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PubMed1988

Fundamental study on transcutaneous biotelemetry using diffused light.

A new method of biotelemetry is proposed, which realizes non-restrained acquisition of biological signals using infrared light diffused out from animal skin. This technique is fundamentally different from conventional telemetry techniques which use radiofrequency electromagnetic waves. An optical transmitter, which consists of some LEDs is implanted beneath the skin. Biological information such as an ECG signal is collected in vivo and the light emitted from the LEDs is modulated by the signal. The light transmitted through the skin is strongly diffused and spread out in a wide angle. The light is collected by remotely located optical receivers and biological information is obtained by demodulating the signal. Thus, the biological information in vivo is obtained without restraining the object with cables or optical fibers. In order to verify the possibility of the above techniques, a system which obtains an ECG from a laboratory animal has been developed. An infrared light was chosen because it is invisible, and has high transmittance through the skin. In addition, there are wide variety of light sources and detectors available in the range of near-infrared. Considering the stability of the communication link and the power consumption of the implanted transmitter, a PFM (pulse frequency modulation) technique was used. Using the system the transcutaneous ECG telemetry was successfully performed. In the experiment the indirect light, reflected and scattered by walls, a ceiling and a floor, was shown to be useful for optical telemetry. Light transmission patterns through the skin of a mouse were measured. The results suggest the possibility of telemetry even from the deep part of the body cavity. It is concluded that recent progress in optical and electronic technology has reached the point where transcutaneous optical telemetry of biological signals has become possible.

Animals↗

PubMedDate not supplied

The clinical assessment of cardiovascular emergencies.

Data are given for a 2-year study of fire department ambulance runs in Houston, Texas. Comparisons are made between those runs in which telemetry was used and those in which telemetry was not used. These data show an important relationship between the prognosis of patients who were recognized by emergency medical technicians as cardiac emergencies (and therefore received telemetry service) and those patients who were not identified as cardiac emergencies and did not receive telemetry service. Criteria used for clinical assessment and classification of emergencies are discussed. Emergency life-support systems with telemetry can have significant benefit for certain selected acute, recognizable cardiovascular emergencies, but the majority of ischemic heart disease fatalities do not appear to be deriving benefit from these systems.

Ambulances↗

PubMed2005

Are we appropriately triaging patients with unstable angina?

BACKGROUND: It is uncertain how aggressively patients should be monitored and admitted to the hospital for chest pain syndromes and if the monitoring itself affects patient care, process, or outcomes. We assessed the appropriateness of care based on retrospective analysis of admission bed assignment (nonmonitored vs monitored) and Thrombolysis in Myocardial Infarction (TIMI) risk score in patients from the Global Unstable Angina Registry and Treatment Evaluation (GUARANTEE) Registry. METHODS: Baseline characteristics, process of care, and outcomes were compared among 2939 patients admitted to 1 of 35 hospitals in the United States. Patients were stratified into low (0-2), intermediate (3 or 4), and high (5-7) risk based on TIMI risk score. RESULTS: Among the patients, 92 (3%) were admitted to the cardiac care unit (CCU), 1602 (56%) were admitted to the telemetry unit, and 1163 (41%) were admitted to an unmonitored bed. Paradoxically, high-risk patients comprised only 1% of those in the CCU, 5% of those in telemetry, and 10% of those in nonmonitored units. Conversely, low-risk patients were 64% of those in the CCU, 53% of those in telemetry, and 42% of those in unmonitored beds. Procedures were done more often on patients admitted to nonmonitored units than those on telemetry or in the CCU irrespective of TIMI risk score. CONCLUSIONS: This registry suggests that triage of patients does not routinely follow the risk-based approach suggested in the American College of Cardiology and American Heart Association guidelines and could therefore potentially lead to inefficiencies in care. Better implementation of risk stratification for acute coronary syndrome evaluation and management is necessary.

Aged↗

PubMed2001

The use of permanent pacemakers in the detection of cardiac arrhythmias.

AIMS: To compare pacemaker telemetry with simultaneous Holter recordings in the diagnosis of atrial fibrillation and to evaluate the STOP-AF study telemetry criteria for the presence of atrial fibrillation. METHODS AND RESULTS: 18 consecutive patients enrolled in the STOP-AF study had simultaneous 24 h Holter recordings and down-loaded pacemaker telemetry. There was good agreement on heart rate, but the STOP-AF pacemaker criteria achieved only 57% sensitivity with 64% specificity for the presence of atrial fibrillation on Holter recording over 24 h. False-positives appeared to result from far-field sensing while false-negatives occurred with very short episodes of atrial fibrillation. The pacemaker's antitachycardia responses were not specific for the presence of atrial fibrillation. CONCLUSION: Pacemaker telemetry is a potentially important source of data on cardiac arrhythmias. Further studies are required to define the limitations of these data in specific devices before they can be interpreted with confidence.

