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Copyright of Bulletin of Engineering Geology & the Environment is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of Engineering Geology & the Environment is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of Engineering Geology & the Environment is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The quality assessment of watercourse, located in a highly urbanized area was the goal of research. The SłuŻewiecki Stream, which flows in the southern part of the capital city of Warsaw is the subject of study. The aim of the research was to determine the tendency of the water quality changes in the SłuŻewiecki Stream, flowing in the highly urbanized area and being a sink of the non-point and industry sources of pollutions as well as the surface runoffs which comes from its catchment. The field research was conducted along the entire length of the stream in 2015 and 2016. The water samples were collected monthly from a depth to 20 cm. Water quality tests were carried out in accordance with the valid analytical methods. The obtained results point to poor water quality. Therefore it can be conducted that the development and use of the direct catchment is the one of main factors affecting the water quality in SłuŻewiecki Stream. The tributaries, often not inventoried, from built-up, populated areas, are the most polluted. Tributaries contain large amount of organic compounds and nutrients.

Objectives: To retrospectively investigate the reliability of the age-based formula, year/4 + 3.5 mm in predicting size and year/2 + 12 cm in predicting insertion depth of preformed endotracheal tubes in children and correlate these data with the body mass index., Patients and Methods: Patients were classified into 4 groups according to their nutritional status: thinness, normal weight, overweight, and obesity; we then retrospectively compared the actual size of endotracheal tube and insertion depth to the predicting age-based formula and to the respective bend-to-tip distance of the used preformed tubes., Results: Altogether, 300 patients were included. The actual endotracheal tube size corresponded with the Motoyama formula (64.7%, 90% CI: 60.0-69.1), except for thin patients, where the calculated size was too large (0.5 mm). The insertion depth could be predicted within the range of the bend-to-tip distance and age-based formula in 85.0% (90% CI: 81.3-88.0) of patients., Conclusion: Prediction of the size of cuffed preformed endotracheal tubes using the formula of Motoyama was accurate in most patients, except in thin patients (body mass index < -2 SD). The insertion depth of the tubes was mostly in the range of the age-based-formula to the bend-to-tip distance.

Objectives: To investigate differences in workplace exposure, demographic and clinical findings in engineered stone (ES) workers from a multinational consortium using the Engineered Stone Silicosis Investigators (ESSI) Global Silicosis Registry., Methods: With ethics board approval in Israel, Spain, Australia and the USA, ES workers ages 18+ with a physician diagnosis of work-related silicosis were enrolled. Demographic, occupational, radiologic, pulmonary function and silica-related comorbidity data were compared cross-sectionally among countries using analysis of variance, Fisher's exact tests and logistic regression., Results: Among 169 ES workers with silicosis, most were men, with mean age 51.7 (±11.4) years. Mean work tenure in stone fabrication or masonry was 19.9 (±9.8) years. Different methods of case ascertainment explained some inter-country differences, for example, workers in Queensland, Australia with a state-based surveillance program were likely to be identified earlier and with shorter work tenure. Overall, 32.5% of workers had progressive massive fibrosis, the most severe form of dust-related pneumoconiosis, of whom 18.5% reported ≤10 years of work tenure. Lung function impairment including restriction, reduced diffusion capacity and hypoxaemia was common, as was autoimmunity., Conclusions: Findings from a multinational registry represent a unique effort to compare demographic, exposure and clinical information from ES workers with silicosis, and suggest a substantial emerging population of workers worldwide with severe and irreversible silica-associated diseases. This younger worker population is at high risk for disease progression, multiple comorbidities and severe disability. The ESSI registry provides an ongoing framework for investigating epidemiological trends and developing prospective studies for prevention and treatment of these workers., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Benzoxonium chloride belongs to the group of quaternary ammonium salts, which have been widely used for decades as disinfectants because of their high efficacy, low toxicity, and thermal stability. In this study, we have prepared the C 10 -C 18 set of benzoxonium-like salts to evaluate the effect of their chemical and biological decontamination capabilities. In particular, biocidal activity against a panel of bacterial strains including Staphylococcus aureus in biofilm form was screened. In addition, the most promising compounds were successfully tested against Francisella tularensis as a representative of potential biological warfare agents. From a point of view of chemical warfare protection, the efficiency of BOC-like compounds to degrade the organophosphate simulant fenitrothion was examined. Notwithstanding that no single compound with universal effectiveness was identified, a mixture of only two compounds from this group would be able to satisfactorily cover the proposed decontamination spectrum. In addition, the compounds were evaluated for their cytotoxicity as a basic safety parameter for potential use in practice. In summary, the dual effect on chemical and biological agents of benzoxonium-like salts offer attractive potential as active components of decontamination mixtures in the case of a terrorist threat or chemical or biological accidents.

