This study investigated the immediate effect of slow yoga breathing at 6 breaths per minute simultaneously on working memory performance and heart rate variability in yoga practitioners. A total of 40 healthy male volunteers performed a working memory task, ‘n-back’, consisting of three levels of difficulty, 0-back, 1-back, and 2-back, separately, before and after three SYB sessions on different days. The SYB sessions included alternate nostril breathing, right nostril breathing, and breath awareness. Repeated measures analysis of variance showed a significant (...) reduction in reaction time in 2-back condition immediately after ANB, RNB and BAW practices. Similarly, the accuracy was improved in the 0-back condition after RNB, and in the 2-back condition after ANB and RNB practices. These results suggest that SYB practice enhances cognitive abilities related to memory load and improves the functioning of cardiac autonomic activity, which is required for the successful completion of mental tasks.Trial registered in the Clinical Trials Registry of India. (shrink)

Occupational therapy often uses craft activities as therapeutic tools, but their therapeutic effectiveness has not yet been adequately demonstrated. The aim of this study was to examine changes in frontal midline theta rhythm and autonomic nervous responses during craft activities, and to explore the physiological mechanisms underlying the therapeutic effectiveness of occupational therapy. To achieve this, we employed a simple craft activity as a task to induce Fmθ and performed simultaneous EEG and ECG recordings. For participants in which Fmθ (...) activities were provoked, parasympathetic and sympathetic activities were evaluated during the appearance of Fmθ and rest periods using the Lorenz plot analysis. Both parasympathetic and sympathetic indices increased with the appearance of Fmθ compared to during resting periods. This suggests that a relaxed-concentration state is achieved by concentrating on craft activities. Furthermore, the appearance of Fmθ positively correlated with parasympathetic activity, and theta band activity in the frontal area were associated with sympathetic activity. This suggests that there is a close relationship between cardiac autonomic function and Fmθ activity. (shrink)

ObjectiveTo assess the impact of the closure of group-based cardiac rehabilitation training during the first COVID-19 lockdown in spring 2020 on patients’ physical activity, cardiorespiratory fitness, and cardiovascular risk, and to describe the patient experience of lockdown and home-based exercise training during lockdown.DesignMixed methods study. Prospectively collected post-lockdown measurements were compared to pre-lockdown medical record data. Quantitative measurements were supplemented with qualitative interviews about the patient experience during lockdown.SettingOutpatient CR centre in Salzburg, Austria.ParticipantsTwenty-seven patients [six female, mean age (...) 69 years] who attended weekly CR training sessions until the first COVID-19 lockdown in March 2020.Outcome MeasureQuantitative: exercise capacity, cardiovascular risk. Qualitative: individual semi-structured interviews.ResultsExercise capacity had significantly reduced from pre- to post-lockdown: mean power in maximal ergometry 165 vs. 151, p < 0.001; submaximal ergometer training 99 vs. 97, p = 0.038. There was no significant difference in Framingham risk score and other cardiovascular risk factors. Qualitative data showed that almost all patients had kept physically active during lockdown, but 17 said they had been unable to maintain their exercise levels, and 15 felt their cardiorespiratory fitness had deteriorated. Many patients missed the weekly CR training and the motivation and sense of community from training together with others. Several patients stated that without professional supervision they had felt less confident to carry out home-based exercise training at high intensity.ConclusionThis study highlights the importance of group-based supervised exercise training for patients who engage well in such a setting, and the detrimental impact of disruption to this type of CR service on physical activity levels and exercise capacity. Additionally, learning from the COVID-19 pandemic may inform the development and implementation of remote CR modalities going forward. (shrink)

Limitations of antiarrhythmic drugs on cardiac sudden death prevention appeared since the early 80's. The "Cardiac Arrhythmia Suppression Trial"(CAST) showed more recently that mortality was significantly higher inpatients treated with some particular antiarrhythmic drugs than in non-treated patients. In this field, our group recently demonstrated that a bolus of a Class 1B antiarrhythmic drug was able to trigger a ventricular fibrillation due to transient blocks induction. The aim of the present work was to systematically study, by use of (...) the van Capelle and Durrer (VCD) model which allows to simulate ventricular activation wave propagation, the link between arrhythmogenic effects and the ability of transient blocks to possibly degenerate in severe arrhythmias. A fragment of the ventricular wall is represented by an array of 16384elements electrically coupled. Effects of induction of one or several transient blocks, as the effects of their size and duration on possible induction of reentries have been studied. Results obtained show that various combinations between these different parameters may trigger reentries, ventricular tachycardia and/or more complex patterns assimilable to ventricular fibrillation. These results clearly evidence the fact that possible induction of transient blocks may directly be related to risk factor associated to arrhythmogenic effects of antiarrhythmic drugs. (shrink)

This article applies a theoretical framework developed by the late American sociologist Anselm Strauss to the discovery of a new resuscitation technique, closed-chest cardiac massage. The discovery, which took place in the laboratories of Johns Hopkins University between 1956 and 1960, is analyzed as the collective management of a trajectory over time. The article follows the discovery trajectory from its origins in defibrillator research to the establishment of closed-chest cardiac massage and cardiopulmonary resuscitation as a universal life-saving method. (...) The analytical focus on the experimental, clinical, and promotional activities performed by the different actors interacting with the emerging technology allows one to critically question the value of concepts such as closure, stabilization, and black boxing in sociology of science and technology. Instead of prematurely freezing the analysis of technoscience, a trajectory conceptual framework emphasizes the ongoing dynamic between actors and medical technology to define the scope, effectiveness, and multiple interpretations of the technology-actor interaction. (shrink)

The present work is aimed at investigating the effects of myocardial infarction and ischemia on induction of ventricular fibrillation. Electrophysiologic effects of global and local ischemia (variation of the dispersion of refractory periods as well as conduction velocity) on initiation of reentry mechanisms was studied by means of computer simulations based on a cellular automata model of propagation of activation wave through a ventricular surface element. A local area of ischemia where effects of the dispersion of refractory periods are investigated (...) is then simulated. This is made using a Gaussian distribution characterized by its mean and standard deviation. These simulations show that ischemia is capable of initiating reentry phenomena which propagate through the whole ventricle; they are responsible for ventricular fibrillation which causes sudden cardiac death, even when ischemia only involves limited parts of the myocardium. Statistical study of the probability of reentries as a function of both of the size of ischemic zones and the rate of dispersion of refractory periods shows that the latter parameter is of primary importance in triggering cardiac reentries. (shrink)

