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1

Cardiac pacemakers: an update.  

PubMed

In this update of cardiac pacing we review the new revised ACC/AHA/NASPE Guidelines for implantation of cardiac pacemakers, including selection of pacing mode, possible new indications, and other more recent advances in cardiac pacing. PMID:15008358

Johnson, Charles D; Arzola-Castañer, Daniel

2003-01-01

2

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

SciTech Connect

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

Not Available

1980-06-01

3

Trends in cardiac pacemaker batteries.  

PubMed

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

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

2004-01-01

4

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

Code of Federal Regulations, 2011 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...

2011-04-01

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

Space Derived Health Aids (Cardiac Pacemaker)  

NASA Technical Reports Server (NTRS)

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

1981-01-01

7

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

PubMed

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

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

1991-12-01

8

Mathematical Models of Cardiac Pacemaking Function  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

9

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

Code of Federal Regulations, 2010 CFR

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

2010-04-01

10

Epithermal neutron beam interference with cardiac pacemakers.  

PubMed

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

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

2011-12-01

11

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

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.  

PubMed

While electronic cardiac pacing in its various modalities represents standard of care for treatment of symptomatic bradyarrhythmias and heart failure, it has limitations ranging from absent or rudimentary autonomic modulation to severe complications. This has prompted experimental studies to design and validate a biological pacemaker that could supplement or replace electronic pacemakers. Advances in cardiac gene therapy have resulted in a number of strategies focused on beta-adrenergic receptors as well as specific ion currents that contribute to pacemaker function. This article reviews basic pacemaker physiology, as well as studies in which gene transfer approaches to develop a biological pacemaker have been designed and validated in vivo. Additional requirements and refinements necessary for successful biopacemaker function by gene transfer are discussed. PMID:17139515

Anghel, Traian M; Pogwizd, Steven M

2007-02-01

14

Functional Imaging of the Embryonic Pacemaking and Cardiac Conduction  

E-print Network

Functional Imaging of the Embryonic Pacemaking and Cardiac Conduction System Over the Past 150 ABSTRACT Early analyses of cardiac pacemaking and conduction system (CPCS) development relied on classic Ebbe et al., 1939). The events guiding the formation of a normal cardiac pacemaking and conduction

15

Automated Verification of Quantitative Properties of Cardiac Pacemaker Software  

E-print Network

Automated Verification of Quantitative Properties of Cardiac Pacemaker Software Marta Kwiatkowska that is suitable for quantitative verification of pacemakers. The heart model is formulated at the level of cardiac, such as cardiac pacemakers [6], GPCA infusion pumps [8] and continuous glucose monitors [11], are stochastic

Oxford, University of

16

On Quantitative Software Quality Assurance Methodologies for Cardiac Pacemakers  

E-print Network

On Quantitative Software Quality Assurance Methodologies for Cardiac Pacemakers Marta Kwiatkowska. Embedded software is at the heart of implantable medical de- vices such as cardiac pacemakers, and rigorous-based design; quantitative verification; hybrid au- tomata; heart modelling; cardiac pacemakers. 1 Introduction

Oxford, University of

17

Technical Series Trends in Cardiac Pacemaker Batteries  

Microsoft Academic Search

Batteries used in Implantable cardiac pacemakers-present unique challenges to their developers and manufacturers in terms of high levels of safety and reliability. In addition, the batteries must have longevity to avoid frequent replacements. Technological advances in leads\\/electrodes have reduced energy requirements by two orders of magnitude. Micro- electronics advances sharply reduce internal current drain concurrently decreasing size and increasing functionality,

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

18

[Safety rules for patients with artificial cardiac pacemaker].  

PubMed

The recent progress in cardiac pacing increased the usefulness of artificial pacemakers. The initial purpose of avoiding Stokes-Adams attacks, was changed by a complex way to completely give back the physiologic response of cardiac rate and atrioventricular synchronism. However, this process forced the patients to take care of their pacemakers, and to spend more time in follow-up procedures. Additionally, the pacemakers became more vulnerable to environmental and hospital interferences. Basic rules, for all patients, are described in this paper, in order to improve their quality of life. Follow-up procedures are related in detail. It is described how programmed electronic evaluations can contribute to avoid complications, to detect subclinic problems and to improve the patient's haemodynamics and physical capacity. It shows also how to use complementary examinations, like thoracic X-rays, exercise testing and Holter monitoring to optimize the cardiac pacing system. Interferences in pacemakers are focused with special attention to myo-potentials, environmental electromagnetic fields, and damage to system owing to medical procedures, like therapeutic radiation, defibrillation and electrocauterization. The approach to infective processes in pacemakers gives special emphasis to prevention of direct surgical contamination, erosion of the skin, and haematogenic dissemination of distant infective focus. PMID:9138363

Costa, R; Leão, M I; Décourt, L V

1996-01-01

19

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

20

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

21

Quantitative Verification of Implantable Cardiac Pacemakers Taolue Chen Marco Diciolla Marta Kwiatkowska Alexandru Mereacre  

E-print Network

Quantitative Verification of Implantable Cardiac Pacemakers Taolue Chen Marco Diciolla Marta. INTRODUCTION Implantable cardiac pacemakers (pacemakers for short) are the most commonly used cardiac rhythm pacemakers in the This work is partially supported by the ERC Advanced Grant VERI- WARE and the Institute

Oxford, University of

22

Sexual dimorphism in the complexity of cardiac pacemaker activity  

NSDL National Science Digital Library

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

Terry B. Kuo (Tzu Chi Buddhist General Hospital Department of Neurology)

2007-10-03

23

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. PMID:24106646

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

2013-01-01

24

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

25

SHOX2 Overexpression Favors Differentiation of Embryonic Stem Cells into Cardiac Pacemaker Cells, Improving Biological Pacing Ability  

PubMed Central

Summary When pluripotency factors are removed, embryonic stem cells (ESCs) undergo spontaneous differentiation, which, among other lineages, also gives rise to cardiac sublineages, including chamber cardiomyocytes and pacemaker cells. Such heterogeneity complicates the use of ESC-derived heart cells in therapeutic and diagnostic applications. We sought to direct ESCs to differentiate specifically into cardiac pacemaker cells by overexpressing a transcription factor critical for embryonic patterning of the native cardiac pacemaker (the sinoatrial node). Overexpression of SHOX2 during ESC differentiation upregulated the pacemaker gene program, resulting in enhanced automaticity in vitro and induced biological pacing upon transplantation in vivo. The accentuated automaticity is accompanied by temporally evolving changes in the effectors and regulators of Wnt signaling. Our findings provide a strategy for enriching the cardiac pacemaker cell population from ESCs. PMID:25533636

Ionta, Vittoria; Liang, Wenbin; Kim, Elizabeth H.; Rafie, Reza; Giacomello, Alessandro; Marbán, Eduardo; Cho, Hee Cheol

2014-01-01

26

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

27

Pacemakers  

NSDL National Science Digital Library

A pacemaker generates electric pulses that regulate heartbeats. This patient education program explains how pacemakers work, and the benefits and risks of having one. It also discusses what to expect after getting a pacemaker. This is a MedlinePlus Interactive Health Tutorial from the National Library of Medicine, designed and developed by the Patient Education Institute. NOTE: The tutorial requires a special Flash plug-in, version 4 or above. If you do not have Flash, you will be prompted to obtain a free download of the software before you start the tutorial. You will also need an Acrobat Reader, available as a free download, in order to view the Reference Summary.

Patient Education Institute

28

Demo abstract: Closed-loop testing for implantable cardiac pacemakers  

Microsoft Academic Search

The increasing complexity of software in implantable medical devices such as cardiac pacemakers and defibrillators accounts for over 40% of device recalls. Testing remains the principal means of verification in the medical device certification regime. Traditional software test generation techniques, where the tests are generated independently of the operational environment, are not effective as the device must be tested within

Zhihao Jiang; Miroslav Pajic; Rahul Mangharam

2011-01-01

29

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

30

Generation of Murine Cardiac Pacemaker Cell Aggregates Based on ES-Cell-Programming in Combination with Myh6-Promoter-Selection.  

PubMed

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

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

2015-01-01

31

The increased need for a permanent pacemaker after reoperative cardiac surgery  

Microsoft Academic Search

Objective: The requirement for permanent pacemaker implantation after most initial cardiac surgical procedures generally is less than 3%. To identify the incidence and factors related to permanent pacemaker need after repeat cardiac surgery, we retrospectively studied 558 consecutive patients undergoing at least one repeat cardiac operation. Method: Univariable and multivariable analyses of comorbidity, preoperative catheterization values, and operative data were

Joseph W. Lewis; Charles R. Webb; Sol D. Pickard; Judith Lehman; Gordon Jacobsen

1998-01-01

32

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

33

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

PubMed Central

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

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

2015-01-01

34

PP2 Prevents Isoproterenol Stimulation of Cardiac Pacemaker Activity.  

PubMed

: Increasing evidence has demonstrated the potential risks of cardiac arrhythmias (such as prolonged QT interval) using tyrosine kinase inhibitors for cancer therapy. We report here that a widely used selective inhibitor of Src tyrosine kinases, PP2, can inhibit and prevent isoproterenol stimulation of cardiac pacemaker activity. In dissected rat sinus node, PP2 inhibited and prevented isoproterenol stimulation of spontaneous beating rate. In isolated sinus node myocytes, PP2 suppressed the hyperpolarization-activated "funny" current (If) by negatively shifting the activation curve and decelerating activation kinetics, associated with decreased cell surface expression and reduced tyrosine phosphorylation of hyperpolarization-activated cyclic nucleotide-modulated channel 4 (HCN4) channel proteins. In human embryonic kidney 293 cells overexpressing recombinant human HCN4 channels, PP2 reversed isoproterenol stimulation of HCN4 and inhibited HCN4-573x, a cAMP-insensitive human HCN4 mutant. Isoprotenrenol had little effects on HCN4-573x. These results demonstrated that inhibition of presumably tyrosine Src kinase activity in heart by PP2 decreased and prevented the potential ?-adrenergic stimulation of cardiac pacemaker activity. These effects are mediated, at least partially, by a cAMP-independent attenuation of channel activity and cell surface expression of HCN4, the key channel protein that controls the heart rate. PMID:25658311

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

2015-02-01

35

The Cardiac Pacemaker and Conduction System Develops From Embryonic Myocardium that Retains Its Primitive Phenotype  

Microsoft Academic Search

Disorders of the cardiac conduction system occur frequently and may cause life-threatening arrhythmias requiring medication or electronic pacemaker implantation. Repair or regeneration of conduction system components is currently not possible due to limited knowledge of the molecular regulation of pacemaker myocardium. Origin and development of the cardiac conduction system have been subject to debate for many decades. This review will

Martijn L Bakker; Vincent M Christoffels; Antoon F M Moorman

2010-01-01

36

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

37

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

38

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

NASA Astrophysics Data System (ADS)

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

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

1985-11-01

39

Implantable pacemakers  

Microsoft Academic Search

Advances in cardiac pacing have greatly reduced the size of pacemakers, while improving their longevity and reliability, expanding their clinical applications and increasing their sophistication in terms of programming and automatic features. Significant reductions in the size of pacing systems have been mainly due to improvements in power sources, increased circuit integration, hybrid packaging, and the development of smaller leads

RICHARD S. SANDERS; MICHAEL T. LEE

1996-01-01

40

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

41

Advanced Pacemaker  

NASA Technical Reports Server (NTRS)

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

1990-01-01

42

Electronic pacemakers.  

PubMed

The number of patients who have cardiac pacemakers has increased markedly over the past few decades since the technology was first introduced in the 1950s. Advances in technology, expanding indications, and the aging of the population ensure that clinicians will encounter patients with cardiac pacemakers on a regular basis. This article summarizes the electrocardiographic manifestations of the normally functioning permanent cardiac pacemaker and abnormalities associated with pacemaker malfunction. PMID:16308119

Chan, Theodore C; Cardall, Taylor Y

2006-02-01

43

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

44

Programmable Pacemaker  

NASA Technical Reports Server (NTRS)

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

1996-01-01

45

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

Microsoft Academic Search

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

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

2005-01-01

46

Cardiac pacemaker dysfunction in children after thoracic drainage catheter manipulation.  

PubMed

Two children underwent placement of permanent, epicardial-lead, dual-chamber, unipolar pacemaker systems for complete heart block. Postoperatively, both patients demonstrated subcutaneous emphysema-in the area of their pulse generators-temporally related to thoracic catheter manipulation. Acutely, each situation was managed with manual compression of the pulse generator, ascertaining appropriate pacemaker sensing and pacing. Maintenance of compression with pressure dressings, vigilant observation/monitoring, and education of the care givers resulted in satisfactory pacemaker function without invasive intervention. PMID:9146348

Lobdell, K W; Walters, H L; Hudson, C; Hakimi, M

1997-05-01

47

Arc welding interference recorded by an implanted cardiac pacemaker.  

PubMed

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

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

2006-04-28

48

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

49

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

2012-12-01

50

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

NASA Astrophysics Data System (ADS)

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

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

51

[Cardiac pacemaker and internal defibrillators (ICD). Basic principles and new important developments, status 1998].  

PubMed

In recent years, treatment of cardiac arrhythmias with pacemakers and implantable cardioverter/defibrillators has become increasingly popular. Numerous technical developments have resulted in great advances in this area. International pacing letter coding for use with pacemakers defines the chamber(s) paced, the chamber in which the electrical activity is sensed, and the type of pacing. This also enables the family doctor involved in the care of the cardiac patient to identify the pacemaker system employed and provides him with initial orientation. New developments including VDD pacing, autocapture and autosensing are described and discussed. In a second part, the conditions for the use, and the manner of functioning, of modern implantable cardioverter/defibrillators are explained. PMID:9773595

Deisenhofer, I; Karch, M; Zrenner, B; Schmitt, C; Schömig, A

1998-08-20

52

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

Microsoft Academic Search

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

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

2004-01-01

53

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

54

Cardiac Pacemaking in Hong Kong: Report of a Survey of General Practitioners and Internists  

Microsoft Academic Search

A questionnaire study was carried out among cardiologists, internists, general practitioners, and final year medical students in Hong Kong concerning cardiac pacemaking. The response rate was 11.2%. Salient results include the misconception on the part of 40% and 12% of physicians, that general anesthesia and thoracotomy respectively, are commonly required for permanent pacing and that the procedure is associated with

Chu-Pak Lau; Chun-Ho Cheng; Clark Munro; Maxwell Tse; Cheuk-Kit Wong; Wing-Hung Leung

1991-01-01

55

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

Microsoft Academic Search

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

1991-01-01

56

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

PubMed Central

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

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

2014-01-01

57

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

58

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

PubMed Central

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

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

2012-01-01

59

Effects of hyperpolarizing pulses on a cardiac pacemaker cell  

Microsoft Academic Search

The authors' mathematical model of a rabbit sinoatrial node (SAN) cell (see S. Demir et al., Amer. J. Physiol., vol. 266, p. C832-52, 1994) was studied to explain the phase-sensitive response of this pacemaker cell to single and periodic pulses of hyperpolarizing electrical current. The resulting simulations were presented in phase response curves (PRCs) for the single pulse and in

Semahat S Demir; John W Clark; Wayne R Giles

1997-01-01

60

First-degree atrioventricular block. Clinical manifestations, indications for pacing, pacemaker management & consequences during cardiac resynchronization.  

PubMed

Marked first-degree AV block (PR> or =0.30 s) can produce a clinical condition similar to that of the pacemaker syndrome. Clinical evaluation often requires a treadmill stress test because patients are more likely to become symptomatic with mild or moderate exercise when the PR interval cannot adapt appropriately. Uncontrolled studies have shown that many such symptomatic patients with normal left ventricular (LV) function improve with conventional dual chamber pacing (Class IIa indication). In contrast, marked first-degree AV block with LV systolic dysfunction and heart failure is still a Class IIb indication, a recommendation that is now questionable because a conventional DDD(R) pacemaker would be committed to right ventricular pacing (and its attendant risks) virtually 100% of the time. It would seem prudent at this juncture to consider a biventricular DDD device in this situation. Patients with suboptimally programmed pacemakers may develop functional atrial undersensing because the P wave tends to migrate easily into the postventricular atrial refractory period (PVARP). Retrograde vetriculoatrial conduction block is uncommon in marked first-degree AV block so a relatively short PVARP can often be used at rest with little risk of endless loop tachycardia. The usefulness of a short PVARP may be negated by special PVARP functions in some pulse generators designed to time out a long PVARP at rest and a gradually shorter one with activity. First-degree AV block during cardiac resynchronization therapy (CRT) predisposes to loss of ventricular resynchronization during biventricular pacing because it favors the initiation of electrical "desynchronization" especially in association with a relatively fast atrial rate and a relatively slow programmed upper rate. Patients with first-degree AV block have a poorer outcome with CRT than patients with a normal PR interval, a response that may involve several mechanisms. (1) The long PR interval may be a marker of more advanced heart disease. (2) Patients with first-degree AV block may experience more episodes of undetected "electrical desynchronization". (3) "Concealed resynchronization" whereupon ventricular activation in patients with a normal PR interval may result from fusion of electrical wavefronts coming from the right bundle branch and the impulse from the LV electrode. The resultant hemodynamic response may be superior because the detrimental effects of right ventricular stimulation (required in the setting of a longer PR interval) are avoided. PMID:17334913

Barold, S Serge; Ilercil, Arzu; Leonelli, Fabio; Herweg, Bengt

2006-11-01

61

Pacemakers.  

PubMed

Rapid advances in pacing technology will continue to affect the quality of life of many patients with cardiovascular disease. A truly "smart" device that seemed fanciful 30 years ago now seems to be a virtual certainty by early in the next century. The surgical contributions and expertise of individuals trained in cardiothoracic surgery in these bradypacing developments is highly desirable to minimize morbidity to the greatest possible degree, to optimize the outcome of the procedure for the individual patient, and to conserve health care costs as much as possible. To maintain this cardiothoracic presence in cardiac pacing, acquisition of knowledge and expertise in the basic electrophysiology and technology of cardiac pacing, to go along with surgical expertise, is necessary on the part of individuals with the interest and opportunity to do so. PMID:9001543

Ferguson, T B

1997-01-01

62

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

63

Choosing pacemakers appropriately  

Microsoft Academic Search

The range of implantable cardiac pacing devices has expanded, with the advances in available technology. Indications for cardiac pacing devices, that is pacemakers, implantable cardioverter defibrillators (ICDs) and cardiac resynchronisation therapy devices (CRTs), have expanded for the treatment, diagnosis and monitoring of bradycardia, tachycardia and heart failure. While the need for pacemakers is increasing, not all patients who require pacemakers

G K Panicker; B Desai; Y Lokhandwala

2009-01-01

64

Cardiac Pacemaker Activity: From Single Cells to Modelling the Heart  

Microsoft Academic Search

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

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

65

Programmable Pacemaker  

NASA Technical Reports Server (NTRS)

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

1980-01-01

66

Angiotensin II promotes differentiation of mouse c-kit-positive cardiac stem cells into pacemaker-like cells  

PubMed Central

Cardiac stem cells (CSCs) can differentiate into cardiac muscle-like cells; however, it remains unknown whether CSCs may possess the ability to differentiate into pacemaker cells. The aim of the present study was to determine whether angiotensin II (Ang II) could promote the specialization of CSCs into pacemaker-like cells. Mouse CSCs were treated with Ang II from day 3–5, after cell sorting. The differentiation potential of the cells was then analyzed by morphological analysis, flow cytometry, reverse transcription-polymerase chain reaction, immunohistochemistry and patch clamp analysis. Treatment with Ang II resulted in an increased number of cardiac muscle-like cells (32.7±4.8% vs. 21.5±4.8%; P<0.05), and inhibition of smooth muscle-like cells (6.2±7.3% vs. 20.5±5.1%; P<0.05). Following treatment with Ang II, increased levels of the cardiac progenitor-specific markers GATA4 and Nkx2.5 were observed in the cells. Furthermore, the transcript levels of pacemaker function-related genes, including hyperpolarization-activated cyclic nucleotide-gated (HCN)2, HCN4, T-box (Tbx)2 and Tbx3, were significantly upregulated. Immunofluorescence analysis confirmed the increased number of pacemaker-like cells. The pacemaker current (If) was recorded in the cells derived from CSCs, treated with Ang II. In conclusion, treatment of CSCs with Ang II during the differentiation process modified cardiac-specific gene expression and resulted in the enhanced formation of pacemaker-like cells. PMID:25572000

XUE, CHENG; ZHANG, JUN; LV, ZHAN; LIU, HUI; HUANG, CONGXIN; YANG, JING; WANG, TEN

2015-01-01

67

Angiotensin II promotes differentiation of mouse c-kit-positive cardiac stem cells into pacemaker-like cells.  

PubMed

Cardiac stem cells (CSCs) can differentiate into cardiac muscle?like cells; however, it remains unknown whether CSCs may possess the ability to differentiate into pacemaker cells. The aim of the present study was to determine whether angiotensin II (Ang II) could promote the specialization of CSCs into pacemaker?like cells. Mouse CSCs were treated with Ang II from day 3?5, after cell sorting. The differentiation potential of the cells was then analyzed by morphological analysis, flow cytometry, reverse transcription?polymerase chain reaction, immunohistochemistry and patch clamp analysis. Treatment with Ang II resulted in an increased number of cardiac muscle?like cells (32.7±4.8% vs. 21.5±4.8%; P<0.05), and inhibition of smooth muscle?like cells (6.2±7.3% vs. 20.5±5.1%; P<0.05). Following treatment with Ang II, increased levels of the cardiac progenitor?specific markers GATA4 and Nkx2.5 were observed in the cells. Furthermore, the transcript levels of pacemaker function?related genes, including hyperpolarization?activated cyclic nucleotide?gated (HCN)2, HCN4, T?box (Tbx)2 and Tbx3, were significantly upregulated. Immunofluorescence analysis confirmed the increased number of pacemaker?like cells. The pacemaker current (If) was recorded in the cells derived from CSCs, treated with Ang II. In conclusion, treatment of CSCs with Ang II during the differentiation process modified cardiac?specific gene expression and resulted in the enhanced formation of pacemaker?like cells. PMID:25572000

Xue, Cheng; Zhang, Jun; Lv, Zhan; Liu, Hui; Huang, Congxin; Yang, Jing; Wang, Ten

2015-05-01

68

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

PubMed Central

Background Conventional cardiac pacemakers are still often regarded as a contraindication to magnetic resonance imaging (MRI). We conducted this study to support the hypothesis that it is safe to scan patients with cardiac pacemakers in a 1.5 Tesla MRI, if close supervision and monitoring as well as adequate pre- and postscan programming is provided. Methods We followed up 356 patients (age 61.3?±?9.1 yrs., 229 men) with single (n?=?132) or dual chamber (n?=?224) cardiac pacemakers and urgent indication for a cranial MRI for 12 months. The scans were performed at 1.5T. During the scan patients were monitored with a 3-lead ECG and pulse oximetry. Prior to the scan pacemakers were programmed according to our own protocol. Results All 356 scans were completed without complications. No arrhythmias were induced, programmed parameters remained unchanged. No pacemaker dysfunction was identified. Follow-up examinations were performed immediately, 2 weeks, 2, 6, and 12 months after the scan. There was no significant change of pacing capture threshold (ventricular 0.9?±?0.4 V@0.4 ms, atrial 0.9?±?0.3 V@0.4 ms) immediately (ventricular 1.0?±?0.3 V@0.4 ms, atrial 0.9?±?0.4 V@0.4 ms) or at 12 months follow-up examinations (ventricular 0.9?±?0.2 V@0.4 ms, atrial 0.9?±?0.3 V@0.4 ms). There was no significant change in sensing threshold (8.0?±?4.0 mV vs. 8.1?±?4.2 mV ventricular lead, 2.0?±?0.9 mV vs. 2.1?±?1.0 mV atrial lead) or lead impedance (ventricular 584?±?179?? vs. 578?±?188??, atrial 534?±?176?? vs. 532?±?169??) after 12 months. Conclusions This supports the evidence that patients with conventional pacemakers can safely undergo cranial MRI in a 1.5T system with suitable preparation, supervision and precautions. Long term follow-up did not reveal significant changes in pacing capture nor sensing threshold. PMID:24903354

2014-01-01

69

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

PubMed

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

Scholten, A; Silny, J

2001-01-01

70

Worsening Heart Failure as the Main Manifestation of Neglected Complete Extrusion of a Cardiac Resynchronization Therapy Pacemaker  

Microsoft Academic Search

A patient with dilated cardiomyopathy presented at the emergency department with a completely extruded cardiac resynchronization therapy pacemaker, complaining of worsening dyspnea. The device was functioning intermittently, and no evidence of local or systemic inflammation was observed. The patient had been living with the device hanging against his chest for several weeks and he eventually sought medical assistance because of

Vassilios P. Vassilikos; Aglaia-Angeliki Mantziari; Georgios Stavropoulos; Ioannis H. Styliadis

2010-01-01

71

A fully integrated two-channel A\\/D interface for the acquisition of cardiac signals in implantable pacemakers  

Microsoft Academic Search

This work presents an input stage for a cardiac pacemaker fully integrated in 0.35µm CMOS technology. The system can acquire and digitize to 8 bits both atrial and ventricular electrical activity. Log-domain circuits are exploited to amplify and filter the input signal, while ?? modulation is exploited to convert it. The design is power optimized, indeed the power consumption is

Andrea Gerosa; Andrea Maniero; Andrea Neviani

2004-01-01

72

A fully-integrated two-channel A\\/D interface for the acquisition of cardiac signals in implantable pacemakers  

Microsoft Academic Search

This work presents an input stage for a cardiac pacemaker fully integrated in a 0.35?m CMOS technology. The system can acquire and digitize to 8 bits both atrial and ventricular electrical activity. Log-domain circuits are exploited to amplify and filter the input signal, while ?? modulation is exploited to convert it. The design is power optimized, indeed the power consumption

Andrea Gerosa; Andrea Maniero; Andrea Neviani

2003-01-01

73

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 ...

