instruction Packages: Cardiac Anatomy.

    ERIC Educational Resources Information Center

    Phillips, Gwen; And Others

    Text, illustrations, and exercises are utilized in these five learning modules to instruct nurses, students, and other health care professionals in cardiac anatomy and functions and in fundamental electrocardiographic techniques. The first module, "Cardiac Anatomy and Physiology: A Review" by Gwen Phillips, teaches the learner to draw and label…

  20. GPCR signaling and cardiac function.

    PubMed

    Capote, Leany A; Mendez Perez, Roberto; Lymperopoulos, Anastasios

    2015-09-15

    G protein-coupled receptors (GPCRs), such as ?-adrenergic and angiotensin II receptors, located in the membranes of all three major cardiac cell types, i.e. myocytes, fibroblasts and endothelial cells, play crucial roles in regulating cardiac function and morphology. Their importance in cardiac physiology and disease is reflected by the fact that, collectively, they represent the direct targets of over a third of the currently approved cardiovascular drugs used in clinical practice. Over the past few decades, advances in elucidation of their structure, function and the signaling pathways they elicit, specifically in the heart, have led to identification of an increasing number of new molecular targets for heart disease therapy. Here, we review these signaling modalities employed by GPCRs known to be expressed in the cardiac myocyte membranes and to directly modulate cardiac contractility. We also highlight drugs and drug classes that directly target these GPCRs to modulate cardiac function, as well as molecules involved in cardiac GPCR signaling that have the potential of becoming novel drug targets for modulation of cardiac function in the future. PMID:25981298

  1. Redox Control of Cardiac Excitability

    PubMed Central

    Aggarwal, Nitin T.

    2013-01-01

    Abstract Reactive oxygen species (ROS) have been associated with various human diseases, and considerable attention has been paid to investigate their physiological effects. Various ROS are synthesized in the mitochondria and accumulate in the cytoplasm if the cellular antioxidant defense mechanism fails. The critical balance of this ROS synthesis and antioxidant defense systems is termed the redox system of the cell. Various cardiovascular diseases have also been affected by redox to different degrees. ROS have been indicated as both detrimental and protective, via different cellular pathways, for cardiac myocyte functions, electrophysiology, and pharmacology. Mostly, the ROS functions depend on the type and amount of ROS synthesized. While the literature clearly indicates ROS effects on cardiac contractility, their effects on cardiac excitability are relatively under appreciated. Cardiac excitability depends on the functions of various cardiac sarcolemal or mitochondrial ion channels carrying various depolarizing or repolarizing currents that also maintain cellular ionic homeostasis. ROS alter the functions of these ion channels to various degrees to determine excitability by affecting the cellular resting potential and the morphology of the cardiac action potential. Thus, redox balance regulates cardiac excitability, and under pathological regulation, may alter action potential propagation to cause arrhythmia. Understanding how redox affects cellular excitability may lead to potential prophylaxis or treatment for various arrhythmias. This review will focus on the studies of redox and cardiac excitation. Antioxid. Redox Signal. 18, 432–468. PMID:22897788

  2. Cardiac Rehabilitation in Real Life

    PubMed Central

    Jankowski, Piotr; Pajak, Andrzej; Lysek, Radoslaw; Lukaszewska, Anna; Wolfshaut-Wolak, Renata; Bogacki, Piotr; Grodecki, Janusz; Mirek-Bryniarska, Ewa; Nessler, Jadwiga; Podolec, Piotr; Kawecka-Jaszcz, Kalina; Czarnecka, Danuta

    2015-01-01

    Abstract Participation in cardiac rehabilitation programs (CRPs) improves prognosis in patients with coronary artery disease (CAD). However, not much is known about the effectiveness of CRP in real life. The aim of this analysis was to identify factors related to the referral to CRP following hospitalization for CAD and estimate the effectiveness of the programs in real life. Medical records of 1061 consecutive patients aged ?80 years, hospitalized due to an acute coronary syndrome or for a myocardial revascularization procedure in 5 hospitals serving the city and surrounding counties, were reviewed and 611 patients were interviewed 6–18 months posthospitalization. Of 611 patients participating in the interview, 212 (34.7%) were referred following the hospitalization to a center providing CRP. Age, hospitalization in a teaching hospital, and index diagnosis were independently related to being granted a referral. Among the referred patients, 86.3% participated in the CRP. Participation in CRP was related to the lower probability of having high total cholesterol (23% vs 32%, P?programs should vary depending on the education level of the participants. PMID:26266357

