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1

Cardiac pacemaker power sources  

Microsoft Academic Search

A review of chemical and radioisotope batteries used in cardiac ; pacemakers is presented. The battery systems are examined in terms of longevity, ; reliability, cost, size and shape, energy density, weight, internal resistance ; versus time, end-of-life voltage, chemical compatibility, and potential failure ; mechanisms. (TFD)

K. A. Gasper; K. E. Fester

1975-01-01

2

Trends in Cardiac Pacemaker Batteries  

PubMed Central

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.

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

2004-01-01

3

Reuse of permanent cardiac pacemakers.  

PubMed Central

Cardiac pacemakers are part of a growing group of expensive implantable electronic devices; hospitals in which 100 pacemakers are implanted per year must budget over $300 000 for these devices. This cost represents a considerable burden to health care resources. Since the "life-span" of modern pacemakers often exceeds that of the patients who receive them, the recovery and reuse of these devices seems logical. Pacemakers can be resterilized and tested with current hospital procedures. Reuse should be acceptable under Canadian law, but the manner in which the pacemakers are recovered and the patients selected should follow careful guidelines. Every patient should provide written informed consent before receiving a recovered pacemaker. Properly executed, reuse of pacemakers should provide a high level of health care while maintaining or reducing the cost of these devices.

Rosengarten, M D; Portnoy, D; Chiu, R C; Paterson, A K

1985-01-01

4

Development of a Pacemaker Monitor with Cardiac Simulator.  

National Technical Information Service (NTIS)

A cardiac pacemaker monitoring system was developed for use in testing cardiac pacemakers in RF fields. The system provided for both continuous monitoring of the pacemaker output and simulating normal cardiac activity at the pacemaker leads. Fiber optics ...

T. O. Steiner

1975-01-01

5

Dual-chamber cardiac pacemaker tester.  

PubMed

To investigate the operation of dual-chamber cardiac pacemakers, a pacemaker tester is developed that is able to examine pacemaker parameters, demand modes and rate-adaptive modes. The tester generates simplified electrograms and responds to pacemaker pulses in a closed-loop simulation. The authors describe the hardware and the software algorithm of the tester. To demonstrate the capabilities of the tester, four tests are presented, together with their results on a rate-adaptive dual-chamber pacemaker. PMID:9684467

Galuschky, C W; Webster, J G

1998-03-01

6

Space Derived Health Aids (Cardiac Pacemaker)  

NASA Technical Reports Server (NTRS)

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.

1981-01-01

7

Continued Evaluation of Cardiac Pacemakers.  

National Technical Information Service (NTIS)

The nuclear powered pacemaker evaluation was designed to characterize the operating characteristics of such pacemakers and identify potential failure mechanisms. More than 30 nuclear powered pacemakers were implanted in dogs and 15 were subjected to high ...

E. E. Brueschke E. F. Uretz R. G. Hauser

1976-01-01

8

The functional testing of external cardiac pacemakers  

Microsoft Academic Search

In common with all other biomedical equipment, cardiac pacemakers should be routinely tested and serviced. Experience has shown that although they are generally very reliable some faults have occurred that might have been detected by regular testing. A testing protocol is suggested that has two levels, routine tests that check the essential functions of the pacemakers and supplementary tests that

M. P. Watts; A. L. Evans

1988-01-01

9

Epithermal neutron beam interference with cardiac pacemakers.  

PubMed

In this paper, a phantom study was performed to evaluate the effect of an epithermal neutron beam irradiation on the cardiac pacemaker function. Severe malfunction occurred in the pacemakers after substantially lower dose from epithermal neutron irradiation than reported in the fast neutron or photon beams at the same dose rate level. In addition the pacemakers got activated, resulting in nuclides with half-lives from 25 min to 115 d. We suggest that BNCT should be administrated only after removal of the pacemaker from the vicinity of the tumor. PMID:21478029

Koivunoro, H; Serén, T; Hyvönen, H; Kotiluoto, P; Iivonen, P; Auterinen, I; Seppälä, T; Kankaanranta, L; Pakarinen, S; Tenhunen, M; Savolainen, S

2011-12-01

10

Early Mesodermal Cues Assign Avian Cardiac Pacemaker Fate-Potential in a Tertiary Heart Field**  

PubMed Central

Cardiac pacemaker cells autonomously generate electrical impulses that initiate and maintain the rhythmic contraction of the heart. Although the majority of the heart is thought to originate from the primary and secondary heart fields, we report that chick pacemaker cells arise from a discrete region of mesoderm outside of these fields. Shortly after gastrulation, canonical Wnts promote the recruitment of mesodermal cells within this region into the pacemaker lineage. These findings identify the ontogeny of cardiac pacemaker cells, suggesting that pacemaker cells are physically segregated and molecularly programmed in a tertiary heart field, prior to the onset of cardiac morphogenesis.

Bressan, Michael; Liu, Gary; Mikawa, Takashi

2013-01-01

11

EMF interference detection utilizing the recording feature of cardiac pacemakers  

Microsoft Academic Search

Electromagnetic (EMF) interference with cardiac pacemakers may occur in various work environments. In the case of interfering external signals, the pacemaker may misinterpret the signal as a heart-related problem and initiate treatment procedures unnecessarily. We evaluated the applicability of the interference recording feature of cardiac pacemakers to identify the interfering sources. The pacemakers were exposed to a wide variety of

Tommi Alanko; Maria Tiikkaja; Harri Lindholm; Maila Hietanen

2011-01-01

12

Technical Series Trends in Cardiac Pacemaker Batteries  

Microsoft Academic Search

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,

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

13

Pacemaker interactions induce reentrant wave dynamics in engineered cardiac culture  

NASA Astrophysics Data System (ADS)

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.

Borek, Bart?omiej; Shajahan, T. K.; Gabriels, James; Hodge, Alex; Glass, Leon; Shrier, Alvin

2012-09-01

14

Ischemic stroke after cardiac pacemaker implantation in sick sinus syndrome  

Microsoft Academic Search

The risk of embolic stroke during sick sinus syndrome before cardiac pacemaker insertion is substantial, but stroke after pacemaker insertion has not been well studied. We observed 10 sick sinus syndrome patients who developed an ischemic stroke 4 days to 112 months after pacemaker insertion. Nine patients represented 6% of the 156 ischemic stroke patients observed during a 30-month period.

Marc Fisher; Carlos S. Kase; Barbara Stelle; Mills Roger M. Jr

1988-01-01

15

A Portable Miniature Transistorized Radio-Frequency Coupled Cardiac Pacemaker  

Microsoft Academic Search

A miniature, transistorized radio-frequency-coupled cardiac pacemaker was developed to eliminate wires penetrating the skin when electrodes are placed on the heart to drive it. The design also eliminates the need for totally implanting a pacemaker with its batteries. The stimulating impulse is transmitted via amplitude modulation to a tuned circuit and detector assembly implanted below the skin. The output of

D. M. Hickman; L. A. Geddes; H. E. Hoff; M. Hinds; A. G. Moore; C. K. Francis; T. Engen

1961-01-01

16

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

PubMed Central

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

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

2013-01-01

17

Sexual dimorphism in the complexity of cardiac pacemaker activity  

NSDL National Science Digital Library

Journal article titled "Sexual Dimorphism in the Complexity of Cardiac Pacemaker Activity" from The American Journal of PhysiologyÃÂHeart and Circulatory Physiology, by Terry B. J. Kuo, and Cheryl C. H. Yang.

Terry B. Kuo (Tzu Chi Buddhist General Hospital Department of Neurology); Cheryl C.H. Yang (Tzu Chi University Department of Physiology)

2007-10-03

18

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

PubMed

A variation in pacemaker stimulus amplitude can represent pacemaker system dysfunction from generator malfunction, lead insulation defect, lead fracture, or artefact of digital signal processing of the electrocardiography recorder. Pacemaker lead perforation into the pericardial space typically results in loss of capture which was not demonstrated in our patient. In summary, we report an unusual ECG finding of pacemaker stimulus amplitude alteration without loss of capture in the setting of cardiac tamponade from pacemaker lead perforation. PMID:23830112

Suksaranjit, P; Prasidthrathsint, K

2014-01-01

19

[Use of a temporal cardiac pacemaker in patients undergoing a major non-cardiac surgery].  

PubMed

This is a report of the use of transvenous temporal pacemaker in 18 patients, with an average age of 59.3 years, that under want non cardiac major surgery. They did not have cardiac simptoms but had conduction abnormalities in the preoperative electrocardiogram. A pacemaker was implanted as a prophylaxis against arrythmia during the transoperative and postoperative periods. There was no incidence of transoperative arrythmia. Three patients died in the immediate postoperative period, two due to duffuse carcinomatosis and one due to diabetic acidosis. The average duration of the implanted pacemaker was 12.7 days, and three patients required a permanent pacemaker. Case five is exemplificative of the benefits of the temporal pacemaker, he had a preoperative electrocardiogram showing trifascicular block, he was taken to the operating room and anesthesia was induced, the patient had a cardiac arrest but recovered without secuela; latter on a temporal pacemaker was inserted and the patient had surgery without cardiac problems. PMID:757608

Robles González, L; Vázquez Cabrales, A; Chiw Castillo, G; Sánchez Ibarra, J H; Pérez Redondo, H

1978-01-01

20

Effect of Electric and Magnetic Fields Near an HVDC Converter Terminal on Implanted Cardiac Pacemakers. Final Report.  

National Technical Information Service (NTIS)

The electromagnetic fields associated with HVDC converters and transmission lines constitute a unique environment for persons with implanted cardiac pacemakers. A measurement program has been conducted to assess the potential interfering effects of these ...

M. J. Frazier

1980-01-01

21

Long-term evaluation of the General Electric cardiac pacemaker  

Microsoft Academic Search

A review of General Electric (G.E.) electronic cardiac pacemakers for symptomatic complete A-V heart block in two sequential three-year periods at the University of Michigan Medical Center indicates that there has been no increase in the useful life of these units. With G.E. epicardial pacemakers failure occurred after an average of 12 months. In the early years the major cause

Donald R. Kahn; Marvin M. Kirsh; Sathaporn Vathayanon; Park W. Willis; Joseph A. Walton; Karen McIntosh; Pauline W. Ferguson; Herbert Sloan

1970-01-01

22

Magnetic interference of cardiac pacemakers from a surgical magnetic drape.  

PubMed

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

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

2013-03-01

23

ISOTOPE BATTERY FOR CARDIAC PACEMAKER ISOCARD  

Microsoft Academic Search

The description concerns a miniaturized, thermoelectric converter system which is intended for use in conjunction with a Pu 238 heat source as the power supply for pacemakers. It consists of a continuous meadering line of thermocouples vapour-deposited onto a polyimide tape. The system supplies directly the necessary output voltage of 6 V. The most important stages in the production process,

Renner

1971-01-01

24

Semiconductor Measurement Technology: Reliability Technology for Cardiac Pacemakers III - A Workshop Report.  

National Technical Information Service (NTIS)

The workshop, third in a series, served as a forum for pacemaker manufacturers and other interested parties to address technical questions relevant to the enhancement and assurance of cardiac pacemaker reliability. Extended summaries are provided of 27 ta...

H. A. Schafft

1979-01-01

25

The pacemaker current in cardiac Purkinje myocytes  

PubMed Central

It is generally assumed that in cardiac Purkinje fibers the hyperpolarization activated inward current i(f) underlies the pacemaker potential. Because some findings are at odds with this interpretation, we used the whole cell patch clamp method to study the currents in the voltage range of diastolic depolarization in single canine Purkinje myocytes, a preparation where many confounding limitations can be avoided. In Tyrode solution ([K+]o = 5.4 mM), hyperpolarizing steps from Vh = -50 mV resulted in a time-dependent inwardly increasing current in the voltage range of diastolic depolarization. This time- dependent current (iKdd) appeared around -60 mV and reversed near EK. Small superimposed hyperpolarizing steps (5 mV) applied during the voltage clamp step showed that the slope conductance decreases during the development of this time-dependent current. Decreasing [K+]o from 5.4 to 2.7 mM shifted the reversal potential to a more negative value, near the corresponding EK. Increasing [K+]o to 10.8 mM almost abolished iKdd. Cs+ (2 mM) markedly reduced or blocked the time-dependent current at potentials positive and negative to EK. Ba2+ (4 mM) abolished the time-dependent current in its usual range of potentials and unmasked another time-dependent current (presumably i(f)) with a threshold of approximately -90 mV (> 20 mV negative to that of the time-dependent current in Tyrode solution). During more negative steps, i(f) increased in size and did not reverse. During i(f) the slope conductance measured with small (8-10 mV) superimposed clamp steps increased. High [K+]o (10.8 mM) markedly increased and Cs+ (2 mM) blocked i(f). We conclude that: (a) in the absence of Ba2+, a time-dependent current does reverse near EK and its reversal is unrelated to K+ depletion; (b) the slope conductance of that time-dependent current decreases in the absence of K+ depletion at potentials positive to EK where inactivation of iK1 is unlikely to occur. (c) Ba2+ blocks this time-dependent current and unmasks another time-dependent current (i(f)) with a more negative (> 20 mV) threshold and no reversal at more negative values; (d) Cs+ blocks both time-dependent currents recorded in the absence and presence of Ba2+. The data suggest that in the diastolic range of potentials in Purkinje myocytes there is a voltage- and time-dependent K+ current (iKdd) that can be separated from the hyperpolarization- activated inward current i(f).

1995-01-01

26

Long-term evaluation of the General Electric cardiac pacemaker  

PubMed Central

A review of General Electric (G.E.) electronic cardiac pacemakers for symptomatic complete A-V heart block in two sequential three-year periods at the University of Michigan Medical Center indicates that there has been no increase in the useful life of these units. With G.E. epicardial pacemakers failure occurred after an average of 12 months. In the early years the major cause of failure was wire breakage, and the later major cause was battery exhaustion or component failure. Exit block was a major complication. There was no improvement when G.E. catheter pacemakers were used instead of the epicardial type. The Medtronic catheter pacemakers lasted longer, with fewer battery and component failures and no instances of exit block. Although infection was more common with Medtronic pacemakers, secondary to erosion of the power unit or the catheter through the skin, it may be that this complication could be eliminated by locating the battery box beneath the latissimus dorsi muscle in the axilla and by careful catheter placement to avoid pressure necrosis and subsequent cutaneous perforation.

Kahn, Donald R.; Kirsh, Marvin M.; Vathayanon, Sathaporn; Willis, Park W.; Walton, Joseph A.; McIntosh, Karen; Ferguson, Pauline W.; Sloan, Herbert

1970-01-01

27

A two-stator MEMS power generator for cardiac pacemakers  

Microsoft Academic Search

The design of a bio-mechanically driven double stator axial flux MEMS power generator for use in cardiac pacemakers has been presented. In the system, an asymmetrical circular rotor embedded with alternate polarity microfabricated NdFeB permanent magnets oscillates around a central shaft due to the motion of the thorax during breathing to induce a voltage across the stator coils. The generator

Jose Martinez-quijada; Sazzadur Chowdhury

2008-01-01

28

Materials aspects of implantable cardiac pacemaker leads.  

PubMed

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

Bruck, S D; Mueller, E P

1988-01-01

29

Automated and manufacturer independent assessment of the battery status of implanted cardiac pacemakers by electrocardiogram analysis  

Microsoft Academic Search

According to international standards, cardiac pacemakers have to indicate the status of their batteries upon magnet application by specific stimulation patterns. The purpose of this study has been to assess whether this concept can be used as a basis for automated and manufacturer independent examination of the depletion level of pacemakers in the framework of a collaborative telemedical pacemaker follow-up

G. Schreier; D. Hayn; A. Kollmann; D. Scherr; P. Lercher; B. Rotman; W. Klein

2004-01-01

30

PP2 Prevents ?-Adrenergic Stimulation of Cardiac Pacemaker Activity.  

PubMed

: One of the main strategies for cancer therapy is to use tyrosine kinase inhibitors for inhibiting tumor proliferation. Increasing evidence has demonstrated the potential risks of cardiac arrhythmias (such as prolonged QT interval) of these drugs. We report here that a widely used selective inhibitor of Src tyrosine kinases, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2), can inhibit and prevent ?-adrenergic stimulation of cardiac pacemaker activity. First, in dissected rat sinus node, PP2 inhibited and prevented the isoproterenol-induced increase of spontaneous beating rate. Second, in isolated rat sinus node myocytes, PP2 suppressed the hyperpolarization-activated "funny" current (traditionally called cardiac pacemaker current, If) by negatively shifting the activation curve and decelerating activation kinetics. Third, in isolated rat sinus node myocytes, PP2 decreased the Src kinase activity, the cell surface expression, and tyrosine phosphorylation of hyperpolarization-activated, cyclic nucleotide-modulated channel 4 (HCN4) channel proteins. Finally, in human embryonic kidney 293 cells overexpressing recombinant human HCN4 channels, PP2 reversed the enhancement of HCN4 channels by isoproterenol and inhibited 573x, a cyclic adenosine momophosphate-insensitive human HCN4 mutant. These results demonstrated that inhibition of Src kinase activity in heart by PP2 decreased and prevented ?-adrenergic stimulation of cardiac pacemaker activity. These effects are mediated, at least partially, by a cAMP-independent attenuation of channel activity and cell surface expression of HCN4, the main channel protein that controls the heart rate. PMID:24566462

Huang, Jianying; Lin, Yen-Chang; Hileman, Stan; Martin, Karen H; Hull, Robert; Yu, Han-Gang

2014-06-01

31

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

PubMed Central

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

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

2011-01-01

32

A Pu238O2 Nuclear Power Source for Implantable Cardiac Pacemakers  

Microsoft Academic Search

Implantable cardiac pacemakers are currently powered by mercury batteries. These cells have approximately 50-percent reliability for 2-year operation in this application. The patient has an expected lifetime of five and one-half years. Thus the cardiac pacemaker must be replaced several times during the patient's lifetime.

Wilson Greatbatch; Thomas S. Bustard

1973-01-01

33

Conceptual Design of GaN Betavoltaic Battery using in Cardiac Pacemaker  

Microsoft Academic Search

Pacemaker is an electronic biomedical device which stimulates and regulates or amplify the human heartbeat by delivering weak electrical pulses to the cardiac muscle at regular intervals when its natural regulating mechanisms break down. The purpose of the present work is to introduce a kind of low power Betavoltaic battery using in nuclear powered cardiac pacemakers which have higher efficiency

M. Mohamadian; S. A. H. Feghhi; H. Afarideh

34

Bilateral extracorporeal shock wave lithotripsy in a spinal cord injury patient with a cardiac pacemaker  

Microsoft Academic Search

Objectives: To review the precautions to be observed before and during extracorporeal shock wave lithotripsy (ESWL) in spinal cord injury (SCI) patients with a cardiac pacemaker and the safety of bilateral ESWL performed on the same day.Design: A case report of bilateral ESWL in a SCI patient with a permanent cardiac pacemaker.Setting: The Regional Spinal Injuries Centre, Southport, the Lithotripsy

S Vaidyanathan; R Hirst; KF Parsons; G Singh; BM Soni; T Oo; A Zaidi; JWH Watt; P Sett

2001-01-01

35

Computed tomography in patients with cardiac pacemakers: difficulties and solutions  

Microsoft Academic Search

The presence of cardiac pacemaker systems may significantly limit interpretation of multi-slice computed tomography (MSCT)\\u000a images. In 80 patients (45 men; aged 69.5 ± 13.4) with previously implanted anti-arrhythmic devices, a 64-slice CT (Aquilion-64)\\u000a was performed. In 61 patients (76.3%), ECG gating was used (coronaries visualization) and in 19 patients (23.7%) without ECG\\u000a gating (not coronaries visualization). In all 19 patients without

Rafal Mlynarski; Maciej Sosnowski; Agnieszka Mlynarska; Micha? Tendera

36

Phase resetting properties of cardiac pacemaker cells  

PubMed Central

Aggregates of heart cells from chicken embryos beat spontaneously. We used intracellular microelectrodes to record the periodic behavior of the membrane potential that triggers the contractions. Every 5-12 beats, a short current pulse was applied at various points in the cycle to study the phase-dependent resetting of the rhythm. Pulses stronger than 2.5 nA caused the final rhythm to be reset to almost the same point in the cycle regardless of the phase at which the pulse was applied (type zero resetting). Pulses of less than or equal to 1 nA only caused a slight change of the phase. Increasing current intensities to between 1 and 2.5 nA gave rise to an increasing steepness in a small part of the phase-response curve. The observation of type zero resetting implies the existence of a critical stimulation that might annihilate the rhythm. Although we did find a phase at which more or less random responses occurred, the longest pause in the rhythm was 758 ms, 2.4 times the spontaneous interval. This suggests that the resting membrane potential was unstable, at least against the internal noise of the system. The conclusions are discussed in terms of the concepts of classical cardiac electrophysiology.

1984-01-01

37

Pacemaker Standard: Labeling Requirements, Performance Requirements, and Terminology for Implantable Artificial Cardiac Pacemakers.  

National Technical Information Service (NTIS)

A pacemaker standard was developed by an AAMI Pacemaker Standards Subcommittee consisting of approximately 40 physicians, clinical engineers, and consulting manufacturers. The Subcommittee was broken down into six working groups: labeling; marking and ide...

1975-01-01

38

Influence of 50 Hz electrical and magnetic fields on cardiac pacemakers.  

National Technical Information Service (NTIS)

The influence of the electromagnetic interference (EMI) on performance of 15 implanted cardiac pacemakers was tested during exposure at a high voltage substation. There were eight single and four dual chamber generator models produced by four manufacturer...

L. Toivonen R. Metso J. Valjus M. Hongisto

1991-01-01

39

Popeye domain-containing proteins and stress-mediated modulation of cardiac pacemaking.  

PubMed

An intricate network of ion channels and pumps are involved in generating a diastolic pacemaker potential, which is transmitted to the working myocardium with the help of the cardiac conduction system. The principles of cardiac pacemaking are reasonably well understood, however, the mechanism by which the heart increases its beating frequency in response to adrenergic stimulation has not been fully worked out. The Popeye domain-containing (Popdc) genes encode plasma membrane-localized proteins that are able to bind cAMP with high affinity; mice with null mutations in Popdc1 or 2 have a stress-induced pacemaker dysfunction. The phenotype in both mutants develops in an age-dependent manner and thus may model pacemaker dysfunction in man, as well as provide novel mechanistic insights into the process of pacemaker adaptation to stress. PMID:23562093

Simrick, Subreena; Schindler, Roland F; Poon, Kar-Lai; Brand, Thomas

2013-10-01

40

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

NASA Astrophysics Data System (ADS)

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

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

1985-11-01

41

Effects of 60-Heartz electric and magnetic fields on implanted cardiac pacemakers. Final report. [Hazards of power transmission line frequencies  

Microsoft Academic Search

The effects of 60-Hz electric and magnetic fields of exta-high voltage (EHV) transmission lines on the performance of implanted cardiac pacemakers were studied by: (1) in vitro bench tests of a total of thirteen cardiac pacemakers; (2) in vivo tests of six implanted cardiac pacemakers in baboons; and (3) non-hazardous skin measurement tests on four humans. Analytical methods were developed

J. E. Bridges; M. J. Frazier

1979-01-01

42

Pacemakers  

MedlinePLUS

... com ct150109 Last reviewed: 01/17/2013 7 Airport security devices do not harm pacemakers. The metal shell ... should not set off the security alarm at airport security checkpoints. However, if this should happen, show your ...

43

Programmable Pacemaker  

NASA Technical Reports Server (NTRS)

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.

1996-01-01

44

Sick Sinus Syndrome: Experience of a Cardiac Pacemaker Clinic  

Microsoft Academic Search

Out of a pacemaker clinic population of 182 patients 21 (11·5%) were found to have the sick sinus syndrome. Their ages ranged from 30 to 80 years and averaged 62. Ischaemic heart disease was more commonly an aetiological factor than in patients with chronic atrioventricular heart block. Other aetiologies were familial cardiomyopathy, postcardiac surgery, and dystrophia myotonica.Cardioversion before pacemaker insertion

Dorothy J. Radford; D. G. Julian

1974-01-01

45

Digital implementation of a wavelet-based event detector for cardiac pacemakers  

Microsoft Academic Search

This paper presents a digital hardware implementation of a novel wavelet-based event detector suitable for the next generation of cardiac pacemakers. Significant power savings are achieved by introducing a second operation mode that shuts down 2\\/3 of the hardware for long time periods when the pacemaker patient is not exposed to noise, while not degrading performance. Due to a 0.13-?m

Joachim Neves Rodrigues; Thomas Olsson; Leif Sörnmo; Viktor Öwall

2005-01-01

46

Genetic isolation of stem cell-derived pacemaker-nodal cardiac myocytes.  

PubMed

Dysfunction of the cardiac pacemaker tissues due to genetic defects, acquired diseases, or aging results in arrhythmias. When arrhythmias occur, artificial pacemaker implants are used for treatment. However, the numerous limitations of electronic implants have prompted studies of biological pacemakers that can integrate into the myocardium providing a permanent cure. Embryonic stem (ES) cells cultured as three-dimensional (3D) spheroid aggregates termed embryoid bodies possess the ability to generate all cardiac myocyte subtypes. Here, we report the use of a SHOX2 promoter and a Cx30.2 enhancer to genetically identify and isolate ES cell-derived sinoatrial node (SAN) and atrioventricular node (AVN) cells, respectively. The ES cell-derived Shox2 and Cx30.2 cardiac myocytes exhibit a spider cell morphology and high intracellular calcium loading characteristic of pacemaker-nodal myocytes. These cells express abundant levels of pacemaker genes such as endogenous HCN4, Cx45, Cx30.2, Tbx2, and Tbx3. These cells were passaged, frozen, and thawed multiple times while maintaining their pacemaker-nodal phenotype. When cultured as 3D aggregates in an attempt to create a critical mass that simulates in vivo architecture, these cell lines exhibited an increase in the expression level of key regulators of cardiovascular development, such as GATA4 and GATA6 transcription factors. In addition, the aggregate culture system resulted in an increase in the expression level of several ion channels that play a major role in the spontaneous diastolic depolarization characteristic of pacemaker cells. We have isolated pure populations of SAN and AVN cells that will be useful tools for generating biological pacemakers. PMID:23877224

Hashem, Sherin I; Claycomb, William C

2013-11-01

47

Arc welding interference recorded by an implanted cardiac pacemaker.  

PubMed

This report describes asymptomatic interference by electric arc welding with an implanted dual-chamber pacemaker. The interfering artefacts were automatically recorded and stored in the device memory. PMID:15913816

Trigano, Alexandre; Deloy, Pierre; Blandeau, Olivier; Levy, Samuel

2006-04-28

48

Implanted cardiac pacemaker pulses as recorded from the body surface.  

PubMed

This study investigates the characteristics of contemporary pacemaker pulses as recorded from the body surface. Twelve-lead paced ECGs from 140 patients (68 ± 12 years, 71% males) were collected at 32,000 samples per second. Pacer pulses were manually annotated based on the high-sampling rate data stream. The results show that durations of the various pulses are stable, while amplitudes exhibit large variations. Also, more than 50% of pulses have either durations <0.5 ms or amplitudes <2 mV, which are the AAMI/IEC thresholds for detection and marking of pacemaker pulses on an ECG report. Therefore the current standards for pacemaker pulse detection are not fit for purpose and require to be updated. Further, this study suggests that a high-sampling rate database should be used as a standard test for pacemaker annotation and detection from body surface ECGs. PMID:23034404

Luo, Shen; Johnston, Paul; Macfarlane, Peter W

2012-01-01

49

Program for the development of a thermoelectric battery operated by a ²³⁸Pu source for pacemakers  

Microsoft Academic Search

The Italian firm SORIN has undertaken a program for the development of a ; radioisotope battery, fueled with²³⁸ Pu which could be used for powering a ; cardiac pacemaker with a lifetime of about ten years. The design criteria for ; the battery, based on thermoelectric conversion, are described. The results ; obtained on the way to develop a model

B. Chinaglia; F. Vercellotti

1972-01-01

50

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

NASA Astrophysics Data System (ADS)

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

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

51

Case Report Cardiac Pacemaker Battery Discharge After External Electrical Cardioversion for Broad QRS Complex Tachycardia  

Microsoft Academic Search

External electrical cardioversion or defibrillation may be necessary in patients with implanted cardiac pacemaker (PM) or implantable cardioverter defibrillator (ICD). Sudden discharge of high electrical energy employed in direct current (DC) transthoracic countershock may damage the PM\\/ICD system resulting in a series of possible device malfunctions. For this reason, when defibrillation or cardioversion must be attempted in a patient with

Martino Annamaria; Scapigliati Andrea; Casella Michela; Sanna Tommaso; Pelargonio Gemma; Dello Russo Antonio; Zamparelli Roberto; Paulis Stefano; Bellocci Fulvio; Schiavello Rocco

52

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)

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.

Soukup, Ladislav; Vondra, Vlastimil; Viš?or, Ivo; Jurák, Pavel; Halámek, Josef

2013-04-01

53

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

PubMed Central

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

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

2014-01-01

54

Pulse measurements on mercury batteries for cardiac pacemakers  

Microsoft Academic Search

In the practical use of pacemakers there are still some problems, especially in regard to the state of the batteries. This\\u000a paper describes methods and results obtained by discharging the mercury batteries (type RM1N) with constant current pulses\\u000a of different duty cycles and amplitudes. Finally, the corresponding model in a steady-state condition is reported and the\\u000a behaviour of the components

M. Bracale; P. Contillo

1976-01-01

55

Programmable Pacemaker.  

National Technical Information Service (NTIS)

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, In...

1996-01-01

56

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

Microsoft Academic Search

The effects of Nd:YAG laser beam welding process parameters on the resulting heat input in 304L stainless steel cardiac pacemaker batteries have been studied. By careful selection of process parameters, the results can be used to reduce temperatures near glass-to-metal seals and assure hermeticity in laser beam welding of high reliability components. Three designed response surface experiments were used to

P. W. Fuerschbach; D. A. Hinkley

1997-01-01

57

Development of an electrostatic generator for a cardiac pacemaker that harnesses the ventricular wall motion  

Microsoft Academic Search

A variable-capacitance-type electrostatic (VCES) generator that harnesses ventricular motion was developed with the aim of\\u000a driving a cardiac pacemaker permanently without a battery. The developed model of the VCES generator was handmade, but it\\u000a was too large to implant into the thoracic cavity of a laboratory animal. For this reason, to demonstrate its feasibility,\\u000a a somewhat complicated method that measured

Ryoichi Tashiro; Nobuyuki Kabei; Kunimasa Katayama; E. Tsuboi; K. Tsuchiya

2002-01-01

58

Application of a vagal nerve stimulator in an epilepsy patient with cardiac pacemaker after post-ictal cardiac arrest.  

PubMed

In this case report we present a patient with temporal lobe epilepsy (TLE) showing partial complex seizures and secondary generalization, and treated with several antiepileptic drugs. After two consecutive seizures she had an episode of cardiac arrest followed by AV-block III which led to the implantation of a cardiac pacemaker. She subsequently received a vagal nerve stimulator because of poor response to epilepsy treatment. Combined treatment with two different electromagnetic stimulators raises the question of safety during surgery which is discussed. PMID:19053951

Cáceres, R; Richter, J; Säfström, K; Landtblom, A-M

2009-08-01

59

Mortality in Patients on Renal Replacement Therapy and Permanent Cardiac Pacemakers  

PubMed Central

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

Vanerio, Gabriel; Garcia, Cristina; Gonzalez, Carlota; Ferreiro, Alejandro

2014-01-01

60

[Lithium-powered cardiac pacemakers. A survey of 3 years' clinical experience (author's transl)].  

PubMed

In addition to the lithium-iodine cell which has been in clinical use since 1972, the following lithium-based power sources for cardiac pacemakers are available: The lithium-silver chromate cell (SAFT), the lithium-thionylchloride-battery (G.T.E.), the lithium-cupric sulfide cell (DuPont) and the lithium-lead iodide cell (Mallory). These batteries differ not only in their energy providing chemical reaction and their components (liquid electrolyte or not), but also in their capacity and discharge characteristics. Out of 244 lithium-powered pacemakers implanted during the past 3 years, 5 pulse generators had to be removed due to electronic circuit failure, whereas battery failure has not been observed up till now. Sensing problems were registered in 8 cases probably due to the specific properties of the entrance filter and entrance resistance of the pacer. In some cases, however, they were caused by poor electrode position. One pacemaker model, powered with the WGL702 cell, frequently gave rise to skin necrosis, Newer models have more favourable dimensions and lower specific weight. The capacity of their batteries is sufficient for middle to long-term stimulation when using current saving electrodes. Because of the well-known advantages of the lithium-cells in comparison to conventional Mallory batteries, together with the favorable clinical results, only lithium-powered pacemakers have been implanted in our hospital since 1977. PMID:927292

Präuer, H W; Wirtzfeld, A; Lampadius, M; Himmler, C; Werber, K

1977-11-01

61

Ictal asystole--late manifestation of partial epilepsy and importance of cardiac pacemaker.  

PubMed

Ictal asystole (IA) is a life-threatening complication of epilepsy and is a potential mechanism of sudden unexplained death in epilepsy (SUDEP). This entity has been proven by multiple case reports and small case series. The management of the patients with IA is still in early phase of discussion. We report a patient with medically intractable cryptogenic partial epilepsy for 27 years who presented with new onset drop attacks. During the epilepsy monitoring unit stay he was found to have a left fronto-temporal partial onset seizures which triggered brady-arrhythmia followed by asystole for 20s. A cardiac pacemaker was implanted and the patient was followed for 2 years. He continued to have simple and complex partial seizures but did not have drop attacks anymore. He still occasionally feels the activation of his pacemaker during simple partial phase of his seizures but the characteristic loss of muscle tone never happened again which made him highly satisfied. Our case demonstrates that IA can even happen decades after the onset of epilepsy. Cardiac pacemaker should be considered in all patients with IA as it prevents ictal falls and possibly SUDEP. PMID:19414273

Zubair, Salman; Arshad, Ahmed B; Saeed, Bilal; Luqman, Shoaib; Oommen, Kalarickal J

2009-07-01

62

Formal Development of a Cardiac Pacemaker: From Specification to Code  

NASA Astrophysics Data System (ADS)

This paper presents a formal development of a cardiac pacing system based on a Boston Scientific's model, a pilot case study from the Grand Challenge in Software Verification. We present a summary of our Z model of the system, its translation into Perfect Developer, and the code generation and execution. Further practical result and analysis are also in the context of this paper.

Gomes, Artur O.; Oliveira, Marcel V. M.

63

Prevention of hemodynamic instability in extra-cranial carotid angioplasty and stenting using temporary transvenous cardiac pacemaker.  

PubMed

Hemodynamic instability is a common condition during extra-cranial carotid angioplasty and stenting (CAS). We evaluated the safety and efficacy of prophylactic placement of temporary cardiac pacemaker during extra-cranial CAS for the prevention of hemodynamic instability. For this, forty-seven carotid artery stents were deployed in 41 high-risk patients. Temporary transvenous cardiac pacemakers were inserted before CAS procedure. The pacers were set to capture a heart rate <60 bpm. Clinical symptoms, blood pressure, heart rate, and pacing activation were monitored and data were collected. We found that pacing occurred in 25 carotid lesions during balloon predilatation; pacemakers were activated transiently in 25 patients. The longest pacing continued for 1 day. Among cases with pacemaker activation, 1 patient developed post-procedural symptomatic hypotension that lasted for 4 days. No related complications were observed. It was, therefore, concluded that pacing was technically effective in producing electrical ventricular responses and was hemodynamically effective in 25 carotid lesions which underwent balloon predilatation. The prophylactic use of a temporary transvenous cardiac pacemaker during CAS was rapid and effective in controlling peri-operative hemodynamic instability and preventing stroke and other complications. The prophylactic use of temporary pacemaker is particularly recommended for patients at high risk for developing hemodynamic instability. PMID:23090784

Liu, Juan; Yao, Guo-en; Zhou, Hua-dong; Jiang, Xiao-jiang; Chen, Qiao

2013-03-01

64

[GSTCVS certificate for cardiac pacemaker, ICD and CRT therapy].  

