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1

Radioisotope Powered Cardiac Pacemakers  

Microsoft Academic Search

Over 50, 000 implantable cardiac pacemakers are in use to rehabilitate patients with heart block. The chemical batteries powering these pacemakers usually fail within a few years. A variety of nuclear batteries, with the potential of providing long-lived (10 - 20 years) pacemaker power, are under development. This paper reviews the status of this development. Nuclear-powered pacemakers have reached the

F. N. Huffman; J. J. Migliore; W. J. Robinson; J. C. Norman

1974-01-01

2

Quarterly Progress Report for Radioisotope Powered Cardiac Pacemaker Program, August 1, 1973-October 31, 1973.  

National Technical Information Service (NTIS)

Progress is reported on the development of a radioisotope powered cardiac pacemaker. The developmental work is discussed under the following tasks: Program management; control and planning; reliability and quality assurance; system fabrication and product...

1973-01-01

3

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

4

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

5

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

Code of Federal Regulations, 2013 CFR

...false External transcutaneous cardiac pacemaker (noninvasive). 870.5550 Section...5550 External transcutaneous cardiac pacemaker (noninvasive). (a) Identification. An external transcutaneous cardiac pacemaker (noninvasive) is a device...

2013-04-01

6

Echocardiography-guided pacemaker programming can improve cardiac hemodynamics in patients undergoing transcatheter aortic valve replacement.  

PubMed

Transcatheter aortic valve replacement (TAVR) is an effective treatment option for patients with severe aortic stenosis who are at high surgical risk because of multiple comorbidities. Many of these patients have been treated with pacemakers for concomitant conduction disease. The combination of severe aortic stenosis, cardiomyopathy, and conduction abnormalities results in a state of low cardiac output. Here, we report 2 complex TAVR cases where Doppler echocardiography was used to guide adjustment of device settings, leading to improved cardiac hemodynamic profiles. PMID:23627861

Lee, Ming-Sum; Naqvi, Tasneem Z

2013-04-29

7

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

8

Sacral neuromodulation and cardiac pacemakers  

Microsoft Academic Search

Introduction and hypothesis  Potential for cross-talk between cardiac pacemakers and sacral neuromodulation remains speculative.\\u000a \\u000a \\u000a \\u000a Methods  We present a case series of patients with cardiac pacemakers who underwent staged Interstim (Medtronic, Minneapolis, MN) implantation\\u000a and patients who had pulse generator implantation who later required cardiac pacemakers.\\u000a \\u000a \\u000a \\u000a \\u000a Results  No cross-talk was demonstrated in either group.\\u000a \\u000a \\u000a \\u000a Conclusions  Sacral neuromodulation appears to be safe in the setting of

Ted M. Roth

2010-01-01

9

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

Code of Federal Regulations, 2010 CFR

...2009-04-01 false External transcutaneous cardiac pacemaker (noninvasive). 870.5550...870.5550 External transcutaneous cardiac pacemaker (noninvasive). (a) Identification. An external transcutaneous cardiac pacemaker (noninvasive) is a...

2009-04-01

10

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

Code of Federal Regulations, 2010 CFR

...2010-04-01 false External transcutaneous cardiac pacemaker (noninvasive). 870.5550...870.5550 External transcutaneous cardiac pacemaker (noninvasive). (a) Identification. An external transcutaneous cardiac pacemaker (noninvasive) is a...

2010-04-01

11

The Dynamics of Competing Cardiac Pacemakers  

NASA Astrophysics Data System (ADS)

The modern theory of the dynamics of interacting oscillators has been applied to the analysis of heartbeat interval sequences in order to understand and predict the patterns of occurrence and timing of cardiac rhythm disturbances. The principal new contributions resulting from this research include: (1) The derivation of the symbolic dynamics of uncoupled cardiac pacemakers. (2) The geometric formulation of the interaction of coupled cardiac pacemakers as trajectories on the torus. (3) The derivation of a geometrical transformation of the heart beat interval sequence to the coupling function linking the activity of competing cardiac pacemakers. (4) The development of a transformation of the sequence of heart beat intervals which discriminates cardiac arrhythmias which result from anomalous pathways in the conduction system from those which result from competing pacemakers. (5) The formulation and testing through clinical case studies of a mathematical model which relates changes in heart rate to changes in the frequency of the occurrence of cardiac arrhythmias.

de Paola, Robert

12

Creating a cardiac pacemaker by gene therapy  

Microsoft Academic Search

While electronic cardiac pacing in its various modalities represents standard of care for treatment of symptomatic bradyarrhythmias\\u000a and heart failure, it has limitations ranging from absent or rudimentary autonomic modulation to severe complications. This\\u000a has prompted experimental studies to design and validate a biological pacemaker that could supplement or replace electronic\\u000a pacemakers. Advances in cardiac gene therapy have resulted in

Traian M. Anghel; Steven M. Pogwizd

2007-01-01

13

Creating a Cardiac Pacemaker by Gene Therapy  

Microsoft Academic Search

While electronic cardiac pacing in its various modalities represents standard of care for treatment of symptomatic bradyarrhythmias\\u000a and heart failure, it has limitations ranging from absent or rudimentary autonomic modulation to severe complications. This\\u000a has prompted experimental studies to design and validate a biological pacemaker that could supplement or replace electronic\\u000a pacemakers. Advances in cardiac gene therapy have resulted in

Traian M. Anghel; Steven M. Pogwizd

14

THE ARTIFICIAL CARDIAC PACEMAKER. INDICATIONS FOR IMPLANTATION.  

PubMed

Extensive clinical experience has demonstrated that implantable cardiac pacemakers are safe and effective mechanisms for controlling symptoms and preventing the hazards of third degree heart block with Stokes-Adams syncope. Medical management of this disease does not provide reliable protection and life expectancy averages about two years after diagnosis. Hence the negligible surgical morbidity and mortality associated with pacemaker implantation justifies broad indications to implant one of the four commercially available battery-powered units. ELECTIVE IMPLANTATION OF A PACEMAKER SHOULD BE CONSIDERED IN PATIENTS WITH PERSISTENT THIRD DEGREE HEART BLOCK WHO HAVE HAD: One or more episodes of Stokes-Adams syncope; surgical injury to the conduction system, regardless of syncopal attacks; evidence of low cardiac output with cardiomegaly secondary to bradycardia. Few if any other cardiac arrythmias are satisfactorily controlled by an electrical pacemaker. Emergency pacemaker control is obviously necessary for patients developing intractable or recurrent bouts of asystole. During the interval until an implantable unit can be obtained and sterilized, the patient may be controlled by intravenous isoproterenol or by an external pacemaker attached to a transvenous catheter electrode, a precordial skin electrode or a percutaneous myocardial wire electrode. PMID:14236028

ROE, B B; BRUNS, D L

1964-12-01

15

Cardiac pacing for bradycardia support: Evidence-based approach to pacemaker selection and programming  

Microsoft Academic Search

Opinion statement  The vast majority of pacemakers implanted in the United States for the treatment of symptomatic bradycardia are dual-chamber\\u000a systems with a complex array of functions, such as rate responsiveness, dynamic atrioventricular delay, and automatic mode\\u000a switching. Basic hemodynamic studies have convincingly demonstrated the superiority of maintaining atrioventricular synchrony.\\u000a However, clinical trials have failed to demonstrate the impressive results expected

Israel Galtes; Gervasio A. Lamas

2004-01-01

16

Endocrine and psychologic responses of patients to cardiac pacemaker implantation.  

PubMed

The findings that all HPA and SAM indexes increased during the first postoperative days strongly suggest that transvenous, permanent cardiac pacemaker implantation is a stressor. Since the psychologic tests did not demonstrate marked changes in anxiety or affective mood states, and the former was only weakly related to the endocrine responses, psychologic stimuli cannot be ascribed a prominent role in causing the observed endocrine alterations. Thus, the data suggest that physiologic stressors, such as surgical trauma and the irritation of the tissue surrounding the pacemaker, were the primary stimuli that activated the HPA and SAM systems. Although the structured teaching program resulted in a marked improvement of the treatment groups's knowledge of the device and the follow-up care it requires, it did not affect the endocrine or psychologic responses of patients to cardiac pacemaker implantation. PMID:3654241

Lanuza, D M; Marotta, S F

1987-09-01

17

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

18

Cardiac pacemaker: 15 years of "new" interpretation.  

PubMed

After more than 15 years since the "new" interpretation of the Purkinje fibre's pacemaker current was proposed, much progress has been made in the understanding of the basic functional principles of cardiac pacemaking. We now know that, in both the SA node and Purkinje fibres, the diastolic depolarization is generated by the interplay of several ionic components, the key process being represented by the turning-on of the hyperpolarization-activated i(f) current towards the end of the action potential repolarization phase. The properties of i(f) are well suited not only to generate, but also to mediate the control of cardiac rate by autonomic transmitters. This control is exerted through modulation of adenylate-cyclase and of cAMP, and allows a fine and rapid adjustment of heart rate to the changing needs of our normal day-life. Still, several problems remain to be clarified : for example, it is not clear how the degree of involvement of i(f) and other components changes in different areas of the nodal region, and whether this process is under control of the autonomic nervous system; more importantly, it is still unknown if the pacemaking mechanisms are similar in the newborn and in the adult, or if developmental changes in the way pacemaker activity is generated and modulated exist. PMID:8932564

DiFrancesco, D

1995-01-01

19

Catecholamines and development of cardiac pacemaking: An intrinsically intimate relationship  

Microsoft Academic Search

A generation ago, a melding of imagination and experimental evidence led to the hypothesis that catecholamines were essential in establishing basal cardiac pacemaking rhythm. Subsequent discoveries of depolarizing \\

Steven N. Ebert; David G. Taylor

2006-01-01

20

[Titanium nitride cardiac pacemaker electrodes].  

PubMed

The sensing and pacing performance of pacemaker electrodes is characterized by the electrochemical properties of the electrodes/tissue layer; the usually smooth metallic electrode surface results in a high pass filter characteristic. Consequently, the detected intracardiac signals, which control the implantable systems, are not optimally matched to the spectral contents of the depolarisation signal. To avoid interference caused by noise (EMI, muscle potentials, etc.) a shift of the frequency of the band pass towards the lower frequency spectrum is required. As previously reported, the electrochemical properties of sintered and surface-treated electrodes prove the predicted improvement of sensing performance if titanium-nitride coated electrodes are used. Our results demonstrate their superiority above all the other electrodes presently known. The advantages can be referred to the micro-crystalline surface structure achieved by sputter-deposited electrode coatings and the kinetics of the ionic exchange. Furthermore, the acute thresholds achieved with the TiN-systems were significantly better than those of the smooth metallic surface. These results were also confirmed for chronic implants and are attributable to the known biocompatibility of titanium and its alloys. PMID:2775825

Schaldach, M; Hubmann, M; Hardt, R; Weikl, A

21

Heart pacemaker - discharge  

MedlinePLUS

Cardiac pacemaker implantation - discharge; Artificial pacemaker - discharge; Permanent pacemaker - discharge; Internal pacemaker - discharge; Cardiac resynchronization therapy - discharge; CRT - discharge; Biventricular pacemaker - discharge

22

A new multiprogrammable isotopic powered cardiac pacemaker  

SciTech Connect

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

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

1982-09-01

23

Use of cardiac pacemakers in Britain.  

PubMed Central

In Britain during 1975 cardiac pacemakers were implanted at the rate of 56 new patients per million population. This is about one-third the rate for other Western countries but still represents an increase of 150% since 1972. Six-thousand generators were used, and apparatus worth about 2m pounds was implanted. Over 90% of the initial implantations were by the transvenous route, and the mortality from this operation was only 0-3%. Electrode repositioning was needed in 10% of cases. The average age of patients at the time of first implantation was 70. Most patients with pacemakers were able to obtain driving licenses and insurance; only 10% had to pay an additional premium. There is no evidence from insurance comparnies that such patients have an increased risk of accidents. Patients who wished to undertake paid employment almost always did so, often in their previous job. About 80% of the patients were able to increase or maintain their leisure activities at the same level of effort as before pacing became necessary. The number of implantations may be expected to increase by about three times over the next five years.

Sowton, E

1976-01-01

24

Wireless phones and cardiac pacemakers: in vitro interaction study  

Microsoft Academic Search

This paper summarizes the results of the large-scale in vitro investigation of the interaction between wireless phones and cardiac pacemakers conducted by the Center for the Study of Wireless Electromagnetic Compatibility at the University of Oklahoma. The research focused on testing 29 pacemaker models with 5 different phone standards to (1) evaluate the amount of interaction between wireless phones and

R. E. Schlegel; F. H. Grant

1997-01-01

25

Cellular Automata Model of Cardiac Pacemaker  

NASA Astrophysics Data System (ADS)

A network of Greenberg-Hasting cellular automata with cyclic intrinsic dynamics F rightarrow R rightarrow A rightarrow F rightarrow ... is shown to be a reliable approximation to the cardiac pacemaker. The three possible cell's states F, R, A are characterized by fixed timings { nF, nR, nA } -- time steps spent in each state. Dynamical properties of a simple line network are found to be critical with respect to the relation between nF and nR. The properties of a network arisen from a square lattice where some edges are rewired (locally and with the preference to link to cells which are more connected to other cells) are also studied. The resulted system evolves rhythmically with the period determined by timings. The emergence of a small group of neighboring automata where the whole system activity initiates is observed. The dominant evolution is accompanied with other rhythms, characterized by longer periods.

Makowiec, D.

2008-05-01

26

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

27

Effects of Electromagnetic Interference (2450 MHz) on Cardiac Pacemakers.  

National Technical Information Service (NTIS)

Tests were performed to determine the effects of 2450 MHz radiofrequency radiation on implantable cardiac pacemakers from various manufacturers. Of the 25 units tested, 11 had been implanted in large anesthetized dogs and 14 were in air (free field). Most...

W. D. Hurt

1973-01-01

28

Proton Beam Therapy Interference With Implanted Cardiac Pacemakers  

SciTech Connect

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

Oshiro, Yoshiko [Department of Radiation Oncology, University of Tsukuba, Ibaraki (Japan)], E-mail: ooyoshiko@pmrc.tsukuba.ac.jp; Sugahara, Shinji [Department of Radiation Oncology, University of Tsukuba, Ibaraki (Japan); Noma, Mio; Sato, Masato; Sakakibara, Yuzuru [Department of Cardiovascular Surgery, University of Tsukuba, Ibaraki (Japan); Sakae, Takeji [Proton Medical Research Center, University of Tsukuba, Ibaraki (Japan); Hayashi, Yasutaka [Department of Radiation Oncology, University of Tsukuba, Ibaraki (Japan); Nakayama, Hidetsugu; Tsuboi, Koji; Fukumitsu, Nobuyoshi [Department of Radiation Oncology, University of Tsukuba, Ibaraki (Japan); Proton Medical Research Center, University of Tsukuba, Ibaraki (Japan); Kanemoto, Ayae [Department of Radiation Oncology, University of Tsukuba, Ibaraki (Japan); Hashimoto, Takayuki [Division of Radiation Oncology, Shizuoka Cancer Center Hospital, Shizuoka (Japan); Tokuuye, Koichi [Department of Radiation Oncology, University of Tsukuba, Ibaraki (Japan); Proton Medical Research Center, University of Tsukuba, Ibaraki (Japan)

2008-11-01

29

Direct activation of cardiac pacemaker channels by intracellular cyclic AMP  

Microsoft Academic Search

CYCLIC AMP acts as a second messenger in the modulation of several ion channels1-9 that are typically controlled by a phosphorylation process10. In cardiac pacemaker cells, adrenaline and acetylcholine regulate the hyperpolarization-activated current (if), but in opposite ways; this current is involved in the generation and modulation of pacemaker activity11. These actions are mediated by cAMP and underlie control of

Dario Difrancesco; Paolo Tortora

1991-01-01

30

[Modern cardiac pacing. II. Rate responsive pacemakers: clinical experience].  

PubMed

Rate responsive cardiac pacemakers adapting their pacing frequency according to physical effort are able to solve not only a bradycardia, but a chronotropic incompetence too. 23 rate responsive pulse generators, implanted in 1987-1991 in our center, simulated the physiological conditions and in this way they significantly improved both working capacity in bicycle stress test (p < 0.0001) and well-being in comparison with ordinary demand pacers. The incidence of complications did not exceed that in simple common pacemakers, but the rate adaptive ones were expensive and their programming was time consuming. In all three rate adaptive principles used their non-specific response revealed some imperfection of sensor driven devices. In addition, both in QT and in respiratory dependent systems their pretty proportional frequency response was delayed, while the irregular pacing rate in body activity sensor was not very proportionate to the physical exercise. The non-specific sensor response may be reduced by a combination of biologic sensors. PMID:1296346

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

1992-12-01

31

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

SciTech Connect

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

Frazier, M.J.

1980-08-01

32

Modeling cardiac pacemakers with relaxation oscillators  

NASA Astrophysics Data System (ADS)

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

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

2004-05-01

33

Plethyzmography in assessment of hemodynamic results of pacemaker functions programming  

NASA Astrophysics Data System (ADS)

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

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

2011-01-01

34

Pacemaker  

MedlinePLUS

... Search Form Advanced Search Search the NHLBI, use radio buttons below to select whole site or Disease and Conditions Index only NHLBI Entire ... What Is ... Who Needs How Does a Pacemaker Work During Pacemaker Surgery After Pacemaker Surgery What Are ...

35

Permanent cardiac pacing after a cardiac operation: Predicting the use of permanent pacemakers  

Microsoft Academic Search

Background. The need for permanent cardiac pacing after cardiac operations is infrequent but associated with increased morbidity and resource utilization. We identified patient risk factors for pacemaker insertion to enable development of a predictive model.Methods. Data were collected prospectively for 10,421 consecutive patients who had cardiac operations between January 1990 and December 1995. Two hundred fifty-five patients (2.4%) were identified

Richard S Gordon; Joan Ivanov; Gideon Cohen; Anthony L Ralph-Edwards

1998-01-01

36

Effects of 60-Heartz Electric and Magnetic Fields on Implanted Cardiac Pacemakers. Final Report.  

National Technical Information Service (NTIS)

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 si...

J. E. Bridges M. J. Frazier

1979-01-01

37

A stochastic network model of the interaction between cardiac rhythm and artificial pacemaker  

Microsoft Academic Search

In order to study heart-pacemaker interaction (HPI), a computer model of the cardiac conduction system has been developed which includes the effects of artificial pacemaker function and failure. The stochastic network model of cardiac conduction consists of five vertices, each representing a functional electrophysiologic element. Electrophysiologic multidimensional conditional probability functions determine the depolarization status of each vertex. The atrioventricular (AV)

S. E. Greenhut; J. M. Jenkins; R. S. MacDonald

1993-01-01

38

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

39

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

Microsoft Academic Search

The hazard of undetected cardiac pacemakers exploding in crematoria is well described. This short report describes the use of an affordable hand-held metal detector to detect cardiac pacemakers. Over the course of a year, the metal detector located 100% of cardiac pacemakers in a district general hospital mortuary. A simple model using pigskin and fat is also used to demonstrate

Jason Lyle Stone; John Williams; Lesley Fearn

2010-01-01

40

The effects of nuclear magnetic resonance on patients with cardiac pacemakers  

SciTech Connect

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

Pavlicek, W. (Cleveland Clinic Foundation, OH); Geisinger, M.; Castle, L.; Borkowski, G.P.; Meaney, T.F.; Bream, B.L.; Gallagher, J.H.

1983-04-01

41

Cardiac magnetic resonance in a patient with MRI-conditional pacemaker.  

PubMed

An implanted pacemaker is generally considered a contraindication for magnetic resonance imaging (MRI). The increasing number of indications for MRI and the rising prevalence of implanted cardiac pacemakers have prompted the recent development of MRI-conditional pacemaker systems. We present the case of a 68-year-old woman with left ventricular hypertrophy, hypertension, aortic valve stenosis and a family history of cardiac amyloidosis, who developed complete heart block. In view of the foreseeable need for cardiac MRI, an MRI-conditional dual chamber pacemaker was implanted. The MRI scan confirmed moderate left ventricular hypertrophy and aortic valve stenosis, and showed no delayed enhancement suggestive of amyloid heart disease. This case illustrates the feasibility of cardiac MRI in this setting and the usefulness of the recently introduced MRI-conditional pacemaker systems. PMID:23333214

Ferreira, António Miguel; Mendes, Lígia; Soares, Luís; da Graça Correia, Maria; Gil, Victor

2013-01-17

42

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

PubMed

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

Leitgeb, Norbert; Niedermayr, Florian; Neubauer, Robert

2012-06-01

43

Cardiac Pacemaker Infection: Surgical Management With and Without Extracorporeal Circulation  

Microsoft Academic Search

Background. Pacemaker infections are rare, but serious complications of pacemaker therapy. The generator pocket, the pacing leads, or both may be involved.Methods. We report on 12 patients with infected pacemaker systems. Four patients suffered from localized generator pocket infections, 6 had infected leads, and 2 patients had both. Pacemaker systems were completely removed in all patients. When the infection was

Markus J Wilhelm; Christof Schmid; Dieter Hammel; Sebastian Kerber; Heinz Michael Loick; Mathias Herrmann; Hans H Scheld

1997-01-01

44

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

45

Generic Environmental Statement of Routine Use of Plutonium-Powered Cardiac Pacemakers.  

National Technical Information Service (NTIS)

The Final Environmental Statement on Routine Use of Plutonium-Powered Cardiac Pacemakers (FES) was issued in July 1976. Supplement 1, prepared in 1978, updates the FES with respect to power sources for pacemakers. Particular attention is given to the non-...

1979-01-01

46

Permanent pacemaker implantation after cardiac transplantation: extra cost of a conservative policy  

Microsoft Academic Search

OBJECTIVE: To determine the costs of a change in permanent pacemaker implantation policy to later implantation (day 21+) after cardiac transplantation. DESIGN: Retrospective review of patient records including duration of temporary pacing, timed of permanent pacemaker implantation, and length of hospital stay for every patient surviving > or = 14 days from November 1990 to August 1995 (period 2) and

N. D. Holt; G. Parry; M. M. Tynan; J. H. Dark; J. M. McComb

1996-01-01

47

[Pacemaker and intra cardiac defibrillator lead extraction techniques].  

PubMed

Percutaneous Pace-maker and ICD lead extraction techniques has been developped: by superior approach using locking stylet and more and more efficient outher sheats (laser assisted); and also by femoral approach using double lasso catheters (Needle's eye snare). Indication range has increased and is not only reserved for lead infection. Because of scar tissue holding the lead and also the impact of the distal tip, those techniques are not simples. Extraction recommandations do advise those procedures to be performed by expert physicians, in cardiac surgery centers, where complications can be managed and reduced. The use of laser assisted outher sheats will make lead extraction easier and will reduce complication rate. Alternative procedure in case of failure with superior approach remain femoral approach. All those techniques give a success rate of about 98 % for percutaneous lead extraction in an expert center. PMID:15702909

Defaye, P; Dechaux, D; Machecourt, J

2005-01-01

48

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

49

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

50

Effects of magnetic resonance imaging on cardiac pacemakers and electrodes  

Microsoft Academic Search

In phantom studies we investigated the effects of magnetic resonance imaging (MRI) on pacemakers and electrodes. Twenty-five electrodes were exposed to MRI in a 1.5T scanner with continuous registration of the temperature at the electrode tip. Eleven pacemakers (five single chamber and six dual chamber) were exposed to MRI. Pacemaker output was monitored to detect malfunction in VOO\\/DOO and VVI\\/DDD

Stephan Achenbach; Werner Moshage; Björn Diem; Tobias Bieberle; Volker Schibgilla; Kurt Bachmann

1997-01-01

51

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

PubMed

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

Babouri, A; Hedjeidj, A; Guendouz, L

2009-01-06

52

Computed tomography in patients with cardiac pacemakers: difficulties and solutions.  

PubMed

The presence of cardiac pacemaker systems may significantly limit interpretation of multi-slice computed tomography (MSCT) images. In 80 patients (45 men; aged 69.5 ± 13.4) with previously implanted anti-arrhythmic devices, a 64-slice CT (Aquilion-64) was performed. In 61 patients (76.3%), ECG gating was used (coronaries visualization) and in 19 patients (23.7%) without ECG gating (not coronaries visualization). In all 19 patients without ECG gating MSCT images were diagnostic. In 37 (60.6%) patients of 61, there was no problem with gating process and image quality was diagnostic. In 24 (39.4%) with visible spikes in the ECG-gating group, there were difficulties in differentiating the R spike from an artificial spike (unipolar pacing) by MSCT software. In 15 patients (24.6%) after reprogramming, it was possible to obtain good quality images. In nine (14.7%) patients, it was not possible to reprogram devices due to old unipolar leads, but in two cases (3.3%), ECG gating was corrected manually and good image quality was obtained. In seven (11.5%) patients, it was not possible to perform ECG gating. The ECG gating process was identified as the main cause of the imaging problems. Bipolar leads working as bipolar pacing seem to be necessary to perform MSCT with ECG gating. A unipolar system lead may cause serious problems with reconstructions. PMID:21505855

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

2011-04-20

53

Tbx3 controls the sinoatrial node gene program and imposes pacemaker function on the atria  

PubMed Central

The sinoatrial node initiates the heartbeat and controls the rate and rhythm of contraction, thus serving as the pacemaker of the heart. Despite the crucial role of the sinoatrial node in heart function, the mechanisms that underlie its specification and formation are not known. Tbx3, a transcriptional repressor required for development of vertebrates, is expressed in the developing conduction system. Here we show that Tbx3 expression delineates the sinoatrial node region, which runs a gene expression program that is distinct from that of the bordering atrial cells. We found lineage segregation of Tbx3-negative atrial and Tbx3-positive sinoatrial node precursor cells as soon as cardiac cells turn on the atrial gene expression program. Tbx3 deficiency resulted in expansion of expression of the atrial gene program into the sinoatrial node domain, and partial loss of sinoatrial node-specific gene expression. Ectopic expression of Tbx3 in mice revealed that Tbx3 represses the atrial phenotype and imposes the pacemaker phenotype on the atria. The mice displayed arrhythmias and developed functional ectopic pacemakers. These data identify a Tbx3-dependent pathway for the specification and formation of the sinoatrial node, and show that Tbx3 regulates the pacemaker gene expression program and phenotype.

Hoogaars, Willem M.H.; Engel, Angela; Brons, Janynke F.; Verkerk, Arie O.; de Lange, Frederik J.; Wong, L.Y. Elaine; Bakker, Martijn L.; Clout, Danielle E.; Wakker, Vincent; Barnett, Phil; Ravesloot, Jan Hindrik; Moorman, Antoon F.M.; Verheijck, E. Etienne; Christoffels, Vincent M.

2007-01-01

54

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

2013-07-23

55

Update on cardiac pacemakers: description, complications, indications, and followup.  

PubMed

Great advances in pacemaker technology have produced devices capable of a vast array of physiologic adaptations formerly unimaginable, opening new possibilities in the pacemaker treatment of almost all rhythm disturbances. Nearly all units in use today are of the inhibited type, except for some antitachycardia applications. The AV-sequential mode (DVI) allows for preservation of AV synchrony, and the universal pacemaker (DDD) allows for a more physiologic response to a range of atrial rates. Programmability of numerous parameters has added a new dimension of adaptability to a variety of changing physiologic needs and pacemaker performance patterns, eliminating the need for surgical revision in many cases. The standard power source of today's pacemaker is the lithium chemistry cell, and the 5-year pacemaker is a reality, with 10 to 15 years of longevity distinctly possible in the near future. Almost all pacemakers use the transvenous route for access to the heart; new positive-fixation electrodes reduce displacement to a minimum; and new polyurethane or silicone-rubber leads have greatly simplified the techniques for implantation. Bipolar pacing systems are preferred, to avoid the oversensing of skeletal muscle interference--a problem that is especially important in triggered systems such as those used for antitachycardia applications. Threshold measurements are performed in millivolts at the time of implantation of most constant-voltage units, and current threshold measurements are useful for troubleshooting when failure to capture exists. Sensitivity parameters should be adjusted to sense the intracardiac signal; its amplitude should be determined in all cases, and measurement of the slew rate is useful when the amplitude is marginal. Recording of AV and VA conduction characteristics should be part of the routine implanting procedure, especially when simple blood pressure measurement during ventricular pacing indicates that this modality will be poorly tolerated and, therefore, implantation of a dual-chamber unit is contemplated. Different modalities of pacemaker malfunction have been reviewed, including the "cross-talk" phenomenon encountered with dual-chamber pacing. With the introduction of newer techniques, a host of pacemaker-mediated tachycardias have appeared, notably the "endless-loop" tachycardia of DDD pacemakers. This and other electrophysiologic phenomena of normal pacemaker function are bound to multiply as technology becomes more complex, but they should not be a problem if the programmable parameters are adapted to the electrophysiology of each particular patient.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:3915711

Medina, R; Michelson, E L

1985-01-01

56

Localization of natriuretic peptides in the cardiac pacemaker of Atlantic salmon (Salmo salar L.).  

PubMed

This study describes the location of the primary pacemaker at the sino-atrial (SA) junction and the localization of salmon cardiac peptide (sCP) and ventricular natriuretic peptide (VNP) in Atlantic salmon (Salmo salar L.). The pacemaker tissue appeared lightly stained and composed of: (1) wavy nerve bundles with oval elongated wavy appearing nuclei with pointed ends, (2) ganglion cells (12-22 ?m) with granular cytoplasm and (3) wide muscle fibers with large nuclei (modified cardiomyocytes) clearly distinguishing them from the other myocardial cells. Pacemaker tissue was further evaluated using immunohistochemical staining. Immunoreactivity of natriuretic peptides (sCP and VNP) antisera showed specific staining in pacemaker ganglion cells in addition to the cardiomyocytes. Positive staining with anti-CD3? antisera in the pacemaker ganglion cells is a novel finding in teleosts and is consistent with observations in mammals. In conclusion, the Atlantic salmon pacemaker was shown to be located at the SA node and to harbor sCP and VNP peptides, suggesting a possible neuromodulatory and/or neurotransmitter role for these cardiac hormones within the teleost heart. PMID:22385580

Yousaf, Muhammad N; Amin, Anil B; Koppang, Erling O; Vuolteenaho, Olli; Powell, Mark D

2012-03-03

57

Shox2 regulates the pacemaker gene program in embryoid bodies.  

PubMed

The pacemaker tissues of the heart are a complex set of specialized cells that initiate the rhythmic heartbeat. The sinoatrial node (SAN) serves as the primary pacemaker, whereas the atrioventricular node can serve as a subsidiary pacemaker in cases of SAN failure or block. The elucidation of genetic networks regulating the development of these tissues is crucial for understanding the mechanisms underlying arrhythmias and for the design of targeted therapies. Here we report temporal and spatial self-organized formation of the pacemaker and contracting tissues in three-dimensional aggregate cultures of mouse embryonic stem cells termed embryoid bodies (EBs). Using genetic marker expression and electrophysiological analyses we demonstrate that in EBs the pacemaker potential originates from a localized population of cells and propagates into the adjacent contracting region forming a functional syncytium. When Shox2, a major determinant of the SAN genetic pathway, was ablated we observed substantial slowing of spontaneous contraction rates and an altered gene expression pattern including downregulation of HCN4, Cx45, Tbx2, Tbx3, and bone morphogenetic protein 4 (BMP4); and upregulation of Cx40, Cx43, Nkx2.5, and Tbx5. This phenotype could be rescued by adding BMP4 to Shox2 knockout EBs in culture from days 6 to 16 of differentiation. When wild-type EBs were treated with Noggin, a potent BMP4 inhibitor, we observed a phenotype consistent with the Shox2 knockout EB. Altogether, we have generated a reproducible in vitro model that will be an invaluable tool for studying the molecular pathways regulating the development of cardiac pacemaker tissues. PMID:23767866

Hashem, Sherin I; Lam, May L; Mihardja, Shirley S; White, Steven M; Lee, Randall J; Claycomb, William C

2013-07-26

58

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

PubMed

Permanent magnets may interfere with the function of cardiac pacemakers and implantable cardioverter-defibrillators (ICDs). Neodymium-iron-boron (NdFeB) magnets have become widely available in recent years and are incorporated in various articles of daily life. We conducted an in-vitro study to evaluate the ability of NdFeB magnets for home and office use to cause interference with cardiac pacemakers and ICDs. The magnetic fields of ten NdFeB magnets of different size and shape were measured at increasing distances beginning from the surface until a field-strength (B-field) value of 0.5 mT was reached. Furthermore, for each magnet the distance was determined at which a sample pacemaker switched from magnet mode to normal mode. Depending on the size and remanence of individual magnets, a B-field value of 0.5 mT was found at distances ranging from 1.5 cm to 30 cm and a value of 1 mT at distances from 1 cm to 22 cm. The pacemaker behavior was influenced at distances from 1 cm to 24 cm. NdFeB magnets for home and office use may cause interference with cardiac pacemakers and ICDs at distances up to 24 centimeters. Patient education and product declarations should include information about the risk associated with these magnets. PMID:18334784

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

2008-01-01

59

[Lead fracture--a still frequent cardiac pacemaker complication?].  