Arrhythmias, Cardiac↗

PubMed1992

[Telemetric cardiotocography--clinical value and limits of the method in routine monitoring].

Cardiotocography by external telemetry and maternal ambulation has been compared to the usual recording in recumbent position. The visual interpretation extended to several items, such as technical quality, CTG scoring, contractions and foetal activity, which were interpreted for single groups of gestational age and diagnosis. A questionnaire of the patients joined with this study, referring to the acceptance of cardiotocography, definitely voted for the telemetrical method. As to the valuation of the cardiotocograms (CTGs), it was necessary to consider a slight restriction of the undulation of the foetal heart rate by telemetry. Referring to the technical quality of the CTGs, the telemetrical method was inferior in all points while recording in recumbent position. Problems appeared to occur especially with adipose gravidas. In patients with toxaemia, we noticed a tendency to increasing systolic blood pressure combined with growing restriction of foetal undulation by telemetrical recording. The use of external telemetry with maternal ambulation at other diagnostical situations should depend only on technical quality and maternal acceptance of telemetry, since there are no differences with respect to information.

Adolescent↗

PubMedDate not supplied

[Telemedicine and cardiology].

INTRODUCTION: Telecommunications and information technology provide clinical care at distance by means of telemedicine. Hospitals and other health care facilities use medical telemetry devices for monitoring patients' vital signs. These portable devices are used for measuring patient vital signs such as ECG, blood pressure, heart rate, respiration, capnography (CO2) and other important parameters and then transmit these information to a remote location using a nearby receiver. APPLICATION OF TELEMETRY: Eliminating the need for wired connection with the patient, monitors allow, otherwise bedridden patients to be mobile, which shortens the recovery time. Wireless technology is also useful in the emergency care units, because emergency physicians need not leave their patients while consulting a handheld wireless device. This equipment also enables a paramedic to communicate with emergency physicians for early assessment, well before patients' arrive in hospital. TELEMEDICINE: Certain types of medical telemetry devices may be used in home conditions. Telemetry can provide monitoring and home health care services at distance, using advanced telecommunications and information technology in patients with reasonably stable, but a severe, chronic, difficult condition and caring home environment. This information can enable health-care providers to effectively manage treatment without need for acute emergency treatment and hospitalization. CONCLUSION: Hospitals worldwide are under constant pressure to decrease healthcare cost and to improve treatment outcome. Telemedicine and home health care may be one of the solutions for the problem.

Cardiology↗

PubMed2006

Non-invasive measurement of pan-colonic pressure over a whole digestive cycle: clinical applications of a capsule-style manometric system.

AIM: To study the prolonged colonic motility under normal conditions with a novel capsule-style micro-system and to assess its clinical significance. METHODS: A single use telemetry capsule (10 mm in diameter, 20 mm in length) embedded with a pressure sensor was ingested by the subjects. The sensor is capable of transmitting colonic pressure wirelessly for more than 130 h. The time of capsule entering the segmental colon was detected by ultrasound. The ultrasonic electrodes were mounted on the surface of the ileocecum and navel and at the junction of the left and rectosigmoid colon of the subjects in sequence, which were identified by abdominal X-rays with radiopaque markers. To verify the accuracy and reliability of ultrasonic detection of telemetry capsules at key points of colon, the segmental colonic transit time was simultaneously recorded by using radiopaque markers. RESULTS: The signal lamp showed that all recorders could receive the radio signal transmitted by the telemetry capsule. The X-rays showed that all telemetry capsules were detected successfully when they were passing through the key points of colon. There was a significant correlation between the transit results obtained by ultrasonic detection or by radiopaque markers. Colorectal recording was obtained from 20 healthy subjects during 613 h (411 h during waking, 202 h during sleep). Compared to waking, the number of pressure contractions and the area under pressure contractions were significantly (P < 0.05) decreased during sleep (21 +/- 5 h(-1) vs 15 +/- 4 h(-1), 463 +/- 54 mmHg x s/min vs 342 +/- 45 mmHg x s/min). The colonic motility exhibited significant regional variations both in the circadian behavior and in response to waking and meal. CONCLUSION: The capsule-style micro-system is reliable and noninvasive, and may represent a useful tool for the study of physiology and pathology of colonic motor disorders.