We used computer simulations to study the possible role of the dispersion of cellular coupling, refractoriness or both, in the mechanisms underlying cardiac arrhythmias. Local ischemia was first assumed to induce cell to cell dispersion of the coupling resistance (Case 1), refractory period (Case 2), or both of them (Case 3). Our numerical experiments based on the van Capelle and Durrer model showed that vortices could not be induced by cell to cell variations. With cellular properties dispersed in a (...) patchy way within the ischemic zone, a single activation wave could give rise to abnormal activities. This demonstrates the stability of the wave front under small inhomogeneities. Probabilities of reentry, estimated for the three cases cited above showed that a severe alteration of the coupling resistance may be an important factor in the genesis of reentry. Moreover, use of isochronal maps revealed that vortices were both stable and sustained with an alteration of the coupling alone or combined with a reduction of the action potential duration. Conversely, simulations with reduction of the refractoriness alone, inducing only transient patterns, could exhibit functionally determined reentries. (shrink)

In pathological conditions associated with persistent increases in hemodynamic workload (old myocardial infarction, high blood pressure, valvular heart disease), a number of signalling pathways are activated in the heart, all of which promote hypertrophic growth of the heart, characterised at the cellular level by increases in individual cardiac myocyte size. Some of these pathways are required for a successful adaptation to cardiac injury. Other pathways are maladaptive, however, as they lead to progressive contractile dysfunction and heart failure. The (...) free radical gas nitric oxide and natriuretic peptides, both of which are produced in the heart, have emerged as endogenous inhibitors of maladaptive hypertrophy signalling. Overall, it appears that cardiac hypertrophy is controlled by an interplay of pro‐ and antihypertrophic signalling networks. This delicate balance can tip towards adaptation or heart failure. In the future, patients living with cardiac disease may benefit from therapeutic strategies targeting maladaptive hypertrophy signalling pathways. BioEssays 26:608–615, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

Organ donation after cessation of circulation and respiration, both controlled and uncontrolled, has been proposed by the Institute of Medicine as a way to increase opportunities for organ procurement. Despite claims to the contrary, both forms of controlled and uncontrolled donation after cardiac death raise significant ethical and legal issues. Identified causes for concern include absence of agreement on criteria for the declaration of death, nonexistence of universal guidelines for duration before stopping resuscitation efforts and techniques, and assumption of (...) presumed intent to donate for the purpose of initiating temporary organ-preservation interventions when no expressed consent to donate is present. From a legal point of view, not having scientifically valid criteria of cessation of circulation and respiration for declaring death could lead to a conclusion that organ procurement itself is the proximate cause of death. Although the revised Uniform Anatomical Gift Act of 2006 provides broad immunity to those involved in organ-procurement activities, courts have yet to provide an opinion on whether persons can be held liable for injuries arising from the determination of death itself. Preserving organs in uncontrolled donation after cardiac death requires the administration of life-support systems such as extracorporeal membrane oxygenation. These life-support systems can lead to return of signs of life that, in turn, have to be deliberately suppressed by the administration of pharmacological agents. Finally, allowing temporary organ-preservation interventions without expressed consent is inherently a violation of the principle of respect for a person's autonomy. Proponents of organ donation from uncontrolled donation after cardiac death, on the other hand, claim that these nonconsensual interventions enhance respect for autonomy by allowing people, through surrogate decision making, to execute their right to donate organs. However, the lack of transparency and the absence of protection of individual autonomy, for the sake of maximizing procurement opportunities, have placed the current organ-donation system of opting-in in great jeopardy. Equally as important, current policies enabling and enhancing organ procurement practices, pose challenges to the constitutional rights of individuals in a pluralistic society as these policies are founded on flawed medical standards for declaring death. (shrink)

Recent EEG studies on the early postmortem interval that suggest the persistence of electrophysiological coherence and connectivity in the brain of animals and humans reinforce the need for further investigation of the relationship between the brain’s activity and the dying process. Neuroscience is now in a position to empirically evaluate the extended process of dying and, more specifically, to investigate the possibility of brain activity following the cessation of cardiac and respiratory function. Under the direction of the (...) Center for Healthy Minds at the University of Wisconsin-Madison, research was conducted in India on a postmortem meditative state cultivated by some Tibetan Buddhist practitioners in which decomposition is putatively delayed. For all healthy baseline and postmortem subjects presented here, we collected resting state electroencephalographic data, mismatch negativity, and auditory brainstem response. In this study, we present HB data to demonstrate the feasibility of a sparse electrode EEG configuration to capture well-defined ERP waveforms from living subjects under very challenging field conditions. While living subjects displayed well-defined MMN and ABR responses, no recognizable EEG waveforms were discernable in any of the tukdam cases. (shrink)

Stimulation of airway myocytes by contractile agents such as acetylcholine (ACh) activates a Ca2+-activated Cl– current (IClCa) which may play a key role in calcium homeostasis of airway myocytes and hence in airway reactivity. The aim of the present study was to model IClCa in airway smooth muscle cells using a computerised model previously designed for simulation of cardiac myocyte functioning. Modelling was based on a simple resistor-battery permeation model combined with multiple binding site activation by calcium. In order (...) to validate the model, a combination of equations, used to mimic [Ca2+]i response to ACh stimulation, were incorporated into the model. The results indicate that the model developed in this article accounts for experimental recordings and electrophysiological characteristics of this current in airway smooth muscle cells, with parameter values consistent with those calculated from experimental data. Such a model may thus be used to predict IClCa functioning, though additional experimental data from airway myocytes would be useful to more accurately determine some parameter values of the model. (shrink)