PubMed

The frequency of pacemaker complications has decreased during later periods of observations. The rate of pacing lead fractures has been reported to amount to 6.2%. According to our experience and data based on 3607 pacemaker implantations for over 15 years this retrospective study examines the following parameters: patient's data, year of implantation, interval till fracture, implantation vena, localisation of the fracture and therapeutic measures. In 1% (36 cases) of our pacemaker patients repeating operations were necessary due to lead fractures. In electrodes implanted after 1977 no break could be observed. Tested material and production methods as well as save implantation modus, avoidance of bending, coiling with a short radius and also a tied fixation ligature, can improve the results. PMID:6495910

Jaschke, W; Hoellen, I

1984-01-01

60

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

NASA Astrophysics Data System (ADS)

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

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

61

Pacemakers (Beyond the Basics)  

MedlinePLUS

... for permanent cardiac pacing Infections involving cardiac implantable electronic devices Modes of cardiac pacing: Nomenclature and selection ... PI PICTURES Pacemaker photo PI INTRODUCTION Pacemakers are electronic devices that stimulate the heart with electrical impulses ...

62

Method to detect cardiac abnormalities based on electrocardiography and sinoatrial pacemaker model  

Microsoft Academic Search

In this paper, a new method for detecting cardiac abnormalities (bradycardia and tachycardia) is proposed. Based on the YNI (Yanagihara, Noma, and Irisawa) model to analyze the pole-zero characteristics of the phase error between abnormal electrocardiography (ECG) and entrained YNI-response, it develops a diagnostic pacemaker system that can replace multiple sensors. The work derives for the first time the thresholds

Wei Vivien Shi; Timothy N. Chang; MengChu Zhou

2010-01-01

63

Experimental estimation of EMI from cellular base-station antennas on implantable cardiac pacemakers  

Microsoft Academic Search

The impact of electromagnetic interference (EMI) from cellular base station (BS) antennas on implantable cardiac pacemakers is clarified in this article. The estimation of the impact is based on in vitro experiments that are conducted using simulated multicarrier and multicode signals, which are transmitted from actual BS antennas and dipole antennas as the radiation source of the BS antenna. Critical

Yoshiaki Tarusawa; Kohjiroh Ohshita; Yasunori Suzuki; Toshio Nojima; Takeshi Toyoshima

2005-01-01

64

The Microcomputer as an Adjunct in the Transtelephonic Monitoring of Cardiac Pacemakers  

PubMed Central

Transtelephonic monitoring of implanted cardiac pacemakers is an efficacious method for maximization of pulse generator life. Use of a microcomputer to analyze the resulting data has proven a reliable adjunct. A working, integrated system is discussed along with benefits both economic and medical.

Criscione, James R.

1984-01-01

65

[Effective intracavitary pacemaking for Taxus baccata-induced cardiac conduction defects and arrhythmias].  

PubMed

Case of suicidal intoxication following ingestion of approximately 120 leaves is presented. Cardiogenic shock, severe cardiac arrhythmias and conduction defects were observed in the course of intoxication. Authors believe that application of transient intracavitary pacemaking significantly contributed to patient recovery. PMID:17724890

?ukasik-G?ebocka, Magdalena; Sie?ko, Andrzej; Klimaszyk, Dorota; Ma?kowski, Wojciech

2007-01-01

66

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

67

[Verification of irradiation conditions of X-rays that influence implantable cardiac pacemakers].  

PubMed

Originally, it was thought that X-rays did not influence implantable cardiac pacemakers. In general, radiological technologists did not take proper care of these devises at the time of X-Ray examinations. However, 11 cases in which pacemakers malfunctioned (for example partial electrical reset) during CT examinations have been reported in recent years. At the time, we tended to attribute such problems to the peculiarities of multi-detector CT (MDCT). However, on logical grounds this explanation seemed weak. To better explain the problem, we attempted various tests in which pacemakers were exposed to CT and X-ray photography equipment. We analyzed some ECG results to clarify the matter and took measurements to examine these problems. PMID:18719296

Umezawa, Naoki; Hirose, Minoru; Shinbo, Toshihiro

2008-07-20

68

Test and Evaluation of the Hewlett-Packard CodeMaster 100 Cardiac Monitor/Pacemaker/Defibrillator System.  

National Technical Information Service (NTIS)

The CodeMaster 100 is a portable cardiac monitor, defibrillator and pacemaker that offers synchronized defibrillation, electrocardiogram monitoring, noninvasive temporary pacing and pulse oximetery (SpO2) capabilities. The CodeMaster receives power via a ...

E. W. Hade J. D. Hale

1997-01-01

69

Heart Rate Regulation by G Proteins Acting on the Cardiac Pacemaker Channel  

Microsoft Academic Search

Heart rate is determined by pacemaker currents, of which the most important is the hyperpolarization-activated current I_f. Heart rate and I_f are increased by beta-adrenergic agonists and decreased by muscarinic agonists released from cardiac sympathetic and vagal nerves, respectively. The hypothesis that the receptors for each agonist are directly coupled to I_f channels by G proteins was tested. Under substrate-free

A. Yatani; K. Okabe; J. Codina; L. Birnbaumer; A. M. Brown

1990-01-01

70

[Permanent cardiac stimulation in Spain. Survey of the Pacemaker Task Force].  

PubMed

The results of an investigation made at the request of the Pacemaker Working Group, of the Electrocardiology and Arrhythmias Section, are analysed in order to know the functional and instrumental state of permanent cardiac stimulation in Spain, in two fundamental aspects: A) Pacemakers (MP) implantation and B) their subsequent follow-up. The conclusions reached through these data collected by 86 centres from a total of 115 investigations were: A1) An average of 180 MP per million people are implanted in Spain, of which 48.5% were carried out by cardiac surgeons, 27.5% by cardiologists, 16.7% by intensivists and 7.1% by teams made up from several specialties. The implantation does not mean that the patient must be transferred out from his province of residence, except in certain areas (La Rioja, Palencia, etc.). A2) Bicameral stimulation was not used in one third of the centres questioned. A3) Material conditions for implantation are, in general, adequate. A4) Endocavitary implantation technique is used in 99% of cases, with venous approach through percutaneous puncture of subclavian vein in 37.3% of cases. A5) The professional group most recently incorporated into cardiac stimulation is that of intensivists. A6) The most limited diagnostic methods are electrophysiology and nuclear cardiac technique. B1) Uneven geographical distribution of pacemaker control units (UCM) was found. B2) The main hierarchy dependence of the UCMs belongs to Cardiology Units. B3) Proportion of specially dedicated UCMs and of in vitro study laboratories is scarce. B4) Important participation of pacemaker manufacturing companies in the implementation of UCMs is found. PMID:2813887

1989-01-01

71

Functional role of L-type Cav1.3 Ca2+ channels in cardiac pacemaker activity  

PubMed Central

The spontaneous activity of pacemaker cells in the sino-atrial node (SAN) controls the heart rhythm and rate under physiological conditions. Pacemaker activity in SAN cells is due to the presence of the diastolic depolarization, a slow depolarization phase that drives the membrane voltage from the end of an action potential to the threshold of a new action potential. SAN cells express a wide array of ionic channels, but we have limited knowledge about their functional role in pacemaker activity and we still do not know which channels play a prominent role in the generation of the diastolic depolarization. It is thus important to provide genetic evidence linking the activity of genes coding for ionic channels to specific alterations of pacemaker activity of SAN cells. Here, we show that target inactivation of the gene coding for ?1D (Cav1.3) Ca2+ channels in the mouse not only significantly slows pacemaker activity but also promotes spontaneous arrhythmia in SAN pacemaker cells. These alterations of pacemaker activity are linked to abolition of the major component of the L-type current (ICa,L) activating at negative voltages. Pharmacological analysis of ICa,L demonstrates that Cav1.3 gene inactivation specifically abolishes ICa,L in the voltage range corresponding to the diastolic depolarization. Taken together, our data demonstrate that Cav1.3 channels play a major role in the generation of cardiac pacemaker activity by contributing to diastolic depolarization in SAN pacemaker cells.

Mangoni, Matteo E.; Couette, Brigitte; Bourinet, Emmanuel; Platzer, Josef; Reimer, Daniel; Striessnig, Jorg; Nargeot, Joel

2003-01-01

72

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

2008-12-02

73

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

SciTech Connect

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

Ellis, V.J.

1991-11-01

74

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

PubMed

We have developed a bioinstrumentation course that emphasizes practical application of engineering and biological concepts by having students focus on the development of a single biomedical device: a cardiac pacemaker. In creating their benchtop pacemaker, students learn about and design sensing circuitry, data acquisition and processing code, control system algorithms, and stimulation electronics. They also gain an understanding of cardiac anatomy and electrophysiology. The separate elements of the pacemaker created throughout the semester will be repeatedly tested, re-designed, and integrated with one another, culminating in an emulated pacemaker whose efficacy will be tested on North American bullfrogs. It is hypothesized that the hands-on learning in this course, coupled with the practical application of concepts in the context of a single biomedical device, will enhance students' skills in bioinstrumentation design. PMID:24110396

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

2013-07-01

75

Programming an optimal atrioventricular interval in a dual chamber pacemaker regional population.  

PubMed

Background: Since the introduction of the dual chamber pacemaker (DDDR) in the early 1980s, researchers have repeatedly discussed and attempted to optimize the atrioventricular (AV) interval, in order to increase the cardiac performance of pacemaker patients. Nominal AV delay in a DDDR is not, by hemodynamics, the best option for the majority of patients with AV conduction disorders. Our research is suggesting a simplified approach to define an optimal AV delay in a DDDR pacemaker population on the use of the programming electrocardiogram (ECG) at follow-up.Methods: The study enrolled 55 consecutive patients (67.28 ± 1.03 years, 36 male) with an initial dual chamber pacemaker implanted for complete and second degree AV block between 2005-2010. Optimal AV delay was achieved by programming an additional delay of 95 ms, to the medium value of the interval between atrial pacing spike to the end of P wave or to the width of intrinsic P wave, on the ECG of the programming device. At discharge, shortly after the implant procedure, the patients were examined by Doppler echocardiography, during nominal and optimal AV delay pacing measuring systolic and diastolic left ventricular function parameters.Results: Compared with the nominal AV delay settings, the left ventricular end diastolic volume did not changed (from 112.3 ± 2.3 ml to 112.9 ± 2.3 ml), the end systolic volume decreased (from 59.8 ± 1.7 ml to 50.9 ± 1.3 ml, p<0.01) after adjusted the AV delay, followed by an increased left ventricle ejection fraction (from 61.07 ± 0.18 % to 65.46 ± 0.13 %, p<0.001) and isovolumic relaxation time decreased (from 102.7 ± 1.9 ms to 97 ± 2 ms, p<0.05). E wave velocity, A wave velocity and E/A ratio were not significantly changed.Conclusion: AV delay adjusted by programmer ECG in a follow-up session of an implantable device is a simple and useful method used in our laboratory as a resource for ventricular pacing optimization and hemodynamic improvement in patients with a dual chamber pacemaker (DDDR). PMID:22879840

Statescu, Cristian; Sascau, Radu A; Maciuc, Vasile; Arsenescu Georgescu, Catalina

2011-10-01

76

Cardiac resynchronisation therapy versus dual site right ventricular pacing in a patient with permanent pacemaker and congestive heart failure  

Microsoft Academic Search

A 46-year-old male patient who had long-term right ventricular (RV) pacing for symptomatic complete heart block, initially by an epicardial, later with an endocardial pacing lead at the RV apex, developed congestive heart failure (CHF) and chronic atrial fibrillation 7 years following the pacemaker implantation and was medically treated. During follow-up, his pacemaker was upgraded to a cardiac resynchronisation therapy

Oruganti Sai Satish; Kuan-Hung Yeh; Ming-Shien Wen; Chun-Chieh Wang

77

[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

78

Formal Development of a Cardiac Pacemaker: From Specification to Code  

Microsoft Academic Search

\\u000a 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.\\u000a Further practical result and analysis are also in the context

Artur Oliveira Gomes; Marcel Vinicius Medeiros Oliveira

2010-01-01

79

A model for predicting electromagnetic interference of implanted cardiac pacemakers by mobile telephones  

Microsoft Academic Search

A prediction of the electromagnetic interference (EMI) of pacemakers due to mobile phones is significant in improving the immunity of pacemakers. The Pacemaker Committee of Japan recently conducted immunity tests of pacemakers for mobile phones, and consequently concluded that the connector between the pacemaker housing and the lead wire of the electrode plays a major role for the EMI due

Jianqing Wang; Osamu Fujiwara; Toshio Nojima

2000-01-01

80

Pacemakers and Implantable Defibrillators  

MedlinePLUS

... arrhythmia is serious, you may need a cardiac pacemaker or an implantable cardioverter defibrillator (ICD). They are ... are implanted in your chest or abdomen. A pacemaker helps control abnormal heart rhythms. It uses electrical ...

81

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

82

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

PubMed

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

Shinbane, Jerold S; Colletti, Patrick M; Shellock, Frank G

2011-10-27

83

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

84

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

PubMed Central

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

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

2013-01-01

85

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

NASA Astrophysics Data System (ADS)

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

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

2004-03-01

86

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

SciTech Connect

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

Moss, A.J.; Carstensen, E.

1985-02-01

87

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

PubMed Central

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.

Quinn, T. Alexander; Kohl, Peter

2012-01-01

88

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

2012-08-21

89

Heart pacemaker  

MedlinePLUS

... of breath. Some, pacemakers can be used to stop a heart rate that is too fast ( tachycardia ) or that ... et al. ACC/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College ...

90

Radiation effect on implanted pacemakers  

SciTech Connect

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

Pourhamidi, A.H.

1983-10-01

91

The use of permanent pacemakers in the detection of cardiac arrhythmias  

Microsoft Academic Search

Aims To compare pacemaker telemetry with simultaneous Holter recordings in the diagnosis of atrial fibrillation and to evaluate the STOP-AF study telemetry criteria for the presence of atrial fibrillation.Methods and Results 18 consecutive patients enrolled in the STOP-AF study had simultaneous 24h Holter recordings and down-loaded pacemaker telemetry. There was good agreement on heart rate, but the STOP-AF pacemaker criteria

C. J. Plummer; S. Henderson; L. Gardener; J. M. McComb

2001-01-01

92

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

SciTech Connect

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

Fuerschbach, P.W.; Hinkley, D.A. [Sandia National Labs., Albuquerque, NM (United States)

1997-03-01

93

[Capsule Endoscopy in Patients with Cardiac Pacemakers and Implantable Cardioverter Defibrillators - Is the Formal Contraindication still Justified?].  

PubMed

Background and Aims: Capsule endoscopy is an established tool for investigation of the small intestine. Because of limited clinical experience in patients with cardiac devices the US Food and Drug Administration and the manufacturers recommend not to use capsule endoscopy in these patients.Methods: Studies investigating possible interference between small bowel capsule endoscopy and cardiac pacemakers and implanted cardioverters were analysed. For the review we considered studies published in English or German and indexed in PubMed (Medline) as well as relevant abstracts and technical data from the manufacturer.Results: In vitro and in vivo studies applying real capsules revealed no clinically relevant interference with pacemakers and implanted cardioverters. This evidence already has had an impact on clinical practice and recommendations of scientific societies. On the other hand wireless telemetry can interfere with CE video.Conclusion: According to present evidence, small bowel capsule endoscopy can be used in patients with pacemakers and implanted cardioverters after obtaining informed consent concerning the formal existence of contraindication. PMID:23955141

Bandorski, D; Stunder, D; Höltgen, R; Jakobs, R; Keuchel, M

2013-08-16

94

Adrenaline: Mechanism of Action on the Pacemaker Potential in Cardiac Purkinje Fibers  

Microsoft Academic Search

The pacemaker potential in Purkinje fibers is generated by a slow fall in potassium current which allows the inward background currents to depolarize the membrane. Adrenaline shifts the relation between activation of the potassium current and membrane potential in a depolarizing direction. Consequently, during the pacemaker potential, the potassium current falls more rapidly to lower values and the inward currents

O. Hauswirth; D. Noble; R. W. Tsien

1968-01-01

95

Adverse effects of direct current cardioversion on cardiac pacemakers and electrodes  

Microsoft Academic Search

Use of pacing in sick sinus syndrome and recent developments in pacemaker therapy for intermittent atrial fibrillation raise the question of whether external electrical cardioversion should be used for termination of atrial fibrillation. This paper analyzes three cases of pacemaker and\\/or electrode dysfunction appearing after direct current (DC) cardioversion for termination of atrial fibrillation. Despite similar conditions during cardioversion in

Christiane Waller; Frank Callies; Heiner Langenfeld

2004-01-01

96

A model of cardiac tissue as a conductive system with interacting pacemakers and refractory time  

Microsoft Academic Search

A model of the heart tissue as a conductive system with two interacting pacemakers and a refractory time, is proposed. In the parametric space of the model the phase locking areas are investigated in detail. Obtained results allow us to predict the behaviour of excitable systems with two pacemakers depending on the type and intensity of their interaction and the

Alexander Loskutov; Sergei Rybalko; Ekaterina Zhuchkova

2002-01-01

97

Factors associated with cardiac conduction disorders and permanent pacemaker implantation after percutaneous aortic valve implantation with the CoreValve prosthesis  

Microsoft Academic Search

Background Cardiac conduction disorders and requirement for permanent pacemaker implantation (PPI) are not uncommon after surgical aortic valve replacement and have important clinical implications. We aimed to investigate the incidence of cardiac conduction disorders after percutaneous aortic valve implantation (PAVI) and to identify possible clinical factors associated with their development. Methods We studied 34 patients (mean age 80 +\\/- 8

Jan Baan Jr.; Ze Yie Yong; Karel T. Koch; José P. S. Henriques; Berto J. Bouma; Marije M. Vis; Riccardo Cocchieri; Jan J. Piek

2010-01-01

98

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

99

Long-term follow-up of two infants with an implanted cardiac pacemaker.  

PubMed

The clinical course of two patients with congenital heart block who had pacemaker implantation at age 7 and 8 months, respectively, is reviewed. One patient at age 10 years has had nine pulse generators inserted; the other has had six implantations, the most recent a lithium iodine pacemaker, during 8 1/2 years of observation. Both patients have shown normal physical development and emotional maturation despite multiple hospitalizations and pacemaker replacements, thus demonstrating that electrical pacing, initiated in infancy, can be maintained through childhood without adverse effects. PMID:1199948

Griffiths, S P; Hayes, C J; Bowman, F O; Gersony, W M

1975-12-01

100

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

101

Reducing RF-related heating of cardiac pacemaker leads in MRI: implementation and experimental verification of practical design changes.  

PubMed

There are serious concerns regarding safety when performing magnetic resonance imaging in patients with implanted conductive medical devices, such as cardiac pacemakers, and associated leads, as severe incidents have occurred in the past. In this study, several approaches for altering an implant's lead design were systematically developed and evaluated to enhance the safety of implanted medical devices in a magnetic resonance imaging environment. The individual impact of each design change on radiofrequency heating was then systematically investigated in functional lead prototypes at 1.5 T. Radiofrequency-induced heating could be successfully reduced by three basic changes in conventional pacemaker lead design: (1) increasing the lead tip area, (2) increasing the lead conductor resistance, and (3) increasing outer lead insulation conductivity. The findings show that radiofrequency energy pickup in magnetic resonance imaging can be reduced and, therefore, patient safety can be improved with dedicated construction changes according to a "safe by design" strategy. Incorporation of the described alterations into implantable medical devices such as pacemaker leads can be used to help achieve favorable risk-benefit-ratios when performing magnetic resonance imaging in the respective patient group. PMID:22383393

Nordbeck, Peter; Fidler, Florian; Friedrich, Michael T; Weiss, Ingo; Warmuth, Marcus; Gensler, Daniel; Herold, Volker; Geistert, Wolfgang; Jakob, Peter M; Ertl, Georg; Ritter, Oliver; Ladd, Mark E; Bauer, Wolfgang R; Quick, Harald H

2012-03-01

102

The use of permanent pacemakers in the detection of cardiac arrhythmias  

Microsoft Academic Search

Aims To compare pacemaker telemetry with simultaneous Holter recordings in the diagnosis of atrial fibrillation and to evaluate the STOP-AF study telemetry criteria for the presence of atrial fibrillation. Methods and Results 18 consecutive patients enrolled in the STOP-AF study had simultaneous 24 h Holter record- ings and down-loaded pacemaker telemetry. There was good agreement on heart rate, but the

C. J. Plummer; S. Henderson; L. Gardener; J. M. McComb

103

Analysis of the coupling of electromagnetic interference to unipolar cardiac pacemakers  

Microsoft Academic Search

A theoretical analysis is developed to determine the behaviour of the unipolar pacemaker catheter as a receiving aerial. The\\u000a theory is used to predict the effect of parameters such as the frequency and the length of the catheter on the coupling of\\u000a electromagnetic interference to the pacemaker. The results are presented in terms of an equivalent circuit which is useful

G. S. Smith; J. C. Toler

1981-01-01

104

Novel Perspectives on Cardiac Pacemaker Regulation: Role of the Coupled Function of Sarcolemmal and Intracellular Proteins  

Microsoft Academic Search

\\u000a Recent experimental and theoretical studies demonstrate that the sinoatrial node cells (SANCs), the primary pacemaker cells\\u000a of heart, operate as a complex system of functionally coupled sarcolemmal and intracellular proteins. The proteins of this\\u000a system dynamically (beat-to-beat) interact throughout the entire pacemaker cycle via membrane voltage and local subsarcolemmal\\u000a Ca2+ changes. Furthermore, functions of the sarcolemmal (SL) electrogenic proteins and

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

105

A migrating pacemaker  

PubMed Central

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

Gale, C; Mulley, G

2005-01-01

106

A migrating pacemaker.  

PubMed

A deceased 79 year old man with a permanent cardiac pacemaker was due to be cremated, but the pacemaker generator was not detectable by palpation. A hand held metal detector to locate the device so that it could be extracted before cremation. PMID:15749800

Gale, C P; Mulley, G P

2005-03-01

107

[Sport for pacemaker patients].  

PubMed

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

Israel, C W

2012-06-01

108

Mechanisms of Beat-to-Beat Regulation of Cardiac Pacemaker Cell Function by Ca(2+) 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

109

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

NASA Astrophysics Data System (ADS)

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

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

2009-02-01

110

[Exploration of a third degree atrioventricular block by standard echocardiography, tissue Doppler imaging, and treatment with a cardiac pacemaker in a German wire-haired pointer].  

PubMed

A nine-year-old intact male Drathaar was evaluated for syncope and extreme weakness, and was found to have a third degree atrioventricular (AV) block. As there were no biochemic, serologic, organic (thoracic radiographs, abdominal echography, standard and tissue Doppler echocardiographies) and histologic (interventricular septum biopsy) anomalies, the dog was treated with a permanently implanted cardiac pacemaker. PMID:14994485

Nicolle, A; Borenstein, N; Tessier Vetzel, D; Rouby, M; Behr, L; Pouchelon, J L; Chetboul, V

2004-02-01

111

The “Funny” Pacemaker Current  

Microsoft Academic Search

\\u000a Cellular and molecular mechanisms underlying cardiac pacemaking have long been the object of intense investigation, and several\\u000a issues concerning the exact role of individual processes involved in this important function are still not fully resolved.\\u000a Since its original discovery over 30 years ago, the “funny” (I\\u000a f) current of cardiac pacemaker cells has been the focus of a keen interest

Andrea Barbuti; Annalisa Bucchi; Raffaella Milanesi; Georgia Bottelli; Alessia Crespi; Dario DiFrancesco

112

Model of Cardiac Tissue as a conductive System with Interacting pacemakers and Refractory Time  

Microsoft Academic Search

A model of the heart tissue as a conductive system with two interacting pace- makers and a refractory time, is proposed. In the parametric space of the model the phase locking areas are investigated in detail. Obtained results allow us to predict the behaviour of excitable systems with two pacemakers depending on the type and intensity of their interaction and

Alexander Loskutov; Sergei Rybalko; Ekaterina Zhuchkova

2004-01-01

113

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

SciTech Connect

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

Not Available

1981-05-01

114

Shox2 is essential for the differentiation of cardiac pacemaker cells by repressing Nkx2-5  

PubMed Central

The pacemaker is composed of specialized cardiomyocytes located within the sinoatrial node (SAN), and is responsible for originating and regulating the heart beat. Recent advances towards understanding the SAN development have been made on the genetic control and gene interaction within this structure. Here we report that the Shox2 homeodomain transcription factor is restrictedly expressed in the sinus venosus region including the SAN and the sinus valves during embryonic heart development. Shox2 null mutation results in embryonic lethality due to cardiovascular defects, including an abnormal low heart beat rate (bradycardia) and severely hypoplastic SAN and sinus valves attributed to a significantly decreased level of cell proliferation. Genetically, the lack of Tbx3 and Hcn4 expression, along with ectopic activation of Nppa, Cx40, and Nkx2-5 in the Shox2?/? SAN region, indicates a failure in SAN differentiation. Furthermore, Shox2 overexpression in Xenopus embryos results in extensive repression of Nkx2-5 in the developing heart, leading to a reduced cardiac field and aberrant heart formation. Reporter gene expression assays provide additional evidence for the repression of Nkx2-5 promoter activity by Shox2. Taken together our results demonstrate that Shox2 plays an essential role in the SAN and pacemaker development by controlling a genetic cascade through the repression of Nkx2-5.

Espinoza-Lewis, Ramon A.; Yu, Ling; He, Fenglei; Liu, Hongbing; Tang, Ruhang; Shi, Jiangli; Sun, Xiaoxiao; Martin, James F.; Wang, Dazhi; Yang, Jing; Chen, YiPing

2009-01-01

115

Electromagnetic interference in a cardiac pacemaker during cauterization with the coagulating, not cutting mode.  

PubMed

Electromagnetic interference in pacemakers has almost always been reported in association with the cutting mode of monopolar electrocautery and rarely in association with the coagulation mode. We report a case of electrocautery-induced electromagnetic interference with a DDDR pacemaker (dual-chamber paced, dual-chamber sensed, dual response to sensing, and rate modulated) in the coagulating and not cutting mode during a spine procedure. We also discuss the factors affecting intraoperative electromagnetic interference. A 74-year-old man experienced intraoperative electromagnetic interference that resulted in asystole caused by surgical electrocautery in the coagulation mode while the electrodispersive pad was placed at different locations and distances from the operating site (This electromagnetic interference did not occur during the use of the cutting mode). However, because of careful management, the outcome was favorable. Clinicians should be aware that the coagulation mode of electrocautery can cause electromagnetic interference and hemodynamic instability. Heightened vigilance and preparedness can ensure a favorable outcome. PMID:22096289

Abdelmalak, Basem; Jagannathan, Narasimhan; Arain, Faisal D; Cymbor, Susan; McLain, Robert; Tetzlaff, John E

2011-10-01

116

[Effects of antihypertensive drugs with different mechanism of action on cardiac hemodynamics in patients with artificial pacemaker].  

PubMed

Cardiohemodynamic effects of obsidan, nifedipin, captopril and prasosine were compared when the drugs were given in a 4-week course regarding circulation type and stimulation regime to 74 patients with artificial pacemaker suffering from mild or moderate essential hypertension. A peculiar action of obsidan, nifedipin and prasosine in cardiac pacing found at echocardiography is explained by the absence of frequency-dependent (chronotropic) cardiohemodynamic effects. Obsidan lowered blood pressure most effectively in hyperkinetic circulation. Nifedipine, captopril and prasosine were more potent in eu- and hypokinetic circulation. Reduction of arterial pressure by the above peripheral vasodilators in patients with hyperkinetic circulation results from a fall of total peripheral vascular resistance initially elevated by 16.5%, on the average. In isolated ventricular stimulation (regime VVI) vs atrial one (AAI regime) hypotensive action of the above drugs was more potent, but side effects were more frequent. PMID:11220897

Iskenderov, B G; Latyshev, D S

2000-01-01

117

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

Microsoft Academic Search

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

Luksha

1980-01-01

118

Low frequency magnetic emissions and resulting induced voltages in a pacemaker by iPod portable music players  

Microsoft Academic Search

BACKGROUND: Recently, malfunctioning of a cardiac pacemaker electromagnetic, caused by electromagnetic interference (EMI) by fields emitted by personal portable music players was highly publicized around the world. A clinical study of one patient was performed and two types of interference were observed when the clinicians placed a pacemaker programming head and an iPod were placed adjacent to the patient's implanted

Howard Bassen

2008-01-01

119

Perirenal space implantation of permanent cardiac pacemakers in infants and small children.  

PubMed

Permanent pacemakers were implanted in 40 children aged one day to 17 years. A new technique, necessitating thoracotomy and lumbotomy, is described briefly. Indications were surgical block in 22 (55%) and congenital block in 18 (45%) patients. Five of 40 (12.5%) died. Reoperation was required 4 times: for electrode problems (3), and wound problem (one). No late infection or wire fractures were noted. The time paced ranged from 7 days to 37 months. All of these patients received lithium units. PMID:6190244

Hafez, A; Conso, J F; Belhaj, M; Planche, C; Binet, J P

1983-04-01

120

Pacemakers and Implantable Cardiac Defibrillators: Software Radio Attacks and Zero-Power Defenses  

Microsoft Academic Search

Abstract—Our study analyzes,the security and,privacy,prop- erties of an implantable,cardioverter,defibrillator (ICD). Intro- duced to the U.S. market in 2003, this model of ICD includes pacemaker,technology,and is designed,to communicate,wirelessly with a nearby,external programmer,in the 175 kHz frequency range. After partially reverse-engineering the ICD’s communi- cations protocol with an oscilloscope and a software radio, we implemented,several software,radio-based attacks,that could compromise,patient safety and,patient privacy.

Daniel Halperin; Thomas S. Heydt-benjamin; Benjamin Ransford; Shane S. Clark; Will Morgan; Kevin Fu; Tadayoshi Kohno; William H. Maisel

2008-01-01

121

Evidence dromyosuppressin acts at posterior and anterior pacemakers to decrease the fast and the slow cardiac activity in the blowfly Protophormia terraenovae  

Microsoft Academic Search

The molecular complexity of the simple blowfly heart makes it an attractive preparation to delineate cardiovascular mechanisms. Blowfly cardiac activity consists of a fast, high-frequency signal phase alternating with a slow, low-frequency signal phase triggered by pacemakers located in the posterior abdominal heart and anterior thoracocephalic aorta, respectively. Mechanisms underlying FMRFamide-related peptides (FaRPs) effects on heart contractions are not well

Anna Maria Angioy; Patrizia Muroni; Iole Tomassini Barbarossa; Jennifer McCormick; Ruthann Nichols

2007-01-01

122

Development of a Genetically Engineered Cardiac Pacemaker: Insights from Dynamic Action Potential Clamp Experiments  

Microsoft Academic Search

In this chapter, we briefly review the use of dynamic clamp in cardiac cellular electrophysiology and present novel results\\u000a obtained with the ‘dynamic action potential clamp’ (dAPC) technique. This is a technique that we recently developed to study\\u000a the effects of long-QT syndrome-related ion channel mutations by effectively replacing the associated native ionic current\\u000a of a cardiac myocyte with wild-type

Arie O. Verkerk; Jan G. Zegers; Antoni C. G. Ginneken; Ronald Wilders

123

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

SciTech Connect

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

Sung, Wonmo; Kim, Siyong; Kim, Jung-in; Lee, Jae-gi; Shin, Young-Joo; Jung, Jae-Yong; Ye, Sung-Joon [Interdisciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-799, South Korea and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul 110-744 (Korea, Republic of); Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida 32224 (United States); Interdisciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-799, South Korea and Department of Radiation Oncology, Kangbuk Samsung Medical Center, Seoul 110-746 (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul 110-744, South Korea and Department of Biomedical Radiation Sciences, Seoul National University, Seoul 151-742 (Korea, Republic of); Department of Radiation Oncology, Sanggye Paik Hospital, Inje University, Seoul 139-707 (Korea, Republic of); Interdisciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul 110-744 (Korea, Republic of); Department of Biomedical Radiation Sciences, Seoul National University, Seoul 151-742 (Korea, Republic of); Department of Radiation Oncology, Seoul National University, Seoul 110-799 (Korea, Republic of) and Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270 (Korea, Republic of)

2012-10-15

124

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

125

Predictive factors for pacemaker implantation in patients receiving an implantable loop recorder for syncope remained unexplained after an extensive cardiac and neurological workup.  