74

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

NASA Astrophysics Data System (ADS)

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

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

2009-06-01

75

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

2011-01-01

76

Inhibition of cardiac pacemaker channel hHCN2 depends on intercalation of lipopolysaccharide into channel-containing membrane microdomains  

PubMed Central

Depressed heart rate variability in severe inflammatory diseases can be partially explained by the lipopolysaccharide (LPS)-dependent modulation of cardiac pacemaker channels. Recently, we showed that LPS inhibits pacemaker current in sinoatrial node cells and in HEK293 cells expressing cloned pacemaker channels, respectively. The present study was designed to verify whether this inhibition involves LPS-dependent intracellular signalling and to identify structures of LPS responsible for pacemaker current modulation. We examined the effect of LPS on the activity of human hyperpolarization-activated cyclic nucleotide-gated channel 2 (hHCN2) stably expressed in HEK293 cells. In whole-cell recordings, bath application of LPS decreased pacemaker current (IhHCN2) amplitude. The same protocol had no effect on channel activity in cell-attached patch recordings, in which channels are protected from the LPS-containing bath solution. This demonstrates that LPS must interact directly with or close to the channel protein. After cleavage of LPS into lipid A and the polysaccharide chain, neither of them alone impaired IhHCN2, which suggests that modulation of channel activity critically depends on the integrity of the entire LPS molecule. We furthermore showed that ?-cyclodextrin interfered with LPS-dependent channel modulation predominantly via scavenging of lipid A, thereby abrogating the capability of LPS to intercalate into target cell membranes. We conclude that LPS impairs IhHCN2 by a local mechanism that is restricted to the vicinity of the channels. Furthermore, intercalation of lipid A into target cell membranes is a prerequisite for the inhibition that is suggested to depend on the direct interaction of the LPS polysaccharide chain with cardiac pacemaker channels. PMID:24366264

Klöckner, Udo; Rueckschloss, Uwe; Grossmann, Claudia; Matzat, Saskia; Schumann, Katja; Ebelt, Henning; Müller-Werdan, Ursula; Loppnow, Harald; Werdan, Karl; Gekle, Michael

2014-01-01

77

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

PubMed

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

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

2014-12-01

78

Arrhythmia and Cardiac Electrophysiology Objectives Understand the indications, function, and troubleshooting of pacemakers and  

E-print Network

, function, and troubleshooting of pacemakers and ICDs. · Diagnose and treat common arrhythmias · The trainee should be able to interrogate and assess the function of pacemakers and ICD's. · The trainee, be able to implant pacemakers and ICDs. Teaching Methods · Active participation during daily morning EP

Ford, James

79

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

80

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

81

A fully integrated dual-channel log-domain programmable preamplifier and filter for an implantable cardiac pacemaker  

Microsoft Academic Search

A programmable-gain preamplifier and filter for detection of spontaneous heart activity in an implantable cardiac pacemaker is presented. The system is fully integrated in a standard 0.35-?m CMOS technology, including all auxiliary circuits. Two channels are available in order to process both atrial and ventricular signals. CMOS translinear circuits, with particular emphasis on log-domain techniques, have been exploited in order

Andrea Gerosa; Andrea Maniero; Andrea Neviani

2004-01-01

82

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

83

Permanent pacemakers in pregnancy.  

PubMed

Advances in cardiology and cardiovascular surgery have increased the use of permanent pacemakers in young adults such that there are more women with pacemakers becoming pregnant. This case report describes the pregnancy and delivery of a young woman with a demand pacemaker and reviews the principles of management of cardiac pacemakers in pregnancy. As part of the multidisciplinary team including cardiology, anesthesia, nursing and caring for these patients, it is important that obstetricians be informed and follow the principles of management of cardiac pacemakers in pregnancy to continue to achieve successful pregnancy outcomes. PMID:21995172

Coolen, J; Turnelp, R; Vonder Muhll, I; Chandra, S

2011-01-01

84

Atrioventricular delays, cardiac output and diastolic function in patients with implanted dual chamber pacing and sensing pacemakers.  

PubMed

The Cardiac Output (CO), Filling Time (FT) and Myocardial Performance Index (MPI) derived optimal atrioventricular delay (AVD), were compared and systolic and diastolic performance at every optimal AVD were analyzed. Thirty-two patients with implanted DDD pacemaker were investigated from implantation time to 6 months following PM implantation, in Cardiovascular Research Center of Tabriz University of Medical Sciences. The evaluation was performed during AV sequential pacing with different programmed AVDS ranged from 100 to 200 msec by steps of 20-30 msec. At every AVD, the following parameters were measured: FT, mitral VTI, ET, aortic VTI, ICT and IRT. CO and FT derived optimal AVDs were significantly different (146 +/- 37 and 126 +/- 35 msec, respectively), but their difference with MPI derived optimal AVDs was not significant (130 +/- 28 msec). ICT/ET was similar at CO, FT and MPI derived optimal AVD (0.24 +/- 0.10, 0.22 +/- 0.05 and 0.20 +/- 0.07, respectively). IRT/ET ratio was similar at CO, FT and MPI derived optimal AVDs (0.46 +/- 0.14, 0.45 +/- 0.10 and 0.42 +/- 0.10, respectively). Different methods indicate different optimal AVDs. However analysis of systolic and diastolic performance shows that different AVDs result in similar systolic or diastolic performance. At MPI optimized AVD, a high CO combined with the most advantageous conditions of both isovolumic contraction and relaxation phases is achieved. PMID:19137850

Akbarzadeh, F; Toufan, Mehrnoush

2008-10-15

85

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

86

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

87

Successful radiation treatment of anaplastic thyroid carcinoma metastatic to the right cardiac atrium and ventricle in a pacemaker-dependent patient  

PubMed Central

Anaplastic thyroid carcinoma (ATC) is a rare, aggressive malignancy, which is known to metastasize to the heart. We report a case of a patient with ATC with metastatic involvement of the pacemaker leads within the right atrium and right ventricle. The patient survived external beam radiation treatment to his heart, with a radiographic response to treatment. Cardiac metastases are usually reported on autopsy; to our knowledge, this is the first report of the successful treatment of cardiac metastases encasing the leads of a pacemaker, and of cardiac metastases from ATCs, with a review of the pertinent literature. PMID:21320341

2011-01-01

88

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

89

SR Ca 2+ store refill—a key factor in cardiac pacemaking  

Microsoft Academic Search

This study presents a theoretical analysis of the role of store Ca2+ uptake on sinoatrial node (SAN) cell pacemaking. Two mechanisms have been shown to be involved in SAN pacemaking, these being: 1) the membrane oscillator model where rhythm generation is based on the interaction of voltage-dependent membrane ion channels and, 2) the store oscillator model where cyclical release of

Mohammad S. Imtiaz; Pierre-Yves von der Weid; Derek R. Laver; Dirk F. van Helden

2010-01-01

90

In-vitro experiments to estimate the impact of EMI from cellular phone and base-station antennas on implantable cardiac pacemakers  

Microsoft Academic Search

This paper reviews the in-vitro experiments made to estimate the impact of the EMI from cellular phones on implantable cardiac pacemakers in Japan. The approach of the EMI test system is to directly expose the pacemaker to the near- and far-fields generated by a dipole antenna and\\/or an actual cellular phone. The results were used by the electric medical equipment

Yoshiaki Tarusawa; T. Nojima; T. Toyoshima

2002-01-01

91

Shockwave lithotripsy and pacemakers: experience with 20 cases.  

PubMed

Lithotripsy treatment of urinary tract calculi initially excluded patients with cardiac pacemakers. Continued research and clinical study of patient outcomes has promoted a change in that initial concept. The Oklahoma Lithotripsy Center has successfully treated 20 patients with various types of pacemakers. No significant cardiovascular events occurred during treatment. Patients should be evaluated before the procedure by a cardiologist, and dual-chamber pacemakers should be reprogrammed to the single-chamber mode. Patients who cannot tolerate this should not undergo SWL. Rate-responsive pacemakers should be programmed to the non-rate-responsive (VVI) mode. The pacemaker should be at least 5 cm from the blast path. With these precautions and careful monitoring, SWL can be performed safely in most patients with pacemakers. PMID:8535456

Albers, D D; Lybrand, F E; Axton, J C; Wendelken, J R

1995-08-01

92

Induced voltage to an implantable cardiac pacemaker in a voxcel human model by a near-field intra-body communication device  

Microsoft Academic Search

The interference voltage at the terminals of a unipolar-type implantable cardiac pacemaker induced by a nearfield intra-body communication device was investigated by numerical calculations. Operating frequency was assumed 5 MHz. The dependency of induced voltage on the electrical constants of a realistic human model was examined. The results showed that the induced voltage was inversely proportional to the absolute value

Yuki Yoshino; Masao Taki; Akinori Furuya; Nobutaro Shibata; Mitsuru Shinagawa; Mitsuo Hattori

2011-01-01

93

Electromagnetic and radiation environment effects on pacemakers  

Microsoft Academic Search

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

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

1999-01-01

94

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

PubMed

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. PMID:19166829

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

2009-03-15

95

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

PubMed

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

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

2010-07-01

96

An Intelligent System for Pacemaker Reprogramming  

E-print Network

a cardiac pacemaker can be described in terms similar to those used for describing diagnostic problem required. One of the possible treatments for these patients is assistance by a cardiac pacemaker. Modern of intelligent decision support is needed in order to let patients benefit from further advances in pacemaker

Lucas, Peter

97

An Intelligent System for Pacemaker Reprogramming  

E-print Network

a cardiac pacemaker can be described in terms similar to those used for describing diagnostic problem is nevertheless required. One of the possible treatments for these patients is assistance by a cardiac pacemaker in order to let patients benefit from further advances in pacemaker technology. The process

Utrecht, Universiteit

98

A Matlab program to quantify low-SNR pacemaker signals M. Lipphardt, F. Eberhardt*, U.K.H. Wiegand* and U.G. Hofmann  

E-print Network

on ventricular far-field oversensing, we have chosen to analyse signals recorded directly from the patients cardiac pacemaker, via its programmer unit, to a digital acquisition board under several test conditions Matlab routines were tested on several patients with a DDDR type pacemaker, but an extensive study under

Lübeck, Universität zu

99

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

PubMed Central

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

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

2014-01-01

100

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

101

A 1.8-?W sigma-delta modulator for 8-bit digitization of cardiac signals in implantable pacemakers operating down to 1.8 V  

Microsoft Academic Search

Implantable biomedical devices can highly benefit from submicrometer CMOS technologies both in terms of duration-time increase and size shrinking. This work shows how design techniques for submicrometer CMOS technologies lead to improvements in the sensing stage of a cardiac implantable pacemaker. A sigma-delta modulator is presented for 8-bit quantization of the natural electrical activity of the heart, fabricated in a

Andrea Gerosa; Andrea Neviani

2005-01-01

102

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

103

Program Overview The Cardiac Sonography program prepares individuals to perform cardiac  

E-print Network

Program Overview The Cardiac Sonography program prepares individuals to perform cardiac sonography disease management. The program includes instruction in reviewing and recording patient histories and clinical data, patient care, investigative and examination procedures, diagnostic procedures, data analysis

Cheng, Mei-Fang

104

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

105

Relation between QT interval and heart rate. New design of physiologically adaptive cardiac pacemaker  

Microsoft Academic Search

The relation between QT interval and heart rate has been studied in a group of patients undergoing physiological exercise, in a group undergoing atrial pacing without exercise, and in a group with complete heart block undergoing exercise at a fixed ventricular rate controlled by cardiac pacing. The expected shortening in QT interval during physiological exercise is only in part the

A F Rickards; J Norman

1981-01-01

106

Pacemakers—A journey through the years  

Microsoft Academic Search

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

Tarun Mittal

2005-01-01

107

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

PubMed Central

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

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

2014-01-01

108

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

Microsoft Academic Search

Insulation coating was added to the external pacemaker surface to prevent unnecessary electric current leakage to the periphery because the pulse generator body is used as an anode in unipolar pacing. However, a model without insulation coating has recently been used, so we studied the effects on muscle potential inhibition and muscle stimulation of pacemakers in unipolar pacing with different

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

2005-01-01

109

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

PubMed

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

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

2015-04-01

110

Initial efficacy of a cardiac rehabilitation transition program: Cardiac TRUST.  

PubMed

The purpose of this pilot study was to test the initial efficacy, feasibility, and safety of a specially designed postacute care transitional rehabilitation intervention for cardiac patients. Cardiac Transitional Rehabilitation Using Self-Management Techniques (Cardiac TRUST) is a family-focused intervention that includes progressive low-intensity walking and education in self-management skills to facilitate recovery following a cardiac event. Using a randomized two-group design, exercise self-efficacy, steps walked, and participation in an outpatient cardiac rehabilitation (CR) program were compared in a sample of 38 older adults (17 Cardiac TRUST, 21 usual care). At discharge from postacute care, the intervention group trended toward higher levels of self-efficacy for exercise outcomes than the usual care group. During the 6 weeks following discharge, the intervention group had greater attendance in outpatient CR and a trend toward more steps walked during the first week. The feasibility of the intervention was better for the home health care participants than for those in the skilled nursing facility. The provision of CR during postacute care has the potential to bridge the gap in transitional services from hospitalization to outpatient CR for these patients at high risk for future cardiac events. Further evidence of the efficacy of Cardiac TRUST is warranted. PMID:22084960

Dolansky, Mary A; Zullo, Melissa D; Boxer, Rebecca S; Moore, Shirley M

2011-12-01

111

A Prediction Framework for Cardiac Resynchronization Therapy via 4D Cardiac Motion Analysis  

E-print Network

A Prediction Framework for Cardiac Resynchronization Therapy via 4D Cardiac Motion Analysis Heng and its result can be used to assist pacemaker implantation and programming in cardiac resynchronization therapy (CRT), a widely adopted therapy for heart failure patients. In a traditional CRT device deployment

Huang, Heng

112

Pacemaker (image)  

MedlinePLUS

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

113

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. PMID:17141921

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

2009-01-01

114

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

PubMed

Recent evidence supports the idea that robust and, importantly, FLEXIBLE automaticity of cardiac pacemaker cells is conferred by a coupled system of membrane ion currents (an "M-clock") and a sarcoplasmic reticulum (SR)-based Ca(2+) oscillator ("Ca(2+)clock") that generates spontaneous diastolic Ca(2+) releases. This study identified numerical models of a human biological pacemaker that features robust and flexible automaticity generated by a minimal set of electrogenic proteins and a Ca(2+)clock. Following the Occam's razor principle (principle of parsimony), M-clock components of unknown molecular origin were excluded from Maltsev-Lakatta pacemaker cell model and thirteen different model types of only 4 or 5 components were derived and explored by a parametric sensitivity analysis. The extended ranges of SR Ca(2+) pumping (i.e. Ca(2+)clock performance) and conductance of ion currents were sampled, yielding a large variety of parameter combination, i.e. specific model sets. We tested each set's ability to simulate autonomic modulation of human heart rate (minimum rate of 50 to 70bpm; maximum rate of 140 to 210bpm) in response to stimulation of cholinergic and ?-adrenergic receptors. We found that only those models that include a Ca(2+)clock (including the minimal 4-parameter model "ICaL+IKr+INCX+Ca(2+)clock") were able to reproduce the full range of autonomic modulation. Inclusion of If or ICaT decreased the flexibility, but increased the robustness of the models (a relatively larger number of sets did not fail during testing). The new models comprised of components with clear molecular identity (i.e. lacking IbNa & Ist) portray a more realistic pacemaking: A smaller Na(+) influx is expected to demand less energy for Na(+) extrusion. The new large database of the reduced coupled-clock numerical models may serve as a useful tool for the design of biological pacemakers. It will also provide a conceptual basis for a general theory of robust, flexible, and energy-efficient pacemaking based on realistic components. PMID:23507256

Maltsev, Victor A; Lakatta, Edward G

2013-06-01

115

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

PubMed Central

Background Constant flow and concentration CO2 has previously been efficacious in attenuating ventilatory oscillations in periodic breathing (PB) where oscillations in CO2 drive ventilatory oscillations. However, it has the undesirable effect of increasing end-tidal CO2, and ventilation. We tested, in a model of PB, a dynamic CO2 therapy that aims to attenuate pacemaker-induced ventilatory oscillations while minimising CO2 dose. Methods First, pacemakers were manipulated in 12 pacemaker recipients, 6 with heart failure (ejection fraction (EF)=23.7±7.3%) and 6 without heart failure, to experimentally induce PB. Second, we applied a real-time algorithm of pre-emptive dynamic exogenous CO2 administration, and tested different timings. Results We found that cardiac output alternation using pacemakers successfully induced PB. Dynamic CO2 therapy, when delivered coincident with hyperventilation, attenuated 57% of the experimentally induced oscillations in end-tidal CO2: SD/mean 0.06±0.01 untreated versus 0.04±0.01 with treatment (p<0.0001) and 0.02±0.01 in baseline non-modified breathing. This translated to a 56% reduction in induced ventilatory oscillations: SD/mean 0.19±0.09 untreated versus 0.14±0.06 with treatment (p=0.001) and 0.10±0.03 at baseline. Of note, end-tidal CO2 did not significantly rise when dynamic CO2 was applied to the model (4.84±0.47 vs 4.91± 0.45?kPa, p=0.08). Furthermore, mean ventilation was also not significantly increased by dynamic CO2 compared with untreated (7.8±1.2 vs 8.4±1.2?L/min, p=0.17). Conclusions Cardiac pacemaker manipulation can be used to induce PB experimentally. In this induced PB, delivering CO2 coincident with hyperventilation, ventilatory oscillations can be substantially attenuated without a significant increase in end-tidal CO2 or ventilation. Dynamic CO2 administration might be developed into a clinical treatment for PB. Trial Registration number ISRCTN29344450. PMID:25332798

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

2014-01-01

116

Mapping Cardiac Pacemaker Circuits: Methodological Puzzles of the Sino-Atrial Node Optical Mapping  

PubMed Central

Historically, milestones in science are usually associated with methodological breakthroughs. Likewise, the advent of electrocardiography, microelectrode recordings and more recently optical mapping have ushered in new periods of significance of advancement in elucidating basic mechanisms in cardiac electrophysiology. As with any novel technique, however, data interpretation is challenging and should be approached with caution, as it cannot be simply extrapolated from previously used methodologies and with experience and time eventually becomes validated. A good example of this is the use of optical mapping in the sinoatrial node (SAN): when microelectrode and optical recordings are obtained from the same site in myocardium, significantly different results may be noted with respect to signal morphology and as a result have to be interpreted by a different set of principles. Given the rapid spread of the use of optical mapping, careful evaluation must be made in terms of methodology with respect to interpretation of data gathered by optical sensors from fluorescent potential-sensitive dyes. Different interpretations of experimental data may lead to different mechanistic conclusions. This review attempts to address the origin and interpretation of the “double component” morphology in the optical action potentials obtained from the SAN region. One view is that these two components represent distinctive signals from the sinoatrial node and atrial cells, and can be fully separated with signal processing. A second view is that the first component preceding the phase 0 activation represents the membrane currents and intracellular calcium transients induced diastolic depolarization from the SAN. While the consensus from both groups is that ionic mechanisms, namely the joint action of the membrane and calcium automaticity, are important in the SAN function, it is unresolved whether the double-component originates from the recording methodology or represents the underlying physiology. This overview aims to advance a common understanding of the basic principles of optical mapping in complex three-dimensional anatomical structures. PMID:20133911

Efimov, Igor R.; Fedorov, Vadim V.; Joung, Boyoung; Lin, Shien-Fong

2009-01-01

117

Apparent discontinuities in the phase-resetting response of cardiac pacemakers.  

PubMed

Injection of a brief stimulus pulse resets the spontaneous periodic activity of a sinoatrial node cell: a stimulus delivered early in the cycle generally delays the time of occurrence of the next action potential, while the same stimulus delivered later causes an advance. We investigate resetting in two models, one with a slow upstroke velocity and the other with a fast upstroke velocity, representing central and peripheral nodal cells, respectively. We first formulate each of these models as a classic Hodgkin-Huxley type of model and then as a model representing a population of single channels. In the Hodgkin-Huxley-type model of the slow-upstroke cell the transition from delay to advance is steep but continuous. In the corresponding single-channel model, due to the channel noise then present, repeated resetting runs at a fixed stimulus timing within the transitional range of coupling intervals lead to responses that span a range of advances and delays. In contrast, in the fast-upstroke model the transition from advance to delay is very abrupt in both classes of model, as it is in experiments on some cardiac preparations ("all-or-none" depolarization). We reduce the fast-upstroke model from the original seven-dimensional system to a three-dimensional system. The abrupt transition occurs in this reduced model when a stimulus transports the state point to one side or the other of the stable manifold of the trajectory corresponding to the eigendirection associated with the smaller of two positive eigenvalues. This stable manifold is close to the slow manifold, and so canard trajectories are seen. Our results demonstrate that the resetting response is fundamentally continuous, but extremely delicate, and thus suggest one way in which one can account for experimental discontinuities in the resetting response of a nonlinear oscillator. PMID:15363672

Krogh-Madsen, T; Glass, L; Doedel, E J; Guevara, M R

2004-10-21

118

Selective interference with pacemaker activity by electrical dental devices  

Microsoft Academic Search

Objective. We sought to determine whether electromagnetic interference with cardiac pacemakers occurs during the operation of contemporary electrical dental equipment.Study Design. Fourteen electrical dental devices were tested in vitro for their ability to interfere with the function of two Medtronics cardiac pacemakers (one a dual-chamber, bipolar Thera 7942 pacemaker, the other a single-chamber, unipolar Minix 8340 pacemaker). Atrial and ventricular

Craig S Miller; Fabio M Leonelli; Emma Latham

1998-01-01

119

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

Microsoft Academic Search

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

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

2009-01-01

120

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

121

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

122

Electrocautery-induced pacemaker malfunction during surgery.  

PubMed

We report a case of electrocautery-induced pacemaker failure that resulted in asystole in a 15-year-old girl scheduled for cardiac surgery. Her pacemaker was converted to the asynchronous mode the night before surgery. Electromagnetic interference from the unipolar electrocautery caused a reduction in the battery voltage, which allowed the digital circuitry, but not the voltage control oscillator (VCO), to work properly. Eventually the battery current drain caused VCO "lock-out," and pacemaker and battery failure. This report demonstrates that electrocautery-induced pacemaker failure can occur, even after conversion to asynchronous mode. PMID:1934215

Mangar, D; Atlas, G M; Kane, P B

1991-07-01

123

The Evolution of Pacemakers: An Electronics Perspective  

Microsoft Academic Search

A brief overview of the history and development of circuit designs applied in cardiac pacemakers is presented in Chapter 2.\\u000a The advances in integrated circuit designs have resulted in, for instance, diagnostic analysis, adaptive rate response and\\u000a programmability. Also, based on future trends for pacemakers, some features and improvements for modern cardiac sensing systems\\u000a are described and we point out

Sandro A. P. Haddad; Wouter A. Serdijn

124

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

125

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

126

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

127

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

128

IEEE SENSORS JOURNAL, VOL. 12, NO. 6, JUNE 2012 1817 Body Sensors Applied in Pacemakers: A Survey  

E-print Network

a survey of the body sen- sors applied in pacemakers and recent advances in modern pacemaker systems. New of a patient. It is well known that implantable cardiac devices such as pacemakers are widely used nowadaysIEEE SENSORS JOURNAL, VOL. 12, NO. 6, JUNE 2012 1817 Body Sensors Applied in Pacemakers: A Survey

Wu, Mingshen

129

A short history on pacemakers.  

PubMed

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

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

2013-11-15

130

Interference between pacemakers/implantable cardioverter defibrillators and video capsule endoscopy.  

PubMed

Our Letter to the Editor, related to the article "Small bowel capsule endoscopy in patients with cardiac pacemakers and implantable cardioverter defibrillators: Outcome analysis using telemetry" by Cuschieri et al, comments on some small errors, that slipped into the authors discussions. The given informations concerning the pacemaker- and implantable cardioverter defibrillators modes were inaccurate and differ between the text and the table. Moreover, as 8 of 20 patient's pacemakers were programmed to VOO or DOO ("interference mode") and one patient was not monitored by telemetry during capsule endoscopy, 9 of 20 patients (45%) lack the informations of possible interference between capsule endoscopy their implanted device. Another objection refers to the interpretation of an electrocardiogram (figure 1, trace B) presented: in contrast to the author's opinion the marked spike should be interpreted as an artefact and not as "undersensing of a fibrillatory wave". Finally, three comments to cited reviews were not complete respectively not quoted correctly. PMID:23596547

Bandorski, Dirk; Gehron, Johannes; Höltgen, Reinhard

2013-04-16

131

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; )

2006-09-22

132

Computer-aided detection of pacemaker system problems  

Microsoft Academic Search

Cardiac pacemakers have grown markedly in longevity, reliability, efficacy, and flexibility with the impact of advancing electronics technology. Follow-up of complex dual-chamber pacemakers involves measurement and observations that can be facilitated by computer assistance beyond the realm of straightforward data management. New techniques include the direct acquisition of data and digitized waveforms from measurement instruments, requiring less user intervention and

Alan D. Bernstein; Victor Parsonnet

1983-01-01

133

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

134

Pacemakers, defibrillators, and direct current cardioversion.  