Adult↗

PubMed1996

Acute effects of radiofrequency ablation of atrial arrhythmias on implanted permanent pacing systems.

We studied the safety of performing RF catheter ablation in patients with implanted permanent pacemakers by monitoring the function of implanted pacing systems before, during, and immediately after exposure to RF energy. Patients with implanted pacing systems may require RF ablation for treatment of a variety of tachyarrhythmias. High frequency electromagnetic fields, such as RF energy, may affect implanted pacing systems, causing temporary or permanent loss of output, undersensing, oversensing, asynchronous pacing, or reversion to "reset" (Recommended Replacement Time or Power On Reset) parameters. Thirty-five patients with implanted pacing systems (23 DDDR, 6 VVIR, 5 DDD, 1 VVI, 31 bipolar and 4 unipolar) underwent RF catheter ablation. Prior to ablation, each pacing system underwent measurements of pacing and sensing thresholds, telemetry of intracardiac electrograms and measurement of battery voltage and lead impedance(s). During ablation, pacemaker function was monitored by real-time telemetry, intracardiac electrograms, and surface ECG. Immediately after ablation, each pacing system was reevaluated. Telemetry during RF ablation revealed normal pacing and sensing in 14 (40%) of 35 patients. Refractory period extension with asynchronous pacing and noise mode reversion were seen in 16 (46%) of 35 patients. Rare under- and/or oversensing, reversion to reset parameters, and telemetry "lock up" with inhibition of pacing output was seen in a few patients. After ablation, there were no significant changes in atrial or ventricular pacing or sensing thresholds or measurements of atrial and ventricular lead impedances. We conclude that most permanent pacemakers are not adversely affected by exposure to RF energy during catheter ablation. A variety of pacemaker behaviors may be seen during RF ablation, and a thorough understanding of each pulse generator's potential response(s) to electromagnetic interference is important before undertaking catheter ablation in patients with permanent pacemakers. Careful reevaluation of the patient's pacing system following the procedure is mandatory.

Adult↗

PubMed1980

Effect of elicitation variables on analysis of language samples for normal and language-disordered children.

To evaluate the effect of elicitation stimuli and situations, expressive language samples were obtained from 10 normal children and 10 language-disordered children in four location-stimulus combinations and from wireless radio telemetry. These language samples were analyzed using the procedures of Developmental Sentence Scoring, Mean Length of Utterance, and inflectional scoring. No differences existed between the locations of home and clinic, but significant differences were noted among samples elicited using pictures as oppossed to open-ended questions as compared to telemetry samples. Normal and language-disordered children responded differently to these elicitation variables. Open-ended questions and telemetry yielded the highest performances on Developmental Sentence Scoring and inflectional scoring. Telemetry samples yielded the shortest response lengths. The two groups of children also responded differently in the specific scoring categories.

Child↗

PubMed1994

Validation of the CSA accelerometer for assessing children's physical activity.

The Computer Science Application (CSA) accelerometer is designed to detect the acceleration and deceleration of human movement. The purpose of this study was to evaluate its validity and utility for measuring children's activity in field settings. The criterion measure was heart rate telemetry. This study also examined the between-day stability of children's physical activity. Thirty-one children (7-15 yr) wore a CSA accelerometer and a heart rate telemetry monitor for 12 h.d-1 for 3 consecutive days. The validity correlation coefficients between accelerometry and heart rate telemetry for each monitored day ranged from r = 0.50-0.74. All children reported the accelerometer to be comfortable to wear. The moderate to high validity correlations and the subjects' favorable response to wearing the accelerometer support its validity and utility as an objective method for monitoring activity in children in field settings. However, the between-day stability of individual physical activity measures was low to moderate (r = -0.23 to 0.53), indicating that when using accelerometry or heart rate telemetry more than 3 d of monitoring is needed to assess usual activity.

Adolescent↗

PubMed1998

Effects of radio transmitter weight on a small nocturnal primate.