There is evidence from neuropsychological and psychophysical measurements that conscious sensory information is processed in discrete time segments. The segmentation process may be described as neuronal activity at a frequency of 40 Hz. Stimulus-induced neuronal activities of this frequency are found in the middle latency range of the auditory evoked potential . First, we have studied the effects of different general anesthetics on MLAEP and auditory evoked 40-Hz activity. Second, we investigated MLAEP and explicit and implicit memory for (...) information presented during cardiac anesthesia. In the awake patients peak latencies of the MLAEP were in the normal range. An auditory evoked 40-Hz activity was present 20–100 ms poststimulus. Under nonspecific anesthetics MLAEP and the 40-Hz activity were suppressed, and under receptor-specific agents MLAEP and the 40-Hz activity were partly preserved. None of the cardiac patients had conscious explicit recall of the intraoperative events, whereas some patients showed unconscious implicit memory for an intraoperative tape message. The implicit memory could be related to midlatency auditory evoked potentials. No implicit memory was detectable when MLAEP and the primary cortical processing of the auditory stimuli and 40-Hz activity were blocked. Implicit memory could be detected in more than 50% of the cases when MLAEP, a 30-Hz activity, and the primary cortical stimulus processing were preserved. In conclusion, our observations support the view that a high frequency oscillatory mechanisms, recorded as a grouped neuronal activity in the MLAEP, may be part of a basic neuronal program for conscious sensory information processing. (shrink)

In Denmark, which alone in Western Europe has not accepted brain death as the criterion of death, the newly established Danish Council of Ethics has issued a report suggesting that in Denmark the criterion of death should still be the cessation of cardiac activity. The council bases its conclusion on the concept of death in everyday experience and its ethical implications.

Over the years, researchers have enriched the postulation that hedonic products generate deeper emotional reactions and feelings in the consumer than functional products. However, recent research empirically proves that hedonic products are more affect-rich only for some consumers segments or for specific consumption contexts. We argue that such inconsistency may derive from the nature of the emotions assessed, that is strictly dependent on their empirical measurement, and not from the mere existence of emotions themselves. Self-reported methods of evaluating consumer experience, (...) on which prior studies are grounded, only assess conscious emotions the consumer can recognize and report, but not unconscious feelings, happening without individual awareness. The present work takes this challenge by conducting a laboratory experiment in which subjects are exposed to both a utilitarian product and a hedonic product. Physiological measures have been adopted to investigate unconscious emotional responses and self-reported measures to assess conscious emotions toward the products. Specifically, physiological data regarding the subjects' cardiac activity, respiratory activity, electrodermal activity, and cerebral activity have been collected and complemented with a survey. Results confirm that both functional and hedonic products generate emotional responses in consumers. Further, findings show that when a consumer is exposed to a functional product, the physiological emotional responses are disassociated from the self-reported ones. A diverse pattern is depicted for hedonic products. We suggest an alternative explanation for the apparent lack of affect-rich experiences elicited by functional products and the need to re-consider emotional responses for these products. (shrink)

Emotions are a natural vector for acting together with others and are witnessed in human behaviour, perception and body functions. For this reason, studies of human-to-human interaction, such as multi-person motor synchronisation, are a perfect setting to disentangle the linkage of emotion with socio-motor interaction. And yet, the majority of joint action studies aiming at understanding the impact of emotions on multi-person performance resort to enacted emotions, the ones that are emulated based on the previous experience of such emotions, and (...) almost exclusively focus on dyadic interaction. In addition, tasks chosen to study emotion in joint action are frequently characterised by a reduced number of physical dimensions to gain experimental control and subsequent facilitation in data analysis. Therefore, it is not clear how naturalistically induced emotions diffuse in more ecological interactions with other people and how emotions affect the process of interpersonal synchronisation. Here, we show that positive and negative emotions differently alter spontaneous human synchronous behaviour during a multi-person improvisation task. The study involved 39 participants organised in triads who self-reported liking improvisational activities. The task involved producing improvisational movements with the right hand. Participants were emotionally induced by manipulated social feedback involving a personal ranking score. Three-dimensional spatio-temporal data and cardiac activity were extracted and transformed into oscillatory signals to compute behavioural and physiological synchrony. Our results demonstrate that individuals induced with positive emotions, as opposed to negative emotions or a neutral state, maintained behavioural synchrony with other group members for a longer period of time. These findings contribute to the emerging shift of neuroscience of emotion and affective sciences towards the environment of social significance where emotions appear the most—in interaction with others. Our study showcases a method of quantification of synchrony in an improvisational and interactive task based on a well-established Kuramoto model. (shrink)

Understanding the effect of stress, fatigue, and sleep deprivation on the ability to maintain an alert and attentive state in an ecologically valid setting is of importance as lapsing attention can, in many safety-critical professions, have devastating consequences. Here we studied the effect of close-quarters battle exercise combined with overnight military training with sleep deprivation on cognitive performance, namely sustained attention and response inhibition. In addition, the effect of the CQ battle and overnight training on cardiac activity [heart (...) rate and root mean square of the successive differences ] during the cognitive testing and the relationship between cardiac activity and cognitive performance were examined. Cognitive performance was measured with the psychomotor vigilance task and the sustained attention to response task. Altogether 45 conscripts participated in the study. The conscripts were divided into control and experimental groups. The CON completed the training day after a night of sleep and the EXP after the overnight military training with no sleep. Results showed that the effect of the overnight training on cognitive performance and the between-group difference in heart rate and heart rate variability depended on the cognitive test. Surprisingly, the cognitive performance was not largely affected by the CQ battle. However, as expected, the CQ battle resulted in a significant decrease in RMSSD and an increase in HR measured during the cognitive testing. Similarly, the HR parameters were related to cognitive performance, but the relationship was found only with the PVT. In conclusion, fatigue due to the overnight training impaired the ability to maintain sufficient alertness level. However, this impairment in arousal upregulation was counteracted by the arousing nature of the SART. Hence, the conscripts' cognitive performance was mainly preserved when performing a stimulating task, despite the fatigue from the sleep loss of the preceding night and physical activity. (shrink)