PubMed

Technology for pacemakers and automatic implantable defibrillators continues to evolve. Emphasis is placed not only on preventing cardiac death, but also on improving symptoms and quality of life. The basic antibradycardia function of pacemakers is complemented by highly sophisticated rate-responsive capabilities. The search for the perfect physiologic sensor has not ended; potential limitations of the systems currently available are considered in this review. Reports on outcome with pacing in different populations are also discussed. There have been two important advances in automatic implantable defibrillators. One is the introduction of the third generation defibrillator in clinical investigation. A tiered therapy (including antitachycardia pacing, cardioversion, and defibrillation) can now be programmed in the same device, with the protection of back-up antibradycardia pacing. The other remarkable innovation is the expanding use of nonthoracotomy techniques for implantable cardioverter-defibrillator placement. This approach permits the avoidance of a subcutaneous patch electrode in some cases, the system being entirely transvenous. Finally, recent insights on external cardioversion for atrial arrhythmias are briefly reviewed. PMID:10148086

Sgarbossa, E B; Black, I W; Maloney, J D

1993-01-01

135

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

Code of Federal Regulations, 2012 CFR

...prescribed exercise, cardiac risk factor...individual patient that includes...intensive cardiac rehabilitation, based on patient-centered...measures of exercise performance...Physician-prescribed exercise each day cardiac rehabilitation...tailored to the patients'...

2012-10-01

136

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

Code of Federal Regulations, 2011 CFR

...prescribed exercise, cardiac risk factor...individual patient that includes...intensive cardiac rehabilitation, based on patient-centered...measures of exercise performance...Physician-prescribed exercise each day cardiac rehabilitation...tailored to the patients'...

2011-10-01

137

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

Code of Federal Regulations, 2014 CFR

...prescribed exercise, cardiac risk factor...individual patient that includes...intensive cardiac rehabilitation, based on patient-centered...measures of exercise performance...Physician-prescribed exercise each day cardiac rehabilitation...tailored to the patients'...

2014-10-01

138

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

Code of Federal Regulations, 2010 CFR

...prescribed exercise, cardiac risk factor...individual patient that includes...intensive cardiac rehabilitation, based on patient-centered...measures of exercise performance...Physician-prescribed exercise each day cardiac rehabilitation...tailored to the patients'...

2010-10-01

139

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

Code of Federal Regulations, 2013 CFR

...prescribed exercise, cardiac risk factor...individual patient that includes...intensive cardiac rehabilitation, based on patient-centered...measures of exercise performance...Physician-prescribed exercise each day cardiac rehabilitation...tailored to the patients'...

2013-10-01

140

Effects of Lifestyle Modification Programs on Cardiac Risk Factors  

PubMed Central

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

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

2014-01-01

141

Effects of lifestyle modification programs on cardiac risk factors.  

PubMed

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

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

2014-01-01

142

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

143

Pacemaker insertion.  

PubMed

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

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

2015-03-01

144

Pacemaker insertion  

PubMed Central

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

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

2015-01-01

145

Recent Advances in Pacemaker Lead Technology  

Microsoft Academic Search

The cardiac pacemaker lead is a relatively fragile cable of insulated conductor wire implanted into the hostile environment of the human body. In comparison with the marked advances in pulse generator and sensor technology, concomitant advances in pacing leads have occurred slowly. This chapter will address recent engineering advances and clinical application of modern lead design.

Harry G. Mond

1999-01-01

146

Factors influencing enrollment in a cardiac rehabilitation exercise program.  

PubMed

In order to encourage enrollment in cardiac rehabilitation exercise programs, it is essential to understand the perceptions of both enrollers and non-enrollers. Factors influencing enrollment in a cardiac rehabilitation exercise program in a northern centre in Canada servicing a large rural area were examined. Letters of invitation to participate in the program were sent to 30 cardiac patients who had enrolled in the program as well as to 30 patients who had met medical clearance criteria and were eligible to participate but who had not enrolled. Responses were obtained from 20 enrollers and 9 non-enrollers. Participants completed a questionnaire developed by the investigators and then took part in a semi-structured interview. Both quantitative and qualitative data revealed physician recommendation as an influential factor for enrollment in the cardiac rehabilitation exercise program. Encouragement from family and friends and access to transportation also emerged as important factors for enrollers. The results of the study may assist health care professionals to increase enrollment in cardiac rehabilitation programs through education and provision of encouragement by appropriate individuals. PMID:12703100

Jones, Lee W; Farrell, Jocelyn M; Jamieson, John; Dorsch, Kim D

2003-01-01

147

Recent Advances of Sensors for Pacemakers Wei Vivien Shi1  

E-print Network

effectively prevent the sudden death of patients. It is known that implantable cardiac devices is the diagnosis of cardiac abnormalities via a pacemaker. This is because serious but infrequently occurring some consequence of a physiological change during exercise or facing emotional changes (temperature

Wu, Mingshen

148

Removal of infected pacemaker lead through sternotomy without cardiopulmonary bypass  

Microsoft Academic Search

A 66-year-old man, who had undergone DDD pacemaker implantation for complete A-V block two years ago, was admitted because\\u000a of endocarditis with septicemia and renal failure. His blood culture revealed Staphylococcus aureus. We tried to remove the\\u000a infected cardiac pacemaker lead. But we failed to remove the atrial lead because it was strongly adhered with the right atrial\\u000a appendage. Antibiotic

Yasushi Matsumoto; Katsushi Akemoto; Teruaki Ushijima; Kengo Kawakami; Takeshi Ueyama; Hisao Sasaki

1998-01-01

149

Pacemakers and Implantable Cardioverter Defibrillators in the Elderly  

Microsoft Academic Search

\\u000a Permanent pacemakers, implantable cardioverter defibrillators (ICDs) and cardiac resynchronization (CRT) devices are commonly\\u000a used in the management of cardiovascular disease. Sick sinus syndrome and atrio-ventricular block are the two most common\\u000a indications for permanent pacemaker implantation, representing more than 90% of the cases, and are both strongly associated\\u000a with increasing age. Understanding the cardiovascular physiology among elderly patients is critical

Luciana Armaganijan; Jeff S. Healey

150

MRI-conditional pacemakers: current perspectives  

PubMed Central

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

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

2014-01-01

151

Cardiac Rehabilitation  

MedlinePLUS

... from the NHLBI on Twitter. What Is Cardiac Rehabilitation? Cardiac rehabilitation (rehab) is a medically supervised program ... be designed to meet your needs. The Cardiac Rehabilitation Team Cardiac rehab involves a long-term commitment ...

152

Pacemaker-mediated angina.  

PubMed

Angina is a clinical syndrome characterized by discomfort in the chest, jaw, shoulder, back or arm. It is typically aggravated by exertion or emotional stress and relieved by nitroglycerin. Atherosclerotic coronary artery disease is the most common cause of angina. Dual-chamber pacemakers track the atrial electrical activity by pacing the ventricle. The present article reports the first case in the literature involving pacemaker-mediated angina. A 78-year-old man complained of chest pain shortly after the placement of a permanent dual-chamber pacemaker and experienced immediate relief of his pain after the pacemaker mode was switched from tracking the atrium and pacing the ventricle to sensing and pacing the ventricle. The pain was identified as angina pectoris. The comprehensive history-taking performed before pacemaker placement helped to quickly identify the cause of the patient's pain. PMID:24294035

Ibrahim, Morhaf; Hasan, Reham

2013-01-01

153

Continuous quality improvement program and major morbidity after cardiac surgery.  

PubMed

The aim of this study was to investigate how a continuous quality improvement (CQI) program affected major morbidity and postoperative outcomes after cardiac surgery. Patients were divided into 2 groups: those who underwent surgery (coronary artery bypass grafting, isolated valve surgery, or coronary artery bypass grafting and valve surgery) after the establishment of a CQI program (from January 2005 to December 2006, n = 922) and those who underwent surgery beforehand (from January 2002 to December 2003, n = 1,289). Patients who had surgery in 2004, when the system and processes were reengineered, were not included in the analysis. Outcomes compared between the 2 groups included (1) acute renal failure, (2) stroke, (3) sepsis, (4) hemorrhage-related reexploration, (5) cardiac tamponade, (6) mediastinitis, and (7) prolonged length of stay. Logistic regression analysis and propensity score adjustment were used to adjust for imbalances in the patients' preoperative characteristics. After propensity score adjustment, CQI was found to decrease the rate of sepsis (odds ratio [OR] 0.5, 95% confidence interval [CI] 0.3 to 0.9, p = 0.02) and cardiac tamponade (OR 0.2, 95% CI 0.04 to 0.8, p = 0.02) but to only marginally decrease the rate of acute renal failure (OR 0.7, 95% CI 0.5 to 1.0, p = 0.07). CQI did not emerge as an independent risk factor for hemorrhage-related reexploration, prolonged length of stay, mediastinitis, or stroke in either multivariate logistic regression analysis or propensity score adjustment. In conclusion, the systematic implementation of a CQI program and the application of multidisciplinary protocols decrease sepsis and cardiac tamponade after cardiac surgery. PMID:18774005

Stamou, Sotiris C; Camp, Sara L; Reames, Mark K; Skipper, Eric; Stiegel, Robert M; Nussbaum, Marcy; Geller, Rachel; Robicsek, Francis; Lobdell, Kevin W

2008-09-15

154

Electromagnetic Interference on Pacemakers  

PubMed Central

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

Erdogan, Okan

2002-01-01

155

Heart pacemaker - discharge  

MedlinePLUS

... interfere with your pacemaker. But some with strong magnetic fields may. Always ask your health care provider ... and high-voltage power lines Products that use magnetic therapy, such as some mattresses, pillows, and massagers ...

156

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

157

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

PubMed Central

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

2014-01-01

158

Subacute Right Ventricle Perforation by Pacemaker Lead Presenting with Left Hemothorax and Shock  

PubMed Central

Cardiac perforation by pacemaker is a rare but potentially fatal complication. Acute perforations occurring within twenty-four hours of insertion of pacemaker can lead to hemopericardium, cardiac tamponade, and death. Hemothorax occurring as an acute complication of pacemaker insertion is reported but extremely rare. Previously, hemothorax and shock as a subacute complication following pacemaker insertion have not been reported. We report the case of an 85-year-old patient who presented with shock from hemothorax caused by pacemaker perforation, two weeks after insertion. Device interrogation showed normal function. Chest X-ray and echocardiogram missed lead dislocation and the diagnosis was made on computed tomogram (CT) of the chest. Following surgical repair, a new ventricular pacemaker was placed transvenously in the right ventricular septum. This case illustrates that CT scan of the chest should be performed in all patients in whom cardiac perforation by pacemaker is suspected but not diagnosed on chest X-ray and echocardiogram. Normal functioning of pacemaker on device interrogation does not exclude perforation.

Nichols, Julianne; Berger, Natalie; Joseph, Praveen; Datta, Debapriya

2015-01-01

159

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

PubMed

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

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

2015-03-01

160

Effects of a comprehensive cardiac rehabilitation program in patients with coronary heart disease in Korea.  

PubMed

The purpose of this study was to develop a comprehensive cardiac rehabilitation program that considered patients' learning needs and cultural context, and to identify the impact of this program on patients with coronary heart disease in Korea. We employed a quasi-experimental design to evaluate the effects of the developed program in 61 patients with coronary heart disease. The experimental group received education, counseling, educational materials, and telephone follow-ups by cardiac nurses for six months. Results showed that participants of the program exhibited reduced body mass index and waist circumference as well as improved left ventricular diastolic function and cardiac disease-related quality of life. There was no significant difference between the groups with the rate of recurring symptoms or cardiac events. This comprehensive cardiac rehabilitation program safely and effectively improved body composition, cardiac function, and quality of life in patients with coronary heart disease. PMID:25040805

Kim, So-Sun; Lee, Sunhee; Kim, GiYon; Kang, Seok-Min; Ahn, Jeong-Ah

2014-12-01

161

Should surgeons still be implanting pacemakers?  

PubMed

Cardiac pacing has undergone major changes in the areas of manpower, technology, and cost over the past 10 years. Arguments have been made to eliminate cardiac surgical involvement in pacing on the basis of these three areas of change: implantations are increasingly performed by nonsurgeons, surgeons have not kept up with the technologic advances in pacing, and consolidation of bradypacing resources is necessary during a time when reimbursement has declined significantly. This study examined two eras of pacing therapy at an institution where pacemaker implantation has always been performed by cardiothoracic surgeons. The purpose of the study was to critically analyze (1) the current role (if any) of cardiothoracic surgeons in delivery of pacemaker therapy and (2) the current results of cardiothoracic surgical involvement in pacemaker implantation. In 1,562 procedures performed between 1986 and 1992, the infection rate was 0.51% and the overall complication rate (both short-term and long-term) was 5.2%. During era 1 (1/1/86 to 6/30/89), 80% of implants were single-chamber and follow-up was incomplete and dependent in many instances on the referring cardiologist/internist. For the implantations performed in the second era (7/1/89 to 12/31/92) as part of an established Pacemaker Service, complete clinical and transtelephonic follow-up services were provided by this coordinated medical-surgical approach. During era 2, 53.9% of implants were dual-chamber (79% during 1992). Total and infectious complication rates remained low in era 2 despite this change in technology.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8147626

Ferguson, T B; Lindsay, B D; Boineau, J P

1994-03-01

162

Pacemaker dependent patients with device infection—a modified approach  

Microsoft Academic Search

A modified surgical concept for temporary cardiac pacing in pacemaker dependent patients requiring total removal of infected devices is presented. Proximal to the infected pocket a permanent bipolar pacing lead is placed transcutaneously into the ipsilateral subclavian or jugular vein. The lead is placed in the right ventricle and fixed into the skin using the suture sleeve. Pacing is established

Ardawan Julian Rastan; Nicolas Doll; Thomas Walther; Friedrich Wilhelm Mohr

163

Pacemaker dependent patients with device infection—a modified approach  

Microsoft Academic Search

A modified surgical concept for temporary cardiac pacing in pacemaker dependent patients requiring total removal of infected devices is presented. Proximal to the infected pocket a permanent bipolar pacing lead is placed transcutaneously into the ipsilateral subclavian or jugular vein. The lead is placed in the right ventricle and fixed into the skin using the suture sleeve. Pacing is established

Ardawan Julian Rastan; Nicolas Doll; Thomas Walther; Friedrich Wilhelm Mohr

2005-01-01

164

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

165

Biventricular pacemakers in patients with heart failure.  

PubMed

Patients with heart failure may benefit from implantation of a biventricular pacemaker. This article discusses the indications for biventricular pacemaker implantation and the assessment of patients with biventricular pacemakers. Biventricular pacemakers require more assessments than do traditional single- or dual-chamber pacemakers. PMID:25834005

Cooper, Karen Leslie

2015-04-01

166

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

PubMed

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

Ochasi, Aloysius; Clark, Peter

2014-04-11

167

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

PubMed Central

Aims There are limited and contradictory data on the effects of CRT with implantable cardioverter defibrillator (CRT-D) on mortality as compared with CRT with pacemaker (CRT-P). Methods and results We evaluated the long-term outcome of patients implanted with a CRT-D or CRT-P device in our high-volume single-centre experience. Data on all-cause mortality were derived from clinic visits and the Hungarian National Healthcare Fund Death Registry. Kaplan–Meier survival analyses and multivariate Cox regression models were used to evaluate all-cause mortality in patients with CRT-D vs. CRT-P, stratified by the aetiology of cardiomyopathy. From 2000 to 2011, 1122 CRT devices, 693 CRT-P (LVEF 28.2?±?7.4%) and 429 CRT-D (LVEF 27.6?±?6.4%), were implanted at our centre. During the median follow-up of 28 months, 379 patients died from any cause, 250 patients (36%) with an implanted CRT-P and 129 patients (30%) with an implanted CRT-D. There was no evidence of mortality benefit in patients implanted with a CRT-D compared with a CRT-P in the total cohort [hazard ratio (HR) 0.98, 95% confidence interval (CI) 0.73–1.32, P?=?0.884]. In patients with ischaemic cardiomyopathy, CRT-D treatment was associated with a significant 30% risk reduction in all-cause mortality compared with an implanted CRT-P (HR 0.70, 95% CI 0.51–0.97, P?=?0.03). In non-ischaemic patients, there was no mortality benefit of CRT-D over CRT-P (HR 0.98, 95% CI 0.73–1.32, P?=?0.894, interaction P-value?=?0.15). Conclusions In heart failure patients with ischaemic cardiomyopathy, CRT-D was associated with a mortality benefit compared with CRT-P, but no benefit of CRT-D over CRT-P in mortality was observed in non-ischaemic cardiomyopathy. PMID:25379962

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

2014-01-01

168

21 CFR 870.3670 - Pacemaker charger.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Pacemaker charger. 870.3670 Section 870.3670...Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker charger is a device used...

2014-04-01

169

21 CFR 870.3670 - Pacemaker charger.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Pacemaker charger. 870.3670 Section 870.3670...Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker charger is a device used...

2011-04-01

170

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

171

21 CFR 870.3670 - Pacemaker charger.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Pacemaker charger. 870.3670 Section 870.3670...Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker charger is a device used...

2012-04-01

172

21 CFR 870.3700 - Pacemaker programmers.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Pacemaker programmers. 870.3700 Section 870...Cardiovascular Prosthetic Devices § 870.3700 Pacemaker programmers. (a) Identification. A pacemaker programmer is a device used to...

2011-04-01

173

Evaluation of a New Cardiac Pacemaker  

ClinicalTrials.gov

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

2013-06-25

174

EMOTION AND CARDIAC TECHNOLOGY: AN INTERPRETIVE STUDY  

Microsoft Academic Search

This paper presents a frequently overlooked aspect of advanced technological care - that of the human dimension and emotions. Emotionality is defined as the emotional ways that a client experiences their embodied experience as a recipient of a cardiac pacemaker. One individual' s story from a larger interpretive study of clients who received pacemakers is presented and interpreted. Kev' s

Carole Anderson; Wendy Moyle; Margaret McAllister

175

Electrosurgery-induced ventricular fibrillation during pacemaker replacement — a unique mechanism  

Microsoft Academic Search

Arrhythmias and pacemaker malfunction are known to occur from the use of an electrosurgical device. The present case report\\u000a describes a patient with sick sinus syndrome who experienced ventricular fibrillation while undergoing surgery. During replacement\\u000a of his non-functioning cardiac pacemaker under general anesthesia, electrosurgery was used to ensure hemostasis. Electric\\u000a current may have stimulated myocardial leads present in the surrounding

Anil Aggarwal; Neil E. Farber; G. S. Kotter; Mohammed S. Dharnee

1996-01-01

176

Electrosurgery-induced ventricular fibrillation during pacemaker replacement--a unique mechanism.  

PubMed

Arrhythmias and pacemaker malfunction are known to occur from the use of an electrosurgical device. The present case report describes a patient with sick sinus syndrome who experienced ventricular fibrillation while undergoing surgery. During replacement of his non-functioning cardiac pacemaker under general anesthesia, electrosurgery was used to ensure hemostasis. Electric current may have stimulated myocardial leads present in the surrounding tissue, leading to ventricular fibrillation. The patient was resuscitated from the episode without any residual sequelae. Microshock and possible mechanisms that can lead to ventricular arrhythmias in patients with pacemakers during electrosurgery are discussed. PMID:8863115

Aggarwal, A; Farber, N E; Kotter, G S; Dhamee, M S

1996-07-01

177

Effects of a brief intervention on retention of patients in a cardiac rehabilitation program.  

PubMed

This intervention assessed the effects of a brief intervention on dropout rate in a cardiac rehabilitation program. One hundred thirty five patients were recruited from a cardiac rehabilitation program and randomized to either a control or intervention group. The intervention group participated in four sessions of motivational interviewing and stress management-relaxation in addition to standard cardiac rehabilitation. The control group underwent cardiac rehabilitation alone. Patients who completed the intervention completed an average of 30 sessions while those who dropped out of the intervention completed about six (p < 0.001). Anxiety and depression measured at baseline were the primary predictors of dropout. Patients in both the intervention and controls groups who completed cardiac rehabilitation improved the distance walked, quality of life and decreased anxiety. PMID:25150038

McGrady, Angele; Burkes, Robert; Badenhop, Dalynn; McGinnis, Ron

2014-12-01

178

[Changes in pacemakers and the wearers of pacemakers as a result of the use of different electromagnetic energy sources].  

PubMed

Over the past decade there have been considerable advances in cardiac electrostimulation technologies. However, there are still reports of electromagnetic interference with pacemakers and pacemaker patients. We have studied the effects of various electromagnetic sources (short-wave diathermy, electrosurgical knives, electrotherapy and radiofrequencies) on both humans and animals. The results of the studies were completely negative and, therefore, we are convinced that today's pacemakers are much more reliable and hence less subject to interference from external electromagnetic sources. We performed the following tests: (a) Short-wave diathermy: various electrode positions in pigs and 8 patients with pacemakers. (b) Electrosurgical knives: several tests on pigs with unipolar electrosurgical knife; 6 tests on humans during automatic defibrillator implantation using two-pole electrosurgical knives; 23 pacemaker patients underwent abdominal surgery (3 inguinal hernias, 12 gastric resections; 6 cholecystotomies, 2 aortic aneurysms-with two-pole electrosurgical knives). (c) Electrotherapy (TENS): on pigs. (d) Radiofrequency (RF) for transcatheter ablation-several tests on pigs. PMID:8022542

Vergassola, R; Borgioli, A; Chiodi, L; Rossi, D; Fazi, A; Lebrun, E; Vaccari, M

1994-01-01

179

Evolutionary innovations in cardiac pacing  

Microsoft Academic Search

Cardiac pacing has played a significant role in mitigating morbidity and mortality associated with bradyarrhythmias. Throughout the years, advances made in battery reliability, lead performance, and device portability have rapidly expanded the use of cardiac pacemakers in many different disease states. Despite the benefits, there has been growing awareness of the potential deleterious effects of long-term artificial electrical stimulation including

Alan Cheng; Larisa G. Tereshchenko

180

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

NASA Astrophysics Data System (ADS)

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

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

2007-03-01

181

How to start and sustain a successful pediatric cardiac intensive care program: A combined clinical and administrative strategy.  

PubMed

OBJECTIVE: To delineate key clinical and administrative factors in starting a pediatric cardiac intensive care program and to introduce a scorecard concept to measure excellence in such a new program. Methods: Review of current clinical research data in pediatric cardiac intensive care and administrative business concepts for their application to the pediatric cardiac intensive care program. RESULTS: Although clinical concepts in cardiac intensive care are useful as basic philosophical strategies at the bedside, administrative principles are essential in operational strategies vital to the success of such a program. Using both clinical and business administrative concepts, a balanced strategy can be formulated. CONCLUSIONS: Starting a pediatric cardiac intensive care program is a difficult endeavor. A combined clinical and administrative approach is needed in starting and sustaining excellence in a pediatric cardiac intensive care program. Monitoring excellence in such a program warrants application of a scorecard system. PMID:12780977

Chang, Anthony C.

2002-04-01

182

1978 Pacemaker Newspaper Awards: What Makes a Pacemaker?  

ERIC Educational Resources Information Center

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

Brasler, Wayne

1979-01-01

183

Cardiac arrhythmias during exercise testing in healthy men.  

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

184

VideoLab: Optogenetic Pacemaker  

NSDL National Science Digital Library

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

Aristides B. Arrenberg (University of California; University of Freiburg; Department of Physiology; Institute of Biology)

2010-11-12

185

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

186

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

PubMed Central

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

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

2014-01-01

187

Interference of apex locator, pulp tester and diathermy on pacemaker function  

PubMed Central

Aim: The purpose of this study was to evaluate the effects of three electronic apex locators (EAL), electric pulp tester (EPT) and diathermy on pacemaker function in vitro. Materials and Methods: Three EALs: Root ZX (J. Morita Co., Tustin, CA, U.S.A.), Propex (Dentsply), Mini Apex locator (SybronEndo, Anaheim, CA, USA), EPT (Parkell pulp vitality tester Farmingdale, NY, USA) and Diathermy (Neomed 250 B) were tested for any interference with one pacemaker (A medtronic kappa KVDD901-serial number: PLE734632S). Directly connecting the pacemaker lead with the EAL/EPT/diathermy operating on a flat bench top, the telemetry wand was held directly over the pacemaker to monitor the pacing pattern for a period of 30 s. Pacemaker activity was continuously recorded on the telemetric programmer and electro gram (EGM) readings examined for pacer inhibition, noise reversion or inappropriate pacemaker pulses. Results: All the three apex locators showed no pacing interference or background noise during its function or at rest. The EGM readings of EPT showed varying levels of background noise in between pacing however, this did not affect the normal pacing pattern and the pacing interval remained constant. EGM readings of diathermy showed an increase in the pacing interval (irregular pacing pattern) followed by complete inhibition of the pacing system. Conclusion: The tested EALs do not interfere with cardiac pacemaker function. The tested EPT showed varying levels of background noise but does not interfere with cardiac pacemaker function. Use of Diathermy interfered with the normal pacing, leading to complete inhibition of the pacing system. PMID:25657520

Sriman, Narayanan; Prabhakar, V.; Bhuvaneswaran, J.S.; Subha, N.

2015-01-01

188

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

PubMed

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

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

2014-12-18

189

Defibrillator/monitor/pacemakers.  

PubMed

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

2000-09-01

190

Mechanical, but not infective, pacemaker erosion may be successfully managed by re-implantation of pacemakers  

Microsoft Academic Search

OBJECTIVE--When a pacemaker box causes erosion it is usually removed and a new pacemaker implanted at a contralateral site. In this study when there was no evidence of systemic infection an attempt was made to clean and reimplant the same pacemaker in the same site. RESULTS--Over 10 years 62 patients had pacemaker reimplantation. In 18 patients the procedure was repeated

M. J. Griffith; J. P. Mounsey; R. S. Bexton; M. P. Holden

1994-01-01

191

What Are the Risks of Pacemaker Surgery?  

MedlinePLUS

... or nerve damage A collapsed lung A bad reaction to the medicine used during the procedure Talk with your doctor about the benefits and risks of pacemaker surgery. Rate This Content: Next >> February 28, 2012 Pacemakers Clinical ...