PubMed

Medical qualifications to perform operations with cardiac electronic implantable devices as well as for preoperative and postoperative therapy, including follow-up in this patient population are not well defined. Based on recommendations which have been worked out and published by an interdisciplinary consensus of cardiac surgeons, cardiologists and electrophysiologists, a certificate with three modules has been developed by the Working Group for Electrophysiologic Surgery of the German Society for Thoracic and Cardiovascular Surgery (GSTCVS, Deutsche Gesellschaft für Thorax-, Herz- und Gefäßchirurgie, DGTHG). First examinations for this certificate will be held in 2013 and transitional regulations apply until 1st April 2014. Further details are available on the homepage of the GSTCVS. PMID:23754588

Markewitz, A; Burger, H; Osswald, B; Israel, C W; Doll, N; Hemmer, W; Beckmann, A

2013-06-01

65

Cardiac Pacemaker Activity: From Single Cells to Modelling the Heart  

Microsoft Academic Search

\\u000a Since the introduction of the methods of cell isolation, patch clamping, cell dialysis and intracellular ion indicators, very\\u000a major advances have been made in understanding the electrophysiology of cardiac cells (for recent reviews see Noble, 1984; Noble & Powell, 1987; Irisawa, Brown & Giles, 1992). As the information has been made sufficiently precise, it has been incorporated into mathematical models,

D. Noble; J. C. Denyer; H. F. Brown; R. Winslow; A. Kimball

66

Programmable Pacemaker  

NASA Technical Reports Server (NTRS)

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

1980-01-01

67

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

PubMed

Tests were conducted on rechargeable mercury-zinc pacemaker batteries under simulated and actual biologic conditions, using a variety of discharge rates and charging schedules. In tests on 96 cells at a 6.4 milliampere (ma) discharge, recharging once every 15 months of simulated pacing at a 25 microampere (mua) drain, the earliest cell failure occurred after an equivalent of 50 years of pacing. The mean pacing equivalent for all 96 cells was more than 140 years. In 6.4 ma discharge tests on 24 cells, recharging once every 8 days of simulated pacing, only 1 cell in 24 failed after an equivalent of more than 500 years of pacing (actual time 2 years). In tests on 13 cells pacing at a 200 mua drain without recharging, the simulated mean duration of pacing before total discharge was 4.8 years. Seven other cells at a 200 mua drain with periodic recharging continue to function normally after more than 7 years of actual time, simulating 56 years of pacing at a 25 mua drain. Cardiac pacemakers using the rechargeable mercury-zinc cell have been implanted in animals for more than 2 1/2 years and in patients for more than 1 year with all units continuing to function satisfactorily. It has been demonstrated unequivocally that a rechargeable mercury-zinc pacemaker will function continuously for more than 4 years without recharging and that periodic recharging will extend pacing life far beyond that predicted for lithium and nuclear primary power sources. PMID:983958

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

1976-11-01

68

Immediate and 12 months follow up of function and lead integrity after cranial MRI in 356 patients with conventional cardiac pacemakers  

PubMed Central

Background Conventional cardiac pacemakers are still often regarded as a contraindication to magnetic resonance imaging (MRI). We conducted this study to support the hypothesis that it is safe to scan patients with cardiac pacemakers in a 1.5 Tesla MRI, if close supervision and monitoring as well as adequate pre- and postscan programming is provided. Methods We followed up 356 patients (age 61.3?±?9.1 yrs., 229 men) with single (n?=?132) or dual chamber (n?=?224) cardiac pacemakers and urgent indication for a cranial MRI for 12 months. The scans were performed at 1.5T. During the scan patients were monitored with a 3-lead ECG and pulse oximetry. Prior to the scan pacemakers were programmed according to our own protocol. Results All 356 scans were completed without complications. No arrhythmias were induced, programmed parameters remained unchanged. No pacemaker dysfunction was identified. Follow-up examinations were performed immediately, 2 weeks, 2, 6, and 12 months after the scan. There was no significant change of pacing capture threshold (ventricular 0.9?±?0.4 V@0.4 ms, atrial 0.9?±?0.3 V@0.4 ms) immediately (ventricular 1.0?±?0.3 V@0.4 ms, atrial 0.9?±?0.4 V@0.4 ms) or at 12 months follow-up examinations (ventricular 0.9?±?0.2 V@0.4 ms, atrial 0.9?±?0.3 V@0.4 ms). There was no significant change in sensing threshold (8.0?±?4.0 mV vs. 8.1?±?4.2 mV ventricular lead, 2.0?±?0.9 mV vs. 2.1?±?1.0 mV atrial lead) or lead impedance (ventricular 584?±?179?? vs. 578?±?188??, atrial 534?±?176?? vs. 532?±?169??) after 12 months. Conclusions This supports the evidence that patients with conventional pacemakers can safely undergo cranial MRI in a 1.5T system with suitable preparation, supervision and precautions. Long term follow-up did not reveal significant changes in pacing capture nor sensing threshold.

2014-01-01

69

Mechanisms of beat-to-beat regulation of cardiac pacemaker cell function by Ca²? cycling dynamics.  

PubMed

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

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

2013-10-01

70

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

NASA Astrophysics Data System (ADS)

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.

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

2008-01-01

71

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

NASA Astrophysics Data System (ADS)

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

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

2009-06-01

72

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

PubMed

Peripheral sympathetic overdrive in young obese subjects contributes to further aggravation of insulin resistance, diabetes, and hypertension, thus inducing worsening clinical conditions in adulthood. Exercise training has been considered a strategy to repair obesity autonomic dysfunction, thereby reducing the cardiometabolic risk. Therefore, the aim of this study was to assess the effect of early exercise training, starting immediately after weaning, on cardiac autonomic control in diet-induced obese rats. Male Wistar rats (weaning) were divided into four groups: (i) a control group (n = 6); (ii) an exercise-trained control group (n = 6); (iii) a diet-induced obesity group (n = 6); and (iv) an exercise-trained diet-induced obesity group (n = 6). The development of obesity was induced by 9 weeks of palatable diet intake, and the training program was implemented in a motor-driven treadmill (5 times per week) during the same period. After this period, animals were submitted to vein and artery catheter implantation to assess cardiac autonomic balance by methylatropine (3 mg/kg) and propranolol (4 mg/kg) administration. Exercise training increased running performance in both groups (p < 0.05). Exercise training also prevented the increased resting heart rate in obese rats, which seemed to be related to cardiac pacemaker activity preservation (p < 0.05). Additionally, the training program preserved the pressure and bradycardia responses to autonomic blockade in obese rats (p < 0.05). An exercise program beginning at weaning age prevents cardiovascular dysfunction in obese rats, indicating that exercise training may be used as a nonpharmacological therapeutic strategy for the treatment of cardiometabolic diseases. PMID:24806307

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

2014-08-01

73

Design of wavelet-based ECG detector for implantable cardiac pacemakers.  

PubMed

A wavelet Electrocardiogram (ECG) detector for low-power implantable cardiac pacemakers is presented in this paper. The proposed wavelet-based ECG detector consists of a wavelet decomposer with wavelet filter banks, a QRS complex detector of hypothesis testing with wavelet-demodulated ECG signals, and a noise detector with zero-crossing points. In order to achieve high detection accuracy with low power consumption, a multi-scaled product algorithm and soft-threshold algorithm are efficiently exploited in our ECG detector implementation. Our algorithmic and architectural level approaches have been implemented and fabricated in a standard 0.35 ?m CMOS technology. The testchip including a low-power analog-to-digital converter (ADC) shows a low detection error-rate of 0.196% and low power consumption of 19.02 ?W with a 3 V supply voltage. PMID:23893202

Min, Young-Jae; Kim, Hoon-Ki; Kang, Yu-Ri; Kim, Gil-Su; Park, Jongsun; Kim, Soo-Won

2013-08-01

74

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

PubMed

Recurrent, pulseless-electrical-activity (PEA) cardiac arrests were the novel presentation of untreated systemic mastocytosis in an 85-year-old woman who lacked cutaneous findings of mastocytosis. Despite prior implantation of a dual-chamber cardiac pacemaker 3 weeks previously for similar spells, she experienced a PEA arrest accompanied by flushing, increased urinary N-methylhistamine excretion and serum tryptase values on the day of presentation to our clinic. Bone marrow biopsy findings conducted to rule out breast cancer metastases showed 30% mast cell infiltration, aberrant expression of CD25 and a positive c-kit Asp816Val mutation. Treatment with a combination of H1 and H2 receptor blockers reduced flushing and eliminated hypotension. Maintenance medication included aspirin, cetirizine, ranitidine, montelukast, oral cromolyn sodium and an epinephrine autoinjector (as needed). At 6-month follow-up, the patient remained free of PEA arrests, flushing, or any clinical signs of mastocytosis or mast cell degranulation. PEA cardiac arrests may therefore be a presenting sign of untreated systemic mastocytosis. PMID:24335343

Butterfield, Joseph H; Weiler, Catherine R

2014-01-01

75

Global Bifurcation Structure and Variability of Pacemaker Rhythm in a Detailed Model of Cardiac Sinoatrial Node Cells  

NASA Astrophysics Data System (ADS)

As a cardiac pacemaker, sinoatrial node spontaneously generates periodic electrical signals (action potentials) in its cells. The action potential generation is deeply related to various ion channels in cell membranes, and the abnormalities of ion channels cause sinus arrhythmia. We use the Zhang model of sinoatrial node cells to investigate the relation between pacemaker rhythm (frequency of action potential generation) and ion channels. The Zhang model is described by the Hodgkin-Huxley-type nonlinear ordinary differential equations, and its parameter values vary between periphery and center cells of sinoatrial node. We analyze the bifurcation structure of the Zhang model, and investigate the variability of pacemaker rhythm and its sensitivity on ion channel conductance changes for both periphery and center cells. Moreover, these results are compared with the previous results of another sinoatrial node cell model: Yanagihara-Noma-Irisawa model.

Pan, Zhenxing; Doi, Shinji

76

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

PubMed

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

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

77

Effects of Epinephrine on the Pacemaker Potassium Current of Cardiac Purkinje Fibers  

PubMed Central

Epinephrine promotes spontaneous activity in cardiac Purkinje fibers through its action on the pacemaker potassium current (iKK2). The mechanism of the acceleratory effect was studied by means of a voltage clamp technique. The results showed that the hormone speeds the deactivation of iKK2 during pacemaker activity by displacing the kinetic parameters of iKK2 toward less negative potentials. This depolarizing voltage shift is the sole explanation of the acceleratory effect since epinephrine did not alter the rectifier properties of iKK2, or the underlying inward leakage current, or the threshold for iNNa. The dose dependence of the voltage shift in the iKK2 activation curve was similar in 1.8 and 5.4 mM [Ca]o. The maximal voltage shift (usually ?20 mV) was produced by epinephrine concentrations of > 10-6 M. The half-maximal effect was evoked by 60 nM epinephrine, nearly an order of magnitude lower than required for half-maximal effect on the secondary inward current (Carmeliet and Vereecke, 1969). The ?-blocker propranolol (10-6 M) prevented the effect of epinephrine (10-7M) but by itself gave no voltage shift. Epinephrine shifted the activation rate coefficient ?8 to a greater extent than the deactivation rate coefficient ?8, and often steepened the voltage dependence of the steady-state activation curve. These deviations from simple voltage shift behavior were discussed in terms of possible mechanisms of epinephrine's action on the iKK2 channel.

Tsien, Richard W.

1974-01-01

78

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

PubMed

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

Quinn, T Alexander; Kohl, Peter

2012-01-01

79

Effects of an increased air gap on the in vitro interaction of wireless phones with cardiac pacemakers.  

PubMed

Several clinical and laboratory studies have demonstrated electromagnetic interaction between implantable cardiac pacemakers and hand-held wireless phones operated in close proximity. Current FDA and HIMA labeling guidelines indicate that a minimum separation of 6 in (15 cm) should be maintained between a hand-held wireless phone and an implanted pacemaker. This separation requirement does not distinguish between lateral locations on the chest and a perpendicular air gap. Evidence is provided here for a substantially reduced separation threshold when measured across an air gap rather than near the saline conductive media of a simulated torso. Twenty pacemaker-phone combinations involving 6 pacemakers and 9 phones were evaluated in vitro under worst-case conditions with respect to phone output power and pacemaker sensitivity. The phones represented CDMA, TDMA-11 Hz, TDMA-22 Hz, TDMA-50 Hz, and TDMA-217 Hz digital wireless technologies. Small increases in the perpendicular air gap between the phone and the saline surface resulted in a dramatic reduction in interaction. Approximately half of the 208 test runs exhibiting interaction at an air gap of 1 cm no longer resulted in interaction when the gap was increased to 2 cm. At a gap of 7.4 cm, the percentage of runs with interaction decreased to 1.4%. The overall interaction rate, considering a total of 8296 test runs from an earlier study, was less than 0.07% at a total perpendicular distance of 8.6 cm from the saline surface to the phone antenna axis. The perpendicular distance threshold of 8.6 cm was significantly less than the horizontal plane projection threshold of 19 cm previously reported. This difference is a function of the electromagnetic field coupling to the saline bath rather than field strength changes along the axis of the phone antenna. The results have implications for those making recommendations to pacemaker patients who may be unaware of this distinction. PMID:11015112

Grant, F H; Schlegel, R E

2000-10-01

80

[Cardiac pacemaker dysfunction due to rotation of the battery (reel syndrome)].  

PubMed

Reel syndrome is characterized by the rotation of permanent pacemaker generator on its transverse axis and electrode catheters curl around it, so this causes displacement of the electrodes with the loss of atrial and ventricular pacing. It can cause severe symptoms due to dysfunction of the pacemaker. We present three patient cases who after the placement of pacemaker attended by dysfunction of the displacement of the electrodes their clinical pictures were compatible with Reel syndrome. PMID:22882992

Guevara-Valdivia, Milton E; Leal-Ortiz, Grisel Erín; Bonilla-Morales, Iván

2012-01-01

81

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

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage...Other Health Services § 410.49 Cardiac rehabilitation program and intensive cardiac...

2010-10-01

82

[Cardiac resynchronizing therapy. Selection of patients and their management after implantation of biventricular heart pacemaker].  

PubMed

Chronic heart failure (CHF) - a widely spread manifestation of various forms of heart diseases - is characterized by high mortality. Prognosis is especially unfavorable in patients with wide QRS complex. Method of resynchronizing therapy was elaborated for the treatment of this group of patients in addition of medical therapy. Its efficacy for improvement of clinical course and prognosis of CHF was demonstrated in a number of randomized controlled trials. However according to some data in 30-45% of cases application of the method is associated with no clinical improvement or reversal of cardiac remodeling when standard criteria (left ventricular ejection fraction less or equal 35%, QRS 120-150 ms, functional class II-IV) are used for patients selection. In this review we consider possibilities of various methods of selection of patients providing maximal probability of efficacy. We also present analysis of techniques of detection of implantation site of left ventricular lead and various tactics of management of patients after implantation of biventricular pacemaker. PMID:23548431

Mareev, Iu V; Shitov, V N; Saidova, M A

2013-01-01

83

The first seven years of implantation of permanent cardiac pacemakers in a small urban community in central Croatia.  

PubMed

The aim of the study was to assess the situation with implantation of cardiac pacemakers and to critically evaluate the possibility of this method of treatment. The study was conducted from 2001 to 2007. Data on a total of 211 operations were included in the study. There were 121 (57.3%) male patients, mean age 69.7 years, and 90 (42.7%) female patients, mean age 74.5 years. Total number of operations increased from 18 in 2001 to 24 in 2002, 28 in 2003, 38 in 2004, 38 in 2005, 30 in 2006 and 35 in 2007. Primo implantation was carried out in 196 (92.9%) cases. The following types of pacemakers were used: VVI in 79 (40.3%), VVIR in 73 (37.2%), DDD in 7 (3.6%), DDDR in 18 (9.2%), VDD in 17 (8.7%) and AAIR in 2 (1.0%) cases. ECG indication was second degree heart block in 40, third degree heart block in 86, chronic atrial fibrillation with bradyarrhythmia in 57, sick sinus syndrome in 27 cases and trifascicular block in one case. The symptoms included dizziness in 126, syncope in 52, dyspnea in 45, bradycardia in 12, chest pain in 3 and cerebral dysfunction in 2 cases. In conclusion, our patients now receive appropriate treatment within a shorter time, thus reducing pressure upon large cardiac surgery centers. However, efforts should be continuously invested in approaching European standards of artificial pacemaker implantation. PMID:19388470

Horvat, Davor

2008-12-01

84

Measurement of Leaked High-Frequency Burst Electric Field and EMI Evaluation for Cardiac Pacemaker in Fusion Facility  

NASA Astrophysics Data System (ADS)

In this study, we measured the time variation of burst electric fields leaked from a heating device in the ion cyclotron range of high-frequency in an experimental fusion facility, and analyzed their statistical characteristics such as the amplitude probability distribution (APD) and crossing rate distribution (CRD). As a result, we found that the variation of the leaked electric field level is very irregular, far from the normal distribution. Moreover, the leaked electric field variation with time may reach 400 times in one second to cross its mode value. Although so, the maximum electric field intensity itself is much smaller than the ICNIRP safety guideline. In addition, we also evaluated the possibility of electromagnetic interference to an implanted cardiac pacemaker in the measured electromagnetic environment. We found that even in the worst case the interference voltage induced in the output of the pacemaker sensing circuit does still not exceed the threshold for a malfunction.

Yamanaka, Yukio; Wang, Jianqing; Fujiwara, Osamu; Uda, Tatsuhiko

85

[Prerequisites for pacemaker electrodes for individual programming of a low stimulation impulse (comparison of an Elgiloy and a steroid-dependent pacemaker electrode)].  

PubMed

The individual programming of cardiac pacemakers to pulse amplitudes of 2.5 volts and less reduces unnecessary energy consumption by the pacing impulse. In order not to impair the safety margin, electrodes must reveal a low chronic pacing threshold associated with a small standard deviation. For 3 months after implantation we investigated these conditions in 10 patients with a steroid-eluting lead and in 10 patients with a conventional elgiloy lead. During the study period patients with a steroid-eluting lead had a significantly lower pacing threshold. Twelve weeks after implantation all steroid-patients had 0.8 volts pacing threshold at 0.5 ms pulse width. In contrast to the conventional lead the steroid-eluting lead had a significantly lower impedance. Since voltage enters squared into the energy consumption formula, patients with a steroid-eluting lead needed significantly less energy for an effective stimulation of the myocardium 4 and 12 weeks after implantation. R-wave amplitude was not different in both groups. Our investigation demonstrates that immediately after implantation all patients with a steroid-eluting lead can be programmed at 2.5 volts pulse voltage or individually even lower. The saved energy results either in an extended pulse generator longevity or allows the implantation of a smaller pulse generator with a reduced battery capacity. PMID:2378158

Schuchert, A; Kuck, K H; Bleifeld, W

1990-06-01

86

Stimulateurs cardiaques et défibrillateurs automatiques implantés : connaissances basiques pour le réanimateur Cardiac pacemakers and implantable cardioverter defibrillators: basic knowledge for the ICU physician  

Microsoft Academic Search

Indications for pacemakers and implantable cardioverter defibrillators get more and more frequent with results of clinical trials. Basic knowl- edge about these devices is therefore needed by ICU physicians in order to optimise patients' treatments. Several cases of malfunctioning may occur with pacemakers and defibrillators such as empty batteries, faulty programming, increase of stimulation or defibrillation thresholds. It is necessary

C. Mathien; S. Pynn; T. Le Maitre; M. Chauvin; F. Schneider

87

The effects of electronic article surveillance systems on permanent cardiac pacemakers: an in vitro study.  

PubMed

Five Siemens Pacesetter cardiac pacemakers (PM) were subjected to in vitro testing with six different electronic article surveillance (EAS) devices. The PMs consisted of polarity programmable, dedicated bipolar, and dedicated unipolar types. EAS equipment included UHF, RF, Magnetic, and Magnetoacoustic (MA) devices from two manufacturers. Prior to testing, each PM was interrogated and normal operation confirmed. Each PM was attached to a heart simulator via an eight foot cable and then subjected to testing within the EAS field. The PMs were passed through the field in two axes, positioned stationary within the field, and, worst case (WC), placed directly against the transmitter. During testing the ECG was observed and PM behavior recorded. In one PM (Synchrony III), Event Records, and Event Histograms were utilized. At the conclusion of testing with each EAS device the PM was evaluated for normal operation. Results: No PM was reprogrammed by the EAS devices. UHF produced no effect on the PMs. RF produced noise response in one unipolar PM while in the WC position. High frequency and multifrequency magnetic units produced positive results only in the WC position. Unipolar PMs were affected more often than bipolar. MA and older magnetic EAS units produced more positive responses than newer lower power devices. One incident of close coupled (400 msec) ventricular pacing was seen with the MA EAS unit. Conclusions: UHF, RF, high frequency, and dual frequency magnetic EAS produced few effects during in vitro testing. Except with the MA and low frequency magnetic devices, positive results occurred only in WC conditions.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7845811

Lucas, E H; Johnson, D; McElroy, B P

1994-11-01

88

Cardiac pacemaker function of HCN4 channels in mice is confined to embryonic development and requires cyclic AMP  

PubMed Central

Important targets for cAMP signalling in the heart are hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels that underlie the depolarizing ‘pacemaker' current, If. We studied the role of If in mice, in which binding of cAMP to HCN4 channels was abolished by a single amino-acid exchange (R669Q). Homozygous HCN4R669Q/R669Q mice die during embryonic development. Prior to E12, homozygous and heterozygous embryos display reduced heart rates and show no or attenuated responses to catecholaminergic stimulation. Adult heterozygous mice display normal heart rates at rest and during exercise. However, following ?-adrenergic stimulation, hearts exhibit pauses and sino-atrial node block. Our results demonstrate that in the embryo, HCN4 is a true cardiac pacemaker and elevation of HCN4 channel activity by cAMP is essential for viability. In adult mice, an important function of HCN4 channels is to prevent sinus pauses during and after stress while their role as a pacemaker of the murine heart is put into question. Most importantly, our results indicate that HCN4 channels can fulfil their physiological function only when cAMP is bound.

Harzheim, Dagmar; Pfeiffer, K Holger; Fabritz, Larissa; Kremmer, Elisabeth; Buch, Thorsten; Waisman, Ari; Kirchhof, Paulus; Kaupp, U Benjamin; Seifert, Reinhard

2008-01-01

89

Oxygen uptake kinetics during low intensity exercise: relevance for rate adaptive pacemaker programming  

Microsoft Academic Search

OBJECTIVE: To establish a normal database for oxygen uptake (VO2) kinetics during low intensity treadmill exercise (LITE) testing, to be used as a guideline for programming rate adaptive pacemakers, and to determine its relation to VO2 at anaerobic threshold and peak exercise. DESIGN: VO2 kinetics during LITE were compared with VO2 at anaerobic threshold and at peak exercise. SETTING: LITE

T. Lewalter; H. Rickli; D. MacCarter; W. Jung; R. Schimpf; P. Schwartze; R. Candinas; B. Lüderitz

1997-01-01

90

Electromagnetic and radiation environment effects on pacemakers  

Microsoft Academic Search

The increase, on one hand, of patients bearing pacemakers for cardiac deficiencies and on the other hand, of the number of cancer patients, increases the probability of several simultaneous therapy needs. Cancer radiation therapy involves specific damages to sensitive electronic devices such as pacemakers. Oncologists demand risk evaluation and rules for applying radiation therapy to cancer patients bearing pacemakers. Pacemaker

J. Mouton; R. Trochet; J. Vicrey; M. Sauvage; B. Chauvenet; A. Ostrovski; E. Leroy; R. Haug; B. Dodinot; F. Joffre

1999-01-01

91

The Solid-State Lithium Battery: A New Improved Chemical Power Source for Implantable Cardiac Pacemakers  

Microsoft Academic Search

A new solid-state battery, designed for implantable prosthetics is described. Single cell voltage is 2.8 V. The anode is metallic lithium. The cathode is a proprietary iodide. The electrolyte is a crystal, lithium iodide. Cell impedance at 37°C for a typical pacemaker battery is under 1000¿ at beginning of life (BOL) and 16 000 ¿ at end of life (EOL).

Wilson Greatbatch; John H. Lee; Walter Mathias; Margery Eldridge; James R. Moser; Alan A. Schneider

1971-01-01

92

Extraction of cardiac rhythm devices: indications, techniques and outcomes for the removal of pacemaker and defibrillator leads.  

PubMed

Cardiac rhythm management devices (pacemakers) are being increasingly implanted worldwide not only for symptomatic bradycardia, but also for the management of arrhythmia and heart failure. Their use in more elderly patients with significant comorbidities is rising steeply and consequently long-term complications are increasingly arising. Such an increase in device therapy is being paralleled by an increase in the requirement for system extraction. Safe lead extraction is central to the management of much of the complications related to pacemakers. The most common indication for lead extraction is system infection Adhesions in chronically implanted leads can become major obstacles to safe lead extraction and life-threatening bleeding and cardiac perforations may occur. Over the last 20 years, specific tools and techniques for transvenous lead extraction have been developed to assist in freeing the lead body from the adhesions. This article provides a comprehensive review of the indications, tools, techniques and outcomes for transvenous lead extraction. The success rate largely depends on the time from implant. Up to 12 months from implant, it is rare that traction alone will not suffice. For longer lead implant duration, no single technique is sufficient to address all extractions, but laser provides the best chance of extracting the entire lead. Operator experience is vital in determining success as familiarity of a wide array of techniques will increase the likelihood of uncomplicated extraction. Long implantation time, lack of operator experience, ICD lead type and female gender are risk factors for life-threatening complications. Lead extraction should therefore, ideally be performed in high volume centres with experienced staff and on-site support from a cardiothoracic surgical team able to deal with bleeding complications from cardiovascular perforation. PMID:20642712

Farooqi, F M; Talsania, S; Hamid, S; Rinaldi, C A

2010-07-01

93

Mechanisms of Intrinsic Beating Variability in Cardiac Cell Cultures and Model Pacemaker Networks  

PubMed Central

Heart rate variability (HRV) exhibits fluctuations characterized by a power law behavior of its power spectrum. The interpretation of this nonlinear HRV behavior, resulting from interactions between extracardiac regulatory mechanisms, could be clinically useful. However, the involvement of intrinsic variations of pacemaker rate in HRV has scarcely been investigated. We examined beating variability in spontaneously active incubating cultures of neonatal rat ventricular myocytes using microelectrode arrays. In networks of mathematical model pacemaker cells, we evaluated the variability induced by the stochastic gating of transmembrane currents and of calcium release channels and by the dynamic turnover of ion channels. In the cultures, spontaneous activity originated from a mobile focus. Both the beat-to-beat movement of the focus and beat rate variability exhibited a power law behavior. In the model networks, stochastic fluctuations in transmembrane currents and stochastic gating of calcium release channels did not reproduce the spatiotemporal patterns observed in vitro. In contrast, long-term correlations produced by the turnover of ion channels induced variability patterns with a power law behavior similar to those observed experimentally. Therefore, phenomena leading to long-term correlated variations in pacemaker cellular function may, in conjunction with extracardiac regulatory mechanisms, contribute to the nonlinear characteristics of HRV.

Ponard, Julien G. C.; Kondratyev, Aleksandar A.; Kucera, Jan P.

2007-01-01

94

Microcomputer and microprocessor applications in cardiac pacing.  

PubMed

Modern adaptive dual-chamber cardiac pacemakers offer millions of combinations of noninvasively programmable operating parameters. Some pacemakers and most pacemaker programmers are microprocessor based; these "software-organized" pacemakers can undergo substantial functional redesign by noninvasive programming even after implantation. Ancillary instrumentation used in making measurements during implant and follow-up is often microcomputer based, as is experimental instrumentation used in pacing research. As electrical control of cardiac dysrhythmias becomes more sophisticated, microcomputer applications in many aspects of pacing are proliferating in research, manufacturing, and clinical practice. PMID:6646017

Bernstein, A D; Parsonnet, V

1983-01-01

95

Small bowel capsule endoscopy in patients with cardiac pacemakers and implantable cardioverter defibrillators: Outcome analysis using telemetry review  

PubMed Central

AIM: To determine if there were any interactions between cardiac devices and small bowel capsules secondary to electromagnetic interference (EMI) in patients who have undergone small bowel capsule endoscopy (SBCE). METHODS: Authors conducted a chart review of 20 patients with a cardiac pacemaker (CP) or implantable cardioverter defibrillator (ICD) who underwent continuous electrocardiographic monitoring during their SBCE from 2003-2008. authors searched for unexplained electrocardiogram (ECG) findings, changes in CP and ICD set parameters, any abnormality in transmitted capsule data, and adverse clinical events. RESULTS: There were no adverse events or hemodynamically significant arrhythmias reported. CP and ICD set parameters were preserved. The majority of ECG abnormalities were also found in pre- or post- SBCE ECG tracings and the CP behavior during arrhythmias appeared appropriate. Two patients seemed to have episodes of undersensing by the CP. However, similar findings were documented in ECGs taken outside the time frame of the SBCE. One patient was observed to have a low signal encountered from the capsule resulting in lack of localization, but no images were lost. CONCLUSION: Capsule-induced EMI remains a possibility but is unlikely to be clinically important. CP-induced interference of SBCE is also possible, but is infrequent and does not result in loss of images transmitted by the capsule.

Cuschieri, Justin R; Osman, Mohammed N; Wong, Richard CK; Chak, Amitabh; Isenberg, Gerard A

2012-01-01

96

Pacemakers—A journey through the years  

Microsoft Academic Search

This is an article on the history of artificial cardiac pacemakers. Before the advent of pacemakers, not much could be done\\u000a for patients who suffered from cardiac asystole and other cardiac rhythm disturbances. Although the concept that an artificial\\u000a pacemaker could be used to stimulate the heart in standstill evolved much earlier, it was not until 1952 that the first

Tarun Mittal

2005-01-01

97

Impact of imaging landmark on the risk of MRI-related heating near implanted medical devices like cardiac pacemaker leads.  

PubMed

Implanted medical devices such as cardiac pacemakers pose a potential hazard in magnetic resonance imaging. Electromagnetic fields have been shown to cause severe radio frequency-induced tissue heating in some cases. Imaging exclusion zones have been proposed as an instrument to reduce patient risk. The purpose of this study was to further assess the impact of the imaging landmark on the risk for unintended implant heating by measuring the radio frequency-induced electric fields in a body phantom under several imaging conditions at 1.5T. The results show that global radio frequency-induced coupling is highest with the torso centered along the superior-inferior direction of the transmit coil. The induced E-fields inside the body shift when changing body positioning, reducing both global and local radio frequency coupling if body and/or conductive implant are moved out from the transmit coil center along the z-direction. Adequate selection of magnetic resonance imaging landmark can significantly reduce potential hazards in patients with implanted medical devices. PMID:20806352

Nordbeck, Peter; Ritter, Oliver; Weiss, Ingo; Warmuth, Marcus; Gensler, Daniel; Burkard, Natalie; Herold, Volker; Jakob, Peter M; Ertl, Georg; Ladd, Mark E; Quick, Harald H; Bauer, Wolfgang R

2011-01-01

98

Clinical impact of surface electrocardiography of cardiac arrhythmias in pacemaker-ICD patients.  

PubMed

Cardiologists often are called to explain electrocardiograms of pacemaker/ implantable cardioverter (PMK/ICD) patients during arrhythmic events. The most frequent arrhythmia is atrial fibrillation (AF) whether in PMK or in ICD patients. Generally, it is not difficult to diagnose, it can affect the quality of life of this subgroup because it can generate inappropriate and painful therapies. Arrhythmias as atrioventricular block or other bradyarrhythmias can show a particular way of presentation specially for the device's intervention using specific algorithms that cardiologists should know to adequately interpret the phenomenon. For example, Rate Drop Response algorithm (to prevent syncope) or other antiarrhythmic functions for atrial tachyarrhythmias (Post Mode Switching Overdrive Pacing (PMOP) or Atrial Rate Stabilization) can alter surface electrocardiogram after AF or atrial ectopic beats. Ventricular arrhythmias in ICD patients are frequent. Burst, ramp and shock are therapies with a high percentage of efficacy. However, sometimes, supraventricular arrhythmias (SVT) can induce inappropriate interventions. In other cases appropriate burst, ramp or shock (during a ventricular tachycardia (VT)) can degenerate it in a fast ventricular tachycardia or in ventricular fibrillation with consequent shocks. Wavelet, onset, stability, and other algorithms, specifically in dual chamber ICDs, are used to discriminate SVT from VT assuring more specific interventions. PMID:17584683

Santini, Massimo; Aquilani, Stefano; Ricci, Renato Pietro

2007-07-01

99

An In Vivo Study of Cardiac Pacemaker Optimization by Pulse Shape Modification  

Microsoft Academic Search

This paper is an experimental extension of theoretical work previously published by one of the authors. Results of pacing a canine heart using four different increasing exponential and ramp-like waveforms are presented. It is shown that these waveforms reduce the cardiac threshold energy by as much as 14 percent when compared with a pure rectangular pulse shape and by about

Richard D. Klafter; Leonid Hrebien

1976-01-01

100

Pacemaker current inhibition in experimental human cardiac sympathetic activation: a double-blind, randomized, crossover study.  

PubMed

Hyperpolarization-activated, cyclic nucleotide-gated 4 (HCN4) channels comprise the final pathway for autonomic heart rate (HR) regulation. We hypothesized that HCN4 inhibition could reverse autonomic imbalance in a human model of cardiac sympathetic activation. Nineteen healthy men ingested oral metoprolol+reboxetine, ivabradine+reboxetine, or placebo+reboxetine in a double-blind, randomized, crossover fashion. We assessed HR, blood pressure (BP), stroke volume, and cardiac output during rest and profound orthostatic stress. HR variability, BP variability, and baroreflex sensitivity were analyzed. Metoprolol, but not ivabradine, decreased resting HR and BP. Ivabradine attenuated the HR increase to orthostatic stress, albeit to a lesser extent than metoprolol. Stroke volume and cardiac output at a given HR were significantly lower with metoprolol. Unlike metoprolol, ivabradine did not affect HR variability, BP variability, or baroreflex sensitivity. Ivabradine attenuates sympathetic influences on HR at the sinus node level, leaving myocardial sympathetic activation unopposed. Reversal of parasympathetic dysfunction by ivabradine appears limited. PMID:24509430

Schroeder, C; Heusser, K; Zoerner, A A; Großhennig, A; Wenzel, D; May, M; Sweep, F C G J; Mehling, H; Luft, F C; Tank, J; Jordan, J

2014-06-01

101

Pacemaker (image)  

MedlinePLUS

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

102

Numerical models based on a minimal set of sarcolemmal electrogenic proteins and an intracellular Ca(2+) clock generate robust, flexible, and energy-efficient cardiac pacemaking.  

PubMed

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 Ca(2+) oscillator ("Ca(2+)clock") that generates spontaneous diastolic Ca(2+) 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 Ca(2+)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 Ca(2+) pumping (i.e. Ca(2+)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 70bpm; maximum rate of 140 to 210bpm) in response to stimulation of cholinergic and ?-adrenergic receptors. We found that only those models that include a Ca(2+)clock (including the minimal 4-parameter model "ICaL+IKr+INCX+Ca(2+)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

Maltsev, Victor A; Lakatta, Edward G

2013-06-01

103

Size and Ionic Currents of Unexcitable Cells Coupled to Cardiomyocytes Distinctly Modulate Cardiac Action Potential Shape and Pacemaking Activity in Micropatterned Cell Pairs  

PubMed Central

Background Cardiac cell therapies can yield electrical coupling of unexcitable donor cells to host cardiomyocytes with functional consequences that remain unexplored. Methods and Results We micropatterned cell pairs consisting of a neonatal rat ventricular myocyte (NRVM) coupled to an engineered HEK293 cell expressing either connexin-43 (Cx43 HEK) or Kir2.1 and connexin-43 (Kir2.1+Cx43 HEK). The NRVM-HEK contact length was fixed yielding a coupling strength of 68.9±9.7 nS, while HEK size was systematically varied. With increase in Cx43 HEK size, NRVM maximal diastolic potential (MDP) was reduced from ?71.7±0.6 mV in single NRVMs to ?35.1±1.3 mV in pairs with HEK:NRVM cell surface area ratio of 1.7±0.1, while action potential upstroke ((dVm/dt)max) and duration (APD) decreased to 1.6±0.7 % and increased to 177±32% of the single NRVM values, respectively (N=21 cell pairs). Pacemaking occurred in all NRVM-Cx43 HEK pairs with cell surface area ratios of 1.1-1.9. In contrast, NRVMs coupled with Kir2.1+Cx43 HEKs of increasing size had similar MDPs, exhibited no spontaneous activity, and showed gradual decrease in APD (N=23). Furthermore, coupling single NRVMs to a dynamic clamp model of HEK cell ionic current reproduced the cardiac MDPs and pacemaking rates recorded in cell pairs, while reproducing changes in (dVm/dt)max and APD required coupling to a HEK model that also included cell membrane capacitance. Conclusions Size and ionic currents of unexcitable cells electrically coupled to cardiomyocytes distinctly affect cardiac action potential shape and initiation with important implications for the safety of cardiac cell and gene therapies.

McSpadden, Luke C.; Nguyen, Hung; Bursac, Nenad

2012-01-01

104

Rural residents' use of cardiac rehabilitation programs.  

PubMed

The goal of this study was to identify the factors that influence the use of cardiac rehabilitation services by rural residents. The Andersen-Newman framework, which consists of three determinants of health services utilization (predisposing, enabling, and need factors), was used to direct this research. The three data collection points were at time of discharge from the hospital, two weeks post discharge, and one week following the date that the cardiac rehabilitation program would have been completed. Packets for the three data collection points were unique and contained instruments to assess various factors influencing the use of health services. The sample (N = 254) were adults living in rural areas who had experienced a cardiac event and received treatment at one of four hospitals in two western states and who provided useable data on all three questionnaires. Findings indicated that 72 (28%) of the participants attended some portion of a rehabilitation program, and only 43 (17%) completed the full 36-week program. Four predisposing factors, one enabling factor, and two need factors were significant in explaining the number of cardiac rehabilitation sessions attended. Further research is needed to validate these factors and to identify others which may influence the use of cardiac rehabilitation by rural residents. Likewise, it is essential to examine alternate ways to meet the rehabilitative needs of rural cardiac clients. PMID:9682622

Johnson, J E; Weinert, C; Richardson, J K

1998-08-01

105

Legal Aspects of Cardiac Rehabilitation Exercise Programs.  

ERIC Educational Resources Information Center

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)

Herbert, William; Herbert, David L.

1988-01-01

106

Shocks from Pacemaker Cardioverter Defibrillators Increase with Amiodarone in Patients at High Risk for Sudden Cardiac Death  

Microsoft Academic Search

The efficacy of amiodarone used in combination with a pacemaker cardioverter defibrillator (PCD) to decrease episodes of ventricular tachycardia and subsequent PCD shocks is not clear. We examined a retrospective registry of 82 patients with PCD implantation to define the efficacy of amiodarone treatment. We compared patients treated with amiodarone (for 24 consecutive months without interruption) versus no amiodarone. In

Abhijit A. Shinde; Elizabeth B. Juneman; Brian Mitchell; Mary K. Pierce; Mohamed A. Gaballa; Steven Goldman; Hoang Thai

2003-01-01

107

Clinical assessment of pacemaker power sources  

Microsoft Academic Search

The development of power sources for cardiac pacemakers has progressed from a 15-year usage of mercury-zinc batteries to widely used and accepted lithium cells. At present, there are about 6 different types of lithium cells incorporated into commercially distributed pacemakers. The authors reviewed experience over a 5-year period with 1711 mercury-zinc, 130 nuclear (P238) and 1912 lithium powered pacemakers. The

M. Bilitch; V. Parsonnet; S. Furman

1980-01-01

108

[An exceptional cause of pacemaker dysfunction].  

PubMed

Twiddler syndrome is a very rare and surprising complication of pacemaker treatment. We report the case of a woman with psychiatric disease who presented two cardiac arrests due to loss of ventricular capture. Finally, pacemaker retropectoral implantation resolves the problem. PMID:21890106

Griffet, V; Lopez, M; Guérard, S

2014-02-01

109

Ca2+-stimulated Basal Adenylyl Cyclase Activity Localization in Membrane Lipid Microdomains of Cardiac Sinoatrial Nodal Pacemaker Cells*S?  