An increasing number of primatologists have begun using radio telemetry to study the behavioral ecology of nocturnal prosimian primates. Radio telemetry has enabled the collection of data on these nocturnal and cryptic prosimians that was previously difficult or impossible to otherwise obtain. A critical assumption of studies employing radio telemetry is that the radio transmitters have no appreciable negative effects on the study animals and the data being collected are not being biased by the presence of radio transmitters. This assumption is made because comparable data from a non-radio-collared control group are impossible to obtain. In an attempt to determine the tolerable weight limit for radio collars for a small nocturnal primate, the spectral tarsier, Tarsius spectrum, a comparison of the behavior and body weight of individuals wearing collars of two different weights was conducted. This study was conducted in Tangkoko Dua Saudara Nature Reserve in Sulawesi, Indonesia. A total of 16 individuals from seven groups were trapped in mist nets, radio-collared, and observed using focal follow sampling between April 1994 and June 1995. Each individual was observed for 4-6 months depending on the life span of the radio-collar battery. The two radiocollar weights appeared not to affect spectral tarsiers differentially. Average body masses in neither set of subjects differed between the days collars were attached and 6 months later, when they were removed. No differences in activity patterns, home range size, or prey capture rate were detectable between subjects wearing the different transmitters. These results suggest that the heavier radio collars used in this study did not have any appreciable effects on the behavioral patterns of this primate.

Animals↗

PubMed2007

Non-invasive restrained ECG recording in conscious small rodents: a new tool for cardiac electrical activity investigation.

In vivo electrophysiology remains a suitable method to monitor cardiac activity; however, surface electrocardiogram (ECG) monitoring remains complicated in the case of small animals. Sedation has helped to maintain the animal still; however, it is known that anesthetic drugs impair the regulation of the cardiac electrical activity. To circumvent this problem, ECG monitoring using telemetry or restraints has been developed. This study reports a new methodology, based on a restraining system without further sedation, for recording ECGs on small animal models. We investigated its efficacy in Syrian hamsters and in several strains of mice, and we compared these data to those obtained with telemetry devices. We show that this new system can easily be used in animals of different sizes ranging from adult hamsters to newborn mice. When compared to telemetry, this restrained ECG monitoring method shows a very good yield, as 65% of total beats can be used for further analysis. When recorded in the same animals, RR intervals distributions are identical for both techniques. In conclusion, this restrained ECG monitoring technique is a well-suited tool for exploring various aspects of cardiac electrophysiology in a wide variety of small animals including very young mice.

Animals↗

PubMed1987

Utility of ambulatory electrocardiography in detecting pacemaker dysfunction in the early postimplantation period.

The value of ambulatory electrocardiography (AECG) in detecting pacemaker dysfunction before hospital discharge was assessed in 100 patients a mean of 1.2 days after pacemaker implantation. The incidence of permanent pacemaker dysfunction detected by AECG in the early postimplantation period, the frequency that pacemaker dysfunction detected by AECG was not detected by telemetric monitoring and the frequency that results of AECG led to pacemaker reprogramming before hospital discharge were determined. AECG detected at least 1 type of pacemaker dysfunction in 35% of patients and routine telemetry identified the abnormality in only 8% (p less than 0.001). Pacemaker dysfunction occurred in 42% of patients with dual-chamber devices and 27% of those with single-chamber devices (difference not significant). In the 35 patients who had pacemaker malfunction, a total of 50 instances of pacemaker dysfunction were detected. Failure of atrial capture occurred in 2% of patients, failure of atrial sensing in 9%, failure of atrial output in 1%, failure of ventricular capture in 8%, failure of ventricular sensing in 14%, failure of ventricular output due to myopotential inhibition in 11% and pacemaker-mediated tachycardia in 5%. The results of the AECG led to a clinical intervention in 22 patients (pacemaker reprogramming in 21 patients and lead repositioning in 1 patient) in whom no pacemaker dysfunction was suspected on the basis of telemetry or clinical symptoms. In conclusion, AECG provides additional benefit beyond that of routine telemetry monitoring in identifying pacemaker dysfunction in the early period after implantation.

Aged↗

PubMed1982

Use of radiotelemetry to obtain expressive language samples.

Expressive language samples were obtained from normal and language-disordered children through standard interview procedures and through wireless radiotelemetry. Comparisons of these samples using Developmental Sentence Scoring (DSS), mean length of utterance (MLU), and inflectional scoring indicated significant differences between the groups of children, and among the interview-telemetry samples. Telemetry samples yielded different overall scores from those obtained with the interview samples, and there were significant differences in the types of language performance within the samples. Reliable telemetry scores across days were obtained. Difficulties in using the equipment are described and the procedures are compared.

Child↗

PubMed1996

Patient monitoring system for load measurement with spinal fixation devices.

Fractures of the spine can be stabilized by different implants. Their stiffness varies widely and only little is known about the loads acting on these devices. In order to measure the forces and moments in the implant, the internal fixator after Dick was modified. An inductively powered telemetry unit is placed inside the fixator and is hermetically sealed against body fluids. An integrated eight channel telemetry chip was developed to measure the signals of six strain gauge sensors, the implant temperature and the power supply. Because two fixators are implanted together, two telemetry transmitters run at the same time. This paper describes the function of the instrumented implant and the external system components.