(1) Background-Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a multifaceted illness characterized by profound and persistent fatigue unrelieved by rest along with a range of other debilitating symptoms. Experiences of unrefreshing and disturbed sleep are frequently described by ME/CFS patients. This is the first systematic review assessing sleep characteristics in ME/CFS. The aim of this review is to determine whether there are clinical characteristics of sleep in ME/CFS patients compared to healthy controls using objective measures such as polysomnography and multiple sleep latency testing. (2) Methods-the following databases-Pubmed, Embase, Medline (EBSCO host) and Web of Science, were systematically searched for journal articles published between January 1994 to 19 February 2021. Articles that referred to polysomnography or multiple sleep latency testing and ME/CFS patients were selected, and further refined through use of specific inclusion and exclusion criteria. Quality and bias were measured using the Joanna Briggs Institute checklist. (3) Results-twenty observational studies were included in this review. The studies investigated objective measures of sleep quality in ME/CFS. Subjective measures including perceived sleep quality and other quality of life factors were also described. (4) Conclusions-Many of the parameters measured including slow- wave sleep, apnea- hypopnea index, spectral activity and multiple sleep latency testing were inconsistent across the studies. The available research on sleep quality in ME/CFS was also limited by recruitment decisions, confounding factors, small sample sizes and non-replicated findings. Future well-designed studies are required to understand sleep quality in ME/CFS patients.

Background: The quality of patients' recovery following surgery and anesthesia has been a matter of focus and concern over the past decade. The Quality of Recovery-40 (QoR-40) questionnaire was developed and validated for post-anesthesia patient evaluation. The QoR-40, however, is English-based and was tested and validated in Caucasian patients, a population that is culturally and behaviorally different from the Thai population. The objective of this study was to translate and modify the original English-language QoR-40 into the Thai language and evaluate the Quality of Recovery-35 Thai version for measuring health outcomes in Thai patients after surgery and anesthesia., Methods: Translation was performed according to internationally recognized translation standards to ensure the integrity of the translated version. Consistent with the recommendations of 25 anesthesiologists, five questions from the original QoR-40 were excluded. The 35-item questionnaire was then translated into the Thai language and renamed the Quality of Recovery-35 Thai version (Thai QoR-35). Overall, 43 outpatients and 53 inpatients rated their health and recovery status using three patient evaluation tools: 100-mm Visual Analogue Scale-Recovery (VAS-R), six-item Activities of Daily Living (ADL) questionnaire, and Thai QoR-35., Results: Overall, 90 % of patients took <10 min to complete the Thai QoR-35 questionnaire. The Thai QoR-35 and VAS-R showed good convergent validity (r = 0.84, P < 0.001). Discrimination validity was supported by a significant difference in mean scores for recovery among the Thai QoR-35, VAS-R, and ADL when compared between outpatients and inpatients (P < 0.01) and also between baseline and postoperative values (P < 0.001). The Thai QoR-35 also demonstrated good reliability with high internal consistency at three time points (Cronbach's alpha = 0.88, 0.89, 0.91, respectively; P < 0.01) and a split-half reliability coefficient of 0.65 (P < 0.001)., Conclusion: Thai QoR-35 is a valid, reliable tool for evaluating quality of recovery in Thai patients.

We extracted nucleotide sequences from the EMBL database that flank dinucleotide microsatellites in the long sequenced parts of the human, mouse and drosophila genomes. Comparison of the flanking sequences showed that the microsatellites were mostly connected to the bulk of genomic DNA through conserved, highly non-random and mostly (A+T)-rich sequences having many dozens of nucleotides in length. In many cases, the connectors were mutated versions of the flanked microsatellites whose sequence pattern gradually vanished with the distance from the microsatellite center. Hence many microsatellites have hundreds rather than dozens of nucleotides in length, and their ends are diffuse. In contrast, some microsatellites containing predominantly C and/or G, did not influence their neighborhood at all. These results make us change notions about the microsatellite nature. They also indicate that the microsatellites are the dominant part of eukaryotic genomes.