PubMed

BACKGROUND: Several previous implantable loop recorder (ILR) studies have shown bradyarrhythmic events requiring a pacemaker implantation in a significant proportion of patients with unexplained syncope (US). The aim of this observational, two-centre, study was to identify the predictive factors for pacemaker implantation in a population of patients receiving an ILR for US with suspected arrhythmic aetiology. METHODS: Fifty-six patients (mean age 68years, 61% male) with a history of US and negative cardiac and neurological workup, who underwent ILR implantation, were enrolled. After the implantation, a follow-up visit was undertaken after symptomatic events or every 3months in asymptomatic subjects. The end-point of the study was the detection of a bradyarrhythmia (with or without a syncopal recurrence) requiring pacemaker implantation. RESULTS: After a median ILR observation of 22months, a clinically significant bradyarrhythmia was detected in 11 patients (20%), of which 9 cases related to syncopal relapses. In the multivariable analysis, three independent predictive factors for pacemaker implantation were identified: an age >75years (odd ratio [OR]: 29.9; p=0.035); a history of trauma secondary to syncope (OR: 26.8; p=0.039); and the detection of periods of asymptomatic bradycardia, not sufficient to explain the mechanism of syncope, during conventional ECG monitoring (through 24h Holter or in hospital telemetry), performed before ILR implantation (OR: 24.7; p=0.045). CONCLUSIONS: An advanced age, a history of trauma secondary to syncope, and the detection of periods of asymptomatic bradycardia during conventional ECG monitoring were independent predictive factors for bradyarrhythmias requiring pacemaker implantation in patients receiving an ILR for US. PMID:23701932

Palmisano, Pietro; Accogli, Michele; Zaccaria, Maria; Luzzi, Giovanni; Nacci, Frida; Anaclerio, Matteo; Favale, Stefano

2013-05-20

126

[Defecation syncope following pacemaker implantation].  

PubMed

A case of syncope is reported, where hemodynamic responses compatible with pacemaker syndrome occurred during defecation. A 73 year old female received a VVI pacemaker for complete heart block. Subsequently she sustained repeated episodes of defecation syncope. Hemodynamic investigations revealed an abnormal blood pressure drop occurring at the overshoot phase of the Valsalva maneuver in association with alternation of sinus and pacemaker rhythm. This modified Valsalva response in the presence of contributing factors, such as hypovolemia and nitroglycerin therapy manifested as defecation syncope. The abnormal condition was treated by eliminating the contributing factors, and by programming a low pacemaker frequency, thus precluding sinus-pacemaker alterations. PMID:9064621

Rudas, L; Kardos, A; Halmai, L; Török, T; Pap, I; Hegedüs, Z

1997-01-12

127

Pacemaker current changes during intracellular pH transients in sheep cardiac Purkinje fibres  

Microsoft Academic Search

1.Intracellular acidosis, at constant extracellular pH, hyperpolarizes the resting potential and reduces the diastolic depolarization rate of cardiac Purkinje fibres. With alkaline pHi, the fibre depolarizes and spontaneous firing is observed.2.Intracellular pH transients induced either by superfusion with Tyrode buffered with 5% CO2\\/23 mM HCO3- or 16% CO2\\/61 mM HCO3-, or with solutions containing weak undissociated acids, transiently shifted the

P. P. Van Bogaert

1985-01-01

128

Development of the pacemaker tissues of the heart  

Microsoft Academic Search

Pacemaker and conduction system myocytes play crucial roles in initiating and regulating the contraction of the cardiac chambers. Genetic defects, acquired diseases, and aging cause dysfunction of the pacemaker and conduction tissues, emphasizing the clinical necessity to understand the molecular and cellular mechanisms of their development and homeostasis. Although all cardiac myocytes of the developing heart initially possess pacemaker properties,

V. M. Christoffels; G. J. Smits; A. Kispert; A. F. M. Moorman

2010-01-01

129

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

2013-03-16

130

Evidence dromyosuppressin acts at posterior and anterior pacemakers to decrease the fast and the slow cardiac activity in the blowfly Protophormia terraenovae.  

PubMed

The molecular complexity of the simple blowfly heart makes it an attractive preparation to delineate cardiovascular mechanisms. Blowfly cardiac activity consists of a fast, high-frequency signal phase alternating with a slow, low-frequency signal phase triggered by pacemakers located in the posterior abdominal heart and anterior thoracocephalic aorta, respectively. Mechanisms underlying FMRFamide-related peptides (FaRPs) effects on heart contractions are not well understood. Here, we report antisera generated to a FaRP, dromyosuppressin (DMS, TDVDHVFLRFamide), recognized neuronal processes that innervated the blowfly Protophormia terraenovae heart and aorta. Dromyosuppressin caused a reversible cardiac arrest. High- and low-frequency signals were abolished after which they resumed; however, the concentration-dependent resumption of the fast phase differed from the slow phase. Dromyosuppressin decreased the frequency of cardiac activity in a dose-dependent manner with threshold values between 5 fM and 0.5 fM (fast phase), and 0.5 fM and 0.1 fM (slow phase). Dromyosuppressin structure-activity relationship (SAR) for the decrease of the fast-phase frequency was not the same as the SAR for the decrease of the slow-phase frequency. The alanyl-substituted analog TDVDHVFLAFamide ([Ala9] DMS) was inactive on the fast phase, but active on the slow phase, a novel finding. FaRPs including myosuppressins are reported to require the C-terminal RFamide for activity. Our data are consistent with the conclusions DMS acts on posterior and anterior cardiac tissue to play a role in regulating the fast and slow phases of cardiac activity, respectively, and ligand-receptor binding requirements of the abdominal and thoracocephalic pacemakers are different. PMID:17141921

Angioy, Anna Maria; Muroni, Patrizia; Barbarossa, Iole Tomassini; McCormick, Jennifer; Nichols, Ruthann

2006-12-04

131

Evidence dromyosuppressin acts at posterior and anterior pacemakers to decrease the fast and the slow cardiac activity in the blowfly Protophormia terraenovae  

PubMed Central

The molecular complexity of the simple blowfly heart makes it an attractive preparation to delineate cardiovascular mechanisms. Blowfly cardiac activity consists of a fast, high frequency signal phase alternating with a slow, low frequency signal phase triggered by pacemakers located in the posterior abdominal heart and anterior thoracocephalic aorta, respectively. Mechanisms underlying FMRFamide-related peptides (FaRPs) effects on heart contractions are not well understood. Here, we report antisera generated to a FaRP, dromyosuppressin (DMS, TDVDHVFLRFamide), recognized neuronal processes that innervated the blowfly Protophormia terraenovae heart and aorta. Dromyosuppressin caused a reversible cardiac arrest. High and low frequency signals were abolished after which they resumed; however, the concentration dependent resumption of the fast phase differed from the slow phase. Dromyosuppressin decreased the frequency of cardiac activity in a dose dependent manner with threshold values between 5 fM and 0.5 fM (fast phase) and 0.5 fM and 0.1 fM (slow phase). Dromyosuppressin structure-activity relationship (SAR) for the decrease of the fast phase frequency was not the same as the SAR for the decrease of the slow phase frequency. The alanyl-substituted analog TDVDHVFLAFamide ([Ala9] DMS) was inactive on the fast phase, but active on the slow phase, a novel finding. FaRPs including myosuppressins are reported to require the C-terminal RFamide for activity. Our data are consistent with the conclusions DMS acts on posterior and anterior cardiac tissue to play a role in regulating the fast and slow phases of cardiac activity, respectively, and ligand-receptor binding requirements of the abdominal and thoracocephalic pacemakers are different.

Angioy, Anna Maria; Muroni, Patrizia; Barbarossa, Iole Tomassini; McCormick, Jennifer; Nichols, Ruthann

2009-01-01

132

[Management of patients after pacemaker implanation (author's transl)].  

PubMed

Although pacemaker therapy is characterized by a high degree of reliability, follow-up of pacemaker patients is necessary to provide early detection of pacemaker failure and optimal setting of programable pacemakers as well as to render adequate treatment of underlying disease. The most common cause of pacemaker failure is battery depletion. In spite of the available data on the mean life-expectancy of the various batteries, the individual time of depletion cannot be predicted with accuracy. Furthermore, a defect in the electronic circuitry and/or electrode may still be rarely encountered even though technical standards are high and, occasionally, threshold elevation or lead dislocation may occur in spite of conscientious implantation technique. For patients with programable pacemakers, follow-up monitoring also enables adjustment for optimal pacemaker function. Thus, through lowering of the current or narrowing of the pulse width, the life of the battery can be prolonged or, on incrementation of these 2 parameters, an increasing threshold can be compensated for within certain limits. More important, however, is the possibility of inductive pacemaker rate changes through external programing to yield the most favorable pulse interval with respect to the underlying disease. Since, in addition to impairment of the cardiac conduction system, other disease processes are frequently presented--approximately one in three patients has coronary artery disease and almost half of the patients have congestive heart failure--follow-up visits not only serve the purpose of monitoring pacemaker function but also provide an opportunity to insure an optimal clinical condition of the patient. Accurate interpretation of pacemaker function prerequisites knowledge of the type of stimulation (fixed rate, synchronized, hysteresis, magnet rate, interference frequencies), of the battery (mercury-zinc, lihium, nickel-cadmium, isotope), of the programability (rate, current, pulse width) as well as the location of impulse capture and detection and through ascertainment of secured position of the lead and generator. While the pacemaker rate enables interpretation of the state of charge of the battery, evaluation of capture and tracing threshold permit assessment of the presence of a threshold elevation, lead dislocation, an electrode fracture or a defect in the electronic circuity. Stimulation of extracardiac muscle areas may be indicative of improper positioning and inadequate isolation of the generator, lead dislocation or lead perforation. PMID:554856

Petri, H; Rudolph, W

1978-12-01

133

[A cardiac embolic stroke due to malposition of the pacemaker lead in the left ventricle. A case report].  

PubMed

Misplacement of a permanent pacemaker lead has been described in several locations but rarely in the left ventricle. Less commonly, as described in our report, malposition may occur when the lead perforates the interatrial septum and extends across the left atrium and through the mitral valve into the left ventricle. The actual incidence of this pacemaker complication is unknown. Consequences may include perforation and systemic or cerebral thromboembolic events. We report the case of a patient with unintentionally misplaced left heart pacemaker lead admitted for neurological symptoms consistent with embolic stroke. The patient was on aspirin when symptoms occurred. The lead misplacement was not recognized at the time of implantation. Pacing threshold was normal. A 12-lead electrocardiogram showed right bundle branch block configuration paced complexes. By two-dimensional and transesophageal echocardiography, the pacemaker lead was carefully evaluated. The pacemaker lead crossed the interatrial septum, the left atrium, the mitral valve to be implanted in the left ventricular endocardium. To avoid the risk of future embolization, it was felt that the lead should be removed and right ventricular pacing established, once anticoagulation treatment was initiated. Successful percutaneous lead replacement was accomplished without sequelae. Measures to avoid lead misplacement are suggested. PMID:10832129

Agnelli, D; Ferrari, A; Saltafossi, D; Falcone, C

2000-01-01

134

Cardiac Resynchronization Therapy Using a Dual Chamber Pacemaker in Patients with Severe Left Ventricular Dysfunction and a Left Bundle Branch Block  

PubMed Central

Through the use of a dual chamber (DDD) pacemaker, we achieved a cardiac resynchronization effect in a 51-year-old female patient who was transferred to our hospital from another hospital for an operation for three-vessel coronary artery disease. Her electrocardiogram showed a left bundle branch block (LBBB) and a prolonged QRS interval of 166 milliseconds. Severe left ventricle (LV) dysfunction was diagnosed via echocardiography. Coronary artery bypass grafting (CABG) was then performed. In order to accelerate left atrial activation and reduce the conduction defect, DDD pacing using right atrial and left and right ventricular pacing wires was initiated postoperatively. The cardiac output was measured immediately, and one and twelve hours after arrival in the intensive care unit. The cardiac output changed from 2.8, 2.4, and 3.6 L/min without pacing to 3.5, 3.4, and 3.5 L/min on initiation of pacing. The biventricular synchronization using DDD pacing was turned off 18 hours after surgery. She was transferred to a general ward with a cardiac output of 3.9 L/min. In patients with coronary artery disease, severe LV dysfunction, and LBBB, cardiac resynchronization therapy can be achieved through DDD pacing after CABG.

Jung, Jae Jun; Kim, In Sook; Jeong, Jae-Han; Jeong, Dong Seop

2013-01-01

135

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

136

Varying the heart rate response to dynamic exercise in pacemaker-dependent subjects: effects on cardiac output and cerebral blood velocity.  

PubMed

Cerebral blood flow increases upon the transition from rest to moderate exercise, but becomes affected when the ability to raise CO (cardiac output) is limited. HR (heart rate) is considered to contribute significantly to the increase in CO in the early stages of dynamic exercise. The aim of the present study was to test whether manipulation of the HR response in patients dependent on permanent rate-responsive ventricular pacing contributes to the increase in CO, MCA V(mean) [mean MCA (middle cerebral artery) velocity] and work capacity during exercise. The effect of setting the pacemaker to DSS ('default' sensor setting) compared with OSS ('optimized' sensor setting) on blood pressure, CO, SV (stroke volume) and MCA V(mean) was evaluated during ergometry cycling. From rest to exercise at 75 W, the rise in HR in OSS [from 73 (65-87) to 116 (73-152) beats/min; P<0.05] compared with DSS [70 (60-76) to 97 (67-117) beats/min; P<0.05] was larger. There was an increase in SV during exercise with DSS, but not with OSS, such that, at all workloads, SVs were greater during DSS than OSS. The slope of the HR-CO relationship was larger with DSS than OSS (P<0.05). From rest to exercise, MCA V(sys) (systolic MCA velocity) increased in OSS and DSS, and MCA V(dias) (diastolic MCA velocity) was reduced with DSS. No changes were observed in MCA V(mean). Manipulation of the pacemaker setting had no effect on the maximal workload [133 (100-225) W in OSS compared with 129 (75-200) W in DSS]. The results indicate that, in pacemaker-dependent subjects with complete heart block and preserved myocardial function, enhancing the HR response to exercise neither augments CO by a proportional offset of the exercise-induced increase in SV nor improves cerebral perfusion. PMID:16038616

Bogert, Lysander W J; Erol-Yilmaz, Ayten; Tukkie, Raymond; Van Lieshout, Johannes J

2005-12-01

137

Lithium pacemaker batteries - an overview  

SciTech Connect

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

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

1980-01-01

138

The nuclear pacemaker: Is renewed interest warranted  

SciTech Connect

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

Parsonnet, V.; Berstein, A.D.; Perry, G.Y. (Newark Beth Israel Medical Center, NJ (USA))

1990-10-01

139

Integration of Nutrition Education into a Multidisciplinary Cardiac Rehabilitation Program  

Microsoft Academic Search

The multidisciplinary Cardiac Rehabilitation Program (CRP) at Wilford Hall Medical Center was redesigned to improve both efficiency and effectiveness of services offered to patients following recovery from either myocardial infarction or cardiac bypass surgery. Services were redesigned to provide a “one stop shop” approach for minimizing inconvenience to patients and for achieving the CRP's goals of increasing functional cardiac capacity,

J. L. Weinstein; S. A. Jarvis; W. A. Gradwell; G. Wadsack; A. L. Peterson; P. Hoofman; S. Clark; S. McCann

1999-01-01

140

Left ventricular dyssynchrony predicts benefit of cardiac resynchronization therapy in patients with end-stage heart failure before pacemaker implantation  

Microsoft Academic Search

We evaluated patients with end-stage heart failure who have a high likelihood of response to cardiac resynchronization therapy (biventricular pacing). It appears that 20% of patients do not respond to this expensive therapy despite the use of selection criteria (dilated cardiomyopathy, heart failure, New York Heart Association class II or IV, left ventricular ejection fraction 120 ms). The presence of

Jeroen J. Bax; Thomas H. Marwick; Sander G. Molhoek; Gabe B. Bleeker; Lieselot van Erven; Eric Boersma; Paul Steendijk; Ernst E. van der Wall; Martin J. Schalij

2003-01-01

141

Influence of a Cardiac Rehabilitation Program on the cardiovascular, psychological, and social functioning of cardiac patients  

Microsoft Academic Search

Twenty-eight male cardiac patients who had either experienced myocardial infarction or undergone coronary bypass surgery were assigned to a treatment condition and participated in a 3-month, exercise-based Cardiac Rehabilitation Program, whereas 20 other cardiac patients were assigned to a routine-care condition and did not participate in the rehabilitation program. Cardiovascular, psychological, and psychosocial functioning were assessed before treatment or routine

Susan Roviaro; David S. Holmes; R. David Holmsten

1984-01-01

142

Behavior change outcomes in an outpatient cardiac rehabilitation program  

Microsoft Academic Search

Objective To evaluate the effectiveness of nutrition education within an outpatient cardiac rehabilitation program.Design Subjects were assigned, according to participation in cardiac rehabilitation programs in two community hospitals within an integrated healthcare system, to either a treatment (n=54), or a control group (n=50).Subjects\\/setting One hundred four men and women, age range 35 to 85 years, participating in a 6-week cardiac

Maureen T. Timin; Kevin V. Shores; Marla Reicks

2002-01-01

143

Optogenetic Control of Cardiac Function  

Microsoft Academic Search

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

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

2010-01-01

144

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

145

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

146

Catheter ablation of ventriculoatrial conduction in the treatment of pacemaker-mediated tachycardia.  

PubMed

Pacemaker generator reprogramming does not always present an adequate solution to the problem of pacemaker-mediated tachycardia. A case is described where direct current shock catheter ablation of ventriculoatrial conduction prevented pacemaker-mediated tachycardia and allowed optimal dual chamber pacemaker programming. PMID:1715061

Pitney, M; Davis, M

1991-06-01

147

A single pacemaker cell model based on the phase response curve  

Microsoft Academic Search

A single pacemaker cell model and its response to repetitive external depolarization stimulations is described in this paper. This model is a simple\\u000a model based on the two most important functional properties of the cardiac pacemaker cells. The first property is the intrinsic pacemaker cycle length, which is an `internal' parameter of the cell, describing the most important feature of

Sarit Abramovich-Sivan; Solange Akselrod

1998-01-01

148

Fatal outcome in a pacemaker-dependent patient.  

PubMed

The recent advisory of Medtronic Sprint Fidelis leads has resulted in significant controversy over proper management of patients. The current manufacture's guidelines recommend programming specific device alerts with close follow-up and implantable cardioverter-defibrillator lead replacement in patients with evidence of breach in lead integrity. Recently, several studies have identified significant limitations in this method of surveillance. We report the case of a pacemaker-dependent patient with an ischemic cardiomyopathy, who presented with cardiac arrest and evidence of fracture of the pace/sense portion of a Sprint Fidelis lead during postmortem interrogation. Likely mechanisms leading to his ultimate demise are discussed. PMID:19335869

Undavia, Manish; Fischer, Avi; Mehta, Davendra

2009-04-01

149

Gene therapy: Biological pacemaker created by gene transfer  

NASA Astrophysics Data System (ADS)

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

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

2002-09-01

150

A pacemaker cell pair model based on the phase response curve  

Microsoft Academic Search

.  \\u000a A pacemaker cell pair model and the dynamic interaction between the two pacemaker cells is described in this paper. It is an extension of our single\\u000a pacemaker cell model, in which we studied its response to repetitive external depolarization stimulations. This model is a\\u000a simple model based on the two most important functional properties of the cardiac pacemaker cells:

Sarit Abramovich-Sivan; Solange Akselrod

1998-01-01

151

CHEMICAL PACEMAKERS  

PubMed Central

1. Iron spicules found in the brains of general paretic patients are formed from endogenous brain iron normally present in another form. This supports our earlier view that the µ value of 16,000 obtained in advanced paretics for alpha brain wave frequencies as a measure of cortical respiration comes about from the slowing of an iron catalyzed link in cortical respiration such as would result from the reduction of available cytochrome and its oxidase, thus making this step a chemical pacemaker. 2. To test the basic theory of chemical pacemakers, a study was made of the succinate-fumarate enzyme system containing succino-dehydrogenase and cytochrome-cytochrome oxidase acting sequentially. 3. The µ value for the unpoisoned system is 11,200 ± 200 calories. 4. According to theory, the addition of a critical amount of cyanide known to be a specific poison of the cytochrome-cytochrome oxidase system (and not of the dehydrogenase) should shift the µ cleanly to 16,000 calories, and it does. 5. According to theory, selenite, a specific poison for the dehydrogenase, should stop all respiration without shifting the µ. This also is found to be the case. 6. The theory also predicts that if the µ is shifted from 11,000 ± to 16,000 ± by cyanide, the subsequent addition of a critical amount of selenite should shift the µ back again to 11,000 ± calories, and this is found to occur. 7. It is concluded that approximately 11,000 calories is the energy of activation of the succino-dehydrogenase-catalyzed step and 16,000 calories is that for the cytochrome-cytochrome oxidase-catalyzed step. These two values are encountered more frequently than any others in physiological systems. It is to be recalled that a shift of µ for alpha brain wave frequencies from 11,000 to 16,000 calories occurs in the course of advancing syphilitic brain infection and is accompanied by a change in form of brain iron.

Hadidian, Zareh; Hoagland, Hudson

1939-01-01

152

NRSF regulates the fetal cardiac gene program and maintains normal cardiac structure and function  

PubMed Central

Reactivation of the fetal cardiac gene program is a characteristic feature of hypertrophied and failing hearts that correlates with impaired cardiac function and poor prognosis. However, the mechanism governing the reversible expression of fetal cardiac genes remains unresolved. Here we show that neuron-restrictive silencer factor (NRSF), a transcriptional repressor, selectively regulates expression of multiple fetal cardiac genes, including those for atrial natriuretic peptide, brain natriuretic peptide and ?-skeletal actin, and plays a role in molecular pathways leading to the re-expression of those genes in ventricular myocytes. Moreover, transgenic mice expressing a dominant-negative mutant of NRSF in their hearts exhibit dilated cardiomyopathy, high susceptibility to arrhythmias and sudden death. We demonstrate that genes encoding two ion channels that carry the fetal cardiac currents If and ICa,T, which are induced in these mice and are potentially responsible for both the cardiac dysfunction and the arrhythmogenesis, are regulated by NRSF. Our results indicate NRSF to be a key transcriptional regulator of the fetal cardiac gene program and suggest an important role for NRSF in maintaining normal cardiac structure and function.

Kuwahara, Koichiro; Saito, Yoshihiko; Takano, Makoto; Arai, Yuji; Yasuno, Shinji; Nakagawa, Yasuaki; Takahashi, Nobuki; Adachi, Yuichiro; Takemura, Genzo; Horie, Minoru; Miyamoto, Yoshihiro; Morisaki, Takayuki; Kuratomi, Shinobu; Noma, Akinori; Fujiwara, Hisayoshi; Yoshimasa, Yasunao; Kinoshita, Hideyuki; Kawakami, Rika; Kishimoto, Ichiro; Nakanishi, Michio; Usami, Satoru; Saito, Yoshitomo; Harada, Masaki; Nakao, Kazuwa

2003-01-01

153

21 CFR 870.3600 - External pacemaker pulse generator.  

Code of Federal Regulations, 2010 CFR

...pacing sytem until a permanent pacemaker can be implanted, or to control irregular heartbeats in patients following cardiac surgery or a myocardial infarction. The device may have adjustments for impulse strength, duration, R-wave...

2010-04-01

154

21 CFR 870.3600 - External pacemaker pulse generator.  

Code of Federal Regulations, 2013 CFR

...permanent pacemaker can be implanted, or to control irregular heartbeats in patients following cardiac surgery or a myocardial infarction. The device may have adjustments for impulse strength, duration, R-wave sensitivity, and other pacing...

2013-04-01

155

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

156

Scedosporium apiospermum pacemaker endocarditis  

Microsoft Academic Search

A patient developed a fungal pacemaker infection with Scedosporium apiospermum following a series of pacemaker manipulations. Despite percutaneous removal of the pacemaker system and subsequent operative extraction of the atrial thrombus, his course was complicated by persistent sepsis, pulmonary septic emboli and bilateral frontal lobe infarction, following which treatment was withdrawn.

Hong Foo; Sze-Yuan Ooi; Robert Giles; Philip Jones

2009-01-01

157

Common indications of permanent pacemaker insertion.  

PubMed

Approximately one million people in the US have permanent pacemakers. These patients are usually seen in general practice and referred to a cardiologist. Therefore, it is important for the internists and hospitalists to be aware of the indications and complications of cardiac pacing. PMID:18681108

Ahmed, Syed Mashood; Ansari, Muhammad Jaffer

2008-01-01

158

Nonlinearity of Cardiac Pacemaker Electrodes  

Microsoft Academic Search

Nonlinear properties of electrodes immersed in saline were studied in the time domain and frequency domain. Three electrode materials were tested: platinum-iridium, Elgiloy, and stainless steel. For time domain measurements, current pulses of 1.0 to 2.0 ms duration and varying amplitudes were applied to the electrodes. Frequency domain measurements of polarization impedance were made with an impedance bridge, utilizing sinusoidal

Dov Jaron; Stanley A. Briller; Herman P. Schwan; David B. Geselowitz

1969-01-01

159

Pacemaker and Internal Cardioverter-Defibrillator Therapies  

Microsoft Academic Search

Cardiac rhythm management devices (CRMD) have evolved significantly since the late 1950s, when the first pacemakers (PM) were\\u000a implanted [1]. However, transcutaneous electrical cardiac stimulation was used to treat symptomatic advanced second-degree or third-degree\\u000a atrioventricular (AV) heart block (Stokes-Adams attacks) in the 1920s [1, 2]. The first implantable devices were asynchronous ventricular PM (VOO1) for patients with Stokes-Adams attacks, and

J. L. Atlee

160

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

161

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

SciTech Connect

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

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

1985-05-01

162

Dynamic action potential clamp as a powerful tool in the development of a gene-based bio-pacemaker  

Microsoft Academic Search

The development of a genetically engineered ‘biological pacemaker’, or ‘bio-pacemaker’, is a rapidly emerging field of research. One of the approaches in this field is to turn intrinsically quiescent myocardial cells, i.e., atrial or ventricular cells, into pacemaker cells by making them express the cardiac hyperpolarization-activated ‘pacemaker current’ If (known in neurophysiology as Ih), which is encoded by the hyperpolarization-activated

Arie O. Verkerk; Jan G. Zegers; Antoni C. G. van Ginneken; Ronald Wilders

2008-01-01

163

Bradycardia and Permanent Pacemakers  

Microsoft Academic Search

The investigation and management of bradycardia is an increasingly complex topic, but with the development of pacemakers there are few areas of medicine that offer such substantial improvements in patients' quality of life. About 400,000 pacemakers are implanted worldwide per year; about 270 are implanted per million population in the UK, 370 per million in Europe as a whole and

Vince Paul

2002-01-01

164

Pacemaker implantation after congenital heart surgery: risk and prognosis in a population-based follow-up study  

Microsoft Academic Search

Objective: Although earlier a feared complication of congenital cardiac surgery, the incidence of heart-block and sinus node dysfunction has been lowered to 1–4% due to improved surgical techniques and better anatomical understanding of the cardiac conduction system. Development of feasible pacemaker technologies has further lowered mortality and morbidity. However, pacemaker implantation in paediatric patients is in itself associated with significant

Morten Smerup; Thomas Hjertholm; Søren P. Johnsen; Anders K. Pedersen; Peter S. Hansen; Peter T. Mortensen; Ole K. Hansen; Vibeke Hjortdal

2005-01-01

165

Pacemaker/defibrillator evaluation at Los Angeles County Department of Coroner*.  

PubMed

Pacemakers and implantable cardioverter-defibrillators (ICDs) are implanted medical devices for the treatment of cardiac arrhythmias. These devices are now commonly encountered in the postmortem situation. The Los Angeles County Department of the Coroner uses the services of a cardiac electrophysiology consultant to interrogate pacemakers and ICDs, producing a detailed picture of the cardiac events recorded by the device. We have used this method to evaluate 20 cases where the ICD or pacemaker provided significant information. We report four forensic cases to illustrate the different applications of pacemaker interrogation and its contribution in forensic investigation. This technique was used to establish identification of the decedent, to determine the cause and time of death, and to determine whether device malfunction could have played a role in the death. We conclude that detailed evaluation of the pacemaker or ICD in selected cases may provide essential information to the forensic pathologist. PMID:18637876

Saint-Martin, Pauline; Rogers, Christopher; Muto, Joseph; Boyle, Noel G; Rieders, Daniel; Sathyavagiswaran, Lakshmanan

2008-07-14

166

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

167

Cardiac pacing in children.  

PubMed

Advances in pacemaker technology over the last 25 years have made cardiac pacing in infants and children a safe and practical therapy. Some of the technical challenges encountered with the first permanent pacemaker implantation in children during the early 1960s have been solved with miniaturized generators, lithium batteries, noninvasive programmability, and improved placement techniques. This chapter reports common causes of bradydysrhythmias in children, reviews the indications for permanent pacemaker implantation in children, describes current pacing systems appropriate for children, and identifies nursing implications and potential pacemaker complications unique to children. PMID:1995011

Lawrence, P A

1991-02-01

168

Electrode for Artificial Pacemaker.  

National Technical Information Service (NTIS)

The patent discloses an electrode for implantation in the heart to control atrio-ventricular block by artificial pacemaker including plural electrically conductive wires grouped in a bundle with spring metal arcuate prongs formed on one end thereof. A she...

G. M. Thomas J. W. Boretos D. C. Syracuse J. A. Clark A. J. Vita

1977-01-01

169

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

170

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

PubMed

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. PMID:22852824

Keshtgar, Mohammed Rs; Eaton, David J; Reynolds, Claire; Pigott, Katharine; Davidson, Tim; Gauter-Fleckenstein, Benjamin; Wenz, Frederik

2012-08-01

171

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

172

Rehabilitating elderly cardiac patients.  

PubMed Central

The aging cardiovascular system undergoes many anatomic and physiologic changes. Increased vascular resistance, myocardial "stiffness," abnormalities of rhythmicity of the sinoatrial node, irregular cardiac rhythms, and alterations in heart rate and blood pressure responses are all seen more frequently in older patients. These changes are likely to impair these patients' ability to make the rapid adjustments necessary to maintain cardiac output during exercise and activity. When cardiovascular disease processes are superimposed on the "normal" concomitants of aging, greater alterations in hemodynamic response to exercise activity are noted than usually occur in younger cardiac patients. Exercise testing of older cardiac patients is safe and is usually needed to prescribe an appropriate intensity of exercise activity. The choice of the exercise protocol, the timing of the exercise test in relation to taking prescribed cardiac medication, the choice of exercise equipment, and special considerations for devices such as pacemakers and automatic implantable cardiodefibrillators must be considered before the exercise test is done. Many of these factors and the presence of either silent or overt cardiac symptoms or untoward hemodynamic events will also affect the exercise prescription. Elderly patients usually show substantial functional improvement when participating in a cardiac rehabilitation program and comply well with prescribed exercise. Early educational intervention may be crucial to reducing disability in these patients.

Anderson, J. M.

1991-01-01

173

Clinical assessment of pacemaker power sources  

SciTech Connect

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

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

1980-01-01

174

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

175

Radiation safety program for the cardiac catheterization laboratory.  

PubMed

The Society of Cardiovascular Angiography and Interventions present a practical approach to assist cardiac catheterization laboratories in establishing a radiation safety program. The importance of this program is emphasized by the appropriate concerns for the increasing use of ionizing radiation in medical imaging, and its potential adverse effects. An overview of the assessment of radiation dose is provided with a review of basic terminology for dose management. The components of a radiation safety program include essential personnel, radiation monitoring, protective shielding, imaging equipment, and training/education. A procedure based review of radiation dose management is described including pre-procedure, procedure and post-procedure best practice recommendations. Specific radiation safety considerations are discussed including women and fluoroscopic procedures as well as patients with congenital and structural heart disease. PMID:21254324

Chambers, Charles E; Fetterly, Kenneth A; Holzer, Ralf; Lin, Pei-Jan Paul; Blankenship, James C; Balter, Stephen; Laskey, Warren K

2011-01-19

176

Mesenchymal stem cells as a gene delivery system to create biological pacemaker cells in vitro.  