In the outpatient ultrasound suite of a major urban medical center, the mood is somber. A young woman lies tense and anxious. Pregnant for the first time, she has experienced early first-trimester bleeding. The radiologist relates the ultrasound findings: there has been a small hemorrhage, but there is a six-week-size fetus with normal cardiac activity. Translation: the baby is alive! The woman quietly sobs, happy but apprehensive.Across the drive, in the main hospital building, a young boy lies unresponsively (...) comatose in the Pediatric Intensive Care Unit. He was hit by a car while riding his bicycle. He is relying on a ventilator to breath, but his cardiovascular system is supporting itself. After a series... (shrink)

Background:The decision whether to initiate cardiopulmonary resuscitation may sometimes be ethically complex. While studies have addressed some of these issues, along with the role of nurses in cardiopulmonary resuscitation, most have not considered the importance of nurses acting as advocates for their patients with respect to cardiopulmonary resuscitation.Research objective:To explore what the nurse’s advocacy role is in cardiopulmonary resuscitation from the perspective of patients, relatives, and health professionals in the Basque Country (Spain).Research design:An exploratory critical qualitative study was conducted from (...) October 2015 to March 2016. Thematic analysis was used to analyse the data.Participants:Four discussion groups were held: one with patients and relatives (n = 8), two with nurses (n = 7 and n = 6, respectively), and one with physicians (n = 5).Ethical considerations:Approval was obtained from the Basque Country Clinical Research Ethics Committee.Findings:Three significant themes were identified: (a) accompanying patients during end of life in a context of medical dominance, (b) maintaining the pact of silence, and (c) yielding to legal uncertainty and concerns.Discussion:The values and beliefs of the actors involved, as well as pre-established social and institutional rules reduced nurses’ advocacy to that of intermediaries between the physician and the family within the hospital environment. On the contrary, in primary health care, nurses participated more actively within the interdisciplinary team.Conclusion:This study provides key information for the improvement and empowerment for ethical nursing practice in a cardiac arrest, and provides the perspective of patients and relatives, nurses and physicians. (shrink)

Anna Chavlovski,1 Greg A Knoll,1–3 Timothy Ramsay,4 Swapnil Hiremath,1–3 Deborah L Zimmerman1–31University of Ottawa, 2Ottawa Hospital, 3Kidney Research Centre, Ottawa Hospital Research Institute, 4Ottawa Methods Centre, Ottawa, ON, CanadaBackground: In patients with end-stage renal disease, use of vitamin D and calcium-based phosphate binders have been associated with progression of vascular calcification that might have an impact on renal transplant candidacy. Our objective was to examine management of mineral metabolism in patients wait-listed for renal transplant and to determine the impact on (...) cardiac perfusion imaging.Methods: Data was collected retrospectively on patients wait-listed for a renal transplant, being either active and on hold. Demographic data, medications, serum concentrations of calcium, phosphate, parathyroid hormone, and cardiac perfusion imaging studies were collected from the electronic health record. Chi-square and Student’s t-tests were used to compare active and on-hold patients as appropriate. Logistic regression was used to examine variables associated with worsening cardiac imaging studies.Results: The wait-listed patients were of mean age 56 ± 14 years and had been on dialysis for 1329 ± 867 days. On-hold patients had received a significantly greater total dose of calcium and were more likely to have developed worsening cardiovascular imaging studies. Total doses of calcium and calcitriol were associated with worsening cardiovascular imaging studies.Conclusion: Patients on hold on the renal transplant waiting list received higher total doses of calcium. A higher total dose of calcium and calcitriol was also associated with worsening cardiovascular imaging. Time on dialysis before transplant has been associated with worse post-transplant outcomes, and it is possible that the total calcium and calcitriol dose received contributed to these inferior outcomes.Keywords: dialysis, calcium, cardiac, transplantation. (shrink)

The aim of this work was to compare experimental investigations on effects of lidocaine, calcium and, BRL 34915 on reentries to simulated data obtained by use of a model of propagation based on the Huygens' constriction method already described in previous works. Calcium and lidocaine effects are investigated on anisotropic conduction conditions. In both cases, reduction in conduction velocities are observed. In lidocaine case, a refractory area is located along the longitudinal axis. In agreement with experimental electrical mapping, the simulations (...) show that the stabilization of reentrant excitation is mainly due to the existence of this refractory area around which the reentrant circuit can develop. The experimental study shows that BRL 34915 has both arrhythmogenic and antiarrhythmic effects. A detailed electrophysiological analysis has shown that drug infusion act on normal cardiac cells by decreasing the relative and absolute refractory period. BRL 34915 action is simulated by a decrease in the refractory period showing that the time frequency of the reentrant activity is increased and that the spatial size where the reentry is developing is becoming smaller. These two effects are arrhythmogenic, the simulated data being so in good agreement with the experimental ones. (shrink)

This paper discusses a classic Aristotelian understanding of science, nature, and methods of inquiry and proof. It then discusses nursing as a practical science and provides some demonstrations through the application of classical methods. In the Aristotelian tradition an individual substance is a unity of form and matter: form being the intelligible universal that becomes the concept, while matter is the principle of individuation. Science is mediate intellectual causal knowledge. Inquiry uses hypothetical argument, and proof that is from valid syllogistic (...) reasoning with true premises provides necessity and certitude. This proof requires knowledge of the natural kind that gives origin to the attributes under investigation. The variability of nature is overcome by reasoning on the supposition of the end.Within the classical understanding of speculative and practical science, nursing is a practical science. As a science, nursing investigates the principles and causes of its subject, be that human beings, health or nursing behaviours as knowable nursing operations. The goal is knowledge of practice for the sake of practice, but nursing as a science is not operable. Nursing practice, that is nursing art or technologies, must complete the science. Reasoning on the supposition of the end, for example of cardiac compensation, allows one to identify necessary activities and physical states. Three causal demonstrations about decubiti show that demonstrations are possible. Classical science would teach us that the practical science of nursing studies human nature in order to identify principles and causes of health and principles and causes of nursing operations themselves. It also requires that the science ends in practical operation. Thus, proper decisions and individual actions in particular patient situations must complete nursing science. (shrink)