Monomolecular layers of the largest light-harvesting pigment-protein complex of Photosystem II (LHCII) were formed at the argon-water interface. The molecular area of the LHCII monomer in monomolecular layers determined from the isotherms of compression is found to be close to 14 nm2, which corresponds well to the molecular dimensions of the protein evaluated on the basis of crystallographic studies. Monolayers of LHCII were deposited on a glass support by means of the Langmuir-Blodgett technique and subjected to spectroscopic studies: electronic absorption spectrophotometry and spectrofluorometry. The fluorescence excitation spectra of chlorophyll a in monolayers of LHCII were analysed using gaussian deconvolution. Comparison of the absorption and fluorescence excitation spectra enabled calculation of the rate of excitation energy transfer in the system. Excitation energy was found to be transferred to chlorophyll a from chlorophyll b with 97% efficiency, from neoxanthin with 85%, from lutein with 62% and from violaxanthin with at least 54% efficiency. The analysis of the position of the 0-0 absorption band of the xanthophylls revealed that neoxanthin is located in the same protein environment as lutein but in a different environment than violaxanthin. The analysis of fluorescence excitation spectra of chlorophyll a in LHCII, recorded with the excitation light beam polarised in two orthogonal directions, enabled the determination of the mean orientation angle of the accessory xanthophyll pigments with respect to the plane of the sample. The mean orientation of lutein found in this study (approx. 51 degrees ) corresponds well to the crystallographic data. Neoxanthin was found to adopt a similar orientation to lutein. The transition dipole moment of violaxanthin was found to form a mean angle of 71 degrees with the axis spanning two polar regions of the protein, perpendicular to the plane of the monolayer, suggesting planar orientation of this pigment with respect to the plane of the thylakoid membrane. These experimentally determined xanthophyll orientations are discussed in terms of importance of peripheral xanthophyll pigments in supramolecular organisation of LHCII and the operation of the xanthophyll cycle within the thylakoid membrane.

Waveform parameters may affect the efficacy of ventricular defibrillation. Certain biphasic pulse waveforms are more effective for ventricular defibrillation than monophasic waveforms, but the optimal biphasic waveform parameters have not been identified. The purpose of this study was to investigate the effects of total pulse duration and the duration of the second (negative) phase on voltage and energy defibrillation requirements using biphasic waveforms. Defibrillation efficacy was evaluated in an isolated rabbit heart model using the Langendorff technique. The biphasic waveform was a truncated exponential with the initial voltage of the second phase equal to 50% of the final voltage of the first phase. An up/down protocol was used to determine the 50% probability-of-success levels (E50) for delivered energy and initial voltage. First, using pulse waveforms with equal positive and negative phase durations, test waveforms with total durations of 4 ms (2 ms positive + 2 ms negative), 6 ms (3 + 3 ms), and 16 ms (8 + 8 ms) were compared to the control waveform of 8 ms (4 + 4 ms) in 30 experiments. Defibrillation voltage requirements with 4 ms (174 +/- 56 V) were higher (P = 0.001) compared to 8 ms (127 +/- 49 V). Defibrillation voltage requirements for the 6-ms and 16-ms waveforms were similar to the 8-ms control waveform. Delivered energies tended to be higher with the 4-ms waveform. A second series of 40 experiments were performed to compare monophasic (4 + 0 ms) and three asymmetric biphasic waveforms (4 + 2 ms, 4 + 8 ms, and 4 + 16 ms) to the symmetric control waveform (4 + 4 ms). The monophasic (2.15 +/- 1.21 J) and the 4 + 16 ms waveform (1.86 +/- 1.09 J) required higher energies (P < or = 0.05) than the control waveform (1.24 +/- 0.41 J and 0.87 +/- 0.7 J, respectively). The monophasic waveform also resulted in greater voltage requirements (223 +/- 64 V) compared to the control waveform (160 +/- 26 V) (P = 0.02). Energy and voltage requirements were similar for the 4 + 2 ms and 4 + 8 ms waveforms compared to the control. Defibrillation requirements with biphasic waveforms were affected by total and second phase duration. For waveforms with equal phase durations, total durations between 6-16 ms resulted in the lowest values for defibrillation. For waveforms with variable second (negative) phase durations, durations ranging from 50%-200% of the first phase did not affect defibrillation efficacy.