  3. Cardiac Rehabilitation in Real Life.

    PubMed

    Jankowski, Piotr; Pajak, Andrzej; Lysek, Radoslaw; Lukaszewska, Anna; Wolfshaut-Wolak, Renata; Bogacki, Piotr; Grodecki, Janusz; Mirek-Bryniarska, Ewa; Nessler, Jadwiga; Podolec, Piotr; Kawecka-Jaszcz, Kalina; Czarnecka, Danuta

    2015-08-01

    Participation in cardiac rehabilitation programs (CRPs) improves prognosis in patients with coronary artery disease (CAD). However, not much is known about the effectiveness of CRP in real life. The aim of this analysis was to identify factors related to the referral to CRP following hospitalization for CAD and estimate the effectiveness of the programs in real life.Medical records of 1061 consecutive patients aged ?80 years, hospitalized due to an acute coronary syndrome or for a myocardial revascularization procedure in 5 hospitals serving the city and surrounding counties, were reviewed and 611 patients were interviewed 6-18 months posthospitalization.Of 611 patients participating in the interview, 212 (34.7%) were referred following the hospitalization to a center providing CRP. Age, hospitalization in a teaching hospital, and index diagnosis were independently related to being granted a referral. Among the referred patients, 86.3% participated in the CRP. Participation in CRP was related to the lower probability of having high total cholesterol (23% vs 32%, P?programs should vary depending on the education level of the participants. PMID:26266357

  4. [No compression of cardiac cavities in transthoracic ultrasound does not exclude cardiac tamponade.

    PubMed

    Juhl-Olsen, Peter; Frederiksen, Christina Alcaraz; Sloth, Erik

    2014-11-24

    The clinical presentation of cardiac tamponade is difficult to distinguish from other causes of shock. Pericardial fluid is easy to visualize with cardiac ultrasound and a key sign of overt cardiac tamponade is the compression of right side cavities. We present two cases in which cardiac tamponade was present, but where compression of cardiac cavities could not be demon-strated with transthoracic cardiac ultrasound. This emphasizes that cardiac tamponade is still a clinical diagnosis. PMID:25430575

  5. Oleandrin: A cardiac glycosides with potent cytotoxicity

    PubMed Central

    Kumar, Arvind; De, Tanmoy; Mishra, Amrita; Mishra, Arun K.

    2013-01-01

    Cardiac glycosides are used in the treatment of congestive heart failure and arrhythmia. Current trend shows use of some cardiac glycosides in the treatment of proliferative diseases, which includes cancer. Nerium oleander L. is an important Chinese folk medicine having well proven cardio protective and cytotoxic effect. Oleandrin (a toxic cardiac glycoside of N. oleander L.) inhibits the activity of nuclear factor kappa-light-chain-enhancer of activated B chain (NF-?B) in various cultured cell lines (U937, CaOV3, human epithelial cells and T cells) as well as it induces programmed cell death in PC3 cell line culture. The mechanism of action includes improved cellular export of fibroblast growth factor-2, induction of apoptosis through Fas gene expression in tumor cells, formation of superoxide radicals that cause tumor cell injury through mitochondrial disruption, inhibition of interleukin-8 that mediates tumorigenesis and induction of tumor cell autophagy. The present review focuses the applicability of oleandrin in cancer treatment and concerned future perspective in the area. PMID:24347921

  6. Leadership in cardiac surgery.

    PubMed

    Rao, Christopher; Patel, Vanash; Ibrahim, Michael; Ahmed, Kamran; Wong, Kathie A; Darzi, Ara; von Segesser, Ludwig K; Athanasiou, Thanos