The popular subject of near‐death experiences (NDEs) occupies a potentially crucial place in scholarly discussions of topics such as human nature and the possibility of an afterlife. This chapter investigates primarily one key subject: the topic of whether NDE observations provide any potential evidence for the existence of a conscious human self during a ND state, such as when neither the heart nor the brain register any known activity. Increasingly, the most evidential NDE cases are usually thought to occur (...) especially when the corroboration is produced during a state of cardiac arrest due to ventricular fibrillation. Yet, Michael Marsh is immensely impressed with the real transformations that seem to affect ND experiencers (NDErs). Alternative rejoinders no longer seem to have truly made as many gains in the most recent conversations, including Marsh's own hypothesis of a waking brain. (shrink)

We live in the era of Facebook, Fitbit, and Skype. As such, it would be unreasonable to expect that the healthcare industry would not see the same kind of globalization as do our social spheres and consumer activities. Indeed, the explosion of information technology, the ease of transcontinental travel, and the emergence of a more globally aware citizenry allows for scientific collaboration that has had many positive effects on global health. However, the economic and structural disparities between systems of healthcare (...) delivery in the industrialized world and parts of the developing world have created a monster in the form of an international medical tourism industry that endangers the health and safety of citizens of the host country as well as visiting patients. Not only does the practice of medical tourism pose a practical danger to those in direct contact with the industry, but it brings up troubling philosophical problems centering on national responsibility and the commodification of healthcare, among other important issues. In the United States, the driving force behind international medical tourism is the exorbitant cost of healthcare, particularly for the uninsured but also for the underinsured and those who experience catastrophic medical expenses from chronic illness or sudden health crises. Not only have individuals begun to look outside the U.S. for surgical procedures and other expensive therapies, but employers have begun to toy with the idea of outsourcing the medical care of the employees they insure in order to cut costs. In other industrialized nations, the issues that underpin international medical tourism are related to healthcare rationing and reflect different shortcomings in the delivery of healthcare in those nations, such as the United Kingdom and Canada, that have single-payer systems. Yet the regulatory and philosophical implications for both patients and hosts of international healthcare are largely the same. The challenge of regulating international trade in medical care is obvious and becomes particularly acute when there are insurers and employers involved. Complicating matters further, medical care that takes place outside the country of origin of the patient is often brokered by “medical concierge services,” which, though quick to claim indemnity from any harm arising from substandard or inappropriate medical care, cannot be divorced from responsibility for the health outcomes of their clients. Agreements hashed out between concierge services and patients specify that any remedy for harm stemming from their medical care must be pursued within the confines of the law of the host country, but the practical implications of this are troublesome. How can a foreign patient—often without either linguistic or cultural competency in the host country—be expected to navigate the complexity of a foreign legal system, particularly one that may be far less developed than his home country? Furthermore, if insurance companies and employers are involved with such care, who pays for an adverse result or determines responsibility for harm that may befall the patient? Under which countries’ laws? If a patient travels to Singapore for sexual reassignment surgery or a cardiac valve repair, returns to the States and suffers complications, who pays for the restoration of her health? Beyond legal standards and judicial remedies for harm to patients seeking care on the international market, there is the question of what ethical standards and norms apply to such patients. What effect does it have on American patients, for example, to receive care within a system that does not emphasize autonomy and informed consent the way they are used to? Why should foreign physicians care about the cultural mores of their patients’ country of origin? Can they be expected to grasp cultural differences between American, Canadian, and British patients? The medical concierge might respond, “Well, buyer beware!” This is unreasonable: It is nearly impossible for any patient to accurately assess the various options, risks and benefits that go with a particular medical treatment, much less the patient who is attempting to do so on the international market. And the crass invocation of the doctrine of caveat emptor betrays a view of healthcare as a commodity that is naive and inappropriate. Paramount in my mind, however, are the practical implications for the care of the citizens of developing nations that host international patients and the broader philosophical issue of what the goals of the medical profession as a whole and each country’s individual healthcare system should be. While I understand the argument that international medical tourism creates great economic gains for developing nations, which can then be channeled toward the care of their citizenry as a whole, there is much reason to doubt that this “trickle-down” model of economics provides real benefits for underserved, whether in healthcare or other arenas. What is more likely is that, while lucrative international “medi-cities” may keep bright doctors in their home countries, it is also likely to lure them away from the institutions that serve the lion’s share of their countrymen. With the concentration of talented native doctors in private hospitals that serve citizens of the developed world, the population at large is left to obtain care at institutions that suffer “brain drain” from the flight of talented local staff to more prestigious, often “brand name,” institutions that give them more Western-like salaries while allowing them to practice in their countries of origin. The very fact that citizens of the wealthiest nations in the world are forced to go abroad for life-saving care speaks to an abdication of national responsibility on the part of their home countries. The provision of health care is one of the principal responsibilities of any nation and it is unacceptable that a nation with the strength and wealth of the United States would take advantage of the weaker political and economic situations of developing nations in order to shirk its responsibility to its fellow citizens. If we take care of our countrymen and take pride in an equitable system of healthcare delivery, there will be no need to shrug our shoulders and say “Buyer beware” to the patient who heads to the Philippines for heart surgery. (shrink)

The aim of this work was to compare experimental investigations on effects of lidocaine, calcium and, BRL 34915 on reentries to simulated data obtained by use of a model of propagation based on the Huygens' constriction method already described in previous works. Calcium and lidocaine effects are investigated on anisotropic conduction conditions. In both cases, reduction in conduction velocities are observed. In lidocaine case, a refractory area is located along the longitudinal axis. In agreement with experimental electrical mapping, the simulations (...) show that the stabilization of reentrant excitation is mainly due to the existence of this refractory area around which the reentrant circuit can develop. The experimental study shows that BRL 34915 has both arrhythmogenic and antiarrhythmic effects. A detailed electrophysiological analysis has shown that drug infusion act on normal cardiac cells by decreasing the relative and absolute refractory period. BRL 34915 action is simulated by a decrease in the refractory period showing that the time frequency of the reentrant activity is increased and that the spatial size where the reentry is developing is becoming smaller. These two effects are arrhythmogenic, the simulated data being so in good agreement with the experimental ones. (shrink)