Activity controlled pacemakers are the most widely used rate adaptive systems. We studied second-generation activity controlled systems (accelerometer) in 21 patients with such an accelerometer controlled system implanted during walking level and stairs. We compared them to the rate of vibration controlled, first-generation activity pacemakers and to the sinus rate of a healthy control group. A metronome directed the speed during walking and climbing stairs at 92, 108, and 120 steps/min. At 92 steps/min, the new accelerometer controlled systems showed a significant (P < or = 0.001) pacing rate increase from 107 +/- 8 beats/min during walking level to 124 +/- 8 beats/min during climbing stairs, and a significant decrease to 105 +/- 12 beats/min during walking downstairs. In contrast, first-generation activity controlled pacemakers showed a less physiological rate behavior with higher pacing rate (113 +/- 7 beats/min) walking downstairs than walking upstairs (97 +/- 9). For everyday activities at normal walking speed, accelerometer controlled pacemakers show a more physiological rate behavior than first-generation pacemakers, but they lose this physiological response with faster walking.

Objective: More than half of the pacemaker systems now being implanted can be rate adaptively paced. Our objective was to determine which patients benefit from rate-adaptive pacing in terms of improvement in maximum performance and aerobic capacity., Methods: Thirty patients with implanted accelerometer-driven, rate-adaptive pacemakers underwent a standardized, ergospirometrically and maximally symptoms = limited cardiopulmonary exercise (CPX) stress test with both rate-adaptive and fixed-rate stimulation in a randomized order. The patients were divided into three groups depending on the intrinsic heart rate achieved during maximum workload: group 1 achieved < or = 90 beats per minute (bpm), group 2 achieved 90 to < or = 110 bpm, and group 3 achieved > 110 bpm., Results: Group 1 demonstrated a significant increase (p < or = 0.01) in maximum oxygen uptake from 16.4 +/- 5.6 mL/kg/min with fixed-rate pacing to 23.2 +/- 11.1 mL/kg/min (+ 41.5%) with rate-adaptive pacing. At the anaerobic threshold, oxygen uptake significantly increased (p < or = 0.01) from 11.8 +/- 2.7 mL/kg/min to 15.7 +/- 5 mL/kg/min (+33.1%). Group 2 patients showed an increase in maximum oxygen uptake from 23.3 +/- 5.4 mL/kg/min to 25.3 +/- 4.9 mL/kg/min (+8.5%, p < or = 0.05) as well as an increase in oxygen uptake at the anaerobic threshold from 15.9 +/- 2.6 mL/kg/min to 18.1 +/- 2.9 mL/kg/min (+13.8%, p < or = 0.05) with rate-adaptive pacing. Group 3 demonstrated no significant difference between the two pacing methods (from 25.6 +/- 9.4 mL/kg/min to 25.9 +/- 9.3 mL/kg/min and from 15.8 +/- 5.5 mL/kg/min to 16.3 +/- 6 mL/kg/min). No difference in maximum oxygen uptake and in oxygen uptake at the anaerobic threshold was evident among the three groups when paced rate adaptively (not significant)., Conclusion: The second-generation, accelerometer controlled rate-adaptive pacemakers used in testing enabled a stress-oriented heart rate increase and an age- and gender-dependent adequate matching of maximum performance. The benefit from a rate-adaptive system to the patient increases as his or her chronotropic reserve limitation became more pronounced.