    2011-06-01

    Despite the efficacy of cardiac surgery, less invasive interventions with more uncertain long-term outcomes are increasingly challenging surgery as first-line treatment for several congenital, degenerative and ischemic cardiac diseases. The specialty must evolve if it is to ensure its future relevance. More importantly, it must evolve to ensure that future patients have access to treatments with proven long-term effectiveness. This cannot be achieved without dynamic leadership; however, our contention is that this is not enough. The demands of a modern surgical career and the importance of the task at hand are such that the serendipitous emergence of traditional charismatic leadership cannot be relied upon to deliver necessary change. We advocate systematic analysis and strategic leadership at a local, national and international level in four key areas: Clinical Care, Research, Education and Training, and Stakeholder Engagement. While we anticipate that exceptional individuals will continue to shape the future of our specialty, the creation of robust structures to deliver collective leadership in these key areas is of paramount importance. PMID:20884217

  7. Cardiac Remodeling in Obesity

    PubMed Central

    ABEL, E. DALE; LITWIN, SHELDON E.; SWEENEY, GARY

    2010-01-01

    The dramatic increase in the prevalence of obesity and its strong association with cardiovascular disease have resulted in unprecedented interest in understanding the effects of obesity on the cardiovascular system. A consistent, but puzzling clinical observation is that obesity confers an increased susceptibility to the development of cardiac disease, while at the same time affording protection against subsequent mortality (termed the obesity paradox). In this review we focus on evidence available from human and animal model studies and summarize the ways in which obesity can influence structure and function of the heart. We also review current hypotheses regarding mechanisms linking obesity and various aspects of cardiac remodeling. There is currently great interest in the role of adipokines, factors secreted from adipose tissue, and their role in the numerous cardiovascular complications of obesity. Here we focus on the role of leptin and the emerging promise of adiponectin as a cardioprotective agent. The challenge of understanding the association between obesity and heart failure is complicated by the multifaceted interplay between various hemodynamic, metabolic, and other physiological factors that ultimately impact the myocardium. Furthermore, the end result of obesity-associated changes in the myocardial structure and function may vary at distinct stages in the progression of remodeling, may depend on the individual pathophysiology of heart failure, and may even remain undetected for decades before clinical manifestation. Here we summarize our current knowledge of this complex yet intriguing topic. PMID:18391168

  8. Decoding the Cardiac Message

    PubMed Central

    Dorn, Gerald W

    2012-01-01

    This review reflects and expands upon the contents of the author’s presentation at The Thomas W. Smith Memorial Lecture at AHA Scientific Sessions, 2011. “Decoding the cardiac message” refers to accumulating results from ongoing microRNA research that is altering longstanding concepts of the mechanisms for, and consequences of, messenger RNA (mRNA) regulation in the heart. First, I provide a brief historical perspective of the field of molecular genetics, touching upon seminal research that paved the way for modern molecular cardiovascular research and helped establish the foundation for current concepts of mRNA regulation in the heart. I follow with some interesting details about the specific research that led to the discovery and appreciation of microRNAs as highly conserved pivotal regulators of RNA expression and translation. Finally, I provide a personal viewpoint as to how agnostic genome-wide techniques for measuring microRNAs, their mRNA targets, and their protein products can be applied in an integrated multi-systems approach to uncover direct and indirect effects of microRNAs. Experimental designs integrating next-generation sequencing and global proteomics have the potential to address unanswered questions regarding microRNA-mRNA interactions in cardiac disease, how disease alters mRNA targeting by specific microRNAs, and how mutational and polymorphic nucleotide variation in microRNAs can affect end-organ function and stress-response. PMID:22383710

  9. Refinement of a limit cycle oscillator model of the effects of light on the human circadian pacemaker

    NASA Technical Reports Server (NTRS)

    Jewett, M. E.; Kronauer, R. E.; Brown, E. N. (Principal Investigator)

    1998-01-01

    In 1990, Kronauer proposed a mathematical model of the effects of light on the human circadian pacemaker. Although this model predicted many general features of the response of the human circadian pacemaker to light exposure, additional data now available enable us to refine the original model. We first refined the original model by incorporating the results of a dose response curve to light into the model's predicted relationship between light intensity and the strength of the drive onto the pacemaker. Data from three bright light phase resetting experiments were then used to refine the amplitude recovery characteristics of the model. Finally, the model was tested and further refined using data from an extensive phase resetting experiment in which a 3-cycle bright light stimulus was presented against a background of dim light. In order to describe the results of the four resetting experiments, the following major refinements to the original model were necessary: (i) the relationship between light intensity (I) and drive onto the pacemaker was reduced from I1/3 to I0.23 for light levels between 150 and 10,000 lux; (ii) the van der Pol oscillator from the original model was replaced with a higher-order limit cycle oscillator so that amplitude recovery is slower near the singularity and faster near the limit cycle; (iii) a direct effect of light on circadian period (tau x) was incorporated into the model such that as I increases, tau x decreases, which is in accordance with "Aschoff's rule". This refined model generates the following testable predictions: it should be difficult to enhance normal circadian amplitude via bright light; near the critical point of a type 0 phase response curve (PRC) the slope should be steeper than it is in a type 1 PRC; and circadian period measured during forced desynchrony should be directly affected by ambient light intensity.