192

Devices That May Interfere with Pacemakers  

MedlinePLUS

... that uses high-frequency, high-intensity signals for physical therapy. These may bypass your pacemaker's noise protection and ... that uses high-frequency, high-intensity signals for physical therapy. These may bypass your pacemaker's noise protection and ...

193

21 CFR 870.3700 - Pacemaker programmers.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

194

Biological pacemaker created by fetal cardiomyocyte transplantation  

Microsoft Academic Search

Summary Background—The aim of this study was to investigate the feasibility of an alternative approach to electronic pacemaker by using spontaneously excitable cell grafts as a biological pacemaker in a large animal model of complete atrioventricular block.

Guosheng Lin; Jun Cai; Hong Jiang; Hui Shen; Xuejun Jiang; Qijing Yu; Jian Song

2005-01-01

195

Ventricular perforation by pacemaker lead repaired with two hemostatic devices  

PubMed Central

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

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

2014-01-01

196

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

PubMed Central

We are developing a self-contained cardiac pacemaker with a small, cylindrical shape (~3×20mm) that permits it to be implanted percutaneously into a fetus to treat complete heart block and consequent hydrops fetalis, which is otherwise fatal. The device uses off-the-shelf components including a rechargeable lithium cell and a highly efficient relaxation oscillator encapsulated in epoxy and glass. A corkscrew electrode made from activated iridium can be screwed into the myocardium, followed by release of the pacemaker and a short, flexible lead entirely within the chest of the fetus to avoid dislodgement from fetal movement. The feasibility of implanting the device percutaneously under ultrasonic imaging guidance was demonstrated in acute adult rabbit experiments. PMID:23367442

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

2015-01-01

197

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

198

Pacemaker-induced change in prosthetic valvular sounds.  

PubMed

Variable intensity and timing of valvular sounds were noted in two patients with permanent pacemakers and prosthetic valves. In the first patient, who had a mitral and a tricuspid prosthesis, valvular opening sounds became widely separated with a change from nodal to ventricular paced rhythm. In a second patient, who had a mitral prosthesis in sinus rhythm with first-degree atrioventricular block, a very quiet closing sound increased markedly in intensity with the onset of ventricular pacing. The mechanism for these changes is described using a technique which at brief intervals throughout the cardiac cycle permitted documentation of simultaneously recorded phonocardiogram, electrocardiogram, and pulse tracings with a visible image of the prosthesis. In the usual patient with a prosthetic valve auscultatory changes should arouse a suspicion of malfunction; however, in the relatively uncommon patient with a prosthesis and an artificial pacemaker, it should be recognized that auscultatory changes may well have a physiologic explanation. PMID:1261315

Brown, D F; Prescott, G

1976-04-01

199

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

PubMed

The cardiovascular diseases (CVD) are the principal reasons of morbidity and mortality in the world. The cardiac rehabilitation is a program of secondary prevention to complement the effects of the cardiological treatment with the participation of the patient in the control of their habits of life, as a way of promotion of its own cardiovascular health. The aim of the present study is to evaluate the long-term effects of a cardiac rehabilitation program on some parameters of corporal composition in patients that have attended or not, to the phase the III of the program. The study was performed in subjects that suffered a cardiovascular event and they were members of the Association of Cardiac Patients of Granada and Province. All the members were offered the possibility of forming a part of the study. Some parameters of body composition were measured and a nutritional evaluation was performed in all the subjects. The visceral and body fat and, which play a key role in the cardiovascular pathology, are lower in the patients attending to the cardiac rehabilitation program, revealing that are better predictors of the cardiovascular risk. Thanks to the nutritional advice received, an increase in healthy nutrients is observed and the subjects attending to the program feature major phase angle, indicating that they have a better state of hydration, together with a better integrity of the cell membranes and distribution of water between the compartments intra- and extracellular compartments. PMID:25433120

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

2014-01-01

200

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

PubMed

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

Mond, Harry G; Freitag, Gary

2014-12-01

201

Pacemaker stored electrograms: teaching us what is really going on in our patients.  

PubMed

Stored electrograms (EGMs), well-known diagnostic tools in implantable cardioverter defibrillators, have now been incorporated in pacemakers as well, thereby increasing their diagnostic capabilities. The clinician can detect and diagnose patient arrhythmias with EGMs and directly validate diagnostic data stored by the devices. The appropriateness of detection algorithms can also be judged. Initial experiences with pacemaker EGMs reveals their potential to detect and diagnose sensing or detection algorithm problems. These so-called "false-positive" EGMs help to optimize pacemaker programming. Date and time stamp can correlate an event to patient symptoms. Recent advances, like onset recordings and marker annotation, have further increased the effectiveness of stored EGMs. The use of patient-triggered magnet-stored EGMs facilitates diagnostic workups in symptomatic pacemaker patients and reveals nondevice related symptoms in a considerable number of cases. Stored EGMs in pacemakers will soon be a standard diagnostic tool that can illustrate what is really going on in our patients. PMID:12049378

Nowak, Bernd

2002-05-01

202

Utility of a Dedicated Pediatric Cardiac Anticoagulation Program: The Boston Children's Hospital Experience.  

PubMed

Congenital heart disease is the leading cause of stroke in children. Warfarin therapy can be difficult to manage safely in this population because of its narrow therapeutic index, multiple drug and dietary interactions, small patient size, high-risk cardiac indications, and lack of data to support anticoagulation recommendations. We sought to describe our institution's effort to develop a dedicated cardiac anticoagulation service to address the special needs of this population and to review the literature. In 2009, in response to Joint Commission National Patient Safety Goals for Anticoagulation, Boston Children's Hospital created a dedicated pediatric Cardiac Anticoagulation Monitoring Program (CAMP). The primary purpose was to provide centralized management of outpatient anticoagulation to cardiac patients, to serve as a disease-specific resource to families and providers, and to devise strategies to evolve clinical care with rapidly emerging trends in anticoagulation care. Over 5 years the CAMP Service, staffed by a primary pediatric cardiology attending, a full-time nurse practitioner, and administrative assistant with dedicated support from pharmacy and nutrition, has enrolled over 240 patients ranging in age from 5 months to 55 years. The most common indications include a prosthetic valve (34 %), Fontan prophylaxis (20 %), atrial arrhythmias (11 %), cardiomyopathy (10 %), Kawasaki disease (7 %), and a ventricular assist device (2 %). A patient-centered multi-disciplinary cardiac anticoagulation clinic was created in 2012. Overall program international normalized ratio (INR) time in therapeutic range (TTR) is favorable at 67 % (81 % with a 0.2 margin) and has improved steadily over 5 years. Pediatric-specific guidelines for VKOR1 and CYP2C9 pharmacogenomics testing, procedural bridging with enoxaparin, novel anticoagulant use, and quality metrics have been developed. Program satisfaction is rated highly among families and providers. A dedicated pediatric cardiac anticoagulation program offers a safe and effective strategy to standardize anticoagulation care for pediatric cardiology patients, is associated with high patient and provider satisfaction, and is capable of evolving care strategies with emerging trends in anticoagulation. PMID:25573076

Murray, Jenna M; Hellinger, Amy; Dionne, Roger; Brown, Loren; Galvin, Rosemary; Griggs, Suzanne; Mittler, Karen; Harney, Kathy; Manzi, Shannon; VanderPluym, Christina; Baker, Annette; O'Brien, Patricia; O'Connell, Cheryl; Almond, Christopher S

2015-04-01

203

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. PMID:23869306

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

2013-01-01

204

The in vivo assessment of mechanical loadings on pectoral pacemaker implants  

Microsoft Academic Search

Reduced sizes of implantable cardiac pacemakers and clinical advances have led to a higher feasibility of using such devices in younger patients including children. Increased structural demands deriving from reduced device size and more active recipients require detailed knowledge of in vivo mechanical conditions to ensure device reliability. Objective of this study was the proof of feasibility of a system

Michael Hamman de Vaal; James Neville; Jacques Scherman; Peter Zilla; Micah Litow; Thomas Franz

2010-01-01

205

Pacemaking Kisspeptin Neurons  

PubMed Central

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

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

2013-01-01

206

Preparation for pacemaker or implantable cardiac defibrillator implants in patients with high risk of thrombo-embolic events: oral anticoagulation or bridging with intravenous heparin? A prospective randomized trial  

PubMed Central

Aims Current guidelines recommend stopping oral anticoagulation (OAC) and starting heparin infusion before implanting/replacing a pacemaker/implantable cardioverter-defibrillator (ICD) in patients with high risk for thrombo-embolic events. The aim of this study was to demonstrate that the maintenance of OAC during device implantation/replacement is as safe as bridging to intravenous heparin and shortens in-hospital stay. Methods and results A cohort of 101 consecutive patients with high risk for embolic events and indication for implant/replacement of a pacemaker/ICD were randomized to two anticoagulant strategies: bridging from OAC to heparin infusion (n = 51) vs. maintenance of OAC to reach an INR = 2 ± 0.3 at the day of the procedure (n = 50). Haemorrhagic and thrombo-embolic complications were evaluated at discharge, 15 and 45 days after the procedure. A total of 4/51 patients (7.8%) from heparin group and 4/50 (8.0%) from the OAC group developed pocket haematoma following the implant (P = 1.00). One haematoma in each group required evacuation (1.9 vs. 2%, P = 1.00). No other haemorrhagic events or embolic complications developed during the follow-up. Duration of the hospital stay was longer in the heparin group [median of 5 (4–7) vs. 2 (1–4) days; P < 0.001]. Conclusion Implant of devices maintaining OAC is as safe as bridging to heparin infusion and allows a significant reduction of in-hospital stay. PMID:19487235

Tolosana, Jose M.; Berne, Paola; Mont, Lluis; Heras, Magda; Berruezo, Antonio; Monteagudo, Joan; Tamborero, David; Benito, Begoña; Brugada, Josep

2009-01-01

207

Angina Pectoris and Atherosclerotic Risk Factors in the Multisite Cardiac Lifestyle Intervention Program  

Microsoft Academic Search

Cardiovascular symptom relief is a major indicator for revascularization procedures. To ex- amine the effects of intensive lifestyle modification on symptom relief, we investigated changes in angina pectoris, coronary risk factors, quality of life, and lifestyle behaviors in patients with stable coronary artery disease enrolled in the multisite cardiac lifestyle intervention program, an ongoing health insurance-covered lifestyle intervention conducted at

Joanne Frattaroli; Gerdi Weidner; Terri A. Merritt-Worden; Steven Frenda; Dean Ornish

208

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

ERIC Educational Resources Information Center

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

Jenny, Ng Yuen Yee; Fai, Tam Sing

2001-01-01

209

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

210

Real-time cardiac monitors.  

PubMed

Real-time cardiac monitors (RTCMs) are portable computerized devices that use programmed algorithms to perform rapid, readily available online analysis and processing of electrocardiographic (ECG) data. RTCMs are primarily applied for long-term monitoring of ambulatory cardiac outpatients for the purpose of detecting transient abnormal ECG events. A wide variety of RTCM devices is available ranging from limited capacity intermittent recorders that store only selected ECG data, to 24-hour full-disclosure systems that provide ECG complex and to replay this data for subsequent review. Critics of RTCMs suggest that the best algorithms are imperfect and may lead to errors involving potentially lethal arrhythmias, while proponents argue that real-time cardiac monitoring is sufficiently reliable for clinical use. Available data suggest that the devices are safe and particularly with regard to detecting ventricular arrhythmias, clinically reliable. Currently available algorithms cannot analyze atrial fibrillation, pacemaker rhythms, isolated P-waves, junctional rhythms, and atrial ventricular blocks. The advantages and limitations of RTCMs are well described. Their use can be applied to provide satisfactory results in the diagnosis, prognosis, and therapeutic amangement of selected patients. PMID:2699435

Handelsman, H

1989-01-01

211

Advanced Imaging Applications to Cardiac Resynchronization Therapy  

E-print Network

Advanced Imaging Applications to Cardiac Resynchronization Therapy Justin D. Pearlman Professor pacemaker leads can be placed to improve cardiac output, avoiding areas of dead tissue, and achieving of Medicine and Radiology Director of Advanced CV Imaging Dartmouth 4pm, Wed, Jan. 31, 2007 Auditorium

Zanibbi, Richard

212

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

213

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

214

Cardiac pacing in infants and children.  

PubMed

Pacemakers have been implanted in pediatric patients since the late 1960s. Indications for cardiac pacing in infants and children have evolved to include controlling symptoms as well as providing a life-sustaining cardiac rhythm. Pacemakers have become smaller and able to perform more complex functions. Current pacemakers offer a variety of operation modes, which are chosen on the basis of the pacing indication or the potential hemodynamic benefit. Today's pacemakers have the ability to maintain AV synchrony, perform rate-responsive pacing, and sometimes prevent or treat tachyarrhythmias. Recent advances in pacing lead technology, such as steroid elution, have narrowed the gap between epicardial and endocardial leads in terms of chronic pacing thresholds and sensing characteristics. The choice of a permanent pacing system is determined by the patient's size, underlying arrhythmia, and the anatomic details of any structural heart disease. Selection of temporary pacing modalities depends on the urgency of initiating pacing and the anticipated duration of temporary pacing. The decision to implant a permanent pacemaker in a pediatric patient commits the patient to long-term follow-up of pacemaker function. Such follow-up is important to ensure adequate safety margins for pacing and sensing, anticipate the need for pacemaker replacement, screen for pacemaker malfunctions, and optimize programmable settings. Pediatric cardiac pacing has evolved into its own subspecialty over the past decade. As more infants with complex congenital heart disease are being successfully treated with surgical palliation and repair, the population of pediatric patients with permanent pacemakers is likely to increase. PMID:11174899

Sliz, N B; Johns, J A

2000-01-01

215

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

PubMed

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

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

2012-01-01

216

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

PubMed

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

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

2011-01-01

217

Implantable Cardiac Rhythm Device Batteries  

Microsoft Academic Search

Batteries used for implantable cardiac rhythm devices are described herein. Fully implanted cardiac rhythm devices, pacemakers,\\u000a and defibrillators treat patients with various cardiomyopathies. Each of these devices contains a battery that supplies all\\u000a of the energy for device functions. As devices were developed with increased longevity, more features and reduced size, batteries\\u000a were designed with considerably greater energy and power.

Michael J. Root

2008-01-01

218

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

219

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

220

Pacemaker interference by magnetic fields at power line frequencies.  

PubMed

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 human body conductivity models make numerical modeling a viable technique for examining any such interference. In this paper, an existing well-verified scalar-potential finite-difference frequency-domain code is modified to handle thin conducting wires embedded in the body. The effects of each wire can be included numerically by a simple modification to the existing code. Results are computed for two pacemaker lead insertion paths, terminating at either atrial or ventricular electrodes in the heart. Computations are performed for three orthogonal 60-Hz magnetic field orientations. Comparison with simplified estimates from Faraday's law applied directly to extracorporeal loops representing unipolar leads underscores problems associated with this simplified approach. Numerically estimated electromagnetic interference (EMI) levels under the worst case scenarios are about 40 microT for atrial electrodes, and 140 microT for ventricular electrodes. These methods could also be applied to studying EMI with other implanted devices such as cardiac defibrillators. PMID:11876290

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

2002-03-01

221

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

222

Automatic detection of cardiac contours on MR images using fuzzy logic and dynamic programming.  

PubMed Central

This paper deals with the use of fuzzy logic and dynamic programming in the detection of cardiac contours in MR Images. The definition of two parameters for each pixel allows the construction of the fuzzy set of the cardiac contour points. The first parameter takes into account the grey level, and the second the presence of an edge. A corresponding fuzzy matrix is derived from the initial image. Finally, a dynamic programming with graph searching is performed on this fuzzy matrix. The method has been tested on several MR images and the results of the contouring were validated by an expert in the domain. This preliminary work clearly demonstrates the interest of this method, although a formal evaluation has to be done. Images Fig. 1 Fig. 3 Fig. 5 PMID:9357671

Lalande, A.; Legrand, L.; Walker, P. M.; Jaulent, M. C.; Guy, F.; Cottin, Y.; Brunotte, F.

1997-01-01

223

Anesthetic implications for patients with rate-responsive pacemakers.  

PubMed

One hundred thousand adults and children in the United States receive pacemakers each year, of which 85% are rate-responsive pacemakers (RRPs). Recent advances in the fields of computer programming and computer chip technology have led to the myriad development of RRPs, which contain sensors that automatically adjust the pacing rate to match the physiologic changes that occur during physical exertion. Because patients with RRPs may experience heart rate changes in the operating room due to ''normal'' sensor function, anesthesiologists must be aware of the new developments in RRP sensor technology to properly manage these patients. Increases in respiratory rate and tidal volume as well as the use of electrocautery have been reported to accelerate the paced rate of pacemakers with minute ventilation sensors. Likewise, patient movement and saws that produce vibrations can accelerate the paced rate of patients with piezoelectric crystal sensors. This paper discusses the history of pacemaker development, reviews the currently used RRP sensors, and recommends procedures for the perioperative management of these patients. Knowledge of sensor type and factors that stimulate them will help the anesthesiologist understand the cause of these changes so that he will be able to manage clinically significant hemodynamic changes due to RRP sensor activation. PMID:16151557

Anand, Neil K; Maguire, David P

2005-09-01

224

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

225

MGH West Cardiac Wellness Program Optimizing Health and Enhancing Resiliency  

E-print Network

, supervised exercise program to become more physically active and meet your individual needs for daily-healthy diet, assist in weight management and improve glucose and cholesterol levels · A comprehensive stress and Mind Your Heart: A Mind Body Approach to Stress Management, Exercise and Nutrition for Heart Health

Mootha, Vamsi K.

226

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

227

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

228

Critical Role of Donor Tissue Expression of Programmed Death Ligand1 in Regulating Cardiac Allograft Rejection and Vasculopathy  

Microsoft Academic Search

Background—Allograft vasculopathy is a major limiting factor in the long-term success of cardiac transplantation. T cells play a critical role in initiation of cardiac allograft rejection and allograft vasculopathy. The negative T-cell costimulatory pathway PD-1:PDL1\\/PDL2 (programmed death-1:programmed death ligand-1\\/2) plays an important role in regulating alloimmune responses. We investigated the role of recipient versus donor PD-1 ligands in the pathogenesis

Jun Yang; Joyce Popoola; Shakila Khandwala; Nidyanandh Vadivel; Vijay Vanguri; Xueli Yuan; Shirine Dada; Indira Guleria; Chaorui Tian; M. Javeed Ansari; Tahiro Shin; Hideo Yagita; Miyuki Azuma; Mohamed H. Sayegh; Anil Chandraker

2009-01-01

229

21 CFR 870.3710 - Pacemaker repair or replacement material.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Pacemaker repair or replacement material. ...Prosthetic Devices § 870.3710 Pacemaker repair or replacement material. (a) Identification. A pacemaker repair or replacement material...

2014-04-01

230

Computational Model of Electrically Coupled, Intrinsically Distinct Pacemaker Neurons  

E-print Network

Computational Model of Electrically Coupled, Intrinsically Distinct Pacemaker Neurons Cristina Soto, and Farzan Nadim. Computational model of electrically coupled, intrinsically distinct pacemaker neurons. J understood. Inspired by the pacemaker group of the crustacean pyloric network, we developed

Nadim, Farzan

231

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

232

21 CFR 870.3620 - Pacemaker lead adaptor.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 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...

2012-04-01

233

21 CFR 870.3730 - Pacemaker service tools.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Pacemaker service tools. 870.3730 Section...Cardiovascular Prosthetic Devices § 870.3730 Pacemaker service tools. (a) Identification. Pacemaker service tools are devices such as...

2012-04-01

234

21 CFR 870.3690 - Pacemaker test magnet.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Pacemaker test magnet. 870.3690 Section 870...Cardiovascular Prosthetic Devices § 870.3690 Pacemaker test magnet. (a) Identification. A pacemaker test magnet is a device used to test...

2013-04-01

235

21 CFR 870.3690 - Pacemaker test magnet.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Pacemaker test magnet. 870.3690 Section 870...Cardiovascular Prosthetic Devices § 870.3690 Pacemaker test magnet. (a) Identification. A pacemaker test magnet is a device used to test...

2012-04-01

236

21 CFR 870.3710 - Pacemaker repair or replacement material.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Pacemaker repair or replacement material. ...Prosthetic Devices § 870.3710 Pacemaker repair or replacement material. (a) Identification. A pacemaker repair or replacement material...

2012-04-01

237

21 CFR 870.3630 - Pacemaker generator function analyzer.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

238

21 CFR 870.1750 - External programmable pacemaker pulse generator.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

239

21 CFR 870.3630 - Pacemaker generator function analyzer.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

240

21 CFR 870.1750 - External programmable pacemaker pulse generator.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

241

21 CFR 870.3630 - Pacemaker generator function analyzer.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

242

21 CFR 870.3640 - Indirect pacemaker generator function analyzer.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

243

21 CFR 870.1750 - External programmable pacemaker pulse generator.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

244

21 CFR 870.1750 - External programmable pacemaker pulse generator.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

245

21 CFR 870.1750 - External programmable pacemaker pulse generator.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

246

21 CFR 870.3600 - External pacemaker pulse generator.  

Code of Federal Regulations, 2013 CFR

...false External pacemaker pulse generator. 870.3600 Section 870...3600 External pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has a power supply and...

2013-04-01

247

21 CFR 870.3610 - Implantable pacemaker pulse generator.  

Code of Federal Regulations, 2010 CFR

...Implantable pacemaker pulse generator. 870.3610 Section 870...Implantable pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a power supply and...

2010-04-01

248

21 CFR 870.3600 - External pacemaker pulse generator.  

Code of Federal Regulations, 2011 CFR

...false External pacemaker pulse generator. 870.3600 Section 870...3600 External pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has a power supply and...

2011-04-01

249

21 CFR 870.3610 - Implantable pacemaker pulse generator.  

Code of Federal Regulations, 2012 CFR

...Implantable pacemaker pulse generator. 870.3610 Section 870...Implantable pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a power supply and...

2012-04-01

250

21 CFR 870.3600 - External pacemaker pulse generator.  

Code of Federal Regulations, 2012 CFR

...false External pacemaker pulse generator. 870.3600 Section 870...3600 External pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has a power supply and...

2012-04-01

251

21 CFR 870.3610 - Implantable pacemaker pulse generator.  

Code of Federal Regulations, 2014 CFR

...Implantable pacemaker pulse generator. 870.3610 Section 870...Implantable pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a power supply and...

2014-04-01

252

21 CFR 870.3610 - Implantable pacemaker pulse generator.  

Code of Federal Regulations, 2013 CFR

...Implantable pacemaker pulse generator. 870.3610 Section 870...Implantable pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a power supply and...

2013-04-01

253

21 CFR 870.3610 - Implantable pacemaker pulse generator.  

Code of Federal Regulations, 2011 CFR

...Implantable pacemaker pulse generator. 870.3610 Section 870...Implantable pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a power supply and...

2011-04-01

254

21 CFR 870.3600 - External pacemaker pulse generator.  

Code of Federal Regulations, 2014 CFR

...false External pacemaker pulse generator. 870.3600 Section 870...3600 External pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has a power supply and...

2014-04-01

255

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

256

Gene therapy to create biological pacemakers  

Microsoft Academic Search

Old age and a variety of cardiovascular disorders may disrupt normal sinus node function. Currently, this is successfully\\u000a treated with electronic pacemakers, which, however, leave room for improvement. During the past decade, different strategies\\u000a to initiate pacemaker function by gene therapy were developed. In the search for a biological pacemaker, various approaches\\u000a were explored, including ?2-adrenergic receptor overexpression, down regulation

Gerard J. J. Boink; Jurgen Seppen; Jacques M. T. de Bakker; Hanno L. Tan

2007-01-01

257

Gene Therapy to Create Biological Pacemakers  

Microsoft Academic Search

Old age and a variety of cardiovascular disorders may disrupt normal sinus node function. Currently, this is successfully\\u000a treated with electronic pacemakers, which, however, leave room for improvement. During the past decade, different strategies\\u000a to initiate pacemaker function by gene therapy were developed. In the search for a biological pacemaker, various approaches\\u000a were explored, including ?\\u000a 2-adrenergic receptor overexpression, down

Gerard J. J. Boink; Jurgen Seppen; Jacques M. T. Bakker; Hanno L. Tan

258

Gene therapy to create biological pacemakers.  

PubMed

Old age and a variety of cardiovascular disorders may disrupt normal sinus node function. Currently, this is successfully treated with electronic pacemakers, which, however, leave room for improvement. During the past decade, different strategies to initiate pacemaker function by gene therapy were developed. In the search for a biological pacemaker, various approaches were explored, including beta(2)-adrenergic receptor overexpression, down regulation of the inward rectifier current, and overexpression of the pacemaker current. The most recent advances include overexpression of bioengineered ion channels and genetically modified stem cells. This review considers the strengths and the weaknesses of the different approaches and discusses some of the different viral vectors currently used. PMID:17048028

Boink, Gerard J J; Seppen, Jurgen; de Bakker, Jacques M T; Tan, Hanno L

2007-02-01

259

21 CFR 870.3630 - Pacemaker generator function analyzer.  

Code of Federal Regulations, 2014 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...

2014-04-01

260

21 CFR 870.3720 - Pacemaker electrode function tester.  

Code of Federal Regulations, 2011 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3720 Pacemaker electrode function tester. (a) Identification. A pacemaker electrode...

2011-04-01

261

21 CFR 870.3720 - Pacemaker electrode function tester.  

Code of Federal Regulations, 2010 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3720 Pacemaker electrode function tester. (a) Identification. A pacemaker electrode...