This paper aims to determine whether it is necessary to propose the extreme of putrefaction as the only unmistakable sign in diagnosing the death of the human organism, as David Oderberg does in a recent paper. To that end, we compare Oderberg’s claims to those of other authors who align with him in espousing the so-called theory of hylomorphism but who defend either a neurological or a circulatory-respiratory criterion for death. We then establish which interpretation of biological phenomena is the (...) most reasonable within the metaphysical framework of hylomorphism. In this regard, we hold that technology does not obscure the difference between life and death or confect metaphysically anomalous beings, such as living human bodies who are not organisms or animals of the human species who are informed by a vegetative soul, but instead demands a closer and more careful look at the “fuzzy area” between a healthy organism and a decaying corpse. In the light of hylomorphism, we conclude that neurological and circulatory-respiratory criteria are not good instruments for diagnosing death, since they can offer only probabilistic prognoses of death. Of the two, brain death is further away from the moment of death as it merely predicts cardiac arrest that will likely result in death. Putrefaction, the criterion that Oderberg proposes, is at the opposite end of the fuzzy area. This is undoubtedly a true diagnosis of death, but it is not necessary to wait for putrefaction proper—a relatively late stage of decomposition—to be sure that death has already occurred. Rather, early cadaveric phenomena demonstrate that the matter composing a body is subject to the basic forces governing all matter in its environment and has thus succumbed to the universal current of entropy, meaning that the entropy-resisting activity has ceased to constitute an organismal unity. When this unity is lost, there is no possibility of return. (shrink)

Clinical ethics has been developing in paediatric healthcare for several decades. However, information about how paediatricians use clinical ethics case consultation services is extremely limited. In this project, we analysed a large set of case records from the clinical ethics service of one paediatric hospital in Australia. We applied a paediatric-specific typology to the case referrals, based on the triadic doctor–patient–parent relationship. We reviewed the 184 cases referred to the service in the period 2005–2014, noting features including the type of (...) case, the referring department(s) and the patient9s age at referral. The two most common types of referral involved clinician uncertainty about the appropriate care pathway for the child (26% of total referrals) and situations where the child9s parents disagreed with the doctors’ recommendations for the child9s care (22% of total referrals). Referrals came from 28 different departments. Cancer, cardiology/cardiac surgery and general medicine referred the highest numbers of cases. The most common patient age groups were children under 1, and 14–15 years old. For three controversial areas of paediatric healthcare, clinicians had initiated processes of routine review of cases by the clinical ethics service. These insights into the way in which one very active paediatric clinical ethics service is used further our understanding of the work of paediatric clinical ethics, particularly the kinds of ethically challenging cases that paediatricians view as appropriate to refer for clinical ethics support. (shrink)

Atrial fibrillation is the most common cardiac arrhythmia in clinical practice. It often starts with asymptomatic and short episodes, which are difficult to detect without the assistance of automatic monitoring tools. The vast majority of methods proposed for this purpose are based on quantifying the irregular ventricular response during the arrhythmia. However, although AF totally alters the atrial activity reflected on the electrocardiogram, replacing stable P-waves by chaotic and time-variant fibrillatory waves, this information has still not been explored (...) for automated screening of AF. Hence, a pioneering AF detector based on quantifying the variability over time of the AA morphological pattern is here proposed. Results from two public reference databases have proven that the proposed method outperforms current state-of-the-art algorithms, reporting accuracy higher than 90%. A less false positive rate in the presence of other arrhythmias different from AF was also noticed. Finally, the combination of this algorithm with the classical analysis of RR series variability also yielded a promising trade-off between AF accuracy and detection delay. Indeed, this combination provided similar accuracy than RR-based methods, but with a significantly shorter delay of 10 beats. (shrink)

I focus on some differences between negative emotional states and how they are coped with in explaining different cardiac risks. The different cognitive, motivational, and physiological characteristics of emotions imply different appraisals of the negative event, and different resources to cope with the event. Cardiovascular activity depends on these different appraisals and coping strategies. For example, cortisol levels have shown to be differently associated with anger and fear responses to social stress. In addition, different ways to regulate one’s (...) emotions are also associated with different bodily responses that may increase or decrease cardiac risks. Future research should not only examine different emotions to stressors, but also more long-term regulation strategies and coping resources, such as self-esteem. (shrink)

This paper addresses a dichotomy in the attitudes of some clinicians and bioethicists regarding whether there is a moral difference between deactivating a cardiac pacemaker in a highly dependent patient at the end of life, as opposed to standard cases of withdrawal of treatment. Although many clinicians hold that there is a difference, some bioethicists maintain that the two sorts of cases are morally equivalent. The author explores one potential morally significant point of difference between pacemakers and certain other (...) life-sustaining treatments: specifically, that the former are biofixtures, which become part of the patient in a way that the latter do not. The concept of the pacemaker as biofixture grants pacemakers a unique moral status that gives reason to treat a pacemaker the same as other parts of the patient that are necessary to sustain life. The author employs this biofixture analysis to affirm the intuition that deactivating a pacemaker in a highly dependent patient at the end of life is, in moral terms, more analogous to active euthanasia than it is to standard cases of withdrawal of treatment. The paper concludes with consideration of potential implications for further implantable medical technologies, such as ventricular assist devices and total artificial hearts. (shrink)

The situation-dependent lateralization of sympathetic electrodermal arousal during real-life stress may challenge a unitary notion of arousal, and call into question the practice of unilateral electrodermal recording, but there are broader implications. Here we consider a potential relationship between stress-induced lateralized shifts in electrodermal activity, and a theory concerning lateralized emotion-induced cardiac arrhythmia.