PubMed Central

Spontaneous, rhythmic subsarcolemmal local Ca2+ releases driven by cAMP-mediated, protein kinase A (PKA)-dependent phosphorylation are crucial for normal pacemaker function of sinoatrial nodal cells (SANC). Because local Ca2+ releases occur beneath the cell surface membrane, near to where adenylyl cyclases (ACs) reside, we hypothesized that the dual Ca2+ and cAMP/PKA regulatory components of automaticity are coupled via Ca2+ activation of AC activity within membrane microdomains. Here we show by quantitative reverse transcriptase PCR that SANC express Ca2+-activated AC isoforms 1 and 8, in addition to AC type 2, 5, and 6 transcripts. Immunolabeling of cell fractions, isolated by sucrose gradient ultracentrifugation, confirmed that ACs localize to membrane lipid microdomains. AC activity within these lipid microdomains is activated by Ca2+ over the entire physiological Ca2+ range. In intact SANC, the high basal AC activity produces a high level of cAMP that is further elevated by phosphodiesterase inhibition. cAMP and cAMP-mediated PKA-dependent activation of ion channels and Ca2+ cycling proteins drive sarcoplasmic reticulum Ca2+ releases, which, in turn, activate ACs. This feed forward “fail safe” system, kept in check by a high basal phosphodiesterase activity, is central to the generation of normal rhythmic, spontaneous action potentials by pacemaker cells.

Younes, Antoine; Lyashkov, Alexey E.; Graham, David; Sheydina, Anna; Volkova, Maria V.; Mitsak, Megan; Vinogradova, Tatiana M.; Lukyanenko, Yevgeniya O.; Li, Yue; Ruknudin, Abdul M.; Boheler, Kenneth R.; van Eyk, Jennifer; Lakatta, Edward G.

2008-01-01

110

Lithium pacemaker batteries - an overview  

Microsoft Academic Search

Batteries used as power sources in cardiac pacemakers are expected to have high energy density, long storage and operating life and high reliability. They must be nonhazardous under normal operating as well as abusive conditions. Intensive research activities on the past 10-15 years have resulted in the development of a variety of high energy density batteries using Li as the

C. C. Liang; C. F. Holmes

1980-01-01

111

Pacemaker automaticity  

Microsoft Academic Search

The automated measurement of the main electrical parameters of pacemakers, such as battery voltage, current drain, pacing impedance, sensing levels, and pacing thresholds enables a continuous monitoring of the adequate functioning of the implanted device. New technologies in device interrogation, data transfer, and patient alert functions will enhance therapy safety significantly by the immediate detection of all, including transient, device

Joerg Neuzner; Thorsten Schwarz; Johannes Sperzel

2000-01-01

112

Dual chamber pacemaker implants--a new opportunity in Pakistan for children with congenital and acquired complete heart block  

Microsoft Academic Search

Implantation of cardiac pacemakers has been practiced for at least five decades with continuous developments of the hardware. The invention of dual chamber pacemakers has initiated a debate concerning its superiority over single chamber ventricular pacemakers. Throughout the world, surgeons have been using dual chambered permanent pacemakers with successful follow ups. However, Pakistan has not yet taken the advantage of

Awais Ashfaq; Mansoor Ahmed Khan; Mehnaz Atiq; Muhammad Muneer Amanullah

2011-01-01

113

Voltage clamp of bull-frog cardiac pace-maker cells: a quantitative analysis of potassium currents.  

PubMed Central

Spontaneously active single cells have been obtained from the sinus venosus region of the bull-frog, Rana catesbeiana, using an enzymic dispersion procedure involving serial applications of trypsin, collagenase and elastase in nominally 0 Ca2+ Ringer solution. These cells have normal action potentials and fire spontaneously at a rate very similar to the intact sinus venosus. A single suction micro-electrode technique (Hamill, Marty, Neher, Sakmann & Sigworth, 1981; Hume & Giles, 1983) has been used to record the spontaneous diastolic depolarizations or pace-maker activity as well as the regenerative action potentials in these cells. This electrophysiological activity is completely insensitive to tetrodotoxin (TTX; 3 X 10(-6) M) and is very similar to that recorded from an in vitro sinus venosus preparation. The present experiments were aimed at identifying the transmembrane potassium currents, and analysing their role(s) in the development of the pace-maker potential and the repolarization of the action potential. Depolarizing voltage-clamp steps from the normal maximum diastolic potential (-75 mV) elicit a time- and voltage-dependent activation of an outward current. The reversal potential of this current in normal Ringer solution [( K+]0 2.5 mM) is near -95 mV; and it shifts by 51 mV per tenfold increase in [K+]0, which strongly suggests that this current is carried by K+. We therefore labelled it IK. The reversal potential of IK did not shift in the positive direction following very long (20 s) depolarizing clamp steps to +20 mV, indicating that 'extracellular' accumulation of [K+]0 does not produce any significant artifacts. The fully activated instantaneous current-voltage (I-V) relationship for IK is approximately linear over the range of potentials -130 to -30 mV. Thus, the ion transfer mechanism of IK may be described as a simple ohmic conductance in this range of potentials. Positive relative to -30 mV, however, the I-V exhibits significant inward rectification. A Hodgkin-Huxley analysis of the kinetics of IK, including a demonstration that the envelope of tails quantitatively matches the time course of the onset of IK during a prolonged depolarizing clamp step has been completed. The steady-state activation variable (n infinity) of IK spans the voltage range approximately -40 to +10 mV. It is well-fitted by a Boltzmann distribution function with half-activation at -20 mV. The time course of decay of IK is a single exponential. However, the activation or onset of IK shows clear sigmoidicity in the range of potentials from the activation threshold (-40 mV) to 0 mV.(ABSTRACT TRUNCATED AT 400 WORDS) Images PLATE 1 PLATE 2

Giles, W R; Shibata, E F

1985-01-01

114

Electrocautery-induced pacemaker malfunction during surgery  

Microsoft Academic Search

We report a case of electrocautery-induced pacemaker failure that resulted in asystole in a 15-year-old girl scheduled for\\u000a cardiac surgery. Her pacemaker was converted to the asynchronous mode the night before surgery. Electromagnetic interference\\u000a from the unipolar electrocautery caused a reducion in the battery voltage, which allowed the digital circuitry, but not the\\u000a voltage control oscillator (VCO), to work properly.

Devanand Mangar; Glen M. Atlas; Peter B. Kane

1991-01-01

115

Pacemaker explosions in crematoria: problems and possible solutions  

PubMed Central

The number of artificial cardiac pacemakers is increasing, as is the number of bodies being cremated. Because of the explosive potential of pacemakers when heated, a statutory question on the cremation form asks whether the deceased has a pacemaker and if so whether it has been removed. We sent a questionnaire to all the crematoria in the UK enquiring about the frequency, consequences and prevention of pacemaker explosions. We found that about half of all crematoria in the UK experience pacemaker explosions, that pacemaker explosions may cause structural damage and injury and that most crematoria staff are unaware of the explosive potential of implantable cardiac defibrillators. Crematoria staff rely on the accurate completion of cremation forms, and doctors who sign cremation forms have a legal obligation to provide such information.

Gale, Christopher P; Mulley, Graham P

2002-01-01

116

A short history on pacemakers.  

PubMed

Artificial pacemakers have taken part or possibly driven many developments in cardiac science and medicine and are therefore a very important story to remember. This 300-year journey of discovery has been contributed to by experts from across the Globe. The essential foundation of knowledge such as basic electrophysiology and applied electrotherapy was built in the 18th century and is now academically and socially accepted. This line of inventions and research has seen: early use of meta-analyses, the initial coming together of medical or bioengineering and the concept of cardiac monitoring--now a mainstay in the hospital care of a patient. In the 21st century pacemaker developments are no longer solely about reducing mortality but improving morbidity. Design developments reduce: discomfort, additional surgeries and invasive procedures. New energy sources have become lighter, smaller and with a longer life span. PMID:24083883

Ward, Catherine; Henderson, Susannah; Metcalfe, Neil H

2013-11-15

117

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

PubMed

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

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

2011-12-01

118

Analysis of terminal arrhythmias stored in the memory of pacemakers from patients dying suddenly  

Microsoft Academic Search

Aims Stored electrograms or marker channels are available in most of modern cardiac pacemaker models. We sought to analyse these information to uncover terminal events of pacemaker patients dying suddenly. Method and results We made post-mortem pacemaker (PM) interrogations in 19 patients dying suddenly out of hospital between the years 1997 and 2005 (mean age 59+ 13 years, 90% males).

H. Nagele; S. Hashagen; M. Azizi; S. Behrens; M. A. Castel

2007-01-01

119

Cardiac Bioelectricity and Arrhythmias  

NSDL National Science Digital Library

Deep inside a human heart, its pacemaker sends out bursts of electrical signals that keep the heart pumping rhythmically, supplying life-giving oxygen to the body. When these electrical waves become disorganized, the heart starts beating irregularly or arrhythmically. Flavio Fenton and Elizabeth Cherry of Cornell University made this interactive program to provide education on arrhythmias. It presents detailed information on cardiac anatomy, normal cardiac electrophysiology, and different kinds of arrhythmias using a combination of words, pictures, and interactive, computer simulations and animations.

Flavio Fenton (Cornell University;); Elizabeth Cherry (Cornell University;)

2006-09-22

120

Pacemakers and implantable cardioverter defibrillators - general and anesthetic considerations.  

PubMed

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

Rapsang, Amy G; Bhattacharyya, Prithwis

2014-01-01

121

Perceptions of cardiac rehabilitation patients, specialists and rehabilitation programs regarding cardiac rehabilitation wait times  

PubMed Central

Background In 2006, the Canadian Cardiovascular Society (CCS) Access to Care Working Group recommended a 30-day wait time benchmark for cardiac rehabilitation (CR). The objectives of the current study were to: (1) describe cardiac patient perceptions of actual and ideal CR wait times, (2) describe and compare cardiac specialist and CR program perceptions of wait times, as well as whether the recommendations are appropriate and feasible, and (3) investigate actual wait times and factors that CR programs perceive to affect these wait times. Methods Postal and online surveys to assess perceptions of CR wait times were administered to CR enrollees at intake into 1 of 8 programs, all CCS member cardiac specialists treating patients indicated for CR, and all CR programs listed in Canadian directories. Actual wait times were ascertained from the Canadian Cardiac Rehabilitation Registry. The design was cross-sectional. Responses were described and compared. Results Responses were received from 163 CR enrollees, 71 cardiac specialists (9.3% response rate), and 92 CR programs (61.7% response rate). Patients reported that their wait time from hospital discharge to CR initiation was 65.6?±?88.4?days (median, 42?days), while their ideal median wait time was 28?days. Most patients (91.5%) considered their wait to be acceptable, but ideal wait times varied significantly by the type of cardiac indication for CR. There were significant differences between specialist and program perceptions of the appropriate number of days to wait by most indications, with CR programs perceiving shorter waits as appropriate (p?programs reported that feasible wait times were significantly longer than what was appropriate for all indications (p?program initiation was 64?days (mean, 80.0?±?62.8?days), with no difference in wait by indication. Conclusions Wait times following access to cardiac rehabilitation are prolonged compared with consensus recommendations, and yet are generally acceptable to most patients. Wait times following percutaneous coronary intervention in particular may need to be shortened. Future research is required to provide an evidence base for wait time benchmarks.

2012-01-01

122

Transtelephonic monitoring of 25,919 implanted pacemakers.  

PubMed

In order to evaluate the behavior of lithium-powered cardiac pacemakers, a database of 25,919 lithium-powered pacing systems including 23,517 single and 2,402 dual chambered pacemaker generators were followed in 21,750 patients. Of this group, 11,319 were currently active in addition to 7,560 who died, as well as 2,871 patients who terminated their follow-up service prior to the end-of-life of the pacemaker system. A total of 23,517 single chambered pacemakers were followed for 719,173 months of pacing. The mean time to explant for generator malfunctions was 42 months and for all pacing system malfunctions it was 38 months compared to 31.9 months and 28.6 months, respectively, for the 2,402 dual chambered units that were observed for 38,718 months. In the single chambered units, the most frequent reason for explant was battery exhaustion (37% of explants) followed by lead problems (26%) compared to 49% and 12%, respectively, for the dual chambered units. The incidence rates, defined as a transtelephonic test result, required physician decision for action or clarification of the pacing mode or program parameters and showed a high incidence rate immediately post-implant; thereafter, there was a relatively trouble-free period until the 36th month when capture, sensing, and battery problems began to occur at a steady rate reaching 4% at the end of 48 months. Similarly, for dual chambered units, an 8% incidence rate was seen within the first 3 months, followed by a quiescent period until the 28th month when the incidence rate jumped to 16%.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2423978

Dreifus, L S; Zinberg, A; Hurzeler, P; Puziak, A D; Pennock, R; Feldman, M; Morse, D P

1986-05-01

123

[Anaerobic threshold in the evaluation of heart function in patients with rate-responsive pacemaker].  

PubMed

It is very difficult to evaluate the ability of carrying out physical exercise in patients with rate responsive (RR) pacemaker (PM). However, the anaerobic threshold (AT) proved to be a useful parameter in the evaluation of cardiac function. The AT can be easily reproduced and not influenced from emotional aspects of both the patient and the physician, moreover being under maximum and then easy to achieve. Aims of our study were: to evaluate if the cardiopulmonary stress test can represent a method to be used for a more correct rate responsive pacemaker programming; to compare the data obtained of 3 rate responsive pacemakers steered by different sensors. We have studied 24 patients, of whom 10 with Activitrax (A), 8 with Meta (M), and 6 with Phymos MPT (P) pacemakers. Patients were submitted to symptoms limited cycloergometer stress test at 2 different settings: fixed rate at 70 b/min; increasing rate at until 85% of maximum heart rate for each patient, with range 0 + 10 W/min. Gas exchange data were continuously collected using an automated system (Medical Graphic System 2001) based on Whipp and Wasserman's method.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1799896

Santomauro, M; Romano, M; Pappone, C; Ferraro, S; Fazio, S; Maddalena, G; Damiano, M; Chiariello, M

1991-08-01

124

An intelligent system for pacemaker reprogramming.  

PubMed

The process of reprogramming a cardiac pacemaker can be described in terms similar to those used for describing diagnostic problem solving. In this paper, the process of reprogramming a pacemaker is formalized as a special form of abductive diagnostic reasoning, where observable findings are interpreted with respect to results obtained from diagnostic tests. The dynamics of this process is cast as a diagnostic strategy, where information is gathered in a structured fashion. This abductive theory of pacemaker reprogramming has been used as the basis for an actual system that in its present form is capable of assisting cardiologists in dealing with problems in atrial sensing and pacing. The performance of the system has been evaluated using data from actual patients. PMID:10564843

Lucas, P J; Tholen, A; van Oort, G

1999-11-01

125

MRI-conditional pacemakers: current perspectives  

PubMed Central

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

Ferreira, Antonio M; Costa, Francisco; Tralhao, Antonio; Marques, Hugo; Cardim, Nuno; Adragao, Pedro

2014-01-01

126

Cardiac pacing--from then to now.  

PubMed

Progress in both the health sciences and engineering sciences has been necessary for the development of the cardiac pacemaker. From the invention of the vacuum tube triode amplifier in 1906 to that of the oscillator just a few years later; from the early electrocardiograph in 1906 and the first stimulation of a dog's heart in 1927 to the application of electricity to the heart of a stillborn infant only 2 years later, engineering and medicine have progressed together to solve problems in pacemakers. The semiconductor transistor emerged in 1948, and in 1950 work was published on the open heart resuscitation of dogs with voltage pulses to the heart, work whose principle was applied soon after in a human patient with complete heart block. The development of the modern pacemaker has run an exciting course, including such phenomena as one engineer helping to design his own pacemaker. In the past 20 years, science has change the package, the power source, pacing mode, electrodes, and leads of pacemakers; it has improved their reliability and longevity, their programming, telemetry, and instrumentation. PMID:6369090

Gold, R D

1984-01-01

127

Pneumopericardium: an uncommon complication of atrial lead perforation following pacemaker implantation.  

PubMed

Cardiac perforation is an infrequent but potentially life-threatening complication of pacemaker implantation. We report a case of right atrial lead perforation complicated by pneumopericardium shortly after pacemaker lead insertion. Transthoracic echocardiography revealed no evidence of pericardial effusion and pacemaker lead displacement, but a thoracic computed tomography scan illustrated the lead course and confirmed the diagnosis. This case suggests that computed tomography is a sensitive modality to confirm the diagnosis at the early stage of this complication. PMID:24783478

Higny, Julien; Blommaert, Dominique

2014-04-01

128

21 CFR 870.3670 - Pacemaker charger.  

Code of Federal Regulations, 2010 CFR

...Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker charger is a device used transcutaneously to recharge the batteries of a rechargeable pacemaker. (b) Classification....

2012-04-01

129

21 CFR 870.3670 - Pacemaker charger.  

Code of Federal Regulations, 2010 CFR

...Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker charger is a device used transcutaneously to recharge the batteries of a rechargeable pacemaker. (b) Classification....

2010-04-01

130

21 CFR 870.3670 - Pacemaker charger.  

Code of Federal Regulations, 2010 CFR

...Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker charger is a device used transcutaneously to recharge the batteries of a rechargeable pacemaker. (b) Classification....

2011-04-01

131

SCN5A and sinoatrial node pacemaker function  

Microsoft Academic Search

The SCN5A gene encodes specific voltage-dependent Na+ channels abundant in cardiac muscle that open and close at specific stages of cardiac activity in response to voltage change, thereby controlling the magnitude and timecourse of voltage-dependent Na+ currents (iNa )i n cardiac muscle cells. Although iNa has been recorded from sinoatrial (SA) node pacemaker cells, its precise role in SA node

Ming Lei; Henggui Zhang; Andrew A. Grace; H. Huang

2007-01-01

132

Electromagnetic Interference on Pacemakers  

PubMed Central

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

Erdogan, Okan

2002-01-01

133

Pacemaker and radiotherapy in breast cancer: is targeted intraoperative radiotherapy the answer in this setting?  

PubMed Central

We present the case of an 83?year old woman with a cardiac pacemaker located close in distance to a subsequently diagnosed invasive ductal carcinoma of the left breast. Short range intraoperative radiotherapy was given following wide local excision and sentinel node biopsy. The challenges of using ionising radiation with pacemakers is also discussed.

2012-01-01

134

Cardiac Rehabilitation Programs. Number 3. Health Technology Assessment Reports, 1991.  

National Technical Information Service (NTIS)

Cardiac rehabilitation is a continuing process whereby patients with cardiac disease are encouraged to achieve their maximal functional capacity and attain acceptable psychological, social, emotional, vocational, and economic status. Cardiac rehabilitatio...

S. S. Hotta

1991-01-01

135

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.

136

Pacemaker lead endocarditis  

PubMed Central

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

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

2003-01-01

137

Magnetic Resonance Imaging Conditional Pacemakers: Rationale, Development and Future Directions  

PubMed Central

Pacemakers and other cardiac implantable electronic devices (CIEDs) have long been considered an absolute contraindication to magnetic resonance imaging (MRI), a crucial and growing imaging modality. In the last 20 years, protocols have been developed to allow MR scanning of CIED patients with a low complication rate. However, this practice has remained limited to a relatively small number of centers, and many pacemaker patients continue to be denied access to clinically indicated imaging. The introduction of MRI conditional pacemakers has provided a widely applicable and satisfactory solution to this problem. Here, the interactions of pacemakers with the MR environment, the results of MR scanning in patients with conventional CIEDs, the development and clinical experience with MRI conditional devices, and future directions are reviewed.

Cronin, Edmond M; Wilkoff, Bruce L

2012-01-01

138

Clinical testing of implanted pacemakers  

Microsoft Academic Search

The function of implanted pacemakers was assessed at a special pacemaker clinic at intervals of three to six months. Measurements of the basic discharge rate of the pacemaker were made and the waveform was recovered from skin electrodes and displayed on an oscilloscope screen. The impulse was photographed from the screen and subsequent waveform analysis was carried out. Reproducible results

Edgar Sowton; Kenneth Gray

1971-01-01

139

Triboelectric simulation of pacemaker malfunction.  

PubMed

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

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

2002-07-01

140

Triboelectric simulation of pacemaker malfunction  

Microsoft Academic Search

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

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

2002-01-01

141

A Rare Instance of ‘CardioRespiratory Pacing’: Permanent Pacemaker Insertion for Symptomatic Bradycardia in a Quadriplegic Man Dependent on Diaphragmatic Pacing by Phrenic Nerve Stimulators  

Microsoft Academic Search

Patients with high spinal cord injury may present with significant cardiac dysautonomia. There is a dearth of data regarding electromechanical interference to cardiac pacemakers from phrenic nerve stimulators which are used in such patients for respiratory support. We report an instance of bipolar lead permanent pacemaker insertion for ventricular standstill in a man with quadriplegia following C2 fracture and the

Unni Krishnan; Punit S. Ramrakha; Andrew Money-Kyrle

2010-01-01

142

Nkx2.5-negative myocardium of the posterior heart field and its correlation with podoplanin expression in cells from the developing cardiac pacemaking and conduction system.  

PubMed

Recent advances in the study of cardiac development have shown the relevance of addition of myocardium to the primary myocardial heart tube. In wild-type mouse embryos (E9.5-15.5), we have studied the myocardium at the venous pole of the heart using immunohistochemistry and 3D reconstructions of expression patterns of MLC-2a, Nkx2.5, and podoplanin, a novel coelomic and myocardial marker. Podoplanin-positive coelomic epithelium was continuous with adjacent podoplanin- and MLC-2a-positive myocardium that formed a conspicuous band along the left cardinal vein extending through the base of the atrial septum to the posterior myocardium of the atrioventricular canal, the atrioventricular nodal region, and the His-Purkinje system. Later on, podoplanin expression was also found in the myocardium surrounding the pulmonary vein. On the right side, podoplanin-positive cells were seen along the right cardinal vein, which during development persisted in the sinoatrial node and part of the venous valves. In the MLC-2a- and podoplanin-positive myocardium, Nkx2.5 expression was absent in the sinoatrial node and the wall of the cardinal veins. There was a mosaic positivity in the wall of the common pulmonary vein and the atrioventricular conduction system as opposed to the overall Nkx2.5 expression seen in the chamber myocardium. We conclude that we have found podoplanin as a marker that links a novel Nkx2.5-negative sinus venosus myocardial area, which we refer to as the posterior heart field, with the cardiac conduction system. PMID:17441204

Gittenberger-de Groot, Adriana C; Mahtab, Edris A F; Hahurij, Nathan D; Wisse, Lambertus J; Deruiter, Marco C; Wijffels, Maurits C E F; Poelmann, Robert E

2007-01-01

143

Pacemakers (Beyond the Basics)  

MedlinePLUS

... electronic devices Modes of cardiac pacing: Nomenclature and selection Pacing system malfunction: Evaluation and management Patient information: ... electronic devices Modes of cardiac pacing: Nomenclature and selection Pacing system malfunction: Evaluation and management Temporary cardiac ...

144

Bioartificial Sinus Node Constructed via In Vivo Gene Transfer of an Engineered Pacemaker HCN Channel Reduces the Dependence on Electronic Pacemaker in a Sick-Sinus Syndrome Model  

Microsoft Academic Search

Background—The normal cardiac rhythm originates in the sinoatrial (SA) node that anatomically resides in the right atrium. Malfunction of the SA node leads to various forms of arrhythmias that necessitate the implantation of electronic pacemakers. We hypothesized that overexpression of an engineered HCN construct via somatic gene transfer offers a flexible approach for fine-tuning cardiac pacing in vivo. Methods and

Hung-Fat Tse; Tian Xue; Chu-Pak Lau; Chung-Wah Siu; Kai Wang; Qing-Yong Zhang; Gordon F. Tomaselli; Fadi G. Akar; Ronald A. Li

145

69 FR 28196 - Medicare Program; Proposed Changes to the Hospital Inpatient Prospective Payment Systems and...  

Federal Register 2010, 2011, 2012, 2013

...Other Heart Assist System Implant) (proposed title change...Permanent Cardiac Pacemaker Implant with Acute Myocardial Infarction...Permanent Cardiac Pacemaker Implant). Movement of the procedure...failure, to the list of major problems under DRG 387...

2004-05-18

146

Optogenetic control of cardiac function.  

PubMed

The cardiac pacemaker controls the rhythmicity of heart contractions and can be substituted by a battery-operated device as a last resort. We created a genetically encoded, optically controlled pacemaker by expressing halorhodopsin and channelrhodopsin in zebrafish cardiomyocytes. Using patterned illumination in a selective plane illumination microscope, we located the pacemaker and simulated tachycardia, bradycardia, atrioventricular blocks, and cardiac arrest. The pacemaker converges to the sinoatrial region during development and comprises fewer than a dozen cells by the time the heart loops. Perturbation of the activity of these cells was entirely reversible, demonstrating the resilience of the endogenous pacemaker. Our studies combine optogenetics and light-sheet microscopy to reveal the emergence of organ function during development. PMID:21071670

Arrenberg, Aristides B; Stainier, Didier Y R; Baier, Herwig; Huisken, Jan

2010-11-12

147

[Antibiotic prophylaxis in the implantation of permanent pacemakers].  

PubMed

Prophylactic antibiotics are prescribed frequently at pacemaker placements despite a paucity of data indicating effectiveness. Battery pack replacement procedures usually are not followed by infections and prophylactic antibiotics in this setting are controversial. Pacing wire and battery pack placement have higher infection rate (about 5%), thus antibiotics may be useful in the prevention of serious infections. In this study three different schemes of antibiotics prophylaxis (local prophylaxis, Short term prophylaxis, conventional postoperative prophylaxis) were compared in 72 patients receiving permanent transvenous cardiac pacemakers. No significant differences were found among these three groups also if S.T.P. showed a greatest simplicity. PMID:7145197

Ucchino, S; Francomano, F; D'Aulerio, A; Di Iorio, C; Marulli, P; Di Gregorio, P

1982-11-17

148

Nursing: Access to Rural Cardiac Rehabilitation Programs. Abstract, Executive Summary, Final Report and Appendices.  

National Technical Information Service (NTIS)

The purpose of this descriptive-longitudinal study was to describe the factors that influence the use of cardiac rehabilitation programs by rural adults who have experienced a myocardial infarction and/or undergone angioplasty or coronary artery bypass su...

J. E. Johnson C. Weinert J. Richardson

1995-01-01

149

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

PubMed

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

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

2014-01-01

150

A Microcalorimeter for Nondestructive Analysis of Pacemakers and Pacemaker Batteries  

Microsoft Academic Search

A microcalorimeter has been built by the authors and used to measure internal losses in primary pacemaker batteries. Power dissipation of 10-50 ¿W has been measured in new pacemaker batteries, much of which is traceable to innocuous exotherm from continuing curing of plastic materials in the battery. True internal shorts have produced 1000-2000 ¿W of heat. Present noise level is

Wilson Greatbatch; Robert McLean; William Holmes; Curtis Holmes

1979-01-01

151

Cardiac Catheterization Experience in Hospitals Without Cardiovascular Surgery Programs.  

National Technical Information Service (NTIS)

With the increase in coronary bypass surgery since the development of selective coronary arteriography, there has been an increase in the number of arteriograms done and a proliferation of cardiac diagnostic facilities. But the appropriate location of suc...

C. E. Hansing K. Hammermeister K. Prindle R. Twiss R. R. Schwindt

1978-01-01

152

Neutron Radiography of Cardiac Pacemaker Batteries.  

National Technical Information Service (NTIS)

This citation summarizes a one-page announcement of technology available for utilization. In a project funded by the Food and Drug Administration, scientists at the National Bureau of Standards are investigating one of the phenomena which occurs as cardia...

1981-01-01

153

Implementing a cardiac resynchronization therapy program in a county hospital.  

PubMed

Clinical trials and research literature show the benefits of cardiac resynchronization therapy and implantable cardioverter defibrillator devices in improving the quality of life for selected patients with heart failure. While translating these positive research results into clinical practice is a major effort requiring a strategic planning process, implementing these practices in-house may result in cost savings and possible increased revenue. The authors describe the planning and implementation process used to introduce these therapies in a cardiac catheterization laboratory at a county teaching hospital. PMID:16200008

Merchant, Karen; Laborde, Ann

2005-09-01

154

Cardiac Rehabilitation Patient and Organizational Factors: What Keeps Patients in Programs?  

PubMed Central

Background Despite documented benefits of cardiac rehabilitation, adherence to programs is suboptimal with an average dropout rate of between 24% and 50%. The goal of this study was to identify organizational and patient factors associated with cardiac rehabilitation adherence. Methods and Results Facilities of the Wisconsin Cardiac Rehabilitation Outcomes Registry Project (N=38) were surveyed and records of 4412 enrolled patients were analyzed. Generalized estimating equations were used to account for clustering of patients within facilities. The results show that organizational factors associated with significantly increased adherence were relaxation training and diet classes (group and individual formats) and group?based psychological counseling, medication counseling, and lifestyle modification, the medical director's presence in the cardiac rehabilitation activity area for ?15 min/week, assessment of patient satisfaction, adequate space, and adequate equipment. Patient factors associated with significantly increased adherence were aged ?65 years, the American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR) high?risk category, having received coronary artery bypass grafting, and diabetes disease. Non?white race was negatively associated with adherence. There was no significant gender difference in adherence. None of the baseline patient clinical profiles were associated with adherence including body mass index, total cholesterol, low?density lipoprotein, high?density lipoprotein, triglycerides, and blood pressure. Conclusions Factors associated with adherence to cardiac rehabilitation included both organizational and patient factors. Modifiable organizational factors may help directors of cardiac rehabilitation programs improve patient adherence to this beneficial program.

Turk-Adawi, Karam I.; Oldridge, Neil B.; Tarima, Sergey S.; Stason, William B.; Shepard, Donald S.

2013-01-01

155

1978 Pacemaker Newspaper Awards: What Makes a Pacemaker?  

ERIC Educational Resources Information Center

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

Brasler, Wayne

1979-01-01

156

Cardiac arrhythmias during exercise testing in healthy men.  

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

157

Client perceptions of a rural-based cardiac rehabilitation program: a grounded theory approach.  

PubMed

A grounded theory approach was used in an attempt to generate theory about client perceptions and experiences of a cardiac rehabilitation program conducted in a rural community. A series of interviews was conducted with a selection of people who had experienced a life-threatening cardiac event. The cohort was divided into two groups: those who attended a cardiac rehabilitation program and those who did not. The findings, though not generalisable, allowed the generation of a number of theories (which may come to be the genesis of future research) regarding the differences in the physiological, psychological, sociological and vocational well-being between the groups. The findings also suggested that location of the program, the times it was conducted, and the communication skills of significant healthcare workers who recruited participants were important factors affecting attendance. PMID:9708091

Thornhill, M; Stevens, J A

1998-05-01

158

Magnetic Resonance Imaging in a Patient with a Dual Chamber Pacemaker  

PubMed Central

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

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

2010-01-01

159

Hydrogen-induced microelectronic capacitor failure in pacemakers.  

PubMed

Ceramic chip capacitors used in hybrid microelectronics for cardiac pacemakers are usually highly reliable. However, under certain conditions of capacitor construction, capacitor materials, mounting techniques, and environmental conditions, high failure rates may occur. A specific example is presented in which a ceramic capacitor used in an implanted pacemaker delaminated and failed approximately 30 days after being implanted. The failed capacitor caused a pulse rate rise, but due to circuit design techniques, the rate increase was limited to an acceptable value. The capacitor that failed was from an isolated lot of capacitors that was manufactured using pure palladium plates. The circuit containing this capacitor was hermetically sealed within a titanium case by welding. During the welding, a small amount of hydrogen was released from the titanium which, over a period of 2 to 4 weeks, was absorbed by the palladium plates in the capacitor. By absorbing the hydrogen, the palladium plates exhibit a volumetric expansion of sufficient magnitude to crack and delaminate the capacitor to the point of failure. Subsequently, the recurrence of this failure mode has been avoided by using capacitors containing special palladium alloys that cannot absorb hydrogen. This phenomenon is of interest to pacemaker designers since mercury batteries used in conventional pacemakers generate large amounts of hydrogen and potentially may be responsible for complications when used in conjunction with capacitors containing palladium. PMID:958043

Rainer, W G; Kolenik, S A; Whittaker, R E; Sadler, T R; Lapin, E S

1976-01-01

160

VideoLab: Optogenetic Pacemaker  

NSDL National Science Digital Library

In mammals, the heart's primary pacemaker lies in a specialized group of cells -- but do non-mammalian vertebrates have a similar control system? To find out, Arrenberg et al. genetically engineered zebrafish to express light-sensitive proteins, and then used light beams generated with a digital micromirror device to locate and manipulate the function of the pacemaker cells in the hearts of zebrafish embryos -- capturing the action on high-speed video.

Aristides B. Arrenberg (University of California; University of Freiburg;Department of Physiology; Institute of Biology); Didier Y. R. Stainier (University of California;Department of Biochemistry and Biophysics and Cardiovascular Research Institute); Herwig Baier (University of California;Department of Physiology); Jan Huisken (University of California; Max Planck Institute of Molecular Cell Biology and Genetics;Department of Biochemistry and Biophysics and Cardiovascular Research Institute)

2010-11-12

161

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

PubMed Central

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

Li, RA

2012-01-01

162

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

PubMed

Normal rhythms originate in the sino-atrial node, a specialized cardiac tissue consisting of only a few thousands of nodal pacemaker cells. Malfunction of pacemaker cells due to diseases or aging leads to rhythm generation disorders (for example, bradycardias and sick-sinus syndrome (SSS)), which often necessitate the implantation of electronic pacemakers. Although effective, electronic devices are associated with such shortcomings as limited battery life, permanent implantation of leads, lead dislodging, the lack of autonomic responses and so on. Here, various gene- and cell-based approaches, with a particular emphasis placed on the use of pluripotent stem cells and the hyperpolarization-activated cyclic nucleotide-gated-encoded pacemaker gene family, that have been pursued in the past decade to reconstruct bio-artificial pacemakers as alternatives will be discussed in relation to the basic biological insights and translational regenerative potential. PMID:22673497

Li, R A

2012-06-01

163

Ventricular pacing on the prognosis of patients with pacemaker implantation.  

PubMed

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

Zheng, Liuying; Du, Xinping

2014-06-01

164

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

ERIC Educational Resources Information Center

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

Jenny, Ng Yuen Yee; Fai, Tam Sing

2001-01-01

165

[Clinical competence in intensive cardiac care units: from practical needs to training programs].  

PubMed

Since the early 1970s, intensive cardiac care is applied in coronary care units (CCUs), initially developed to treat lethal arrhythmias in patients with acute myocardial infarction. In the last decades, treatments offered within the CCUs have greatly expanded. Thus, these units have been called intensive cardiac care units (ICCUs) to reflect such evolution of care and the different epidemiology of patients admitted (subjects with acute coronary syndromes, acute and advanced heart failure, rhythm disturbances or severe valve dysfunction). At the same time, new drugs have become available but also different diagnostic, interventional and therapeutic procedures have been developed, resulting in better patient treatment and improved outcomes. These new devices require a high degree of specialization and specific skills that not every cardiologist is always used to. Consequently, specific training programs on intensive cardiac care for cardiologists working in ICCUs are clearly warranted. The present paper describes the advanced training programs on intensive cardiac care endorsed by the European Society of Cardiology and the Italian Association of Hospital Cardiologists (ANMCO). Both projects aim at improving current knowledge and skills of intensive cardiologists on specific pharmacologic and technical procedures, extending the competence of trained cardiologists to the management of critically ill cardiac patients, and uniforming the quality of care in any ICCU. PMID:20380336

Fradella, Giuseppe; De Luca, Leonardo; Tubaro, Marco; Lettino, Maddalena; Conte, Maria Rosa; Geraci, Giovanna; Casella, Gianni

2010-01-01

166

Pregnancy in sick sinus syndrome with pacemaker - two cases.  

PubMed

Sick sinus syndrome is a generalized abnormality of cardiac impulse formation that may be caused by extrinsic causes or by intrinsic disease of the sinus node making it unable to perform pace making function. It can be manifested for the first time in pregnancy. First case was diagnosed as sick sinus syndrome at 8 weeks of gestation having Mobitz type I heart block (Wenckebach block), and needed temporary pacemaker during caesarean section. Second case was diagnosed at 24 weeks of gestation having complete heart block and needed permanent pacemaker at 38 weeks of gestation due to exaggeration of the symptoms. Both the cases were dealt successfully by caesarean section under general anesthesia in close collaboration with cardiologists and anesthesiologists. PMID:23715370

Parveen, T; Begum, F; Akhter, N; Sharmin, F

2013-04-01

167

[Pacemaker-Twiddler's Syndrome (author's transl)].  

PubMed

A case of Pacemaker-Twiddler's Syndrome is presented. Rotation of a permanent pacemaker can result in a capstan effect, and the lead is drawn out of the right ventricle. Fixing thouroughly the pacemaker and the lead should be an useful prophylactic measure. PMID:723748

Kolb, P; Kauffmann, P

1978-11-24

168

Reversible Prolonged Pacemaker Failure Due to Electrocautery  

Microsoft Academic Search

Despite improved technology, permanent pacemakers remain susceptible to electromagnetic interference, including electrocautery. We describe sudden, apparently irreversible output loss in a pacemaker associated with the use of electrocautery, despite standard precautionary measures. When tested by the manufacturer several weeks later, pulse generator function was normal and it was functioning in the “reset” mode. We postulate that pacemaker failure was related

Robert W. Peters; Michael R. Gold

1998-01-01

169

Sick sinus syndrome in a dog: Treatment with dual-chambered pacemaker implantation  

PubMed Central

A 2-year-old male castrated boxer dog was presented because of a history of syncope. Electrocardiogram tracings obtained with a cardiac event monitor showed bradycardia culminating in asystole. Sick sinus syndrome was diagnosed and treated with transvenous implantation of a dual-chambered permanent pacemaker.

Burrage, Heather

2012-01-01

170

Interference of Cellular Phones and Metal Detectors With Pacemakers and ICDs: Still a Problem?  

Microsoft Academic Search

Electromagnetic interference (EMI) may affect the behaviour of some medical electrical equipment, including cardiac pacemakers and implanted cardioverter-defibrillators (ICDs) [1]. EMI occurs when an electronic device is subjected to any electromagnetic field with an amplitude higher than the interference threshold. The effects on the device depend on the energy of the electromagnetic signal interfering with the normal function of the

E. Occhetta; L. Plebani; M. Bortnik; P. Marino

171

Rheumatoid pericardial effusion with heart block treated by pericardiectomy and implantation of permanent pacemaker.  

PubMed Central

A patient with long-standing seropositive erosive rheumatoid arthritis developed a pericardial effusion with chronic cardiac tamponade. He had evidence of conducting system disease and developed heart block. He was successfully treated by pericardiectomy and implantation of a demand pacemaker.