2010-04-01

262

21 CFR 870.3710 - Pacemaker repair or replacement material.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

263

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

264

21 CFR 870.3730 - Pacemaker service tools.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

265

21 CFR 870.3600 - External pacemaker pulse generator.  

Code of Federal Regulations, 2010 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3600 External pacemaker pulse generator. (a) Identification. An external pacemaker...

2010-04-01

266

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

PubMed

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

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

2013-01-01

267

DDD/DDT pacemakers in the treatment of ventricular tachycardia.  

PubMed

The possibility of adapting multimode dual-chamber pacemakers for programmed and burst stimulation was explored in a group of patients with ventricular tachycardia. The potential usefulness and pitfalls of these pacemakers were exemplified in one patient, presented in detail. The implanted DDD pacemaker was programmed to an all-synchronous mode (DDT), permitting programmed ventricular stimulation through synchronization with chest wall stimulation provided by a standard external programmable stimulator. With the ventricular sensing refractory period shortened to 200 ms, both programmed electrical stimulation and burst pacing for termination of induced tachycardias were possible. When medications failed to offer protection against the patient's tachycardias, the ventricular sensing refractory period (and minimum stimulation interval) was increased to 300 ms, thereby permitting burst pacing at up to 200 beats/minute for termination of spontaneous episodes. After many trials to confirm the efficacy of such stimulation, and the lack of muscle potential triggering, the patient was discharged home with the pacemaker in the DDT mode. He was instructed to go to his local emergency room, and was equipped with a portable device to trigger his implanted unit. Subsequently, the patient had successful termination of several spontaneous episodes of ventricular tachycardia in an emergency room. Later, he began to experience palpitations during certain exercises, and it was found that the implanted unit was being triggered by pectoral myopotentials. The unit was therefore reprogrammed to decrease the sensitivity, and the patient was again discharged. The need for careful evaluation and close follow-up is emphasized to maximize the benefits and to minimize the very serious potential risks of this pacing mode. PMID:6200841

Fisher, J D; Furman, S; Kim, S G; Matos, J A; Waspe, L E

1984-03-01

268

Improvements of Heart Failure by Cardiac Resynchronization Therapy in Cardiac Sarcoidosis  

Microsoft Academic Search

In patients with cardiac sarcoidosis, progression of the disease may lead to end-stage heart failure that requires emergent mechanical homodynamic support or heart transplantation. This case was a 66-year-old female with cardiac sarcoidosis complicated with atrioventricular block and decompensated heart failure requiring a pacemaker implantation, but the treatment was in vain. Finally, cardiac resynchronization therapy (CRT) improved her heart functionandclinicalsymptoms.Inconclusion,CRTcouldimprovetheheartfunctioninthiscasecausedbythiskind

Chieh-Shou Su; Jin-Long Huang; Yu-Cheng Hsieh; Chih-Tai Ting; Shih-Ann Chen

2009-01-01

269

Complete heart block in an adult with corrected transposition of the great arteries treated with permanent pacemaker.  

PubMed Central

A 53-year-old patient with corrected transposition of the great arteries developed complete heart block with fainting episodes. After temporary pacing through the endocardium of the venous (anatomically left) ventricle, a permanent epicardial pacemaker was implanted. This case shows the progressive nature of the atrioventricular conduction disturbances, which are very common in association with this congenital cardiac anomaly. Images PMID:505354

Amikam, S; Lemer, J; Kishon, Y; Riss, E; Neufeld, H N

1979-01-01

270

Recent advances of sensors for pacemakers  

Microsoft Academic Search

In this paper, the recent advances of sensors incorporated in pacemakers are presented. Based on the functions and operations of modern pacemakers, a variety of sensors are described with their rationales, features and applications. Further improvements and future trend of body sensors are pointed out. The comparison of the sensors' features is performed.

Wei Vivien Shi; MengChu Zhou

2011-01-01

271

Incidence and risk factors of upper extremity deep vein lesions after permanent transvenous pacemaker implant: a 6-month follow-up prospective study.  

PubMed

The incidence of venous lesions after permanent pacemaker insertion is around 45%. However, this incidence has been based on retrospective studies in a small series; moreover, factors predicting the development of these venous injuries have not been clearly defined. The aim of this study was to identify the risk factors for higher incidence of upper extremity deep vein thrombosis after transvenous permanent pacemaker insertion. The study included 229 patients and the criteria were age above 12 years and first permanent transvenous pacemaker implant. Exclusion criteria were pulmonary embolism, lower or upper extremity deep venous thrombosis, previous use of central venous catheters, coagulation disturbances, and malignancy. Age, race, sex, underlying cardiac disease, functional class to heart failure, LVEF, venous access, number, material and caliber of the leads, and previous use of a transvenous temporary pacemaker were considered. Six months after the pacemaker was implanted, 202 patients were submitted to digital subtraction venography ipsilateral to pacemaker implant. The venographies were normal in 73 (36%) patients and abnormal in 129 (64%) patients. Patients with previous use of transvenous temporary leads (P = 0,0001, OR = 4,260, confidence limits = 2,133-8,465) and LVEF < or = 40% (P = 0,0378, OR = 3,437, confidence limits = 1,064-12,326), had higher incidence of venous lesions. Previous use of a temporary pacemaker and LVEF < or = 0.40 were considered independent risk factors to a higher incidence of venous stenosis or thrombosis 6 months after permanent pacemaker insertion. PMID:12380764

Da Costa, Sergio Sidney do Carmo; Scalabrini Neto, Augusto; Costa, Roberto; Caldas, José Guilherme; Martinelli Filho, Martino

2002-09-01

272

Scoring method for assessing rate adaptive pacemakers: application to two different activity sensors.  

PubMed

To optimize programming of rate adaptive pacemakers (RAPs), we explored a new mathematical method to assess the performance of RAPs during daily-life tests, using customized Windows-based software. By stepwise discriminant analysis and linear regression, this method allows calculation of the acceleration and deceleration capacity of pacemakers and their general behavior during effort and recovery phases. Twenty-three patients (10 females and 13 males; 68 +/- 8 years) with chronic atrial fibrillation and a slow ventricular response were evaluated. They randomly received an accelerometer-controlled VVIR Dash Intermedics pacemaker (10 patients) or a vibration piezoelectric-controlled VVIR Sensolog III Siemens pacemaker (13 patients). All patients underwent the same test protocol: 6 minutes walking, 1.5 minutes climbing stairs, 1.5 minutes descending stairs, and 0.5 minutes sit-ups. By definition, the pacemaker responsiveness slope was programmed so that the heart rate response of paced patients during the walking test corresponded best to that of healthy controls. The slope was left unchanged for the other tests. We considered four scores: an acceleration score (EA score), an effort rate score (ER score), a deceleration score (RD score), and a recovery rate score (RR score). Scores ranged from -10 (hypochronotropic behavior of the pacemaker) to +10 (hyperchronotropic behavior), based on daily-life tests of 15 healthy controls (7 females and 8 males, 65 +/- 9 years). A score of 0 represented exact concordance with healthy controls. During stair descent, the Sensolog III produced excessive acceleration (EA score = +2.9 +/- 1.1) compared to: (1) stair climbing (EA score = -4.0 +/- 1.9; P = 0.01, with the same pacemakers); and (2) the Dash (+1.8 +/- 1.9; P = 0.04) and healthy controls (P = 0.02). The sit-up tests revealed a hypochronotropic response of both pacemakers compared to healthy controls, with a larger difference for the Sensolog III (EA score = -2.0 +/- 5.8; P = 0.04; RD score = -6.8 +/- 3.8' P = 0.02). We conclude that activity-driven pacemakers can accommodate brief activities, except for isovolumetric exercise such as sit-ups. During daily activities, accelerometer-driven pacemakers seem to provide a heart rate resoibse closer to that of healthy controls. Our new mathematical analysis is a simple and reproducible method for evaluating and quantifying the efficacy of any sensor-driven pacemaker. PMID:9558681

Garrigue, S; Chaix, C; Gencel, L; Jaïs, P; Dartigues, J F; Haïssaguerre, M; Clémenty, J

1998-03-01

273

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

PubMed Central

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

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

2014-01-01

274

Managing pacemaker-related complications and malfunctions in the emergency department.  

PubMed

The use of implanted pacemaker devices is increasing worldwide, owing to technological advances, new indications, and an aging population. Despite greater experience in implantation and improved device sophistication, patients continue to face complications associated with hardware implantation and device malfunction. This review summarizes current indications for permanent pacing, reviews epidemiologic data relevant to implant complications, and describes a clinical approach to the patient with potential pacing malfunction. The electrocardiographic diagnosis of hyperkalemia and acute myocardial infarction in paced rhythms is also discussed. Potential sources of electromagnetic interference and special considerations pertaining to the cardiac resuscitation of patients with implanted cardiac devices are reviewed. Finally, a basic approach to implanted cardioverter-defibrillator devices (which often accompany pacemaker devices) is presented. PMID:25436255

Martindale, Jennifer; deSouza, S

2014-09-01

275

Cardiac Rehabilitation in Older Cardiac Patients  

Microsoft Academic Search

Cardiac rehabilitation services are comprehensive, long-term programs involving medical evaluation, prescribed exercise,\\u000a cardiac risk factor modification, education and counseling. These programs are designed to limit the physiologic and psychologic\\u000a effects of cardiac illness, reduce the risk for sudden death or reinfarction, control cardiac symptoms, stabilize or reverse\\u000a the atherosclerotic process, and enhance the psychosocial and vocational status of patients with

Philip A. Ades

276

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

PubMed Central

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

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

2014-01-01

277

Pacemakers charging using body energy.  

PubMed

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

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

2010-01-01

278

An ultra wideband propagation model for wireless cardiac monitoring devices  

Microsoft Academic Search

Wireless communication is an important technology to improve e-health applications such as remote cardiac monitoring. In modern telemedicine it is desirable that implant cardiac devices such as pacemakers can be interrogated and reprogrammed remotely. Such functions require a reliable wireless communication channel between the implant device and an external control unit. In order to increase the longevity of the implant

Raúl Chávez-Santiago; Ali Khaleghi; Ilangko Balasingham

2010-01-01

279

Alternative view on the mechanism of cardiac rhythmogenesis  

Microsoft Academic Search

Background: This article advances an hypothesis that there is duplication of the heart rhythmogenesis system.Methods and Results: The following article reviews available data and advances an hypothesis to suggest new ideas about the mechanisms of cardiac rhythm generation. The hypothesis is that along with the existence of an intracardiac pacemaker, the generator of cardiac rhythm exists in the central nervous

Vladimir M. Pokrovskii

2003-01-01

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

Cardiac pacing leads.  

PubMed

Many of the advances that have been seen in the last decade concerning the functionality, size, and longevity of cardiac pacemakers have been dependent upon concomitant advances in cardiac pacing leads. The most difficult component of a pacing lead to develop has been the insulator. There are many choices for physicians implanting pacing leads: active versus passive fixation, standard impedance versus high impedance and polyurethane versus silicone. The current state of affairs of cardiac pacing leads is quite good in that we have leads that have excellent electrical properties and appear to be more resistant to the hostile environment into which the lead is placed. In spite of this, the goal of a perfect lead remains elusive and there continues to be many challenges in lead design. PMID:10709688

Crossley, G H

2000-02-01

282

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

PubMed

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

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

2011-02-21

283

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

PubMed Central

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

Pastromas, Sokratis; Manolis, Antonis S

2014-01-01

284

Pacemaker  

MedlinePLUS

... the signal travels, it causes the heart to contract and pump blood. Each electrical signal normally begins ... two upper chambers, the atria (AY-tree-uh), contract. This contraction pumps blood into the heart's two ...

285

Management of recurrent pacemaker-related bacteraemia with small colony variant Staphylococcus aureus in a haemodialysis patient  

PubMed Central

A patient with chronic haemodialysis with a cardiac pacemaker was admitted for five episodes of bacteraemia with Staphylococcus during an 8-month period. The species identification was complicated since the morphological characters and biochemical reactions were unusual and differing. Molecular biological identification and typing methods revealed that the pathogens for all the episodes were the same strain of Staphylococcus aureus that had small colony variant characteristics. Continuous suppressive antibiotic treatment initiated after the last infection episode has been able to keep the patient free of bacteraemia relapse during the past 24 months without removing the pacemaker. PMID:21857872

Nielsen, Xiaohui Chen; Nielsen, Finn Thomsen; Kurtzhals, Jørgen A L; Moser, Claus; Boye, Kit; Christensen, Jens Jørgen; Johansen, Ulla Rydal; Westh, Henrik

2009-01-01

286

Effectiveness of implantation of a subcutaneous implantable cardioverter-defibrillator in a patient with complete heart block and a pacemaker.  

PubMed

The subcutaneous implantable cardioverter-defibrillator (S-ICD) represents an important alternative to traditional ICD therapy. The major limitation of this technology is the inability to provide pacing. Here, we present a case of a patient with complete heart block and a pacemaker who underwent placement of an S-ICD. Special considerations had to be taken with regards to evaluation and implantation of the S-ICD because of the pacemaker. In conclusion, implantation of an S-ICD can be done in patients with pacemaker effectively with appropriate electrocardiographic screening, device testing, and programming. PMID:25465940

Porterfield, Christopher; DiMarco, John P; Mason, Pamela K

2015-01-15

287

Update on arrhythmias and cardiac pacing 2013.  

PubMed

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

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

2014-04-01

288

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

PubMed

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

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

2013-12-01

289

Deactivation of Pacemakers and Implantable Cardioverter-Defibrillators  

PubMed Central

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

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

2013-01-01

290

Deactivation of pacemakers and implantable cardioverter-defibrillators.  

PubMed

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

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

2012-01-01

291

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

292

A molecular signature of tissues with pacemaker activity in the heart and upper urinary tract involves coexpressed hyperpolarization-activated cation and T-type Ca2+ channels  

PubMed Central

Renal pacemakers set the origin and frequency of the smooth muscle contractions that propel wastes from the kidney to the bladder. Although congenital defects impairing this peristalsis are a leading cause of pediatric renal failure, the mechanisms underlying renal pacemaker activity remain unknown. Using ratiometric optical mapping and video microscopy, we discovered that hyperpolarization-activated cation (HCN) channel block with the specific anatagonist ZD7288 (30 ?m; IC50) abolished the pacemaker depolarizations that initiate murine upper urinary tract peristalsis. Optical mapping and immunohistochemistry indicate that pacemaker potentials are generated by cells expressing HCN isoform-3, and that HCN3+ cells are coupled to definitive smooth muscle via gap junctions. Furthermore, we demonstrate that HCN3+ cells coexpress T-type Ca2+ (TTC) channels and that TTC channel inhibition with R(?)efonidipine or NNC55-0396 decreased contractile frequency in a dose-dependent manner. Collectively, these data demonstrate that HCN3+/TTC+ cells are the pacemakers that set the origin and rate of upper urinary tract peristalsis. These results reveal a conserved mechanism controlling autorhythmicity in 2 distinct muscle types, as HCN and TTC channels also mediate cardiac pacemaker activity. Moreover, these findings have translational applications, including the development of novel diagnostics to detect fetal urinary tract motility defects prior to renal damage.—Hurtado, R., Bub, G., Herzlinger, D. A molecular signature of tissues with pacemaker activity in the heart and upper urinary tract involves coexpressed hyperpolarization-activated cation and T-type Ca2+ channels. PMID:24189942

Hurtado, Romulo; Bub, Gil; Herzlinger, Doris

2014-01-01

293

Angina pectoris and atherosclerotic risk factors in the multisite cardiac lifestyle intervention program.  

PubMed

Cardiovascular symptom relief is a major indicator for revascularization procedures. To examine the effects of intensive lifestyle modification on symptom relief, we investigated changes in angina pectoris, coronary risk factors, quality of life, and lifestyle behaviors in patients with stable coronary artery disease enrolled in the multisite cardiac lifestyle intervention program, an ongoing health insurance-covered lifestyle intervention conducted at 22 sites in the united states. Patients with coronary artery disease (nonsmokers; 757 men, 395 women; mean age 61 years) were asked to make changes in diet (10% calories from fat, plant based), engage in moderate exercise (3 hours/week), and practice stress management (1 hour/day). At baseline, 108 patients (43% women) reported mild angina and 174 patients (37% women) reported limiting angina. By 12 weeks, 74% of these patients were angina free, and an additional 9% moved from limiting to mild angina. This improvement in angina was significant for patients with mild and limiting angina at baseline regardless of gender (p <0.01). Significant improvements in cardiac risk factors, quality of life, and lifestyle behaviors were observed, and patients with angina who became angina free by 12 weeks showed the greatest improvements in exercise capacity, depression, and health-related quality of life (p <0.05). In conclusion, the observed improvements in angina in patients making intensive lifestyle changes could drastically reduce their need for revascularization procedures. PMID:18359307

Frattaroli, Joanne; Weidner, Gerdi; Merritt-Worden, Terri A; Frenda, Steven; Ornish, Dean

2008-04-01

294

Optimization of atrio-ventricular delay in patients with dual-chamber pacemaker.  

PubMed

Development and advances in heart pacing over the last nearly half a century allowed to save numerous lives by providing pacing support in bradycardia and complete heart block. Nevertheless, long-term follow up of patients with implanted pacemaker showed unfavorable remodeling of the heart, both from hemodynamic as well as electrical standpoint. The optimal programmed pacemaker setting, apart from the optimal place for ventricular stimulation, is essential to obtain the best hemodynamic and the clinical after-effects of the stimulation of the heart and to minimize potential unfavorable effects. In patients with dual-chamber pacemaker (DDD) the correct function of the left ventricle of the heart depends mainly on the electric delays between the stimulated chambers. Atrio-ventricular delay (AVD) during dual-chamber pacing influences left ventricle contraction function through preload modulation. Improperly programmed AVD in the DDD pacemaker can have unfavorable hemodynamic results. Various methods have been developed during last few decades (right heart catheterization, ventriculography, peak endocardial acceleration, echocardiography, and impedance cardiography), however only echocardiography and reocardiography are currently in general use. There should be noticed too, that also the application of special algorithms present in modern pacemakers allowing for dynamic changes of the time of the delay represents certain alternative to individual AVD optimization. PMID:19931200

Klimczak, Artur; Chudzik, Micha?; Zieli?ska, Marzenna; Budzikowski, Adam S; Lewek, Joanna; Wranicz, Jerzy K

2010-06-11

295

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

EPA Science Inventory

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

296

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. PMID:23140449

2012-01-01

297

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. PMID:24179555

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

2013-01-01

298

21 CFR 870.3650 - Pacemaker polymeric mesh bag.  

Code of Federal Regulations, 2013 CFR

... MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. ...pacemaker pulse generator. The bag is designed to create a stable implant environment for the pulse generator. (b)...

2013-04-01

299

21 CFR 870.3650 - Pacemaker polymeric mesh bag.  

Code of Federal Regulations, 2011 CFR

... MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. ...pacemaker pulse generator. The bag is designed to create a stable implant environment for the pulse generator. (b)...

2011-04-01

300

21 CFR 870.3650 - Pacemaker polymeric mesh bag.  

Code of Federal Regulations, 2012 CFR

... MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. ...pacemaker pulse generator. The bag is designed to create a stable implant environment for the pulse generator. (b)...

2012-04-01

301

21 CFR 870.3690 - Pacemaker test magnet.  

Code of Federal Regulations, 2014 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3690 Pacemaker test magnet. (a) Identification. A pacemaker test magnet is a device used...

2014-04-01

302

21 CFR 870.3620 - Pacemaker lead adaptor.  

Code of Federal Regulations, 2014 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device...

2014-04-01

303

21 CFR 870.3620 - Pacemaker lead adaptor.  

Code of Federal Regulations, 2013 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device...

2013-04-01

304

21 CFR 870.3650 - Pacemaker polymeric mesh bag.  

Code of Federal Regulations, 2014 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is...

2014-04-01

305

21 CFR 870.3650 - Pacemaker polymeric mesh bag.  

Code of Federal Regulations, 2010 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is...

2010-04-01

306

21 CFR 870.3690 - Pacemaker test magnet.  

Code of Federal Regulations, 2010 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3690 Pacemaker test magnet. (a) Identification. A pacemaker test magnet is a device used...

2010-04-01

307

Optimal atrioventricular delay at rest and during exercise in patients with dual chamber pacemakers: a non-invasive assessment by continuous wave Doppler  

Microsoft Academic Search

The optimal atrioventricular delay at rest and during exercise was investigated in nine patients with heart block and implanted dual chamber pacemakers. All patients studied had normal left ventricular function and a normal sinus node rate response to exercise. Cardiac output was measured by continuous wave Doppler and was calculated as the product of stroke distance measured by Doppler at

D Mehta; S Gilmour; D E Ward; A J Camm

1989-01-01

308

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

PubMed

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

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

2011-10-01

309

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

PubMed

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

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

2015-04-15

310

Resonance Pacemakers in Excitable Media Tabitha Ruvarashe Chigwada,1  

E-print Network

Resonance Pacemakers in Excitable Media Tabitha Ruvarashe Chigwada,1 P. Parmananda,2,3 and Kenneth oscillatory region that serves as a pacemaker, emitting successive waves into the medium. In the Belousov adsorption of bromide (or bromine) is responsible for the spontaneous pacemakers at hetero- geneities

Showalter, Kenneth

311

background Na+ conductance in pacemaking activity is unproven,  

E-print Network

background Na+ conductance in pacemaking activity is unproven, only the hasty would suggest that it is unlikely. Arrested pacemaker cells have membrane potentials of -35mY: some outward current must flow the membranes of arrested pacemaker cells whereas vagal stimulation does7. In beat- ing hearts vagal stimulation

Apkarian, A. Vania

312

Autonomic control and innervation of the atrioventricular junctional pacemaker  

E-print Network

Autonomic control and innervation of the atrioventricular junctional pacemaker William J. Hucker junction may be- come the pacemaker of the heart. Unlike the well-characterized sinoatrial node (SAN), autonomic control of the AV junctional pacemaker has not been studied. OBJECTIVE The purpose of this study

313

How Genetic Algorithms Can Improve a Pacemaker Effciency  

E-print Network

How Genetic Algorithms Can Improve a Pacemaker Effciency Laurent Dumas Laboratoire Jacques In this paper, we propose the use of Genetic Algorithms as a tool for improving a pacemaker efficiency induced in the sinus node, the natural pacemaker, then propagates through the atria and reaches

Dumas, Laurent

314

Complications of Dual Chamber Pacemaker Implantation in the Elderly  

Microsoft Academic Search

Pacemakers are frequently implanted, yet accurate prospective data on implant complications are limited. Elderly patients may be at increased risk of implant complications and are increasingly being referred for pacemaker implantation. The purpose of the present analysis was to define the incidence and possible predictors of serious complications of dual chamber permanent pacemaker implantation in the elderly. Therefore, we sought

Mark S. Link; N. A. Mark Estes III; John J. Griffin; Paul J. Wang; James D. Maloney; James B. Kirchhoffer; Gary F. Mitchell; John Orav; Lee Goldman; Gervasio A. Lamas

1998-01-01

315

Extraction of pacemaker and implantable cardioverter defibrillator leads.  

PubMed

The common reasons for removal of pacing and defibrillator leads are infection, malfunction, or design defects such as fracture of J wires in Teletronics Accufix leads (Telectronics Pacing, Englewood, CO), which impose considerable risk for cardiac morbidity and mortality. Chronically implanted leads are fixed to the myocardium by fibrous tissue. Fibrous scar tissue may also encase the lead along its course. Furthermore, fragility of the lead and its tendency to break when extraction force is applied to overcome resistance imparted by the scar tissue add to the challenge of lead extraction. Thus, the extraction of chronically implanted leads is an important issue. Until a few years ago, the only methods available for the removal of chronically implanted leads were traction on the proximal segment of the lead and cardiac surgery. New techniques were developed to extract the leads by a transvenous approach using locking stylets, sheaths, snares, and retrieval baskets. Lead extraction using intravascular countertraction methods has since evolved as a specialty of its own. Progress has also been made in developing other system, such as Excimer laser energy for lead extraction. In this article, we discuss principles, techniques, and experience with these methods of extraction of chronic pacemaker and defibrillator leads. PMID:9932207

Kantharia, B K; Kutalek, S P

1999-01-01

316

Myopotential inhibition of unipolar lithium pacemakers.  

PubMed

The effect of isometric upper extremity exercise on pacemaker function was evaluated in 27 patients who remained pacemaker-dependent during testing. Inhibition was demonstrated in eight (31 percent) of which five were symptomatic. Based on design of the sensing amplifier and return to an all-metal housing in the unipolar lithium pulse generators, myopotential inhibition is being recognized as one cause of symptomatic pacemaker inhibition that is more common than generally appreciated. A method of evaluation and management options for symptomatic patients are discussed. Routine testing of all patients should be performed at the time of a regular office evaluation. If one model pulse generator appears to be particularly prone to myopotential inhibition, this knowledge should be considered in the choice of future pacing systems. PMID:7116965

Levine, P A; Caplan, C H; Klein, M D; Brodsky, S J; Ryan, T J

1982-10-01

317

Autonomic cardiac innervation  

PubMed Central

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

Hasan, Wohaib

2013-01-01

318

A generalized model of active media with a set of interacting pacemakers: Application to the heart beat analysis  

E-print Network

We propose a quite general model of active media by consideration of the interaction between pacemakers via their phase response curves. This model describes a network of pulse oscillators coupled by their response to the internal depolarization of mutual stimulations. First, a macroscopic level corresponding to an arbitrary large number of oscillatory elements coupled globally is considered. As a specific and important case of the proposed model, the bidirectional interaction of two cardiac nodes is described. This case is generalized by means of an additional pacemaker, which can be expounded as an external stimulater. The behavior of such a system is analyzed. Second, the microscopic level corresponding to the representation of cardiac nodes by one-- and two--dimensional lattices of pulse oscillators coupled via the nearest neighbors is described. The model is a universal one in the sense that on its basis one can easily construct discrete distributed media of active elements, which interact via phase response curves.