  10. Mesothelial/monocytic incidental cardiac excrescence mimicking cardiac tumor.

    PubMed

    Mallick, Saumyaranjan; Arava, Sudheer; Muthukumaran, Subramanian; Sharma, Bhavna; Choudhary, Shiv Kumar; Ray, Ruma

    2016-01-01

    Mesothelial incidental cardiac excrescence is a non-neoplastic tumor-like lesion commonly occurring in the intracardiac region. The exact etiology is unclear. A 32-year-old woman presented with respiratory distress on exertion. Echocardiography showed severe aortic, mitral, and tricuspid regurgitation, for which triple-valve replacement was performed. A small cardiac excrescence was found over the aortic valve, measuring 0.6?×?0.3?×?0.3-cm, which on microscopy showed features of mesothelial/monocytic incidental cardiac excrescence. This condition is very rare but it must be recognized because it mimics a metastatic malignancy. PMID:24838237

  11. Best Practices for Counseling in Cardiac Rehabilitation Settings

    ERIC Educational Resources Information Center

    Sheikh, Alia I.; Marotta, Sylvia A.

    2008-01-01

    Heart disease is the leading cause of death in the United States and can affect individuals of all ages, gender, ethnicity, and socioeconomic status. This article reviews the research on psychosocial interventions in cardiac rehabilitation programs and discusses the evolving set of best practices for counselors working in a new setting with people…

  12. ECG Monitoring in Cardiac Rehabilitation: Is It Needed?

    ERIC Educational Resources Information Center

    Greenland, Philip; Pomilla, Paul V.

    1989-01-01

    Discusses the controversial use of continuous electrocardiogram (ECG) monitoring as a safety measure in cardiac rehabilitation exercise programs. Little evidence substantiates its value for all patients during exercise. In the absence of empirical evidence documenting the worth of this expensive procedure, it is recommended for use with high-risk…

  13. Synchronization of sinoatrial node pacemaker cell clocks and its autonomic modulation impart complexity to heart beating intervals Short title: Beating-rate variability of sinoatrial node cells

    PubMed Central

    Yaniv, Yael; Ahmet, Ismayil; Liu, Jie; Lyashkov, Alexey E.; Guiriba, Toni-Rose; Okamoto, Yosuke; Ziman, Bruce D.; Lakatta, Edward G.

    2014-01-01

    Background A reduction of complexity of heart-beat interval variability (BIV) that is associated with an increased morbidity and mortality in cardiovascular disease states is thought to derive from the balance of sympathetic and parasympathetic neural impulses to the heart. But rhythmic clock-like behavior intrinsic to pacemaker cells within the sinoatrial node (SAN) drives their beating, even in the absence of autonomic neural input. Objective To test how this rhythmic clock-like behavior intrinsic to pacemaker cells interacts with autonomic impulses to the heart-beat interval variability in vivo. Methods We analyzed BIV in the time and frequency domains and by fractal and entropy analyses: i) in vivo, when the brain input to the SAN is intact; ii) during autonomic denervation in vivo; iii) in isolated SAN tissue (i.e., in which the autonomic-neural input is completely absent); iv) in single pacemaker cells isolated from the SAN; and v) following autonomic receptor stimulation of these cells. Results Spontaneous-beating intervals of pacemaker cells residing within the isolated SAN tissue exhibit fractal-like behavior and have lower approximate entropy than in the intact heart. Isolation of pacemaker cells from SAN tissue, however, leads to a loss in the beating-interval order and fractal-like behavior. ? adrenergic receptor stimulation of isolated pacemaker cells increases intrinsic clock synchronization, decreases their action potential period and increases system complexity. Conclusions Both the average-beating interval in vivo and beating interval complexity are conferred by the combined effects of clock periodicity intrinsic to pacemaker cells and their response to autonomic-neural input. PMID:24713624