Gelson, A; Sanderson, J M; Carson, P

1977-01-01

172

Pacemaker interference and low-frequency electric induction in humans by external fields and electrodes  

Microsoft Academic Search

The possibility of interference by low-frequency external electric fields with cardiac pacemakers is a matter of practical concern. For pragmatic reasons, experimental investigations into such interference have used contact electrode current sources. However, the applicability to the external electric field problem remains unclear. The recent development of anatomically based electromagnetic models of the human body, together with progress in computational

Trevor W. Dawson; Maria A. Stuchly; Kris Caputa; Antonio Sastre; Richard B. Shepard; Robert Kavet

2000-01-01

173

Pacemaker/implantable cardioverter-defibrillator interaction.  

PubMed

We describe a case of pacemaker/implantable cardioverter-defibrillator (ICD) interaction in a single system causing failure to detect induced ventricular fibrillation (VF) in an 83-year-old man with ischemic cardiomyopathy. He underwent an ICD generator replacement due to battery depletion. In addition, a right atrial lead was placed to treat symptomatic bradycardia. Appropriate sensing and pacing parameters were observed in both leads during implant, and there was no cross-talk between the leads. A defibrillation threshold (DFT) test was performed (sense 1.5 mV, shock on T) with induction of VF that was not detected by the device, ultimately requiring an external defibrillation to terminate the arrhythmia. The device printout during testing showed atrial/ventricular lead cross-talk caused by the 1.1-J shock to induce VF, sensed beats in the noise window activating the noise suppression algorithm and preventing initial VF detection, and recurrent resetting of the automatic gain control due to ventricular sensing of the atrial pacing artifact preventing detection and perpetuating atrioventricular (AV) pacing at a rate of 60 bpm. In conclusion, pacemaker/ICD interaction can occur in a dual-chamber ICD system. This can be prevented by programming a shorter AV delay, increasing sensitivity (i.e., more sensitive value), and programming a pause before initiating pacing after an ICD discharge. PMID:20382269

Jimenez, Alejandro; Dickfeld, Timm; Saliaris, Anastasios; Shorofsky, Stephen

2010-08-01

174

Pacemaking kisspeptin neurons.  

PubMed

Kisspeptin (Kiss1) neurons are vital for reproduction. Gonatotrophin-releasing hormone (GnRH) neurons express the kisspeptin receptor (GPR54), and kisspeptins potently stimulate the release of GnRH by depolarizing and inducing sustained action potential firing in GnRH neurons. As such, Kiss1 neurons may be the presynaptic pacemaker neurons in the hypothalamic circuitry that controls reproduction. There are at least two different populations of Kiss1 neurons; one in the rostral periventricular area (RP3V) that is stimulated by oestrogens and the other in the arcuate nucleus that is inhibited by oestrogens. How each of these Kiss1 neuronal populations participates in the regulation of the reproductive cycle is currently under intense investigation. Based on electrophysiological studies in the guinea-pig and mouse, Kiss1 neurons in general are capable of generating burst-firing behaviour. Essentially, all Kiss1 neurons, which have been studied thus far in the arcuate nucleus, express the ion channels necessary for burst firing, which include hyperpolarization-activated, cyclic nucleotide-gated cation (HCN) channels and the T-type calcium (Cav3.1) channels. In voltage-clamp conditions, these channels produce distinct currents that can generate burst-firing behaviour in current-clamp conditions. The future challenge is to identify other key channels and synaptic inputs involved in the regulation of the firing properties of Kiss1 neurons and the physiological regulation of the expression of these channels and receptors by oestrogens and other hormones. The ultimate goal is to understand how Kiss1 neurons control the different phases of GnRH neurosecretion, hence reproduction. PMID:23884368

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

2013-11-01

175

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

SciTech Connect

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.

Kirova, Youlia M., E-mail: youlia.kirova@curie.net [Department of Radiation Oncology, Institut Curie, Paris (France); Menard, Jean; Chargari, Cyrus; Mazal, Alejandro [Department of Radiation Oncology, Institut Curie, Paris (France); Kirov, Krassen [Department of Anesthesiology and Reanimation, Institut Curie, Paris (France)

2012-07-01

176

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

PubMed

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. PMID:22209162

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

2012-01-01

177

[Wide QRS tachycardia preceded by pacemaker spikes].  

PubMed

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

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

2014-04-01

178

Electrical interference in non-competitive pacemakers  

PubMed Central

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

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

1970-01-01

179

Y2K: Effects on pacemaker and implantable defibrillator programmers  

Microsoft Academic Search

All permanent pacemakers and implantable defibrillators (PPM\\/ICDs) will continue to function as programmed without regard to the date in the year 2000 (Y2K). All manufacturers contacted reassured us that some of these devices incorporate a day\\/year clock in the circuitry; however, these are not involved in sensing or delivering programmed therapy. Some manufacturers’ device programmers will roll over to the

Dennis P. Flynn; James P. Daubert; David T. Huang; Celeste M. Ocampo; Erin O’Gorman

1999-01-01

180

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

PubMed Central

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

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

2013-01-01

181

Percutaneous Extraction of Transvenous Permanent Pacemaker/Defibrillator Leads  

PubMed Central

Background. Widespread use of cardiovascular implantable electronic devices has inevitably increased the need for lead revision/replacement. We report our experience in percutaneous extraction of transvenous permanent pacemaker/defibrillator leads. Methods. Thirty-six patients admitted to our centre from September 2005 through October 2012 for percutaneous lead extraction were included. Lead removal was attempted using Spectranetics traction-type system (Spectranetics Corp., Colorado, CO, USA) and VascoExtor countertraction-type system (Vascomed GmbH, Weil am Rhein, Germany). Results. Lead extraction was attempted in 59 leads from 36 patients (27 men), mean ± SD age 61 ± 5 years, with permanent pacemaker (n = 25), defibrillator (n = 8), or cardiac resynchronisation therapy (n = 3) with a mean ± SD implant duration of 50 ± 23 months. The indications for lead removal included pocket infection (n = 23), endocarditis (n = 2), and ventricular (n = 10) and atrial lead dysfunction (n = 1). Traction device was used for 33 leads and countertraction device for 26 leads. Mean ± SD fluoroscopy time was 4 ± 2 minutes/lead for leads implanted <48 months (n = 38) and 7 ± 3 minutes/lead for leads implanted >48 months (n = 21), P = 0.03. Complete procedural success rate was 91.7% and clinical procedural success rate was 100%, while lead procedural success rate was 95%. Conclusions. In conclusion, percutaneous extraction of transvenous permanent pacemaker/defibrillator leads using dedicated removal tools is both feasible and safe.

Paraskevaidis, Stylianos; Mantziari, Lilian; Megarisiotou, Athanasia; Karvounis, Charalambos

2014-01-01

182

Percutaneous extraction of transvenous permanent pacemaker/defibrillator leads.  

PubMed

Background. Widespread use of cardiovascular implantable electronic devices has inevitably increased the need for lead revision/replacement. We report our experience in percutaneous extraction of transvenous permanent pacemaker/defibrillator leads. Methods. Thirty-six patients admitted to our centre from September 2005 through October 2012 for percutaneous lead extraction were included. Lead removal was attempted using Spectranetics traction-type system (Spectranetics Corp., Colorado, CO, USA) and VascoExtor countertraction-type system (Vascomed GmbH, Weil am Rhein, Germany). Results. Lead extraction was attempted in 59 leads from 36 patients (27 men), mean ± SD age 61 ± 5 years, with permanent pacemaker (n = 25), defibrillator (n = 8), or cardiac resynchronisation therapy (n = 3) with a mean ± SD implant duration of 50 ± 23 months. The indications for lead removal included pocket infection (n = 23), endocarditis (n = 2), and ventricular (n = 10) and atrial lead dysfunction (n = 1). Traction device was used for 33 leads and countertraction device for 26 leads. Mean ± SD fluoroscopy time was 4 ± 2 minutes/lead for leads implanted <48 months (n = 38) and 7 ± 3 minutes/lead for leads implanted >48 months (n = 21), P = 0.03. Complete procedural success rate was 91.7% and clinical procedural success rate was 100%, while lead procedural success rate was 95%. Conclusions. In conclusion, percutaneous extraction of transvenous permanent pacemaker/defibrillator leads using dedicated removal tools is both feasible and safe. PMID:24971363

Paraskevaidis, Stylianos; Konstantinou, Dimitrios; Vassilikos, Vassilios; Theofilogiannakos, Efstratios; Mantziari, Lilian; Megarisiotou, Athanasia; Galitsianos, Ioannis; Karvounis, Charalambos

2014-01-01

183

21 CFR 870.3650 - Pacemaker polymeric mesh bag.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870.3650...Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to...

2009-04-01

184

21 CFR 870.3650 - Pacemaker polymeric mesh bag.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870.3650...Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to...

2010-04-01

185

21 CFR 870.3640 - Indirect pacemaker generator function analyzer.  

Code of Federal Regulations, 2010 CFR

...function analyzer is an electrically powered device that is used to determine pacemaker function or pacemaker battery function by periodically monitoring an implanted pacemaker's pulse rate and pulse width. The device is noninvasive, and it...

2012-04-01

186

21 CFR 870.3640 - Indirect pacemaker generator function analyzer.  

Code of Federal Regulations, 2010 CFR

...function analyzer is an electrically powered device that is used to determine pacemaker function or pacemaker battery function by periodically monitoring an implanted pacemaker's pulse rate and pulse width. The device is noninvasive, and it...

2010-04-01

187

21 CFR 870.3640 - Indirect pacemaker generator function analyzer.  

Code of Federal Regulations, 2010 CFR

...function analyzer is an electrically powered device that is used to determine pacemaker function or pacemaker battery function by periodically monitoring an implanted pacemaker's pulse rate and pulse width. The device is noninvasive, and it...

2011-04-01

188

21 CFR 870.3710 - Pacemaker repair or replacement material.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Pacemaker repair or replacement material. ...Prosthetic Devices § 870.3710 Pacemaker repair or replacement material. (a) Identification. A pacemaker repair or replacement material...

2009-04-01

189

21 CFR 870.3710 - Pacemaker repair or replacement material.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Pacemaker repair or replacement material. ...Prosthetic Devices § 870.3710 Pacemaker repair or replacement material. (a) Identification. A pacemaker repair or replacement material...

2010-04-01

190

21 CFR 870.3620 - Pacemaker lead adaptor.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Pacemaker lead adaptor. 870.3620 Section 870...Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device used to...

2009-04-01

191

21 CFR 870.3730 - Pacemaker service tools.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Pacemaker service tools. 870.3730 Section...Cardiovascular Prosthetic Devices § 870.3730 Pacemaker service tools. (a) Identification. Pacemaker service tools are devices such as...

2009-04-01

192

21 CFR 870.3620 - Pacemaker lead adaptor.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Pacemaker lead adaptor. 870.3620 Section 870...Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device used to...

2010-04-01

193

21 CFR 870.3730 - Pacemaker service tools.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Pacemaker service tools. 870.3730 Section...Cardiovascular Prosthetic Devices § 870.3730 Pacemaker service tools. (a) Identification. Pacemaker service tools are devices such as...

2010-04-01

194

21 CFR 870.3640 - Indirect pacemaker generator function analyzer.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Indirect pacemaker generator function analyzer. 870...Devices § 870.3640 Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker generator function analyzer is...

2009-04-01

195

21 CFR 870.3690 - Pacemaker test magnet.  

Code of Federal Regulations, 2010 CFR

... 2009-04-01 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...

2009-04-01

196

21 CFR 870.3690 - Pacemaker test magnet.  

Code of Federal Regulations, 2010 CFR

... 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...

2010-04-01

197

Lithium-iodine pacemaker cell  

SciTech Connect

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

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

1980-01-01

198

Calcium Transient and Sodium-Calcium Exchange Current in Human versus Rabbit Sinoatrial Node Pacemaker Cells  

PubMed Central

There is an ongoing debate on the mechanism underlying the pacemaker activity of sinoatrial node (SAN) cells, focusing on the relative importance of the “membrane clock” and the “Ca2+ clock” in the generation of the small net membrane current that depolarizes the cell towards the action potential threshold. Specifically, the debate centers around the question whether the membrane clock-driven hyperpolarization-activated current, I f, which is also known as the “funny current” or “pacemaker current,” or the Ca2+ clock-driven sodium-calcium exchange current, I NaCa, is the main contributor to diastolic depolarization. In our contribution to this journal's “Special Issue on Cardiac Electrophysiology,” we present a numerical reconstruction of I f and I NaCa in isolated rabbit and human SAN pacemaker cells based on experimental data on action potentials, I f, and intracellular calcium concentration ([Ca2+]i) that we have acquired from these cells. The human SAN pacemaker cells have a smaller I f, a weaker [Ca2+]i transient, and a smaller I NaCa than the rabbit cells. However, when compared to the diastolic net membrane current, I NaCa is of similar size in human and rabbit SAN pacemaker cells, whereas I f is smaller in human than in rabbit cells.

Verkerk, Arie O.

2013-01-01

199

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

PubMed

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

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

2013-01-01

200

[ESC Guidelines on Pacemaker Therapy 2013: what is new and relevant for daily practice?].  

PubMed

The European Society of Cardiology (ESC) and the European Heart Rhythm Association (EHRA) published new guidelines for pacemaker and cardiac resynchronisation therapy in June 2013. The most important recommendations for daily clinical practice of pacemaker therapy firstly refer to the diagnosis of bradycardia and bradycardia-symptom-correlation. Bradycardia is classified into persistent and intermittent, the latter with and without documentation of spontaneous bradycardia. Evidence for pacemaker therapy depends on the quality of bradycardia-symptom-correlation. The indication for pacing in sick-sinus-syndrome and AV block is significantly simplified and the use of implantable loop-recording in syncope of unknown origin encouraged. If loop recorders document long asymptomatic pauses, the authors felt that an indication for pacing exists if pauses exceed 6 sec. Other newly defined pacing indications are syncope in bundle branch block and very long PR (> 300 ms), particularly in older patients and those with structural heart disease. New insights and recommendations are further provided for complications of pacemaker therapy, right ventricular pacing sites, perioperative anticoagulation, pacing and magnetic resonance imaging and remote monitoring. In conclusion, the new ESC guidelines elegantly summarize results of new trials and studies in bradycardia and pacemaker therapy and provide valuable recommendations for daily practice. PMID:24046141

Israel, C W

2013-09-01

201

Technology Utilization Program Report.  

National Technical Information Service (NTIS)

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 part...

1974-01-01

202

Involvement of Autophagy in Cardiac Remodeling in Transgenic Mice with Cardiac Specific Over-Expression of Human Programmed Cell Death 5  

PubMed Central

Programmed cell death 5 (PDCD5) is a cytosolic protein suppressing growth of multiple types of cancer cells through activating p53. We hypothesized that PDCD5 plays an essential role in cardiac remodeling and function. PDCD5 was significantly up-regulated in the hearts from mice subjected to angiotensin II treatment or transverse aortic constriction. Thus, we generated transgenic mice over-expressing human PDCD5 under the control of alpha myosin heavy chain promoter to examine the role of PDCD5 in cardiac remodeling. Transgenic founder died spontaneously displayed enlarged heart. The high PDCD5 over-expressing line (10-fold) showed reduced survival rate, increase in heart weight normalized to body weight. Real-Time RT-PCR analysis revealed fetal gene program was up-regulated. Echocardiography and histopathological examination showed characteristics of dilated cardiomyopathy and heart failure in transgenic mice. Western blot and immunohistochemistry analysis showed autophagy was dramatically increased in transgenic mice as compared to WT littermates control mice, while apoptosis remained unchanged. The enhanced autophagy in high over-expressing line was associated with significant increase in p53 activity and its downstream target damage-regulated autophagy modulator expression. The low over-expressing line (3.5-fold) appeared normal, but was more susceptible to angiotensin II-induced cardiac hypertrophy. This study is the first providing evidence that PDCD5 plays an important role in cardiac remodeling.

An, Lin; Zhao, Xiwen; Wu, Jian; Jia, Jianguo; Zou, Yunzeng; Guo, Xizhi; He, Lin; Zhu, Hongxin

2012-01-01

203

Utility of the NavX(R) Electroanatomic Mapping System for Permanent Pacemaker Implantation in a Pregnant Patient with Chagas Disease  

PubMed Central

Chagas disease is a highly prevalent zoonosis in Mexico, Central, and South America. Early cardiac involvement is one of the most serious complications of this disease, and conduction disturbances may occur at an early age. We describe a young pregnant woman with Chagas disease and a high degree atrioventricular block, who required implantation of a permanent dual chamber pacemaker. Using an electroanatomic navigation EnSite NavX® system the pacemaker was successfully implanted with minimal fluoroscopic exposure. This case demonstrates the safety and feasibility of using an electroanatomic navigation system to guide permanent pacemaker implantation minimizing x-ray exposure in pregnant patients.

Velasco, Alejandro; Velasco, Victor Manuel; Rosas, Fernando; Cevik, Cihan; Morillo, Carlos A

2013-01-01

204

Electrophysiological and haemodynamic basis for application of new pacemaker technology in sick sinus syndrome and atrioventricular block  

Microsoft Academic Search

A fundamental description of pacemaker systems which are commercially available or in clinical validation is given as a background for their application in a series of 62 consecutive patients presenting over a period of 1 year for permanent cardiac pacing. The patients (23 (37%) sick sinus syndrome, 38 (61%) atrioventricular block, and 1 ventricular tachycardia) were studied electrophysiologically and haemodynamically

R Sutton; P Citron

1979-01-01

205

Mangalith: a new lithium pacemaker battery  

Microsoft Academic Search

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

G. Gerbier; G. Lehmann

1980-01-01

206

Design Overview Of Processor Based Implantable Pacemaker  

Microsoft Academic Search

Implantable pacemaker is a battery operated real time embedded system, which includes software\\/hardware codesign strategy. As it is placed within the heart by surgery, battery life is an important constraint to extend device lifetime. In this paper, pacemaker's functionalities like basic pacing, pulse width, refractory period in VOO mode has been realized using ultralow power processor MSP 430F1611 and IAR

Santosh D. Chede; Kishore D. Kulat

2008-01-01

207

Prediction of battery depletion in implanted pacemakers  

Microsoft Academic Search

By the use of a measuring oscilloscope and the standard electrocardiogram limb leads the degree of battery depletion in an implanted pacemaker can be estimated. A formula based on readings obtained by this means has been used to determine when Devices fixed rate pacemakers should be removed. Laboratory tests show that 90% of their useful life is obtained by this

Geoffrey Davies; Harold Siddons

1973-01-01

208

Involvement of Autophagy in Cardiac Remodeling in Transgenic Mice with Cardiac Specific Over-Expression of Human Programmed Cell Death 5  

Microsoft Academic Search

Programmed cell death 5 (PDCD5) is a cytosolic protein suppressing growth of multiple types of cancer cells through activating p53. We hypothesized that PDCD5 plays an essential role in cardiac remodeling and function. PDCD5 was significantly up-regulated in the hearts from mice subjected to angiotensin II treatment or transverse aortic constriction. Thus, we generated transgenic mice over-expressing human PDCD5 under

Lin An; Xiwen Zhao; Jian Wu; Jianguo Jia; Yunzeng Zou; Xizhi Guo; Lin He; Hongxin Zhu

2012-01-01

209

[Mutations in the heart's pacemaker channels--a new cause of sick sinus node syndrome and long-QT syndrome].  

PubMed

The sinus node hyperpolarization-activated If current generated by the cardiac pacemaker channels HCN2 and HCN4 determines the autonomous beating of the heart. Cardiac arrhythmias, like long-QT syndrome, are often caused by irregularities of the heart action potential generated by mutations in cardiac ion channel genes. Mutations in the HCN4 gene have been associated with sick sinus syndrome and long-QT syndrome. The identification of cardiac arrhythmia disease-associated genes makes possible new therapeutic strategies based on gene-specific drug treatment and gene therapy. PMID:18397618

Vitved, Tine; Lianee, Henriette Theilmann; Støvring, Birgitte; Sigurd, Bjarne M; Christiansen, Michael

2008-03-10

210

Uptake of a technology-assisted home-care cardiac rehabilitation program.  

PubMed

The prevalence of cardiovascular disease, a major cause of disease burden in Australia and other developed countries, is increasing due to a rapidly ageing population and environmental, biomedical and modifiable lifestyle factors. Although cardiac rehabilitation (CR) programs have been shown to be beneficial and effective, rates of referral, uptake and utilisation of traditional hospital or community centre programs are poor. Home-based CR programs have been shown to be as effective as centre-based programs, and recent advances in information and communication technologies (ICT) can be used to enhance the delivery of such programs. The Care Assessment Platform (CAP) is an integrated home-based CR model incorporating ICT (including a mobile phone and the internet) and providing all the core components of traditional CR (education, physical activity, exercise training, behaviour modification strategies and psychological counselling). The mobile phone given to patients has an integrated accelerometer and diary application for recording exercise and health information. A central database, with access to these data, allows mentors to assess patients' progress, assist in setting goals, revise targets and give weekly personal feedback. Mentors find the mobile-phone modalities practical and easy to use, and preliminary results show high usage rates and acceptance of ICT by participants. The provision of ICT-supported home-based CR programs may enable more patients in both metropolitan and remote settings to benefit from CR. PMID:21401482

Varnfield, Marlien; Karunanithi, Mohanraj K; Särelä, Antti; Garcia, Elsa; Fairfull, Anita; Oldenburg, Brian F; Walters, Darren L

2011-02-21

211

An Injury-Responsive Gata4 Program Shapes the Zebrafish Cardiac Ventricle  

PubMed Central

Summary A common principle of tissue regeneration is the reactivation of previously employed developmental programs [1–3]. During zebrafish heart regeneration, cardiomyocytes in the cortical layer of the ventricle induce the transcription factor gene gata4 and proliferate to restore lost muscle [4–6]. A dynamic cellular mechanism initially creates this cortical muscle in juvenile zebrafish, where a small number of internal cardiomyocytes breach the ventricular wall and expand upon its surface [7]. Here, we find that emergent juvenile cortical cardiomyocytes induce expression of gata4 similarly as during regeneration. Clonal analysis indicates that these cardiomyocytes make biased contributions to build the ventricular wall, whereas gata4+ cardiomyocytes have little or no proliferation hierarchy during regeneration. Experimental microinjuries or conditions of rapid organismal growth stimulate production of ectopic gata4+ cortical muscle, implicating biomechanical stress in morphogenesis of this tissue and revealing clonal plasticity. Induced transgenic inhibition defined an essential role for Gata4 activity in morphogenesis of the cortical layer and the preservation of normal cardiac function in growing juveniles, and again in adults during heart regeneration. Our experiments uncover an injury-responsive program that prevents heart failure in juveniles by fortifying the ventricular wall, one that is reiterated in adults to promote regeneration after cardiac damage.

Gupta, Vikas; Gemberling, Matthew; Karra, Ravi; Rosenfeld, Gabriel E.; Evans, Todd; Poss, Kenneth D.

2013-01-01

212

Pacemaker safety and long-distance running  

PubMed Central

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.

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

2004-01-01

213

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

PubMed

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

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

2014-03-01

214

Primary care provider perceptions of intake transition records and shared care with outpatient cardiac rehabilitation programs  

PubMed Central

Background While it is recommended that records are kept between primary care providers (PCPs) and specialists during patient transitions from hospital to community care, this communication is not currently standardized. We aimed to assess the transmission of cardiac rehabilitation (CR) program intake transition records to PCPs and to explore PCPs' needs in communication with CR programs and for intake transition record content. Method 144 PCPs of consenting enrollees from 8 regional and urban Ontario CR programs participated in this cross-sectional study. Intake transition records were tracked from the CR program to the PCP's office. Sixty-six PCPs participated in structured telephone interviews. Results Sixty-eight (47.6%) PCPs received a CR intake transition record. Fifty-eight (87.9%) PCPs desired intake transition records, with most wanting it transmitted via fax (n = 52, 78.8%). On a 5-point Likert scale, PCPs strongly agreed that the CR transition record met their needs for providing patient care (4.32 ± 0.61), with 48 (76.2%) reporting that it improved their management of patients' cardiac risk. PCPs rated the following elements as most important to include in an intake transition record: clinical status (4.67 ± 0.64), exercise test results (4.61 ± 0.52), and the proposed patient care plan (4.59 ± 0.71). Conclusions Less than half of intake transition records are reaching PCPs, revealing a large gap in continuity of patient care. PCP responses should be used to develop an evidence-based intake transition record, and procedures should be implemented to ensure high-quality transitional care.

2011-01-01

215

Atrio-ventricular block requiring pacemaker in patients with late onset Pompe disease.  

PubMed

Enzyme replacement therapy consistently improves cardiac function in infantile and juvenile onset patients with Pompe disease and cardiomyopathy, but is apparently not effective in preventing rhythm disorders, an emerging cardiac phenotype in long term survivors. In patients with late onset Pompe disease cardiomyopathy is an exceptional finding while heart rhythm disorders seem to be more frequent. We retrospectively identified, among a cohort of 131 French late onset Pompe disease patients, four patients with severe atrio-ventricular blocks requiring pacemaker implantation. These patients had no other risk factors for cardiovascular diseases or cardiomyopathy. In one patient the atrioventricular block was discovered while still asymptomatic. Cardiac conduction defects are relatively rare in late onset Pompe disease and may occur even in absence of cardiac symptoms or EKG abnormalities. However because of the possible life-threatening complications associated with these conduction defects, cardiac follow-up in patients with late onset Pompe disease should include periodical Holter-EKG monitoring. PMID:24844452

Sacconi, Sabrina; Wahbi, Karim; Theodore, Guillaume; Garcia, Jérémy; Salviati, Leonardo; Bouhour, Françoise; Vial, Christophe; Duboc, Denis; Laforêt, Pascal; Desnuelle, Claude

2014-07-01

216

Cardiac sarcoidosis: a comprehensive review  

PubMed Central

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.

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

2011-01-01

217

Novel effects of chromosome Y on cardiac regulation, chromatin remodeling, and neonatal programming in male mice.  

PubMed

Little is known about the functions of chromosome Y (chrY) genes beyond their effects on sex and reproduction. In hearts, postpubertal testosterone affects the size of cells and the expression of genes differently in male C57BL/6J than in their C57.Y(A) counterparts, where the original chrY has been substituted with that from A/J mice. We further compared the 2 strains to better understand how chrY polymorphisms may affect cardiac properties, the latter being sexually dimorphic but unrelated to sex and reproduction. Genomic regions showing occupancy with androgen receptors (ARs) were identified in adult male hearts from both strains by chromatin immunoprecipitation. AR chromatin immunoprecipitation peaks (showing significant enrichment for consensus AR binding sites) were mostly strain specific. Measurements of anogenital distances in male pups showed that the biologic effects of perinatal androgens were greater in C57BL/6J than in C57.Y(A). Although perinatal endocrine manipulations showed that these differences contributed to the strain-specific differences in the response of adult cardiac cells to testosterone, the amounts of androgens produced by fetal testes were not different in each strain. Nonetheless, chrY polymorphisms associated in newborn pups' hearts with strain-specific differences in genomic regions showing either AR occupancy, accessible chromatin sites, or trimethylation of histone H3 Lysine 4 marks, as well as with differential expression of 2 chrY-encoded histone demethylases. In conclusion, the effects of chrY on adult cardiac phenotypes appeared to result from an interaction of this chromosome with the organizational programming effects exerted by the neonatal testosterone surge and show several characteristics of being mediated by an epigenetic remodeling of chromatin. PMID:24105479

Praktiknjo, Samantha D; Llamas, Bastien; Scott-Boyer, Marie-Pier; Picard, Sylvie; Robert, François; Langlais, David; Haibe-Kains, Benjamin; Faubert, Denis; Silversides, David W; Deschepper, Christian F

2013-12-01

218

Universal Pacemaker of Genome Evolution  

PubMed Central

A fundamental observation of comparative genomics is that the distribution of evolution rates across the complete sets of orthologous genes in pairs of related genomes remains virtually unchanged throughout the evolution of life, from bacteria to mammals. The most straightforward explanation for the conservation of this distribution appears to be that the relative evolution rates of all genes remain nearly constant, or in other words, that evolutionary rates of different genes are strongly correlated within each evolving genome. This correlation could be explained by a model that we denoted Universal PaceMaker (UPM) of genome evolution. The UPM model posits that the rate of evolution changes synchronously across genome-wide sets of genes in all evolving lineages. Alternatively, however, the correlation between the evolutionary rates of genes could be a simple consequence of molecular clock (MC). We sought to differentiate between the MC and UPM models by fitting thousands of phylogenetic trees for bacterial and archaeal genes to supertrees that reflect the dominant trend of vertical descent in the evolution of archaea and bacteria and that were constrained according to the two models. The goodness of fit for the UPM model was better than the fit for the MC model, with overwhelming statistical significance, although similarly to the MC, the UPM is strongly overdispersed. Thus, the results of this analysis reveal a universal, genome-wide pacemaker of evolution that could have been in operation throughout the history of life.

Snir, Sagi; Wolf, Yuri I.; Koonin, Eugene V.

2012-01-01

219

Pacemakers charging using body energy  

PubMed Central

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.

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

2010-01-01

220

Pacemakers charging using body energy.  

PubMed

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

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

2010-01-01

221

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

PubMed

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

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

2010-09-15

222

Cardiac Rehabilitation  

MedlinePLUS

Cardiac rehabilitation (rehab) is a medically supervised program to help people who have A heart attack Angioplasty or coronary artery bypass grafting for coronary heart disease A heart valve repair or replacement A ...

223

Criteria for pacemaker explant in patients without a precise indication for pacemaker implantation.  

PubMed

Unnecessary pacemaker implantation may cause significant social and psychological consequences, the inconvenience of periodic office visits, and the expense of pulse generator replacement. Establishing adequate criteria for explantingpacemakers is crucial and has notyet been described. This study presents the results of a study protocol for explanting the pacemaker in patients without a clear indication for pacemaker implantation. Seventy pacemaker users without a clear reason for the implantation were included in the study conducted from August 1986 to November 1998 and were prospectively followed. The investigation consisted of clinical and neurological evaluations, echocardiogram, exercise testing, and tilt table testing. When these tests were negative, the pulse generator energy and stimulation rates were reprogrammed to the lowest values. Periodic Holter monitoring was conducted during follow-up. When asymptomatic for 1 year, patients underwent an electrophysiological evaluation of sinus and atrioventricular junction function and ventricular vulnerability. When the electrophysiological study was negative, pacemaker explantation was performed. Of the 70 patients, 35 had their pacemaker explanted; 3 were excluded due to a positive tilt table test and electrophysiological study, and 3 are waitingfor pacemaker explantation. Mean follow-up after pacemaker explantation was 30.3 months, and all patients remained asymptomatic, exceptfor one patient who died of a noncardiac cause. Critical analysis of pacemaker users without a well-established indication is justified because it may allowpacemaker explant in a significant proportion of these patients, and it may bring considerable social, economic, and psychological benefits. PMID:11990655

Martinelli, Martino; Costa, Roberto; Nishioka, Silvana; Pedrosa, Anísio; Siqueira, Sérgio; Crevelari, Elizabeth; Scanavacca, Maurício; d'Avila, André; Sosa, Eduardo

2002-03-01

224

Funny channels in the control of cardiac rhythm and mode of action of selective blockers  

Microsoft Academic Search

“Funny” (f) channels underlie the cardiac “pacemaker”If current, originally described as an inward current activated on hyperpolarization to the diastolic range of voltages in sino-atrial node myocytes [Brown, HF, DiFrancesco, D, Noble, SJ. How does adrenaline accelerate the heart? Nature 1979;280:235–236]. The involvement of funny channels in the generation and modulation of cardiac pacemaker activity has been amply demonstrated by

Dario DiFrancesco

2006-01-01

225

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 (...

226

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

PubMed Central

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 (ms2) (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.

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

2013-01-01

227

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

PubMed Central

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

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

2013-01-01

228

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

PubMed

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

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

2013-08-01

229

A recommended protocol for pacemaker follow-up: analysis of 1,705 implanted pacemakers.  

PubMed

This study, developed for the purpose of establishing an appropriate protocol for general follow-up of the paced patient, is based on clinical experience with patients derived from diverse specialties, geographical locations and protocol preferences. The analysis represents a four-year study of the transtelephonic follow-up of 1,705 implanted cardiac pacers, which represents 44,616 pacer-months of experience. There were 340 system malfunctions, 41% (141) due to battery exhaustion and 59% (199) due to other causes. Of all observed system failures 9.7% (33) occurred within 1 month of implantation, with the rate declining sharply thereafter until battery failures began to occur at approximately the twenty-fourth month. Only 10.9% (37) of all system failures were accompanied by clinical symptoms. Of the clinical failures, 62% (23) occurred in patients who were tested at intervals greater than 10 weeks. Our analysis indicates that testing should be performed weekly for the first month following lead manipulation. Thereafter, tests should be performed at 8- to 10-week intervals for the first 24 months of pacemaker life. During the third postimplant year tests should be conducted more frequently, depending on the energy source of the generator. PMID:879885

Mantini, E L; Majors, R K; Kennedy, J R; Lebo, G R

1977-07-01

230

Development and pilot test of a peer-support based Cardiac-Diabetes Self-Management Program: A study protocol  

PubMed Central

Background People with cardiac disease and type 2 diabetes have higher hospital readmission rates (22%) compared to those without diabetes (6%). Self-management is an effective approach to achieve better health outcomes; however there is a lack of specifically designed programs for patients with these dual conditions. This project aims to extend the development and pilot test of a Cardiac-Diabetes Self-Management Program incorporating user-friendly technologies and the preparation of lay personnel to provide follow-up support. Methods/Design A randomised controlled trial will be used to explore the feasibility and acceptability of the Cardiac-Diabetes Self-Management Program incorporating DVD case studies and trained peers to provide follow-up support by telephone and text-messaging. A total of 30 cardiac patients with type 2 diabetes will be randomised, either to the usual care group, or to the intervention group. Participants in the intervention group will received the Cardiac-Diabetes Self-Management Program in addition to their usual care. The intervention consists of three face-to-face sessions as well as telephone and text-messaging follow up. The face-to-face sessions will be provided by a trained Research Nurse, commencing in the Coronary Care Unit, and continuing after discharge by trained peers. Peers will follow up patients for up to one month after discharge using text messages and telephone support. Data collection will be conducted at baseline (Time 1) and at one month (Time 2). The primary outcomes include self-efficacy, self-care behaviour and knowledge, measured by well established reliable tools. Discussion This paper presents the study protocol of a randomised controlled trial to pilot evaluates a Cardiac-Diabetes Self-Management program, and the feasibility of incorporating peers in the follow-ups. Results of this study will provide directions for using such mode in delivering a self-management program for patients with both cardiac condition and diabetes. Furthermore, it will provide valuable information of refinement of the intervention program. Trial Registration Number ACTRN12611000086965

2011-01-01

231

Biventricular Pacemaker Implantation via the Femoral Vein  

PubMed Central

We report the case of biventricular pacemaker implantation via the femoral vein, in a patient with impossibility of using standard superior vein approach and a contraindication to epicardial lead placement.

Agosti, Sergio; Brunelli, Claudio; Bertero, Giovanni

2012-01-01

232

21 CFR 870.3670 - Pacemaker charger.  

Code of Federal Regulations, 2013 CFR

21 Food and Drugs 8 2013-04-01 2013-04-01... 870.3670 Section 870.3670 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT...used transcutaneously to recharge the batteries of a rechargeable pacemaker....

2013-04-01

233

Sick Sinus Syndrome Due to Cardiac Amyloidosis  

Microsoft Academic Search

In a patient suffering from cardiac amyloidosis a case of sick sinus syndrome, manifested by markedly prolonged recovery time of the sinus node, was documented by an atrial pacing study. The first A-V junctional escape interval was markedly prolonged following the termination of the atrial pacing, pointing to a coexisting A-V nodal dysfunction. The patient required a permanent artificial pacemaker

Lewis W. Gray; Peter R. Duca; Edward K. Chung

1978-01-01

234

Normal heart rhythm is initiated and regulated by an intracellular Calcium clock within pacemaker cells  

PubMed Central

For almost half a century it has been thought that the heart rhythm originates on the surface membrane of the cardiac pacemaker cells and is driven by voltage-gated ion channels (membrane clocks). Data from several recent studies, however, conclusively show that the rhythm is initiated, sustained, and regulated by oscillatory Ca2+ releases (Ca2+ clock) from the sarcoplasmic reticulum, a major Ca2+ store within sinoatrial node cells, the primary heart’s pacemakers. Activation of the local oscillatory Ca2+ releases is independent of membrane depolarization and driven by a high level of basal state phosphorylation of Ca2+ cycling proteins. The releases produce Ca2+ wavelets under the cell surface membrane during the later phase of diastolic depolarization and activate the forward mode of Na+/Ca2+ exchanger resulting in inward membrane current, which ignites an action potential. Phosphorylation-dependent gradation of speed at which Ca2+ clock cycles is the essential regulatory mechanism of normal pacemaker rate and rhythm. The robust regulation of pacemaker function is insured by tight integration of Ca2+ and membrane clocks: the action potential shape and ion fluxes are tuned by membrane clocks to sustain operation of the Ca2+ clock which produces timely and powerful ignition of the membrane clocks to effect action potentials.

Maltsev, Victor A.; Lakatta, Edward G.

2007-01-01

235

Service Life of Domestic Implanted Pacemakers  

Microsoft Academic Search

The results obtained for a group of patients from the database of the Moscow Municipal Center for electrocar-dioctimulation\\u000a were processed. The dates of primary implantation and reimplantation of pacemakers were taken into account. A total of 330\\u000a pacemakers were replaced because of battery discharge. Mean, estimated, warranty, and gamma-percentage service life of two\\u000a domestic models and one foreign model of

I. A. Dubrovskii; E. V. Pervova

2009-01-01

236

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

PubMed Central

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

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

2014-01-01

237

Isolated Cardiac Involvement in Primary Amyloidosis  

PubMed Central

Cardiac amyloidosis is an infiltrative cardiomyopathy with a grave prognosis. Its clinical manifestations include restrictive cardiomyopathy, diastolic heart failure, conduction defects, and arrhythmias. Isolated cardiac involvement and significant conduction disturbances are reported very infrequently. We report a rare case of isolated cardiac involvement in primary amyloidosis, in a 76-year-old man who initially presented with sick sinus syndrome that necessitated permanent pacemaker insertion. Subsequent symptoms of heart failure led to additional evaluation, including an endomyocardial biopsy that revealed primary cardiac amyloidosis. Medical therapy improved the patient's symptoms, and he was discharged from the hospital in stable condition. In addition to discussing the patient's case, we review the relevant medical literature.