Sergei Rybalko; Ekaterina Zhuchkova

2006-03-15

319

[Complications of permanent cardiac pacing].  

PubMed

The implantation of a pacemaker is an everyday medical procedure. New indications are under evaluation. However, it should be recalled that this is a surgical intervention with implantation of a prosthesis with possible complications. This should, therefore, be a considered decision. There are early complications which occur in the first 6 weeks after implantation. Their incidence is underestimated (up to 7%) as is their seriousness. There are late complications. Some are responsible for pacemaker dysfunction, the risk of which is proportional to the dependence of the patient on permanent cardiac pacing. The migration of a pacing catheter or the fracture of an Accufix catheter expose the patient to much greater risk. Venous complications are overlooked as they are usually asymptomatic. The superior vena cava syndrome is, however, a serious complication of cardiac pacing. Two recent studies (MOST and DAVID) underline the deleterious haemodynamic effects of unnecessary right ventricular pacing. This right ventricular pacing may have a pro-arrhythmic effect on the ventricles and be responsible for sudden death. It may also cause atrial arrhythmia even if atrio-ventricular synchronisation is preserved. Infectious complications are also under-reported, partially because of the difficulty of diagnosis. They may be life-threatening and require extraction of the implanted material. In conclusion, it is wrong to think that even if a patient does not benefit from his implanted device this cannot have deleterious consequences. Pacemakers should be adjusted especially to avoid inappropriate right ventricular stimulation. PMID:15272521

Klug, D; Marquié, C; Lacroix, D; Kacet, S

2003-12-01

320

Mechanical Loadings on Pectoral Pacemaker Implants: Correlation of In-line and Transverse Force of the Pectoralis major  

Microsoft Academic Search

Recently we presented a method for the assessment of in vivo forces on pectoral device implants motivated from technological and clinical advancements toward smaller implantable cardiac\\u000a pacemakers and the altered structural demands arising from the reduced device size. Objective of this study was the investigation\\u000a of the intra-species proportionality of in-line force and transverse reaction force of the Pectoralis major

M. H. de Vaal; J. Neville; J. Scherman; P. Zilla; M. Litow; T. Franz

2010-01-01

321

Rationale and design of the cardiac hospitalization atherosclerosis management program at the University of California Los Angeles  

Microsoft Academic Search

Despite clear and consistent clinical-trial evidence that secondary-prevention medical therapies reduce mortality in patients with established coronary artery disease, these therapies are underutilized in patients receiving conventional care. To address this issue, a Cardiac Hospitalization Atherosclerosis Management Program (CHAMP) focused on initiation of aspirin, cholesterol-lowering medication (3-hydroxy-3-methylglutaryl-coenzyme A [HMG-CoA] reductase inhibitor titrated to achieve low-density lipoprotein [LDL] cholesterol

Gregg C Fonarow; Anna Gawlinski

2000-01-01

322

Sinus node dysfunction requiring permanent pacemaker implantation in a young adult with klinefelter syndrome.  

PubMed

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

Karagöz, Ahmet; Dikba?, O?uz; Teker, Erhan; Vural, Asl?; Günayd?n, Zeki Yüksel; Bekta?, Osman

2015-01-01

323

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

PubMed Central

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

Karagöz, Ahmet; Dikba?, O?uz; Teker, Erhan; Vural, Asl?; Günayd?n, Zeki Yüksel; Bekta?, Osman

2015-01-01

324

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. PMID:21677184

Li, Jie; Baccei, Mark L.

2011-01-01

325

Gene therapy in cardiac arrhythmias.  

PubMed

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

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

2006-01-01

326

Development and Evaluation of a Course Module on Cardiac Signal Procesing  

Microsoft Academic Search

We report our experiences with a new course module covering cardiac signal processing in an instrumentation course intended for advanced undergraduates. The module covers the state of the art in analog, digital and mixed signal processing methods with a focus on the latest design approaches. This includes low-power Digital Signal Processing (DSP) and switch\\/capacitor methods in cardiac pacemakers and advanced

Alan V. Sahakian; Eric Y. Yang

2002-01-01

327

Endogenous circadian rhythm in an index of cardiac vulnerability independent of changes in behavior  

E-print Network

Endogenous circadian rhythm in an index of cardiac vulnerability independent of changes in behavior, influences from the endogenous circadian pacemaker independent from behaviors may also affect cardiac control features of the healthy human heartbeat have an endogenous circadian rhythm that brings the features closer

Stanley, H. Eugene

328

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

329

Measuring pacemaker dose: a clinical perspective.  

PubMed

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

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

2012-01-01

330

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

PubMed Central

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

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

2013-01-01

331

Evolutionary innovations in cardiac pacing.  

PubMed

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

Cheng, Alan; Tereshchenko, Larisa G

2011-01-01

332

The Impacts of Cardiac Rehabilitation Program on Echocardiographic Parameters in Coronary Artery Disease Patients with Left Ventricular Dysfunction  

PubMed Central

Introduction. The accurate impact of exercise on coronary artery disease (CAD) patients with left ventricular dysfunction is still debatable. We studied the effects of cardiac rehabilitation (CR) on echocardiography parameters in CAD patients with ventricular dysfunction. Methods. Patients with CAD who had ventricular dysfunction were included into an exercise-based rehabilitation program and received rehabilitation for eight weeks. All subjects underwent echocardiography before and at the end of the rehabilitation program. The echocardiography parameters, including left ventricular ejection fraction (LVEF), LV end-diastolic (LVEDD) and end-systolic diameters (LVESD), and peak exercise capacity measured in metabolic equivalents (METs), were assessed. Results. Seventy patients (mean age = 57.5 ± 10.2 years, 77.1% males) were included into the study. At the end of rehabilitation period, the LVEF increased from 45.14 ± 5.77% to 50.44 ± 8.70% (P < 0.001), and the peak exercise capacity increased from 8.00 ± 2.56 to 10.08 ± 3.00 METs (P < 0.001). There was no significant change in LVEDD (54.63 ± 12.96 to 53.86 ± 8.95 mm, P = 0.529) or in LVESD (38.91 ± 10.83 to 38.09 ± 9.04 mm, P = 0.378) after rehabilitation. Conclusion. Exercise training in postmyocardial infarction patients with ventricular dysfunction could have beneficial effects on cardiac function without adversely affecting LV remodeling or causing serious cardiac complications. PMID:24459599

Sadeghi, Masoumeh; Garakyaraghi, Mohammad; Khosravi, Mohsen; Taghavi, Mahboobeh; Sarrafzadegan, Nizal; Roohafza, Hamidreza

2013-01-01

333

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

334

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

PubMed

The objective of this study was to evaluate the improved effectiveness of a disease management treatment protocol incorporating comprehensive lipid profiling and targeted lipid care based on lipid profile findings in patients with ischemic heart disease (IHD) or congestive heart failure (CHF) enrolled in a managed care plan. This retrospective cohort study, conducted over a 2-year period, compared outcomes between patients with a standard lipid profile to those evaluated with a comprehensive lipid profile. All adult members of the WellMed Medical Management, Inc. managed care health plan diagnosed with IHD or CHF, and continuously enrolled between July 1, 2006 and June 30, 2008, were included in the study. Cases were defined as those who had at least 1 comprehensive lipid test (the VAP [vertical auto profile] ultracentrifuge test) during this period (n=1767); they were compared to those who had no lipid testing or traditional standard lipid testing only (controls, n=289). Univariate statistics were analyzed to describe the groups, and bivariate t tests or chi-squares examined differences between the 2 cohorts. Multivariate regression analyses were performed to control for potential confounders. The results show that the case group had lower total costs ($4852.62 vs. $7413.18; P=0.0255), fewer inpatient stays (13.1% vs. 18.3% of controls; P=0.0175) and emergency department visits (11.9% vs. 15.6% of controls; P=0.0832). Prescription use and frequency of lipid measurement suggested improved control resulting from a targeted approach to managing specific dyslipidemias. A treatment protocol incorporating a comprehensive lipid profile appears to improve care and reduce utilization and costs in a disease management program for cardiac patients. PMID:22166083

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

2012-02-01

335

Cardiac arrhythmias in athletes: Clinical picture, diagnosis, rehabilitation, and prevention  

Microsoft Academic Search

When athletes present any kind of cardiac arrhythmia, it is essential to specify the underlying mechanisms and to identify the arrhythmia with the help of transesophageal computer?aided electrostimulation. This technique also allows earlier identification of previously undetected arrhythmias, specification of the underlying electro?physiologic cause and determination of the functional condition of both the conduction and pacemaking systems of the heart.

V. F. Antyufiev; M. V. Kazakov; N. A. Lepikhina; G. Y. Tayurov; N. P. Khromova

1993-01-01

336

The in vivo assessment of mechanical loadings on pectoral pacemaker implants.  

PubMed

Reduced sizes of implantable cardiac pacemakers and clinical advances have led to a higher feasibility of using such devices in younger patients including children. Increased structural demands deriving from reduced device size and more active recipients require detailed knowledge of in vivo mechanical conditions to ensure device reliability. Objective of this study was the proof of feasibility of a system for the measurement of in vivo mechanical loadings on pacemaker implants. The system comprised the following: implantable instrumented pacemaker (IPM) with six force sensors, accelerometer and radio-frequency (RF) transceiver; RF data logging system and video capture system. Three Chacma baboons (20.6+/-1.15 kg) received one pectoral sub-muscular IPM implant. After wound healing, forces were measured during physical activities. Forces during range of motion of the arm were assessed on the anaesthetized animals prior to device explantation. Mass, volume and dimensions of the excised Pectoralis major muscles were determined after device explantation. Remote IPM activation and data acquisition were reliable in the indoor cage environment with transceiver distances of up to 3m. Sampling rates of up to 1,000 Hz proved sufficient to capture dynamic in vivo loadings. Compressive forces on the IPM in conscious animals reached a maximum of 77.2+/-54.6N during physical activity and were 22.2+/-7.3N at rest, compared with 34.6+/-15.7 N maximum during range of motion and 13.4+/-3.3N at rest in anaesthetized animals. The study demonstrated the feasibility of the developed system for the assessment of in vivo mechanical loading conditions of implantable pacemakers with potential for use for other implantable therapeutic devices. PMID:20202638

de Vaal, Michael Hamman; Neville, James; Scherman, Jacques; Zilla, Peter; Litow, Micah; Franz, Thomas

2010-06-18

337

Nonlinear dynamics, chaos and complex cardiac arrhythmias  

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

338

[The best of cardiac pacing in 2005].  

PubMed

In 2005, the main subject of interest in the field of pacing was cardiac resynchronisation. The results of CARE-HF (Cardiac Resynchronisation on Morbidity and Mortality in Heart Failure), a large multicentre trial, were published. The investigators set out to establish whether resynchronisation pacing had a favourable effect on morbidity and mortality in patients with advanced cardiac failure and desynchronised compared with an identical population treated medically. The results showed that resynchronisation decreased the interventricular desynchronisation, decreased mitral regurgitation and, above all, improved symptoms and quality of life with a reduction in the incidence of complications and the risk of death. This publication is too recent for evaluation of the eventual repercussions of these results on the implantation of resynchronising pacemakers in France. The indication recommended by the scientific societies is still based on criteria which do not take echocardiographic data into account. However, the recommendations will probably change in the near future when the conclusions of trials currently under way, are published. From the technical point of view, the advances in cardiac pacing were mainly the new algorithms which avoid inappropriate ventricular stimulation of dual chamber pacemakers. It is well known that patients implanted with dual chamber pacemakers may, despite optimal adjustment of pacing parameters, have ineffective ventricular stimulation as the impulse falls in the phase of spontaneous ventricular depolarisation or effective but absolutely valueless. Several manufactures now propose pacemakers with algorithms which "search" for ventriculogrammes in order to avoid these situations of inadequate stimulation. Their efficacy has been demonstrated. Finally, in 2005, the diffusion of defibrillators equipped with a resynchronisation function has been confirmed. The conclusions of the COMPANION trial have been influential in promoting this usage although the results are mainly observed abroad. PMID:16479968

Chauvin, M

2006-01-01

339

Behavioral/Systems/Cognitive Sodium and Calcium Current-Mediated Pacemaker Neurons  

E-print Network

Behavioral/Systems/Cognitive Sodium and Calcium Current-Mediated Pacemaker Neurons and RespiratoryICAN enhanceneuronalexcitabilityandpromoterhythmogenesis,eveniftheirmagnitudeisinsufficienttosupport bursting-pacemaker activity in individual neurons excitability, which is inconsistent with a pacemaker-essential mechanism of respiratory rhythmogenesis

Del Negro, Christopher A.

340

Model-Based Conformance Testing for Implantable Pacemakers George Chen, Zhihao Jiang, Rahul Mangharam  

E-print Network

Model-Based Conformance Testing for Implantable Pacemakers George Chen, Zhihao Jiang, Rahul References Methods Testing Framework -The increasing complexity of pacemaker software has resulted the safety of pacemaker software. -Develop tools and methodologies to test and formally verify whether

Plotkin, Joshua B.

341

Limit Cycle Oscillations in Pacemaker Cells  

E-print Network

In recent decades, several mathematical models describing the pacemaker activity of the rabbit sinoatrial node have been developed. We demonstrate that it is not possible to establish the existence, uniqueness, and stability of a limit cycle oscillation in those models. Instead we observe an infinite number of limit cycles. We then display numerical results from a new model, with a limit cycle that can be reached from many different initial conditions.

Endresen, L P; Endresen, Lars Petter; Skarland, Nils

1999-01-01

342

Pacemaker failure associated with therapeutic radiation  

Microsoft Academic Search

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

Christopher Brooks; Mitchell Mutter

1988-01-01

343

Pacemaker Endocarditis Due to Propionibacterium acnes  

Microsoft Academic Search

.  \\u000a \\u000a Propionibacterium acnes belongs to the cutaneous flora of humans; it is often considered to be contaminant but has also been found to be a pathogen\\u000a in human diseases. It is an uncommon causal agent in infective endocarditis and appears to have a predilection for prosthetic\\u000a valves and foreign bodies. We describe a case of pacemaker endocarditis which shows that

K. Zedtwitz-Liebenstein; H. Gabriel; W. Graninger

2003-01-01

344

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

345

Pacemaker implantation after transcatheter aortic valve implantation.  

PubMed

Thirty- to 35% of patients after transcatheter aortic valve implantation undergo implantation of a permanent pacemaker (PPM) because of development of atrioventricular block (AVB) or development of a condition with high risk of progression to AVB. There are insufficient data regarding long-term follow-up on pacing dependency. From February 2009 to July 2011, 191 transcatheter aortic valve implantation procedures were performed at the Rabin Medical Center (125 CoreValve and 66 Edwards SAPIEN). Thirty-two patients (16.7%) received a PPM (30 with CoreValve and 2 with Edwards SAPIEN). Data from the pacemaker clinic follow-up was available in 27 patients. After a mean follow-up of 52 weeks (range, 22 to 103), only 8 (29%) of 27 patients were pacing dependent. The indication of PPM in these 8 patients was complete AVB. In conclusion, in our center, the rate of PPM implantation was 16%, which is lower than that reported in the published works. Only 29% of those patients implanted with PPM were pacemaker dependent. Further studies are necessary to define reliable predictors for long-term pacing. PMID:23998348

Goldenberg, Gustavo; Kusniec, Jairo; Kadmon, Ehud; Golovchiner, Gregory; Zabarsky, Ronit; Nevzorov, Roman; Vaknin, Hana; Assali, Abed; Kornowski, Ran; Haim, Moti; Strasberg, Boris

2013-11-15

346

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

347

21 CFR 870.3640 - Indirect pacemaker generator function analyzer.  

Code of Federal Regulations, 2012 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...

2012-04-01

348

21 CFR 870.3640 - Indirect pacemaker generator function analyzer.  

Code of Federal Regulations, 2010 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...

2010-04-01

349

21 CFR 870.3640 - Indirect pacemaker generator function analyzer.  

Code of Federal Regulations, 2011 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...

2011-04-01

350

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

351

Pulmonary and Cardiac Function in Asymptomatic Obese Subjects and Changes following a Structured Weight Reduction Program: A Prospective Observational Study  

PubMed Central

Background The prevalence of obesity is rising. Obesity can lead to cardiovascular and ventilatory complications through multiple mechanisms. Cardiac and pulmonary function in asymptomatic subjects and the effect of structured dietary programs on cardiac and pulmonary function is unclear. Objective To determine lung and cardiac function in asymptomatic obese adults and to evaluate whether weight loss positively affects functional parameters. Methods We prospectively evaluated bodyplethysmographic and echocardiographic data in asymptomatic subjects undergoing a structured one-year weight reduction program. Results 74 subjects (32 male, 42 female; mean age 42±12 years) with an average BMI 42.5±7.9, body weight 123.7±24.9 kg were enrolled. Body weight correlated negatively with vital capacity (R?=??0.42, p<0.001), FEV1 (R?=??0.497, p<0.001) and positively with P 0.1 (R?=?0.32, p?=?0.02) and myocardial mass (R?=?0.419, p?=?0.002). After 4 months the study subjects had significantly reduced their body weight (?26.0±11.8 kg) and BMI (?8.9±3.8) associated with a significant improvement of lung function (absolute changes: vital capacity +5.5±7.5% pred., p<0.001; FEV1+9.8±8.3% pred., p<0.001, ITGV+16.4±16.0% pred., p<0.001, SR tot ?17.4±41.5% pred., p<0.01). Moreover, P0.1/Pimax decreased to 47.7% (p<0.01) indicating a decreased respiratory load. The change of FEV1 correlated significantly with the change of body weight (R?=??0.31, p?=?0.03). Echocardiography demonstrated reduced myocardial wall thickness (?0.08±0.2 cm, p?=?0.02) and improved left ventricular myocardial performance index (?0.16±0.35, p?=?0.02). Mitral annular plane systolic excursion (+0.14, p?=?0.03) and pulmonary outflow acceleration time (AT +26.65±41.3 ms, p?=?0.001) increased. Conclusion Even in asymptomatic individuals obesity is associated with abnormalities in pulmonary and cardiac function and increased myocardial mass. All the abnormalities can be reversed by a weight reduction program. PMID:25233078

Held, Matthias; Mittnacht, Maria; Kolb, Martin; Karl, Sabine; Jany, Berthold

2014-01-01

352

Cardiac fluid dynamics anticipates heart adaptation.  

PubMed

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

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

2015-01-21

353

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. PMID:21794181

2011-01-01

354

What Is Cardiac Rehabilitation?  

MedlinePLUS

... if your doctor says you can. • Have your heart rate, blood pressure and EKG monitored. A cardiac rehabilitation (rehab) program takes place in a hospital or in the community. Cardiac rehab is for patients who are getting better after heart problems or surgery. One of the best things ...

355

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

356

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

357

Asynchronous response of coupled pacemaker neurons  

E-print Network

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.

Ramana Dodla; Charles J. Wilson

2009-02-03

358

Electrocution Induced Symptomatic Bradycardia Necessitating Pacemaker Implantation  

PubMed Central

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

Yew, Kuan Leong

2014-01-01

359

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

360

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

2013-05-01

361

Cardiac involvement in myotonic dystrophy  

PubMed Central

Background Myotonic dystrophy (DM) is an inherited progressive muscle disorder caused by defects in muscle proteins. As the incidence of this condition is low, not many are familiar with the multisystem involvement. At times, cardiac disease may even be the predominant manifestation in the form of arrhythmias, conduction defects, and cardiomyopathies. The progression of the disease can lead to sudden, unpredictable death. Thus, it is important to identify this subgroup and treat accordingly. Objective To identify patients with DM and assess their risk for sudden cardiac death. Methods Nine patients previously diagnosed with muscular dystrophy were evaluated by cardiologists for various reasons, from a general follow-up to cardiac arrest. All of them had electrocardiograms (EKG) and 2-D echocardiograms, and seven of them had further electrophysiological (EP) studies. Results Of the nine patients with DM, eight had EKG evidence of conduction abnormalities ranging from first-degree heart block to complete heart block. Of the seven who had EP studies, five had inducible ventricular tachycardia requiring immediate cardioversion and implantable cardioverter defibrillator (ICD) implant. Two of them underwent permanent pacemaker placement due to complete heart block and infra-Hissian block. The remaining two patients opted for a conservative approach with yearly EKG monitoring. Conclusion Because one-third of the cardiac deaths in patients with DM are sudden, there is a strong need to identify these patients and intervene in those at high risk. Prophylactic pacemaker placement is recommended even in those with minimal conduction system abnormality. However, the common practice is to identify patients at high risk of conduction abnormalities by EP studies and then provide them with prophylactic invasive strategies. PMID:25656662

Khalighi, Koroush; Kodali, Archana; Thapamagar, Suman B.; Walker, Stanley R.

2015-01-01

362

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

PubMed

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

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

2014-01-01

363

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

PubMed Central

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

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

2014-01-01

364

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

PubMed

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

Luna-Zurita, Luis; Prados, Belén; Grego-Bessa, Joaquim; Luxán, Guillermo; del Monte, Gonzalo; Benguría, Alberto; Adams, Ralf H; Pérez-Pomares, José María; de la Pompa, José Luis

2010-10-01

365

Contribution of pacemaker neurons to respiratory rhythms generation in vitro.  

PubMed

Neurons with pacemaker properties have been described in several neural networks. Nonlinearity of their bursting activity might enable them to facilitate onset of excitatory states or to synchronize neuronal ensembles. However, whether such neurons are essential for generating a network activity pattern remains mostly unknown. For the mammalian respiratory network, located in the preBötzinger complex (PBC), two types of pacemaker neurons have been described. Bursting properties of one type of pacemakers rely on the riluzole-sensitive persistent sodium current, whereas bursting mechanisms of a second type are sensitive to Cd2+ and flufenamic acid, a calcium-dependent nonspecific cationic current blocker. The role of pacemakers in the generation of respiratory rhythms in vitro is state dependent. Under control conditions, the respiratory network generates fictive eupneic activity; this activity depends on both riluzole-sensitive and flufenamic acid-sensitive pacemakers. During hypoxia, fictive eupneic activity is supplanted by the neural correlate of gasping and only riluzole-sensitive pacemaker neurons appear to be necessary for this rhythm. Thus, at least two types of pacemaker bursting mechanisms are present in the PBC and underlie fictive eupnea, whereas only one burst mechanism seems to be critical for gasping generation in vitro. PMID:18085257

Peña, Fernando

2008-01-01

366

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

Microsoft Academic Search

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

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

1997-01-01

367

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

Microsoft Academic Search

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

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

1997-01-01

368

HHMIMedintoGradProgram,Winter2009 Research Proposal: The Role of Cardiac Fibroblasts in Calcific Aortic Stenosis  

E-print Network

hypertrophy in response to pressure overload. Cardiac hypertrophy can lead to eventual congestive heart hypertrophy and CHF. While fibroblasts play an essential role in fibrotic disease progression and have been are known to be major contributors to fibrosis and adverse cardiac remodeling during cardiac hypertrophy

Gleeson, Joseph G.

369

Preliminary experience with the use of a programmable pacemaker.  

PubMed

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

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

1975-05-01

370

Delayed timing of heart and arterial sounds in patients with implanted pacemakers.  

PubMed

We have recorded the timing of the heart sounds and the arterial sounds with reference to the onset of each cardiac cycle in 16 patients before and after implantation of a pacemaker prosthesis, and in an additional 18 patients after pacemaker implantation only. The interval between the QRS complex and the Korotkoff sound at diastolic pressure (QKd) is markedly prolonged, from 206 to 294 msec., a change corresponding to 10 standard errors of the mean difference. Likewise, the Q-Korotkoff interval at systolic pressure (QKs) is prolonged from 329 to 414 msec. The interval between the QRS complex and the onset of the first sound (S1) is prolonged by approximately 90 msec., whereas the interval between the QRS and the second heart sound (S2) is prolonged by 70 msec. We noted an associated increase in heart rate, a slight decrease in systolic pressure, an increase in diastolic pressure, a decrease in pulse pressure, and a slight decrease in the deltaP/deltat at the brachial artery measured indirectly and noninvasively. PMID:933552

Hasegawa, M; Rodbard, S

1976-07-01

371

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

PubMed Central

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

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

2013-01-01

372

Reuse of pacemakers and defibrillators in developing countries: logistical, legal, and ethical barriers and solutions.  

PubMed

In the wealthy nations of the world, access to implantable cardiac rhythm management devices is widespread. In many underserved low- and middle-income countries (LMIC), where cardiovascular disease is fast becoming a major public health problem, access is often limited. Reuse of pulse generators was practiced regularly in some European nations in the 1990s with good results. It is performed in LMIC, although the rates of device reuse are unknown. The available literature suggests there is no increased risk of morbidity or mortality with the reuse of devices. Donations of pacemaker and defibrillator pulse generators from developed nations constitute an important source of devices for the poor in LMIC. There are opportunities to increase this supply, but logistical barriers and legal and ethical concerns must be addressed. With proper sterilization, meticulous chains of custody, and advance directives for device handling (pacemaker/defibrillator living wills), patients in LMIC who would otherwise lack access to these devices could benefit from their reuse. PMID:20430113

Kirkpatrick, James N; Papini, Christina; Baman, Timir S; Kota, Karthik; Khota, Karthik; Eagle, Kim A; Verdino, Ralph J; Caplan, Arthur L

2010-11-01

373

Heart rate during exercise: what is the optimal goal of rate adaptive pacemaker therapy?  