Biomechanical Phenomena↗

PubMed2004

Serotonin 2A receptors modulate tail-skin temperature in two rodent models of estrogen deficiency-related thermoregulatory dysfunction.

Menopause-associated thermoregulatory dysfunction, including hot flushes and night sweats, is effectively treated by hormonal therapies that include estrogens. Evidence suggests that estrogen regulates serotonin 2A (5-HT(2A)) receptor expression and that 5-HT(2A) receptors are involved in thermoregulation. Therefore, the role of 5-HT(2A) receptors in thermoregulation was assessed in two rat models of ovariectomy-induced thermoregulatory dysfunction. The first model is based on measurement of the tail-skin temperature (TST) increase following naloxone-induced withdrawal in morphine-dependent ovariectomized (OVX) rats (MD model), while the second model relies on telemetric assessment of diurnal TST changes in ovariectomized rats (telemetry model). Treatment with a 5-HT(2A/2C) receptor agonist, (-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI), prevented the naloxone-induced TST increase in the MD model and restored normal active-phase TST in the telemetry model. The selective 5-HT(2A) receptor antagonist, MDL-100907, had no effect on the naloxone-induced flush when administered alone in the MD model, but it decreased DOI's ability to abate the flush. In the telemetry model, MDL-100907 attenuated the DOI-induced decrease in active-phase TST. Interestingly, MDL-100907 increased TST in both models when given alone, with the TST increase occurring prior to the naloxone-induced flush in the MD model. To evaluate the role of central nervous system (CNS) 5-HT(2A) receptors in TST regulation, DOI was administered in combination with a known peripheral 5-HT(2A/2C) receptor antagonist, xylamidine, in the MD model. Xylamidine had no effect on DOI's ability to abate the naloxone-induced flush. These results indicate that activation of central 5-HT(2A) receptors restores temperature regulation in two rodent models of ovariectomy-induced thermoregulatory dysfunction.

Amidines↗

PubMed1999

Hip endoprosthesis for in vivo measurement of joint force and temperature.

Friction between the prosthetic head and acetabular cup increases the temperature in hip implants during activities like walking. A hip endoprosthesis was instrumented with sensors to measure the joint contact forces and the temperature distribution along the entire length of the titanium implant. Sensors and two inductively powered telemetry units are placed inside the hip implant and hermetically sealed against body fluids. Each telemetry unit contains an integrated 8-channel telemetry chip and a radio frequency transmitter. Force, temperature and power supply data are transmitted at different frequencies by two antennas to an external twin receiver. The inductive power supply is controlled by a personal computer. Force and temperature are monitored in real time and all data are stored on a video tape together with the patient's images. This paper describes the design and accuracy of the instrumented implant and the principal function of the external system components.

Body Temperature↗

PubMed1994

Power spectral analysis of heart rate variability as a new method for assessing autonomic activity in the rat.

The authors studied power spectral analysis of heart rate variability in the rat, hypothesizing that the quantitative information provided by this analysis reflects the interaction between sympathetic and parasympathetic regulatory activities. For this purpose, an electrocardiogram was recorded from conscious and unrestrained Wistar rats (Nippon, Shizuoka) (12-16 weeks old) by a telemetry system and analyzed by a power spectrum. Because it was thought that the electrocardiogram recorded by the telemetry system could provide more reliable data to assess autonomic nervous activity than the tethering system, the telemetry recording system was used. There were two major spectral components in the power spectrum at low frequency (LF) (0.6 Hz) and high frequency (HF) (approximately 1.4 Hz). On the basis of these data, the authors defined two frequency bands of interest: LF (0.04-1.0 Hz) and HF (1.0-3.0 Hz). The power of LF was higher than that of HF in the normal rat. Atropine (2 mg/kg intraperitoneally) significantly reduced both HF and LF power. Propranolol (4 mg/kg intraperitoneally) also significantly reduced LF power; however, it had no significant effect on HF power. Thus, this study in the rat confirmed earlier observations in the conscious dog and human. Furthermore, the decrease in the parasympathetic mechanism produced by atropine was reflected by a slight increase in the LF/HF ratio. The LF/HF ratio appeared to follow the reductions of sympathetic activity produced by propranolol. From these results, the LF/HF ratio seemed to be a convenient index of parasympathetic and sympathetic interactions in the rat.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