  14. Cardiac cone-beam CT

    SciTech Connect

    Manzke, Robert . E-mail: robert.manzke@philips.com

    2005-10-15

    This doctoral thesis addresses imaging of the heart with retrospectively gated helical cone-beam computed tomography (CT). A thorough review of the CT reconstruction literature is presented in combination with a historic overview of cardiac CT imaging and a brief introduction to other cardiac imaging modalities. The thesis includes a comprehensive chapter about the theory of CT reconstruction, familiarizing the reader with the problem of cone-beam reconstruction. The anatomic and dynamic properties of the heart are outlined and techniques to derive the gating information are reviewed. With the extended cardiac reconstruction (ECR) framework, a new approach is presented for the heart-rate-adaptive gated helical cardiac cone-beam CT reconstruction. Reconstruction assessment criteria such as the temporal resolution, the homogeneity in terms of the cardiac phase, and the smoothness at cycle-to-cycle transitions are developed. Several reconstruction optimization approaches are described: An approach for the heart-rate-adaptive optimization of the temporal resolution is presented. Streak artifacts at cycle-to-cycle transitions can be minimized by using an improved cardiac weighting scheme. The optimal quiescent cardiac phase for the reconstruction can be determined automatically with the motion map technique. Results for all optimization procedures applied to ECR are presented and discussed based on patient and phantom data. The ECR algorithm is analyzed for larger detector arrays of future cone-beam systems throughout an extensive simulation study based on a four-dimensional cardiac CT phantom. The results of the scientific work are summarized and an outlook proposing future directions is given. The presented thesis is available for public download at www.cardiac-ct.net.

  15. SU-E-T-557: Measuring Neutron Activation of Cardiac Devices Irradiated During Proton Therapy Using Indium Foils

    SciTech Connect

    Avery, S; Christodouleas, J; Delaney, K; Diffenderfer, E; Brown, K

    2014-06-01

    Purpose: Measuring Neutron Activation of Cardiac devices Irradiated during Proton Therapy using Indium Foils Methods: The foils had dimensions of 25mm x 25mm x 1mm. After being activated, the foils were placed in a Canberra Industries well chamber utilizing a NaI(Tl) scintillation detector. The resulting gamma spectrum was acquired and analyzed using Genie 2000 spectroscopy software. One activation foil was placed over the upper, left chest of RANDO where a pacemaker would be. The rest of the foils were placed over the midline of the patient at different distances, providing a spatial distribution over the phantom. Using lasers and BBs to align the patient, 200 MU square fields were delivered to various treatment sites: the brain, the pancreas, and the prostate. Each field was shot at least a day apart, giving more than enough time for activity of the foil to decay (t1=2 = 54.12 min). Results: The net counts (minus background) of the three aforementioned peaks were used for our measurements. These counts were adjusted to account for detector efficiency, relative photon yields from decay, and the natural abundance of 115-In. The average neutron flux for the closed multi-leaf collimator irradiation was measured to be 1.62 x 106 - 0.18 x 106 cm2 s-1. An order of magnitude estimate of the flux for neutrons up to 1 keV from Diffenderfer et al. gives 3 x 106 cm2 s-1 which does agree on the order of magnitude. Conclusion: Lower energy neutrons have higher interaction cross-sections and are more likely to damage pacemakers. The thermal/slow neutron component may be enough to estimate the overall risk. The true test of the applicability of activation foils is whether or not measurements are capable of predicting cardiac device malfunction. For that, additional studies are needed to provide clinical evidence one way or the other.

  16. Physics of Cardiac Arrhythmogenesis

    NASA Astrophysics Data System (ADS)

    Karma, Alain

    2013-04-01

    A normal heartbeat is orchestrated by the stable propagation of an excitation wave that produces an orderly contraction. In contrast, wave turbulence in the ventricles, clinically known as ventricular fibrillation (VF), stops the heart from pumping and is lethal without prompt defibrillation. I review experimental, computational, and theoretical studies that have shed light on complex dynamical phenomena linked to the initiation, maintenance, and control of wave turbulence. I first discuss advances made to understand the precursor state to a reentrant arrhythmia where the refractory period of cardiac tissue becomes spatiotemporally disordered; this is known as an arrhythmogenic tissue substrate. I describe observed patterns of transmembrane voltage and intracellular calcium signaling that can contribute to this substrate, and symmetry breaking instabilities to explain their formation. I then survey mechanisms of wave turbulence and discuss novel methods that exploit electrical pacing stimuli to control precursor patterns and low-energy pulsed electric fields to control turbulence.