PubMed

The objective of minute ventilation (MV)-controlled pacemaker algorithms is to simulate the physiologic relationship of the sensed signal and the sinus node response during exercise. In our study we determined the relationship between heart rate and MV in healthy middle-aged subjects by measuring breath-by-breath gas exchange throughout peak exercise. Regarding several clinical limitations of peak exercise testing, we additionally evaluated whether a 35 W low-intensity treadmill exercise (LITE) protocol can be used as a substitute for peak exercise testing to determine the physiologic heart rate to MV slope. The results demonstrated that the heart rate to MV relationship is not linear throughout peak exercise but is curvilinear with a smooth logarithmic-type profile. To simulate this relationship, MV-based rate adaptive pacemakers should generate a decreasing heart rate to MV slope during higher levels of work. The heart rate to MV slope determined during the early, dynamic phase of low-intensity exercise represents the same slope derived from peak exercise below the anaerobic threshold. The low-intensity treadmill exercise protocol, with minimal patient effort, can thus be used as a substitute for peak exercise to optimize rate adaptive slope programming of MV-controlled pacemakers. PMID:8160576

Lewalter, T; Jung, W; MacCarter, D; Bauer, T; Schimpf, R; Manz, M; Lüderitz, B

1994-04-01

374

[{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

375

Bladder pacemaker: scientific basis and clinical future.  

PubMed

Complete intermittent emptying of the denervated bladder is essential to maintain the integrity of the urinary tract. Intraspinal extradural segments of the sacral roots in the canine can be stimulated electrically to induce bladder emptying effectively, especially in conjunction with selective neurotomy to make the stimulus pure autonomic effect on the bladder wall itself. With varying parameters of stimulation, one also can induce sustained voluntary sphincter activity to maintain continence--which obviates the problem of skeletal muscle fatigue. Combination of the two--detrusor stimulation for emptying and sphincteric stimulation to achieve control--are the first steps toward utilization of an electronic bladder pacemaker in the presence of an intact reflex arc. Its use in humans will be possible in the near future. PMID:7179629

Tanagho, E A; Schmidt, R A

1982-12-01

376

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

PubMed

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

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

2014-01-01

377

21 CFR 870.3720 - Pacemaker electrode function tester.  

Code of Federal Regulations, 2012 CFR

...a device which is connected to an implanted pacemaker lead that supplies an accurately calibrated, variable pacing pulse for measuring the patient's pacing threshold and intracardiac R-wave potential. (b) Classification. Class II...

2012-04-01

378

21 CFR 870.3720 - Pacemaker electrode function tester.  

Code of Federal Regulations, 2014 CFR

...a device which is connected to an implanted pacemaker lead that supplies an accurately calibrated, variable pacing pulse for measuring the patient's pacing threshold and intracardiac R-wave potential. (b) Classification. Class II...

2014-04-01

379

21 CFR 870.3720 - Pacemaker electrode function tester.  

Code of Federal Regulations, 2013 CFR

...a device which is connected to an implanted pacemaker lead that supplies an accurately calibrated, variable pacing pulse for measuring the patient's pacing threshold and intracardiac R-wave potential. (b) Classification. Class II...

2013-04-01

380

Pacemakers and defibrillators: recent and ongoing studies that impact the elderly.  

PubMed

Since the first implantation of a cardiac pacemaker in the second half of the 20th century, there have been evolutionary and revolutionary advances in the technology developed for patients with heart rhythm disturbances. These advances, however, have instead failed to demonstrate that mimicry of physiology by a pacing system would deliver a longer and better life to its recipient. Indeed, we are just now in the process of developing a new paradigm in pacing that may finally deliver physiology to the hyperbolically named "physiologic pacing." This article will discuss the reasons for the discrepancy between the earlier studies and the more recent ones, as well as a review of implantable cardioverter-defibrillator trials, keeping in focus the special needs of aged heart rhythm device recipients. PMID:16525220

Martinez, Claudia; Tzur, Assaf; Hrachian, Hakop; Zebede, Joseph; Lamas, Gervasio A

2006-01-01

381

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

PubMed

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

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

2015-01-01

382

Biomechanics of Early Cardiac Development  

PubMed Central

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.

2012-01-01

383

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

PubMed Central

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

2013-01-01

384

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

385

Pacemaker implantation in patients with persistent left superior vena cava.  

PubMed

Implantation of a permanent pacemaker system is most commonly performed by puncturing the left subclavian vein and introducing the pacemaker lead(s) through the superior caval vein to the right atrium and/or ventricle. Occasionally, a persistent left superior caval vein is encountered peroperatively, complicating the procedure. This article describes three such patients and provides a review of the literature regarding one of the most common anomalies of the thoracic vessels. PMID:15168065

Lappegård, Knut Tore; Prytz, Jan F; Haug, Bjørn

2004-05-01

386

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. PMID:23409835

2013-01-01

387

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

388

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

389

Predictors of Severe Tricuspid Regurgitation in Patients with Permanent Pacemaker or Automatic Implantable Cardioverter-Defibrillator Leads  

PubMed Central

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

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

2013-01-01

390

Tornado in a dish: Revealing the mechanisms of ventricular arrhythmias in engineered cardiac tissues  

E-print Network

cardiac tissues Igor R. Efimov *, Crystal M. Ripplinger Washington University, St. Louis, MO, USA Received that they all center around two ideas, viz., (a) that the impulses arise from centers, or pacemakers, or (b on recent experimental advances, this hypothesis has been further developed into the ``mother rotor'' theory

391

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

392

Heart Rhythm and Cardiac Pacing: An Integrated Dual-Chamber Heart and Pacer Model  

Microsoft Academic Search

Modern cardiac pacemaker can sense electrical activity in both atrium and ventricle, and deliver precisely timed stimulations\\u000a to one or both chambers on demand. However, little is known about how the external cardiac pacing interacts with the heart’s\\u000a intrinsic activity. In this study, we present an integrated dual-chamber heart and pacer (IDHP) model to simulate atrial and\\u000a ventricular rhythms in

Jie Lian; Dirk Müssig

2009-01-01

393

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

PubMed

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

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

2011-01-01

394

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

SciTech Connect

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

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

1984-10-01

395

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

PubMed

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

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

2014-10-01

396

Cardiac Amyloidosis  

MedlinePLUS

... pdf/view ). Previous Section Next Section Sources of Funding Dr Quarta received funding from the “Istituto Nazionale per le Ricerche Cardiovascolari ( ... Women's Hospital Cardiac Amyloidosis Fund. Dr Falk received funding from the Brigham and Women's Hospital Cardiac Amyloidosis ...

397

Are Electronic Cardiac Devices Still Evolving?  

PubMed Central

Summary Objectives The goal of this paper is to review some important issues occurring during the past year in Implantable devices. Methods First cardiac implantable device was proposed to maintain an adequate heart rate, either because the heart’s natural pacemaker is not fast enough, or there is a block in the heart’s electrical conduction system. During the last forty years, pacemakers have evolved considerably and become programmable and allow to configure specific patient optimum pacing modes. Various technological aspects (electrodes, connectors, algorithms diagnosis, therapies, …) have been progressed and cardiac implants address several clinical applications: management of arrhythmias, cardioversion / defibrillation and cardiac resynchronization therapy. Results Observed progress was the miniaturization of device, increased longevity, coupled with efficient pacing functions, multisite pacing modes, leadless pacing and also a better recognition of supraventricular or ventricular tachycardia’s in order to deliver appropriate therapy. Subcutaneous implant, new modes of stimulation (leadless implant or ultrasound lead), quadripolar lead and new sensor or new algorithm for the hemodynamic management are introduced and briefly described. Each times, the main result occurring during the two past years are underlined and repositioned from the history, remaining limitations are also addressed. Conclusion Some important technological improvements were described. Nevertheless, news trends for the future are also considered in a specific session such as the remote follow-up of the patient or the treatment of heart failure by neuromodulation. PMID:25123732

Mabo, P.

2014-01-01

398

Technology utilization program report  

NASA Technical Reports Server (NTRS)

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

1974-01-01

399

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

400

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

401

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

ERIC Educational Resources Information Center

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

Gutin, Bernard

402

Nonphotic entrainment of the human circadian pacemaker  

NASA Technical Reports Server (NTRS)

In organisms as diverse as single-celled algae and humans, light is the primary stimulus mediating entrainment of the circadian biological clock. Reports that some totally blind individuals appear entrained to the 24-h day have suggested that nonphotic stimuli may also be effective circadian synchronizers in humans, although the nonphotic stimuli are probably comparatively weak synchronizers, because the circadian rhythms of many totally blind individuals "free run" even when they maintain a 24-h activity-rest schedule. To investigate entrainment by nonphotic synchronizers, we studied the endogenous circadian melatonin and core body temperature rhythms of 15 totally blind subjects who lacked conscious light perception and exhibited no suppression of plasma melatonin in response to ocular bright-light exposure. Nine of these fifteen blind individuals were able to maintain synchronization to the 24-h day, albeit often at an atypical phase angle of entrainment. Nonphotic stimuli also synchronized the endogenous circadian rhythms of a totally blind individual to a non-24-h schedule while living in constant near darkness. We conclude that nonphotic stimuli can entrain the human circadian pacemaker in some individuals lacking ocular circadian photoreception.

Klerman, E. B.; Rimmer, D. W.; Dijk, D. J.; Kronauer, R. E.; Rizzo, J. F. 3rd; Czeisler, C. A.

1998-01-01

403

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. PMID:24151580

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

2013-01-01

404

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

PubMed

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

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

2015-03-01

405

Spiral-pacemaker interactions in a mathematical model of excitable medium  

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

406

Transcatheter aortic valve replacement: establishing a comprehensive program model for hybrid cardiac catheterization laboratories in the Department of Veterans Affairs.  

PubMed

Aortic valve disease, especially aortic stenosis, becomes progressively debilitating and carries a high mortality risk if it is categorized as severe and symptomatic (J Thorac Cardiovas Surg. 2012;144(3):e29-e84). In the past, the only treatment for aortic stenosis was surgical aortic valve replacement. Surgical treatment may require several hours of cardioplegia, and if the patient has comorbidities, such as renal failure or chronic obstructive pulmonary disease, their operative mortality percentage increases.In 2011, the US Food and Drug Administration approved the use of a transcatheter aortic valve replacement (TAVR) procedure for patients who were deemed high risk or inoperative for the routine surgical aortic valve replacement surgery. More than 20,?000 TAVRs have been performed in patients worldwide since 2002 when Dr Alain Cribier performed the first-in-man TAVR (Arch Cardiovasc Dis. 2012;105(3):145-152). The Edwards Lifesciences SAPIEN XT valve and the Medtronic CoreValve are commercially available.The clinical findings and economic statistic have supported the expansion of the TAVR procedure. However, there has been considerable controversy over where the procedure is to occur and who is directly responsible for directing the TAVR care. This debate has identified barriers to the implementation of a TAVR program. The operating rooms and a cardiac catheterization laboratory are underprepared for the hybrid valve replacement therapy. Because of the barriers identified, the Department of Veterans Affairs determined a need for a systematic approach to review the programs that applied for this structural heart disease program. A centralized team was developed to ensure room readiness and staff competency. The use of the Health Failure Mode and Effects Analysis can define high-risk clinical processes and conduct a hazard analysis. Worksheets can show potential failure modes and their probabilities, along with actions and outcome measures, team collaboration, extensive screening, and selection process. The TAVR program begins implementation with data entry with each case into CART-CL (Cardiovascular Assessment, Reporting and Tracking System for Cath Labs, Veteran Administration database for interventional cardiology procedures). If an untoward event occurs, within 24 hours the CART-CL Quality Assessment Team is activated to begin the review process. This provides real-time review and feedback to the local facility in an expeditious manner. Cardiac catheterization laboratories have been inundated with rapidly changing technological advances in the past decade. The era for structural heart repair is rapidly mobilizing from a surgical/operating room setting to a transcatheter/hybrid catheterization laboratory suite. The use of the new hybrid catheterization laboratories will continue to expand as the approval of future transcatheter therapies evolve. Editor's note: Due to the volume of important information presented in each table, only the first table is included in the print version of the article, however, all tables may be viewed in their entirety free of charge on the online version of this article: http://journals.lww.com/dccnjournal/pages/default.aspx. PMID:25144213

Speiser, Bernadette; Dutra-Brice, Cynthia

2014-01-01

407

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 PMID:23968340

2013-01-01

408

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

Microsoft Academic Search

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

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

2000-01-01

409

Biasing the pacemaker in the behavioral theory of timing  

PubMed Central

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

Bizo, Lewis A.; White, K. Geoffrey

1995-01-01

410

The neurochemical basis of photic entrainment of the circadian pacemaker  

NASA Technical Reports Server (NTRS)

Circadian rhythmicity in mammals is controlled by the action of a light-entrainable hypothalamus, in association with two cell clusters known as the supra chiasmatic nuclei (SCN). In the absence of temporal environmental clues, this pacemaker continues to measure time by an endogenous mechanism (clock), driving biochemical, physiological, and behavioral rhythms that reflect the natural period of the pacemaker oscillation. This endogenous period usually differs slightly from 24 hours (i.e., circadian). When mammals are maintained under a 24 hour light-dark (LD) cycle, the pacemaker becomes entrained such that the period of the pacemaker oscillation matches that of the LD cycle. Potentially entraining photic information is conveyed to the SCN via a direct retinal projection, the retinohypothalamic tract (RHT). RHT neurotransmission is thought to be mediated by the release of excitatory amino acids (EAA) in the SCN. In support of this hypothesis, recent experiments using nocturnal rodents have shown that EAA antagonists block the effects of light on pacemaker-driven behavioral rhythms, and attenuate light induced gene expression in SCN cells. An understanding of the neurochemical basis of the photic entrainment process would facilitate the development of pharmacological strategies for maintaining synchrony among shift workers in environments, such as the Space Station, which provide unreliable or conflicting temporal photic clues.

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

1992-01-01

411

Surgical removal of a giant vegetation on permanent endocavitary pacemaker wire and lead.  

PubMed

Pacemaker lead infections are rare. There are only about 0.4%-1.1% of the patients who have been implanted permanent pacemakers suffering from serious infections which lead to endocarditis. Generally, removal of the infected pacemaker wire and lead, long-term anti-infection therapy, and implantation of a new pacemaker to another anatomic site are accepted approaches for these patients. PMID:22218056

Guo-tao, Ma; Qi, Miao; Chao-ji, Zhang; Li-hua, Cao

2011-12-01

412

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

PubMed

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

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

2014-01-01

413

Extreme Events as Pacemaker of Adaptation to Climate Change1 William R. Travis  

E-print Network

1 Extreme Events as Pacemaker of Adaptation to Climate Change1 William R. Travis Department as potentially efficient pacemakers of adaptation (Larsen et al., 2008). The title of the IPCC special report, the pacemaker effect of extremes. Recent analyses of (and debates over) attribution of extreme events to climate

Neff, Jason

414

Asynchronous Response of Coupled Pacemaker Neurons Ramana Dodla and Charles J. Wilson  

E-print Network

Asynchronous Response of Coupled Pacemaker Neurons Ramana Dodla and Charles J. Wilson Department; published 10 February 2009) We study a network model of two conductance-based pacemaker neurons of differing. We consider two coupled pacemaking model neurons at dissimilar frequencies (!1;2) and affected

Dodla, Ramana

415

Result: Pacemakers drift to attractors Integral of the excitation variable u along  

E-print Network

Result: Pacemakers drift to attractors Integral of the excitation variable u along: (a Panfilov, RH Keldermann & MP Nash. Self-organized pacemakers in a coupled reaction of ectopic pacemaking due to mechano-electrical feedback (MEF) via stretch- activated channels (SACs

Utrecht, Universiteit

416

Pacemakers in large arrays of oscillators with nonlocal coupling Gabriela Jaramillo and Arnd Scheel  

E-print Network

Pacemakers in large arrays of oscillators with nonlocal coupling Gabriela Jaramillo and Arnd Scheel September 3, 2014 Abstract We model pacemaker effects of an algebraically localized heterogeneity in a 1-amplitude descriptions near Hopf bifurcations. Our interest here focuses modestly on a rigorous description of pacemakers

Scheel, Arnd

417

Does Rapid Auditory Stimulation Accelerate an Internal Pacemaker? Don't Bet on It.  

E-print Network

Does Rapid Auditory Stimulation Accelerate an Internal Pacemaker? Don't Bet on It. Bruno H. Repp, Connecticut, USA Unpublished manuscript (2011) with an addendum (2012). #12;Repp & Mendlowitz: Pacemaker of an internal pacemaker by RAS. The present study used musically trained participants in two experiments

418

Pacemaker Neurons for the Theta Rhythm and Their Synchronization in the Septohippocampal Reciprocal Loop  

E-print Network

Pacemaker Neurons for the Theta Rhythm and Their Synchronization in the Septohippocampal Reciprocal-9110 Received 16 February 2001; accepted in final form 15 October 2001 Wang, Xiao-Jing. Pacemaker neurons. On the other hand, experimental data indicate that GABAergic cells in the medial septum play a pacemaker role

Wang, Xiao-Jing

419

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Federal Register Volume 77, Number 121...Implantable Pacemaker Pulse Generator AGENCY: Food and...controls), class II (special controls...implantable pacemaker pulse generator closed October 25...implanted pacemaker pulse generator. The comment was...classification of the device. II. Findings With...

2012-06-22

420

Pacemaker's Functional Behaviors in Event-B Dominique Mery and Neeraj Kumar Singh  

E-print Network

is necessary either because the heart's native Pacemaker is insufficiently fast or there is a block, Pacemaker, Electrode, Heart 1 Introduction For centuries, people became ill and died. Today, with our at an alarming rate [2]. Pacemaker is one of the hardware device for controlling the heart rate in medical domain

Paris-Sud XI, Université de

421

The Prevalence and Contents of Advance Directives in Patients With Pacemakers  

PubMed Central

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

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

2013-01-01

422

Islet 1 is Expressed in Distinct Cardiovascular Lineages, Including Pacemaker and Coronary Vascular Cells  

PubMed Central

Islet1 (Isl1) is a LIM homedomain protein that plays a pivotal role in cardiac progenitors of the second heart field. Here, lineage studies with an inducible isl1-cre demonstrated that most Isl1 progenitors have migrated into the heart by E9. Although Isl1 expression is downregulated in most cardiac progenitors as they differentiate, analysis of an isl1-nlacZ mouse and coimmunostaining for Isl1 and lineage markers demonstrated that Isl1 is expressed in distinct subdomains of the heart, and in diverse cardiovascular lineages. Isl1 expression was observed in myocardial lineages of the distal outflow tract, atrial septum, and in sinoatrial and atrioventricular node. The myocardialized septum of the outflow tract was found to derive from Isl1 expressing cells. Isl1 expressing cells also contribute to endothelial and vascular smooth muscle lineages including smooth muscle of the coronary vessels. Our data indicate that Isl1 is a specific marker for a subset of pacemaker cells at developmental stages examined, and suggest genetic heterogeneity within the central conduction system and coronary smooth muscle. Our studies suggest a role for Isl1 in these distinct domains of expression within the heart. PMID:17258700

Sun, Yunfu; Liang, Xingqun; Najafi, Nader; Cass, Margaret; Lin, Lizhu; Cai, Chengleng; Chen, Ju; Evans, Sylvia

2007-01-01

423

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

The Coronary Artery Risk Detection In Appalachian Communities (CARDIAC) Project has screened more than 80,000 children (10-12 years) for cardiovascular and diabetes risk factors over the past 15 years. Simultaneous referral and intervention efforts have also contributed to the overall program impact. In this study, we examined evidence of programmatic impact in the past decade at the individual, family, community, and policy levels from child screening outcomes, referral rates, participation in subsequent services, and policies that embed the activities of the project as a significant element. Within this period of time, fifth-grade overweight and obesity rates were maintained at a time when rates elsewhere increased. 107 children were referred for additional screening and treatment for probable familial hypercholesterolemia (FH); 82 family members were subsequently screened in family-based screening efforts. 58 grants were distributed throughout the state for community-appropriate obesity intervention. A state wellness policy embedded CARDIAC as the method of assessment and national child cholesterol screening guidelines were impacted by CARDIAC findings. The sustainability and successful impact of this school-based program within a largely underserved, rural Appalachian state are also discussed. PMID:23840946

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

2013-01-01

424

Experimental evidence of a chaotic region in a neural pacemaker  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

425

[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

426

Permanent pacemakers and implantable defibrillators: considerations for intensivists.  

PubMed

Pacemakers and cardioverter-defibrillators are implanted in patients with cardiovascular disease for an ever-increasing array of indications. Intensivists provide care frequently for patients who have these devices, and thus, they must be familiar with common problems and nuances that may contribute to critical illness. Close collaboration of the critical care physician and cardiologist/electrophysiologist assures that pacemakers and defibrillators are tuned to optimize the hemodynamic milieu of critically ill patients. Many recent advances in the sophistication of implanted devices are reviewed herein. PMID:15297272

McPherson, Craig A; Manthous, Constantine

2004-11-01

427

Interference with the pacemakers of two workers at electricity substations.  

PubMed Central

Pacemaker function was tested in two electricity substation workers exposed to high tension electric fields. High intensity electric fields induced reversion to the interference mode, producing in one case competitive rhythm and in the other inappropriately slow pacing which resulted in asymptomatic pauses of up to 2.5 s. A suit designed to shield the body from the effects of high intensity electric fields was tried and proved to be effective in protecting the pacemaker, allowing it to function normally in the substations. Images PMID:6626476

Butrous, G S; Bexton, R S; Barton, D G; Male, J C; Camm, A J

1983-01-01

428

[Cardiac sarcoidosis].  

PubMed

Cardiac sarcoidosis induces heart failure death or sudden death in many cases and is thus often associated with a poor prognosis. In Japan 47-78% of sarcoidosis patients die of cardiac lesions. Early diagnosis is important in such cases, and a comprehensive judgment based on the endomyocardial biopsy, echocardiography and nuclear medicine examination findings should be made according to the 'Handbook of the Diagnosis of Cardiac Sarcoidosis'. Once a diagnosis is made the introduction of steroid therapy should be considered. Steroid administration should be conducted referring to the 'Guidelines to the Treatment of Cardiac Sarcoidosis'. PMID:12233077

Uemura, Akihisa; Morimoto, Shin-ichiro

2002-09-01

429

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

PubMed

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

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

2012-11-01

430

Enhancement of the non-invasive electroenterogram to identify intestinal pacemaker activity.  

PubMed

Surface recording of electroenterogram (EEnG) is a non-invasive method for monitoring intestinal myoelectrical activity. However, surface EEnG is seriously affected by a variety of interferences: cardiac activity, respiration, very low frequency components and movement artefacts. The aim of this study is to eliminate respiratory interference and very low frequency components from external EEnG recording by means of empirical mode decomposition (EMD), so as to obtain more robust indicators of intestinal pacemaker activity from the external EEnG signal. For this purpose, 11 recording sessions were performed in an animal model under fasting conditions and in each individual session the myoelectrical signal was recorded simultaneously in the intestinal serosa and the external abdominal surface in physiological states. Various parameters have been proposed for evaluating the efficacy of the method in reducing interferences: the signal-to-interference ratio (S/I ratio), attenuation of the target and interference signals, the normal slow wave percentage and the stability of the dominant frequency (DF) of the signal. The results show that the S/I ratio of the processed signals is significantly greater than the original values (9.66 +/- 4.44 dB versus 1.23 +/- 5.13 dB), while the target signal was barely attenuated (-0.63 +/- 1.02 dB). The application of the EMD method also increased the percentage of the normal slow wave to 100% in each individual session and enabled the stability of the DF of the external signal to be increased considerably. Furthermore, the variation coefficient of the DF derived from the external processed signals is comparable to the coefficient obtained using internal recordings. Therefore, the EMD method could be a very useful tool to improve the quality of external EEnG recording in the low frequency range and therefore to obtain more robust indicators of the intestinal pacemaker activity from non-invasive EEnG recordings. PMID:19636086

Ye-Lin, Y; Garcia-Casado, J; Prats-Boluda, G; Ponce, J L; Martinez-de-Juan, J L

2009-09-01

431

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

E-print Network

Self-Organized Pacemakers in a Coupled Reaction-Diffusion-Mechanics System A. V. Panfilov and R. H pacemaking activity. Pacemaking is shown to occur after a single electrical or mechanical stimulus existence. We show that self-organized pacemakers drift throughout the medium to approach attractors

Utrecht, Universiteit

432

Biology in Engineering Certificate Program  

E-print Network

of courses General biology ­ 5 credits Advanced biology ­ at least 5 credits Biology in Engineering course and Neurobiology (BME) Biomechanics of Muscle Strain Injuries (ME) Computer Modeling of Cardiac Function (BME implants Prosthetic joints Hyperthermic tumor ablation in the liver Motor neural prosthetics Pacemakers

Van Veen, Barry D.

433

The Acute Effects of Changes to AV Delay on Blood Pressure and Stroke Volume: Potential Implications for Design of Pacemaker Optimization Protocols  

PubMed Central

Background Atrioventricular (AV) delay optimization of biventricular pacemakers (cardiac resynchronization therapy, CRT) may maximise hemodynamic benefit, but consumes specialist time to conduct echocardiographically. Non-invasive blood pressure monitoring is a potentially-automatable alternative, but it is unknown whether it gives the same information, and similar precision (signal-to-noise ratio). Moreover, the immediate blood pressure increment on optimization has been reported to decay away: it is unclear whether this is the result of an (undesirable) fall in stroke volume or a (desirable) compensatory relief of peripheral vasoconstriction. Methods and Results To discriminate between these alternative mechanisms, we measured simultaneous beat-to-beat stroke volume (flow) using Doppler echocardiography, and blood pressure (BP) using finger photoplethysmography, during and after atrioventricular delay changes from 40 to 120 ms in 19 subjects with cardiac pacemakers. BP and stroke volume both increased immediately (p<0.001, within one heartbeat). BP showed a clear decline a few seconds later (average rate ?0.65mmHg/beat, r=0.95 [95% CI 0.86 to 0.98]); in contrast, stroke volume did not decline (p=0.87). The immediate BP increment correlated strongly with the stroke volume increment (r=0.74, p<0.001). Signal-to-noise ratio was threefold better for BP than stroke volume (6.8±3.5 versus 2.3±1.4, p<0.001). Conclusions Improving atrioventricular delay immediately increases blood pressure, but the effect begins to decay within a few seconds. Reassuringly this is due to compensatory vasodilatation rather than reduction in cardiac function. Pacemaker optimization will never be reliable unless there is adequate signal-to-noise ratio. Using BP rather than Doppler minimises noise. The early phase – before vascular compensation – has the richest signal lode. PMID:22095639

Manisty, Charlotte H.; Al-Hussaini, Ali; Unsworth, Beth; Baruah, Resham; Pabari, Punam A.; Mayet, Jamil; Hughes, Alun D.; Whinnett, Zachary I.; Francis, Darrel P.