More than half of all pacemaker systems currently implanted function rate-adaptively. Our objective was to determine which patients benefit from rate-adaptive pacing in terms of improvement in maximum performance and aerobic capacity. Thirty patients with implanted accelerometer-driven, rate-adaptive pacemakers were examined ergospirometrically and patient symptom-limited while walking on a treadmill. The patients were divided into three groups depending on the intrinsic heart rate achieved during maximum workload: Group I achieved < or = 90 bpm, Group II achieved 90 to < or = 110 bpm, Group III achieved > 110 bpm. Group I demonstrated a significant increase (p < or = 0.01) in maximum oxygen uptake from 16.4 +/- 5.6 ml/kg/min with fixed-rate pacing to 23.2 +/- 11.1 ml/kg/min (+41.5%) with rate-adaptive pacing. At the anaerobic threshold, oxygen uptake significantly increased (p < or = 0.01) from 11.8 +/- 2.7 ml/kg/min to 15.7 +/- 5 ml/kg/min (+33.1%). Group II showed an increase in maximum oxygen uptake from 23.3 +/- 5.4 ml/kg/min to 25.3 +/- 4.9 ml/kg/min (+8.5%, p < or = 0.05) as well as an increase in oxygen uptake at the anaerobic threshold from 15.9 +/- 2.6 ml/kg/min to 18.1 +/- 2.9 ml/kg/min (+13.8%, p < or = 0.05) with rate-adaptive pacing. Group III demonstrated no significant difference between the two pacing methods (from 25.6 +/- 9.4 ml/kg/min to 25.9 +/- 9.3 ml/kg/min and from 15.8 +/- 5.5 ml/kg/min to 16.3 +/- 6 ml/kg/min). No difference in maximum oxygen uptake and in oxygen uptake at the anaerobic threshold was evident between the three groups when paced rate-adaptively (n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)

New activity pacemaker systems with the principle of sensing low-frequency acceleration in the anterior-posterior axis are currently under clinical evaluation. We compared the pacemaker system Relay, which represents this new generation of accelerometer controlled devices, with conventional activity systems sensing pressure and vibration. Ten pacemaker patients with implanted Activitrax, Sensolog or Relay pacemakers and 10 healthy volunteers with externally strapped-on pacemakers were studied. The aim was to evaluate the systems' ability to distinguish different workloads during graded treadmill testing with changes in speed and/or slope. The rate adaption of the new acceleration sensing pacemakers was found to be more adequate compared to vibration and pressure-sensing pacemakers when only the slope of the treadmill was varied. The acceleration-sensing pacemaker adjusted its rate according to the workload largely independent from the type of stress (n.s.). With the vibration and pressure-sensing pacemakers, however, significant differences (p < 0.05) were seen between rate adaption in the two stress test modes. The new generation of acceleration-sensing pacemakers has certain advantages over conventional vibration-sensitive systems in terms of a higher sensitivity to varying workloads and higher specificity to the type of exercise performed.

Activity-guided rate-adaptive pacing is currently the most widely used principle for rate adaptation. Broad experience has been gathered from several hundred thousand pacemakers that adjust the pacing rate according to vibrational forces detected by a piezosensor bonded to the inner side of the pacemaker can. A new generation of accelerometer-based pacemakers has been introduced into clinical practice. The vibrational type detects vibration, pressure, and shock waves traveling through the body with physical stress and using the pacemaker can as a resonator. In contrast, the accelerometer is insulated from the pacemaker housing and is incorporated into electronic hybrid circuitry. The forces detected by an accelerometer are motion and acceleration of the body in an anterior-posterior direction. Clinical studies conducted to date have shown that the accelerometer to be superior to the conventional vibration activity pacemakers, as far as the discrimination of different workloads and rejection of unwanted environmental noise are concerned.

We studied the effect of laser-induced shock waves in 94 arterial segments from freshly obtained autopsy material. In analogy to the well-established method of shock-wave based lithotripsy, the new principle of our treatment depends on an indirect interaction of the laser energy with the arterial wall via laser-induced mechanical shock waves (angiotripsy). We used a Nd:YAG laser, 1064 nm, 8-20 ns pulse-length to create shock waves that effected smooth craters in arteriosclerotically affected arteries. The histological examination found no thermal damage. Shock waves applied to the healthy and normal arterial wall only resulted in focal intimal ablation and in a minor loosening of the medial structures. The examination of the irrigation solution by means of a laser-guided, high-resolution analysis of the particles revealed that, in 97%, the particles created by our shock wave angiotripsy showed a diameter of less than 5 mm and an area of less than 25 mm2. Based on these first in vitro results, it seems possible to ablate arteriosclerotically affected tissue without significant damage to normal wall segments. Further in vitro and in vivo studies are required to evaluate the clinical implications of this new therapeutic approach.