PubMed

Pacemaker cells differ from common cardiomyocytes due to the presence of a spontaneous depolarization process during the diastolic phase of the cardiac cycle. This is due to hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which are responsible for providing an inward current. Genetically engineered mesenchymal stem cells (MSCs) were transfected with hHCN4 genes using lentiviral transfection, and their potential use as biological pacemaker cells was investigated. In addition to expressing an anticipated high level of the hHCN4 gene, MSCs transfected with hHCN4 genes also expressed characteristic hHCN4 protein, a cardiac pacemaker-like current and were capable of increasing the spontaneous beating rate of co-cultured cardiac myocytes. Control MSCs did not exert these effects. It is hypothesized that genetically engineered MSCs transfected with hHCN4 genes by lentiviral transfection can be modified to be cardiac pacemaker cells in vitro. PMID:18831900

Yang, X-J; Zhou, Y-F; Li, H-X; Han, L-H; Jiang, W-P

177

Acute and chronic effects of cardiac resynchronization in patients developing heart failure with long-term pacemaker therapy for acquired complete atrioventricular block  

Microsoft Academic Search

Aims We assessed the effects of cardiac re-synchronization therapy (CRT) in patients who developed otherwise unexplained heart failure (HF) during right ventricular apical (RVA)-pacing for acquired com- plete atrioventricular block (CAVB). Methods and results Eighteen consecutive CAVB patients with HF during RVA-pacing were assessed with haemodynamic studies immediately and 12 months after CRT-upgrade. Ten patients had idiopathic CAVB and 13

Masayuki Shimano; Yukiomi Tsuji; Yukihiko Yoshida; Yasuya Inden; Naoya Tsuboi; Teruo Itoh; Hirohiko Suzuki; Takashi Muramatsu; Taro Okada; Shuji Harata; Takumi Yamada; Haruo Hirayama; Toyoaki Murohara

178

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

PubMed

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

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

2013-09-01

179

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

Code of Federal Regulations, 2010 CFR

...rehabilitation program services for beneficiaries who have experienced one or more of the following: (i) An acute myocardial infarction within the preceding 12 months; (ii) A coronary artery bypass surgery; (iii) Current stable...

2010-10-01

180

Pacemaker infective endocarditis  

Microsoft Academic Search

We identified 33 patients with definite pacemaker endocarditis—that is, with direct evidence of infective endocarditis, based on surgery or autopsy histologic findings of or bacteriologic findings (Gram stain or culture) of valvular vegetation or electrode-tip wire vegetation. Most of the patients (75%) were ?60 years of age (mean 66 ± 3; range 21 to 86). Pouch hematoma or inflammation was

Patrice Cacoub; Pascal Leprince; Patrick Nataf; Pierre Hausfater; Richard Dorent; Bertrand Wechsler; Valéria Bors; Alain Pavie; Jean Charles Piette; Iradj Gandjbakhch

1998-01-01

181

Small artery compliance improves with comprehensive cardiac rehabilitation program in deconditioned men with coronary artery disease  

Microsoft Academic Search

Objective: Small artery compliance (SAC) is an earlier and more reliable predictor of cardiovascular events. We examined the effects of a comprehensive Cardiac Rehabilitation Program on SAC in deconditioned patients with coronary artery disease.Methods: Patients with recent history of coronary artery disease and referred to the Cardiac Rehabilitation Program were enrolled in the study. The patients underwent 8–12 weeks of

Mohammad A. Rafey; Jonathan P. Greenblatt; Patricia Brownstein; Lorene Bruno; Robert A. Phillips

2003-01-01

182

Early evaluation of a rechargeable pacemaker system.  

PubMed

A rechargeable demand pulse generator for permanent transvenous cardiac pacing was evaluated in 66 patients. During a cumulative follow-up period of 895 patient months there was no instance of failure of either the pulse generator or of the recharging circuit. Acceptance of the recharging concept was high, there being only one patient in whom it was necessary to replace the rechargeable generator because of inability to master the recharging technique. The early findings indicate that with proper patient selection the rechargeable pulse generator promises to be an important contribution to pacemaker therapy. PMID:978092

Stertzer, S H; DePasquale, N P; Bruno, M S; Cohn, L J

1976-01-01

183

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

Microsoft Academic Search

Staphylococcus aureus is a leading cause of septicaemia and infective endocarditis. The overall incidence of staphylococcal bacteraemia is increasing, contributing to 16% of all hospital-acquired bacteraemias. The use of cardiac pacemakers has revolutionized the management of rhythm disturbances, yet this has also resulted in a group of patients at risk of pacemaker lead endocarditis and seeding in the range of

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

2003-01-01

184

21 CFR 870.3700 - Pacemaker programmers.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Pacemaker programmers. 870.3700 Section 870...Cardiovascular Prosthetic Devices § 870.3700 Pacemaker programmers. (a) Identification. A pacemaker programmer is a device used to...

2013-04-01

185

21 CFR 870.3670 - Pacemaker charger.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Pacemaker charger. 870.3670 Section 870.3670...Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker charger is a device used...

2013-04-01

186

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

PubMed

Detailed analysis of stored electrograms is essential for the interpretation of arrhythmias, programming changes, and optimization of the medical therapy in patients with implanted pacemakers and defibrillators. The physician who cares for patients with implantable electrical devices has to be able to understand the detection and treatment algorithms of those devices. Biotronik pacemakers of newer generations are capable of storing intracardiac electrograms. Earlier devices store up to 12 electrograms of 10 s duration after certain trigger events, like atrial tachycardia or high ventricular rates. Cardiac resynchronization systems can store electrograms after patient activation with magnets in addition to the above mentioned trigger-activated electrograms. Defibrillators store intracardiac electrograms during tachycardia episodes with near-field and far-field electrograms of the right ventricular lead in addition to the markers in single and dual chamber defibrillators (in addition to an atrial electrogram) and near field electrograms of the atrial, the right, and the left ventricular electrode in addition to the markers in resynchronization systems. Each channel has a maximum storing capacity of 32 min. If there are more episodes than storing capacity, electrograms of older episodes will be overwritten, but if the newer episodes are all classified as supraventricular, the last two ventricular episodes (VT or VF) will remain in the episode memory. This article describes stored electrograms, detection, and treatment algorithms of implantable cardiac devices manufactured by Biotronik. PMID:20309671

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

2010-03-01

187

Clinical trials with one type of lithium pacemaker generator.  

PubMed

Cardiac Pacemakers, Inc. (CPI) solid-state, lithium-powered pulse generators were implanted in 100 patients by one surgeon in a twenty-eight-month period. Eleven CPI pacer generators were replaced, none due to pacer failure. Ninety-nine percent of the patients were followed for a total of 1,397.55 patient-months; 12 patients died, but no deaths appeared to be pacemaker related. The average age of the patients at the time of implantation was 72.8 years. If the warranty period of six years is achieved, the number of pacemaker generator changes required by many of the patients in this group could foreseeably be zero. PMID:655749

Trapp, W G; Taunton, C A

1978-06-01

188

[The termination of auricular flutter by noninvasive programmed electrical stimulation using a permanent AAI-mode pacemaker].  

PubMed

We describe a case of a 15-year-old boy with an atrial septal defect who three years after the direct closure of the defect presented with atrial flutter type I according to Wells's classification. He was then electrically cardioverted but presented immediately sinus bradycardia and a ventricular escape rhythm that required epicardial pacing (Intermedics 292-03 DASH) in the AAI mode. We report here the successful termination of a new episode of atrial flutter into sinus rhythm with a noninvasive programmed stimulation using his previously implanted pacing system. PMID:8215704

Saucedo, J; Iturralde, P; Attie, F; Colín, L; Kershenovich, S; González Hermosillo, J A

189

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

PubMed Central

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 necropsy or from the certified cause of death. Demographic data, including the time of implant and reasons for implantation, were checked. The pacemakers were analysed in terms of battery status, program, and output under a standard 470 ohm load. RESULTS: 69 patients were studied. Average age at death was 78 and 80 years for men and women, respectively. The average duration since pacemaker implantation was 46 months. Eleven patients had necropsies, showing that three died from ischaemic heart disease, six from cardiomyopathy, one from an aortic aneurysm, and one from disseminated neoplasia. From the necropsy results and death certificates, the distribution of causes of death in the group as a whole were ischaemic heart disease (21), cardiomyopathy (8), cerebrovascular disease (11), neoplasia (11), chest infection/chronic obstructive airways disease (8), and other causes (10). In all cases the pacemaker box function was within normal limits. CONCLUSIONS: Neither primary nor secondary pacemaker dysfunction was found. The study highlights the impact of arrhythmias in cardiomyopathy, and raises questions about the true role of ischaemic heart disease in these pacemaker requiring patients. The relatively short gap between pacemaker implantation and death requires further study. Images

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

1999-01-01

190

Pacemaker Interferentie Meetopstelling (System for Measuring Pacemaker Interference).  

National Technical Information Service (NTIS)

As a result of a growing number of questions from users of pacemakers and from suppliers as well as from users of potential sources of interference, research was conducted on problems of interference in pacemakers. A number of sources of interference (hig...

C. van Nimwegen J. Boter G. E. P. M. van Venrooij

1981-01-01

191

Developing a Culturally Based Cardiac Rehabilitation Program: The HELA Study  

PubMed Central

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

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

2012-01-01

192

Safety considerations during cardiac and pulmonary rehabilitation program.  

PubMed

As more and more patients with cardiac and pulmonary diseases are living longer lives, the need for cardio-pulmonary rehabilitation continues to grow. The goal of this article is to provide clinicians of rehabilitation medicine with an overview of the safety concerns and strategies to implement in the rehabilitation of patients with cardiac and/or pulmonary disorder. PMID:22537704

Suler, Yelena; Dinescu, Laurentiu Iulius

2012-04-05

193

Runaway in a modern "soft top" pacemaker.  

PubMed

Although runaway pacemaker was a relatively common occurrence, modern pacemaker design has made it extremely rare. We report a case occurring with a modern "soft-top" pacemaker that resulted from a loss of hermeticity. Although the different treatment options are discussed, the definitive maneuvre is explantation of the faulty pacemakers PMID:9392822

Betts, T R; Thomas, R D; Hubbard, W N

1997-11-01

194

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

195

Review Article Gene Therapy in Cardiac Arrhythmias  

Microsoft Academic Search

Gene therapy has progressed from a dream to a bedside reality in quite a few human diseases. From its first application in adenosine deaminase deficiency, through the years, its application has evolved to vascular angiogenesis and cardiac arrhythmias. Gene based biological pacemakers using viral vectors or mesenchymal cells tested in animal models hold much promise. Induction of pacemaker activity within

Johnson Francis

196

[Dynamics of the excitable media with two interacting pacemakers].  

PubMed

A general model of the nonlinear interaction of two impulse systems was developed, which describes some types of cardiac arrhythmias. Phase locking phenomena were studied with consideration for refractoriness time. The phenomena of tongue splitting and the overlapping of the major synchronization regions were revealed. The results obtained make it possible to predict the behavior of excitable systems with two pacemakers depending on the type and intensity of their interaction and on the initial phase difference. PMID:12397963

Loskutov, A Iu; Rybalko, S D; Zhuchkova, E A

197

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

198

Sinus venosus atrial septal defect: a rare cause of misplacement of pacemaker leads.  

PubMed

Routine implantation of pacemakers and implantable cardioverter defibrillators is not commonly associated with complications. However, in some cases we see misplacement of pacemaker leads which is most often related to the presence of underlying cardiac anomalies. We report the case of misplacement of a pacemaker lead into the left ventricle of a 56-year-old patient paced in VVI/R mode and with a tined type pacemaker lead because of a symptomatic complete atrioventricular block. Electrocardiogram showed a pacemaker-generated rhythm with a right bundle branch block pattern. Chest X-ray showed the pacemaker lead located relatively high in relation to the diaphragm. Echocardiography visualized the pacemaker lead in the left heart chambers (atrium and ventricle), hence confirming its aberrant course. Further, the defect causing its passage to the left heart chambers was a sinus venosus atrial septal defect. The patient reported no complication related to the misplacement of the lead. After a brief period of oral anticoagulation, the lead was inserted into the right ventricle by percutaneous technique. PMID:23847433

Bodian, Malick; Aw, Fatou; Bamba, Mouhamadou Ndiaye; Kane, Adama; Jobe, Modou; Tabane, Alioune; Mbaye, Alassane; Sarr, Simon Antoine; Diao, Maboury; Sarr, Moustapha; Bâ, Serigne Abdou

2013-07-05

199

Establishing a cardiac MRI program: problems, pitfalls, expectations.  

PubMed

Magnetic resonance imaging (MRI) has been used to evaluate the cardiovascular system for almost 2 decades. Although vascular applications have been robust and steadily improving for many years, the utility of MRI for clinical cardiac imaging has been limited. However, recent advances in hardware technology and pulse sequence design have led to substantial improvements in image quality, while reducing scan times to clinically reasonable durations. Pulse sequences using electrocardiographic gating and k-space segmentation have made it possible to obtain high-contrast, high-resolution images of the beating heart within single breath-holds. These images in turn have provided unprecedented visualization of myocardial morphology and function. Because of these developments, cardiac MRI (CMR) has made rapid and dramatic inroads into the clinical arena. Currently, the primary limitations to routine clinical application are hardware availability, clinical acceptance, politics, examination cost, and not least of all physician education. As these limitations are overcome or made more manageable, the clinical use of CMR will grow, potentially without bound. Combined with steady hardware development and an ever-growing armamentarium of pulse sequences, MRI may ultimately become the modality of choice for cardiac imaging. Because cardiac imaging is relatively unknown territory for most radiologists and because the high-end equipment has until now been sparsely available, CMR has been largely limited to major medical centers. However, if sufficient interest is present and resources are appropriately allocated, CMR can be successfully implemented in community imaging practices. PMID:17411921

Atalay, Michael K

2005-09-01

200

Pacemaker endocarditis: an important clinical entity  

PubMed Central

Pacemaker endocarditis remains a rare but potentially life threatening complication of pacemaker implantation. This case illustrates a rare cause of pacemaker endocarditis, Serratia marcescens, the management difficulties that can be faced with such organisms, and the potential indolent nature of pacemaker lead associated endocarditis. A review of the current data for pacemaker endocarditis management suggests that treatment with antimicrobials alone is unlikely to be curative and explantation of the device is recommended in all cases of confirmed pacemaker endocarditis (by echocardiography, in correlation with the patient’s clinical condition and inflammatory markers).

De Silva, Kalpa; Fife, Amanda; Murgatroyd, Francis; Gall, Nicholas

2009-01-01

201

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

SciTech Connect

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

Sager, D.P.

1987-03-01

202

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

203

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  

PubMed Central

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 clinicians with frequent and complete access to stored data in pacemakers. In addition to monitoring device function, remote monitors may be a helpful tool in assisting physicians in the management of common arrhythmia disorders. Methods The Pacemaker REmote Follow-up Evaluation and Review (PREFER) trial is a prospective, randomized, parallel, unblinded, multicenter, open label clinical trial to determine the utility of remote pacemaker interrogation in the earlier diagnosis of clinically actionable events compared to the existing practice of transtelephonic monitoring. There have been 980 patients enrolled and randomized to receive pacemaker follow up with either remote interrogation using the Medtronic CareLink® Network (CareLink) versus the conventional method of transtelephonic monitoring (TTM) in addition to periodic in-person interrogation and programming evaluations. The purpose of this manuscript is to describe the design of the PREFER trial. The results, to be presented separately, will characterize the number of clinically actionable events as a result of pacemaker follow-up using remote interrogation instead of TTM. Trial registration ClinicalTrials.gov: NCT00294645.

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

2008-01-01

204

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

PubMed

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

Yamagishi, H; Hirose, E

1997-09-01

205

New Method Cuts Radiation During Pacemaker Procedure  

MedlinePLUS

... sharing features on this page, please enable JavaScript. New Method Cuts Radiation During Pacemaker Procedure: Study Electromagnetic ... X-Rays WEDNESDAY, Sept. 4 (HealthDay News) -- A new way of implanting pacemakers cuts radiation exposure for ...

206

Cardiac catheterization and angiography. Third edition  

SciTech Connect

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

Grossman, W.

1986-01-01

207

Pacemaker-associated Bacillus cereus endocarditis.  

PubMed

We report the case of a pacemaker-associated Bacillus cereus endocarditis in a nonimmunocompromised patient. Antibiotic treatment was ineffective, and the pacemaker had to be removed. B. cereus was cultured from several blood samples and from the pacemaker electrodes. This case underlines the contribution of the rpoB gene for Bacillus species determination. PMID:22959918

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

2012-09-07

208

Design and testing of a percutaneously implantable fetal pacemaker.  

PubMed

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

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

2012-08-02

209

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

210

Fifty years of pacemaker advancements.  

PubMed

A 1957 power blackout in Minnesota prompted C. Walton Lillehei, MD, a pioneer in open heart surgery, to ask Earl Bakken, the co-founder of Medtronic, Inc., to create a battery-operated pacemaker for pediatric patients. That conversation led to the development of the first external battery-operated pacemaker. That first bulky device is far removed from the tiny implantable computers available to heart patients today. Now, the size of two silver dollars stacked on top of one another, a pacemaker is prescribed for a person whose heart beats too slowly or pauses irregularly. Slightly larger devices have more recently evolved from pacing and regulating the heartbeat to being able to provide therapeutic high voltage shocks when needed to stop runaway fast heart rates, recording heart activity, and other physiologic functions, even resynchronizing the heart's chambers-all while providing information on the patient's condition and device performance to the doctor remotely or in the office. PMID:20559931

Steinhaus, David

2008-11-04

211

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

PubMed Central

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

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

2013-01-01

212

Mammalian circannual pacemakers.  

PubMed

Circannual clocks drive rhythms in reproduction and many other seasonal characteristics but the underlying control of these long-term oscillators remains a mystery. Now, we propose that circannual timing involves mechanisms that are integral to the ontogenetic life-history programme where annual transitions are generated by cell birth, death and tissue regeneration throughout the life cycle--the histogenesis hypothesis. The intrinsic cycle is then timed by cues from the environment. The concept is that in specific sites in the brain, pituitary and peripheral tissues, residual populations of progenitor cells (adult stem cells) synchronously initiate a phase of cell division to begin a cycle. The progeny cells then proliferate, migrate and differentiate, providing the substrate that drives physiological change over long time-spans (e.g. summer/winter); cell death may be required to trigger the next cycle. We have begun to characterise such a tissue-based timer in our Soay sheep model focusing on the pars tuberalis (PT) of the pituitary gland and the sub-ventricular zone of the mediobasal hypothalamus (MBH) as potential circannual pacemakers. The PT is of special interest because it is a melatonin-responsive tissue containing undifferentiated cells, strategically located at the gateway between the brain and pituitary gland. The PT also governs long-photoperiod activation of thyroid hormone dependant processes in the MBH required for neurogenesis. In sheep, exposure to long photoperiod markedly activates BrDU-labelled cell proliferation in the PT and MBH, and acts to entrain the circannual reproductive cycle. Variation in expression and co-ordination of multiple tissue timers may explain species differences in circannual rhythmicity. This paper is dedicated to the memory of Ebo Gwinner. PMID:21755671

Lincoln, G A; Hazlerigg, D G

2010-01-01

213

Haemodynamic advantage with single chamber rate responsive pacemakers over dual chamber pacemakers during exercise in chronotropic incompetence.  

PubMed

Sequential cardiac chamber activation and chronotropic response are amongst the important determinants of cardiac performance. This study compared VVIR mode with DDD and VVI mode to assess the contribution of these two factors in the determination of cardiac performance during exercise. Ten patients with a mean age of 68 +/- 5 years were studied during 1988-90, who had complete heart block and sinus node dysfunction with a mean LV ejection fraction of 51.5 +/- 6.25%. Five patients had DDD pacemakers and the rest had VVIR pacemakers. Patients were exercised first in VVI mode followed by either DDD or VVIR mode. Exercise duration, maximum rate pressure product, exercise capacity and cardiac output were measured with graded treadmill test in Bruce protocol. There was remarkable increase in the exercise duration (P < 0.001) and the maximum rate pressure product (P < 0.001) in patients with VVIR as compared to DDD and VVI mode. In DDD mode, as compared to VVI mode, this increase was less remarkable, though statistically significant (P < 0.005). Therefore, it is concluded that patients with chronotropic incompetence as well as complete heart block do better during dynamic exercise when they have VVIR mode compared to VVI or DDD mode. PMID:1289220

Maity, A K; Ghosh, S P; Dasbiswas, A; Chatterjee, S S; Chaudhury, D; Das, M K

214

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

215

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

216

Pacemaker Lead Endocarditis Due to Multidrug-Resistant Corynebacterium striatum Detected with Sonication of the Device ?  

PubMed Central

Corynebacterium striatum is a commensal of human skin and has been recently recognized as an emerging pathogen. A case of nosocomial pacemaker lead endocarditis due to a multidrug-resistant C. striatum strain is described, highlighting the role of sonication as a diagnostic tool in cardiac device infections.

Oliva, Alessandra; Belvisi, Valeria; Iannetta, Marco; Andreoni, Carolina; Mascellino, Maria T.; Lichtner, Miriam; Vullo, Vincenzo; Mastroianni, Claudio M.

2010-01-01

217

Effects of Cardiac Rehabilitation Program on Right Ventricular Function after Coronary Artery Bypass Graft Surgery  

PubMed Central

Background Cardiac rehabilitation has been recognized as one of the most effective strategies for managing cardiovascular indices as well as controlling the cardiovascular risk profile, in particular after coronary artery bypass graft surgery (CABG). However, the effect of this program on right ventricular function following CABG is unclear. The aim of this study was to evaluate the impact of cardiac rehabilitation on the right ventricular (RV) function in a cohort of patients who underwent CABG. Methods: A total of 28 patients who underwent CABG and participated consecutively in an 8-week cardiac rehabilitation program at Tehran Heart Center were studied. The control group consisted of 39 patients who refused to attend cardiac rehabilitation and only received postoperative medical treatment after registration in the Cardiac Rehabilitation Clinic. Two-dimensional and Doppler echocardiography was performed to assess the RV function in both groups at the three time points of before surgery, at the end of surgery, and at the end of the rehabilitation program. Results: Significant increase of RV function parameters were observed in both rehabilitation group (RG) and control group (CG) at the end of the rehabilitation program compared with post-CABG evaluation in terms of tricuspid annular plane systolic execution (RG: 12.50 mm to 14.18 mm; CG: 13.41 mm to 14.56 mm), tricuspid annular peak systolic velocity (RG: 8.55 cm/s to 9.14 cm/s; CG: 9.03 cm/s to 9.26 cm/s), and tricuspid annular late diastolic velocity (RG: 8.93 cm/s to 9.39 cm/s; CG: 9.26 cm/s to 9.60 cm/s).The parameters of the RV function did improve in both groups, but this improvement was not associated with participation in the complete cardiac rehabilitation program. Conclusion: The RV function parameters gradually improved after CABG; this progress, however, was independent of the exercise-based cardiac rehabilitation program.

Zoroufian, Arezoo; Taherian, Ali; Hosseini, Seyed Kianoosh; Sardari, Akram; Sheikhvatan, Mehrdad

2012-01-01

218

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

219

A Web of Circadian Pacemakers  

Microsoft Academic Search

The mammalian circadian timing system is composed of almost as many individual clocks as there are cells. These countless oscillators have to be synchronized by a central pacemaker to coordinate temporal physiology and behavior. Recently, there has been some progress in understanding the relationship and communication mechanisms between central and peripheral clocks.

Ueli Schibler; Paolo Sassone-Corsi

2002-01-01

220

Contemporary pacemakers: what the primary care physician needs to know.  

PubMed

Pacemaker therapy is most commonly initiated because of symptomatic bradycardia, usually resulting from sinus node disease. Randomized multicenter trials assessing the relative benefits of different pacing modes have made possible an evidence-based approach to the treatment of bradyarrhythmias. During the past several decades, major advances in technology and in our understanding of cardiac pathophysiology have led to the development of new pacing techniques for the treatment of heart failure in the absence of bradycardia. Left ventricular or biventricular pacing may improve symptoms of heart failure and objective measurements of left ventricular systolic dysfunction by resynchronizing cardiac contraction. However, emerging clinical data suggest that long-term right ventricular apical pacing may have harmful effects. As the complexity of cardiac pacing devices continues to grow, physicians need to have a basic understanding of device indications, device function, and common problems encountered by patients with devices in the medical and home environment. PMID:18828980

Kaszala, Karoly; Huizar, Jose F; Ellenbogen, Kenneth A

2008-10-01

221

Safety Of Mris In Patients With Pacemakers And Defibrillators  

PubMed Central

With a burgeoning population, increases in life expectancy, and expanding indications, the number of patients with cardiac devices such as pacemakers and implantable cardioverter defibrillators continues to increase each year. A majority of these patients will develop an indication for magnetic resonance imaging (MRI) in their lifetime. MRIs have established themselves as one of the most powerful imaging tools for a variety of conditions. However, given the historic safety concerns, many physicians are reluctant to use MRIs in this patient population. In this paper, we discuss the potential adverse effects of MRIs in patients with cardiac devices, review key studies that have addressed strategies to limit adverse effects, and provide our cardiovascular MRI laboratory’s protocol for imaging patients with implanted cardiac devices.

Baher, Alex; Shah, Dipan

2013-01-01

222

Safety of MRIs in patients with pacemakers and defibrillators.  

PubMed

With a burgeoning population, increases in life expectancy, and expanding indications, the number of patients with cardiac devices such as pacemakers and implantable cardioverter defibrillators continues to increase each year. A majority of these patients will develop an indication for magnetic resonance imaging (MRI) in their lifetime. MRIs have established themselves as one of the most powerful imaging tools for a variety of conditions. However, given the historic safety concerns, many physicians are reluctant to use MRIs in this patient population. In this paper, we discuss the potential adverse effects of MRIs in patients with cardiac devices, review key studies that have addressed strategies to limit adverse effects, and provide our cardiovascular MRI laboratory's protocol for imaging patients with implanted cardiac devices. PMID:24066196

Kodali, Santhisri; Baher, Alex; Shah, Dipan

2013-07-01

223

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

224

Symptomatic subclavian vein stenosis and occlusion in hemodialysis patients with transvenous pacemakers.  

PubMed

The objective of this study was to determine the incidence and timing of complications associated with ipsilateral transvenous pacemakers and hemodialysis access, including subclavian vein stenosis and occlusion, and assess their impact on dialysis access patency. All patients who had pacemakers placed at St. Francis Medical Center were reviewed during the 10-year period from 1988 to 1998. Patients requiring chronic hemodialysis were identified and their demographic data, the presence of arm swelling, and fistula patency were noted. Development of subclavian vein stenosis and occlusion was documented by venography in symptomatic patients. The ultimate outcome of dialysis access was recorded. During the 10-year period 495 patients had transvenous pacemakers placed. Twenty patients were identified with renal failure requiring hemodialysis and 14 had hemodialysis access in the extremity ipsilateral to the pacemaker. Ten (10/14, 71%) patients developed symptoms of subclavian stenosis, including venous hypertension, high recirculation rate, arm swelling, pain, and neurologic symptoms. Eighty percent (8/10) of symptomatic patients had subclavian vein occlusion. All 10 symptomatic patients required ligation of the hemodialysis access to control symptoms. The four asymptomatic patients expired within 6 months of placement of the pacemaker or hemodialysis access from unrelated causes. There is a high incidence of complications in patients who have ipsilateral pacemakers and hemodialysis access. The presence of pacemaker electrodes in the subclavian vein and the flow associated with hemodialysis may accelerate the occurrence of subclavian venous stenosis and occlusion. Patients who did not develop symptoms may have expired before venous outflow obstruction could develop. Vascular surgeons and cardiac surgeons/cardiologists need to coordinate their procedures to avoid ipsilateral transvenous pacemakers and hemodialysis access. PMID:12958674

Teruya, Theodore H; Abou-Zamzam, Ahmed M; Limm, Whitney; Wong, Linda; Wong, Livingston

2003-09-10

225

Programmable pacemakers: technical features and clinical applications.  

PubMed

With each new generation of pacing systems, there appears to be a renewed interest in providing the physician with something else to program. Many of the aforementioned parameters that have been programmable options in single-chamber devices are now selectively available in two-channel units. A growing interest in telemetry that offers the physician a means of electronic dialogue with the pulse generator to assess existing parameters, battery voltage, and hermeticity, and provides transmission of such data as an intracavitary ECG, arrhythmia monitoring, and historical data on the patient are variations of programmability soon to be increasingly available. A major responsibility is arising for the physician who reprograms an implanted pacemaker system to maintain accurate records and ensure that the patient and other physicians are aware of any new adjustments. Failure to do so risks needless removal of otherwise properly functioning devices by other physicians with whom the patient may interact. Thus, while programmability has widened the horizons for noninvasive adjustment of existing pacemaker performance, it has also markedly complicated the record-keeping responsibilities of the monitoring physician. PMID:6357441

Harthorne, J W

1983-01-01

226

High-intensity track and field training in a cardiac rehabilitation program  

PubMed Central

A 65-year-old male athlete with coronary artery disease enrolled in our cardiac rehabilitation (CR) program after successful coronary artery bypass graft surgery following an acute myocardial infarction. Unlike the typical sedentary cardiac patient in his age group, he loved to participate in hurdle events at masters division track meets (competitions for athletes aged 30 years and older). He expressed a strong desire to return to his sport, so we designed a sport-specific, symptom-limited exercise program that enabled him to train safely but at a higher intensity than is typically allowed in conventional CR programs. Although his measured peak heart rates during the sport-specific sessions were significantly higher than the calculated maximum heart rate limits usually imposed on patients during conventional CR exercise training, the patient had no adverse events and safely reached his fitness goal. When developing a CR plan, health care professionals should consider the patient's goals, not just his or her age.

Adams, Jenny; Cheng, Dunlei; Berbarie, Rafic F.

2012-01-01

227

Mathematical modeling of the entrainment of asymmetrical cardiac cell pairs  

Microsoft Academic Search

Complex multidimensional interactions between spatial distributions of Intrinsic cellular electrical properties and intercellular coupling resistances underlie the activation patterns related to sinus node function. In the present study we have used a model of two coupled cardiac cells, a pacemaker and a non pacemaker cell, to investigate the dependence of successful conduction on three components of the system: (1) the

Mayer Landau; Paco Lorente

1992-01-01

228

Pacemaker lead thrombo-endocarditis in an intravenous drug abuser  

Microsoft Academic Search

We report a 30-year-old male intravenous drug abuser presenting with persistent pacemaker lead thrombosis with superimposed pacemaker lead endocarditis. He underwent urgent surgery, but expired due to refractory sepsis. This case confirms that patients with pacemakers are at risk of developing pacemaker lead thrombosis. In addition, they are at high risk of developing pacemaker lead endocarditis if additional risk factors

Prashanth Panduranga; Mohammed Khamis Mukhaini

2011-01-01

229

Use of the fluid column in a cardiac catheter for emergency pacing.  

PubMed

Given the not infrequent need for intracardiac pacemaking during intensive cardiac care, a new type of cardiac pacemaker has been designed and tested [1]. With this pacemaker the heart can be stimulated through the fluid column of any conventional catheter, provided it is filled with a 0.9% NaCl solution. This fluid column pacemaker (FCP) is of the "constant current" type. The FCP was tested in 37 animals, in 30 patients in sinus rhythm, and also in two critical patients. In addition to the pacemaker circuit, a special connector was designed, enabling a fast, effective, and safe contact between patient and pacemaker. The FCP is considered to be ideally suited for use in emergency cardiac pacing in intensive care units and other areas where sudden bradycardias may occur and where intrathoracic catheters are inserted for a variety of reasons. PMID:6640667

Meester, G T; Simoons, M L; Slager, C J; Kint, P P; Spaa, W; Hugenholtz, P G

1983-01-01

230

Pacemaker channel dysfunction in a patient with sinus node disease  

PubMed Central

The cardiac pacemaker current If is a major determinant of diastolic depolarization in sinus nodal cells and has a key role in heartbeat generation. Therefore, we hypothesized that some forms of “idiopathic” sinus node dysfunction (SND) are related to inherited dysfunctions of cardiac pacemaker ion channels. In a candidate gene approach, a heterozygous 1-bp deletion (1631delC) in exon 5 of the human HCN4 gene was detected in a patient with idiopathic SND. The mutant HCN4 protein (HCN4-573X) had a truncated C-terminus and lacked the cyclic nucleotide–binding domain. COS-7 cells transiently transfected with HCN4-573X cDNA indicated normal intracellular trafficking and membrane integration of HCN4-573X subunits. Patch-clamp experiments showed that HCN4-573X channels mediated If-like currents that were insensitive to increased cellular cAMP levels. Coexpression experiments showed a dominant-negative effect of HCN4-573X subunits on wild-type subunits. These data indicate that the cardiac If channels are functionally expressed but with altered biophysical properties. Taken together, the clinical, genetic, and in vitro data provide a likely explanation for the patient’s sinus bradycardia and the chronotropic incompetence.