Pattanshetty, Deepak J.; Bhat, Pradeep K.; Chamberlain, Wendy A.; Lyons, Matthew R.

2013-01-01

238

Glossopharyngeal neuralgia associated with cardiac syncope.  

PubMed

Glossopharyngeal neuralgia is an uncommon condition that has rarely been described in association with syncope. We report here 2 cases of glossopharyngeal neuralgia in elderly patients. Both were male and underwent temporary pacemaker insertion to prevent syncopal episodes. We discuss the clinical and surgical treatment of glossopharyngeal neuralgia, the role of cardiac stimulation, and the possible physiopathological mechanism of the associated cardiac disturbances. PMID:12045849

Elias, Jorge; Kuniyoshi, Ricardo; Carloni, Wilson Valadão Hermes; Borges, Mauricio Rocha; Peixoto, Carlos Alberto; Pimentel, Derval

2002-05-01

239

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

PubMed Central

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.

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

2013-01-01

240

Sudden pain on pacemaker pocket followed by explosion in a patient with a permanent pacemaker.  

PubMed

An 81-year-old woman with a mercury-zinc powered permanent pacemaker experienced the sudden pain on her pacemaker pocket followed by an explosion. We are aware of no other report of the spontaneous and symptomatic bursting of a generator battery with fracture of the pulse generator capsule. PMID:3816328

Ruiz-Santana, S; Aguado-Bourrey, J M; Martin-Rodriguez, A; Perez-Arriaga, M

1987-03-01

241

Gender differences in risk factors of obese patients after cardiac rehabilitation program  

PubMed Central

Background: Obesity is common in patients with cardiovascular disease (CVD) and the vast majority of patients entering into cardiac rehabilitation program (CRP) are obese. Regarding the gender differences, the risk of developing coronary heart disease (CHD) is recognized to be different between obese men and women. So, the purpose of this study was to explore the effect of CRP in functional capacity (FC) and risk factors, such as obesity indexes, lipid profiles, and fasting blood sugar (FBS) in obese men and women with CHD. Marterials and Methods: In an observational study between 2000 and 2011, we evaluated a total of 156 obese men and women patients with CHD who were referred to cardiac rehabilitation of Isfahan Cardiovascular Research Institute. Before and after CRP, FC and risk factors were assessed and all the participants completed this period. Data were analyzed with SPSS software version 15. For comparing the mean of outcomes, independent t tests and paired sample t tests were used. Results: Data revealed, after CRP, obese women had significant improvement in most evaluated risk factors except total cholesterol (P = 0.05) and FBS (P = 0.09); and obese men had favorable changes in weight (P = 0.00) and body mass index (P = 0.00), FC (P = 0.00) and total cholesterol (P = 0.02); in spite of no significant differences in other lipid profiles. Comparing the 2 groups did not show any significant differences unless high-density lipoprotein cholesterol (P = 0.01) and low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio (P = 0.02) had greater improvement in obese women. Conclusion: We concluded that CRP is an important step initiating the process of risk reduction and restoration of FC in obese men and obese women with CHD under attendance and supervision of physician, nurse, and exercise physiologist.

Ghashghaei, Fatemeh Esteki; Sadeghi, Masoumeh; Rabiei, Katayoun; Roohafza, Hamidreza; Sarrafzadegan, Nizal

2012-01-01

242

Impact of increasing current drain in a pacemaker operating during activation of the elective replacement indicator.  

PubMed

The occurrence of a 13.8 s episode of ventricular asystole in a patient whose VVIR pacemaker displayed the elective replacement indicator (ERI) is reported. Increasing battery current drain by VARIO testing and programming of the emergency VVI mode markedly increased battery current drain with a resultant decrease in the battery voltage below the pacing threshold. The prolonged lack of capture occurred because the lowered battery voltage could not return instantaneously to its previous level after the demand for a higher battery current drain had ceased. Rather, the battery voltage increased progressively to its previous level and successful capture was eventually regained at the previous base rate. When a pacemaker is at or near the ERI point, it is important to avoid any manipulation (including VARIO testing) that increases battery current drain so as to prevent prolonged ventricular asystole in pacemaker-dependent patients. PMID:22105353

Stroobandt, R X; Barold, S S

2011-12-01

243

The effectiveness of rigid pericardial endoscopy for minimally invasive minor surgeries: cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation  

PubMed Central

Background The efficacy and safety of rigid pericardial endoscopy as the promising minimally invasive approach to the pericardial space was evaluated. Techniques for cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation were developed. Methods Two swine and 5 canines were studied to evaluate the safety and efficacy of rigid pericardial endoscopy. After a double pericardiocentesis, a transurethral rigid endoscope was inserted into the pericardial space. The technique to obtain a clear visual field was examined, and acute complications such as hemodynamic changes and the effects on intra-pericardial pressure were evaluated. Using custom-made needles, pacemaker leads, and forceps, the applications for cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation were also evaluated. Results The use of air, the detention of a stiff guide wire in the pericardial space, and the stretching of the pericardium with the rigid endoscope were all useful to obtain a clear visual field. A side-lying position also aided observation of the posterior side of the heart. As a cell transplantation methodology, we developed an ultrasonography-guided needle, which allows for the safe visualization of transplantation without major complications. Pacemaker leads were safely and properly implanted, which provides a better outcome for cardiac resynchronizing therapy. Furthermore, the success of clear visualization of the pulmonary veins enabled us to perform epicardial ablation. Conclusions Rigid pericardial endoscopy holds promise as a safe method for minimally invasive cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation by allowing clear visualization of the pericardial space.

2012-01-01

244

Evaluation of the extended Holter capabilities of the Prometheus implantable research pacemaker  

Microsoft Academic Search

An arrhythmia detection program for the implantable Medtronic Prometheus research pacemaker was evaluated by making it analyze interval sequences from Holter tapes already evaluated by the ATREC Holter analysis system. Eight 10-minute periods from 24-hour Holter tapes from 4 patients were selected, as they presented ventricular arrhythmias ranging from extrasystoles to sustained tachycardia. Twenty-nine tests were performed with various combinations

R. Hunen; P. Maison-Blanche; A. Guezennec; R. Urban; N. Bakels; I. Bourgeois; P. Coumel

1990-01-01

245

[Undetermined type of acute coronary syndrome in a patient with a pacemaker].  

PubMed

Venticular paced rhythm makes diagnosis of acute myocardial infarction difficult. We present a case of a 77-year-old woman with cardiac DDD pacemaker, suffering from diabetes, arterial hypertension and renal insufficiency. She was admitted to hospital due to heavy chest pain, radiated to neck and jaw and shortness of breath. The electrocardiogram recorded on admission showed ventricular paced rhythm and ST segment elevation > 0.5 mV, which fulfilled Sgarbossa's criteria for indetermined acute coronary syndrome in a patient with pacemaker. Troponin levels were not increased. Severe stenosis of left anterior descendent coronary artery was revealed in coronarography and percutaneus coronary angioplasty with stent implantation was performed immediately. PMID:19521944

Wozakowska-Kap?on, Beata; Weso?owska, Kamilla; Bakowski, Dawid; Bartkowiak, Rados?aw

2009-05-01

246

Synchronization of Coupled Neurons Controlled by a Pacemaker  

NASA Astrophysics Data System (ADS)

We investigate synchronization of Hindmarsh—Rose neurons with gap junctions under the control of a pacemaker. In a ring Hindmarsh—Rose neuronal network, the coupled neurons with the pacemaker can occur in synchronization more easily than those without the pacemaker. Furthermore, the pacemaker can induce phase synchronization or nearly-complete synchronization of nonidentical neurons. This synchronization can occur more easily when time delay is considered. Theses results can be helpful to understand the activities of the real neuronal system.

Li, Mei-Sheng; Zhang, Hong-Hui; Zhao, Yong; Shi, Xia

2011-01-01

247

Pacemaker leads: performance and progress.  

PubMed

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

de Voogt, W G

1999-03-11

248

Antibiotic prophylaxis in permanent pacemaker implantation: a prospective randomised trial  

Microsoft Academic Search

BACKGROUND--Pacemaker pocket infection is a potentially serious problem after permanent pacemaker implantation. Antibiotic prophylaxis is commonly prescribed to reduce the incidence of this complication, but current trial evidence of its efficacy is conflicting. A large prospective randomised trial was therefore performed of antibiotic prophylaxis in permanent pacemaker implantation. The intention was firstly to determine whether antibiotic prophylaxis is efficacious in

J P Mounsey; M J Griffith; M Tynan; F K Gould; A F MacDermott; R G Gold; R S Bexton

1994-01-01

249

Endothelial and cardiac progenitors: boosting, conditioning and (re)programming for cardiovascular repair.  

PubMed

Preclinical studies performed in cell culture and animal systems have shown the outstanding ability of stem cells to repair ischemic heart and lower limbs by promoting the formation of new blood vessels and new myocytes. In contrast, clinical studies of stem cell administration in patients with myocardial ischemia have revealed only modest, although promising, results. Basic investigations have shown the feasibility of adult cells reprogramming into pluripotent cells by defined factors, thus opening the way to the devise of protocols to ex vivo derive virtually unexhausted cellular pools. In contrast, cellular and molecular studies have indicated that risk factors limit adult-derived stem cell survival, proliferation and engraftment in ischemic tissues. The use of fully reprogrammed cells raises safety concerns; therefore, adult cells remain a primary option for clinicians interested in therapeutic cardiovascular repair. Pharmacologic approaches have been devised to restore the cardiovascular repair ability of failing progenitors from patients at risk. In the present contribution, the most advanced pharmacologic approaches to (re)program, boost, and condition endothelial and cardiac progenitor cells to enhance cardiovascular regeneration are discussed. PMID:21035506

Pesce, Maurizio; Burba, Ilaria; Gambini, Elisa; Prandi, Francesca; Pompilio, Giulio; Capogrossi, Maurizio C

2011-01-01

250

The utilization of radionuclide myocardial perfusion imaging and cardiac catheterization under Taiwan's universal health insurance program.  

PubMed

This study examines the utilization patterns of myocardial perfusion imaging (MPI) and cardiac catheterization (CC) under Taiwan's national health insurance program. This study used the longitudinal health insurance database with 1,000,000 people were randomly selected from the national health insurance research database. This study obtained data from these patients with coronary artery disease (CAD) and comparison with the utilization of MPI or CC between 2005 and 2009. The incidence of CAD did not significantly change, while the prevalence of CAD, utilization of MPI, and the utilization of CC for the CAD patients increased annually. There were the most CAD patients in Northern Taiwan (43.5%), followed by Southern, Central, and Eastern Taiwan. The utilizations of both of MPI (12.7 per 100 CAD patients) and CC (10.6 per 100 CAD patients) were most frequent in Northern Taiwan followed by Southern, Central, and Eastern Taiwan. However, the MPI/CC ratio was 1.20 in Northern Taiwan, followed by Southern, Central, and Eastern Taiwan (0.88, 0.64, and 0.52, respectively, P = 0.0008). The use of MPI was higher than CC only in Northern Taiwan. MPI may be underutilized to serve the role of gatekeeper for CC in the other regions. PMID:23515948

Lin, Ming-Chia; Yen, Ruoh-Fang; Chen, Huei-Yung; Muo, Chih-Hsin; Wang, Hsin-Ell; Chen, Chuan-Lin; Kao, Chia-Hung

2013-06-01

251

Cardiac output in single-lead VDD pacing versus rate-matched VVIR pacing.  

PubMed

The importance of atrioventricular synchronous pacing compared with single-chamber rate-responsive pacing is still under discussion, especially for low-intensity workload representing daily life activities. We evaluated hemodynamics in single-lead VDD pacing versus VVIR pacing in 11 patients (8 men and 3 women, aged 58.6 +/- 13.8 years) with normal left ventricular function and a previously implanted single-lead VDDR pacemaker. A low-intensity steady-state treadmill test at 1 to 2.5 mph with a gradient of 2% to 4% was performed. Cardiac output was determined using a standard carbon dioxide rebreathing technique. Initially, the VDD mode was programmed, and after 5 minutes of exercise, cardiac output was measured in steady-state conditions. The pacemaker was then reprogrammed to the VVI mode at a rate 5 to 10 beats above the maximal atrial tracking rate to simulate rate-matched VVIR pacing (VVIRm). After 5 additional minutes of steady-state exercise, cardiac output was measured again. The maximal atrial rate in the VDD mode was 119 +/- 19 beats/min versus a programmed rate of 129 +/- 18 beats/min in the VVIRm mode. VDD pacing resulted in a significantly higher cardiac output than VVIRm pacing (10.6 +/- 1.9 vs 9.2 +/- 1.4 L/min; p < 0.002), with a mean difference of 1.6 +/- 1.2 L/min between the 2 modes. In the VDD mode, stroke volume (90.7 +/- 20.1 vs 71.6 +/- 13.0 ml; p < 0.001) and maximal oxygen uptake (1,183 +/- 264 vs 1,076 +/- 289 ml/min, p < 0.01) were also higher than in VVIRm.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7732998

Nowak, B; Voigtländer, T; Himmrich, E; Liebrich, A; Poschmann, G; Epperlein, S; Treese, N; Meyer, J

1995-05-01

252

Physiologic control of cardiac assist devices.  

PubMed

Total artificial hearts (TAHs) and biventricular assist devices (BVADs) have varying levels of acceptance and reliability, and the research on both focuses on their control mechanisms. Efforts generally aim to achieve a response to physiologic demand and left/right output balance, and beneficial cardiac output (CO) and effective control mechanisms have been achieved by eliciting a Starting-like response to preload and afterload. Such control mechanisms, however, generally base device output on a single parameter, such as the preload on the heart. Current TAHs and BVADs provide relatively fixed oxygen delivery to patients with large physiologically induced variations in oxygen consumption. This paper aims to document fluctuations in oxygen consumption that are normal in BVAD and TAH patients, identify a number of patient-generated signals that reflect these fluctuations, and describe a multitiered control algorithm based upon these signals. Such a control system may offer better response times and more physiologic cardiac outputs. There currently exists a microprocessor-based control mechanism that can be adapted to control TAHs and BVADs using input from a variety of sensors, and it can be found in modern implantable pulse generators (IPGs). Today's pacemakers are capable of rate control and can run diagnostic programs and store data that could be valuable in the evaluation of the patient's condition. PMID:8694700

Hall, A W; Soykan, O; Harken, A H

1996-03-01

253

PATIENT COMPREHENSION OF AN INTERACTIVE, COMPUTER-BASED INFORMATION PROGRAM FOR CARDIAC CATHETERIZATION: A COMPARISON WITH STANDARD INFORMATION  

PubMed Central

Background Several studies suggest that standard verbal and written consent information for treatment is often poorly understood by patients and their families. This study examined the effect of an interactive computer-based information program on patients’ understanding of cardiac catheterization. Methods 135 adult patients scheduled to undergo diagnostic cardiac catheterization were randomized to receive details about the procedure using either standard institutional verbal and written information (SI), or interactive computerized information (ICI) preloaded on a laptop computer. Understanding was measured using semi-structured interviews at baseline (i.e, before information was given), immediately following cardiac catheterization (Early understanding), and two weeks post-procedure (Late understanding). The primary study outcome was the change from baseline to Early understanding between groups. Results Subjects randomized to the ICI intervention had significantly greater improvement in understanding compared to those who received the SI (net change 0.81; 95% confidence interval: 0.01, 1.6). Significantly more subjects in the ICI group had complete understanding of the risks of cardiac catheterization (53.6% vs 23.1%, P< 0.05) and options for treatment (63.2% vs 46.2%, P< 0.05) compared to the SI group, respectively. Several predictors of improved understanding were identified including baseline knowledge (P< 0.001), younger age (P = 0.002), and use of the ICI (p = 0.003). Conclusions Results suggest that an interactive computer-based information program for cardiac catheterization may be more effective in improving patient understanding than conventional written consent information. This technology, therefore, holds promise as a means of presenting understandable detailed information regarding a variety of medical treatments and procedures.

Tait, Alan R.; Voepel-Lewis, Terri; Moscucci, Mauro; Brennan-Martinez, Colleen M.; Levine, Robert

2009-01-01

254

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

PubMed

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

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

1996-10-01

255

Twins with implanted pacemakers: Is there an increased mortality risk for the co-twin? A follow-up study based on the Danish Twin Registry and the Danish Pacemaker Register  

Microsoft Academic Search

BackgroundThe main indications for implanting a cardiac pacemaker are either acquired atrio-ventricular block (AVB) or sick sinus syndrome (SSS). In general, the exact aetiology of these conditions is unknown. Genetic factors may play a role. Untreated AVB is associated with increased mortality but SSS seems to have a good prognosis.The present study was designed to assess whether first-degree relatives of

Claus Tveskov; Axel Skytthe; Per Arnsbo; James W. Vaupel; Mogens Møller; Kaare Christensen

2005-01-01

256

Predictive factors for pacemaker requirement after transcatheter aortic valve implantation  

PubMed Central

Background Transcatheter aortic valve implantation (TAVI) has been established as a treatment option for inoperable patients with symptomatic aortic valve stenosis. However, patients suffer frequently from conduction disturbances after TAVI. Methods Baseline, procedural as well as surface and intracardiac ECG parameters were evaluated for patients treated with TAVI and a comparison between patients requiring pacemaker with those not suffering from relevant conduction disorders were done. Results TAVI was successfully in all patients (n=45). Baseline surface and intracardiac ECG recording revealed longer PQ (197.1±51.2 msec versus 154.1±32.1 msec; p<0.001), longer AH (153.6±43.4 msec versus 116.1±31.2 msec; p<0.001) and HV interval (81.7±17.8 msec versus 56.8±8.5 msec; p<0.001) in patients with need for a pacemaker (n=23) versus control group (n=22); furthermore, 7-day follow-up analysis showed a higher prevalence of new left bundle branch block (LBBB) (87.0% versus 31.9%; p<0.001). Multivariate analysis revealed that only new LBBB, QRS duration >120 msec and a PQ interval >200 msec immediately (within 60 minutes) after implantation of the aortic valve were predictors for high-grade (type II second-degree and third-degree) AV block. Other clinical parameters as well as baseline electrocardiographic parameters had no impact on critical conduction delay. Conclusion Cardiac conduction disturbances are common after TAVI. The need for pacing after TAVI is predictable by surface ECG evaluation immediately (within 60 minutes) after the procedure.

2012-01-01

257

A novel program focused on women survivors who were enrolled in a cardiac arrest pathway.  

PubMed

The number of cases of out-of-hospital cardiac arrest is estimated to be 300,000/year in the United States. Two landmark studies published in 2002 demonstrated that therapeutic hypothermia decreased mortality and improved neurological outcome after out-of-hospital cardiac arrest. Our institutional pathway for the management of survivors of cardiac arrest stresses teamwork involving multiple disciplines, including cardiology, critical care, nursing, neurology, infectious diseases, physical therapy, social work, and pastoral care. Involvement of the patients' families is critical in the understanding of the process and in the decision making and goals of care when neurological prognosis is poor. In a unique approach, we have included the survivors in the process. Our approach to quality improvement includes a yearly conference incorporating the voices of survivors and families. This conference serves as a means to review our experience, educate clinicians, involve all healthcare providers in the outcome, and provide a model of communication and professionalism to trainees. During review of our experience, we noted the small number of women undergoing therapeutic hypothermia, accounting for only 21% of all patients undergoing this therapy after cardiac arrest. This led to a conference that focused on cardiac disease and cardiac arrest in women. PMID:23411605

Herzog, Eyal; Tamis, Jacqueline; Aziz, Emad F; Shapiro, Janet M

2013-03-01

258

Autonomic cardiac innervation  

PubMed Central

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

Hasan, Wohaib

2013-01-01

259

Intrapericardial pacemaker in a 2-kilogram newborn.  

PubMed

A 2-kilogram child had a pacemaker implanted by a subxyphoid approach with the generator located under the rectus sheath. Days later, the battery eroded the abdominal wall and the peritoneum. The whole system was removed and a new one was implanted inside the pericardium on an emergent basis. PMID:23066539

Gil-Jaurena, Juan-Miguel; Castillo, Rafael; Rubio, Lorena

2012-08-01

260

Pacemaker neurons within newborn spinal pain circuits  

PubMed Central

Spontaneous activity driven by “pacemaker” neurons, defined by their intrinsic ability to generate rhythmic burst-firing, contributes to the development of sensory circuits in many regions of the immature CNS. However, it is unknown if pacemaker-like neurons are present within central pain pathways in the neonate. Here we provide evidence that a subpopulation of glutamatergic interneurons within lamina I of the rat spinal cord exhibits oscillatory burst-firing during early life, which occurs independently of fast synaptic transmission. Pacemaker neurons were distinguished by a higher ratio of persistent, voltage-gated Na+ conductance to leak membrane conductance (gNa,P / gleak) compared to adjacent, non-bursting lamina I neurons. The activation of high-threshold (N-type and L-type) voltage-gated Ca2+ channels also facilitated rhythmic burst-firing by triggering intracellular Ca2+ signaling. Bursting neurons received direct projections from high-threshold sensory afferents, but transmitted nociceptive signals with poor fidelity while in the bursting mode. The observation that pacemaker neurons send axon collaterals throughout the neonatal spinal cord raises the possibility that intrinsic burst-firing could provide an endogenous drive to the developing sensorimotor networks which mediate spinal pain reflexes.

Li, Jie; Baccei, Mark L.

2011-01-01

261

[Electrophysiological and hemodynamic consequences of pacemaker syndrome].  

PubMed

The pacemaker syndrome is a complex of adverse clinical, hemodynamic and electrophysiologic signs temporally related to the onset of ventricular pacing and having no other causes. We observed 975 patients (454 men and 251 women, mean age 67.1+/-2.4 years) who received ventricular VVI pacemakers because of sick sinus syndrome or complete atrio-ventricular block. The presence of ventriculo-atrial conduction was confirmed by transesophageal ECG. Pacemaker syndrome was diagnosed in 121 patients (12.4%) who had the following complaints: general weakness (n=82), rapid fatigability (n=51), retarded thinking (n=43), dizziness (n=75), exertional dyspnea (n=86), anginal pain at rest (n=14), or exertion (n=43), unpleasant pulsation of neck vessels (n=41), transient hypotension (n=54), syncope (n=5). Retrograde P-wave was registered in standard ECG-leads in 98 (80.9%) and only on transesophageal ECG - in 23 patients (19%). Stroke volume after stopping of ventricular pacing (mean heart rate during sinus rhythm - 52.1+/-3/min) increased in 97 (80.2%) and decreased in 24 patients (19.8%). Main method of treatment of pacemaker syndrome was restoration of atrioventricular synchrony. PMID:16234792

Medziavichius, P A; Medziavichene, V; Zhaliunas, R

2005-01-01

262

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

Microsoft Academic Search

New multi-programmable pacemakers frequently employ complementary metal oxide semiconductors (CMOS). This circuitry appears more sensitive to the effects of ionizing radiation when compared to the semiconductor circuits used in older pacemakers. A case of radiation induced runaway pacemaker in a CMOS device is described. Because of this and other recent reports of radiation therapy-induced CMOS type pacemaker failure, these pacemakers

Alan A. Lewin; Christopher F. Serago; James G. Schwade; Andre A. Abitbol; Stephen C. Margolis

1984-01-01

263

Reversible, complete atrioventricular block caused by primary cardiac lymphoma in a nonimmunocompromised patient.  

PubMed

Primary cardiac lymphoma (PCL) is a rare entity that commonly presents as a heart rhythm disorder. We describe a previously healthy, immunocompetent patient presenting with complete atrioventricular block (AVB). The patient was found to have a cardiac mass on magnetic resonance imaging and underwent percutaneous biopsy eventually diagnosing PCL. After pacemaker implantation, the patient's tumor responded rapidly to chemotherapy and the AVB completely resolved. In otherwise healthy patients presenting with AV block, cardiac tumor should be considered. Additionally, if PCL is diagnosed and the patient is clinically stable with AVB, it may be reasonable to delay pacemaker implantation until the clinical response to chemotherapy is evaluated. PMID:22571682

Crisel, Ryan K; Knight, Bradley P; Kim, Susan S

2012-12-01

264

Measuring pacemaker dose: a clinical perspective.  

PubMed

Recently in our clinic, we have seen an increased number of patients presenting with pacemakers and defibrillators. Precautions are taken to develop a treatment plan that minimizes the dose to the pacemaker because of the adverse effects of radiation on the electronics. Here we analyze different dosimeters to determine which is the most accurate in measuring pacemaker or defibrillator dose while at the same time not requiring a significant investment in time to maintain an efficient workflow in the clinic. The dosimeters analyzed here were ion chambers, diodes, metal-oxide-semiconductor field effect transistor (MOSFETs), and optically stimulated luminescence (OSL) dosimeters. A simple phantom was used to quantify the angular and energy dependence of each dosimeter. Next, 8 patients plans were delivered to a Rando phantom with all the dosimeters located where the pacemaker would be, and the measurements were compared with the predicted dose. A cone beam computed tomography (CBCT) image was obtained to determine the dosimeter response in the kilovoltage energy range. In terms of the angular and energy dependence of the dosimeters, the ion chamber and diode were the most stable. For the clinical cases, all the dosimeters match relatively well with the predicted dose, although the ideal dosimeter to use is case dependent. The dosimeters, especially the MOSFETS, tend to be less accurate for the plans, with many lateral beams. Because of their efficiency, we recommend using a MOSFET or a diode to measure the dose. If a discrepancy is observed between the measured and expected dose (especially when the pacemaker to field edge is <10 cm), we recommend analyzing the treatment plan to see whether there are many lateral beams. Follow-up with another dosimeter rather than repeating multiple times with the same type of dosimeter. All dosimeters should be placed after the CBCT has been acquired. PMID:21875785

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

2012-01-01

265

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

PubMed Central

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

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

2013-01-01

266

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

PubMed

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

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

2011-01-01

267

Determination of 3D positions of pacemaker leads from biplane angiographic sequences.  

PubMed

In vitro and in vivo analyses of stress on pacemaker leads and their components during the heart cycle have become especially important because of incidences of failure of some of these mechanical components. For stress analyses, the three-dimensional (3D) position, shape, and motion of the pacemaker leads must be known accurately at each time point during the cardiac cycle. We have developed a method for determination of the in vivo 3D positions of pacemaker leads during the entire heart cycle. Sequences of biplane images of patients with pacemakers were obtained at 30 frames/s for each projection. The sequences usually included at least two heart cycles. After patient imaging, biplane images of a calibration object were obtained from which the biplane imaging geometry was determined. The centerlines of the leads and unique, identifiable points on the attached electrodes were indicated manually for all acquired images. Temporal interpolation of the lead and electrode data was performed so that the temporal nonsynchronicity of the image acquisition was overcome. Epipolar lines, generated from the calculated geometry, were employed to identify corresponding points along the leads in the pairs of biplane images for each time point. The 3D positions of the lead and electrodes were calculated from the known geometry and from the identified corresponding points in the images. Using multiple image sets obtained with the calibration object at various orientations, the precision of the calculated rotation matrix and of the translation vector defining the imaging geometry was found to be approximately 0.7 degree and 1%, respectively. The 3D positions were reproducible to within 2 mm, with the error lying primarily along the axis between the focal spot and the imaging plane. Using data obtained by temporally downsampling to 15 frames/s, the interpolated data were found to lie within approximately 2 mm of the true position for most of the heart cycle. These results indicate that, with this technique, one can reliably determine pacemaker lead positions throughout the heart cycle, and thereby it will provide the basis for stress analysis on pacemaker leads. PMID:9434968

Hoffmann, K R; Williams, B B; Esthappan, J; Chen, S Y; Carroll, J D; Harauchi, H; Doerr, V; Kay, G N; Eberhardt, A; Overland, M

1997-12-01

268

21 CFR 870.3680 - Cardiovascular permanent or temporary pacemaker electrode.  

Code of Federal Regulations, 2010 CFR

...false Cardiovascular permanent or temporary pacemaker electrode. 870.3680 Section 870.3680...3680 Cardiovascular permanent or temporary pacemaker electrode. (a) Temporary pacemaker electrode â(1) Identification. A...

2009-04-01

269

21 CFR 870.3680 - Cardiovascular permanent or temporary pacemaker electrode.  

Code of Federal Regulations, 2010 CFR

...false Cardiovascular permanent or temporary pacemaker electrode. 870.3680 Section 870.3680...3680 Cardiovascular permanent or temporary pacemaker electrode. (a) Temporary pacemaker electrode â(1) Identification. A...

2010-04-01

270

Evolutionary innovations in cardiac pacing.  

PubMed

Cardiac pacing has played a significant role in mitigating morbidity and mortality associated with bradyarrhythmias. Throughout the years, advances made in battery reliability, lead performance, and device portability have rapidly expanded the use of cardiac pacemakers in many different disease states. Despite the benefits, there has been growing awareness of the potential deleterious effects of long-term artificial electrical stimulation including the development of ventricular dyssynchrony and atrial fibrillation. Given their association with an increased risk for heart failure and possibly death, several advances aimed at minimizing them have been made in recent years including changes in atrioventricular pacing algorithms, novel pacing mode modifications, and better identification of hemodynamically optimal pacing sites. This article reviews the advances made and the future direction of innovations in cardiac pacing. PMID:21920533

Cheng, Alan; Tereshchenko, Larisa G

2011-01-01

271

Pacemaker lead perforation causing hemopericardium eight years after implantation  

PubMed Central

The number of patients with intracardiac devices, including permanent pacemakers and implantable cardioverter-defibrillators is increasing. Lead perforation is a recognized complication which most often occurs during or shortly following pacemaker implantation. Late lead perforation occurring over 30 days after device insertion is a rare, potentially life-threatening complication. We present a case of late lead perforation unmasked greater than eight years after pacemaker implantation by initiation of anticoagulation.

Liang, Jackson J.; Killu, Ammar M.; Osborn, Michael J.; Jaffe, Allan S.

2013-01-01

272

Nonlinear dynamics, chaos and complex cardiac arrhythmias  

NASA Technical Reports Server (NTRS)

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.

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

1987-01-01

273

Primary batteries for implantable pacemakers and defibrillators  

Microsoft Academic Search

The lithium-iodine battery is established as the standard system for low-rate implantable applications, namely pacemakers because of its excellent volumetric energy density. Within defibrillators\\/cardioverters lithium-silver-oxovanadium (SVO) and lithium-manganese-dioxide (MDX) high-rate batteries are in use. The concept of a hybrid system which makes use of a high-rate battery and a low-rate battery within one application is described. Experimental results obtained from

J. Drews; G. Fehrmann; R. Staub; R. Wolf

2001-01-01

274

Software Simulation of an Implantable Pacemaker  

PubMed Central

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

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

1983-01-01

275

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

276

Pacemaker and ICD leads: strategies for long-term management.  

PubMed

Pacemaker and defibrillator therapy is on the rise as a result of expanding indications. Unfortunately, this trend is associated with an increased number of cardiac device-related complications. Lead failure, device infection and vascular complication are not uncommon and may cause significant patient morbidity and mortality. Furthermore, the considerable variability in the approach to dealing with device-related complications not infrequently leads to additional problems and complications. This review is intended to provide general guidelines and strategies for long-term management of cardiac devices. Proper implantation techniques that focus on primary prevention of complications, as well as, planning for future procedures are essential. The use of sterile techniques and implementation of peri-operative antibiotics are well supported in clinical trials. Additionally, minimizing the amount of implanted hardware and limiting the procedure length have also been shown to decrease the rates of infectious complications. Once device infection is confirmed, the primary objective, short of a few exceptions, should consist of the entire system removal via open surgery or percutaneously and antibiotic therapy before reimplantation. Vascular occlusions are not uncommon; however, in the majority of cases they are asymptomatic. Nonetheless, they pose a significant problem with device reimplantation, especially in the younger patients who will require multiple generator exchanges in the future. Site preservation should, therefore, become the primary objective. This can also be accomplished with the open surgical or percutaneous device removal. The latter is very safe and effective when performed in experienced centers. Finally, lead follow-up must be routinely conducted to identify problematic leads, prevent further reimplantations, and guide future research. PMID:18392929

Borek, P Peter; Wilkoff, Bruce L

2008-10-01

277

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

PubMed Central

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

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

1998-01-01

278

Microgenerators for Energy Autarkic Pacemakers and Defibrillators: Fact or Fiction?  

Microsoft Academic Search

Background: Implantable devices for medical use like permanent pacemakers, defibrillators, and fluid pumps depend on an energy provided by batteries. Unfortunately, the battery usually determines the duration of life of these devices, while technical problems occur infrequent. Device replacement for battery exhaustion requires surgical procedures and account for up to 1\\/3 of all pacemakers sold. Attempts to provide unlimited power

Günter Görge; Michael Kirstein; Raimund Erbel

2001-01-01

279

Laser welding in the manufacture of heart pacemakers  

NASA Astrophysics Data System (ADS)

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

Janssen, G. W. G.

280

Programming a fixed long atrioventricular delay is not effective in preventing ventricular pacing in patients with sick sinus syndrome  

Microsoft Academic Search

Aim Most patients with sick sinus syndrome (SSS) and normal atrioventricular (AV) conduction receive dual chamber (DDDR) pacemakers. Programming a long AV delay has been proposed to avoid ventricular pacing. The present study aimed to evaluate ventricular stimulation in SSS patients with DDDR pacemakers with a long AV delay.Methods and Results Thirty eight patients treated with DDDR pacemakers with a

J. C. Nielsen; A. K. Pedersen; P. T. Mortensen; H. R. Andersen

1999-01-01

281

Programming a fixed long atrioventricular delay is not effective in preventing ventricular pacing in patients with sick sinus syndrome  

Microsoft Academic Search

Aim Most patients with sick sinus syndrome (SSS) and normal atrioventricular (AV) conduction receive dual chamber (DDDR) pacemakers. Programming a long AV delay has been proposed to avoid ventricular pacing. The present study aimed to evaluate ventricular stimulation in SSS patients with DDDR pacemakers with a long AV delay. Methods and Results Thirty eight patients treated with DDDR pacemakers with

J. C. Nielsen; A. K. Pedersen; P. T. Mortensen; H. R. Andersen

282

Use of pacemaker programmers for disaster victim identification.  

PubMed

Disaster victim identification (DVI) presents a number of physical and legal challenges, involving the degeneration of human remains and legal obstacles to forensic examinations. One non-invasive method for positive identification may be the use of a pacemaker programmer to detect and obtain data from pacemakers recovered from unidentified remains. To test the usefulness of this method, this investigation examined the efficiency and utility of 5 different pacemaker programmers in the positive identification of victims of the March 2011 tsunami in Japan at 8 disaster sites in May 2011. On scanning 148 sets of remains, data were successfully obtained from 1 implant in 1 set of remains, allowing for the rapid positive identification of the individual. Scanning pacemakers with pacemaker programmers can be a non-invasive method of positive identification that meets Japanese legal and institutional requirements, but this method is ineffective without a preceding whole-body X-ray scan. PMID:23592022

Makinae, Haruka; Numata, Norio; Kitaoka, Hirofumi; Daimon, Masao; Yamamoto, Taira; Amano, Atsushi

2013-12-01

283

[What the internist needs to know about pacemakers].  

PubMed

In Switzerland, in 2011, 4463 patients underwent pacemaker implantation. This review article focusses on basic pacemaker functions, some fundamental remarks on pacemaker therapy and especially indications and pacemaker models. The current guidelines for PM indications date from the years 2007 [1] and 2008 [2] and form the basis of this article. Very rare indications (congenital heart disease, bradycardia after heart transplantation) are not discussed. Each year, new pacemaker models are released that provide advanced diagnostic features (e. g. detailed heart rate memory, 1:1 ECG recordings). However, these features do not significantly change everyday practice. An innovation with clinical impact is the "MRI-safe" system that has been introduced about a year ago. PMID:23919940

Nüssli, Dominique; Schär, Beat

2013-08-01

284

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

ERIC Educational Resources Information Center

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…

Wilson, Philip K.; Hall, Linda K.

1984-01-01

285

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

PubMed

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

Fukuta, Motoyuki; Mizutani, Noboru; Waseda, Katsuhisa

2005-01-01

286

A narrative review on women and cardiac rehabilitation: program adherence and preferences for alternative models of care.  

PubMed

Despite the preponderance of evidence on the numerous benefits of CR, it remains largely under-utilized in women. The objective of this narrative review was to summarize and synthesize the literature on women and CR with regard to outcomes, adherence, and preferences for alternative models of CR. Studies of the effectiveness of CR have generally revealed no major differences between men and women. However, female-specific data are lacking on the effect of CR on mortality and morbidity. Research suggests that women and men may be equally likely to prefer home-based to hospital-based CR services. Women's preferences for and outcomes in, women-only CR are beginning to be uncovered. Discussing program model options with female cardiac patients and referring to preferred types may be the appropriate approach until further evidence is available. PMID:20678874

Grace, Sherry L; Racco, Cassandra; Chessex, Caroline; Rivera, Tiziana; Oh, Paul

2010-11-01

287

A prospective audit of pacemaker function, implant lifetime, and cause of death in the patient  

Microsoft Academic Search

AIM: To audit prospectively the reasons for pacemaker implantation, the duration of the pacemaker use, the cause of death, and pacemaker function after removal from the patient. METHODS: Pacemakers were removed at necropsy, or from the bodies of patients awaiting cremation, in three hospitals over a three year period. The cause of death was taken from the results of the

S. K. Suvarna; R. D. Start; D. I. Tayler

1999-01-01

288

Unusual case of colonized pacemaker lead presenting with endocarditis, hemoptysis and tricuspid valve stenosis.  