In the past, the most important feature in the development of rate-responsive pacemaker systems was ensuring an adequate rate response to physical exercise. But there are other variables that modulate the rate of the healthy heart; examples include postural changes in heart rate in order to prevent orthostatic reactions, and the nightly decrease in intrinsic pacemaker rate. Therefore, we developed a sensor that could distinguish, not only rest and activity, but also discriminate between a supine and an upright position. This sensor is a multicontact tilt switch, which contains a small mercury ball. By measuring the number of openings and closures within the sensor as the ball touches the numerous sensor contacts it is possible to discriminate between different levels of exercise; the contact pins are circled around the base plate. There is an almost linear increase in the number of changes per time with increasing exercise. Besides measuring body activity from the number of contact changes per time, it is also possible to determine the body's posture from the count and positioning of the closed contacts within the casing. Based upon the results of 12 volunteers and nine pacemaker patients, a new algorithm is being prepared which enables the pacemaker to decrease stimulation rate in the supine position, to increase it in the upright position, and to correlate pacing rate with the increase in physical exercise. There is a good correlation between number of contact changes and the intrinsic heart rate (r = 0.87).

Rate-adaptive pacemakers are increasingly becoming part of clinical routine, the most widespread systems being activity-controlled. In order to shed more light on the foundations of mechanical forces which can possibly be utilized for controlling rate-adaptive systems, we conducted tests on six healthy volunteers and six pacemaker patients. With the aid of three orthogonal wide-band linear acceleration pick-ups attached to the body, the mechanical signals were recorded from the three axes during different activities. Along with standardized exercise on bicycle and treadmill ergometers, we tested the influence of household activities and interference influences. The results were analyzed in terms of the amplitude and frequency content of the signals. For walking activities we found a signal amplitude increasing in largely linear fashion with the walking speed, the signal amplitudes being approximately twice as high on the vertical axis as on the other two axes. Exercise on the bicycle ergometer produced mechanical signals of clearly lower amplitude than comparable walking activities. The Fast-Fourier analysis showed amplitude peaks in the low frequency range of 1 to 4 Hz for all forms of physiological exercise, while interference influences showed amplitude peaks mainly in the range above 8 Hz. The use of an acceleration pickup and a corresponding low pass filter might be a way of reducing the effect of nonphysiological interference influences on an activity-controlled pacemaker system. A sensor measuring in the horizontal axis appears to be the most favorable compromise for the various types of exercise. However, due to the considerable difference in signal amplitude for different types of exercise of the same intensity, an activity-controlled pacemaker system cannot entirely meet metabolic conditions and requirements.

In the past, thought about rate responsive pacing mainly focused on rate increase with exercise but did not consider that a rate increase with postural changes also is mandatory in order to prevent orthostatic reactions. A nightly decrease in pacemaker rate when the body is at rest and in a supine position is a further advantage for the patient's sleep and recovery. Therefore, we developed a sensor that could detect not only rest and body activity but also discriminate between a supine and an upright position. This sensor is a multicontact tilt switch containing a small mercury ball, as shown in the left panel of the figure below. The principle of discrimination between rest and low and high body activity is realized by the movement of the mercury ball resulting from body motion, which causes openings and closures within the sensor as the ball touches the numerous sensor contacts. In the upright position, a distinct number of contacts at the bottom of the tilt switch are closed. In the supine position, there is no closure of the bottom contacts and a postural discrimination can be achieved. We studied 12 volunteers and 10 pacemaker patients with this new device both at rest and during physical exercise. The right panel of the figure illustrates that the contacts per second correlate to the increase of physical exercise, such as walking on the treadmill. Further studies with an external pacemaker containing a small sensor suitable to fit into the pacemaker are in preparation.

A new rate-modulated pacemaker system optimized by combination of two sensors is described. The parameter body activity and central venous blood temperature control the pacemaker rate. The specific characteristic of each parameter determines its role within the algorithm. While the motion sensor yields a fast reaction following the onset or a change of stress intensity, central venous blood temperature corresponds better to body metabolism. An indication of increased exercise from the motion sensor results in an accordingly rapid increase in the pacing rate. Unless this increased exercise is confirmed by an increase in central venous blood temperature within 2 or 3 minutes, the new motion level will be assumed to be the new baseline motion value and the pace rate will return to a basic pacing rate. Prolonged inappropriate responses are therefore avoided. Longer lasting exercise, fever and nonphysiological signals are recognized and handled safely. Exercise tests with five volunteers under various conditions showed pacing rate behavior that was close to normal.