Schulze-Bahr, Eric; Neu, Axel; Friederich, Patrick; Kaupp, U. Benjamin; Breithardt, Gunter; Pongs, Olaf; Isbrandt, Dirk

2003-01-01

231

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

PubMed

Cardiovascular disease (CVD) is the leading cause of mortality in Australia, and places large burdens on the healthcare system. To assist patients with CVDs in recovering from cardiac events and mediating cardiac risk factors, a home based cardiac rehabilitation program, known as the Care Assessment Platform (CAP), was developed. In the CAP program, patients are required to manually enter health information into their mobile phones on a daily basis. The manual operation is often subject to human errors and is inconvenient for some elderly patients. To improve this, an automated wireless solution has been desired. The objectives of this paper are to investigate the feasibility of implementing the newly released Bluetooth 4.0 (BT4.0) for the CAP program, and practically evaluate BT4.0 communications between a developed mobile application and some emulated healthcare devices. The study demonstrated that BT4.0 addresses usability, interoperability and security for healthcare applications, reduces the power consumption in wireless communication, and improves the flexibility of interface for software development. This evaluation study provides an essential mobile BT4.0 framework to incorporate a large range of healthcare devices for clinical assessment and intervention in the CAP program, and hence it is useful for similar development and research work of other mobile healthcare solutions. PMID:22797030

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

2012-01-01

232

Pacemaker lead extraction with the laser sheath: results of the pacing lead extraction with the excimer sheath (PLEXES) trial 1 1 No financial support was received for performing the procedures or collecting the data, or for data analysis  

Microsoft Academic Search

OBJECTIVESThe purpose of this study was to evaluate the safety and effectiveness of pacemaker lead extraction with the excimer sheath in comparison to nonlaser lead extraction.BACKGROUNDFibrotic attachments that develop between chronically implanted pacemaker leads and to the venous, valvular and cardiac structures are the major obstacles to safe and consistent lead extraction. Locking stylets and telescoping sheaths produce a technically

Bruce L Wilkoff; Charles L Byrd; Charles J Love; David L Hayes; T. Duncan Sellers; Raymond Schaerf; Victor Parsonnet; Laurence M Epstein; Robert A Sorrentino; Christopher Reiser

1999-01-01

233

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

SciTech Connect

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

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

1987-10-01

234

The possible roles of hyperpolarization-activated cyclic nucleotide channels in regulating pacemaker activity in colonic interstitial cells of Cajal.  

PubMed

BACKGROUND: Hyperpolarization-activated cyclic nucleotide (HCN) channels are pacemaker channels that regulate heart rate and neuronal rhythm in spontaneously active cardiac and neuronal cells. Interstitial cells of Cajal (ICCs) are also spontaneously active pacemaker cells in the gastrointestinal tract. Here, we investigated the existence of HCN channel and its role on pacemaker activity in colonic ICCs. METHODS: We performed whole-cell patch clamp, RT-PCR, and Ca(2+)-imaging in cultured ICCs from mouse mid colon. RESULTS: SQ-22536 and dideoxyadenosine (adenylate cyclase inhibitors) decreased the frequency of pacemaker potentials, whereas both rolipram (cAMP-specific phosphodiesterase inhibitor) and cell-permeable 8-bromo-cAMP increased the frequency of pacemaker potentials. CsCl, ZD7288, zatebradine, clonidine (HCN channel blockers), and genistein (a tyrosine kinase inhibitor) suppressed the pacemaker activity. RT-PCR revealed expression of HCN1 and HCN3 channels in c-kit and Ano1 positive colonic ICCs. In recordings of spontaneous intracellular Ca(2+) [Ca(2+)]i oscillations, rolipram and 8-bromo-cAMP increased [Ca(2+)]i oscillations, whereas SQ-22536, CsCl, ZD7288, and genistein decreased [Ca(2+)]i oscillations. CONCLUSIONS: HCN channels in colonic ICCs are tonically activated by basal cAMP production and participate in regulation of pacemaking activity. PMID:23780559

Shahi, Pawan Kumar; Choi, Seok; Zuo, Dong Chuan; Kim, Man Yoo; Park, Chan Guk; Kim, Young Dae; Lee, Jun; Park, Kyu Joo; So, Insuk; Jun, Jae Yeoul

2013-06-19

235

21 CFR 870.3690 - Pacemaker test magnet.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

236

21 CFR 870.1750 - External programmable pacemaker pulse generator.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false External programmable pacemaker pulse generator. 870.1750 ...870.1750 External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker pulse generators is a device...

2013-04-01

237

21 CFR 870.3730 - Pacemaker service tools.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Pacemaker service tools. 870.3730 Section...Cardiovascular Prosthetic Devices § 870.3730 Pacemaker service tools. (a) Identification. Pacemaker service tools are devices such as...

2013-04-01

238

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

239

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

240

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

241

21 CFR 870.3720 - Pacemaker electrode function tester.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Pacemaker electrode function tester. 870...Prosthetic Devices § 870.3720 Pacemaker electrode function tester. (a) Identification. A pacemaker electrode function tester is a...

2013-04-01

242

21 CFR 870.3710 - Pacemaker repair or replacement material.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Pacemaker repair or replacement material. ...Prosthetic Devices § 870.3710 Pacemaker repair or replacement material. (a) Identification. A pacemaker repair or replacement material...

2013-04-01

243

21 CFR 870.3650 - Pacemaker polymeric mesh bag.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Pacemaker polymeric mesh bag. 870.3650 ...Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted...

2013-04-01

244

21 CFR 870.3640 - Indirect pacemaker generator function analyzer.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Indirect pacemaker generator function analyzer. 870...Devices § 870.3640 Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker generator function analyzer is...

2010-04-01

245

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

246

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

247

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

248

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

249

21 CFR 870.3610 - Implantable pacemaker pulse generator.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Implantable pacemaker pulse generator. 870.3610 Section 870... § 870.3610 Implantable pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a...

2009-04-01

250

21 CFR 870.1750 - External programmable pacemaker pulse generator.  

Code of Federal Regulations, 2010 CFR

...false External programmable pacemaker pulse generator. 870.1750 Section 870...1750 External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker pulse generators is a device that can...

2010-04-01

251

21 CFR 870.3610 - Implantable pacemaker pulse generator.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Implantable pacemaker pulse generator. 870.3610 Section 870... § 870.3610 Implantable pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a...

2010-04-01

252

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

253

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

254

Type and timing of permanent pacemaker failure.  

PubMed

Availability of lithium batteries will decrease the incidence of early pacemaker failure. Pacemaker malfunction, exclusive of that due to battery exhaustion, can still occur. Defined as any repeat surgical procedure required after initial implantation, pacemaker system failure occurred in 22 of 115 (19 percent) pacemaker patients. Failure occurred within the first month in 12 with ten being lead-related. Insertion site problems occurred in nine patients. Though most endocardial pacemaker complications occur early, patients continue to be at risk for as long as the units are in place. Despite improvements in the batteries, there continue to be sufficient problems with pacemakers to emphasize the need for selectivity in determining which patients receive permanent units. PMID:7067508

Reinhart, S; McAnulty, J H; Dobbs, J

1982-04-01

255

Study of interactions between permanent pacemakers and electronic antitheft surveillance systems.  

PubMed

Interference of electronic antitheft systems (EASs) with pacemakers has been an object of controversy. This study was performed in 204 patients followed by our pacemaker surveillance center. The data from a total of 408-patient exposures to the EAS were analyzed. The device tested consisted of 129 DDD, 71 VVI, and 4 VDD pacemakers from seven manufacturers. The EAS studied consisted of an "acoustomagnetic" system that emits an intermittent 58-kHz signal, and a magnetic audio frequency system that emits a continuous 73-Hz signal. Complete interrogation of the pacemakers was performed before and after the consecutive exposure of the patients to both EASs. Electrocardiograms were recorded while the patients were exposed to the magnetic fields of each EAS for up to 30 seconds. One or more EAS interferences occurred in 17% of patients. EAS was observed in 26 (20%) of 129 patients with DDD, 7 (10%) of 71 patients with VVI, and 2 (50%) of 4 patients with VDD pacemakers. Over twice as many instances of EAS interference were observed with the "acoustomagnetic" system as were with the magnetic audio frequency system. Among pacemakers programmed in the DDD mode, a considerably greater prevalence of interference was observed at the atrial versus ventricular level, despite the same programmed sensing polarity in both chambers in all but one case. Sensing anomalies were the most common EAS induced disturbance, and typically lasted for the duration of exposure. In a few instances of pacing inhibition, the phenomenon was limited to 1 cycle at the onset of EAS exposure. No changes occurred in the programming of the pacemakers, and a single patient experienced palpitation during EAS induced rapid pacing. During exposure to EAS mimicking the normal use of the systems, interference with a variety of pacemakers was relatively common. However, the anomalies observed were transient and the cause of no symptom or device reprogramming. Patients should be advised to not stand unnecessarily in the close proximity of EASs. PMID:10750133

Mugica, J; Henry, L; Podeur, H

2000-03-01

256

Improved treatment of coronary heart disease by implementation of a Cardiac Hospitalization Atherosclerosis Management Program (CHAMP)  

Microsoft Academic Search

Despite scientific evidence that secondary prevention medical therapies reduce mortality in patients with established coronary artery disease, these therapies continue to be underutilized in patients receiving conventional care. To address this issue, a Cardiac Hospital Atherosclerosis Management Program (CHAMP) focused on initiation of aspirin, cholesterol-lowering medication (hydroxymethylglutaryl coenzyme A [HMG CoA] reductase inhibitor titrated to achieve low-density lipoprotein [LDL] cholesterol

Gregg C Fonarow; Anna Gawlinski; Samira Moughrabi; Jan H Tillisch

2001-01-01

257

Reconstruction of Hyman's second pacemaker.  

PubMed

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

Furman, Seymour; Szarka, George; Layvand, Dmitriy

2005-05-01

258

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

SciTech Connect

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

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

2003-06-01

259

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

260

Presynaptic irregularity and pacemaker inhibition  

Microsoft Academic Search

It is known (e.g., Perkel et al., 1964) that when a pacemaker neuron elicits IPSP's in another, there are domains called “paradoxical segments” where in the steady-state i) faster inhibitory discharges determine faster inhibited ones, and ii) pre- and postsynaptic spikes are “locked” in an invariant forward-and-backward positioning in time, spikes alternating in the ratios 1:1 (1 pere for 1

A. F. Kohn; A. Freitas da Rocha; J. P. Segundo

1981-01-01

261

[Exercise test in patients with permanent pacemakers].  

PubMed

From June 1988 to June 1990 we studied fifty patients who had implantation of a pacemaker. (31 females and 19 males). All of them underwent stress test with Bruce's protocol. Patients were divided in two groups; pacemaker-independent (PI) and pacemaker-dependent (PD). Over 50% of the patients inhibited the pacemaker with their own rhythm, most of them had sinus dysfunction. Complete A-V block was predominant in PD. The group of PI achieved more mets and had more oxygen consumption. Blood pressure response was similar in both groups. PMID:1929668

Esturau, R; Iturralde, P; Férez, S; Galván, O; Rosado, J; Pérez, G; González Hermosillo, J A

262

21 CFR 870.3630 - Pacemaker generator function analyzer.  

Code of Federal Regulations, 2013 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3630 Pacemaker generator function analyzer. (a) Identification. A pacemaker generator...

2013-04-01

263

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

Microsoft Academic Search

Background  People with cardiac disease and type 2 diabetes have higher hospital readmission rates (22%) compared to those without diabetes\\u000a (6%). Self-management is an effective approach to achieve better health outcomes; however there is a lack of specifically\\u000a designed programs for patients with these dual conditions. This project aims to extend the development and pilot test of a\\u000a Cardiac-Diabetes Self-Management Program

Chiung-Jung Jo Wu; Anne M Chang; Mary Courtney; Lillie M Shortridge-Baggett; Karam Kostner

2011-01-01

264

Environmental Effects on Cardiac Pacing Systems  

Microsoft Academic Search

Early artificial pacemakers delivered asynchronous pulses at a fixed rate regardless of the intrinsic activity of the heart.\\u000a As pacemaker technology improved, devices were developed that not only delivered pacing stimuli but also sensed intrinsic\\u000a cardiac electrical activity. However, the circuitry used to detect small amplitude (1–20 mV) intracardiac electrical signals\\u000a generated by the atrium and ventricle can also detect

Louise Cohan; Fred M. Kusumoto; Nora F. Goldschlager

265

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

PubMed

The curricula "Practice of Pacemaker Therapy" and "Practice of ICD Therapy" have been developed from practical experience with the first educational courses which are necessary to fulfill the German requirements of the medical products law which restricts the application of medical products to persons with the necessary education, knowledge and experience. The corresponding courses of competence under the auspices of the German Cardiac Society derive from this legal prerequisite. Competence refers to technical knowledge in cardiac implantable electrical devices (CIEDs) and understanding of possible dysfunctions as well as substantial knowledge on arrhythmia. The two curricula form the theoretical basis for the application of CIEDs. These courses represent an offer to cardiologists and all other physicians who wish to acquire and document competency in this field. A legal obligation to participate in these competency courses does not currently exist in Germany as long as evidence can be provided that this competency has been achieved by other means. Both curricula have proven to be comprehensive and practically highly useful and have been presented by highly committed specialists with expertise in this topic at a high level. Since 2005 some 2,000 physicians have been trained in courses on pacemaker therapy and more than 1,000 physicians in courses on ICD therapy with an ongoing high level demand to be expected in the future. PMID:20835712

Krämer, L-I; Griebenow, R

2010-09-01

266

Cardiac Arrhythmias in the Elderly  

Microsoft Academic Search

Cardiac arrhythmias are more frequent in the elderly population due to an increased prevalence of hyperten- sion and coronary disease as well as from the gradual and natural loss of pacemaker and conducting cells. Although often asymptomatic, arrhythmias in the eld- erly may be a poor prognostic sign in the presence of heart disease and are more often associated with

Andrew Prieto; Ranjan K. Thakur

1999-01-01

267

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

268

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

269

Self-organized pacemakers in birhythmic media  

NASA Astrophysics Data System (ADS)

A birhythmic dynamical system is characterized by two coexisting stable limit cycles. In this article, a general reaction-diffusion system close to a supercritical pitchfork-Hopf bifurcation is investigated, where a soft onset of birhythmicity is possible. We show that stable self-organized pacemakers, which give rise to target patterns, exist and represent a generic type of spatio-temporal patterns in such a system. This is verified by numerical simulations which also show the existence of breathing and swinging pacemaker solutions. Stable pacemakers inhibit the formation of other pacemakers in the system. The drift of self-organized pacemakers in media with spatial parameter gradients is analytically and numerically investigated. Furthermore, instabilities induced by phase slips are also considered.

Stich, Michael; Ipsen, Mads; Mikhailov, Alexander S.

2002-10-01

270

[Pacemaker syndrome with AV-synchronized stimulation of the heart].  

PubMed

Characteristic signs of the pacemaker syndrome occurred in a 69-year-old woman with intermittent 3 degrees atrioventricular (AV) block after implantation of a dual-chamber AV-synchronized pacemaker. Cannon beats due to inappropriate atrial timing were the main haemodynamic finding. Their development and size depended on the programmed AV interval and AV-synchronized mode of stimulation. Very long AV intervals in the DDD mode at a heart rate of 100/min caused very unpleasant palpitations and pulsations in the upper thorax. The symptoms due to the cannon beats were avoided by changing to a short AV interval. The clinical and haemodynamic events were thus the consequence of preserved sinus node function with subsequent atrial triggering. PMID:1748068

Stierle, U; Potratz, J; Taubert, G; Mitusch, R; Sheikhzadeh, A; Diederich, K W

1991-12-13

271

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

272

Characterizing a mammalian circannual pacemaker.  

PubMed

Many species express endogenous cycles in physiology and behavior that allow anticipation of the seasons. The anatomical and cellular bases of these circannual rhythms have not been defined. Here, we provide strong evidence using an in vivo Soay sheep model that the circannual regulation of prolactin secretion, and its associated biology, derive from a pituitary-based timing mechanism. Circannual rhythm generation is seen as the product of the interaction between melatonin-regulated timer cells and adjacent prolactin-secreting cells, which together function as an intrapituitary "pacemaker-slave" timer system. These new insights open the way for a molecular analysis of long-term timing mechanisms. PMID:17185605

Lincoln, Gerald A; Clarke, Iain J; Hut, Roelof A; Hazlerigg, David G

2006-12-22

273

High-intensity track and field training in a cardiac rehabilitation program.  

PubMed

A 65-year-old male athlete with coronary artery disease enrolled in our cardiac rehabilitation (CR) program after successful coronary artery bypass graft surgery following an acute myocardial infarction. Unlike the typical sedentary cardiac patient in his age group, he loved to participate in hurdle events at masters division track meets (competitions for athletes aged 30 years and older). He expressed a strong desire to return to his sport, so we designed a sport-specific, symptom-limited exercise program that enabled him to train safely but at a higher intensity than is typically allowed in conventional CR programs. Although his measured peak heart rates during the sport-specific sessions were significantly higher than the calculated maximum heart rate limits usually imposed on patients during conventional CR exercise training, the patient had no adverse events and safely reached his fitness goal. When developing a CR plan, health care professionals should consider the patient's goals, not just his or her age. PMID:22275782

Kennedy, Kathleen; Adams, Jenny; Cheng, Dunlei; Berbarie, Rafic F

2012-01-01

274

Analysis of 3D motion of in-vivo pacemaker leads  

NASA Astrophysics Data System (ADS)

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

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

1997-04-01

275

Feasibility of the automatic generating system (AGS) for quartz watches as a leadless pacemaker power source: a preliminary report  

Microsoft Academic Search

An automatic power generating system developed for quartz watches was tested as a power source for implantable cardiac pacemakers. An automatic power generating mechanism and a capacitor (0.33 F) were taken out of a quartz watch and encapsulated in a polyvinyl case (AGS). Characteristics of the AGS were investigated by reciprocating equipment (2 Hz). The capacitor in the AGS was

H. Goto; T. Sugiura; T. Kazui

1998-01-01

276

Damaging effect of therapeutic radiation on programmable pacemakers  

SciTech Connect

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

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

1982-03-01

277

A role for Sp and nuclear receptor transcription factors in a cardiac hypertrophic growth program  

PubMed Central

During cardiac hypertrophy, the chief myocardial energy source switches from fatty acid ?-oxidation (FAO) to glycolysis—a reversion to fetal metabolism. The expression of genes encoding myocardial FAO enzymes was delineated in a murine ventricular pressure overload preparation to characterize the molecular regulatory events involved in the alteration of energy substrate utilization during cardiac hypertrophy. Expression of genes involved in the thioesterification, mitochondrial import, and ?-oxidation of fatty acids was coordinately down-regulated after 7 days of right ventricular (RV) pressure overload. Results of RV pressure overload studies in mice transgenic for the promoter region of the gene encoding human medium-chain acyl-CoA dehydrogenase (MCAD, which catalyzes a rate-limiting step in the FAO cycle) fused to a chloramphenicol acetyltransferase reporter confirmed that repression of MCAD gene expression in the hypertrophied ventricle occurred at the transcriptional level. Electrophoretic mobility-shift assays performed with MCAD promoter fragments and nuclear protein extracts prepared from hypertrophied and control RV identified pressure overload-induced protein/DNA interactions at a regulatory unit shown previously to confer control of MCAD gene transcription during cardiac development. Antibody “supershift” studies demonstrated that members of the Sp (Sp1, Sp3) and nuclear hormone receptor [chicken ovalbumin upstream promoter transcription factor (COUP-TF)/erbA-related protein 3] families interact with the pressure overload-responsive unit. Cardiomyocyte transfection studies confirmed that COUP-TF repressed the transcriptional activity of the MCAD promoter. The DNA binding activities and nuclear expression of Sp1/3 and COUP-TF in normal fetal mouse heart were similar to those in the hypertrophied adult heart. These results identify a transcriptional regulatory mechanism involved in the reinduction of a fetal metabolic program during pressure overload-induced cardiac hypertrophy.

Sack, Michael N.; Disch, Dennis L.; Rockman, Howard A.; Kelly, Daniel P.

1997-01-01

278

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

279

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

Microsoft Academic Search

An automatic power-generating system (AGS) which converts kinetic energy into electric energy for quartz watches was tested\\u000a as a power source for implantable cardiac pacemakers. An automatic power-generating mechanism and a capacitor (0.33 F) were\\u000a removed from a quartz watch (SEIKO) and encapsulated in a polyvinyl case. Characteristics of the AGS were investigated by\\u000a acceleration equipment. The capacitor in the

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

1999-01-01

280

Pacemaker failure associated with therapeutic radiation  

SciTech Connect

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

Brooks, C.; Mutter, M.

1988-11-01

281

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

282

Adoption of community-based cardiac rehabilitation programs and physical activity following phase III cardiac rehabilitation in Scotland: A prospective and predictive study  

Microsoft Academic Search

Little is known about levels of physical activity and attendance at phase IV community-based Cardiac Rehabilitation (CR) programs following completion of exercise-focussed, hospital-based phase III CR. This study aims to test, compare and combine the predictive utility of the Common-Sense Self-Regulation Model (CS-SRM) and the extended Theory of Planned Behaviour (TPB) with action planning for two rehabilitation behaviours: physical activity

Falko F. Sniehotta; Charlotta Gorski; Vera Araújo-Soares

2010-01-01

283

The Impact of Early Regular Cardiac Rehabilitation Program on Myocardial Function after Acute Myocardial Infarction  

PubMed Central

Objective To determine if an early regular cardiac rehabilitation program would have an adverse effect on myocardial function after acute myocardial infarction (AMI). Method Patients who received percutaneous coronary intervention (PCI) after AMI were divided into the exercise group and control group in accordance with their willingness to participate. Patients in the exercise group (n=18) received ECG monitored exercise for six weeks and were instructed to maintain self exercise in their communities for four months. The control group (n=16) patients were just instructed of risk factor control. All the subjects underwent echocardiography at the time of the AMI as well as six months later. The echocardiography parameters, including the left ventricular ejection fraction (LVEF), stroke volume (SV), left ventricular end-diastolic diameter (LVEDD) and end-systolic diameter (LVESD), were measured. Results In the exercise group, the LVEF increased to 59.58±9.24% and 61.58±9.63% after six weeks and six months, respectively (p<0.05), but SV, LVEDD and LVESD did not change (p>0.05). Conclusion Active participation in the cardiac rehabilitation program approximately two weeks after AMI did not have an adverse effect on the size of the left ventricle and myocardial function.

Kim, Chul; Kim, Duk You

2011-01-01

284

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

PubMed

A school nurse has many obstacles to overcome when providing emergency care for an age group ranging from four to adulthood. The 21st century school nurse faces the challenges of providing care to medically fragile children at multiple sites, with high student-nurse ratios. The implementation of an Automated External Defibrillation (AED) program can assist the school nurse and staff in providing necessary life-saving services for Sudden Cardiac Arrest (SCA) victims of all ages. The purpose of this article is to describe AED program implementation in a school setting, including the need, essential elements, benefits, and potential concerns related to this vital component of the American Heart Association five-link chain of survival. PMID:23140410

Boudreaux, Sharon; Broussard, Lisa

2012-01-01

285

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

286

Wavelet Based Event Detection in Pacemakers.  

National Technical Information Service (NTIS)

This paper presents a detection algorithm for pacemakers which is based on a signal model including a linear combination of descriptive functions. The functions are defined as different time scales of the two fundamental waveforms in the electrogram. An e...

M. Astrom S. Olmos L. Sornmo

2001-01-01

287

Adverse pacemaker hemodynamics evaluated by pulmonary venous flow monitoring.  

PubMed

The pacemaker syndrome refers to symptoms and signs in the pacemaker patient caused by an inadequate timing of atrial and ventricular contractions. The lack of normal atrioventricular synchrony may result in a decreased cardiac output and venous cannon A waves. The objective of this study was to define the left atrial and pulmonary venous flow response to ventricular pacing in a group of 14 unselected consecutive patients with total heart block and sinus rhythm. Pulmonary venous flow was assessed by transesophageal pulsed Doppler echocardiography in the VVI and DDD pacing modes. An inappropriate atrial timing caused a marked augmentation of the normally small pulmonary venous z wave in all patients ("negative atrial kick," peak z wave in DDD pacing 14.5 +/- 4.6 cm/s, VVI pacing 51.8 +/- 15.0 cm/s). Restoration of AV synchrony (DDD pacing, AV interval 100 ms) abolished these "cannon z waves" in all patients, and a normal pattern of pulmonary venous flow was achieved. Abnormal pulmonary venous flow characteristics were observed in 2 of 14 patients during DDD pacing with short AV intervals (100 ms). The Doppler pattern was similar to the findings seen in VVI pacing. Assessment of pulmonary venous flow by transesophageal pulsed Doppler echocardiography may provide a simple, sensitive, and relatively noninvasive technique to evaluate patients with suspected pacing induced adverse hemodynamics. PMID:8552517

Stierle, U; Krüger, D; Mitusch, R; Potratz, J; Taubert, G; Sheikhzadeh, A

1995-11-01

288

Chronotropic response of an activity detecting pacemaker compared with the normal sinus node.  

PubMed

We compared the rate responsiveness of an activity-detecting multiprogrammable, single chamber pacemaker (Medtronic Activitrax) to rate responsiveness of the normal sinus node. This pacemaker changes its basic pacing rate in response to physical activity. The rate responsiveness is programmable by selecting one of three activity thresholds, and one of 10 rate response settings. The study included a group of six normal volunteers and 12 patients implanted with Activitrax to examine the similarity of the pacemaker rate to normal sinus rhythm during acceleration and deceleration. The pacemaker was set to Activity mode, at a basic rate of 60 bpm. In volunteers, the device was externally secured on the chest wall and tested at two programmed settings. When programmed at a high threshold of activity and high rate response in volunteers, there was no significant difference in maximum normal sinus rates and pacemaker rates during arm waving, jumping in place, and walking during stress testing. At a medium activity threshold, the only significant difference occurred during submaximal stress testing, when the maximum sinus rate achieved was 141 +/- 19 bpm and the maximum pacing rate was 105 +/- 8 bpm (p less than .02). The pacemaker behaved in a similar manner in patients, successfully simulating the typical fast acceleration and slow deceleration of a normal sinus node in exercise testing. There was no difference in pacer response when implanted in abdominal or infraclavicular locations. The implanted units have functioned normally over a follow-up period of nine to 22 months. Activitrax can be programmed to achieve physiologic pacing rates in response to normal daily activities with appropriate programming. PMID:2436172

Moura, P J; Gessman, L J; Lai, T; Gallagher, J D; White, M; Morse, D P

1987-01-01

289

Mangalith: a new lithium pacemaker battery  

SciTech Connect

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

Gerbier, G.; Lehmann, G.

1980-01-01

290

Pacemaker and Defibrillator Lead Extraction  

MedlinePLUS

... some heart failure patients. 1 Implantable cardioverter defibrillators stop dangerous rapid heart rhythms by delivering an electric shock. 2 As the range of applications widens, the number of patients with cardiac devices continues to increase. Approximately 400 000 devices are ...

291

Left ventricular malposition of pacemaker lead in Chagas' disease.  

PubMed

A 52-year-old Argentinian woman presented with third-degree AV block due to seropositive chronic stage of Chagas' disease. Subsequently, a DDD pacemaker was implanted. Interestingly, a postoperative chest X ray suggested left ventricular lead misplacement, an ECG showed a paced RBBB. Echocardiography confirmed suspected lead malposition in the left ventricle with perforation of a large aneurysm of the interatrial septum that might be related to Chagas' disease. The ventricular lead was successfully repositioned in the right ventricle. Therefore, to avoid lead malposition in Chagas' disease structural cardiac defects should always be ruled out before operation. If a paced RBBB indicates malposition, different fluoroscopic projections should be used to verify lead position. PMID:15613133

Chun, Julian K R; Bode, Frank; Wiegand, Uwe K H

2004-12-01

292

Hemodynamic advantages of temperature sensing rate adaptive pacemaker.  

PubMed

During activity, the increase in body temperature triggers the pacemaker to adjust by increasing the rate. To assess the hemodynamic advantages twelve patients were studied. Heart function was measured by a noninvasive bioimpedance method. Heart functions were measured first at rest and then at the end of the exercise. Exercise was done in temperature mode and then later at a fixed heart rate. Cardiac output increased by 64% in temp mode compared to the fixed heart rate during the exercise. Stroke Volume increased by 38%. The Thoracic Fluid Index, Ventricular Ejection Time, Ejection Velocity Index and Ejection Fraction were unchanged. Hemodynamics are better in temp sensing rate responsive pacing during activity compared to fixed rate pacing. Clinically, the patients are doing well. PMID:8276555

Rao, G

293

Prediction of drug-related cardiac adverse effects in humans--B: use of QSAR programs for early detection of drug-induced cardiac toxicities.  

PubMed

This report describes the use of three quantitative structure-activity relationship (QSAR) programs to predict drug-related cardiac adverse effects (AEs), BioEpisteme, MC4PC, and Leadscope Predictive Data Miner. QSAR models were constructed for 9 cardiac AE clusters affecting Purkinje nerve fibers (arrhythmia, bradycardia, conduction disorder, electrocardiogram, palpitations, QT prolongation, rate rhythm composite, tachycardia, and Torsades de pointes) and 5 clusters affecting the heart muscle (coronary artery disorders, heart failure, myocardial disorders, myocardial infarction, and valve disorders). The models were based on a database of post-marketing AEs linked to 1632 chemical structures, and identical training data sets were configured for three QSAR programs. Model performance was optimized and shown to be affected by the ratio of the number of active to inactive drugs. Results revealed that the three programs were complementary and predictive performances using any single positive, consensus two positives, or consensus three positives were as follows, respectively: 70.7%, 91.7%, and 98.0% specificity; 74.7%, 47.2%, and 21.0% sensitivity; and 138.2, 206.3, and 144.2 chi(2). In addition, a prospective study using AE data from the U.S. Food and Drug Administration's (FDA's) MedWatch Program showed 82.4% specificity and 94.3% sensitivity. Furthermore, an external validation study of 18 drugs with serious cardiotoxicity not considered in the models had 88.9% sensitivity. PMID:19941924

Frid, Anna A; Matthews, Edwin J

2009-11-24

294

Inhibition of ventricular stimulation in patients with dual chamber pacemakers and prolonged AV conduction.  

PubMed

Episodes of repetitive P wave undersensing have been described in dual chamber pacemakers due to automatic extension of the postventricular atrial refractory period (PVARP). Pacemaker stimulation was completely inhibited despite the presence of adequate P waves. This study sought to determine whether cycles of repetitive P wave undersensing occur even in the absence of PVARP extension. Two-hundred fifty-five patients were investigated after DDD or VDD pacemaker implantation for intermittent atrioventricular (AV) block. Forty-six episodes of repetitive atrial undersensing were found during 24-hour Holter ECG in nine patients. Pacemaker syndrome-like symptoms occurred. Episodes were elicited by atrial or ventricular premature contractions when (1) native AV conduction was present but considerably prolonged, (2) intrinsic sinus rate exceeded pacemaker intervention rate, and (3) native AV interval plus PVARP exceeded sinus cycle length. Programming of a particularly short AV interval and PVARP helped to reduce the incidence of repetitive P wave undersensing. Patients with dual chamber devices and prolonged native AV conduction are prone to develop episodes of output inhibition. Standard timing cycles may be inappropriate in these patients. PMID:10588143

Bode, F; Wiegand, U; Katus, H A; Potratz, J

1999-10-01

295

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

296

Effectiveness of a simulation-based educational program in a pediatric cardiac intensive care unit.  

PubMed

Optimal staff performance of resuscitation skills is best achieved through regular effective training. However, providing this teaching in a busy high-acuity pediatric cardiac intensive care unit (ICU) had become a challenge due to time and logistical constraints. A program to effectively and efficiently teach ICU nurses the skills necessary in patient resuscitation was developed using simulation training to better meet staff learning needs. Training via simulation provides an ideal learning environment with hands-on experience with the roles required in patient resuscitation. A simulation training program incorporating simulation training was developed for ICU nursing staff. All staff nurses in the ICU were required to attend over a year's time. The program involved mock resuscitation scenarios in which participants performed various resuscitation roles, followed by video review and group debriefing. All participants completed a survey prior to and immediately following participation in the training and again at 1 year. Data collected included self-report of knowledge, skill, and comfort related to patient resuscitation. Data revealed statistically significant improvement in scores pre and post training and at 1 year for self-reported knowledge, skills, and comfort related to resuscitation. Nursing staff reported that simulation training in resuscitation skills was helpful and positively impacted their knowledge, comfort, and skills. Feedback from nursing staff continues to be very positive, and performance of actual resuscitations on the unit has improved anecdotally. PMID:21726778

Kane, Janie; Pye, Sherry; Jones, Amber

2010-07-27

297

Immediate Effects of Intravenous Verapamil in Cardiac Arrhythmias  

Microsoft Academic Search

Verapamil was administered by intravenous injection to 181 patients with various cardiac arrhythmias. The automaticity of the cardiac pacemaker was slowed in sinus, idionodal, and idioventricular tachycardia. In atrial fibrillation the drug usually slowed the ventricular response and often made it regular. In some cases atrial flutter was converted to sinus rhythm, the ventricular response being reduced in the remainder.