PubMed

The present report is the first to describe a case of hemoptysis caused by an endocardial pacemaker lead. In addition, the patient presented with endocarditis and tricuspid valve stenosis. Aggressive treatment consisted of surgical extraction of two pacemaker leads and one pacemaker battery, replacement of the tricuspid valve and implantation of a DDD-R epicardial pacemaker. PMID:21766083

Morin, Jean-Francois; Sheppard, Richard; Chamoun, Patrick

2011-01-01

289

An Evaluation of Technologies for Identifying Acute Cardiac Ischemia in the Emergency Department: A Report from a National Heart Attack Alert Program Working Group  

Microsoft Academic Search

[Selker HP, Zalenski RJ, Antman EM, Aufderheide TP, Bernard SA, Bonow RO, Gibler WB, Hagen MD, Johnson P, Lau J, McNutt RA, Ornato J, Schwartz JS, Scott JD, Tunick PA, Weaver WD: An evaluation of technologies for identifying acute cardiac ischemia in the emergency department: A report from a National Heart Attack Alert Program Working Group. Ann Emerg Med January

Harry P Selker; Robert J Zalenski; Elliott M Antman; Tom P Aufderheide; Sheilah Ann Bernard; Robert O Bonow; W. Brian Gibler; Michael D Hagen; Paula Johnson; Joseph Lau; Robert A McNutt; Joseph Ornato; J. Sanford Schwartz; Jane D Scott; Paul A Tunick; W. Douglas Weaver

1997-01-01

290

An Evaluation of Technologies for Identifying Acute Cardiac Ischemia in the Emergency Department: Executive Summary of a National Heart Attack Alert Program Working Group Report  

Microsoft Academic Search

[Selker HP, Zalenski RJ, Antman EM, Aufderheide TP, Bernard SA, Bonow RO, Gibler WB, Hagen MD, Johnson P, Lau J, McNutt RA, Ornato J, Schwartz JS, Scott JD, Tunick PA, Weaver WD: An evaluation of technologies for identifying acute cardiac ischemia in the emergency department: Executive Summary of a National Heart Attack Alert Program Working Group report. Ann Emerg Med

Harry P Selker; Robert J Zalenski; Elliott M Antman; Tom P Aufderheide; Sheilah Ann Bernard; Robert O Bonow; W. Brian Gibler; Michael D Hagen; Paula Johnson; Joseph Lau; Robert A McNutt; Joseph Ornato; J. Sanford Schwartz; Jane D Scott; Paul A Tunick; W. Douglas Weaver

1997-01-01

291

Thallium cardiac stressing by esophageal pacing  

SciTech Connect

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

Allen, M.L.; Vacek, J.L.; Preston, D.F.; Robinson, R.G.; Feldkamp, M.J. (Univ. of Kansas Medical Center, Kansas City (USA))

1989-09-01

292

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

NASA Astrophysics Data System (ADS)

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

Armbruster, John M.

2011-06-01

293

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

SciTech Connect

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.

Armbruster, John M. [IBA Molecular, NA, 3601 Morgantown Industrial Park, Morgantown, WV 26501 (United States)

2011-06-01

294

Technology utilization program report  

NASA Technical Reports Server (NTRS)

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.

1974-01-01

295

[Pacemaker and implantable defibrillators with telemedical support].  

PubMed

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

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

2009-03-01

296

Safe magnetic resonance image scanning of the pacemaker patient: current technologies and future directions.  

PubMed

Magnetic resonance imaging (MRI) is the imaging modality of choice in many clinical situations, and its use is likely to grow due to expanding indications and an ageing population. Many patients with implantable devices are denied MRI except in cases of urgent need, and when scans must be performed they are complicated by the need for burdensome and costly personnel and monitoring requirements that have the net effect of restricting access to scans. Several small studies, enrolling a total of 344 patients, suggest that some patients with conventional systems may undergo MR examinations without clinically overt adverse events. However, a number of potential interactions exist between implantable cardiac devices and the static and gradient magnetic fields and modulated radio frequency (RF) fields generated during MR scans; nearly all studies have reported pacing capture threshold changes, troponin elevations, ectopy, unpredictable reed switch behaviour, and other 'subclinical' issues with pacemakers and implantable cardioverter-defibrillators (ICDs) in patients who have undergone MRI. Attention has turned to devices that are specifically designed to be safe in the MRI environment. A clinical study of one such device documented its ability to be exposed to MRI in a 1.5 T scanner without adverse impact on patient outcomes or pacemaker system function. Such new technologies may enable scanning of pacemaker and ICD patients with reduced concerns regarding the short- and long-term effects of MRI. As importantly, these devices may increase the number of centres that are able to safely perform MRI and, thus, expand access to scans for patients with these devices. PMID:22237585

Jung, Werner; Zvereva, Vlada; Hajredini, Bajram; Jäckle, Sebastian

2012-05-01

297

The Effects of a Tailored Cardiac Rehabilitation Program on Depressive Symptoms in Women: A Randomized Clinical Trial  

PubMed Central

Background Depression is known to co-occur with coronary heart disease (CHD). Depression may also inhibit the effectiveness of cardiac rehabilitation (CR) programs by decreasing adherence. Higher prevalence of depression in women may place them at increased risk for non-adherence. Objective To assess the impact of a modified, stage-of-change-matched, gender-tailored CR program for reducing depressive symptoms among women with CHD. Methods A 2-group randomized clinical trial compared depressive symptoms of women in a traditional 12-week CR program to those completing a tailored program that included motivational interviewing guided by the Transtheoretical Model of behavior change. Women in the experimental group also participated in a gender-tailored exercise protocol that excluded men. The Center for Epidemiological Studies Depression (CES-D) Scale was administered to 225 women at baseline, post-intervention, and at 6-month follow-up. Analysis of Variance was used to compare changes in depression scores over time. Results Baseline CES-D scores were 17.3 and 16.5 for the tailored and traditional groups, respectively. Post-intervention mean scores were 11.0 and 14.3; Six-month follow-up scores were 13.0 and 15.2, respectively. A significant group by time interaction was found for CES-D scores (F(2, 446) = 4.42, p = .013). Follow-up tests revealed that the CES-D scores for the traditional group did not differ over time (F(2, 446) = 2.00, p = .137). By contrast, the tailored group showed significantly decreased CES-D scores from baseline to post-test (F(1, 223) = 50.34, p < .001); despite the slight rise from post-test to 6-month followup, CES-D scores remained lower than baseline (F(1, 223) = 19.25, p < .001). Conclusion This study demonstrated that a modified, gender-tailored CR program reduced depressive symptoms in women when compared to a traditional program. To the extent that depression hinders CR adherence, such tailored programs have potential to improve outcomes for women by maximizing adherence. Future studies should explore the mechanism by which such programs produce benefits.

Beckie, Theresa M.; Beckstead, Jason W.; Schocken, Douglas D.; Evans, Mary E.; Fletcher, Gerald F.

2014-01-01

298

Does the presence or absence of sonographically identified cardiac activity predict resuscitation outcomes of cardiac arrest patients?  

Microsoft Academic Search

This study evaluated the ability of cardiac sonography performed by emergency physicians to predict resuscitation outcomes of cardiac arrest patients. A convenience sample of cardiac arrest patients prospectively underwent bedside cardiac sonography at 4 emergency medicine residency–affiliated EDs as part of the Sonography Outcomes Assessment Program. Cardiac arrest patients in pulseless electrical activity (PEA) and asystole underwent transthoracic cardiac ultrasound

Philip Salen; Larry Melniker; Carolyn Chooljian; John S. Rose; Janet Alteveer; James Reed; Michael Heller

2005-01-01

299

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

PubMed Central

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

2013-01-01

300

Diabetes mellitus activates fetal gene program and intensifies cardiac remodeling and oxidative stress in aged spontaneously hypertensive rats  

PubMed Central

Background The combination of systemic arterial hypertension and diabetes mellitus (DM) induces greater cardiac remodeling than either condition alone. However, this association has been poorly addressed in senescent rats. Therefore, this study aimed to analyze the influence of streptozotocin-induced DM on ventricular remodeling and oxidative stress in aged spontaneously hypertensive rats (SHR). Methods Fifty 18 month old male SHR were divided into two groups: control (SHR, n?=?25) and diabetic (SHR-DM, n?=?25). DM was induced by streptozotocin (40 mg/kg, i.p.). After nine weeks, the rats underwent echocardiography and myocardial functional study in left ventricular (LV) isolated papillary muscle preparations. LV samples were obtained to measure myocyte diameters, interstitial collagen fraction, and hydroxyproline concentration. Gene expression of atrial natriuretic peptide (ANP) and ?- and ?-myosin heavy chain (MyHC) isoforms was evaluated by RT-PCR. Serum oxidative stress was assessed by measuring lipid hydroperoxide concentration and superoxide dismutase and glutathione peroxidase activities. Statistics: Student’s t test or Mann-Whitney test, p?cardiac dilation and functional impairment, increases oxidative stress and activates fetal gene program in aged spontaneously hypertensive rats.

2013-01-01

301

[Incomplete pacemaker lead fracture revealed by superficial maneuvers].  

PubMed

A 75-year-old man presented to our department with a complaint of recurrent syncope episodes seven years after dual chamber pacemaker implantation due to complete atrioventricular block. His electrocardiogram obtained on presentation showed a normal dual-chamber pacemaker rhythm. The chest X-ray and pacemaker interrogation did not show any lead fracture or dysfunction. Twenty-four hour Holter monitoring revealed periods of failure to pacing. Superficial maneuvers over the skin resulted in an excessive increase in the ventricular lead impedance and pacing failure. The clinical course of the patient was uneventful after implantation of a new electrode to the right ventricular apex. PMID:21200109

Aksoy, Hakan; Okutucu, Sercan; Karakulak, U?ur N; Atalar, Enver

2010-07-01

302

Subacute presentation of right ventricular perforation after pacemaker implantation.  

PubMed

We report an 87-year-old woman with right ventricular perforation due to a permanent pacemaker lead detected 4-days after implantation. The pacemaker lead was seen to perforate through the myocardium and pericardium and to reach the left pleural cavity. We removed the wire surgically by median sternotomy. The pericardial effusion was cloudy and yellowish, suggesting infection. However, no bacteria were detected by bacterial cultures of the pericardial effusion and pacing wire. The patient developed neither mediastinitis nor sepsis after the operation, and a new pacemaker was implanted safely one month later. PMID:22673606

Koyama, Sachi; Itatani, Keiichi; Kyo, Shunei; Aoyama, Rie; Ishiyama, Taizo; Harada, Kazumasa; Ono, Minoru

2013-02-20

303

Dual chamber pacemaker with adaptive atrial escape interval  

US Patent & Trademark Office Database

A dual chamber pacemaker having an atrial escape interval which is varied on a beat-to-beat basis in response to the measured time from a ventricular event to the next atrial sensed event. Additionally, a portion of the atrial escape interval is bifurcated into a first sensing portion T1 and a second sensing portion T2 wherein atrial sense events occurring during T1 may be ignored by the pacemaker, while atrial sense events falling within T2 are used to compute a new atrial escape interval and are used to resynchronize the pacemaker and are used to inhibit the otherwise scheduled atrial pace event.

1990-05-01

304

Socioeconomic Status and Improvements in Lifestyle, Coronary Risk Factors, and Quality of Life: The Multisite Cardiac Lifestyle Intervention Program  

PubMed Central

Objectives. We sought to clarify whether patients of low socioeconomic status (SES) can make lifestyle changes and show improved outcomes in coronary heart disease (CHD), similar to patients with higher SES. Methods. We examined lifestyle, risk factors, and quality of life over 3 months, by SES and gender, in 869 predominantly White, nonsmoking CHD patients (34% female) in the insurance-sponsored Multisite Cardiac Lifestyle Intervention Program. SES was defined primarily by education. Results. At baseline, less-educated participants were more likely to be disadvantaged (e.g., past smoking, sedentary lifestyle, high fat diet, overweight, depression) than were higher-SES participants. By 3 months, participants at all SES levels reported consuming 10% or less dietary fat, exercising 3.5 hours per week or more, and practicing stress management 5.5 hours per week or more. These self-reports were substantiated by improvements in risk factors (e.g., 5-kg weight loss, and improved blood pressure, low-density lipoprotein cholesterol, and exercise capacity; P < .001), and accompanied by improvements in well-being (e.g., depression, hostility, quality of life; P < .001). Conclusions. The observed benefits for CHD patients with low SES indicate that broadening accessibility of lifestyle programs through health insurance should be strongly encouraged.

Govil, Sarah R.; Merritt-Worden, Terri; Ornish, Dean

2009-01-01

305

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

PubMed Central

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 × [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) (t29 = 12.81, P < 0.001) and significantly higher than the suggested maximum of 150 beats/min during cardiac rehabilitation training (t29 = 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 (t29 = 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.

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

2010-01-01

306

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

PubMed

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

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

2014-01-01

307

Biological pacemaker engineered by nonviral gene transfer in a mouse model of complete atrioventricular block.  

PubMed

We hypothesized that a nonviral gene delivery of the hyperpolarization-activated HCN2 channel combined with the beta(2)-adrenergic receptor (ADRB2) would generate a functional pacemaker in a mouse model of complete atrioventricular block (CAVB) induced by radiofrequency ablation of the His bundle. Plasmids encoding HCN2 and ADRB2 mixed with tetronic 304, a poloxamine block copolymer, were injected in the left ventricular free wall (HCN2-ADRB2 mice). Sham mice received a noncoding plasmid. CAVB was induced 5 days later. Ventricular escape rhythms in HCN2-ADRB2 mice were significantly faster than in sham mice at day 15 after ablation and later. In HCN2-ADRB2 mice, QRS complexes were larger than in sham mice and characterized by abnormal axes. Immunostaining of GFP-HCN2 fusion protein showed an expression of HCN2 channel in left ventricular myocardium for at least 45 days after injection. In the mouse, CAVB induces progressive hypertrophy and heart failure leading to 50% mortality after 110 days. HCN2-ADRB2 mice survived 3 weeks longer than sham mice. Finally, beta-adrenergic input increased ventricular escape rhythms significantly more in HCN2-ADRB2 mice than in sham mice. In conclusion, nonviral gene transfer can produce a functional cardiac biological pacemaker regulated by sympathetic input, which improves life expectancy in a mouse model of CAVB. PMID:18813278

Piron, Julien; Quang, Khai Le; Briec, François; Amirault, Jean-Christophe; Leoni, Anne-Laure; Desigaux, Léa; Escande, Denis; Pitard, Bruno; Charpentier, Flavien

2008-12-01

308

National Heart Attack Alert Program Position Paper: Chest Pain Centers and Programs for the Evaluation of Acute Cardiac Ischemia  

Microsoft Academic Search

The National Heart Attack Alert Program (NHAAP), which is coordinated by the National Heart, Lung, and Blood Institute (NHLBI), promotes the early detection and optimal treatment of patients with acute myocardial infarction and other acute coronary ischemic syndromes. The NHAAP, having observed the development and growth of chest pain centers in emergency departments with special interest, created a task force

Robert J. Zalenski; Harry P. Selker; Christopher P. Cannon; Helke M. Farin; W. Brian Gibler; Robert J. Goldberg; Costas T. Lambrew; Joseph P. Ornato; Robert J. Rydman; Pamela Steele

2000-01-01

309

Rehabilitation of Cardiac Patients.  

National Technical Information Service (NTIS)

The five and one-half year study to evaluate methods of rehabilitating cardiac patients found that programs for rehabilitation must be individualized according to preconditions and guidelines given in detail in the report. The yoga exercise 'Shavasan' was...

K. K. Datey

1974-01-01

310

Changes of autonomic cardiac profile after a 3-week integrated body weight reduction program in severely obese patients.  

PubMed

The autonomic control of the heart is abnormal in obese subjects due to a prevalence of sympathetic over parasympathetic limb of the autonomic balance. We evaluated the effects of a short-term (3 weeks) integrated body weight reduction program (consisting of energy restricted diet and high-intensity exercise training) on heart rate variability (HRV) in severely obese, normotensive patients. The HRV was evaluated both in the time and frequency domain over a 18-hour Holter recording period obtained before and at the end of the third week. Three-week body weight reduction program reduced BMI (from 41.4 +/- 4.6 to 39.5 +/- 4.3 kg/m2, -4.6%, p<0.0001) and heart rate (from 77.8 +/- 8.6 to 73.6 +/- 8.7 b/min, p=0.0003). Significant changes in the autonomic profile were observed both in the time and frequency domain (SD of RR interval, SDRR: +16.1%; mean squared successive difference: (MSSD) +16.7%; percentage of RR intervals differing more than 50 msec from the preceding one, pNN50: +31.8%; low frequency oscillation, LF: +17.1%; high frequency oscillation, HF: +/- 18.2%). In conclusion, this study demonstrates that a short-term, integrated body weight reduction program is able to favorably modify the autonomic profile in a population of normotensive, severely obese subjects. The reduction of heart rate and the increase in parasympathetic activity may consistently contribute to a reduction of the risk of cardiovascular morbidity and of sudden cardiac death, still high in this patients' group. PMID:12739741

Facchini, M; Malfatto, G; Sala, L; Silvestri, G; Fontana, P; Lafortuna, C; Sartorio, A

2003-02-01

311

Surgical Management of the Patient with an Implanted Cardiac Device  

PubMed Central

Objective To identify the sources of electromagnetic interference (EMI) that may alter the performance of implanted cardiac devices and develop strategies to minimize their effects on patient hemodynamic status. Summary Background Data Since the development of the sensing demand pacemaker, EMI in the clinical setting has concerned physicians treating patients with such devices. Implanted cardiovertor defibrillators (ICDs) and ventricular assist devices (VADs) can also be affected by EMI. Methods All known sources of interference to pacemakers, ICDs, and VADs were evaluated and preventative strategies were devised. Results All devices should be thoroughly evaluated before and after surgery to make sure that its function has not been permanently damaged or changed. If electrocautery is to be used, pacemakers should be placed in a triggered or asynchronous mode; ICDs should have arrhythmia detection suspended before surgery. If defibrillation is to be used, the current flow between the paddles should be kept as far away from and perpendicular to the lead system as possible. Both pacemakers and ICDs should be properly shielded if magnetic resonance imaging, positron emission tomography, or radiation therapy is to be used. The effect of EMI on VADs depends on the model. Magnetic resonance imaging adversely affects all VADs except the Abiomed VAD, and therefore its use should be avoided in this population of patients. Conclusions The patient with an implanted cardiac device can safely undergo surgery as long as certain precautions are taken.

Madigan, John D.; Choudhri, Asim F.; Chen, Jonathan; Spotnitz, Henry M.; Oz, Mehmet C.; Edwards, Niloo

1999-01-01

312

Flexibility and Strength Measures in Children Participating in a Cardiac Rehabilitation Exercise Program.  

ERIC Educational Resources Information Center

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)

Koch, Barbara M.; And Others

1988-01-01

313

Exercise Programming for Cardiacs--A New Direction for Physical Therapists.  

ERIC Educational Resources Information Center

This speech begins with the presentation of a conceptual scheme of the physical working capacity of a person starting a training program. The scheme shows that after exercise, when recovery begins and sufficient time elapses, the individual recovers and adapts to a level of physical working capacity which is higher than his starting level. From…

Gutin, Bernard

314

Endocardial Pacemaker Implantation in Neonates and Infants  

PubMed Central

Transvenous pacemaker lead implantation is the preferred method of pacing in adult patients. Lead performance and longevity are superior and the implantation approach can be performed under local anaesthetic with a very low morbidity. In children, and especially in neonates and infants, the epicardial route was traditionally chosen until the advent of smaller generators and lead implantation techniques that allowed growth of the child without lead displacement. Endocardial implantation is not universally accepted, however, as there is an incidence of venous occlusion of the smaller veins of neonates and infants with concerns for loss of venous access in the future. Growing experience with lower profile leads, however, reveals that endocardial pacing too can be performed with low morbidity and good long-term results in neonates and infants.

Ayabakan, Canan; Rosenthal, Eric

2006-01-01

315

A functional analysis of circadian pacemakers in nocturnal rodents  

Microsoft Academic Search

Summary 1.The circadian pacemakers controlling activity rhythms in four species of rodents are compared, as freerunning systems in constant darkness. In analyzing their stability the distinction is made between (1) spontaneous day-to-day instability of frequency, and (2) a longer-term lability, some of which is traceable to identified causes.2.Serial correlation analysis indicates that the precision (day-to-day stability) of the pacemaker's period

Colin S. Pittendrigh; Serge Daan

1976-01-01

316

Role of dual pacemaker mechanisms in sinoatrial node discharge  

Microsoft Academic Search

We investigated whether in the sinoatrial node (SAN) there are two different pacemaker mechanisms and whether either one can maintain spontaneous discharge. These questions were studied by means of an electrophysiological technique and of blockers of different diastolic currents in rabbit and guinea pig isolated SAN. In SAN subsidiary pacemakers of both species, Cs+ (5–10 mM) or high [K+]o (10–12

Hengtao Zhang; Mario Vassalle

2000-01-01

317

Irreversible third-degree heart block and pacemaker implant in a case of flecainide toxicity.  

PubMed

An 82-year-old white woman was seen in the emergency department (ED) after ingesting 400 mg of flecainide in an attempt to treat an episode of dizziness and palpitations that occurred while she was gardening. Consequently, she developed bradycardia, hypotension, and complete heart block. In addition to supportive care, she also received sodium bicarbonate, atropine, calcium gluconate, and dopamine in an effort to reverse the heart block. The patient continued to remain in heart block and was sent to the cardiac catheterization laboratory for placement of an external pacing wire, which stabilized the patient. After further evaluation, a permanent pacemaker was implanted during her admission. External pacing wires may be useful in the treatment of complete heart block in cases of flecainide poisoning when a patient is unresponsive to drug therapy provided in the ED. PMID:23810074

Lloyd, Thomas; Zimmerman, Jacob; Griffin, Gregory D

2013-09-01

318

Cardiac pacing and aviation.  

PubMed

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

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

1992-12-01

319

Pacemakers handshake synchronization mechanism of mammalian respiratory rhythmogenesis.  

PubMed

Inspiratory and expiratory rhythms in mammals are thought to be generated by pacemaker-like neurons in 2 discrete brainstem regions: pre-Bötzinger complex (preBötC) and parafacial respiratory group (pFRG). How these putative pacemakers or pacemaker networks may interact to set the overall respiratory rhythm in synchrony remains unclear. Here, we show that a pacemakers 2-way "handshake" process comprising pFRG excitation of the preBötC, followed by reverse inhibition and postinhibitory rebound (PIR) excitation of the pFRG and postinspiratory feedback inhibition of the preBötC, can provide a phase-locked mechanism that sequentially resets and, hence, synchronizes the inspiratory and expiratory rhythms in neonates. The order of this handshake sequence and its progression vary depending on the relative excitabilities of the preBötC vs. the pFRG and resultant modulations of the PIR in various excited and depressed states, leading to complex inspiratory and expiratory phase-resetting behaviors in neonates and adults. This parsimonious model of pacemakers synchronization and mutual entrainment replicates key experimental data in vitro and in vivo that delineate the developmental changes in respiratory rhythm from neonates to maturity, elucidating their underlying mechanisms and suggesting hypotheses for further experimental testing. Such a pacemakers handshake process with conjugate excitation-inhibition and PIR provides a reinforcing and evolutionarily advantageous fail-safe mechanism for respiratory rhythmogenesis in mammals. PMID:19008356

Wittmeier, Steffen; Song, Gang; Duffin, James; Poon, Chi-Sang

2008-11-18

320

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

SciTech Connect

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

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

1984-10-01

321

Real-time confocal raman imaging of a drug delivery system on cardiac leads  

Microsoft Academic Search

Drug delivery systems incorporated onto the end of cardiac leads are used to reduce inflammation and fibrosis at the lead-tissue interface and enable optimal lead performance. In this research, confocal Raman microscopy was used to capture chemical images of the drug delivery system on pacemaker leads in different elution media in real-time. Raman images in ambient air showed that drug

Jinping Dong; J. Polkinghorne; R. Heil; R. Kemp

2009-01-01

322

Software for characterizing the ionic basis of the molluscan cardiac action potential  

Microsoft Academic Search

The goal of this modeling effort was to examine how individual membrane currents determine the repertoire of electrical signals recorded from bivalve cardiac action potentials. Software was developed in C++ (for both PC and Macintosh) and Java (Internet). A series of Hodgkin-Huxley equations described the kinetics of pacemaker activity, while a degree of customization was incorporated into the simulation, enabling

Ying Sun; L. P. Collis; R. B. Hill

2000-01-01

323

Evaluation of a self-management patient education program for patients with chronic heart failure undergoing inpatient cardiac rehabilitation: study protocol of a cluster randomized controlled trial  

PubMed Central

Background Chronic heart failure requires a complex treatment regimen on a life-long basis. Therefore, self-care/self-management is an essential part of successful treatment and comprehensive patient education is warranted. However, specific information on program features and educational strategies enhancing treatment success is lacking. This trial aims to evaluate a patient-oriented and theory-based self-management educational group program as compared to usual care education during inpatient cardiac rehabilitation in Germany. Methods/Design The study is a multicenter cluster randomized controlled trial in four cardiac rehabilitation clinics. Clusters are patient education groups that comprise HF patients recruited within 2 weeks after commencement of inpatient cardiac rehabilitation. Cluster randomization was chosen for pragmatic reasons, i.e. to ensure a sufficient number of eligible patients to build large-enough educational groups and to prevent contamination by interaction of patients from different treatment allocations during rehabilitation. Rehabilitants with chronic systolic heart failure (n?=?540) will be consecutively recruited for the study at the beginning of inpatient rehabilitation. Data will be assessed at admission, at discharge and after 6 and 12 months using patient questionnaires. In the intervention condition, patients receive the new patient-oriented self-management educational program, whereas in the control condition, patients receive a short lecture-based educational program (usual care). The primary outcome is patients’ self-reported self-management competence. Secondary outcomes include behavioral determinants and self-management health behavior (symptom monitoring, physical activity, medication adherence), health-related quality of life, and treatment satisfaction. Treatment effects will be evaluated separately for each follow-up time point using multilevel regression analysis, and adjusting for baseline values. Discussion This study evaluates the effectiveness of a comprehensive self-management educational program by a cluster randomized trial within inpatient cardiac rehabilitation in Germany. Furthermore, subgroup-related treatment effects will be explored. Study results will contribute to a better understanding of both the effectiveness and mechanisms of a self-management group program as part of cardiac rehabilitation. Trial registration German Clinical Trials Register: DRKS00004841; WHO International Clinical Trials: = DRKS00004841

2013-01-01

324

Use of a comprehensive numerical model to improve biventricular pacemaker temporization in patients affected by heart failure undergoing to CRT-D therapy.  

PubMed

Cardiac resynchronization therapy by biventricular pacemaker/ICD implantation is a validated therapy for patients affected by heart failure with asynchrony of ventricular contraction. Considering the large number of parameters which play a role in cardiac resynchronization therapy, a comprehensive numerical model of cardiocirculatory system could be a useful tool to support clinical decisions. A variable elastance model of ventricles was updated to model the interventricular septum and to simulate the interventricular and the intraventricular desynchrony, and the effect of the biventricular stimulation. In addition, a numerical model of the biventricular pacemaker, which drives the beginning of the heart chambers and interventricular septum contraction, was also developed. In order to validate the model, five patients affected by dilated cardiomyopathy were analysed by echocardiography and electrocardiography before implantation, 24 h and 3 months after the implantation. The developed numerical model permits to reproduce clinical data and to estimate the trend of parameters that are difficult to measure (i.e. left ventricular systolic elastance). Furthermore, the model permits to study the effect of different biventricular pacemaker temporizations on hemodynamic variables. PMID:20617393

Di Molfetta, A; Santini, L; Forleo, G B; Cesario, M; Tota, C; Sgueglia, M; Sergi, D; Ferrari, G; Romeo, F

2010-08-01

325

Home-Based Cardiac Rehabilitation.  

ERIC Educational Resources Information Center

Although cardiac rehabilitation has become increasingly popular, only 15 percent of eligible candidates participate in supervised and monitored programs. This article reviews alternative home-based cardiac rehabilitation, discussing types of activities, monitoring, diet, motivation, and coordination with traditional program staff. (Author/MT)

Fardy, Paul S.

1987-01-01

326

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

PubMed

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

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

2012-12-01

327

A new program of kidney transplantation from donors after cardiac death in Spain.  

PubMed

Despite the high rate of kidney transplantation in Spain, a disparity still exists between the numbers of donors and waiting-list patients. Donors after circulatory death (DCD) have been propagated as a promising approach to reduce the donor kidney shortage. In Europe most of the countries use controlled DCD, but in Spain, mainly uncontrolled DCD are harvested and until 2010 at only four institutions. In January 2010, we began a program of donation after uncontrolled DCD (Maastricht type II; unsuccessful resuscitation). The aim of this observational study was to describe our preliminary results. The numbers of recovered and transplanted organs per DCD were 27. There were no cases of primary nonfunction, but delayed graft function was present in 85% of recipients. Despite this impairment, about 75% of patients reached a serum creatinine below 2 mg/dL in the second month, with 1-year graft and patient survivals of 85% and 100%. Although, our preliminary results with a not very long follow-up and small number of patients suggested that utilization of DCD should be expanded because this type of donor increases the number of cases and opportunities of end-stage renal disease patients to reduce the waiting times for transplantation. PMID:23146441

de Gracia, M C; Osorio, J M; Pérez-Villares, J M; Galindo, P; Ruiz, M C; Pérez-Marfil, A; Bravo, J; Osuna, A

2012-11-01

328

Scientists Use Gene Therapy to Create 'Biological Pacemaker' in Pig Hearts  

MedlinePLUS

... enable JavaScript. Scientists Use Gene Therapy to Create 'Biological Pacemaker' in Pig Hearts Technique might one day ... transform ordinary pig heart muscle cells into a "biological pacemaker," a feat that might one day lead ...

329

Spiral-pacemaker interactions in a mathematical model of excitable medium  

NASA Astrophysics Data System (ADS)

Interactions of a spiral wave with a pacemaker is studied in a mathematical model of two dimensional excitable medium. Faster pacemakers emitting target waves can abolish spirals by driving them to the border of the medium. Our study shows that a slower pacemaker can modify spiral wave behavior by changing the motion of the spiral core. We analyze the dynamics of the spiral wave near the spiral core and away from the core as a function of size and period of the pacemaker. The pacemaker can cause the spiral wave to drift towards it, and either speed up or slow down the reentrant activity. Furthermore, the drift induced by the pacemaker can result in irregular or quasiperiodic dynamics even at sites away from the pacemaker. These results highlight the influence of pacemakers on complex spiral wave dynamics.

Shajahan, T. K.; Borek, Bart?omiej; Shrier, Alvin; Glass, Leon

2013-02-01

330

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

PubMed

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

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

2014-01-01

331

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

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.

Cottrell, Lesley; Murphy, Emily; Lilly, Christa L.; Ritchie, Susan K.; Minor, Valerie; Neal, William A.

2013-01-01

332

[Update on indications for cardiac resynchronization therapy].  

PubMed

Cardiac resynchronization therapy (CRT) is a recognized treatment for patients with systolic heart failure, dyspnea with NYHA class II-IV despite optimal medical treatment, ejection fraction < or =35% and QRS duration > or =120 ms. This article reviews and comments upon the latest pacemaker guidelines by the European Society of Cardiology that were updated in 2013. The main changes in these guidelines are to take into account QRS morphology to optimize patient selection, and to prescribe CRT in patients requiring frequent ventricular pacing and reduced ejection fraction, irrespective of baseline ORS duration and heart failure status. PMID:24964528

Schukraft, S; Burri, H

2014-05-28

333

[Dying with/despite a pacemaker].  

PubMed

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

Reith, S; Janssens, U

2014-02-01

334

The neurochemical basis of photic entrainment of the circadian pacemaker  

NASA Technical Reports Server (NTRS)

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.

Rea, Michael A.; Buckley, Becky; Lutton, Lewis M.

1992-01-01

335

Linear and nonlinear energy harvesters for powering pacemakers from heart beat vibrations  

Microsoft Academic Search

Linear and nonlinear piezoelectric devices are introduced to continuously recharge the batteries of the pacemakers by converting the vibrations from the heartbeats to electrical energy. The power requirement of the pacemakers is very low. At the same time, after about 10 years from the original implantation of the pacemakers, patients have to go through another surgical operation just to replace

M. Amin Karami; Daniel J. Inman

2011-01-01

336

Use of an active fixation lead and a subpectoral pacemaker pocket may not avoid Twiddler's syndrome.  

PubMed

Manipulation of a pacemaker with consequent malfunction of the device has been called Twiddler's syndrome. Use of active-fixation leads and subpectoral pacemaker pockets has been considered to help in avoiding this problem. We describe a child in whom twiddling was not prevented despite implantation of a lumenless atrial lead and insertion of the pacemaker generator in a subpectoral pocket. PMID:23129916

Udink Ten Cate, Floris E A; Adelmann, Roland; Schmidt, Beate E; Sreeram, Narayanswami

2012-07-01

337

Septic paradoxical embolus through a patent foramen ovale after pacemaker implantation  

Microsoft Academic Search

A case of a septic paradoxic embolus due to an infected pacemaker lead associated with a patent foramen ovale (PFO) is described. Treatment consisted of immediate intracardiac embolectomy, pericardial patch closure of the PFO, total removal of the infected pacemaker lead and generator, and placement of a new permanent epicardial lead pacemaker system.

David E Allie; Mitchell D Lirtzman; Charles H Wyatt; Dennis A Vitrella; Craig M Walker

2000-01-01

338

Mechanism of Pacemaking in IK1-Downregulated Myocytes  

PubMed Central

Biological pacemakers were recently created by genetic suppression of inward rectifier potassium current, IK1, in guinea pig ventricular cells. We simulated these cells by adjusting IK1 conductance in the Luo-Rudy model of the guinea pig ventricular myocyte. After 81% IK1 suppression, the simulated cell reached steady state with pacemaker period of 594 ms. Pacemaking current is carried by the Na+-Ca2+ exchanger, INaCa, which depends on the intracellular calcium concentration [Ca2+]i. This [Ca2+ ]i dependence suggests responsiveness (increase in rate) to ?-adrenergic stimulation (?AS), as observed experimentally. Simulations of ?AS demonstrate such responsiveness, which depends on INaCa expression. However, a simultaneous ?AS-mediated increase in the slow delayed rectifier, IKs, limits ?AS sensitivity.

Silva, Jonathan; Rudy, Yoram

2007-01-01

339

Remote monitoring of cardiac implantable devices in the Asia-Pacific.  

PubMed

Remote monitoring of pacemakers and implantable cardioverter defibrillators (ICDs) has emerged as a tool to replace regular follow-up of such devices, and to detect hardware failure, arrhythmias, and heart failure decompensation. The Asia-Pacific region is a geographically diverse area, with widely different cardiac device implant rates and expertise. However, common to all countries, distance and logistic for patients to reach an expert monitoring centre for routine follow up are significant, and in some countries, this will likely be replaced by remote monitoring. Unscheduled visits such as for the treatment of atrial fibrillation and ICD shocks will be expedited. There has been an increase in both pacemaker and ICD implant rates in Asia-Pacific, due to an ageing population and improvement in economic condition. Among the countries, Australia and Japan are the major users of remote monitoring. According to the statistics of the suppliers, in Australia, up to 15% of pacemakers, 40% ICD, and 30% cardiac resynchronization therapy (CRT)/cardiac resynchronization therapy defibrillator (CTRD) are remotely monitored. The corresponding numbers for Japan are 5, 50, and 50% respectively. The monitoring personnel include nurses, technicians, and doctors, either from local centre or from device companies. Cost, lack of reimbursement, and logistic support are major issues in widespread application of remote monitoring technology. In conclusion, remote monitoring is increasing in Asia-Pacific region despite the increase in cost. Implantable cardioverter defibrillators and CRT/CRTDs are more likely than pacemakers to be enabled with remote monitoring. PMID:23737235

Lau, Chu-Pak; Zhang, Shu

2013-06-01

340

Clinical testing of a new pacemaker function to monitor ventricular capture.  

PubMed

Automatic beat-by-beat capture functions are designed to minimize the pacing energy delivered, while maintaining the highest safety by delivering an immediate back-up stimulus in case of loss of capture. The objective of this study was to estimate the lowering of ventricular pacing amplitude allowed by such a function, compared to amplitudes usually set manually in routine practice. An automatic ventricular pacing threshold test is launched every 6 hours to measure the automatic capture threshold (AT). From AT the function calculates: (1) the"capture amplitude"(V(c)) = AT + 0.5 V at a minimum output of 1 V and (2) the"safety amplitude" (V(s)) = twice AT at a minimum output of 2.5 V. The function preferentially uses V(c) and verifies capture after each paced beat. In case of loss of capture, a back-up spike is delivered and V(s) is implemented until the next threshold measurement. We estimated the ventricular amplitude delivered by the pacemaker from data stored in the pacemaker memory. We compared these values with the pacing amplitude typically programmed manually (MPA) by physicians at twice AT and a minimum of 2.5 V. Data from 57 recipients of Talent 3 DR pacemakers were analyzed. Complete data sets were available in 25 patients at 1 day, 28 at 1 month, and 39 between 1 day and 1 month. No loss of capture or ventricular pause was observed on 53 ambulatory electrocardiograms (ECG); and pulse amplitude automatically delivered by the device was significantly lower than the MPA at each of the three time points analyzed. This new beat-by-beat capture function allows a significant lowering of the pacing amplitude compared to manual settings, while preserving a 100% safety. PMID:15683521

Alonso, Christine; Savouré, Arnaud; Jauvert, Gael; Casset, Cyrille; Ranaivoson, Hanta; Cazeau, Serge; Anselme, Frédéric

2005-01-01

341

A randomized trial of long-term remote monitoring of pacemaker recipients (The COMPAS trial)  

PubMed Central

Aims Professional practice guidelines recommend that pacemaker recipients be followed regularly. However, the majority of scheduled ambulatory visits is unproductive and imposes a heavy burden on the health-care system. Methods and results The COMPAS randomized, multicentre, non-inferiority trial examined the safety of long-term remote monitoring of pacemakers. Between December 2005 and January 2008, 538 patients were randomly assigned to remote monitoring follow-up (active group) vs. standard care (control group). The primary objective was to confirm that the proportion of patients who experienced at least one major adverse event (MAE), including all-cause death and hospitalizations for device-related or cardiovascular adverse events, was not >7% higher in the active than in the control group. MAE-free survivals and quality of life were compared in both groups. The characteristics of the study groups were similar. Over a follow-up of 18.3 months, 17.3% of patients in the active and 19.1% in the control group experienced at least one MAE (P < 0.01 for non-inferiority). Hospitalizations for atrial arrhythmias (6 vs. 18) and strokes (2 vs. 8) were fewer (P < 0.05), and the number of interim ambulatory visits was 56% lower (P < 0.001) in the active than the control group. Changes in pacemaker programming or drug regimens were made in 62% of visits in the active vs. 29% in the control group (P < 0.001). Quality of life remained unchanged in both groups. Conclusion Remote monitoring was a safe alternative to conventional care and significantly lowered the number of ambulatory visits during long-term follow-up of permanently paced patients. ClinicalTrials.gov identifier: NCT00989326.