The study of the autonomic nervous system (ANS) function has shown to provide useful indicators for risk stratification and early detection on a variety of cardiovascular pathologies. However, data gathered during different tests of the ANS are difficult to analyse, mainly due to the complex mechanisms involved in the autonomic regulation of the cardiovascular system (CVS). Although model-based analysis of ANS data has been already proposed as a way to cope with this complexity, only a few models coupling the main (...) elements involved have been presented in the literature. In this paper, a new model of the CVS, representing the ventricles, the circulatory system and the regulation of the CVS activity by the ANS, is presented. The models of the vascular system and the ventricular activity have been developed using the Bond Graph formalism, as it proposes a unified representation for all energetic domains, facilitating the integration of mechanic and hydraulic phenomena. In order to take into account the electro-mechanical behaviour of both ventricles, an electrophysiologic model of the cardiac action potential, represented by a set of ordinary differential equations, has been integrated. The short-term ANS regulation of heart rate, cardiac contractility and peripheral vasoconstriction is represented by means of continuous transfer functions. These models, represented in different continuous formalisms, are coupled by using a multi-formalism simulation library. Results are presented for two different autonomic tests, namely the Tilt Test and the Valsalva Manoeuvre, by comparing real and simulated signals. (shrink)

An anencephalic infant, who came to be known as Baby K, was born at Fairfax Hospial in Falls Church, Virginia, on October 13, 1992. From, the moment of birth and repeatedly thereafter, the baby's mother insisted that aggressive measures be pursued, including cardiopulmonary resuscitation and ventilator support, to keep the baby alive as long as possible. The physicians complied. However, following the baby's second admission for respiratory failure, the hospital sought declaratory relief from the court permitting it to forgo emergency (...) life support on the grounds that “a requirement to provide respiratory assistance would exceed the prevailing standard of medical care,” and that “because any treatment of their condition is futile, the prevailing standard of medical care for infants with anencephaly is to provide warmth, nutrition, and hydration.” The United States Court of Appeals for the Fourth Circuit ruled in favor of the baby's mother, citing the federal Emergency Medical Treatment and Active Labor Act , which contained no “standard of care” exception to the requirement to provide “treatment necessary to prevent the material deterioration of the individual's condition.” An appeal to the United States Supreme Court was rejected. The baby died some two and one-half years later of cardiac arrest during her sixth visit to the emergency department of Fairfax Hospital for respiratory failure. (shrink)

N- and O-linked glycan structures of cell surface and secreted glycoproteins serve a variety of functions related to cell–cell communication in systems affecting development and disease. The more sophisticated N-glycan biosynthesis pathway of metazoans diverges from that of yeast with the appearance of the medial-Golgi β-N-acetylglucosaminyltransferases (GlcNAc-Ts). Tissue-specific regulation of medial- and trans-Golgi glycosyltransferases contribute structural diversity to glycoproteins in metazoans, and this can affect their molecular properties including localization, half-life, and biological activity. Null mutations in glycosyltransferase genes positioned (...) later in the biosynthetic pathway disrupt expression of smaller subsets of glycan structures and are progressively milder in phenotype. In this review, we examine data on targeted mutations affecting glycosylation in mice and congenital mutations in man, with a view to understanding the molecular functions of glycan structures as modulators of glycoprotein activity. Finally, pathology associated with the expression of GlcNAc-Ts in cancer and diabetes-induced cardiac hypertrophy suggest that inhibitors of these enzymes may have therapeutic value. BioEssays 21:412–421, 1999. © 1999 John Wiley & Sons, Inc. (shrink)

To foster understanding in the psychopathology of patients with anorexia nervosa at the psychological and physiological level, standardized experimental studies on reliable biomarkers are needed, especially due to the lack of disorder-specific samples. To this end, the autonomic nervous system response to a psychosocial stressor was investigated in n = 19 PAN, age, and gender-matched to n = 19 healthy controls. For this purpose, heart rate and heart rate variability parameters were assessed in a cross-sectional study design under two experimental (...) conditions: rest and stress. In addition, psychological indicators of stress were assessed. An 2 × 2 × 8 ANOVA demonstrated similar HR and HRV patterns between PAN and HC at rest. Under stress, PAN demonstrated a blunted HR [condition*time*group: F = 9.326, p = 0.000, η2 = 0.206] and an attenuated HRV response. Significant effects of stress appraisal and BMI on HRV-reactivity were revealed. SA on SDNN = Condition*time*SA = F = 2.676, p = 0.033, η2 = 0.073. BMI on LF/HF-Ratio = Condition*time*BMI = F = 3.339, p = 0.019, η2 = 0.164. Psychological indices suggested higher levels of chronic and appraised stress in PAN relative to HC. Additional analyses demonstrated that ED-symptoms are highly correlated with the latter constructs, as well as with psychological burden, but not with weight. Further, it was shown that abnormalities in reactivity persisted despite normalized ANS activity. Overall, we suggested that besides weight recovery, improvement in stress appraisal could be beneficial for cardiac health. In this light, a combination of therapy and biofeedback training may improve treatment outcomes and regulate stress reactivity. (shrink)

The study of the autonomic nervous system (ANS) function has shown to provide useful indicators for risk stratification and early detection on a variety of cardiovascular pathologies. However, data gathered during different tests of the ANS are difficult to analyse, mainly due to the complex mechanisms involved in the autonomic regulation of the cardiovascular system (CVS). Although model-based analysis of ANS data has been already proposed as a way to cope with this complexity, only a few models coupling the main (...) elements involved have been presented in the literature. In this paper, a new model of the CVS, representing the ventricles, the circulatory system and the regulation of the CVS activity by the ANS, is presented. The models of the vascular system and the ventricular activity have been developed using the Bond Graph formalism, as it proposes a unified representation for all energetic domains, facilitating the integration of mechanic and hydraulic phenomena. In order to take into account the electro-mechanical behaviour of both ventricles, an electrophysiologic model of the cardiac action potential, represented by a set of ordinary differential equations, has been integrated. The short-term ANS regulation of heart rate, cardiac contractility and peripheral vasoconstriction is represented by means of continuous transfer functions. These models, represented in different continuous formalisms, are coupled by using a multi-formalism simulation library. Results are presented for two different autonomic tests, namely the Tilt Test and the Valsalva Manoeuvre, by comparing real and simulated signals. (shrink)