2012-01-01

434

Differentially Timed Extracellular Signals Synchronize Pacemaker Neuron Clocks  

PubMed Central

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

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

2014-01-01

435

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

436

Culture and transplantation of the mammalian circadian pacemaker.  

PubMed

In transplantation studies using the tau mutation in the golden hamster, it has been demonstrated that suprachiasmatic nucleus (SCN) pacemaker cells and mechanisms of communication with the host brain are retained even after tissue dissociation and maintenance for many weeks in primary cell culture. Brain grafts of cultured SCN cells are capable of restoring overt rhythms of locomotor activity, and preliminary studies where cells from two tau genotypes are combined in a single graft demonstrate that pacemaker cells may communicate with each other to produce coherent rhythms with intermediate periods. The opportunity is presented, therefore, to study pacemaker-pacemaker communication in circadian chimeras produced by SCN transplantation. Immunocytochemical analysis of graft-host interactions requires the positive identification of host versus donor cells. Although grafted blocks of tissue are easily recognized during immunocytochemical analysis, implants of dissociated and cultured cells may be more diffusely located and are not as readily identified. Unless distinct strain- or species-specific markers are available, it is difficult to identify connections that may carry timing information to the host organism. We have taken an anatomical approach that utilizes cell-labeling techniques for hamster tissue along with foreign protein expression in transgenic mice to identify patterns of communication among graft and host cells, focusing specifically on SCN-SCN communication. The data indicate the usefulness of these transgenes as markers in transplantation studies where communication between graft and host is addressed. PMID:8274766

Ralph, M R; Joyner, A L; Lehman, M N

1993-01-01

437

Inter-Association Task Force Recommendations on Emergency Preparedness and Management of Sudden Cardiac Arrest in High School and College Athletic Programs: A Consensus Statement  

PubMed Central

Objective: To assist high school and college athletic programs prepare for and respond to a sudden cardiac arrest (SCA). This consensus statement summarizes our current understanding of SCA in young athletes, defines the necessary elements for emergency preparedness, and establishes uniform treatment protocols for the management of SCA. Background: Sudden cardiac arrest is the leading cause of death in young athletes. The increasing presence of and timely access to automated external defibrillators (AEDs) at sporting events provides a means of early defibrillation and the potential for effective secondary prevention of sudden cardiac death. An Inter-Association Task Force was sponsored by the National Athletic Trainers' Association to develop consensus recommendations on emergency preparedness and management of SCA in athletes. Recommendations: Comprehensive emergency planning is needed for high school and college athletic programs to ensure an efficient and structured response to SCA. Essential elements of an emergency action plan include establishment of an effective communication system, training of anticipated responders in cardiopulmonary resuscitation and AED use, access to an AED for early defibrillation, acquisition of necessary emergency equipment, coordination and integration of on-site responder and AED programs with the local emergency medical services system, and practice and review of the response plan. Prompt recognition of SCA, early activation of the emergency medical services system, the presence of a trained rescuer to initiate cardiopulmonary resuscitation, and access to early defibrillation are critical in the management of SCA. In any collapsed and unresponsive athlete, SCA should be suspected and an AED applied as soon as possible for rhythm analysis and defibrillation if indicated. PMID:17597956

Drezner, Jonathan A; Courson, Ron W; Roberts, William O; Mosesso, Vincent N; Link, Mark S; Maron, Barry J

2007-01-01

438

From syncitium to regulated pump: a cardiac muscle cellular update  

NSDL National Science Digital Library

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

PhD Donna H. Korzick (Pennsylvania State University Dept. of Physiology and Kinesiology)

2011-03-01

439

Stem cells and cardiac regeneration.  

PubMed

Despite many advances in cardiovascular medicine, heart failure (HF) remains the leading cause of death in developed countries affecting at least 10 million people in Western Europe alone. The poor long-term prognosis of HF patients, and immense public health implications has fuelled interest in finding new therapeutic modalities. Recent observations of the beneficial effect of stem cells on the damaged heart in animal experiments have generated tremendous excitement and stimulated clinical studies suggesting that this approach is feasible, safe, and potentially effective in humans. Cell-based myocardial regeneration is currently explored for a wide range of cardiac disease states, including acute and chronic ischemic myocardial damage, cardiomyopathy and as biological heart pacemakers. The aim of the present manuscript is to review the work that has been done to establish the role of stem cells in cardiac repair, give an update on the clinical trials performed so far, as well as to discuss critically the controversies, challenges and future surrounding this novel therapeutic concept. PMID:17555531

Kocher, Alfred A; Schlechta, Bernhard; Gasparovicova, Aneta; Wolner, Ernst; Bonaros, Nikolaos; Laufer, Günther

2007-09-01

440

[The best of cardiac pacing in 1999].  

PubMed

Since the first clinical application to man forty years ago, for the treatment of bradycardia, cardiac pacing has been the object of continuous technological innovation in parallel with those in electronics and computerisation. However, independently of these expected advances, there has been a surprising widening of the field of application of pacing into those of haemodynamics and rhythmology. The recent publication of the long-term results of the Pacing in Cardiomyopathy (PIC) study confirmed the sustained decrease of intraventricular pressure gradient, of NYHA functional stage and improved quality of life of patients with hypertrophic obstructive cardiomyopathy paced in the DDD mode. The investigators also underlined the placebo effect of the pacemaker. The decrease in risk of sudden death and the reduction in ventricular remodelling have not been demonstrated yet. More recently, biventricular pacing has been proposed for the treatment of dilated cardiomyopathy and a French study showed a long-term improvement in NYHA stage and effort capacity. Several prospective randomised trials are under way to validate this indication. Acute haemodynamic evaluations have confirmed the efficacy of biventricular stimulation but also underline the value of left ventricular pacing alone. The effects on mortality, the selection of patients and the optimal configuration of pacing remain to be defined. In the field of prevention of atrial arrhythmias, the results of the multicenter SYNBIAPACE study, investigating biatrial pacing in patients with interatrial conduction defects, only showed a tendency to an increase in the delay before recurrence of atrial fibrillation. The value of the memory functions of pacemakers and the algorithms of prevention of atrial arrhythmias are still under investigation. Haemodynamic transducers have been introduced in some recent pacemakers to assess myocardial contractility and have applications in the evaluation of different pacing modes and in the optimisation of the atrioventricular interval. Their value in the treatment of neurocardiogenic syncope is under evaluation. In conclusion, it is not overoptimistic to imagine that, in the near future, the cardiac pacemaker will be part of a "control and treatment system" well over the limits of treating patients with bradycardia. PMID:10721447

Deharo, J C

2000-01-01

441

Cardiac Catheterization  

MedlinePLUS

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

442

CARDIAC MUSCLE  

PubMed Central

Cardiac muscle fibers of the hummingbird and finch have no transverse tubules and are smaller in diameter than those of mammalian hearts. The fibers are connected by intercalated discs which are composed of desmosomes and f. adherentes; small nexuses are often interspersed. As in cardiac muscle of several other animals, the junctional SR of the couplings is highly structured in these two birds but, in addition, and after having lost sarcolemmal contact, the junctional SR continues beyond the coupling to extend deep into the interior of the cells and to form belts around the Z-I regions of the sarcomeres. This portion of the sarcoplasmic reticulum, which we have named "extended junctional SR," and which is so prominent and invariant a feature of cardiac cells of hummingbirds and finches, has not been observed in chicken cardiac cells. The morphological differences between these species of birds may be related to respective differences in heart rates characteristic for these birds. PMID:5555579

Jewett, Paul H.; Sommer, J. R.; Johnson, E. A.

1971-01-01

443

Cardiac Aspergillosis  

Microsoft Academic Search

\\u000a Cardiac aspergillosis has been increasingly recognized as a complication of immunocompromise in recent times. The use of progressively\\u000a more potent immunosuppressive agents and the longer survival times of transplant recipients is likely contributing to an increasing\\u000a prevalence of the disease. Although still uncommon, the disease has an extremely high mortality rate and management remains\\u000a difficult. Cardiac aspergillosis can present as

Philippe Lagacé-Wiens; Ethan Rubinstein

444

Nuclear cardiac  

SciTech Connect

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

Slutsky, R.; Ashburn, W.L.

1982-01-01

445

Cardiac Applications for Human Pluripotent Stem Cells  

PubMed Central

Human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) can self-renew indefinitely, while maintaining the capacity to differentiate into useful somatic cell types, including cardiomyocytes. As such, these stem cell types represent an essentially inexhaustible source of committed human cardiomyocytes of potential use in cell-based cardiac therapies, high-throughput screening and safety testing of new drugs, and modeling human heart development. These stem cell-derived cardiomyocytes have an unambiguous cardiac phenotype and proliferate robustly both in vitro and in vivo. Recent transplantation studies in preclinical models have provided exciting proof-of-principle for their use in infarct repair and in the formation of a “biological pacemaker”. While these successes give reason for cautious optimism, major challenges remain to the successful application of hESCs (or hiPSCs) to cardiac repair, including the need for preparations of high cardiac purity, improved methods of delivery, and approaches to overcome immune rejection and other causes of graft cell death. In this review, we describe the phenotype of hESC- and hiPSC-derived cardiomyocytes, the state of preclinical transplantation studies with these cells, and potential approaches to overcome the aforementioned hurdles. PMID:19689350

Shiba, Yuji; Hauch, Kip D.; Laflamme, Michael A.

2010-01-01

446

Cardiac cephalgia.  

PubMed

"Cardiac cephalgia" is a type of secondary headache disorder, usually initiated by exertion that is related to myocardial ischemia. Primary exertional headaches such as sex-, cough-, or exercise-induced headaches are typically benign. Cardiac cephalgia, on the other hand, can have life-threatening complications. Due to overlapping features and similarities in presentation, cardiac cephalgia can be misdiagnosed as a primary headache disorder such as migraine. However, the management of these conditions is unique, and treatment of cardiac cephalgia with vasoconstrictors intended for migraine can potentially worsen myocardial ischemia. Thus, it is important to make the correct diagnosis by evaluating cardiac function with an electrocardiogram and/or stress testing. In this review, we examine reported cases of cardiac cephalgia from the past 5 years to highlight the importance of this condition in the differential diagnosis of a headache in a patient with a history of cardiovascular risk factors, as well as to discuss the appropriate approach to diagnosis and the proposed pathogenic mechanisms of this condition. PMID:25819974

Torres-Yaghi, Yasar; Salerian, Justin; Dougherty, Carrie

2015-04-01

447

The year in review of clinical cardiac electrophysiology.  

PubMed

This past year saw multiple important advances in the field clinical cardiac electrophysiology. Seminal articles describing new anticoagulant drugs for stroke prevention in atrial fibrillation were published. New results that raise questions regarding the safety of dronedarone and several new promising techniques in AF ablation were described. Important articles that refine our understanding of the risk of sudden death among Wolff-Parkinson-White patients were published. In the basic and translational sciences, the application of gene therapy to the study and potential treatment of arrhythmias was described, whereas genetic determinants important to the optimal treatment of inherited arrhythmia syndromes were further elucidated. Issues relevant to cardiac rhythm device therapy included investigations into the St. Jude Riata lead, new applications of device monitoring, predicting response to cardiac resynchronization therapy, and the use of pacemakers for vasovagal syncope. PMID:23312706

Marcus, Gregory M; Keung, Edmund; Scheinman, Melvin M

2013-02-19

448

History of cardiac rhythm disorders.  

PubMed

The history of cardiac rhythm disorders including antiarrhythmic drugs and electrotherapeutical tools is long and fascinating. In the beginning, there was not simply the anatomy and physiology of the heart, but also analysis of the pulse, which indicates the activity of the heart. Thus, like any other field of medicine, the study of arrhythmias has a distinctive past. Our current level of knowledge is not the result of a straight, linear progression any more than there is a static, established, monolithic body of thought dominating this field. Instead, our knowledge of arrhythmias today is the result of many competitive, sometimes serendipitous, scientific realizations, of which a few proved useful enough to pursue and eventually led to real advancements. Looking at the worldwide development of rhythmology it can be said that considerable contributions came from Germany in the last few centuries. Arrhythmology--past, present and future--includes clearly German investigators as pioneers of the field. The growing clinical importance of electric cardiac stimulation has been recognized and renewed as Zoll in 1952 described a successful resuscitation in cardiac standstill by external stimulation. The concept of a fully automatic implantable cardioverter-defibrillator system for recognition and treatment of ventricular flutter/fibrillation was first suggested in 1970. The first implantation of the device in a human being was performed in February 1980. By early 1997, 17 years after the first human implantation more than 100,000 ICD systems had been implanted worldwide. Further developments concern new pharmacological compounds, modern cardioverter-defibrillators, radiofrequency ablation, particularly pulmonary vein ablation in atrial fibrillation, innovative pacemakers including preventive pacing techniques, probably laser therapy and perhaps the automatic implantable pharmacological defibrillator. The advances in the field of therapeutic application of pharmacologic and electrical means as well as alternative methods will continue as rapidly as before in order to give us further significant aid in taking care of the patient. PMID:12436752

Lüderitz, B

2002-01-01

449

Endovascular extraction techniques for pacemaker and ICD lead extraction  

PubMed Central

In the last few years, comprehensive endovascular techniques have been developed to extract chronically implanted pacemaker and defibrillator leads. It is important that referring physician have knowledge of the advantages and limitations of the different techniques. In this paper we discuss the techniques and results of the currently used endovascular extraction techniques. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7 PMID:25696690

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

2001-01-01

450

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

451

Physiological effects of light on the human circadian pacemaker  

NASA Technical Reports Server (NTRS)

The physiology of the human circadian pacemaker and its influence and on the daily organization of sleep, endocrine and behavioral processes is an emerging interest in science and medicine. Understanding the development, organization and fundamental properties underlying the circadian timing system may provide insight for the application of circadian principles to the practice of clinical medicine, both diagnostically (interpretation of certain clinical tests are dependent on time of day) and therapeutically (certain pharmacological responses vary with the time of day). The light-dark cycle is the most powerful external influence acting upon the human circadian pacemaker. It has been shown that timed exposure to light can both synchronize and reset the phase of the circadian pacemaker in a predictable manner. The emergence of detectable circadian rhythmicity in the neonatal period is under investigation (as described elsewhere in this issue). Therefore, the pattern of light exposure provided in the neonatal intensive care setting has implications. One recent study identified differences in both amount of sleep time and weight gain in infants maintained in a neonatal intensive care environment that controlled the light-dark cycle. Unfortunately, neither circadian phase nor the time of day has been considered in most clinical investigations. Further studies with knowledge of principles characterizing the human circadian timing system, which governs a wide array of physiological processes, are required to integrate these findings with the practice of clinical medicine.

Shanahan, T. L.; Czeisler, C. A.

2000-01-01

452

Powering pacemakers from heartbeat vibrations using linear and nonlinear energy harvesters  

NASA Astrophysics Data System (ADS)

Linear and nonlinear piezoelectric devices are introduced to continuously recharge the batteries of the pacemakers by converting the vibrations from the heartbeats to electrical energy. The power requirement of a pacemaker is very low. However, after few years, patients require another surgical operation just to replace their pacemaker battery. Linear low frequency and nonlinear mono-stable and bi-stable energy harvesters are designed according to the especial signature of heart vibrations. The proposed energy harvesters are robust to variation of heart rate and can meet the power requirement of pacemakers.

Amin Karami, M.; Inman, Daniel J.

2012-01-01

453

Successful implantation of a dual-chamber pacemaker in an ELBW infant for long QT syndrome.  

PubMed

Long QT syndromes encompass the most prevalent group of ion channelopathies. Long QT syndromes are predominantly familial and predispose the affected individual to ventricular arrhythmias and sudden death. Permanent pacemaker insertion for long QT syndrome is discouraged apart from younger patients exhibiting 2:1 atrioventricular block. However, permanent pacemaker insertion is a relatively common procedure in neonates with atrioventricular block, and dual-chamber permanent pacemaker insertion in low birth weight infants is challenging. We describe the management of long QT syndrome - type 2 - presenting in an extremely preterm neonate including epicardial, dual-chamber permanent pacemaker insertion. PMID:24905882

McCrossan, Brian; d'Udekem, Yves; Davis, Andrew Mark; Pflaumer, Andreas

2015-03-01

454

Permanent Pacemaker Lead Induced Severe Tricuspid Regurgitation in Patient Undergoing Multiple Valve Surgery  

PubMed Central

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

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

2015-01-01

455

Lifetime cardiac reinterventions following the fontan procedure.  

PubMed

Patients with single ventricle physiology face significant morbidity and mortality following the Fontan procedure resulting in the need for additional cardiac reinterventions. Online patient education resources provide limited information on the reinterventions performed in single ventricle patients following the Fontan procedure. We sought to determine cardiac surgical and percutaneous reintervention rates and factors affecting reinterventions following the Fontan procedure. Databases from a single tertiary care center were retrospectively reviewed for all patients who underwent a Fontan procedure between 1978 and 2002. The number and type of cardiac surgical and percutaneous interventions following the Fontan procedure were determined, and relationships between need for reintervention and clinical variables were sought. A total of 91 patients (55 males) underwent the Fontan procedure at a median age of 5.50 years (IQR: 3.33-9.50 years). Median age at last follow-up, death, or transplant was 21.89 years (IQR: 10.87-25.51 years). Following the Fontan procedure, 60 (66%) patients required an additional 144 median sternotomies and 61 (67%) required 139 percutaneous cardiac interventions. Pacemaker system placement/replacement was the most common intervention following the Fontan procedure. The median time to first cardiac surgery following the Fontan was 1.96 years (IQR: 0.06-8.42 years) while the median time to the first percutaneous intervention was 7.63 years (IQR: 0.65-15.89 years). Families of single ventricle patients should be counseled on the likelihood of requiring additional cardiac interventions following the Fontan procedure. PMID:25135603

Van Dorn, Charlotte S; Menon, Shaji C; Johnson, Joyce T; Day, Ronald W; Hoffman, James L; Yetman, Anji T

2015-02-01

456

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

PubMed

As part of a 3-wk intersession workshop funded by a National Science Foundation Expeditions in Computing award, 15 undergraduate students from the City University of New York(1) collaborated on a study aimed at characterizing the voltage dynamics and arrhythmogenic behavior of cardiac cells for a broad range of physiologically relevant conditions using an in silico model. The primary goal of the workshop was to cultivate student interest in computational modeling and analysis of complex systems by introducing them through lectures and laboratory activities to current research in cardiac modeling and by engaging them in a hands-on research experience. The success of the workshop lay in the exposure of the students to active researchers and experts in their fields, the use of hands-on activities to communicate important concepts, active engagement of the students in research, and explanations of the significance of results as the students generated them. The workshop content addressed how spiral waves of electrical activity are initiated in the heart and how different parameter values affect the dynamics of these reentrant waves. Spiral waves are clinically associated with tachycardia, when the waves remain stable, and with fibrillation, when the waves exhibit breakup. All in silico experiments were conducted by simulating a mathematical model of cardiac cells on graphics processing units instead of the standard central processing units of desktop computers. This approach decreased the run time for each simulation to almost real time, thereby allowing the students to quickly analyze and characterize the simulated arrhythmias. Results from these simulations, as well as some of the background and methodology taught during the workshop, is presented in this article along with the programming code and the explanations of simulation results in an effort to allow other teachers and students to perform their own demonstrations, simulations, and studies. PMID:22139782

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

2011-12-01

457

Strength Training Guidelines for Cardiac Patients.  

ERIC Educational Resources Information Center

Provides practical guidelines for a strength training program for cardiac patients which may be modified to fit a particular program. The recommendations include criteria for admission, procedures for orientation and instruction, and techniques for supervision. (SM)

Sparling, Phillip B.; Cantwell, John D.

1989-01-01

458

Pacemaker Primary Curriculum; Lesson Book Level A.  

ERIC Educational Resources Information Center

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

Ross, Dorothea M.; Ross, Sheila A.

459

Pacemaker Primary Curriculum; Lesson Book Level D.  

ERIC Educational Resources Information Center

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

Ross, Dorothea M.; Ross, Sheila A.

460

Pacemaker Primary Curriculum; Lesson Book Level C.  

ERIC Educational Resources Information Center

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

Ross, Dorothea M.; Ross, Sheila A.

461

Pacemaker Primary Curriculum; Lesson Book Level B.  

ERIC Educational Resources Information Center

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

Ross, Dorothea M.; Ross, Sheila A.

462

Cardiac conditions.  

PubMed

Cardiovascular disease (CVD) is the leading cause of death in the US. The growth of the older population in coming decades will inevitably increase the incidence of age-related cardiac disease. Increasing evidence has shown the prevalence of co-morbid mental health conditions in CVD patients. Specifically, depression and anxiety have been linked with CVD mortality. Due to the risk of psychosocial conditions with cardiac patients, mental health practitioners in health and gerontology need to be well-informed about CVD-related mental health comorbidity and current research developments. Accordingly, this article provides a systematic review of the clinical evidence about the efficacy, cost-effectiveness, and any potential risk of psychosocial intervention with cardiac patients. PMID:18924386

Peck, Michel D; Ai, Amy L

2008-01-01

463

Heart Rate Reduction by Ivabradine Reduces Diastolic Dysfunction and Cardiac Fibrosis  

Microsoft Academic Search

Objectives: To determine if heart rate (HR) reduction with ivabradine (IVA), a selective inhibitor of the pacemaker If current, prevents cardiac dysfunction associated with dyslipidemia. Methods: New Zealand White rabbits received either a standard diet, a 0.5% cholesterol-enriched diet only (CD), or a 0.5% CD with IVA (17 mg\\/kg\\/day) for 12 weeks. HR, left ventricular (LV) systolic function, diastolic function

David Busseuil; Yanfen Shi; Mélanie Mecteau; Geneviève Brand; Marc-Antoine Gillis; Eric Thorin; Caroline Asselin; Philippe Roméo; Tack Ki Leung; Jean-Gilles Latour; Christine Des Rosiers; Muriel Bouly; Eric Rhéaume; Jean-Claude Tardif

2010-01-01

464

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

Microsoft Academic Search

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

D. Difrancesco; D. Noble

1985-01-01

465

Cardiac angiosarcoma.  

PubMed

Angiosarcoma is one of the most common cardiac tumors, but early detection of this tumor is often difficult, as exemplified by our patient, a 55-year-old woman whose cardiac tumor was first detected by echocardiography. Surgical removal of the tumor was impossible due to its extensive pericardial invasion. Pathological diagnosis was not complete before autopsy because of the wide occupied necrotized area of the tumor. There is no diagnostic imaging technique available to detect such a necrotized area. An imaging technique more powerful than echocardiography and able to diagnose angiosarcoma earlier is needed. PMID:8933189

Ohtahara, A; Hattori, K; Fukuki, M; Hirata, S; Ahmmed, G U; Kato, M; Fujimoto, Y; Shigemasa, C; Mashiba, H

1996-10-01

466

Cardiac rehabilitation I  

Microsoft Academic Search

Cardiovascular disease (CVD) is the leading cause of death and disability for women and men. There are gender differences in recovery from coronary events, which may be due physiological, sociodemographic, or psychosocial factors. Cardiac rehabilitation programs have beneficial effects on coronary recovery. The following presents a review of the literature from MedLine (1997–2001) and PsychInfo (1984–2001) on gender differences in

Sherry L. Grace; Susan E. Abbey; Zachary M. Shnek; Jane Irvine; Renée-Louise Franche; Donna E. Stewart

2002-01-01

467

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

PubMed

Pacemaker neurons with an intrinsic ability to generate rhythmic burst-firing have been characterized in lamina I of the neonatal spinal cord, where they are innervated by high-threshold sensory afferents. However, little is known about the output of these pacemakers, as the neuronal populations that are targeted by pacemaker axons have yet to be identified. The present study combines patch-clamp recordings in the intact neonatal rat spinal cord with tract-tracing to demonstrate that lamina I pacemaker neurons contact multiple spinal motor pathways during early life. Retrograde labeling of premotor interneurons with the trans-synaptic pseudorabies virus PRV-152 revealed the presence of burst-firing in PRV-infected lamina I neurons, thereby confirming that pacemakers are synaptically coupled to motor networks in the spinal ventral horn. Notably, two classes of pacemakers could be distinguished in lamina I based on cell size and the pattern of their axonal projections. Whereas small pacemaker neurons possessed ramified axons that contacted ipsilateral motor circuits, large pacemaker neurons had unbranched axons that crossed the midline and ascended rostrally in the contralateral white matter. Recordings from identified spino-parabrachial and spino-periaqueductal gray neurons indicated the presence of pacemaker activity within neonatal lamina I projection neurons. Overall, these results show that lamina I pacemakers are positioned to regulate both the level of activity in developing motor circuits and the ascending flow of nociceptive information to the brain, thus highlighting a potential role for pacemaker activity in the maturation of pain and sensorimotor networks in the central nervous system. J. Comp. Neurol. 523:1038-1053, 2015. © 2015 Wiley Periodicals, Inc. PMID:25380417

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

2015-05-01