Mabo, Philippe; Victor, Frederic; Bazin, Patrick; Ahres, Said; Babuty, Dominique; Da Costa, Antoine; Binet, Didier; Daubert, Jean-Claude

2012-01-01

342

Experimental evidence of a chaotic region in a neural pacemaker  

NASA Astrophysics Data System (ADS)

In this Letter, we report the finding of period-adding scenarios with chaos in firing patterns, observed in biological experiments on a neural pacemaker, with fixed extra-cellular potassium concentration at different levels and taken extra-cellular calcium concentration as the bifurcation parameter. The experimental bifurcations in the two-dimensional parameter space demonstrate the existence of a chaotic region interwoven with the periodic region thereby forming a period-adding sequence with chaos. The behavior of the pacemaker in this region is qualitatively similar to that of the Hindmarsh-Rose neuron model in a well-known comb-shaped chaotic region in two-dimensional parameter spaces.

Gu, Hua-Guang; Jia, Bing; Chen, Guan-Rong

2013-03-01

343

Out-of-body experience and auditory and visual hallucinations in a patient with cardiogenic syncope: Crucial role of cardiac event recorder in establishing the diagnosis.  

PubMed

Out-of-body experience (OBE) and visual and auditory hallucinations can occur in a variety of medical conditions. We describe a 48-year-old male patient who experienced several paroxysmal events with different combinations of the aforementioned symptoms that could finally be attributed to cardiogenic syncope after subcutaneous implantation of an event recorder and that ceased after implantation of a cardiac pacemaker. Hallucinations and OBE are well-known phenomena in syncope. The special purpose of this report is to highlight the crucial role of implantation of the event recorder in establishing the diagnosis and the additional support of the diagnosis by the cessation after implanting the cardiac pacemaker. PMID:19268716

Brandt, Christian; Kramme, Corinna; Storm, Hermann; Pohlmann-Eden, Bernd

2009-06-01

344

Reprogramming of implanted pacemaker following external defibrillation.  

PubMed

This report describes reprogramming of a pulse generator consequent to cardiac defibrillation. Analysis of the explanted pulse generator revealed normal function. We tested the electrical properties of several defibrillators and our studies suggest that erratic electrostatic discharges at the time of paddle application before defibrillation may create a signal sequence capable of reprogramming the particular pulse generator by activating either the reed switch or internal electronics. PMID:95645

Barold, S S; Ong, L S; Scovil, J; Heinle, R A; Wright, T

1978-10-01

345

Atrial electromechanical sequence in normal subjects and patients with DDD pacemakers.  

PubMed Central

OBJECTIVE--To assess the effect of right atrial appendage pacing on atrial electromechanical interrelations in patients with DDD pacemakers. DESIGN--Prospective study by M mode echocardiogram, Doppler echocardiogram, and apexcardiogram, along with electrocardiogram and phonocardiogram. SETTING--Tertiary cardiac referral centre. PATIENTS--20 patients with DDD pacemakers and 20 age matched normal controls. RESULTS--Age, RR interval, atrial size, left ventricular size, and fractional shortening were similar in the two groups. Atrial electromechanical delay (the time from the onset of P wave or atrial pacing spike on ECG to the onset of atrial contraction on M mode echogram) was 68 (SD 7) ms at the lateral site of right atrium, 82 (9) ms at the central fibrous body, 93 (11) ms at the lateral site of left atrium in normals. In patients with DDD pacing, however, this delay increased to 85 (22) ms, 117 (23) ms, and 138 (25) ms respectively (all P < 0.01). Interatrial mechanical delay (the time from the onset of right atrial motion to the onset of the left) increased from 25 (6) ms in normal controls to 53 (18) ms in patients (P < 0.01). Intra-atrial mechanical dispersion (the time from the earliest to the latest onset of regional atrial motion around the atrioventricular ring) in the right atrium increased from 6 (2) ms in normals to 19 (2) ms in patients (P < 0.01), but it remained unchanged in the left atrium (6 (2) ms in normal controls v 7 (2) ms in patients, P > 0.05). Peak atrial shortening rate was not different between the two groups. Differences of atrial electromechanical activity between the two groups were also reflected on Doppler echocardiogram and apexcardiogram. CONCLUSIONS--Right atrial appendage pacing disturbs the normal coordinate sequence of right atrial mechanical activity and leads to a striking and variable increase in intra-atrial conduction time as well as in interatrial conduction time. Left atrial contraction remains synchronous although the timing of the start of its contraction was delayed. These values can be determined in individual patients to allow optimal setting of DDD pacemakers.

Wang, K.; Xiao, H. B.; Fujimoto, S.; Gibson, D. G.

1995-01-01

346

Inappropriate rate response in a VVI-R pacemaker.  

PubMed

The search for a pacemaker that accurately and easily mimics normal physiology is a continuing effort. Present pacing developments include AV synchrony and rate adaptiveness. The usefulness and clinical value of some of the new pacing systems remain unclear. Although the hemodynamic advantages of rate responsive pacing over classical ventricular pacing are well established (Kristensson et al., 1985), an ideal sensor for physiological demands has not been established. We report a case of apparently unequivocal increase in heart rate during upper limb movements in a patient with a VVI-R pacemaker using minute ventilation as a sensor. Inappropriate heart rate acceleration may result from changes in transthoracic impedance due to upper limb exercise and it does not necessarily represent sensor malfunction. Although this complication is well-known in VVI-R pacemakers using respiratory rate or minute ventilation as sensor (Santomauro et al., 1992), one must remain aware of this sensor-related problem. In this particular patient the problem could be solved by implanting the pacemaker can more medially. PMID:9124025

Vanderheyden, M; Timmermans, W; Goethals, M

1996-01-01

347

[Telemedicine in pacemaker therapy and follow-up].  

PubMed

Present-day remote systems for cardiovascular implantable electronic devices (CIEDs) provide, in contrast to previous solutions, a broad range of data about the patient and the implanted device ("remote control"). Telemedicine includes remote monitoring as well as remote follow-up: Remote monitoring is the continual interrogation of the device to detect patient- or device-related adverse events earlier than with standard follow-up visits. Remote follow-up aims to replace scheduled and unscheduled face-to-face follow-up visits due to the interrogation of the automatic pacemaker functions. Currently available remote systems, such as Home Monitoring, CareLink, Merlin.net, and Latitude, have in common that they interrogate the device, send these data to a server, and provide the data to the physician on a secured web site. Automatic wireless interrogation of the device is the preferred solution; however, the devices must have been equipped with a micro-antenna, which is usually restricted to more recent pacemaker models. Knowledge about remote control in pacemaker patients is limited, because most remote applications were evaluated in ICD and CRT patients. While the most frequently reported clinical event in pacemaker patients is atrial fibrillation, the impact in routine clinical follow-up still has to be evaluated in detail. Device-related adverse events are rare. Large, long-term, randomized trials are comparing remote and conventional approaches with the aim of demonstrating the benefits of telemedicine in this patient group. PMID:19937330

Schuchert, A

2009-12-01

348

Pacemaker Related Infective Endocarditis from Staphylococcus Lugdunensis: A Case Report  

PubMed Central

Staphylococcus lugdunensis is a common skin flora not typically associated with infection. There are, however, several cases reported in the literature of Staphylococcus lugdunensis as a causative bacterium of various infections. This paper reports an additional case of pacemaker associated endocarditis with Staphylococcus lugdunensis as the causative bacterium.

Ward, Michael; Boehm, Kevin M.

2013-01-01

349

Design of the Pacemaker REmote Follow-up Evaluation and Review (PREFER) trial to assess the clinical value of the remote pacemaker interrogation in the management of pacemaker patients  

Microsoft Academic Search

BACKGROUND: Although pacemakers are primarily used for the treatment of bradycardia, diagnostic data available in current pacemakers allow them to be also used as sophisticated, continuous monitoring devices. Easy access to these stored data may assist clinicians in making diagnostic and therapeutic decisions sooner, thus avoiding potential long-term sequelae due to untreated clinical disorders. Internet-based remote device interrogation systems provide

Jane Chen; Bruce L Wilkoff; Wassim Choucair; Todd J Cohen; George H Crossley; W Ben Johnson; Luc R Mongeon; Gerald A Serwer; Lou Sherfesee

2008-01-01

350

Stimulating Cardiac Muscle by Light: Cardiac Optogenetics by Cell Delivery  

PubMed Central

Background After the recent cloning of light-sensitive ion channels and their expression in mammalian cells, a new field, optogenetics, emerged in neuroscience, allowing for precise perturbations of neural circuits by light. However, functionality of optogenetic tools has not been fully explored outside neuroscience; and a non-viral, non-embryogenesis based strategy for optogenetics has not been shown before. Methods and Results We demonstrate the utility of optogenetics to cardiac muscle by a tandem cell unit (TCU) strategy, where non-excitable cells carry exogenous light-sensitive ion channels, and when electrically coupled to cardiomyocytes, produce optically-excitable heart tissue. A stable channelrhodopsin2 (ChR2) expressing cell line was developed, characterized and used as a cell delivery system. The TCU strategy was validated in vitro in cell pairs with adult canine myocytes (for a wide range of coupling strengths) and in cardiac syncytium with neonatal rat cardiomyocytes. For the first time, we combined optical excitation and optical imaging to capture light-triggered muscle contractions and high-resolution propagation maps of light-triggered electrical waves, found to be quantitatively indistinguishable from electrically-triggered waves. Conclusions Our results demonstrate feasibility to control excitation and contraction in cardiac muscle by light using the TCU approach. Optical pacing in this case uses less energy, offers superior spatiotemporal control, remote access and can serve not only as an elegant tool in arrhythmia research, but may form the basis for a new generation of light-driven cardiac pacemakers and muscle actuators. The TCU strategy is extendable to (non-viral) stem cell therapy and is directly relevant to in vivo applications.

Jia, Zhiheng; Valiunas, Virginijus; Lu, Zongju; Bien, Harold; Liu, Huilin; Wang, Hong-Zhang; Rosati, Barbara; Brink, Peter R.; Cohen, Ira S.; Entcheva, Emilia

2011-01-01

351

Health Technology Assessment Reports, 1987. Number 6. Cardiac Rehabilitation Services.  

National Technical Information Service (NTIS)

Cardiac rehabilitation services are comprehensive, long-term programs involving medical evaluation, prescribed exercise, cardiac risk factor modification, education, and counseling. The programs are designed to limit the physiologic and psychological effe...

E. Feigenbaum E. Carter

1988-01-01

352

Absent right and persistent left superior vena cava: troubleshooting during a challenging pacemaker implant: a case report  

PubMed Central

Background Venous anomalies of the thorax can occur in isolation or in association with complex congenital heart disease. The incidence of an absent right superior vena cava in the setting of a persistent left superior vena cava is very rare in the general population with only a dozen cases documented in the medical literature. Such venous anomalies can make for very challenging electronic cardiac device implantation. We report our challenging dual chamber pacemaker implant in a patient with such complex anatomy and focus on our implantation technique that helped achieve adequate lead positioning. Case presentation A 73-year-old Caucasian female with degenerative complete heart block presented for dual chamber permanent pacemaker implant. Lead implantation was very challenging due to abnormal and rare vena cava anatomy; a persistent left superior vena cava drained directly into the coronary sinus and the right brachiocephalic vein drained directly into the left persistent superior vena cava as the patient had an absent right superior vena cava . Adequate right ventricular lead positioning was achieved following numerous lead-stylet manipulations and careful looping in the atria to redirect its trajectory to the ventricular apex. Conclusion Abnormal superior vena cava development is uncommon and can lead to technical challenges when venous access is required during various interventional procedures. Pre-operative imaging can help identify such challenging anatomy allowing appropriate operative planning; careful patient selection is warranted for venography given the risk of contrast nephrotoxicity.

2014-01-01

353

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

PubMed Central

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

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

1997-01-01

354

Individual and concomitant effects of cardioprotective programs on cardiac apelinergic system and oxidative state in L-NAME-induced hypertension.  

PubMed

The effect of aerobic training and Ferula gummosa supplementation (90 mg/kg) on apelinergic system and markers of cardiac stress in hypertensive rats were studied. Chronically administered l-NAME resulted in an increased level of angiotensin-converting enzyme (ACE), malondialdehyde (MDA), and high-sensitive C-reactive protein (hs-CRP), and also reduced the levels of apelin, apelin and its receptor (APJ), and nitric oxide (NO) and the total antioxidant capacity (TAC), when compared with the control group. The combination of aerobic exercise and Ferula gummosa decreased MDA and hs-CRP and significantly increased cardiac apelinergic system, NO, and TAC, when compared with the control and the l-NAME groups. A rationale for an inhibitory role and a cardioprotective effect of aerobic exercise training in the attenuation of hypertension-induced cardiotoxicity was developed. PMID:22578103

Mahmoody, Seeyed Ali Akbar; Gharakhanlou, Reza; Roshan, Valiollah Dabidi; Hedayati, Mehdi

2013-01-01

355

Atrioventricular node ablation and pacemaker implantation for recurrent syncope in a patient with postural tachycardia syndrome (POTS).  

PubMed

Ablate and pace for POTS. A 42-year-old woman with postural tachycardia syndrome (POTS) was admitted to our hospital with severe palpitations, light-headedness, and syncope. Several drugs had been administered previously, but all had been discontinued due to intolerable adverse effects or limited efficacy. One of the drugs, the I(f) current inhibitor ivabradine, effectively slowed the patient's heart rate and relieved the symptoms, but was discontinued due to allergy. After unsuccessful sinus node ablation, atrioventricular node ablation and dual chamber pacemaker implantation was performed, which dramatically improved her symptoms and eliminated syncope. Atrioventricular node ablation could modify the cardiac autonomic balance and thereby suppressed the excessive orthostatic sympathetic activity. PMID:21539639

Nakatani, Yosuke; Mizumaki, Koichi; Nishida, Kunihiro; Inoue, Hiroshi

2011-11-01

356

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

PubMed

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

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

357

About Cardiac Arrest  

MedlinePLUS

... High Blood Pressure Tools & Resources Stroke More About Cardiac Arrest Updated:Nov 25,2013 What is cardiac arrest? ... content was last reviewed on 02/26/2013. Cardiac Arrest • Home • About Cardiac Arrest • Warning Signs for Cardiac ...

358

Detection of Atrial Fibrillation by Permanent Pacemakers: Observations from the STOP AF Trial  

Microsoft Academic Search

Pacemaker telemetry is increasingly being used to infer the presence or absence of arrhythmias in clinical practice. To evaluate the reliability of these data in patients with sick-sinus syndrome, a sub-study of eighteen consecutive patients in the Systematic Trial of Pacing to prevent Atrial Fibrillation (STOP AF) implanted with dual-chamber pacemakers had simultaneous 24-hour Holter recordings and pacemaker telemetry down-loaded.

C. J. Plummer; J. M. McComb

2003-01-01

359

[Chylothorax as a late complication of pacemaker endocarditis].  

PubMed

The mortality observed in pacemaker endocarditis may be high when all the components of the device are not withdrawn. Few studies have reported the posterior morbidity once the acute disease is resolved. Herein we present a patient who developed superior vena cava thrombosis, obstruction of thoracic duct and chylothorax after the initial episode of endocarditis. The evolution of the patient illustrates the late complications of isolated antibiotic treatment of pacemaker endocarditis, the poor results obtained with temporal oral anticoagulation in the management of superior vena cava thrombosis in the presence of retained intravascular foreign material, the excellent, prolonged initial response of chylothorax to conservative measures with anticoagulation and diet, relapse of chylothorax related to the increase in arterial pulmonary pressure, the absence of response at this time to the dietary measures and the successful treatment with video-assisted thoracic surgery to treat chylothorax without the morbidity of the large surgical procedures. PMID:11181315

Cepeda, C S; Lahulla, F; de las Heras, E P; San Martín, J V; Santos, J H; Melcón, G G

2001-02-01

360

Persistently Active, Pacemaker-Like Neurons in Neocortex  

PubMed Central

The neocortex is spontaneously active, however, the origin of this self-generated, patterned activity remains unknown. To detect potential “pacemaker cells,” we use calcium imaging to directly identify neurons that discharge action potentials in the absence of synaptic transmissionin slices from juvenile mouse visual cortex. We characterize 60 of these neurons electrophysiologically and morphologically, finding that they belong to two classes of cells: one class composed of pyramidal neurons with a thin apical dendritic tree and a second class composed of ascending axon interneurons (Martinotti cells) located in layer 5. In both types of neurons, persistent sodium currents are necessary for the generation of the spontaneous activity. Our data demonstrate that subtypes of neocortical neurons have intrinsic mechanisms to generate persistent activity. Like in central pattern generators (CPGs), these neurons may act as “pacemakers” to initiate or pattern spontaneous activity in the neocortex.

Le Bon-Jego, Morgane; Yuste, Rafael

2007-01-01

361

Multiple pulse generator malfunctions with a dual chamber pacemaker.  

PubMed

The aim of this study was to evaluate the dual chamber uni/bipolarpacemaker Minidual 50, manufactured by Sorin Biomedica. Between 1995 and 1998, 66 Minidual 50 models were implanted at the Heart Institute. During the follow-up period of 33 +/- 12.8 months (range 0-50 months), total function loss in seven (10.6%) units and false threshold measurement of sensing and pacing in three (4.5%) patients were observed. Average time from implantation to malfunction was 37 months (range 28-42). Malfunction was unrelated to battery status and could not be predicted by any measures obtained during the pacemaker follow-up period. Kaplan Meyer survival curve predicted a 70% 4-year malfunction-free survival of that pacemaker model. Given this high rate of total malfunction and the unpredictable nature of its occurrence, the authors recommend the replacement of all remaining Minidual 50 units at risk, at least in dependent patients. PMID:12137346

Lipchenca, Igor; Barlev, David; Luria, David; Granit, Chava; Rotshtein, Zeev; Eldar, Michael; Glikson, Michael

2002-06-01

362

Persistent left superior vena cava and pacemaker implantation.  

PubMed

Our study group read with interest the paper from Vijayvergiya et al describing the implantation of an implantable cardioverter-defibrillator lead in the presence of the persistence of the left superior vena cava. The issue of the identification a persistent left superior vena cava is of paramount importance in interventional cardiology, being the most common venous anomaly of the thoracic distribution, and because it may create some problem to any physician while performing a pacemaker lead implantation. In our letter we underscore the specific issues related to pacemaker implantation while encountering a persistent left superior vena cava (and maybe the absence of the right vena cava) and the workup that should be performed to obtain the preoperative diagnosis of the venous anomaly. More specifically, we consider avoiding any kind of defibrillator lead implantation through the coronary sinus for safety issues, and underscore the straightforward transthoracic ultrasound approach to identify the left superior vena cava. PMID:24109503

Pontillo, Daniele; Patruno, Nicolino

2013-09-26

363

A Dutch case of a takotsubo cardiomyopathy after pacemaker implantation  

PubMed Central

An 83-year-old female patient with symptomatic atrial fibrillation was referred to the Department of Cardiology for a scheduled electrocardioversion. Because of a junctional escape rhythm after the electrocardioversion she received a DDD pacemaker which was complicated by dyspnoea and ST-segment elevations in the inferior and precordial leads. Because of suspicion of an acute myocardial infarction she was transferred to a PCI centre. The coronary angiogram showed no abnormalities. In the initial phase, an echocardiogram was performed. The echocardiogram showed apical akinesis and a reduced left ventricular function. During follow-up left ventricular function improved and was completely normal nine weeks after the event. The clinical picture was interpreted as a takotsubo cardiomyopathy after a pacemaker implantation. (Neth Heart J 2009;17:487-90.)

Kohnen, R.F.; Baur, L.H.B.

2009-01-01

364

Telephone monitoring of patients with pacemakers in the west of Scotland.  

PubMed Central

A regional telephone pacemaker follow-up service has been established in the west of Scotland. Medical care is provided by clinics at district general hospitals in Ayrshire, and the pacemaker signals are transmitted by telephone from these clinics to a pacemaker centre in Glasgow. The success of the pilot project in Ayrshire will allow expansion of the service to include hospitals in other areas of the west of Scotland. The scheme is carefully monitored to ensure that patients with pacemakers receive adequate attention with a minimum of inconvenience. Images FIG 2

Shaw, G B; Evans, A L; Brewster, G M; Groden, B M; Murdoch, W R

1981-01-01

365

A Functional analysis of circadian pacemakers in nocturnal rodents  

Microsoft Academic Search

Summary 1Phase response curves for 15' bright light pulses of four species of nocturnal rodents are described. All show delay phase shifts early in the subjective night, advance shifts in the late subjective night, and relative insensitivity during the subjective day.2The broad scatter in measured phase-shifts is largely due to error of measurement: the response of the pacemakers to light

Serge Daan; Colin S. Pittendrigh

1976-01-01

366

Regulation of pacemaker frequency in the murine gastric antrum  

PubMed Central

PGE2 has been linked to the production of gastric arrhythmias such as tachygastria. The interstitial cells of Cajal (ICC) generate electrical rhythmicity in gastrointestinal muscles, and may therefore be a target for PGE2 in gastric muscles. We cultured ICC from the murine gastric antrum, verified that cells were Kit immunoreactive, and measured spontaneous slow waves. These events were caused by spontaneous inward (pacemaker) currents that were not blocked by nifedipine. Forskolin and 8-bromoadenosine 3?:5?-cyclic monophosphate (8-Br-cAMP) reduced the frequency of pacemaker currents in ICC and of slow waves in intact antral muscles. The effects of forskolin and 8-Br-cAMP were not blocked by inhibitors of protein kinase A, suggesting that cAMP has direct effects on pacemaker activity. PGE2 mimicked the effects of forskolin and 8-Br-cAMP on ICC, but increased slow-wave frequency in intact muscles. Therefore, the chronotropic effects of specific prostaglandin EP receptor agonists were examined. Butaprost and ONO-AE1-329, EP2 and EP4 receptor agonists, mimicked the effects of forskolin and 8-Br-cAMP on ICC and intact muscles. Sulprostone (EP3>EP1 agonist), GR63799, and ONO-AE-248 (EP3 agonists) enhanced the frequencies of pacemaker currents in ICC and slow waves in intact muscles. The effects of sulprostone were not blocked by SC-19220, an EP1 receptor antagonist. These observations suggest that the positive chronotropic effects of PGE2 in intact muscles are mediated by EP3 receptor stimulation. The effects of PGE2 in intact muscles may be dependent upon the relative expression of EP receptors and/or proximity of receptors to sources of PGE2.

Kim, Tae Wan; Beckett, Elizabeth A H; Hanna, Rhonda; Koh, Sang Don; Ordog, Tamas; Ward, Sean M; Sanders, Kenton M

2002-01-01

367

BATTERIES WITH RbAg4I5 FOR PACEMAKER  

Microsoft Academic Search

A wide diversity of batteries is utilized such as i mplanted medical devices (pacemaker) and external devices for monitoring of bodily functions. In this paper are presented the main characteristics of Ag\\/RbAg 4I5\\/RbI 3 cell. The electrochemical behavior of the batterie s with RbAg 4I5 solid electrolyte was studied by performance curve s in two discharge regimes.

C. S. BOLLA; ELEONORA MARIA RUS; DELIA MARIA CONSTANTIN

368

Multicenter clinical evaluation of a new SSIR pacemaker.  

PubMed

A multicenter clinical evaluation of Sorin Swing 100, a new SSIR pacemaker with a gravimetric sensor, was performed by seven different centers enrolling a total of 89 patients, 56 men and 33 women, mean age 73.1 years, for pacemaker implantation (73 patients) or pacemaker replacement (16 patients). Pacing mode was VVIR in 73 patients and AAIR in 16. The behavior of pacing rate was evaluated 3 months after the implant by performing a 24-hour Holter monitor, an exercise stress test, and tests for the assessment of mechanical external interference (MEI). A physiological behavior of the paced rate was always observed during Holter monitoring. In 52 completely paced patients mean diurnal, nocturnal, and maximal heart rate were, respectively, 74.9 +/- 5.7 ppm, 58.1 +/- 5.8 ppm, and 113.4 +/- 12.7 ppm; a paced rate exceeding 100 ppm was reached on the average 5.6 times/Holter monitor. In all but two patients the sleep rate (55 ppm) was reached during the night or long resting time. During exercise stress test a direct correlation between the increase in pacing rate and the increase in workload was observed; the mean maximal heart rate reached in 49 completely paced patients was, respectively, 102.8 +/- 9 ppm in 17 patients who accomplished stage 1, 116.2 +/- 13.6 ppm in 28 patients who accomplished stage 2, and 133 +/- 6.7 ppm in 10 patients who accomplished stage 3 of the Bruce protocol. MEI testing never increased the pacing rate over the noise rate (10 ppm over the basic rate). In only seven patients the results obtained suggested to change the nominal set up of the pacemaker.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1279550

Bongiorni, M G; Soldati, E; Arena, G; de Simone, L; Capucci, A; Galli, R; Parlapiano, M; Cazzin, R; Moracchini, P; Leonardi, C

1992-11-01

369

Endovascular extraction techniques for pacemaker and ICD lead extraction  

PubMed Central

In the last few years, comprehensive endovascular techniques have been developed to extract chronically implanted pacemaker and defibrillator leads. It is important that referring physician have knowledge of the advantages and limitations of the different techniques. In this paper we discuss the techniques and results of the currently used endovascular extraction techniques. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7

Bracke, F.A.; Meijer, A.; van Gelder, B.

2001-01-01

370

Permanent pacemaker-associated actinomycetemcomitans endocarditis: A case report.  

PubMed

Aggregatibacter actinomycetemcomitans is a Gram-negative bacillus, member of the HACEK group of bacteria, and it is a very rare cause of endocarditis. It is also an extremely rare cause of device-associated infection of the heart. We describe the case of a 25 year-old man who presented with pacemaker-associated endocarditis due to Aggregatibacter actinomycetemcomitans and also discuss the implications and treatment of this organism. PMID:24432293

Li, Zhenhong; Madeo, Jennifer; Ahmed, Shadab; Vidal, Alex; Makaryus, Amgad; Mejia, Jose; Yasmin, Tabassum

2013-09-01

371

Cardiac rhabdomyosarcoma.  

PubMed

Cardiac sarcoma is a very rare neoplasm and is difficult to diagnose. The case of a 51-year-old man with a left atrial tumour, locally recurrent three months after its surgical removal, is presented. Computed tomography showed metastatic spread to the lung parenchyma. On revised histology, the mass extirpated was a sarcoma. Because of the metastatic spread, further therapy was symptomatic only; the patient died 15 months after the first manifestation of his problems. Immunohistochemical staining confirmed cardiac rhabdomyosarcoma with metastatic spread to the lungs. Difficulty in diagnosing and treating cardiac tumours is discussed. PMID:20428274

Chlumský, J; Holá, D; Hlavácek, K; Michal, M; Svec, A; Spatenka, J; Dusek, J

2001-01-01

372

Pacemaker implantation in a patient with brugada and sick sinus syndrome  

PubMed Central

Brugada syndrome (BrS) is a rare and inherited primary arrhythmic syndrome characterized by ST-segment elevations in the right precordial leads (V1-V3) with an increased risk of sudden cardiac death (SCD). Arrhythmias in BrS are often nocturne, and brady-arrhythmias are often seen in patients with loss-of-function mutations in SCN5A. In this case-report we present a 75-year old woman referred to our outpatient clinic for inherited cardiac diseases for a familial clinical work-up. Since childhood she had suffered from dizziness, absence seizures, and countless Syncope’s. In 2004 sick sinus syndrome was suspected and she was treated with implantation of a pacemaker (PM) at another institution. An inherited cardiac disease was one day suddenly suspected, as the patient had a 61-year old brother who was diagnosed with symptomatic BrS, and treated with an implantable cardioverter defibrillator (ICD) after aborted SCD. A mutation screening revealed a SCN5A [S231CfsX251 (c.692-693delCA)] loss-of-function mutation not previously reported, and as a part of the cascade screening in relatives she was therefore referred to our clinic. In the 7 year period after PM implantation she had experienced no cardiac symptoms, although her electrocardiogram changes now were consistent with a BrS type 1 pattern. A genetic test confirmed that she had the same mutation in SCN5A as her brother. In this case-report we present a loss-of function mutation in SCN5A not previously associated with BrS nor presented in healthy controls. Sinus node dysfunction has previously been documented in patients with symptomatic BrS, which suggests it is not a rare concomitant. The only accepted treatment of BrS is today implantation of an ICD. In the future studies should evaluate if PM in some cases of symptomatic BrS can be used instead of ICDs in patients with a loss-of-function SCN5A mutations

Risgaard, Bjarke; Bundgaard, Henning; Jabbari, Reza; Hauns?, Stig; Winkel, Bo Gregers; Tfelt-Hansen, Jacob

2013-01-01

373

Pacemaker implantation in a patient with brugada and sick sinus syndrome.  

PubMed

Brugada syndrome (BrS) is a rare and inherited primary arrhythmic syndrome characterized by ST-segment elevations in the right precordial leads (V1-V3) with an increased risk of sudden cardiac death (SCD). Arrhythmias in BrS are often nocturne, and brady-arrhythmias are often seen in patients with loss-of-function mutations in SCN5A. In this case-report we present a 75-year old woman referred to our outpatient clinic for inherited cardiac diseases for a familial clinical work-up. Since childhood she had suffered from dizziness, absence seizures, and countless Syncope's. In 2004 sick sinus syndrome was suspected and she was treated with implantation of a pacemaker (PM) at another institution. An inherited cardiac disease was one day suddenly suspected, as the patient had a 61-year old brother who was diagnosed with symptomatic BrS, and treated with an implantable cardioverter defibrillator (ICD) after aborted SCD. A mutation screening revealed a SCN5A [S231CfsX251 (c.692-693delCA)] loss-of-function mutation not previously reported, and as a part of the cascade screening in relatives she was therefore referred to our clinic. In the 7 year period after PM implantation she had experienced no cardiac symptoms, although her electrocardiogram changes now were consistent with a BrS type 1 pattern. A genetic test confirmed that she had the same mutation in SCN5A as her brother. In this case-report we present a loss-of function mutation in SCN5A not previously associated with BrS nor presented in healthy controls. Sinus node dysfunction has previously been documented in patients with symptomatic BrS, which suggests it is not a rare concomitant. The only accepted treatment of BrS is today implantation of an ICD. In the future studies should evaluate if PM in some cases of symptomatic BrS can be used instead of ICDs in patients with a loss-of-function SCN5A mutations. PMID:23538678

Risgaard, Bjarke; Bundgaard, Henning; Jabbari, Reza; Haunsø, Stig; Winkel, Bo Gregers; Tfelt-Hansen, Jacob

2013-03-26

374

Direct inhibition of the pacemaker (If) current in rabbit sinoatrial node cells by genistein  

PubMed Central

Genistein is a tyrosine kinase inhibitor which interferes with the activity of several ionic channels either by altering modulatory phosphorylating processes or by direct binding. In whole-cell conditions, genistein induces a partial inhibition of the pacemaker (If) current recorded in cardiac sinoatrial and ventricular myocytes. We investigated the mechanism of action of genistein (50??M) on the If current in whole-cell, cell-attached, and inside-out configurations, and the measured fractional inhibitions were similar: 26.6, 27.2, and 33.6%, respectively. When ATP was removed from the whole-cell pipette solution no differences were revealed in the effect of the drug when compared to metabolically active cells. Genistein fully maintained its blocking ability even when herbimycin, a tyrosine kinase inhibitor, was added to the whole-cell ATP-free pipette solution. Genistein-induced block was independent of the gating state of the channel and did not display voltage or current dependence; this independence distinguishes genistein from all other f-channel blockers. When inside-out experiments were performed to test for a direct interaction with the channel, genistein, superfused on the intracellular side of the membrane, decreased the maximal If conductance, and slightly shifted the current–activation curve to the left. Furthermore, the effect of genistein was independent of cAMP modulation. We conclude that, in addition to its tyrosine kinase-inhibitory properties, genistein also blocks If by directly interacting with the channel, and thus cannot be considered a valuable pharmacological tool to investigate phosphorylation-dependent modulatory pathways of the If current and of cardiac rhythm.

Altomare, Claudia; Tognati, Agnese; Bescond, Jocelyn; Ferroni, Arnaldo; Baruscotti, Mirko

2005-01-01

375

Evaluation of pacemaker telemetry as a diagnostic feature for detecting atrial tachyarrhythmias in patients with sick sinus syndrome  

Microsoft Academic Search

AimThe aim of the present study was to validate pacemaker telemetry as a diagnostic feature for detecting atrial tachyarrhythmias (AT) during pacemaker treatment in patients with sick sinus syndrome (SSS).

Lene Kristensen; Jens Cosedis Nielsen; Peter Thomas Mortensen; Anders Kirstein Pedersen; Henning Rud Andersen

2004-01-01

376

Cardiac Ochronosis  

PubMed Central

We report the case of 67-year-old woman who underwent aortic valve replacement and mitral valve repair due to ochronotic valvular disease (alkaptonuria), which was diagnosed incidentally during cardiac surgery.

Erek, Ersin; Casselman, Filip P.A.; Vanermen, Hugo

2004-01-01

377

Cardiac catheterization  

MedlinePLUS

... amyloidosis Causes of congestive heart failure or cardiomyopathy Coronary artery disease Heart defects that are present at birth ( ... include: Cardiac tamponade Heart attack Injury to a coronary artery Irregular heartbeat Low blood pressure Reaction to the ...

378

Cardiac MRI  

MedlinePLUS

... from the NHLBI on Twitter. What Is Cardiac MRI? Magnetic resonance imaging (MRI) is a safe, noninvasive test that creates detailed ... and no instruments are inserted into your body. MRI uses radio waves, magnets, and a computer to ...

379

Information technology implementing globalization on strategies for quality care provided to children submitted to cardiac surgery: International Quality Improvement Collaborative Program - IQIC.  

PubMed

Introduction: Congenital heart diseases are the world's most common major birth defect, affecting one in every 120 children. Ninety percent of these children are born in areas where appropriate medical care is inadequate or unavailable. Objective: To share knowledge and experience between an international center of excellence in pediatric cardiac surgery and a related program in Brazil. Methods: The strategy used by the program was based on long-term technological and educational support models used in that center, contributing to the creation and implementation of new programs. The Telemedicine platform was used for real-time monthly broadcast of themes. A chat software was used for interaction between participating members and the group from the center of excellence. Results: Professionals specialized in care provided to the mentioned population had the opportunity to share to the knowledge conveyed. Conclusion: It was possible to observe that the technological resources that implement the globalization of human knowledge were effective in the dissemination and improvement of the team regarding the care provided to children with congenital heart diseases. PMID:24896168

Sciarra, Adilia Maria Pires; Croti, Ulisses Alexandre; Batigalia, Fernando

2014-03-01

380

Cardiac Angiosarcoma  

PubMed Central

Despite cardiac metastases are found in about 20% of cancer deaths, the presence of primary cardiac tumors is rare. Most primary tumors are benign, and malignant tumors comprise about 15%. We report a 21-year-old man with fever, dyspnea, and hemoptysis that was diagnosed with angiosarcoma of the right atrium and pulmonary metastasis. Patient was submitted to surgical tumor resection without adjuvant therapy and died four months after diagnosis.

Cardoso, Monique Esteves; Canale, Leonardo Secchin; Ramos, Rosana Grandelle; Salvador Junior, Edson da Silva; Lachtermacher, Stephan

2011-01-01

381

A Model of Cardiac Electrical Activity Incorporating Ionic Pumps and Concentration Changes  

Microsoft Academic Search

Equations have been developed to describe cardiac action potentials and pacemaker activity. The model takes account of extensive developments in experimental work since the formulation of the M.N.T. (R. E. McAllister, D. Noble and R. W. Tsien, J. Physiol., Lond. 251, 1-59 (1975)) and B.R. (G. W. Beeler and H. Reuter, J. Physiol., Lond. 268, 177-210 (1977)) equations. The current

D. Difrancesco; D. Noble

1985-01-01

382

Effects of transient receptor potential channel blockers on pacemaker activity in interstitial cells of Cajal from mouse small intestine  

Microsoft Academic Search

The interstitial cells of Cajal (ICCs) are pacemakers in the gastrointestinal tract and transient receptor potential melastatin\\u000a type 7 (TRPM7) is a candidate for pacemaker channels. The effect of the 5-lipoxygenase (5-LOX) inhibitors NDGA, AA861, MK886\\u000a and zileuton on pacemaking activity of ICCs was examined using the whole cell patch clamp technique. NDGA and AA861 decreased\\u000a the amplitude of pacemaker

Byung Joo Kim; Joo Hyun Nam; Seon Jeong Kim

383

Pacemaker Primary Curriculum; Lesson Book Level B.  

ERIC Educational Resources Information Center

This lesson book, which is the second in a four-level program for young children with learning difficulties, describes the purpose of and equipment and procedures for teaching lessons in the following subjects areas on the primary grade level: arithmetic, reading, vocabulary, listening, planning, problem solving, social behavior, art, music, and…

Ross, Dorothea M.; Ross, Sheila A.

384

Pacemaker Primary Curriculum; Lesson Book Level D.  

ERIC Educational Resources Information Center

This lesson book, which is the last in a four-level program for young children with learning difficulties, describes the purpose of and equipment and procedures for teaching lessons in the following subject areas on the primary level: arithmetic, reading, vocabulary, spelling, printing, listening, planning and problem solving, social behavior,…

Ross, Dorothea M.; Ross, Sheila A.

385

Pacemaker Primary Curriculum; Lesson Book Level A.  

ERIC Educational Resources Information Center

This lesson book, which is the first in a four-level program for young children with learning difficulties, describes the purpose of and equipment and procedures for teaching lessons in the following subject areas on the kindergarten level: arithmetic concepts, number concepts, reading readiness, vocabulary, language, listening, social behavior,…

Ross, Dorothea M.; Ross, Sheila A.

386

Pacemaker Primary Curriculum; Lesson Book Level C.  

ERIC Educational Resources Information Center

This lesson book, which is the third in a four-level program for young children with learning difficulties, describes the purpose of and equipment and procedures for teaching lessons in the following subject areas on the primary grade level: arithmetic, reading, vocabulary, spelling, printing, listening, planning, problem solving, social behavior,…

Ross, Dorothea M.; Ross, Sheila A.