L. Schamroth; D. M. Krikler; C. Garrett

1972-01-01

298

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

299

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

PubMed

Modern pacemakers, and particularly dual chamber models, include a broad array of therapeutic and diagnostic features. Some are designed to increase safety, whereas others are either designed to avoid unnecessary pacing, reduce the current drain and increase the pacemaker longevity, or to improve the hemodynamics. Diagnostic features are more elaborate, more or less automatic, and easier to extract from the pacemaker memory. Some of these new algorithms represent a real advantage, while others appear to be more like gadgets than real advances. Several new algorithms should be improved in order to avoid possibly dangerous side effects. Most of these new features are of little value in the absence of postoperative programming by a well trained physician. PMID:12555487

Dodinot, B

2000-07-01

300

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

Microsoft Academic Search

“Funny” (f) channels underlie the cardiacpacemaker”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

301

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

PubMed Central

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

Jalife, J

1984-01-01

302

21 CFR 870.3620 - Pacemaker lead adaptor.  

Code of Federal Regulations, 2013 CFR

...Classification. Class II (special controls). The special control for this device is the...the Submission of Research and Marketing Applications for Permanent Pacemaker...for Pacemaker Lead Adaptor 510(k) Submissions.â [45 FR...

2013-04-01

303

Treatment of superior vena caval obstruction following permanent pacemaker extraction.  

PubMed

Superior vena caval (SVC) obstruction following permanent pacemaker lead extraction is a serious but uncommon complication. This report describes the case of an 83-year-old man treated by balloon angioplasty and femoral pacemaker implantation. PMID:12520683

Newall, Nick; Stables, Rod; Palmer, Nick; Ramsdale, David

2002-12-01

304

Diagnosis of atrial undersensing in dual chamber pacemakers: impact of autodiagnostic features.  

PubMed

Atrial undersensing occurs in a considerable number of patients, both with single lead VDD pacemakers and with DDD devices. The aim of this study was to investigate the diagnostic efficacy of electrocardiographic methods and autodiagnostic pacemaker features to detect atrial sensing dysfunction. Two hundred and thirty-one patients with AV block received single lead VDD pacemakers or DDD devices. Atrial sensitivity was programmed to 0.1 or 0.18 in VDD devices and to 0.5 mV in DDD devices; the rate limits were set to 40 and 160 beats/min. Twelve-lead ECG recording for 1 minute during deep respiration and change of body position, 24-hour Holter ECG recording, and treadmill exercise were performed 2 weeks and 15 months after pacemaker implantation. AV synchrony and, if available, P wave amplitude histogram were sampled by autodiagnostic pacemaker features and compared to electrocardiographic findings. Atrial undersensing was assumed, if AV synchrony was below 100% or if minimal P wave amplitude (PWA) was equal to the programmed atrial sensitivity. Intermittent atrial undersensing occurred in 20.7% of patients. The diagnostic sensitivities of the various methods used to detect atrial sensing failures were: 24-hour Holter monitoring 97.5%, P wave amplitude histogram 90.0%, stored AV synchrony 68.0% without significant difference between the various devices, treadmill exercise testing 58.8%, and 12-lead ECG recording 21.3%. In one patient, atrial undersensing was exclusively detected by exercise testing. In conclusion, autodiagnostic pacemaker features facilitate the evaluation of atrial sensing performance. However, to exclude intermittent atrial malesensing, routine Holter monitoring and treadmill exercise are still needed. PMID:10392387

Wiegand, U K; Bode, F; Schneider, R; Brandes, A; Haase, H; Katus, H A; Potratz, J

1999-06-01

305

[Double-chamber pacemakers. Implantation in a schoolboy for a traumatic lesion of the conduction tissue].  

PubMed

The technological advance of artificial cardiac stimulation in the last fifteen years has been spectacular. The increased life span of generators brought on by the use of lithium batteries, as well as the new platinum anodized leads which reduce their polarization tension, increasing current density to a maximum and thereby lowering chronic stimulation thresholds, mark a new stage in artificial cardiac stimulation. During the current decade there have been three major advances: stimulation by means of DDD-type dual chamber pacemakers; generators activated by muscle movement; and the prototypes of cardioverter-defibrillator automatic pacemakers in the experimental phase. This is the case of an eleven-year-old schoolboy who suffered a traumatic lesion of conductive tissue by an accidental gunshot wound, lead shot being lodged in the proximities of the atrial-ventricular junction, resulting in stokes-Adams due to the presence of complete AV blockage, in whom a dual chamber symbios pacemaker was implanted by endocardial way, by which means he returned to a normal life even insofar as athletic activity is concerned. PMID:3214221

Patrón Amador, E; Quintal Flores, A; Vázquez Flores, M; Durán Cárdenas, M; Farjat Ruiz, J; Rosado López, L; Calpe Horta, J

306

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

PubMed Central

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

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

2010-01-01

307

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

308

Uniform pacemaker and ICD information system in the Netherlands  

Microsoft Academic Search

In the Netherlands the Central Pacemaker Patient Registry (CPPR) collects information of pacemaker and ICD (implantable cardio defibrillator) patients from all 109 Dutch hospitals. Many pacemaker clinics use a computer to store their implant and follow-up data in a database. Because the devices are getting more and more complex more clinical data is needed for optimal use of the device.

C. A. M. Hooijschuur; W. A. Dijk; W. van der Velde; B. Sanon; C. Ammeraal; W. R. M. Dassen; H. J. Spruijt

2002-01-01

309

[Activation of latent pacemakers in the guinea pig ureter].  

PubMed

Guinea pig's ureter rhythmogenic autonomous latent pacemaker was shown to generate a significantly higher-frequency rhythm than the pericystic pacemaker. The latent pacemakers of the ureter middle portion can be activated with a breach of electrical conductivity across the organ or with chemical agents (noradrenaline, histamine). PMID:11575129

Kazarian, K V; Vantsian, V Ts; Tiraian, A S; Akopian, R R

2001-07-01

310

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

PubMed

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

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

2013-10-18

311

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

312

Cardiac Pacing in the Critical Care Setting  

Microsoft Academic Search

Cardiac pacing can play an integral role in the management of critically ill patients. This role is not limited to the appropriate\\u000a implementation of temporary cardiac pacing, but also includes maximizing therapies already available through a patient’s previously\\u000a implanted permanent pacemaker or implantable cardioverter-defibrillator (ICD). Complications related to the implanted device\\u000a can also lead to a need for management within

Richard H. Hongo; Nora F. Goldschlager

313

[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

314

Sleep Syncope: Treatment with a Permanent Pacemaker  

PubMed Central

Vasovagal syncope usually occurs during upright posture, but Jardine et al. have described a variant that occurs at night. During “sleep syncope”, patients are awakened from sleep with nausea, abdominal cramping or a sense of impending diarrhea, get up, and faint in the bathroom. We report on a patient with recurrent sleep syncope (with physical injury) in whom an asystolic pause was documented during one of her “sleep syncope” spells. Implantation of a dual chamber pacemaker (5 year follow-up) “cured” her of further syncope. This is the 1st report of pacemaker use for this unusual form of reflex syncope.

Rytlewski, Jason A.; Lee, John T.; Raj, Satish R.

2013-01-01

315

Sleep syncope: treatment with a permanent pacemaker.  

PubMed

Vasovagal syncope usually occurs during upright posture, but Jardine et al. have described a variant that occurs at night. During "sleep syncope" patients are awakened from sleep with nausea, abdominal cramping, or a sense of impending diarrhea; get up; and faint in the bathroom. We report on a patient with recurrent sleep syncope (with physical injury) in whom an asystolic pause was documented during one of her "sleep syncope" spells. Implantation of a dual chamber pacemaker (5-year follow-up) "cured" her of further syncope. This is a report of pacemaker use for this unusual form of reflex syncope. PMID:22433038

Rytlewski, Jason A; Lee, John T; Raj, Satish R

2012-03-20

316

Transcription Factor RTEF-1 Mediates a1Adrenergic Reactivation of the Fetal Gene Program in Cardiac Myocytes  

Microsoft Academic Search

a1-Adrenergic receptor stimulation induces cardiac myocytes to hypertrophy and reactivates many fetal genes, including b-myosin heavy chain (bMyHC) and skeletal a-actin (SKA), by signaling through myocyte-specific CAT (M-CAT) cis elements, binding sites of the transcriptional enhancer factor-1 (TEF-1) family of transcription factors. To examine functional differences between TEF-1 and related to TEF-1 (RTEF-1) in a1-adrenergic reactivation of the fetal program,

Alexandre F. R. Stewart; Joseph Suzow; Toru Kubota; Takahisa Ueyama; Hsiao-Huei Chen

317

Steroid treatment of the painful pacemaker pocket.  

PubMed

Chronic pain about a pacemaker secondary to sterile fibrotic contracture of the capsule is an uncommon but frustrating complication for both the physician and the patient. Three cases of this complication controlled by the late injection of triamcinolone are reported. PMID:6199773

Kratz, J M; Campbell, W C; Leman, R B; Harvin, J S

1984-01-01

318

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

319

Endogenous fungal endophthalmitis after cardiac surgery.  

PubMed

The authors present a single-patient interventional case report of endogenous fungal endophthalmitis (EFE) in a patient with an implanted prosthetic device. A 74-year-old man underwent a double coronary artery bypass graft with a bioprosthetic pericardial valve and transvenous dual chamber pacemaker. Four months later, he presented with EFE. Despite aggressive local and systemic antifungal therapy, the patient died of septic shock due to a fungally infected pacemaker. Successful management of post-cardiac surgery EFE requires aggressive local and systemic antifungal therapy, but without surgical removal of implanted thoracic hardware these modalities alone may be insufficient for a cure. PMID:21053864

Saffra, Norman A; Desai, Rajen U; Seidman, Carly J; Chapnick, Edward K

2010-10-28

320

Measuring pacemaker dose: A clinical perspective  

SciTech Connect

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.

Studenski, Matthew T., E-mail: matthew.studenski@jeffersonhospital.org [Department of Radiation Oncology at the Jefferson Medical College and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA (United States); Xiao Ying; Harrison, Amy S. [Department of Radiation Oncology at the Jefferson Medical College and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA (United States)

2012-07-01

321

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

2011-08-27

322

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

PubMed

In spite of ethical analyses assimilating the palliative deactivation of pacemakers to commonly accepted withdrawings of life-sustaining therapy, many clinicians remain ethically uncomfortable with pacemaker deactivation at the end of life. Various reasons have been posited for this discomfort. Some cardiologists have suggested that reluctance to deactivate pacemakers may stem from a sense that the pacemaker has become part of the patient's "self." The authors suggest that Daniel Sulmasy is correct to contend that any such identification of the pacemaker is misguided. The authors argue that clinicians uncomfortable with pacemaker deactivation are nevertheless correct to see it as incompatible with the traditional medical ethics of withdrawal of support. Traditional medical ethics is presently taken by many to sanction pacemaker deactivation when such deactivation honors the patient's right to refuse treatment. The authors suggest that the right to refuse treatment applies to treatments involving ongoing physician agency. This right cannot underwrite patient demands that physicians reverse the effects of treatments previously administered, in which ongoing physician agency is no longer implicated. The permanently indwelling pacemaker is best seen as such a treatment. As such, its deactivation in the pacemaker-dependent patient is best seen not as withdrawal of support but as active ending of life. That being the case, clinicians adhering to the usual ethical analysis of withdrawal of support are correct to be uncomfortable with pacemaker deactivation at the end of life. PMID:22351107

Huddle, Thomas S; Amos Bailey, F

2012-12-01

323

[Two cases of depressive disorder after pacemaker implantation].  

PubMed

We report 2 patients who showed psychological symptoms after pacemaker implantation. Pacemaker syndrome was excluded, and a diagnosis of depressive disorder not otherwise specified was made in both patients. Patient 1 complained of discomfort early after pacemaker implantation but became unaware of the pacemaker after 1 year. However, after 3 years, lack of activity, general fatigue, and unaccountable sensations developed. These symptoms improved with symbiosis with the pacemaker. Patient 2 developed many complications after pacemaker implantation. Therefore, he was markedly aware of the pacemaker as not-self and wanted to remove it. One month after implantation, unaccountable sensations and irritations began to occur. He did not return to work, and the symptoms improved with progression of "mourning for the loss of the perfection of the own body". In both patients, their symptoms improved after "acceptance that their own body depended on the pacemaker" and "symbiosis with the pacemaker as not-self", not complete integration of the pacemaker. Therefore, the psychological process after pacemaker implantation consisted of the establishment of "mourning for the loss of the perfection of the own body" and "symbiosis with not-self". In these patients, this process was impaired, causing depressive symptoms. This process resembled the integration process in patients undergoing dialysis or renal transplantation. As, compared with renal transplantation, it is more difficult to integrate the pacemaker to the own body, so, it seems better to aim for "symbiosis with the pacemaker" to promote the adjustment process. To promote the adjustment process and decrease depression, support after understanding of this psychological process is needed. PMID:8552727

Tanaka, K

1995-01-01

324

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

PubMed

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

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

2012-12-24

325

[Another case of "Lazarus phenomenon" during surgery? Spontaneous return of circulation in a patient with a pacemaker].  

PubMed

A case is presented of spontaneous return of circulation after cardiac arrest in a patient with a pacemaker without intraoperative resuscitation. In the literature this kind of situation is called the Lazarus phenomenon. Cardiac arrest of the patient occurred during surgery and because of the poor prognosis no cardiopulmonary resuscitation was initiated. After 6 min of apnoea and cessation of circulation, the circulation restarted spontaneously and surgery was continued. Afterwards the patient was transferred to the intensive care unit but died 2 days later without regaining consciousness. The pathophysiological mechanisms for the Lazarus phenomenon are poorly understood but several mechanisms and multifactorial events are discussed in the literature. PMID:17898966

Wiese, C H R; Stojanovic, T; Klockgether-Radke, A; Bartels, U; Schmitto, J D; Quintel, M; Graf, B M

2007-12-01

326

Successful management of multiple permanent pacemaker complications - infection, 13 year old silent lead perforation and exteriorisation following failed percutaneous extraction, superior vena cava obstruction, tricuspid valve endocarditis, pulmonary embolism and prosthetic tricuspid valve thrombosis  

PubMed Central

A 59 year old man underwent mechanical tricuspid valve replacement and removal of pacemaker generator along with 4 pacemaker leads for pacemaker endocarditis and superior vena cava obstruction after an earlier percutaneous extraction had to be abandoned, 13 years ago, due to cardiac arrest, accompanied by silent, unsuspected right atrial perforation and exteriorisation of lead. Postoperative course was complicated by tricuspid valve thrombosis and secondary pulmonary embolism requiring TPA thrombolysis which was instantly successful. A review of literature of pacemaker endocarditis and tricuspid thrombosis along with the relevant management strategies is presented. We believe this case report is unusual on account of non operative management of right atrial lead perforation following an unsuccessful attempt at percutaneous removal of right sided infected pacemaker leads and the incidental discovery of the perforated lead 13 years later at sternotomy, presentation of pacemaker endocarditis with a massive load of vegetations along the entire pacemaker lead tract in superior vena cava, right atrial endocardium, tricuspid valve and right ventricular endocardium, leading to a functional and structural SVC obstruction, requirement of an unusually large dose of warfarin postoperatively occasioned, in all probability, by antibiotic drug interactions, presentation of tricuspid prosthetic valve thrombosis uniquely as vasovagal syncope and isolated hypoxia and near instantaneous resolution of tricuspid prosthetic valve thrombosis with Alteplase thrombolysis.

Kaul, Pankaj; Adluri, Krishna; Javangula, Kalyana; Baig, Wasir

2009-01-01

327

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

328

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

329

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

Federal Register 2010, 2011, 2012, 2013

...3610 Implantable pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a power supply and electronic circuits...any implantable pacemaker pulse generator device that was in...

2012-06-22

330

Self-Organized Stable Pacemakers near the Onset of Birhythmicity  

NASA Astrophysics Data System (ADS)

General amplitude equations are derived for reaction-diffusion systems near the soft onset of birhythmicity described by a supercritical pitchfork-Hopf bifurcation. Using these equations and applying singular perturbation theory, we show that stable autonomous pacemakers represent a generic kind of spatiotemporal patterns in such systems. This is verified by numerical simulations, which also show the existence of breathing and swinging pacemaker solutions. The drift of self-organized pacemakers in media with spatial parameter gradients is analytically and numerically investigated.

Stich, Michael; Ipsen, Mads; Mikhailov, Alexander S.

2001-05-01

331

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

PubMed

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

Garg, Naveen; Moorthy, Nagaraja

2012-12-01

332

Current status of pacemaker power sources.  

PubMed

After years during which pacers of very similar design and capabilities were provided by a small number of manufactures, many different lithium, halogen, rechargeable, and nuclear power sources are now available. The variety of chemistries, methods of construction, and sealing techniques used in the batteries of the different manufacturers is almost unlimited. This has made it necessary for physicians who implant and follow pacer to acquire a general knowledge of the field if they are to make an informed choice of pacemaker power source for implantation and if they are to manage recalls with a minimum of patient and physician trauma. More experience is required before it can be definitely determined which of the new pacer power sources will prove superior, but when coupled with well-designed, hermetically sealed pulse generators, all are capable of providing continuous pacing for at least 5 years and the 10-year pacemaker is now a probability. PMID:655753

Tyers, G F; Brownlee, R R

1978-06-01

333

[Permanent pacemaker implantation. Indications and results].  

PubMed

Clinical, laboratory and electrocardiographic data from 608 patients with permanent pacemakers implanted over a period of 8 years, were evaluated retrospectively. The number of implants was greater in males (56.5%) and in patients over 60 years of age (77.5%). Atherosclerosis was the most common disease found in this group (50%). Syncope occurred in 96.2% of the cases; and complete AV block was the most common electrocardiographic alteration (50.5%). Electrode displacement occurred in 32 patients (5.2%) and was the most commonly found early complication. Among the late complications, 10.3% of the patients had infections in the area of the generator. The total mortality was 7.7% due to the heart disease rather than pacemaker-related complication. PMID:2344227

Gutiérrez, A; Iturralde, P; Gutiérrez Fuster, E; Martínez Ríos, N; Martínez Ríos, M A; Romero, L; Hernández, D; González Hermosillo, J A

334

21 CFR 870.3640 - Indirect pacemaker generator function analyzer.  

Code of Federal Regulations, 2013 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3640 Indirect pacemaker generator function analyzer. (a) Identification. An indirect...

2013-04-01

335

[Inquiry of the Swiss Cardiology Society on long-term pacemakers in Switzerland in 1976 and 1977].  

PubMed

The Swiss Society of Cardiology has conducted a national inquiry into the state of pacing in Switzerland for the years 1976 and 1977. With a total of 1250 pacemakers implanted each year and a rate of first implantation of 146 per year and per million inhabitants, this study illustrates the methods of Swiss cardiologists and the problems which they meet in the field. It is generally agreed, as in other countries, that stimulation of the right ventricle by endocavitary approach with demand pacemakers generated by lithium batteries appears to be excellent for the moment. Pacemakers which can be programmed were not in widespread use during the period of this study. The incidence of various complications is considered. PMID:432610

Jaeger, M

1979-02-17

336

Proposed diagnostic reference levels for 3 common cardiac interventional procedures in Ireland  

Microsoft Academic Search

Radiation doses for 3 common types of cardiac radiological examinations where investigated: coronary angiography (CA), percutaneous coronary intervention (PCI) and pacemaker insertions (PPI). 22 cardiac imaging suites participated in the study. Radiation dose was monitored for 1804 adult patients using dose area product (DAP) meters. Operational and examination details such as cardiologist grade, patient details and examination complexity were recorded

C. D'Helft; A. M. McGee; L. A. Rainford; S. L. Mc Fadden; C. M. Hughes; R. J. Winder; P. C. Brennan

2007-01-01

337

Psychological Factors and Cardiac Risk And Impact of Exercise Training Programs--A Review of Ochsner Studies  

PubMed Central

Although under-emphasized, substantial evidence indicates that psychological distress, especially depression, hostility, and anxiety, are risk factors for coronary heart disease (CHD) and affect recovery following major coronary heart disease events. We review several major studies from Ochsner Medical Center demonstrating the high prevalence of psychological distress in CHD patients and the marked benefits that occur following formal cardiac rehabilitation and exercise training programs. These benefits include reductions in psychological stress, improvements in CHD risk factors that accompany high stress, and reduced all-cause mortality. These data support the benefits of exercise training and increased levels of fitness to improve psychological stress and subsequent prognosis.

Lavie, Carl J.; Milani, Richard V.; Artham, Surya M.; Gilliland, Yvonne

2007-01-01

338

A new view of an unusual pacemaker complication: role of three-dimensional transthoracic echocardiography.  

PubMed

Tricuspid regurgitation (TR) produced by endocavitary leads (EL) from permanent pacemakers and implantable cardiac defibrillators is a well-known complication of this procedure. The EL may damage or interfere with tricuspid valve function causing mechanical interference of the valve leaflets leading to incomplete valve closure. It is important to recognize this mechanical complication because it could be corrected by repositioning the lead. In this case report we demonstrate how three-dimensional transthoracic echocardiography permits to obtaining an en face view, which allows simultaneous visualization of the 3 moving leaflets during the cardiac cycle, their attachment to the tricuspid annulus and the pattern of leaflet coaptation. Thus, we propose three-dimensional transthoracic echocardiography as the tool of choice to evaluate TR related to EL, to evaluate the necessity of repositioning the lead if severe regurgitation or tricuspid valve malfunction are demonstrated. PMID:23551119

Miglioranza, Marcelo Haertel; Becker, Derly; Jiménez-Nácher, José-Julio; Moya, José Luis; Golfin, Covadonga Fernandez; Zamorano, José Luis

2013-04-01

339

[Effectiveness of long-term treatment with vasodilators in patients with artificial pacemakers].  

PubMed

The effect of long-term use of venular and arterial vasodilators (molsidomin and nifedipin) on the clinical course and hemodynamic indices was studied in 52 patients with artificial pacemakers. The choice of vasodilator was based on an acute drug test. In the presence of hypertensive disease the calcium antagonist nifedipin was used, in cases of dilatation of the cardiac compartments molsidomin was used. Combination of both drugs was used in patients in whom the acute drug test did not allow to prefer any of the drugs. It is concluded that three-month's treatment resulted in positive changes of the hemodynamics, reduction of the severity of cardiac insufficiency. Side-effects were practically absent. PMID:1891849

Xalifa, S; Berezov, V M

1991-06-01

340

Investigation of the bnp level changes in blood stream in different modes and lead locations after pacemaker implementation.  

PubMed

As has been proven, increase of mechanical strain could result in an increase of brain natriuretic peptide (BNP) in the blood stream of implanted patient pacemakers. We measured the BNP concentration in blood due to different mode and lead implantation location of pacemaker in the time period of 3 months. The aim of this study was to investigate the changing trend of BNP level after pacemaker implantation. One hundred and three pacemaker implanted patients were monitored. Patients were in the age span of 54±12 years, including 48 men and 55 women. A group of 44 were programmed in Dual Chamber Rate Adaptive (DDDR) Pacemaker mode and a group of 59 were programmed in Ventricular Rate Modulated Pacing (VVIR) mode by the recommendation of the cardiologist. Between these two groups, the pacing levels of pacemakers was divided to under and above 50%. Some of these pacemaker leads were located at the apex of the right ventricle and the others were located in the septum wall in the right ventricle. To evaluate BNP changes during a period of 3 months, the BNPs were measured in pg/ml within 24 h of implantation (BNP1) and after 3 months (BNP2). For different classes of pacemaker implantations, the ratio of final measurement (BNP2) is divided to after implantation measurements (BNP1). Results showed that in VVIR mode, the ratio is 1.54±0.3 and in DDDR mode, the ratio is 0.38±0.17, with acceptable standard error means (<0.04). Also, comparisons are made for lead location at two modes of DDDR and VVIR separately. In the DDDR mode, the ratio for apex location is 0.49±0.12 and for septum location is 0.22±0.34, with acceptable standard error means (<0.02). In the VVIR mode, the ratio for apex location is 1.71±0.27 and for septum location is 1.28±0.09, with acceptable standard error means (<0.04). Therefore, BNP decrease in DDDR mode is more than in VVIR mode programming. In both cases of DDDR and VVIR modes, the septum location of the leads would result in a greater decrease of BNP. PMID:23492826

Dehnavi, Alireza Mehri; Fakhrpour, Afshin; Tavakoli, Mohamad Bagher; Nikoo, Mohamad Hossein

2012-01-01

341

Stopping the Circadian Pacemaker with Inhibitors of Protein Synthesis  

Microsoft Academic Search

The requirement for protein synthesis in the mechanism of a circadian pacemaker was investigated by using inhibitors of protein synthesis. Continuous treatment of the ocular circadian pacemaker of the molluse Bulla gouldiana with anisomycin or cycloheximide substantially lengthened (up to 39 and 52 hr, respectively) the free-running period of the rhythm. To determine whether high concentrations of inhibitor could stop

Sat Bir S. Khalsa; David Whitmore; Gene D. Block

1992-01-01

342

Spontaneous Activity in Isolated Somata of Aplysia Pacemaker Neurons  

Microsoft Academic Search

Somata of pacemaker and nonpacemaker neurons were isolated by ligatures tied around the axons between the somata and the synaptic regions, and the transmembrane potentials of the isolated somata were recorded. Iso- lated somata of pacemaker neurons had a spontaneous discharge while isolated somata of nonpacemaker neurons were quiescent. In addition, the time course of accommodation in isolated somata of

BARBARA O. ALVING

1968-01-01

343

Development of an external demand pacemaker evaluation system  

Microsoft Academic Search

An external-pacemaker-testing protocol has been established that has improved the quality of patient safety. Fabrication of an external demand pacemaker test device permits a quick check for compliance with specifications recommended by the manufacturer and Emergency Care Research Institute (ECRI). This test device, including the fabrication and necessary documentation, is explained. The electronic design is modular, and therefore implementation of

D. J. Coiro

1988-01-01

344

Initial experience with a physiological, rate responsive pacemaker  

Microsoft Academic Search

A new pacemaker that can adapt the heart rate in response to the patient's metabolic requirements has been developed. This pacemaker uses the QT interval as the indicator of physiological demand. Experience in five patients showed the rate response to exercise to be smooth and progressive and to return gradually to the basic paced rate after activity stopped. Physiological rate

R M Donaldson; K Fox; A F Rickards

1983-01-01

345

Rectosigmoid Pacemaker: Role in Defecation Mechanism and Constipation  

Microsoft Academic Search

The possible existence of a ‘pacemaker’ at the rectosigmoid junction (RSJ) was studied in 26 normal volunteers, 16 constipated subjects, 6 patients with anterior resection for rectal cancer and 8 during operative interference. The effectiveness of an artificial pacemaker (AP) in the treatment of 26 chronic constipated patients was also investigated. In normal subjects, the passage of an inflated condom

Ahmed Shafik

1993-01-01

346

Realistic modelling of interference in pacemakers by ELF magnetic fields  

Microsoft Academic Search

Many experimental studies gave different proofs on the pacemaker's susceptibility by ELF magnetic fields, nevertheless it's still difficult to trace currents and voltages that invade the pacemaker input stage, determining in this way anomalies in the implantable device. Luckily, modern computational resources, joined to the detailed conductivity models of human body, with a precision of the fraction of millimeter, make

Antonio Augello; Roberto De Leo; Franco Moglie

2005-01-01

347

Effect of an irregular ventricular rhythm on cardiac output  

Microsoft Academic Search

The results of this study suggest that a third mechanism for the reduction of cardiac output in patients with AF is irregularity of the ventricular rhythm. Catheter ablation of the AV junction and implantation of a rate-responsive pacemaker in patients with AF may offer hemodynamic benefit beyond rate control by eliminating the irregularity that is present with medical therapy or

Emile G. Daoud; Raul Weiss; Marwan Bahu; Bradley P. Knight; Frank Bogun; Rajiva Goyal; Mark Harvey; S. Adam Strickberger; K. Ching Man; Fred Morady

1996-01-01

348

Respiratory and cardiac abnormalities in brain-stem ischaemia  

Microsoft Academic Search

Two patients are presented who had suffered episodes of ischaemia of the brain-stem, mainly affecting one side of the pons. In addition to the more usual neurological signs, these two patients had cardiac arrhythmia: one had a sinus arrhythmia, the other a wandering pacemaker. In both patients the hemidiaphragm on the side ipsilateral to the lesion was transiently elevated. The

A D Korczyn

1975-01-01

349

[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

350

Pre-ejection period by radial artery tonometry supplements echo doppler findings during biventricular pacemaker optimization  

PubMed Central

Background Biventricular (Biv) pacemaker echo optimization has been shown to improve cardiac output however is not routinely used due to its complexity. We investigated the role of a simple method involving computerized pre-ejection time (PEP) assessment by radial artery tonometry in guiding Biv pacemaker optimization. Methods Blinded echo and radial artery tonometry were performed simultaneously in 37 patients, age 69.1 ± 12.8 years, left ventricular (LV) ejection fraction (EF) 33 ± 10%, during Biv pacemaker optimization. Effect of optimization on echo derived velocity time integral (VTI), ejection time (ET), myocardial performance index (MPI), radial artery tonometry derived PEP and echo-radial artery tonometry derived PEP/VTI and PEP/ET indices was evaluated. Results Significant improvement post optimization was achieved in LV ET (286.9 ± 37.3 to 299 ± 34.6 ms, p < 0.001), LV VTI (15.9 ± 4.8 cm to 18.4 ± 5.1 cm, p < 0.001) and MPI (0.57 ± 0.2 to 0.45 ± 0.13, p < 0.001) and in PEP (246.7 ± 36.1 ms to 234.7 ± 35.5 ms, p = 0.003), PEP/ET (0.88 ± 0.21 to 0.79 ± 0.17, p < 0.001), and PEP/VTI (17.3 ± 7 to 13.78 ± 4.7, p < 0.001). The correlation between comprehensive echo Doppler and radial artery tonometry-PEP guided optimal atrioventricular delay (AVD) and optimal interventricular delay (VVD) was 0.75 (p < 0.001) and 0.69 (p < 0.001) respectively. In 29 patients with follow up assessment, New York Heart Association (NYHA) class reduced from 2.5 ± 0.8 to 2.0 ± 0.9 (p = 0.004) at 1.8 ± 1.4 months. Conclusion An acute shortening of PEP by radial artery tonometry occurs post Biv pacemaker optimization and correlates with improvement in hemodynamics by echo Doppler and may provide a cost-efficient approach to assist with Biv pacemaker echo optimization.

2011-01-01

351

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

Microsoft Academic Search

Summary  The cardiac dimensions of male long-distance runners (LDR) and cycle racers (CR) were determined echocardiographically during\\u000a four different training seasons, i.e., a preparation, a competitive, a slowing-down and a resting season, and were compared\\u000a with those of control subjects (CS). Left ventricular hypertrophy (LVH) was also assessed from the electrocardiogram. The\\u000a maximal aerobic performance was determined on a bicycle ergometer.

L. H. E. H. Snoeckx; H. F. M. Abeling; J. A. C. Lambregts; J. J. F. Schmitz; F. T. J. Verstappen; R. S. Reneman

1983-01-01

352

Cardiac stem cells differentiate into sinus node-like cells.  