  17. Cardiac action potential imaging

    NASA Astrophysics Data System (ADS)

    Tian, Qinghai; Lipp, Peter; Kaestner, Lars

    2013-06-01

    Action potentials in cardiac myocytes have durations in the order of magnitude of 100 milliseconds. In biomedical investigations the documentation of the occurrence of action potentials is often not sufficient, but a recording of the shape of an action potential allows a functional estimation of several molecular players. Therefore a temporal resolution of around 500 images per second is compulsory. In the past such measurements have been performed with photometric approaches limiting the measurement to one cell at a time. In contrast, imaging allows reading out several cells at a time with additional spatial information. Recent developments in camera technologies allow the acquisition with the required speed and sensitivity. We performed action potential imaging on isolated adult cardiomyocytes of guinea pigs utilizing the fluorescent membrane potential sensor di-8-ANEPPS and latest electron-multiplication CCD as well as scientific CMOS cameras of several manufacturers. Furthermore, we characterized the signal to noise ratio of action potential signals of varying sets of cameras, dye concentrations and objective lenses. We ensured that di-8-ANEPPS itself did not alter action potentials by avoiding concentrations above 5 ?M. Based on these results we can conclude that imaging is a reliable method to read out action potentials. Compared to conventional current-clamp experiments, this optical approach allows a much higher throughput and due to its contact free concept leaving the cell to a much higher degree undisturbed. Action potential imaging based on isolated adult cardiomyocytes can be utilized in pharmacological cardiac safety screens bearing numerous advantages over approaches based on heterologous expression of hERG channels in cell lines.

  18. Videoscope-assisted cardiac surgery

    PubMed Central

    Chen, Robert Jeen-Chen

    2014-01-01

    Videoscope-assisted cardiac surgery (VACS) offers a minimally invasive platform for most cardiac operations such as coronary and valve procedures. It includes robotic and thoracoscopic approaches and each has strengths and weaknesses. The success depends on appropriate hardware setup, staff training, and troubleshooting efficiency. In our institution, we often use VACS for robotic left-internal-mammary-artery takedown, mitral valve repair, and various intra-cardiac operations such as tricuspid valve repair, combined Maze procedure, atrial septal defect repair, ventricular septal defect repair, etc. Hands-on reminders and updated references are provided for reader’s further understanding of the topic. PMID:24455172

  19. Videoscope-assisted cardiac surgery.

    PubMed

    Chiu, Kuan-Ming; Chen, Robert Jeen-Chen

    2014-01-01

    Videoscope-assisted cardiac surgery (VACS) offers a minimally invasive platform for most cardiac operations such as coronary and valve procedures. It includes robotic and thoracoscopic approaches and each has strengths and weaknesses. The success depends on appropriate hardware setup, staff training, and troubleshooting efficiency. In our institution, we often use VACS for robotic left-internal-mammary-artery takedown, mitral valve repair, and various intra-cardiac operations such as tricuspid valve repair, combined Maze procedure, atrial septal defect repair, ventricular septal defect repair, etc. Hands-on reminders and updated references are provided for reader's further understanding of the topic. PMID:24455172

  20. Epigenetic regulation in cardiac fibrosis

    PubMed Central

    Yu, Li-Ming; Xu, Yong

    2015-01-01

    Cardiac fibrosis represents an adoptive response in the heart exposed to various stress cues. While resolution of the fibrogenic response heralds normalization of heart function, persistent fibrogenesis is usually associated with progressive loss of heart function and eventually heart failure. Cardiac fibrosis is regulated by a myriad of factors that converge on the transcription of genes encoding extracellular matrix proteins, a process the epigenetic machinery plays a pivotal role. In this mini-review, we summarize recent advances regarding the epigenetic regulation of cardiac fibrosis focusing on the role of histone and DNA modifications and non-coding RNAs. PMID:26635926