387

Searching for non-sense: identification of pacemaker non-sense and non-capture failures using machine learning techniques  

Microsoft Academic Search

Abnormal or unexpected function of pacemakers due to mechanical failure of the implantation, electrical failures of the battery and electrodes, or physiological failures to respond to the stimulus may cause harm to a patient. A novel Bayesian decision tree algorithm is proposed to detect two types of pacemaker failures, non-sense and non-capture, without a priori knowledge of pacemaker type, model,

M. R. B. Malinowski; R. J. Povinelli

2003-01-01

388

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

Microsoft Academic Search

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

J. E. R. STADDON; J. J. HIGA

1999-01-01

389

A rate-responsive pacemaker controlled by right ventricular blood temperature.  

PubMed

To demonstrate the capabilities of a rate-responsive pacemaker controlled by right ventricular blood temperature, a prototype pacemaker was developed and tested in dogs with complete atrioventricular (AV) block. Using a previously obtained data base of right ventricular blood temperature recorded both during rest and during treadmill exercise from dogs with either induced AV block or normal AV conduction, a control algorithm which identified periods of exercise was developed. This algorithm was implemented in a microprocessor-based, rate-responsive pacemaker which generates two pacing rates: a basal rate (86 bpm) during rest and a higher rate (113 bpm) during moderate exercise. With repeated trials of submaximal treadmill exercise (2.25, 3.0, 5.0 mph, 16% grade) the pacemaker correctly detected the onset and cessation of exercise with latencies ranging from 35 to 124 seconds. Pacemaker rate increase latency decreased as the exercise level was increased. Pacemaker response latency was not affected by the choice of resting or exercise pacing rate. These preliminary data indicate that right ventricular blood temperature can provide a reliable index to control pacemaker rate. An implantable temperature-controlled pacemaker using this algorithm is presently under long-term evaluation in dogs performing untethered exercise. PMID:6207490

Jolgren, D; Fearnot, N; Geddes, L

1984-09-01

390

Interference Between GSM Mobile Phones and Pace-Makers: In Vitro Evaluation of Interaction Mechanisms.  

National Technical Information Service (NTIS)

Aim of this study vas to in-vitro evaluate the effectiveness of the filtered feedthru assembly used to filter out the electromagnetic interference at the input stage of implantable pace-makers. We used three modified pace-makers of the same model, with an...

A. Angeloni B. Barbaro P. Bartolini G. Calcagnini F. Censi

2001-01-01

391

Adherence to lifestyle modifications after a cardiac rehabilitation program and endothelial progenitor cells. A six-month follow-up study.  

PubMed

An increase of endothelial progenitor cells (EPCs) among acute myocardial infarction (AMI) patients participating in a cardiac rehabilitation (CR) program has been reported, but no data on the impact of adherence to lifestyle recommendations provided during a CR program on EPCs are available. It was our aim to investigate the effect of adherence to lifestyle recommendations on EPCs, inflammatory and functional parameters after six months of a CR program in AMI patients. In 110 AMI patients (90 male/20 female; mean age 57.9 ± 9.4 years) EPCs, high sensitivity C-reactive protein (hsCRP), N-terminal pro-brain natriuretic peptide (NT-ProBNP) levels, and cardiopulmonary testings were determined at the end of the CR (T1) and at a six-month follow-up (T2). At T2 we administered a questionnaire assessing dietary habits and physical activity. At T2, we observed a decrease of EPCs (p<0.05), of hsCRP (p=0.009) and of NT-ProBNP (p<0.0001). Patient population was divided into three categories by Healthy Lifestyle (HL) score (none/low, moderate and high adherence to lifestyle recommendations). We observed a significant association between adherence to lifestyle recommendations, increase in EPCs and exercise capacity between T1 and T2 (? EPCs p for trend <0.05; ?Watt max p for trend=0.004). In a multivariate logistic regression analyses, being in the highest tertile of HL score affected the likelihood of an increase of EPC levels at T2 [OR (95% confidence interval): 3.36 (1.0-10.72) p=0.04]. In conclusion, adherence to lifestyle recommendations provided during a CR program positively influences EPC levels and exercise capacity. PMID:24573342

Cesari, F; Marcucci, R; Gori, A M; Burgisser, C; Francini, S; Roberts, A T; Sofi, F; Gensini, G F; Abbate, R; Fattirolli, F

2014-07-01

392

Multiple photoreceptor systems control the swim pacemaker activity in box jellyfish.  

PubMed

Like all other cnidarian medusae, box jellyfish propel themselves through the water by contracting their bell-shaped body in discrete swim pulses. These pulses are controlled by a swim pacemaker system situated in their sensory structures, the rhopalia. Each medusa has four rhopalia each with a similar set of six eyes of four morphologically different types. We have examined how each of the four eye types influences the swim pacemaker. Multiple photoreceptor systems, three of the four eye types, plus the rhopalial neuropil, affect the swim pacemaker. The lower lens eye inhibits the pacemaker when stimulated and provokes a strong increase in the pacemaker frequency upon light-off. The upper lens eye, the pit eyes and the rhopalial neuropil all have close to the opposite effect. When these responses are compared with all-eye stimulations it is seen that some advanced integration must take place. PMID:19946073

Garm, A; Mori, S

2009-12-01

393

Is magnetic resonance safe in implanted cardiac devices patients?  

PubMed

Nazarian et al. [1] evaluate in a prospective non-randomized trial the safety of a 1.5 T MRI protocol for patients with implanted cardiac devices (ICD and PM). 438 participants (54 % with PM and 46 % with ICD implanted, respectively,after the 1998 and 2000) were enrolled and underwent 555MRI examinations. Patients with a recent implant(\\6 weeks), those with abandoned or epicardiac leads, and PM-dependent patients with an ICD were excluded.According to the experimental protocol, an asynchronous pacing mode (VOO/DOO) was programmed in the pacemaker-dependent patients, while an inhibited pacing mode(VVI/DDI) was used for the other patients. The ICD function of non-PM-dependent patients was disabled. During the MRI examination, blood pressure, electrocardiography, pulse oximetry and symptoms were monitored by a nurse with experience in cardiac life support and device programming who had an immediate backup from an electrophysiologist.Device variables including sensing, impedance, capture threshold and battery voltage were evaluated before MRI examination, immediately after MRI and after 3–6 months.Variations exceeding 30, 40 and 50 %for, respectively, lead impedance, sensing and capture threshold were considered as significant changes in lead performance.Baseline and immediate follow-up interrogations were performed in all 438. Long-term follow-up device variables were available for 266 patients (61 %). 3 of 438 patients(0.7 %) experienced acute power-on-reset events. None of them had device dysfunction during long-term follow-up(3–6 months). Right ventricular sensing and atrial, right and left ventricular impedances were reduced immediately after MRI. At long-term follow-up in 61 % of the patients,decreased right ventricular (RV) sensing and lead impedance,increased RV capture threshold and decreased battery voltage were noted. The observed changes did not require device revision or reprogramming. The distributions of changes in device variables were within the 20 % at baseline for most participants. Thoracic MRI sequences had a greater effect on device variables and were more likely to result in artifacts (for instance, image distortion,signal voids or bright areas and poor fat suppression). PMID:22492008

Cernuschi, Giulia; Cringoli, Maurizio

2012-06-01

394

Norepinephrine differentially modulates different types of respiratory pacemaker and nonpacemaker neurons.  

PubMed

Pacemakers are found throughout the mammalian CNS. Yet, it remains largely unknown how these neurons contribute to network activity. Here we show that for the respiratory network isolated in transverse slices of mice, different functions can be assigned to different types of pacemakers and nonpacemakers. This difference becomes evident in response to norepinephrine (NE). Although NE depolarized 88% of synaptically isolated inspiratory neurons, this neuromodulator had differential effects on different neuron types. NE increased in cadmium-insensitive pacemakers burst frequency, not burst area and duration, and it increased in cadmium-sensitive pacemakers burst duration and area, but not frequency. NE also differentially modulated nonpacemakers. Two types of nonpacemakers were identified: "silent nonpacemakers" stop spiking, whereas "active nonpacemakers" spontaneously spike when isolated from the network. NE selectively induced cadmium-sensitive pacemaker properties in active, but not silent, nonpacemakers. Flufenamic acid (FFA), a blocker of ICAN, blocked the induction as well as modulation of cadmium-sensitive pacemaker activity, and blocked at the network level the NE-induced increase in burst area and duration of inspiratory network activity; the frequency modulation (FM) was unaffected. We therefore propose that modulation of cadmium-sensitive pacemaker activity contributes at the network level to changes in burst shape, not frequency. Riluzole blocked the FM of isolated cadmium-insensitive pacemakers. In the presence of riluzole, NE caused disorganized network activity, suggesting that cadmium-insensitive pacemakers are critical for rhythm generation. We conclude that different types of nonpacemaker and pacemaker neurons differentially control different aspects of the respiratory rhythm. PMID:16394066

Viemari, Jean-Charles; Ramirez, Jan-Marino

2006-04-01

395

Modeling cardiac mechano-electrical feedback using reaction-diffusion-mechanics systems  

NASA Astrophysics Data System (ADS)

In many practically important cases, wave propagation described by the reaction-diffusion equation initiates deformation of the medium. Mathematically, such processes are described by coupled reaction-diffusion-mechanics (RDM) systems. RDM systems were recently used to study the effects of deformation on wave propagation in cardiac tissue, so called mechano-electrical feedback (MEF). In this article, we review the results of some of these studies, in particular those relating to the effects of deformation on pacemaker activity and spiral wave dynamics in the heart. We also provide brief descriptions of the numerical methods used, and the underlying cardiac physiology.

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

2009-06-01

396

ERG K+ currents regulate pacemaker activity in ICC.  

PubMed

Ether-à-go-go-related gene (ERG) K channels have been implicated in the generation of pacemaker activities in the heart. To study the presence and function of ERG K channels in the pacemaker cells of the small intestine [the interstitial cells of Cajal (ICC)], a combination of patch-clamp techniques, tissue and live cell immunohistochemistry, RT-PCR, and in vitro functional studies were performed. Nonenzymatically isolated ICC in culture were identified by vital staining and presence of rhythmic inward currents. RT-PCR showed the presence of ERG mRNA in the intestinal musculature, and immunohistochemistry on tissue and cultured cells demonstrated that protein similar to human ERG was concentrated on ICC in the Auerbach's plexus region. Whole cell ERG K+ currents were evoked on hyperpolarization from 0 mV (but not from -70 mV) up to -120 mV and showed strong inward rectification. The currents were inhibited by E-4031, cisapride, La3+, and Gd3+ but not by 50 microM Ba2+. The ERG K+ inward current had a typical transient component with fast activation and inactivation kinetics followed by significant steady-state current. E-4031 also inhibited tetraethylammonium (TEA)-insensitive outward current indicating that the ERG K+ current is operating at depolarizing potentials. In contrast to TEA, blockers of the ERG K+ currents caused marked increase in tissue excitability as reflected by an increase in slow-wave duration and an increase in superimposed action potential activity. In summary, ERG K channels in ICC contribute to the membrane potential and play a role in regulation of pacemaker activity of the small intestine. PMID:12958021

Zhu, Yaohui; Golden, Catherine M; Ye, Jing; Wang, Xuan-Yu; Akbarali, Hamid I; Huizinga, Jan D

2003-12-01

397

Ionic Interconversion of Pacemaker and Nonpacemaker Cultured Chick Heart Cells  

PubMed Central

Trypsin-dispersed cells from hearts (ventricles) of 7 to 8 day chick embryos were cultured 3 to 21 days. The cells became attached to the culture dish and assembled into monolayer communities. By means of a bridge circuit, one microelectrode was used for simultaneously passing current and recording membrane potentials (Vm). The input resistance, calculated by the measured ?Vm for a known step of current, averaged 10 M?. Electrotonic depolarization of nonpacemaker cells had no effect on frequency of firing. Within 2 min after addition of Ba++ (5 to 10 mM) to the Tyrode bath, the cells became partially depolarized and quiescent nonpacemaker cells developed oscillations in Vm which led to action potentials. With time, the depolarization became nearly complete and the input resistance increased 2 to 10 times. During such sustained depolarizations, action potentials were no longer produced and often tiny oscillations were observed; however, large action potentials developed during hyperpolarizing pulses. Thus, the automaticity of the depolarized cell became apparent during artificial repolarization. Sr++ (5 to 10 mM) initially produced hyperpolarization and induced automaticity in quiescent nonpacemaker cells. Elevated [K+]o (20 to 30 mM) suppressed automaticity of pacemaker cells and decreased Rm concomitantly. Thus, Ba++ probably converts nonpacemaker cells into pacemaker cells independently of its depolarizing action. Ba++ may induce automaticity and depolarization by decreasing gK, and elevated [K+]o may depress automaticity by increasing gK. The data support the hypothesis that the level of gK determines whether a cell shall function as a pacemaker.

Sperelakis, Nick; Lehmkuhl, D.

1966-01-01

398

[General surgical procedures in patients with electrical pacemaker].  

PubMed

Work of the implanted electric pacemaker (EP) was assessed in 99 patients, aged 62.4±9.6 years, during non-cardiological surgery. Inhibition of the EP stimuli was registered in 9 (9.1%) patients, short episodes of uneffective stimulation with synchronization disturbation--in 2 (2%) patients and change of stimulation regimen was registered in the same number of patients by electocoagulation. Episodes of myopotential inhibition not assotiated with electrocoagulation was registered in 4 cases. The ascertained rhythm disturbances require a thorough preoperative check-up, intraoperative ECG control and short use of monopolar electrocoagulation. PMID:21164416

Sazhin, A V; Tiagunov, A E; Pervova, E V; Aleksandrov, A N; Rogov, K A; Zlotnikova, A D; Zhdanov, A M

2010-01-01

399

Cardiac sarcoidosis.  

PubMed

Cardiac sarcoidosis (CS) is a rare and under-recognized clinical entity that requires a high level of suspicion and low threshold for screening in order to make the diagnosis. CS may manifest in a variety of ways, and its initial presentation can range from asymptomatic electrocardiographic abnormalities to overt heart failure to sudden cardiac death. The aim of this literature review is to provide a comprehensive overview of CS, with an emphasis on clinical manifestations and special diagnostic and management considerations, while highlighting recent studies that have provided new insights into this unique disease. PMID:24969032

Zipse, Matthew M; Sauer, William H

2014-08-01

400

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

PubMed Central

Background The ability to apply standard and interoperable solutions for implementing and managing medical registries as well as aggregate, reproduce, and access data sets from legacy formats and platforms to advanced standard formats and operating systems are crucial for both clinical healthcare and biomedical research settings. Purpose Our study describes a reproducible, highly scalable, standard framework for a device registry implementation addressing both local data quality components and global linking problems. Methods and Results We developed a device registry framework involving the following steps: (1) Data standards definition and representation of the research workflow, (2) Development of electronic case report forms using REDCap (Research Electronic Data Capture), (3) Data collection according to the clinical research workflow and, (4) Data augmentation by enriching the registry database with local electronic health records, governmental database and linked open data collections, (5) Data quality control and (6) Data dissemination through the registry Web site. Our registry adopted all applicable standardized data elements proposed by American College Cardiology / American Heart Association Clinical Data Standards, as well as variables derived from cardiac devices randomized trials and Clinical Data Interchange Standards Consortium. Local interoperability was performed between REDCap and data derived from Electronic Health Record system. The original data set was also augmented by incorporating the reimbursed values paid by the Brazilian government during a hospitalization for pacemaker implantation. By linking our registry to the open data collection repository Linked Clinical Trials (LinkedCT) we found 130 clinical trials which are potentially correlated with our pacemaker registry. Conclusion This study demonstrates how standard and reproducible solutions can be applied in the implementation of medical registries to constitute a re-usable framework. Such approach has the potential to facilitate data integration between healthcare and research settings, also being a useful framework to be used in other biomedical registries.

da Silva, Katia Regina; Costa, Roberto; Crevelari, Elizabeth Sartori; Lacerda, Marianna Sobral; de Moraes Albertini, Caio Marcos; Filho, Martino Martinelli; Santana, Jose Eduardo; Vissoci, Joao Ricardo Nickenig; Pietrobon, Ricardo; Barros, Jacson V.

2013-01-01

401

Optimal algorithm switching for the estimation of systole period from cardiac microacceleration signals (SonR).  

PubMed

Previous studies have shown that cardiac microacceleration signals, recorded either cutaneously, or embedded into the tip of an endocardial pacing lead, provide meaningful information to characterize the cardiac mechanical function. This information may be useful to personalize and optimize the cardiac resynchronization therapy, delivered by a biventricular pacemaker, for patients suffering from chronic heart failure (HF). This paper focuses on the improvement of a previously proposed method for the estimation of the systole period from a signal acquired with a cardiac microaccelerometer (SonR sensor, Sorin CRM SAS, France). We propose an optimal algorithm switching approach, to dynamically select the best configuration of the estimation method, as a function of different control variables, such as the signal-to-noise ratio or heart rate. This method was evaluated on a database containing recordings from 31 patients suffering from chronic HF and implanted with a biventricular pacemaker, for which various cardiac pacing configurations were tested. Ultrasound measurements of the systole period were used as a reference and the improved method was compared with the original estimator. A reduction of 11% on the absolute estimation error was obtained for the systole period with the proposed algorithm switching approach. PMID:22893366

Giorgis, L; Frogerais, P; Amblard, A; Donal, E; Mabo, P; Senhadji, L; Hernández, A I

2012-11-01

402

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

403

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

PubMed Central

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

Cohen, I S; Mulrine, N K

1986-01-01

404

Cardiac Conduction through Engineered Tissue  

PubMed Central

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

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

2006-01-01

405

An improvement of a transcutaneous-energy transformer for a noninvasive rechargeable cardiac pacemaker battery  

Microsoft Academic Search

An improved method for a flat secondary transcutaneous transformer for a resonant converter that transfers several W of power across a large variable human skin gap is presented. The secondary transformer is piled, and the coupling coefficient, the conversion efficiency, the temperature rise are measured with an experimental set up. The coupling coefficient and the conversion efficiency are increased compared

T. H. Nishimura; T. Eguchi; T. Inoue; K. Hirachi; Y. Maejima; M. Saito

1996-01-01

406

A non invasive rechargeable cardiac pacemaker battery system with a transcutaneous energy transformer  

Microsoft Academic Search

The improvement method of a flat secondary transcutaneous transformer for a resonant converter that transfers several W of power across a large variable human skin gap is presented and built. The secondary transformer is piled, and the coupling coefficient, conversion efficiency and temperature rise are measured with an experimental set up. The coupling coefficient and the conversion efficiency are increased

T. H. Nishimura; T. Eguchi; A. Kubota; M. Hatori; M. Saito

1998-01-01

407

Implantable cardiac pacemaker electromagnetic compatibility testing in a novel security system Simulator  

Microsoft Academic Search

This work describes a novel simulator to perform electromagnetic compatibility (EMC) tests for active implantable medical devices (AIMDs) with electromagnetic fields emitted by security systems. The security system simulator was developed in response to over 100 incident reports over 17 years related to the interference of AIMD's with security systems and the lack of a standardized test method. The simulator

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

2005-01-01

408

Drug release mechanisms of steroid eluting rings in cardiac pacemaker lead electrodes.  

PubMed

This paper reports on the drug release mechanisms of silicone structures with embedded steroids applied in pacing leads. Different derivatives of the steroid dexamethasone, which is associated with the reduction of acute stimulation thresholds, were evaluated together with different matrix based release control mechanisms with the target to potentially match optimal drug release rates during the first month after implantation. By incorporating dexamethasone-21-dihydrogen phosphate in silicone matrices in combination with release rate adaption layers, almost continuous release rates were obtained under physiological test settings. PMID:23365984

Herrlich, Simon; Spieth, Sven; Gerstmann, Hans; Virnich, Astrid; Zipfel, Franz; Kitschmann, Achim; Goettsche, Thorsten; Osypka, Peter; Zengerle, Roland

2012-01-01

409

Cardiac Action and Pacemaker Potentials based on the Hodgkin-Huxley Equations  

Microsoft Academic Search

SINCE the equations describing the nerve action potential were formulated by Hodgkin and Huxley1, the range of phenomena to which they have been shown to apply has been greatly extended. Huxley2has applied them to the influence of temperature on the propagated response and to the repetitive firing observed in low calcium concentrations. More recently, Fitzhugh3 has shown that the long

D. Noble

1960-01-01

410

Pacemaker dynamics in the full Morris–Lecar model  

NASA Astrophysics Data System (ADS)

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.

González-Miranda, J. M.

2014-09-01

411

Phase shifting two coupled circadian pacemakers - Implications for jet lag  

NASA Technical Reports Server (NTRS)

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.

Gander, P. H.; Kronauer, R. E.; Graeber, R. C.

1985-01-01

412

Regional Difference in Dynamical Property of Sinoatrial Node Pacemaking: Role of Na+ Channel Current  

PubMed Central

To elucidate the regional differences in sinoatrial node pacemaking mechanisms, we investigated 1), bifurcation structures during current blocks or hyperpolarization of the central and peripheral cells, 2), ionic bases of regional differences in bifurcation structures, and 3), the role of Na+ channel current (INa) in peripheral cell pacemaking. Bifurcation analyses were performed for mathematical models of the rabbit sinoatrial node central and peripheral cells; equilibrium points, periodic orbits, and their stability were determined as functions of parameters. Structural stability against applications of acetylcholine or electrotonic modulations of the atrium was also evaluated. Blocking L-type Ca2+ channel current (ICa,L) stabilized equilibrium points and abolished pacemaking in both the center and periphery. Critical acetylcholine concentration and gap junction conductance for pacemaker cessation were higher in the periphery than in the center, being dramatically reduced by blocking INa. Under hyperpolarized conditions, blocking INa, but not eliminating ICa,L, abolished peripheral cell pacemaking. These results suggest that 1), ICa,L is responsible for basal pacemaking in both the central and peripheral cells, 2), the peripheral cell is more robust in withstanding hyperpolarizing loads than the central cell, 3), INa improves the structural stability to hyperpolarizing loads, and 4), INa-dependent pacemaking is possible in hyperpolarized peripheral cells.

Kurata, Yasutaka; Matsuda, Hiroyuki; Hisatome, Ichiro; Shibamoto, Toshishige

2008-01-01

413

Left Ventricular Synchrony and Function in Pediatric Patients with Definitive Pacemakers  

PubMed Central

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.

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

2013-01-01

414

The evolution of the cardiac implantable electronic device connector.  

PubMed

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

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

2013-11-01

415

Nonlinear dynamics of the heartbeat II. Subharmonic bifurcations of the cardiac interbeat interval in sinus node disease  

NASA Astrophysics Data System (ADS)

Changing the coupling of electronic relaxation oscillators may be associated with the emergence of complex periodic behavior. The electrocardiographic record of a patient with the “sick sinus syndrome” demonstrated periodic behavior including subharmonic bifurcations in an attractor of his interbeat interval. Such nonlinear dynamics which may emerge from alterations in the coupling of oscillating pacemakers are not predicted by traditional models in cardiac electrophysiology. An understanding of the nonlinear behavior of physical and mathematical systems may generalize to pathophysiological processes.

Goldberger, Ary L.; Bhargava, Valmik; West, Bruce J.; Mandell, Arnold J.

1985-10-01

416

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

PubMed

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

van Gelder, L M; El Gamal, M I

1983-09-01

417

Cardiac optogenetics  

PubMed Central

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.

2013-01-01

418

Cardiac optogenetics.  

PubMed

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

Entcheva, Emilia

2013-05-01

419

Predictors of short-term (seven-day) cardiac outcomes after emergency department visit for syncope.  

PubMed

Syncope is a common reason for emergency department (ED) visits, and patients are often admitted to exclude syncope of cardiovascular origin. Population-based data on patterns and predictors of cardiac outcomes may improve decision-making. Our objective was to identify patterns and predictors of short-term cardiac outcomes in ED patients with syncope. Administrative data from an integrated health system of 11 Southern California EDs were used to identify cardiac outcomes after ED presentation for syncope from January 1, 2002, to December 31, 2005. Syncope and cause of death were identified by codes from the International Classification of Disease, Ninth Revision. Cardiac outcomes included cardiac death and hospitalization or procedure consistent with ischemic heart disease, valvular disease, or arrhythmia. Predictors of cardiac outcomes were identified through multivariate logistic regression. There were 35,330 adult subjects who accounted for 39,943 ED visits for syncope. Risk of cardiac outcome sharply decreased following the 7 days after syncope. A 7-day cardiac outcome occurred in 893 cases (3%). Positive predictors of 7-day cardiac outcomes included age > or =60 years, male gender, congestive heart failure, ischemic heart disease, cardiac arrhythmia, and valvular heart disease. Negative predictors included dementia, pacemaker, coronary revascularization, and cerebrovascular disease. There was an age-dependent relation between 7-day cardiac outcomes and arrhythmia and valvular disease, with younger patients (<60 years of age) having greater risk of an event compared to their same-age counterparts. In conclusion, ED decision-making should focus on risk of cardiac event in the first 7 days after syncope and special attention should be given to younger patients with cardiac co-morbidities. PMID:20102895

Gabayan, Gelareh Z; Derose, Stephen F; Asch, Steven M; Chiu, Vicki Y; Glenn, Sungching C; Mangione, Carol M; Sun, Benjamin C

2010-01-01

420

Predictors of Short Term (7-Day) Cardiac Outcomes after Emergency Department Visit for Syncope  

PubMed Central

Syncope is a common reason for emergency department (ED) visits, and patients are often admitted to exclude syncope of cardiovascular origin. Population based data on patterns and predictors of cardiac outcomes may improve decision-making. Our objective was to identify patterns and predictors of short-term cardiac outcomes in ED patients with syncope. Administrative data from an integrated health system of 11 Southern California EDs were used to identify cardiac outcomes after ED presentation for syncope from 1/1/02-12/31/05. Syncope and cause of death were identified by ICD-9 codes. Cardiac outcomes included cardiac death and hospitalization or procedure consistent with ischemic heart disease, valvular disease or arrhythmia. Predictors of cardiac outcomes were identified through multivariate logistic regression. There were 35,330 adult subjects who accounted for 39,943 ED visits for syncope. The risk of cardiac outcome sharply decreased following the 7 days post syncope. A 7-day cardiac outcome occurred in 893 cases (3%). Positive predictors of 7-day cardiac outcomes included age ? 60, male gender, congestive heart failure, ischemic heart disease, cardiac arrhythmia, and valvular heart disease. Negative predictors included dementia, pacemaker, coronary revascularization, and cerebrovascular disease. There was an age-dependent relationship between 7-day cardiac outcomes and arrhythmia and valvular disease, with younger patients (age <60 years) experiencing greater risk of an event compared to their same age counterparts. In conclusion, ED decision-making should focus on risk of cardiac event in the first 7-days after syncope and special attention should be given to younger patients with cardiac comorbidities.

Gabayan, Gelareh Z.; Derose, Stephen F.; Asch, Steven M.; Chiu, Vicky Y.; Glenn, Sungching C.; Mangione, Carol M.; Sun, Benjamin C.

2010-01-01

421

A Sodium Leak Current Regulates Pacemaker Activity of Adult Central Pattern Generator Neurons in Lymnaea Stagnalis  

PubMed Central

The resting membrane potential of the pacemaker neurons is one of the essential mechanisms underlying rhythm generation. In this study, we described the biophysical properties of an uncharacterized channel (U-type channel) and investigated the role of the channel in the rhythmic activity of a respiratory pacemaker neuron and the respiratory behaviour in adult freshwater snail Lymnaea stagnalis. Our results show that the channel conducts an inward leak current carried by Na+ (ILeak-Na). The ILeak-Na contributed to the resting membrane potential and was required for maintaining rhythmic action potential bursting activity of the identified pacemaker RPeD1 neurons. Partial knockdown of the U-type channel suppressed the aerial respiratory behaviour of the adult snail in vivo. These findings identified the Na+ leak conductance via the U-type channel, likely a NALCN-like channel, as one of the fundamental mechanisms regulating rhythm activity of pacemaker neurons and respiratory behaviour in adult animals.

Lu, Tom Z.; Feng, Zhong-Ping

2011-01-01

422

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

PubMed Central

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.

Verkerk, Arie O.

2013-01-01

423

Behavior of an Automatic Pacemaker Sensing Algorithm for Single-Pass VDD Atrial Electrograms.  

National Technical Information Service (NTIS)

Single-pass VDD pacemakers have been used as a result of simple implantation procedures and generally reliable atrial tracking. However, there is a controversy over their reliabilities of atrial tracking. As a new sensing method for reliable atrial tracki...

J. Kim S. H. Lee S. Y. Yang B. S. Cho W. Huh

2001-01-01

424

Engineering a biological pacemaker: in vivo, in vitro and in silico models  

PubMed Central

Several hundred thousand electronic pacemakers are implanted in the US each year to treat abnormally slow heart rates. Biological pacemaker research strives to replace this hardware, and the associated monitoring and maintenance, by using gene or cell therapy to create a permanent and autonomically responsive pacemaker. While there are numerous technological hurdles to overcome before this is a therapeutic reality, one critical issue is determining the optimal channel gene to employ in creating a biological pacemaker. This review discusses the pros and cons of various model systems for characterizing and evaluating the function of candidate channel genes. It is argued that a sequential approach that combines in silico, in vitro and in vivo models is required.

Robinson, Richard B.

2009-01-01

425

An Unusual Cause of Transient Ischemic Attack in a Patient with Pacemaker  

PubMed Central

Pacemaker lead malposition in various locations has been described in the literature. Lead malposition in left ventricle is a rare and an underdiagnosed complication. We present a 77-year-old man with history of atrial fibrillation and pacemaker placement who was admitted for transient ischemic attack. He was on aspirin, beta blocker, and warfarin with subtherapeutic international normalized ratio. His paced electrocardiogram showed right bundle-branch block, rather than the typical pattern of left bundle-branch block, suggesting pacemaker lead malposition. Further, his chest X-ray and echocardiogram confirmed the pacemaker lead position in the left ventricle instead of right ventricle. He refused surgical removal of the lead and we increased his warfarin dose. Diagnosis of lead malposition in left ventricle, though easy to identify in echocardiogram, requires high index of clinical suspicion. In asymptomatic patients, surgical removal may be deferred for treatment with lifelong anticoagulation.

Kalavakunta, Jagadeesh Kumar; Gupta, Vishal; Paulus, Basil; Lapenna, William

2014-01-01

426

Pacemaker activity resulting from the coupling with nonexcitable cells  

NASA Astrophysics Data System (ADS)

Fibroblasts are nonexcitable cells that are sometimes coupled with excitable cells (cardiomyocytes). Due to a higher resting potential, these cells may act as a current source or sink and therefore disturb the electrical activity of the surrounding excitable cells. The possible occurrence of spontaneous pacemaker activity resulting from these electrotonic interactions was investigated in a theoretical model of two coupled cells as well as in a multicellular fiber model based on the Courtemanche kinetics. The results indicate that repeated spontaneous activations can be observed after an alteration in the activation and recovery properties of the sodium current (changes in excitability properties), provided that the difference in the resting potential as well as the coupling between the excitable and nonexcitable cells is sufficiently high. This may constitute a mechanism of focal sources triggering arrhythmias such as atrial fibrillation.

Jacquemet, Vincent

2006-07-01

427

The Drosophila Circadian Pacemaker Circuit: Pas de Deux or Tarantella?  

PubMed Central

Molecular genetic analysis of the fruit fly Drosophila melanogaster has revolutionized our understanding of the transcription/translation loop mechanisms underlying the circadian molecular oscillator. More recently, Drosophila has been used to understand how different neuronal groups within the circadian pacemaker circuit interact to regulate the overall behavior of the fly in response to daily cyclic environmental cues as well as seasonal changes. Our present understanding of circadian timekeeping at the molecular and circuit level is discussed with a critical evaluation of the strengths and weaknesses of present models. Two models for circadian neural circuits are compared: one that posits that two anatomically distinct oscillators control the synchronization to the two major daily morning and evening transitions, versus a distributed network model that posits that many cell-autonomous oscillators are coordinated in a complex fashion and respond via plastic mechanisms to changes in environmental cues.

Sheeba, Vasu; Kaneko, Maki; Sharma, Vijay Kumar; Holmes, Todd C.

2008-01-01

428

Sutureless epicardial pacemaker lead: a satisfactory preliminary experience.  

PubMed

The first pacemaker systems used the epicardial electrode. The transvenous endocardial electrode rapidly supplanted the epicardial electrode since it could be positioned with less morbidity and mortality and was associated with a lower incidence of wire breakage. The long term complication rate of the transvenous electrode had not been inconsequential. The sutureless epicardial electrode combines the greater reliability of the epicardial lead system with the ease of insertion and low morbidity of the endocardial lead system. We have used this electrode in 33 patients. The electrode was positioned using the subxiphoid approach and local anesthesia in most patients. There have been few complications and none that resulted in long term morbidity. There have been no deaths related either to the operative approach or to the pacing system. There has been no instance of lead failure during the follow-up period. PMID:123845

Stewart, S; Cohen, J; Murphy, G

1975-05-01

429

Characterization of spontaneous and chemically induced cardiac lesions in rodent model systems: the national toxicology program experience.  

PubMed

Induction of heart disease can be related to exposure to a number of agents, including environmental chemicals. Studies with laboratory rodents are commonly used to identify cardiotoxic agents and to investigate mechanisms of toxicity. This study was conducted to characterize spontaneous and chemically-induced rodent heart lesions. A retrospective light-microscopic evaluation was performed on the hearts of F344 rats and B6C3F1 mice from National Toxicology Program studies of six chemicals in which chemically-induced myocardial toxicity was present: oxymetholone, monochloroacetic acid, 3,3'-4,4'- tetrachoroazoxybenzene, diethanolamine, urethane, and methyl bromide. Two myocardial lesions were observed: cardiomyopathy (multifocal myofiber degeneration that could occur spontaneously or as a treatment effect) and degeneration (diffuse myofiber degeneration that was clearly related to treatment). Oxymetholone produced cardiotoxicity that was apparent as an increase in the incidence and average severity of cardiomyopathy. The remaining five chemicals produced degeneration, which appeared morphologically similar with each of the chemicals. Based on available information concerning possible mechanisms by which each of these chemicals may induce cardiotoxicity, this evaluation indicated it may be possible to place the chemicals into two main categories: (1) those that primarily affected the coronary vasculature with secondary effects on the myocardium (oxymetholone), and (2) those that had a direct toxic effect on the myocardial cells (the remaining five chemicals). Beyond this, however, light-microscopic findings did not indicate any specific mechanisms. Additional morphologic evaluations, such as electron microscopy or special histochemical or immunostains, may help identify specific subcellular sites of toxic damage, which in turn can indicate appropriate types of molecular mechanistic studies. PMID:16046796

Jokinen, Micheal P; Lieuallen, Warren G; Johnson, Crystal L; Dunnick, June; Nyska, Abraham

2005-01-01

430

Two cases of cardiac device-related endocarditis due to Streptococcus dysgalactiae subsp. equisimilis (group C or G streptococci)  

PubMed Central

Background Cardiac device-related endocarditis is a very rare clinical manifestation of S. dysgalactiae subsp. equisimilis disease. This pathogen is a common cause of cellulitis. We here report two cases of cardiac device-related endocarditis due to Streptococcus dysgalactiae subsp. equisimilis. Blood cultures yielded this pathogen and both patients had recurrent bacteremia. Transthoracic and transesophageal echocardiography revealed lead vegetations. This is a new description of this pathogen to cause cardiac device-related endocarditis. Case presentation The first case is a 79-year-old finnish woman who received a dual-chamber pacemaker for intermittent complete heart block in April 2011. She had three episodes of S. dysgalactiae subsp. equisimilis bacteremia. During first episode she had arthritis of glenohumeral joint. Focus was unknown in the second and third bacteremic episodes. During third bacteremic episode transesophageal echocardiography (TEE) revealed lead vegetation. Patient underwent successful complete system removal. She was treated with benzylpenicillin four million IU six times a day for four weeks intravenously. The second case is a 92-year-old finnish man. A dual-chamber pacemaker was implanted on June 2012 due to total heart block. He had recurrent S. dysgalactiae subsp. equisimilis bacteremia with cellulitis. During the second bacteremic episode transthoracic echocardiography (TTE) was performed because of persistent fever. Echocardiography revealed lead vegetation. Abdominal CT revealed also an abscess in the psoas region. This elderly patient was very fragile, and the pacemaker system was not extracted. Therapy was continued with benzylpenicillin four million IU six times a day for six weeks intravenously and thereafter suppressive treatment with amoksisillin 500 mg three times a day was initiated. Conclusion Streptococcus dysgalactiae subsp. equisimilis (group C and G streptococci) seldom cause cardiac device endocarditis. Both patients had recurrent bacteremia of S. dysgalactiae subsp. equisimilis and echocardiography revealed cardiac device-related endocarditis. These cases emphasize the importance of considering endocarditis in elderly persons having cardiac devices together with the presence of unexplained bacteremia, fever without focus or persistent fever.

2014-01-01

431

Inward-rectifying potassium (Kir) channels regulate pacemaker activity in spinal nociceptive circuits during early life  

PubMed Central

Pacemaker neurons in neonatal spinal nociceptive circuits generate intrinsic burst-firing and are distinguished by a lower “leak” membrane conductance compared to adjacent, non-bursting neurons. However, little is known about which subtypes of leak channels regulate the level of pacemaker activity within the developing rat superficial dorsal horn (SDH). Here we demonstrate that a hallmark feature of lamina I pacemaker neurons is a reduced conductance through inward-rectifying potassium (Kir) channels at physiological membrane potentials. Differences in the strength of inward rectification between pacemakers and non-pacemakers indicate the presence of functionally distinct Kir currents in these two populations at room temperature. However, Kir currents in both groups showed high sensitivity to block by extracellular Ba2+ (IC50 ~ 10 µM), which suggests the presence of ‘classical’ Kir (Kir2.x) channels in the neonatal SDH. The reduced Kir conductance within pacemakers is unlikely to be explained by an absence of particular Kir2.x isoforms, as immunohistochemical analysis revealed the expression of Kir2.1, Kir2.2 and Kir2.3 within spontaneously bursting neurons. Importantly, Ba2+ application unmasked rhythmic burst-firing in ~42% of non-bursting lamina I neurons, suggesting that pacemaker activity is a latent property of a sizeable population of SDH cells during early life. In addition, the prevalence of spontaneous burst-firing within lamina I was enhanced in the presence of high internal concentrations of free Mg2+, consistent with its documented ability to block Kir channels from the intracellular side. Collectively, the results indicate that Kir channels are key modulators of pacemaker activity in newborn central pain networks.

Li, Jie; Blankenship, Meredith L.; Baccei, Mark L.

2013-01-01

432

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

PubMed Central

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

2014-01-01