The study of the autonomic nervous system (ANS) function has shown to provide useful indicators for risk stratification and early detection on a variety of cardiovascular pathologies. However, data gathered during different tests of the ANS are difficult to analyse, mainly due to the complex mechanisms involved in the autonomic regulation of the cardiovascular system (CVS). Although model-based analysis of ANS data has been already proposed as a way to cope with this complexity, only a few models coupling the main (...) elements involved have been presented in the literature. In this paper, a new model of the CVS, representing the ventricles, the circulatory system and the regulation of the CVS activity by the ANS, is presented. The models of the vascular system and the ventricular activity have been developed using the Bond Graph formalism, as it proposes a unified representation for all energetic domains, facilitating the integration of mechanic and hydraulic phenomena. In order to take into account the electro-mechanical behaviour of both ventricles, an electrophysiologic model of the cardiac action potential, represented by a set of ordinary differential equations, has been integrated. The short-term ANS regulation of heart rate, cardiac contractility and peripheral vasoconstriction is represented by means of continuous transfer functions. These models, represented in different continuous formalisms, are coupled by using a multi-formalism simulation library. Results are presented for two different autonomic tests, namely the Tilt Test and the Valsalva Manoeuvre, by comparing real and simulated signals. (shrink)

The ventricular pressure profile is characteristic of the cardiac contraction progress and is useful to evaluate the cardiac performance. In this contribution, a tissue-level electromechanical model of the left ventricle is proposed, to assist the interpretation of left ventricular pressure waveforms. The left ventricle has been modeled as an ellipsoid composed of twelve mechano-hydraulic sub-systems. The asynchronous contraction of these twelve myocardial segments has been represented in order to reproduce a realistic pressure profiles. To take into account the (...) different energy domains involved, the tissue-level scale and to facilitate the building of a modular model, multiple formalisms have been used: Bond Graph formalism for the mechano-hydraulic aspects and cellular automata for the electrical activation. An experimental protocol has been defined to acquire ventricular pressure signals from three pigs, with different afterload conditions. Evolutionary Algorithms have been used to identify the model parameters in order to minimize the error between experimental and simulated ventricular pressure signals. Simulation results show that the model is able to reproduce experimental ventricular pressure. In addition, electro-mechanical activation times have been determined in the identification process. For example, the maximum electrical activation time is reached, respectively, 96.5, 139.3 and 131.5 ms for the first, second, and third pigs. These preliminary results are encouraging for the application of the model on non-invasive data like ECG, arterial pressure or myocardial strain. (shrink)

Ventricular Fibrillation is responsible for a majority of sudden cardiac death, but little is known about how ventricular tachycardia (VT) degenerates into ventricular fibrillation. Several clinical studies focused only on preventing VT with a class III antiarrhythmic drug resulted in many deaths. Our simulations investigate the interactions between an antiarrhythmic drug likely to suppress a VT and a Figure 8 reentry. A parameter AAR is introduced to increase the action potential duration and therefore simulate various Class III drugs. Simulations (...) are ran under several conditions (phases of the reentry, values of AAR, durations). They show that a VT can be suppressed whatever the phase of the reentry but it strongly depends on the duration of the effect. It confirms that a drug which can suppress a reentry can also worsen it. It also shows a great variety of activation patterns and thus the complexity of antiarrhythmic drugs effects. Simulations also demonstrate that suppressing VT is an increasing function of AAR. (shrink)

Hospitalization is a unique health-illness transition for most elderly people. Whether the patient's health-related needs are met or not often iiifluence his or her appraisal of quality of life during hospitalization. This qualitative study explored the health needs of elderly Chinese male cardiac patients during their hospitalization. Eighteen subjects were recruited from a veterans' hospital in northern Taiwan. These men all lived alone before their hospital admission. Data were gathered using semistructured interviews and then analysed by content analysis. Ninety-four (...) per cent of the subjects described up to three categories of needs: met needs (72%), unmet needs (78%), and expected needs (50%0). Needs that participants believed were met were those for psychological support, spiritual support, tangible support and information. Unmet needs were those for participation in decision making, maintaining daily activities and resuming a preadmission lifestyle. The expected needs included those for learning self-care strategies to maintain their daily activities after discharge from the hospital. The factors that framed the participants' perceptions of different health needs were identified to be lack of family support and locus of control. Finally, a discussion of the context background of this phenomenon, as well as some suggestions for its implications, are provided from a culturally sensitive ethical aspect. (shrink)

Biological pacemakers can be achieved by various gene‐based and cell‐based approaches. Embryonic stem cells (ESCs)‐derived pacemaker cells might be the most promising way to form biological pacemakers, but there are challenges as to how to control the differentiation of ESCs and to overcome the neoplasia, proarrhythmia, or immunogenicity resulting from the use of ESCs. As a potential approach to solve these difficult problems, tissue‐engineering techniques may provide a precise control on the different cell components of multicellular aggregates and the forming (...) of a construct with‐defined architectures and functional properties. The combined interactions between ESC‐derived pacemaker cells, supporting cells, and matrices may completely reproduce pacemaker properties and result in a steady functional unit to induce rhythmic electrical and contractile activities. As ESCs have a high capability for self‐renewal, proliferation, and potential differentiation, we hypothesize that ESCs can be used as a source of pacemaker cells for tissue‐engineering applications and the ambitious goal of biological cardiac pacemakers may ultimately be achieved with ESCs via tissue‐engineering technology. (shrink)

Biological pacemakers can be achieved by various gene‐based and cell‐based approaches. Embryonic stem cells (ESCs)‐derived pacemaker cells might be the most promising way to form biological pacemakers, but there are challenges as to how to control the differentiation of ESCs and to overcome the neoplasia, proarrhythmia, or immunogenicity resulting from the use of ESCs. As a potential approach to solve these difficult problems, tissue‐engineering techniques may provide a precise control on the different cell components of multicellular aggregates and the forming (...) of a construct with‐defined architectures and functional properties. The combined interactions between ESC‐derived pacemaker cells, supporting cells, and matrices may completely reproduce pacemaker properties and result in a steady functional unit to induce rhythmic electrical and contractile activities. As ESCs have a high capability for self‐renewal, proliferation, and potential differentiation, we hypothesize that ESCs can be used as a source of pacemaker cells for tissue‐engineering applications and the ambitious goal of biological cardiac pacemakers may ultimately be achieved with ESCs via tissue‐engineering technology. -/- . (shrink)