PubMed

The advent of stem cell therapy brings about the hope to restore the loss of cardiac pacemaker cells. However, it is largely unknown whether cardiac stem cells are able to differentiate into pacemaker cells. The purpose of this study was to determine whether the heart of large juvenile mammals contains cardiac stem cells (CSCs), which are suitable as seed cells for restoration of cardiac pacemaker cell. The c-kit(+) CSCs were isolated from one-month-old mongrel dogs. CSCs that we sorted were self-renewing, and they could proliferate by clonal expansion. CSCs could differentiate into cardiac muscle, smooth muscle and endothelial cells at rates of 10.5 ± 4.2%, 13.5 ± 5.1% and 12.9 ± 3.5%, respectively, at week 4, as judged by the expression of respective differentiation markers: cardiac troponin I, smooth muscle actin, and CD31. At week 8, the differentiation rates were further increased to 23.2 ± 3.6%, 25.9 ± 6.6% and 28.3 ± 6.1% (P < 0.05 for each marker). Some of cells derived from CSCs could express cardiac transcription factor GATA-4 after week 2 and express pacing-related genes, including hyperpolarization-activated cyclic nucleotide-gated 2 (HCN2) and HCN4 after week 4. Importantly, a fraction of CSCs demonstrated the presence of inward currents that indicate the expression of inward current channels. In conclusion, c-kit(+) CSCs may differentiate into cardiac muscle cell and sinus node-like cells, suggesting that CSCs would be useful as seed cells in treating sinus bradycardiac disorders or exploring the mechanism of pacemaker activity. PMID:20877167

Zhang, Jun; Huang, Congxin; Wu, Pan; Yang, Jing; Song, Tao; Chen, Yongjun; Fan, Xinrong; Wang, Ten

2010-10-01

353

In-vitro mapping of E-fields induced near pacemaker leads by simulated MR gradient fields  

PubMed Central

Background Magnetic resonance imaging (MRI) of patients with implanted cardiac pacemakers is generally contraindicated but some clinicians condone scanning certain patients. We assessed the risk of inducing unintended cardiac stimulation by measuring electric fields (E) induced near lead tips by a simulated MRI gradient system. The objectives of this study are to map magnetically induced E near distal tips of leads in a saline tank to determine the spatial distribution and magnitude of E and compare them with E induced by a pacemaker pulse generator (PG). Methods We mapped magnetically induced E with 0.1 mm resolution as close as 1 mm from lead tips. We used probes with two straight electrodes (e.g. wire diameter of 0.2 mm separated by 0.9 mm). We generated magnetic flux density (B) with a Helmholtz coil throughout 0.6% saline in a 24 cm diameter tank with (dB/dt) of 1 T/sec (1 kHz sinusoidal waveform). Separately, we measured E near the tip of leads when connected to a PG set to a unipolar mode. Measurements were non-invasive (not altering the leads or PG under study). Results When scaled to 30 T/s (a clinically relevant value), magnetically-induced E exceeded the E produced by a PG. The magnetically-induced E only occurred when B was coincident with or within 15 msec of implantable pacemaker's pulse. Conclusions Potentially hazardous situations are possible during an MR scan due to gradient fields. Unintended stimulation can be induced via abandoned leads and leads connected to a pulse generator with loss of hermetic seal at the connector. Also, pacemaker-dependent patients can receive drastically altered pacing pulses.

2009-01-01

354

Asynchronous response of coupled pacemaker neurons  

PubMed Central

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

Dodla, Ramana; Wilson, Charles J.

2009-01-01

355

Hybrid segmentation of left ventricle in cardiac MRI using Gaussian-mixture model and region restricted dynamic programming.  

PubMed

Segmentation of the left ventricle from cardiac magnetic resonance images (MRI) is very important to quantitatively analyze global and regional cardiac function. The aim of this study is to develop a novel and robust algorithm which can improve the accuracy of automatic left ventricle segmentation on short-axis cardiac MRI. The database used in this study consists of three data sets obtained from the Sunnybrook Health Sciences Centre. Each data set contains 15 cases (4 ischemic heart failures, 4 non-ischemic heart failures, 4 left ventricle (LV) hypertrophies and 3 normal cases). Three key techniques are developed in this segmentation algorithm: (1) ray scanning approach is designed for segmentation of images with left ventricular outflow tract (LVOT), (2) a region restricted technique is employed for epicardial contour extraction, and (3) an edge map with non-maxima gradient suppression approach is put forward to improve the dynamic programming to derive the epicardial boundary. The validation experiments were performed on a pool of data sets of 45 cases. For both endo- and epi-cardial contours of our results, percentage of good contours is about 91%, the average perpendicular distance is about 2mm. The overlapping dice metric is about 0.92. The regression and determination coefficient between the experts and our proposed method on the ejection fraction (EF) is 1.01 and 0.9375, respectively; they are 0.9 and 0.8245 for LV mass. The proposed segmentation method shows the better performance and is very promising in improving the accuracy of computer-aided diagnosis systems in cardiovascular diseases. PMID:23245907

Hu, Huaifei; Liu, Haihua; Gao, Zhiyong; Huang, Lu

2012-12-14

356

Cardiac specialty program for home health care: A model for implementation  

Microsoft Academic Search

A new trend is emerging in home health care—specialty programs. With the emphasis on dis ease management, home health agencies must develop programs that focus on specific patient groups with similar diagnoses or problems. Health care providers, such as managed care compa nies, demand better patient outcomes. Specialty programs target specific populations by using advance practice personnel as primary caregivers

Margaline Lazarre; Sally Ax

1995-01-01

357

Firing Patterns and Transitions in Coupled Neurons Controlled by a Pacemaker  

NASA Astrophysics Data System (ADS)

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

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

2008-08-01

358

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

PubMed Central

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

Luna-Zurita, Luis; Prados, Belen; Grego-Bessa, Joaquim; Luxan, Guillermo; del Monte, Gonzalo; Benguria, Alberto; Adams, Ralf H.; Perez-Pomares, Jose Maria; de la Pompa, Jose Luis

2010-01-01

359

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

PubMed

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

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

1999-05-01

360

Physical Therapists as Providers of Care: Exercise Prescriptions and Resultant Outcomes in Cardiac and Pulmonary Rehabilitation Programs in New York State  

Microsoft Academic Search

Purpose: Physical therapists have engaged in cardiac rehabilitation (CR) and pulmonary rehabilitation (PR) for decades, but the extent of their current involvement in this practice area is unclear. This study surveyed directors of CR and PR programs on a statewide level to ascertain what type of provider is writing the prescription, which methods of exercise formulation are used, which outcome

William E. DeTurk; Lisa Benz Scott

2008-01-01

361

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

362

Biodegradation of polyether polyurethane inner insulation in bipolar pacemaker leads.  

PubMed

Several bipolar coaxial pacemaker leads, composed of an outer silicone rubber insulation and an inner polyether polyurethane (PEU) insulation, which were explanted due to clinical evidence of electrical dysfunction, were analyzed in this study. Optical microscopy (OM) and scanning electron microscopy (SEM) were used to determine the cause of failure. Attenuated total reflectance-Fourier transform infrared microscopy (ATR-FTIR) was used to analyze the PEU insulation for chemical degradation. In all leads, the silicone rubber outer insulation showed no signs of physical damage. Physical damage to the inner PEU insulation was the source of electrical dysfunction. Cracks through the PEU compromised the insulation between the inner and outer conductor coils in the lead. It was observed with SEM that these cracks originated on the outer surface of the inner insulation and progressed inward. ATR-FTIR analysis showed that the PEU had chemically degraded via oxidation of the ether soft segment. Furthermore, it was revealed that chemical degradation was more advanced on the outer surface of the PEU. It was hypothesized that hydrogen peroxide permeated through the outer silicone insulation and decomposed into hydroxyl radicals that caused the chemical degradation of PEU. The metal in the outer conductor coil catalyzed the decomposition of the hydrogen peroxide. Chemical degradation of the PEU could also have been catalyzed by metal ions created from the corrosion of the metal in the outer conductor coil by hydrogen peroxide. Physical damage probably occurred in regions of the leads that were subjected to a higher hydrogen peroxide concentration from inflammatory cells and high degrees and rates of strain due to intercorporeal movement, including, but not limited to, cardiac movement. Chemical degradation and physical damage probably had a synergistic affect on failure of the insulation, in that as chemical degradation proceeded, the polymer surface became brittle and more susceptible to physical damage. As physical damage proceeded, cracks propagated into the unaffected bulk, exposing it to oxidants. PMID:11319745

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

2001-05-01

363

Selective pharmacological inhibition of the pacemaker channel isoforms (HCN1-4) as new possible therapeutical targets.  

PubMed

The pacemaker channel isoforms are encoded by the hyperpolarization-activated and cyclic nucleotide-gated (HCN) gene family and are responsible for diverse cellular functions including regulation of spontaneous activity in sino-atrial node cells and control of excitability in different types of neurons. Four channel isoforms exist (HCN1-HCN4). The hyperpolarization-activated cardiac pacemaker current (I(f)) has an important role in the generation of the diastolic depolarization in the sino-atrial node, while its neuronal equivalent (I(h)) is an important contributor to determination of resting membrane potential, and plays an important role in neuronal functions such as synaptic transmission, motor learning and generation of thalamic rhythms. Ivabradine is a novel, heart rate-lowering drug which inhibits the pacemaker (I(f)) current in the heart with high selectivity and with minimal effect on haemodynamic parameters. Ivabradine is beneficial in patients with chronic stable angina pectoris equally to beta receptor blocker and calcium channel antagonist drugs. There is increasing interest to apply this drug in other fields of cardiology such as heart failure, myocardial infarction, cardiac arrhyhtmias. Heart rate reduction might improve clinical outcomes in heart failure. HCN upregulation presumably contributes to increased (I(f)) and may play a role in ventricular and atrial arrhythmogenesis in heart failure. In the nervous system the HCN channels received attention in the research areas of neuropathic pain, epilepsy and understanding the mechanism of action of volatile anaesthetics. This article delineates that the pharmacological modulation of cardiac and neuronal HCN channels can serve current or future drug therapy and introduces some recently investigated HCN channel inhibitor compounds being potential candidates for development. PMID:21774761

Koncz, I; Szél, T; Jaeger, K; Baczkó, I; Cerbai, E; Romanelli, M N; Gy Papp, J; Varró, A

2011-01-01

364

[{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

365

[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

366

Efficacy and safety of bipolar sensing with high atrial sensitivity in dual chamber pacemakers.  

PubMed

In dual chamber pacemakers, atrial sensing performance is decisive for maintenance of AV synchrony. Particularly, the efficacy of mode switching algorithms during intermittent atrial tachyarrhythmias depends on the sensitive detection of low potential amplitudes. Therefore, a high atrial sensitivity of 0.18 mV, commonly used in single lead VDD pacemakers, was investigated for its efficacy and safety in DDD pacing. Thirty patients received dual chamber pacemakers and bipolar atrial screw-in leads for sinus node syndrome or AV block; 15 patients suffered from intermittent atrial fibrillation. Pace makers were programmed to an atrial sensitivity of 0.18 mV. Two weeks, 3, 9, and 15 months after implantation, P wave sensing threshold and T wave oversensing thresholds for the native and paced T wave were determined. The myopotential oversensing thresholds were evaluated by isometric contraction of the pectoral muscles. Automatic mode switch to DDIR pacing was activated when the mean atrial rate exceeded 180 beats/min. The patients were followed by 24-hour Holter monitoring. Two weeks after implantation, mean atrial sensing threshold was 1.81 +/- 0.85 mV (range 0.25-2.8 mV) without significant differences during further follow-up. Native T wave sensing threshold was < 0.18 mV in all patients. In 13% of patients, paced T waves were perceived in the atrial channel at the highest sensitivity. This T wave sensing could easily be avoided by programming a postventricular atrial refractory period exceeding 300 ms. Myopotential oversensing could not be provoked and Holter records showed no signs of sensing dysfunction. During a 15-month follow-up, 1,191 mode switch events were counted by autodiagnostic pacemaker function. Forty-two of these events occurred during Holter monitoring. Unjustified mode switch was not observed. In DDD pacemakers, bipolar atrial sensing with a very high sensitivity is efficient and safe. Using these sensitivity settings, activation of the mode switch algorithm almost completely avoids fast transmission of atrial rate to the ventricle during atrial fibrillation. PMID:10793429

Wiegand, U K; Bode, F; Peters, W; Haase, H; Bonnemeier, H; Katus, H A; Potratz, J

2000-04-01

367

Stopping the circadian pacemaker with inhibitors of protein synthesis.  

PubMed Central

The requirement for protein synthesis in the mechanism of a circadian pacemaker was investigated by using inhibitors of protein synthesis. Continuous treatment of the ocular circadian pacemaker of the mollusc Bulla gouldiana with anisomycin or cycloheximide substantially lengthened (up to 39 and 52 hr, respectively) the free-running period of the rhythm. To determine whether high concentrations of inhibitor could stop the pacemaker, long pulse treatments of various durations (up to 44 hr) were applied and the subsequent phase of the rhythm was assayed. The observed phases of the rhythm after the treatments were a function of the time of the end of the treatment pulse, but only for treatments which spanned subjective dawn. The results provide evidence that protein synthesis is required in a phase-dependent manner for motion of the circadian pacemaker to continue. Images

Khalsa, S B; Whitmore, D; Block, G D

1992-01-01

368

Pacemakers in a Reaction-Diffusion Mechanics System  

NASA Astrophysics Data System (ADS)

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

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

2007-07-01

369

Pacemaker activity in the insect (T. molitor) heart: role of the sarcoplasmic reticulum.  

PubMed

The electrophysiological properties of the myogenic cardiac cells of insects have been analyzed, but the mechanisms that regulate the pacemaker activity have not been elucidated yet. In mammalian pacemaker cells, different types of membrane ion channels seem to be sequentially activated, perhaps in a cooperative fashion with the current generated by Ca(2+) extrusion mediated by the electrogenic Na(+)/Ca(2+) exchanger, which is sustained by the diastolic sarcoplasmic reticulum (SR) Ca(2+) release. The objective of the present work was to investigate the role of the SR function on the basal beating rate (BR), and BR modulation by extracellular Ca(2+) concentration ([Ca(2+)](o)) and neurotransmitters in the in situ dorsal vessel (heart) of the mealworm beetle Tenebrio molitor. The main observations were as follows: 1) basal BR was reduced by 50% by inhibition of SR function, but not affected by perfusion with CsCl or ZD7288; 2) spontaneous activity was abolished by Cd(2+); 3) a robust positive chronotropic response could be elicited to serotonin (5-HT), but not to norepinephrine or carbamylcholine; 4) SR inhibition abolished the sustained chronotropic stimulation by [Ca(2+)](o) elevation and by 5-HT, while the latter was unaffected by CsCl. It is concluded that, in T. molitor heart, BR is markedly, but not exclusively, dependent on the SR function, and that BR control and modulation by both [Ca(2+)](o) and 5-HT requires a functional SR. PMID:21917905

Feliciano, Danielle F; Bassani, Rosana A; Oliveira, Pedro X; Bassani, José W M

2011-09-14

370

Venous obstruction in permanent pacemaker patients: an isotopic study  

SciTech Connect

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

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

1981-01-01

371

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

372

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

373

Developmental changes in pacemaker currents in mouse locus coeruleus neurons  

Microsoft Academic Search

The present study compares the electrophysiological properties and the primary pacemaker currents that flow during the interspike interval in locus coeruleus (LC) neurons from infant (P7–12days) and young adult (8–12weeks) mice. The magnitude of the primary pacemaker currents, which consist of an excitatory TTX-sensitive Na+ current and an inhibitory voltage-dependent K+ current, increased in parallel during development. We found no

Ramatis B. de Oliveira; Fernanda S. Gravina; Rebecca Lim; Alan M. Brichta; Robert J. Callister; Dirk F. van Helden

374

Organization and development of pacemaker of the gastrointestinal tract  

Microsoft Academic Search

Rhythmical depolarization and automatic contractions of smooth musculature of the gastrointestinal tract are a consequence\\u000a of pacemaker activity of c-Kit-immunoreactive cells of mesenchymal origin—interstitial Cajal cells (ICC) that have a peculiar\\u000a mechanism of intercellular Ca2+ balance, which is controlled by mitochondria. Intermuscular layer cells (ICC-MY) generate pacemaker potentials. Their induced\\u000a depolarization is enhanced by unitary potentials generated by intracellular population—ICC-IM.

A. V. Bursian

2008-01-01

375

Cardiovascular magnetic resonance with an MR compatible pacemaker  

PubMed Central

Magnetic resonance imaging (MRI) within FDA guidelines for the MRI-conditional pacemaker precludes placing the heart at the center of the magnet’s bore. This in effect appears to preclude cardiovascular MR. In this manuscript, we describe a protocol for cardiovascular MR of patients with a Revo pacemaker system while operating within FDA guidelines, and the first US case of cardiovascular MR in a patient with a Revo MRI-conditional pacing system despite position constraints.

2013-01-01

376

Pacemaker activity and ionic currents in mouse atrioventricular node cells  

PubMed Central

It is well established that pacemaker activity of the sino-atrial node (SAN) initiates the heartbeat. However, the atrioventricular node (AVN) can generate viable pacemaker activity in case of SAN failure, but we have limited knowledge of the ionic bases of AVN automaticity. We characterized pacemaker activity and ionic currents in automatic myocytes of the mouse AVN. Pacemaking of AVN cells (AVNCs) was lower than that of SAN pacemaker cells (SANCs), both in control conditions and upon perfusion of isoproterenol (ISO). Block of INa by tetrodotoxin (TTX) or of ICa,L by isradipine abolished AVNCs pacemaker activity. TTX-resistant (INar) and TTX-sensitive (INas) Na+ currents were recorded in mouse AVNCs, as well as T-(ICa,T) and L-type (ICa,L) Ca2+ currents. ICa,L density was lower than in SANCs (51%). The density of the hyperpolarization-activated current, (If) and that of the fast component of the delayed rectifier current (IKr) were, respectively, lower (52%) and higher (53%) in AVNCs than in SANCs. Pharmacological inhibition of If by 3 µM ZD-7228 reduced pacemaker activity by 16%, suggesting a relevant role for If in AVNCs automaticity. Some AVNCs expressed also moderate densities of the transient outward K+ current (Ito). In contrast, no detectable slow component of the delayed rectifier current (IKs) could be recorded in AVNCs. The lower densities of If and ICa,L, as well as higher expression of IKr in AVNCs than in SANCs may contribute to the intrinsically slower AVNCs pacemaking than that of SANCs.

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

2011-01-01

377

Pacemaker interference by magnetic fields at power line frequencies  

Microsoft Academic Search

Human exposure to external 50\\/60-Hz electric and magnetic fields induces electric fields within the body. These induced fields can cause interference with implanted pacemakers. In the case of exposure to magnetic fields, the pacemaker leads are subject to induced electromotive forces, with current return paths being provided by the conducting body tissues. Modern computing resources used in conjunction with millimeter-scale

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

2002-01-01

378

Clinical Aviation Medicine: A Physical-Conditioning Program for Cardiac Patients - a Progress Report.  

National Technical Information Service (NTIS)

Twenty men with well-documented episodes of myocardial infarction participated in a physical-conditioning program for 3 months or longer during the past 2 years. The activity consisted of intermittent jogging, calesthenics, and competitive games conducted...

J. Naughton M. T. Lategola K. Shanbour

1966-01-01

379

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

PubMed

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

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

2010-08-26

380

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

381

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

382

Undesirable mode switching with a dual chamber rate responsive pacemaker.  

PubMed

The Telectronics 1250 Meta MV DDDR pacemaker is a new device featuring automatic mode switching from DDDR to VVIR pacing in the event of an atrial arrhythmia. Although mode switching is a valuable feature, sinus tachycardia can cause an undesirable mode switch to occur. Of 24 implants at this institution, 11 have been for an AV conduction disorder. Eight of these 11 patients were specifically evaluated for undesirable mode switching. During exercise testing and/or Holter monitoring, mode switching was repeatedly seen in seven of the eight at low levels of exercise. Factors precipitating mode switching were a low rate response factor, low upper rate setting, long base postventricular atrial refractory period (PVARP) and a long AV delay. During Holter monitoring, patients spent up to 50% of the time in VVIR pacing as opposed to DDDR pacing. It is concluded that patients with intact sinus node function are at risk of undesirable mode switching and should probably be programmed to the DDD mode unless there is a specific indication for DDDR pacing. If the DDDR mode is chosen, careful selection of the aforementioned pacing parameters is required. PMID:7683799

Pitney, M R; May, C D; Davis, M J

1993-04-01

383

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

2013-06-27

384

[Atrial sensing and atrioventricular synchrony in single lead VDD pacemakers. Can the appearance of atrial undersensing be predicted?].  

PubMed

Single-lead VDD-pacing is an alternative to DDD-systems in patients with AV-block and normal sinus node function. Atrial sensing plays a central role in these pacemakers. AV-synchrony, incidence of atrial arrhythmias and the occurrence of sinus node disease were investigated in 108 patients with VDD-pacemakers followed over a mean period of 24.8 months after implantation. Determinants influencing the occurrence of atrial undersensing were especially focused on. Mean atrial potential and sensing threshold were reduced within the first 2 weeks after implantation (p < 0.01). Intermittent atrial undersensing occurred in 25.9% of patients and was observed in 82.1% of these patients within the first 2 weeks after implantation. Positioning the atrial dipole in the low right atrium showed a significantly higher incidence of atrial undersensing (42% in comparison to 24% in the other positions). In a multivariate analysis including intra- and postoperative measurements as well as characteristics of the pacemakers and leads, it was the only parameter significantly (p < 0.02) correlated to the occurrence of atrial undersensing. Atrial fibrillation was observed in 4.6% of patients, a sinus node disease became evident in 2.7% of patients; 92.6% of patients remained in the AV-synchronous mode. Intermittent atrial undersensing is common in single-lead VDD-pacemakers and difficult to provide during implantation. The atrial dipole should not be positioned in the low right atrium and highest atrial sensitivity should generally be programmed. Nevertheless, VDD-pacing achieves an AV-synchrony comparable to DDD-pacemakers. PMID:9173703

Wiegand, U K; Schneider, R; Bode, F; Brandes, A; Taubert, G; Potratz, J

1997-02-01

385

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

PubMed

Advanced cardiac life support (ACLS) is a problem-based course that employs simulation techniques to teach the standard management techniques of cardiovascular emergencies. Its structure is periodically revised according to new versions of the American Heart Association guidelines. Since it was introduced in Brazil in 1996, the ACLS has been through two conceptual and structural changes. Detailed documented reports on the effect of these changes on student performance are limited. The objective of the present study was to evaluate the effect of conceptual and structural changes of the course on student ACLS performance at a Brazilian training center. This was a retrospective study of 3266 students divided into two groups according to the teaching model: Model 1 (N = 1181; 1999-2003) and Model 2 (N = 2085; 2003-2007). Model 2 increased practical skill activities to 75% of the total versus 60% in Model 1. Furthermore, the teaching material provided to the students before the course was more objective than that used for Model 1. Scores greater than 85% in the theoretical evaluation and approval in the evaluation of practice by the instructor were considered to be a positive outcome. Multiple logistic regression was used to adjust for potential confounders (specialty, residency, study time, opportunity to enhance practical skills during the course and location where the course was given). Compared to Model 1, Model 2 presented odds ratios (OR) indicating better performance in the theoretical (OR = 1.34; 95%CI = 1.10-1.64), practical (OR = 1.19; 95%CI = 0.90-1.57), and combined (OR = 1.38; 95%CI = 1.13-1.68) outcomes. Increasing the time devoted to practical skills did not improve the performance of ACLS students. PMID:21085890

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

2010-11-19

386

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

387

Predicting defibrillation success by ‘genetic’ programming in patients with out-of-hospital cardiac arrest  

Microsoft Academic Search

Background: In some patients with ventricular fibrillation (VF) there may be a better chance of successful defibrillation after a period of chest compression and ventilation before the defibrillation attempt. It is therefore important to know whether a defibrillation attempt will be successful. The predictive power of a model developed by ‘genetic’ programming (GP) to predict defibrillation success was studied. Methods

M. Podbregar; M. Kova?i?; A. Podbregar-Marš; M. Brezocnik

2003-01-01

388

Absence epilepsy and sinus dysrhythmia in mice lacking the pacemaker channel HCN2.  

PubMed

Hyperpolarization-activated cation (HCN) channels are believed to be involved in the generation of cardiac pacemaker depolarizations as well as in the control of neuronal excitability and plasticity. The contributions of the four individual HCN channel isoforms (HCN1-4) to these diverse functions are not known. Here we show that HCN2-deficient mice exhibit spontaneous absence seizures. The thalamocortical relay neurons of these mice displayed a near complete loss of the HCN current, resulting in a pronounced hyperpolarizing shift of the resting membrane potential, an altered response to depolarizing inputs and an increased susceptibility for oscillations. HCN2-null mice also displayed cardiac sinus dysrhythmia, a reduction of the sinoatrial HCN current and a shift of the maximum diastolic potential to hyperpolarized values. Mice with cardiomyocyte- specific deletion of HCN2 displayed the same dysrhythmia as mice lacking HCN2 globally, indicating that the dysrhythmia is indeed caused by sinoatrial dysfunction. Our results define the physiological role of the HCN2 subunit as a major determinant of membrane resting potential that is required for regular cardiac and neuronal rhythmicity. PMID:12514127

Ludwig, Andreas; Budde, Thomas; Stieber, Juliane; Moosmang, Sven; Wahl, Christian; Holthoff, Knut; Langebartels, Anke; Wotjak, Carsten; Munsch, Thomas; Zong, Xiangang; Feil, Susanne; Feil, Robert; Lancel, Marike; Chien, Kenneth R; Konnerth, Arthur; Pape, Hans-Christian; Biel, Martin; Hofmann, Franz

2003-01-15

389

Permanent cardiac pacing for neurocardiogenic syncope  

PubMed Central

Vasovagal syncope is not a benign condition in the elderly population. In patients not responsive to conservative therapy and whose abrupt faints are associated with serious injuries and seriously affected quality of life, pacemaker therapy was suggested. However, the usefulness of cardiac pacing for the prevention of recurrences of vasovagal syncope remains controversial because of the dominant role of the vasodepressor component during the episode. In the Medical Center Alkmaar, the Head-Up Tilt Test (HUTT) has been used since 1996 during the work-up of patients who present with vasovagal syncope. The HUTT showed a dominant cardioinhibitory response in 4.5% of our patients; in elderly patients with vasovagal syncope without prodromal symptoms and refractory on conservative therapy, pacemaker therapy was very effective in preventing syncope during long-term follow-up. (Neth Heart J 2008;16(Suppl1):S15-S19.)

Ruiter, J.H.; Barrett, M.

2008-01-01

390

Mitral valve closure and left ventricular filling time in patients with VDD pacemakers. Assessment of the onset of left ventricular systole and the end of diastole  

Microsoft Academic Search

The effect of mitral valve closure on left ventricular filling time and its relation to the onset of systole were assessed from mitral valve echocardiograms and simultaneous apex cardiograms in 21 normal subjects, 11 patients with left bundle branch block, and 19 patients with VDD pacemakers programmed for atrioventricular intervals of 50, 150, and 250 ms. The interval between the

H von Bibra; A Wirtzfeld; R Hall; K Ulm; H Blömer

1986-01-01

391

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

392

Exercise Trajectories of Women from Entry to a 6-Month Cardiac Rehabilitation Program to One Year after Discharge  

PubMed Central

Background. Physical activity is associated with reduced mortality and morbidity. Cardiac rehabilitation (CR) is an effective intervention for patients with cardiovascular disease (CVD). Unfortunately, women are less likely to engage in, or sustain, regular physical activity. Objectives were to (1) describe women's guidelines-based levels of physical activity during and after CR and (2) determine the physical activity trajectories of women from entry to CR to one year after CR. Methods and Results. A prospective, longitudinal study of 203 women with CVD enrolled in a 6-month CR program. Physical activity was measured using the Godin Leisure Time Exercise Questionnaire (LSI), focusing on moderate-strenuous activity. Data were analyzed using latent class growth analysis (LCGA) and logistic regression. Mean scores on the LSI showed women to be “active” at all follow-up points. LCGA revealed a two-class model, respectively, called “inactive relapsers” and “moderately active relapsers.” Predictors of the “moderately active relapsers” class were employment status and diagnosis of myocardial infarction. Conclusions. Women achieved the recommended physical activity levels by the end of CR and sustained them until one year after CR. LCGA allowed us to determine the class trajectories associated with moderate-strenuous activity and, from these, to identify implications for targeted intervention.

Arthur, Heather M.; Blanchard, Chris; Gunn, Elizabeth; Kodis, Jennifer; Walker, Steven; Toner, Brenda

2013-01-01

393

Radioisotope thermoelectric generators for implanted pacemakers  

SciTech Connect

This paper discusses the development and application of long-life lithium batteries and the problems associated with miniature radioisotope thermoelectric generators (RITEG) with service lives of 10 years or longer. On eof the main problems encountered when devising a radioisotope heat source (RHS) for an RITEG is to obtain biomedical /sup 238/PuO/sub 2/ with a specific neutron yield of 3.10/sup 3/-4.10/sup 3/ (g /SUP ./ sec)/sup -1/, equivalent to metallic Pu 238, and with a content of gamma impurities sufficient to ensure a permissible exposure a permissible exposure does rate (EDR) of a mixture of neutron and gamma radiation. After carrying out the isotope exchange and purifying the initial sample of its gamma impurity elements, the authors obtain biomedical Pu 238 satisfying the indicated requirements king suitable for use in the power packs of medical devices. Taking the indicated specifications into account, the Ritm-1o and gamma radioisotope heat sources were designed, built, tested in models and under natural conditions, and then into production as radioisotope thermoelectric generators designed to power the electronic circuits of implanted pacemakers. The Ritm-MT and Gemma radioisotope thermoelectric generators described are basic units, which can be used as self-contained power supplies for electronic equipment with power requirements in the micromilliwatt range.

Pustovalov, A.A.; Bovin, A.V.; Fedorets, V.I.; Shapovalov, V.P.

1986-08-01

394

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

PubMed Central

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

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

2010-01-01

395

Same-day transfer of patients to the cardiac telemetry unit after surgery: the Rapid after Bypass Back into Telemetry (RABBIT) program.  

PubMed

Early data from this project suggest that the RABBIT program fulfilled the process improvement goals of decreasing costs of cardiac surgery and maintaining high quality. Decreased cost was achieved by decreasing time to extubation and decreasing length of stay in the ICU and the total length of stay in the hospital. The cost savings were achieved without compromising the quality of care, which was assessed by measuring rates of readmission to the ICU and to the hospital and by surveying patients about their level of satisfaction. The success of the RABBIT program can be attributed to several factors. First, members of the cardiac surgery quality improvement team worked well together to solve problems and overcome obstacles, particularly after the pilot program. Second, naming the program helped to motivate staff, physicians, and patients. Outcome data was shared with the staff quarterly, and successes were celebrated. Finally, the use of a facilitator early in the process to establish the process with the surgeons and the staff was invaluable. Opportunities for continued improvement include resolving operational difficulties related to availability of beds and staffing, continuing work with physicians in changing practice patterns, increasing efficiency in scheduling operating rooms, and adjusting the preoperative education provided to patients and their families about the length of stay to expect. Quarterly outcome analysis continues, with reports to the cardiac surgery quality improvement team. The team continues to explore creative solutions to the aforementioned issues, as the goal of having 25% of patients who undergo cardiac surgery be transferred to the CTU on the day of surgery has remained elusive. PMID:11873752

Sakallaris, B R; Halpin, L S; Knapp, M; Sheridan, M J

2000-04-01

396

Group-mediated activity counseling and traditional exercise therapy programs: Effects on health-related quality of life among older adults in cardiac rehabilitation  

Microsoft Academic Search

Background: Regular physical activity has been consistently related to improvements in health- related quality of life (HRQL) in older\\u000a adults. Nevertheless, systematic investigations of the influence of exercise therapy on older men and women enrolled in cardiac\\u000a rehabilitation remain sparse.Purpose: The primary purpose of this investigation was to compare the effects of a group-mediated cognitive behavioral physical activity\\u000a intervention program

Brian C. Focht; Lawrence R. Brawley; W. Jack Rejeski; Walter T. Ambrosius

2004-01-01

397

Entrainment of coupled oscillators on regular networks by pacemakers  

NASA Astrophysics Data System (ADS)

We study Kuramoto oscillators, driven by one pacemaker, on d -dimensional regular topologies with nearest neighbor interactions. We derive the analytical expressions for the common frequency in the case of phase-locked motion and for the critical frequency of the pacemaker, placed at an arbitrary position in the lattice, so that above the critical frequency no phase-locked motion is possible. We show that the mere change in topology from an open chain to a ring induces synchronization for a certain range of pacemaker frequencies and couplings, while keeping the other parameters fixed. Moreover, we demonstrate numerically that the critical frequency of the pacemaker decreases as a power of the linear size of the lattice with an exponent equal to the dimension of the system. This leads in particular to the conclusion that for infinite-dimensional topologies the critical frequency for having entrainment decreases exponentially with increasing size of the system, or, more generally, with increasing depth of the network, that is, the average distance of the oscillators from the pacemaker.

Radicchi, Filippo; Meyer-Ortmanns, Hildegard

2006-03-01

398

Cardiac pacing.  

PubMed

The basic electrophysiology of temporary and permanent cardiac pacing is reviewed, as are the indications, the types of pacing systems, and the methods of implantation. Recent developments in power sources and leads are described. The mercury-zinc battery is now obsolete and is being replaced by lithium, rechargeable, and isotopic power systems. While ventricular pacing continues to be the standard, a brief review of atrial programmed systems is given, including atrial pacing and atrioventricular synchronized and atrioventricular sequential pacing. Conventional pacing is aimed at the control of symptomatic bradycardia. Brief reference is made to experimental pacing systems designed to control ventricular or supraventricular tachyarrhythmias. PMID:453992

Smyth, N P

1979-03-01

399

Improving outcomes in high-risk populations using REACH: an inpatient cardiac risk reduction program.  

PubMed

The high prevalence of cardiovascular disease and its associated mortality rates mandate that risk reduction strategies be addressed in high-risk populations, including those diagnosed with atherosclerotic vascular disease, heart failure, and diabetes mellitus. Hospital-based systems that can identify and guide management of these high-risk populations can be effective adjuncts to patient care.In 2001, an inpatient cardiovascular risk assessment program called REACH was developed at Advocate Lutheran General Hospital (ALGH), a community teaching hospital in Illinois. REACH uses an intranet-based data repository capable of prospectively identifying high-risk patients by displaying an alert on the inpatient computerized medical record. Management and education protocols are accessed through various links. An assessment and treatment plan is incorporated into the discharge instructions and sent to the primary care physician.A total of 9035 patients at ALGH were included in the analysis (n = 2807 at baseline and n = 6007 at year 6). Adherence to pharmacological therapy and monitoring of lipid profile improved in all 5 of the inpatient populations. Statistically significant improvement was noted in all outcomes in the cardiovascular and stroke populations (P < 0.05). In populations with diabetes and heart failure, all but one showed a statistically significant improvement. In the peripheral vascular disease population, 2 of the 5 showed statistically significant improvement. Adherence to outcome criteria in all high-risk populations over the 6-year time frame resulted in a 119% change in guideline compliance.The REACH program successfully uses patient information systems to provide a quality improvement tool that promotes optimal patient management of high-risk vascular disease states. PMID:19726930

Patel, Parag V; Gilski, Donna; Morrison, Jeanette

2009-09-01

400

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

2012-08-23

401

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

402

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

403

Uni and Bipolar Pacing Threshold Measurements with Capturecontrol, a New Automatic Pacemaker Function for Capture Verification  

Microsoft Academic Search

It is mandatory in pacemaker patients to determine the pacing threshold at each follow-up visit. To facilitate the pacing threshold measurements, complete automatic pacemaker tests are being developed. A new pacemaker algorithm for automatic capture verification (Capturecontrol) detects the presence of the evoked response signal 70–100 ms after the pacing pulse. The aim of this study was to determine the

Andreas Schuchert; Thomas Meinertz

1999-01-01

404

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

Microsoft Academic Search

During the initial testing of Radio Leicester a swept-frequency technique for testing radio antennae was shown to affect demand pacemakers by inhibition of the pacing impulse and to interfere with physiological monitoring equipment. Adequate filtering of demand pacemakers is necessary to eliminate this interference. There is no evidence that such testing has any effect on the function of fixed-rate pacemakers.

Bryan A. Pickers; M. J. Goldberg

1969-01-01

405

Contemporary Developments in the Pacemaker World  

Microsoft Academic Search

ICU leaders need to be current with recent technological advances related to cardiac implantable electrical devices (CIEDs). This update will review the following 4 topics: (1) an update on contemporary technology for CIED companies headquartered in the United States, (2) unique features of one CIED company headquartered in Europe, (3) ICU considerations for patients with CIEDs for whom do not

William A. Shapiro; Charles L. Witherell

2011-01-01

406

The Apparent and the Effective PR Interval, Insights for Cardiac Pacing  

PubMed Central

A 75-year-old-male patient with dual chamber pacemaker presented with a bizarre EKG showing a unique spike within the QRS complex. Apparent PR interval was 160 ms and effective atrio-right ventricular delay was 210 ms due to right bundle branch block. Sensed AV delay was set at 180 ms causing pseudofusions. Insights regarding cardiac pacing are presented.

Kossaify, Antoine

2011-01-01

407

NEUROHORMONAL MODULATION OF THE LIMULUS HEART: AMINE ACTIONS ON CARDIAC GANGLION NEURONES  

Microsoft Academic Search

SUMMARY Octopamine (OCT), dopamine (DA), epinephrine (EPI) and norepine- phrine (NE) are endogenous excitors of the Limulus heart. The cellular sites of action of these amines were investigated by recording responses of neurones in the cardiac ganglion. There was an increase in spike fre- quency in pacemaker neurones, accompanied by a depolarization and an increase in the rate of repolarization

GEORGE J. AUGUSTINE; RAYMOND H. FETTERER

408

Cardiac-Resynchronization Therapy with or without an Implantable Defibrillator in Advanced Chronic Heart Failure  

Microsoft Academic Search

background We tested the hypothesis that prophylactic cardiac-resynchronization therapy in the form of biventricular stimulation with a pacemaker with or without a defibrillator would reduce the risk of death and hospitalization among patients with advanced chronic heart failure and intraventricular conduction delays. methods A total of 1520 patients who had advanced heart failure (New York Heart Association class III or

Michael R. Bristow; Leslie A. Saxon; John Boehmer; Steven Krueger; David A. Kass; Teresa De Marco; Peter Carson; Lorenzo DiCarlo; David DeMets; Bill G. White; Dale W. DeVries; Arthur M. Feldman

2010-01-01

409

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

410

Magnetic Resonance Imaging in patients with ICDs and Pacemakers  

PubMed Central

Magnetic resonance (MR) imaging has unparalleled soft-tissue imaging capabilities. The presence of devices such as pacemakers and implantable cardioverter/defibrillators (ICDs), however, is historically considered a contraindication to MR imaging. These devices are now smaller, with less magnetic material and improved electromagnetic interference protection. This review summarizes the potential hazards of the device-MR environment interaction, and presents updated information regarding in-vivo and in-vitro experiments. Recent reports on patients with implantable pacemakers and ICDs who underwent MR scan shows that under certain conditions patients with these implanted systems may benefit from this imaging modality. The data presented suggests that certain modern pacemaker and ICD systems may indeed be MR safe. This may have major clinical implications on current imaging practice.

Nair, Prashant; Roguin, Ariel

2005-01-01

411

Electroacupuncture on a patient with pacemaker: a case report.  

PubMed

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

Vasilakos, Dimitrios G; Fyntanidou, Barbara P

2011-03-08

412

Electronic cardiac medicine: present and future opportunities.  

PubMed

The second half of the 20th century witnessed a revolution in electronic medicine similar to that in pharmacology in the decades before. The advent of the implantable pacemaker, implantable cardioverter-defibrillators, cardiac resynchronisation therapies, insertable loop recorders and more, have improved diagnoses and reduced mortality and morbidity in millions of patients suffering from cardiac disease. The possibility to monitor patients continually without need for frequent office visits has the potential to reduce follow-up burden on physicians, facilitate increased use of home-based care and further improve the safety for patients. This review summarises the role of cardiac device therapies today and some of the developments which we can hope for in the nearest future. PMID:20809436

Auricchio, A; Moccetti, T

2010-09-01

413

A rare cause of pacemaker failure: interatrial block.  

PubMed

Pacemaker and implantable cardioverter defibrillators (ICD) systems are useful in detection and differentiation of many symptomatic and asymptomatic arrhythmias. In this report, we described a rare condition that caused by failure in detection of a clinical tachyarrhythmia by a dual chamber pacemaker that implanted because of intermittent atrioventricular (AV) block and sinus node disease in a 46-year-old patient. In our case, bidirectional interatrial block was demonstrated; and the symptoms associated with high ventricular rate caused by left atrial tachyarrhythmias relieved after AV node ablation. PMID:24047493

Demircan, Sabri; Yuksel, Serkan; Gulel, Okan

2013-01-20

414

[Development and research of temporary demand pacemaker with electrocardiosignal display].  

PubMed

A temporary demand pacemaker with electrocardiosignal display is introduced in this paper. Double way low-noise electrocardiosignal preamplifier, amplitude limiter, high and low pass filter, 50 Hz notch filter, TTL level generator and stimulating pulse formation circuit are components of the hardware electrocircuit. The demand pacing and the electrocardiosignal display are separately controlled by the software in which the double microcontrollers communications technique is used. In this study, liquid crystal display is firstly used in body surface electrocardiosignal display or intracardial electrophysiologic signal display when the temporary demand pacemaker is installed and put into use. The machine has proven clinically useful and can be of wide appliation. PMID:15357453

Fan, Shounian; Jiang, Chenxi; Cai, Yunchang; Pan, Yangzhong; Yang, Tianhe; Wu, Qiang; Zheng, Yaxi; Liu, Xiaoqiao; Li, Shiying

2004-08-01

415

Cerebral arrhythmia influencing cardiac rhythm: a case of ictal bradycardia.  

PubMed

Partial seizures of temporal origin can be associated with clinically significant tachycardia or bradycardia. Ictal bradycardia and asystole has been implicated in the etiology of sudden unexpected death in epileptic patients (SUDEP). Although symptomatic ictal bradycardia has been relatively well described in the literature; information on asymptomatic ictal bradycardia is scarce. We report a case of asymptomatic ictal bradycardia diagnosed during video EEG telemetry that was subsequently implanted with a cardiac pacemaker. PMID:16798021

Almansori, Mohammed; Ijaz, Mohammed; Ahmed, S Nizam

2006-06-23

416

Cardiac pacing in patients with a cervical spinal cord injury  

Microsoft Academic Search

Study design:Retrospective medical record review.Objectives:To compare patients, admitted to an intensive care unit (ICU) with an acute cervical spinal cord injury (SCI) and documented motor deficit, who did, with those who did not, require a cardiac pacemaker.Setting:South Australian Tertiary Referral Intensive Care and Spinal Injury Unit.Methods:Retrospective medical record review and data set linkage.Results:From 1995 to 2007, 465 patients sustained a

P Rangappa; J Jeyadoss; A Flabouris; J M Clark; R Marshall

2010-01-01

417

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

418

Evaluation of pacemaker pulse generator and patient longevity in patients aged 1 day to 20 years.  

PubMed

The longevity of pediatric patients requiring pacemakers and the survival rates of the implanted generators were evaluated. From January 1970 to December 1985, 96 patients aged 1 day to 20 years underwent 162 pulse generator implantation procedures. Indication for initial implantation was surgically induced heart block in 52 patients, sick sinus syndrome in 20, congenital complete heart block with symptoms of low cardiac output in 19 and tachydysrhythmia control in 5. Modal age at initial implantation was less than 1 year; median age was 5 years. During this period 90 generators were removed from service: 49 (54%) because of generator failure, 22 (24%) because the patient died, 12 (13%) because of elective upgrade at the time of lead failure or cardiac surgery, 5 (6%) because of generator pocket infection and 2 (2%) because of manufacturer's recall. Pulse generators were separated into 4 groups based upon generator technology. Group I (n = 16) were asynchronous units with mercury-zinc batteries; group II (n = 18) were single-chamber demand units with mercury-zinc batteries; group III (n = 14) were single-chamber demand units with rechargeable batteries; and group IV (n = 114) were single- or dual-chamber demand units with lithium batteries. Patient survival rate was 84% at 6 months and 70% by 109 months. There was no further decrease to the end of the study period. Six-month generator survival rate was 82% for all groups, mostly a reflection of patient deaths.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3825943

Serwer, G A; Mericle, J M

1987-04-01

419

K+ Channel Regulator KCR1 Suppresses Heart Rhythm by Modulating the Pacemaker Current If  

PubMed Central

Hyperpolarization-activated, cyclic nucleotide sensitive (HCN) channels underlie the pacemaker current If, which plays an essential role in spontaneous cardiac activity. HCN channel subunits (HCN1-4) are believed to be modulated by additional regulatory proteins, which still have to be identified. Using biochemistry, molecularbiology and electrophysiology methods we demonstrate a protein-protein interaction between HCN2 and the K+ channel regulator protein 1, named KCR1. In coimmunoprecipitation experiments we show that KCR1 and HCN2 proteins are able to associate. Heterologously expressed HCN2 whole-cell current density was significantly decreased by KCR1. KCR1 profoundly suppressed IHCN2 single-channel activity, indicating a functional interaction between KCR1 and the HCN2 channel subunit. Endogenous KCR1 expression could be detected in adult and neonatal rat ventriculocytes. Adenoviral-mediated overexpression of KCR1 in rat cardiomyocytes (i) reduced If whole-cell currents, (ii) suppressed most single-channel gating parameters, (iii) altered the activation kinetics, (iv) suppressed spontaneous action potential activity, and (v) the beating rate. More importantly, siRNA-based knock-down of endogenous KCR1 increased the native If current size and single-channel activity and accelerated spontaneous beating rate, supporting an inhibitory action of endogenous KCR1 on native If. Our observations demonstrate for the first time that KCR1 modulates IHCN2/If channel gating and indicate that KCR1 serves as a regulator of cardiac automaticity.

Michels, Guido; Er, Fikret; Khan, Ismail F.; Endres-Becker, Jeannette; Brandt, Mathias C.; Gassanov, Natig; Johns, David C.; Hoppe, Uta C.

2008-01-01

420

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

PubMed

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

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

2011-12-03

421

Overdrive Ventricular Pacing in Pacemaker Recipients with Permanent Atrial Fibrillation and Sleep Apnea  

PubMed Central

Study Objectives: Cardiac pacing is ineffective in obstructive sleep apnea (SA), but it can alleviate central SA/Cheyne-Stokes respiration (CSA) in patients with heart failure (HF). We examined whether overnight overdrive ventricular pacing (OVP) has an effect on SA in pacemaker recipients with permanent atrial fibrillation (AF). Methods: An apnea-hypopnea index (AHI) ? 15 was confirmed in 28/38 patients screened by finger pulse oximetry during overnight ventricular pacing at a backup rate of 40 bpm (BUV40). These patients (23 men, 77.9 ± 7.6 y, BMI 27.6 ± 5.1 kg/m2) were randomly assigned to 2 consecutive nocturnal ventilation polygraphies with BUV40 versus OVP at 20 bpm above the mean nocturnal heart rate observed during screening. Results: During BUV40 versus OVP, (1) mean heart rate was 49 ± 8 versus 71 ± 8 bpm (p < 0.0001) and percent ventricular pacing 36% ± 38% versus 96% ± 6% (p < 0.0001); (2) AHI was 35.4 ± 11.9 versus 32.5 ± 15.5 (p = ns), central AHI 23.9 ± 11.8 versus 19.1 ± 12.7 (p < 0.001), and obstructive AHI 11.6 ± 13.1 versus 13.5 ± 15.9 (p = ns). In 15/28 patients without HF, mean left ventricular ejection fraction (LVEF) was 51% ± 17%, AHI was 37.6 ± 11.0 during BUV40 and 39.0 ± 11.5 during OVP, versus 32.8 ± 12.9 and 24.9 ± 16.5 in 13/28 patients with HF (p = 0.02) and mean LVEF 35% ± 15% (p = 0.01). Between the 2 subgroups, (1) central AHI was 23.6 ± 12.4 during BUV40 and 21.5 ± 14.0 during OVP versus 24.1 ± 11.6 and 16.2 ± 10.7 (p = 0.05); (2) obstructive AHI was 14.0 ± 13.7 during BUV40 and 17.6 ± 16.5 during OVP versus 8.8 ± 12.3 and 8.7 ± 14.3 (p = ns). Conclusions: The prevalence of SA, predominantly central, was high in our pacemaker recipients with permanent AF. In those with HF, a single overnight OVP resulted in modest improvement in central events. Citation: Bordier P; Maurice-Tison S; Ramana NK. Overdrive ventricular pacing in pacemaker recipients with permanent atrial fibrillation and sleep apnea. J Clin Sleep Med 2012;8(3):257-264.

Bordier, Philippe; Maurice-Tison, Sylvie; Ramana, Nishi Krishna

2012-01-01

422

Experiences of Program Directors in the Enrollment of Patients who had Percutaneous Transluminal Coronary Angioplasty without Myocardial Infarction into Phase 2 Cardiac Rehabilitation Programs.  

National Technical Information Service (NTIS)

The benefits of cardiac rehabilitation (CR) have been demonstrated repeatedly. Little is known about the benefits percutaneous transluminal coronary angioplasty (PTCA) patients without myocardial infarction (MT) achieve due to their limited enrollment in ...

M. A. Koch

1996-01-01

423

His bundle electrograms in 51 patients requiring permanent transvenous pacemakers.  

PubMed

Fifty-one patients required the implantation of a Cordis Omnis-Stanicor permanent pacemaker. His bundle electrograms studies, which included right atrial pacing and sinoatrial (SA) node postsuppression recovery times, were performed prior to the implantations. Pacing and sensing thresholds were obtained in all patients. Syncope or episodes of dizziness were the presenting symptoms in virtually every patient. Twenty-eight of the 51 patients had the sick sinus syndrome. Only nine patients were in complete heart block, and an additional nine were in second-degree heart block. The His bundle electrogram technique was not particularly helpful in selecting the potential pacemaker candidate. The symptomatic patient with second- or third-degree heart block requires a pacemaker. In the sick sinus syndrome, the His bundle electrogram was a disappointing tool in detecting abnormalities. In chronic bundle branch block, the His bundle electrogram appears to play a major role. A prolonged H-V interval in a symptomatic patient, in whom a specific noncardiac cause cannot be identified, signifies that a pacemaker is required. PMID:875439

Gould, L; Reddy, C V; Brevetti, G C; Cifarelli, F; Maghazeh, P; Shin, C S

1977-07-01

424

Right giant atrial thrombosis and pulmonary embolism complicating pacemaker leads.  

PubMed

We describe a case of a patient with bilateral pulmonary embolism because of a giant intracardiac thrombus anchored on a right atrial pacemaker lead treated with unfractionated heparin and the consecutively complete thrombus resolution after 5-6 days. PMID:23997072

D'Aloia, Antonio; Bonadei, Ivano; Vizzardi, Enrico; Curnis, Antonio

2013-08-30

425

Pacemaker synaptic interactions: Modelled locking and paradoxical features  

Microsoft Academic Search

This communication describes a model for two “pacemaker” (i.e., regularly firing) nerve cells, such that one elicits IPSP's in the other. The assumptions involve essentially a linear dependence (“delay function”) of the postsynaptic interval lengthening (or “delay”) produced by the IPSP's on the position (or “phase”) with respect to the preceding spike of the latter's arrival. When the number of

J. P. Segundo

1979-01-01

426

Pacemaker lead infection: echocardiographic features, management, and outcome  

PubMed Central

Objective—To compare transthoracic and transoesophageal echocardiography (TTE, TOE) in patients with permanent pacemaker lead infection and to evaluate the safety of medical extraction in cases of large vegetations.?Methods—TTE and TOE were performed in 23 patients with definite pacemaker lead infection. Seventeen patients without previous infection served as a TOE reference for non-infected leads.?Results—TTE was positive in seven cases (30%) whereas with TOE three different types of vegetations attached to the leads were visualised in 21 of the 23 cases (91%). Of the 20 patients with vegetations and lead culture, 17 (85%) had bacteriologically active infection. Left sided valvar endocarditis was diagnosed in two patients. In the control group, strands were visualised by TOE in five patients, and vegetations in none. Medical extraction of vegetations ? 10 mm was performed in 12 patients and was successful in nine (75%) without clinical pulmonary embolism. After 31.2 (19.1) months of follow up (mean (SD)), all patients except one were cured of infection; three died from other causes.?Conclusions—Combined with bacteriological data, vegetations seen on TOE strongly suggest pacemaker lead infection. Normal TTE examinations do not exclude this diagnosis because of its poor sensitivity. Medical extraction of even large vegetations appeared to be safe.?? Keywords: pacemaker lead infection;  transoesophageal echocardiography

Victor, F; De Place, C; Camus, C; Le Breton, H; Leclercq, C; Pavin, D; Mabo, P; Daubert, C

1999-01-01

427

Venous Thrombosis and Stenosis After Implantation of Pacemakers and Defibrillators  

Microsoft Academic Search

Venous complications of pacemaker\\/ implantable cardioverter defibrillator (ICD) system implantation rarely cause immediate clinical problems. The challenge starts when patients come for system revision or upgrade. Numerous reports of venous complications such as stenosis, occlusions, and superior vena cava syndrome have been published. We reviewed current knowledge of these complications, management, and their impact on upgrade\\/revision procedures. One study has

Grzegorz Rozmus; James P. Daubert; David T. Huang; Spencer Rosero; Burr Hall; Charles Francis

2005-01-01

428

Inadvertent lumbosacral plexopathy due to temporary pacemaker implantation.  

PubMed Central

Reported here is a 70-year-old man who suffered from a lumbosacral plexopathy after a temporary pacemaker implantation. Drawing attention to the increased number of femoral catheterizations in cardiovascular practice, we have highlighted some neuromuscular complications pertaining to these type of interventions.

Ozcan, Firat; Guray, Yesim; Ozcakar, Levent; Korkmaz, Sule

2006-01-01

429

Secure pacemaker fixation critical for prevention of Twiddler's syndrome  

Microsoft Academic Search

A two year old, female spayed border collie presented three weeks after permanent pacemaker implantation for weakness, lethargy and collapse. Electrocardiogram documented complete (3rd degree) atrioventricular (AV) block, the absence of pacing and a ventricular escape rhythm. Thoracic radiographs revealed retraction and dislodgement of the passive fixation lead from the right ventricular apex. During a procedure to reposition the lead,

Sarah A Zimmerman; Janice M Bright

2004-01-01

430

Biomechanics of early cardiac development.  

PubMed

Biomechanics affect early cardiac development, from looping to the development of chambers and valves. Hemodynamic forces are essential for proper cardiac development, and their disruption leads to congenital heart defects. A wealth of information already exists on early cardiac adaptations to hemodynamic loading, and new technologies, including high-resolution imaging modalities and computational modeling, are enabling a more thorough understanding of relationships between hemodynamics and cardiac development. Imaging and modeling approaches, used in combination with biological data on cell behavior and adaptation, are paving the road for new discoveries on links between biomechanics and biology and their effect on cardiac development and fetal programming. PMID:22760547

Goenezen, Sevan; Rennie, Monique Y; Rugonyi, Sandra

2012-07-04

431

A stroke of bad luck: left ventricular pacemaker malposition.  

PubMed

Lead wire malposition is thought to be a rare complication of both permanent and temporary pacemaker implantation. The actual incidence and prevalence are unknown because of lack of reporting, which complicates consistency in treatment. Potential safeguards to prevent complications as a result of lead malposition are readily available, effective, and inexpensive, but underused. An 80-year-old white man presented to our institution with right-arm paresthesias and weakness, as well as facial numbness, 4 months after undergoing single-chamber pacemaker placement by an outside hospital because of tachybrady syndrome. Computed tomography scan of the head revealed a recent ischemic stroke. Electrocardiography revealed right bundle-branch block morphology of paced beats. Chest radiography raised the suspicion of lead malposition because of the posterior deflection of the lead wire on the lateral view. Transesophageal echocardiography conclusively demonstrated a pacemaker lead wire that transversed the aortic valve into the left ventricle without the presence of thrombus. The patient underwent successful removal of the device with a transcatheter approach, and a replacement pacemaker was placed for symptomatic bradycardia. It was recently suggested that echocardiography is not able to adequately detect thrombi on lead wires and that all patients with stroke should undergo open heart surgery for device extraction. We think that this does not adequately incorporate the significant comorbidities for some patients in the risk-benefit decision-making processes and that a transcutaneous approach is reasonable for patients without evidence of thrombi who are poor surgical candidates for an open heart procedure. A 12-lead electrocardiogram should be performed on every patient after pacemaker insertion. If right bundle-branch block morphology of paced beats is noted, chest radiography including a lateral view should be ordered. If there is any ambiguity regarding lead placement, echocardiography should be performed for determining lead malposition. PMID:17600676

Reising, Scott; Safford, Robert; Castello, Ramon; Bosworth, Veronica; Freeman, William; Kusumoto, Fred

2007-06-27

432

Dynamic MicroRNA Expression Programs During Cardiac Differentiation of Human Embryonic Stem Cells: Role for miR-499  

PubMed Central

Background MicroRNAs (miRNAs) are a newly discovered endogenous class of small noncoding RNAs that play important posttranscriptional regulatory roles by targeting messenger RNAs (mRNAs) for cleavage or translational repression. Human embryonic stem cells (hESCs) are known to express miRNAs that are often undetectable in adult organs, and a growing body of evidence has implicated miRNAs as important arbiters of heart development and disease. Methods and Results To better understand the transition between the human embryonic and cardiac “miRNA-omes”, we report here the first miRNA profiling study of cardiomyocytes derived from hESCs (hESC-CMs). Analyzing 711 unique miRNAs, we then identify several interesting miRNAs, including miR-1, miR-133, and miR-208, that have been previously reported to be involved in cardiac development and disease and that show surprising patterns of expression across our samples. We also identify novel miRNAs such as miR-499 that are strongly associated with cardiac differentiation, and which shares many predicted targets with miR-208. Over-expression of miR-499 and miR-1 resulted in upregulation of important cardiac myosin heavy chain genes in embryoid bodies; miR-499 over-expression also caused upregulation of the cardiac transcription factor MEF2C. Conclusions Taken together, our data give significant insight into the regulatory networks that govern hESC differentiation, and highlights the ability of miRNAs to perturb, and even control, the genes that are involved in cardiac specification of hESCs.

Wilson, Kitchener D.; Hu, Shijun; Venkatasubrahmanyam, Shivkumar; Fu, Ji-Dong; Sun, Ning; Abilez, Oscar J.; Baugh, Joshua J. A.; Jia, Fangjun; Ghosh, Zhumur; Li, Ronald A.; Butte, Atul J.; Wu, Joseph C.

2011-01-01

433

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

PubMed

Patients with perturbed metabolic control are more prone to develop cardiac rhythm disturbances. The main purpose of the present preclinical study was to investigate the possible role of euglycemic hyperinsulinemia in development of cardiac arrhythmias. Euglycemic hyperinsulinemia was induced in conscious rabbits equipped with a right ventricular pacemaker electrode catheter by hyperinsulinemic euglycemic glucose clamp (HEGC) applying two different rates of insulin infusion (5 and 10 mIU/kg/min) and variable rate of glucose infusion to maintain euglycemia (5.5?±?0.5 mmol/l). The effect of hyperinsulinemia on cardiac electrophysiological parameters was continuously monitored by means of 12-lead surface ECG recording. Arrhythmia incidence was determined by means of programmed electrical stimulation (PES). The possible role of adrenergic activation was investigated by determination of plasma catecholamine levels and intravenous administration of a beta adrenergic blocking agent, metoprolol. All of the measurements were performed during the steady-state period of HEGC and subsequent to metoprolol administration. Both 5 and 10 mIU/kg/min insulin infusion prolonged significantly QTend, QTc, and Tpeak-Tend intervals. The incidence of ventricular arrhythmias generated by PES was increased significantly by euglycemic hyperinsulinemia and exhibited linear relationship to plasma levels of insulin. No alteration on plasma catecholamine levels could be observed; however, metoprolol treatment restored the prolonged QTend, QTc, and Tpeak-Tend intervals and significantly reduced the hyperinsulinemia-induced increase of arrhythmia incidence. Euglycemic hyperinsulinemia can exert proarrhythmic effect presumably due to the enhancement of transmural dispersion of repolarization. Metoprolol treatment may be of benefit in hyperinsulinemia associated with increased incidence of cardiac arrhythmias. PMID:23474828

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

2013-03-10

434

Cardiac amyloidosis  

MedlinePLUS

... Primary cardiac amyloidosis - AL type; Secondary cardiac amyloidosis - AA type; Stiff heart syndrome; Senile amyloidosis ... arrhythmias and conduction disturbances (heart block). Secondary amyloidosis (AA type) rarely affects the heart. However, a form ...

435

Bifurcations in a nonlinear model of the baroreceptor-cardiac reflex  

NASA Astrophysics Data System (ADS)

We investigate the dynamic properties of a nonlinear model of the human cardio-baroreceptor control loop. As a new feature we use a phase effectiveness curve to describe the experimentally well-known phase dependency of the cardiac pacemaker's sensitivity to neuralactivity. We show that an increase of sympathetic time delays leads via a Hopf bifurcation to sustained heart rate oscillations. For increasing baroreflex sensitivity or for repetitive vagal stimulation we observe period-doubling, toroidal oscillations, chaos, and entrainment between the rhythms of the heart and the control loop. The bifurcations depend crucially on the involvement of the cardiac pacemaker's phase dependency. We compare the model output with experimental data from electrically stimulated anesthetized dogs and discuss possible implications for cardiac arrhythmias.

Seidel, H.; Herzel, H.

1998-04-01

436

Evaluation of a rechargeable pacemaker system.  

PubMed

A rechargeable-demand nickel-cadmium pulse generator for permanent transvenous cardiac pacing was evaluated in 66 patients. During a cumulative follow-up period of 2,333 patient months (194.4 patient years), failure of the pacing circuit occurred in 3 patients at 21, 25, and 27 months, respectively. Nine patients had difficulty accepting the recharging concept and, in 3 of these patients, it became necessary to replace the rechargeable generator with a conventional energy source. The overall failure rate of approximately 3% per year (including the 3 patients in whom it was necessary to remove the generator because of failure to recharge properly), coupled with the inconvenience of recharging, limits the usefulness of the rechargeable system compared to the newer lithium-powered generator. PMID:83632

Stertzer, S H; DePasquale, N P; Cohn, L J; Bruno, M S

1978-04-01

437

Pacemaker lead infection: report of three cases and review of the literature  

PubMed Central

Pacemaker lead infection is a rare condition, most often occurring when intervention is needed after pacemaker implantation. Diagnosis is by blood cultures and confirmation by transoesophageal echocardiography; transthoracic echocardiography is often inadequate. A literature review indicated the microorganism most responsible for late lead infection is Staphylococcus epidermidis (which can grow on plastic material). A retrospective analysis of patient files from the authors' institution (1993-97) yielded three patients with proven pacemaker lead endocarditis. The diagnosis of pacemaker endocarditis was by transoesophageal echocardiography. The endocarditis appeared after a long period and in two of the three patients there was S epidermidis infection. Thoracotomy with removal of the infected system was performed because of the large dimensions of the vegetations. A new pacemaker was implanted: in one patient with endocardial leads, in the other two with epicardial leads. All three patients recovered well and follow up was uneventful for at least one year.?? Keywords: endocarditis;  pacemaker lead infection;  staphylococci;  transoesophageal echocardiography

Voet, J; Vandekerckhove, Y; Muyldermans, L; Missault, L; Matthys, L

1999-01-01

438

Haemophilus parainfluenzae bacteremia associated with a pacemaker wire localized by gallium scan  

SciTech Connect

A young woman with a history of sick sinus syndrome and placement of a permanent pacemaker 6 months before admission had fever and Haemophilus parainfluenzae bacteremia. A gallium scan localized the infection to the site of the pacemaker wire. Echocardiograms were negative for any vegetations. The patient responded to cefotaxime and trimethoprim-sulfamethoxazole therapy. We believe that this is the first case of H. parainfluenzae bacteremia associated with a pacemaker wire and localized by gallium scan.

Rosenbaum, G.S.; Calubiran, O.; Cunha, B.A. (Winthrop-Univ. Hospital, Mineola, NY (USA))

1990-05-01

439

Self-Organized Pacemakers in a Coupled Reaction-Diffusion-Mechanics System  

NASA Astrophysics Data System (ADS)

Using a computational model of a coupled reaction-diffusion-mechanics system, we find that mechanical deformation can induce automatic pacemaking activity. Pacemaking is shown to occur after a single electrical or mechanical stimulus in an otherwise nonoscillatory medium. We study the mechanisms underpinning this effect and conditions for its existence. We show that self-organized pacemakers drift throughout the medium to approach attractors with locations that depend on the size of the medium, and on the location of the initial stimulus.

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

2005-12-01

440

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

441

Tricuspid-valve repair for pacemaker leads endocarditis  

PubMed Central

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

Iezzi, Federica; Cini, Roberto; Sordini, Paolo

2010-01-01

442

Persistent left superior vena cava and pacemaker implantation  

PubMed Central

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.

Pontillo, Daniele; Patruno, Nicolino

2013-01-01

443

Secure pacemaker fixation critical for prevention of Twiddler's syndrome.  

PubMed

A two year old, female spayed border collie presented three weeks after permanent pacemaker implantation for weakness, lethargy and collapse. Electrocardiogram documented complete (3(rd) degree) atrioventricular (AV) block, the absence of pacing and a ventricular escape rhythm. Thoracic radiographs revealed retraction and dislodgement of the passive fixation lead from the right ventricular apex. During a procedure to reposition the lead, it was noted that lead retraction had resulted from rotation of the generator with twisting and entanglement of the lead on itself and around the generator, a complication recognized in human patients as "Twiddlers syndrome". The pacemaker lead was removed, a new lead securely placed at the right ventricular apex, and the generator was secured into a revised subcutaneous pocket. Pacing was re-established and the Twiddler's syndrome has not reoccurred. PMID:19083303

Zimmerman, Sarah A; Bright, Janice M

2004-05-01