Health app policy: international comparison of nine countries' approaches.

An abundant and growing supply of digital health applications (apps) exists in the commercial tech-sector, which can be bewildering for clinicians, patients, and payers. A growing challenge for the health care system is therefore to facilitate the identification of safe and effective apps for health care practitioners and patients to generate the most health benefit as well as guide payer coverage decisions. Nearly all developed countries are attempting to define policy frameworks to improve decision-making, patient care, and health outcomes in this context. This study compares the national policy approaches currently in development/use for health apps in nine countries. We used secondary data, combined with a detailed review of policy and regulatory documents, and interviews with key individuals and experts in the field of digital health policy to collect data about implemented and planned policies and initiatives. We found that most approaches aim for centralized pipelines for health app approvals, although some countries are adding decentralized elements. While the countries studied are taking diverse paths, there is nevertheless broad, international convergence in terms of requirements in the areas of transparency, health content, interoperability, and privacy and security. The sheer number of apps on the market in most countries represents a challenge for clinicians and patients. Our analyses of the relevant policies identified challenges in areas such as reimbursement, safety, and privacy and suggest that more regulatory work is needed in the areas of operationalization, implementation and international transferability of approvals. Cross-national efforts are needed around regulation and for countries to realize the benefits of these technologies.

Cardiovascular autonomic adaptation in lunar and martian gravity during parabolic flight.

PURPOSE: Weightlessness has a well-known effect on the autonomic control of the cardiovascular system. With future missions to Mars in mind, it is important to know what the effect of partial gravity is on the human body. We aim to study the autonomic response of the cardiovascular system to partial gravity levels, as present on the Moon and on Mars, during parabolic flight. METHODS: ECG and blood pressure were continuously recorded during parabolic flight. A temporal analysis of blood pressure and heart rate to changing gravity was conducted to study the dynamic response. In addition, cardiovascular autonomic control was quantified by means of heart rate (HR) and blood pressure (BP) variability measures. RESULTS: Zero and lunar gravity presented a biphasic cardiovascular response, while a triphasic response was noted during martian gravity. Heart rate and blood pressure are positively correlated with gravity, while the general variability of HR and BP, as well as vagal indices showed negative correlations with increasing gravity. However, the increase in vagal modulation during weightlessness is not in proportion when compared to the increase during partial gravity. CONCLUSIONS: Correlations were found between the gravity level and modulations in the autonomic nervous system during parabolic flight. Nevertheless, with future Mars missions in mind, more studies are needed to use these findings to develop appropriate countermeasures.

Adaptation of autonomic heart rate regulation in astronauts after spaceflight.

BACKGROUND: Spaceflight causes changes in the cardiovascular control system. The aim of this study was to evaluate postflight recovery of linear and nonlinear neural markers of heart rate modulation, with a special focus on day-night variations. MATERIAL/METHODS: Twenty-four-hour Holter ECG recordings were obtained in 8 astronauts participating in space missions aboard the International Space Station (ISS). Data recording was performed 1 month before launch, and 5 and 30 days after return to Earth from short- and long-term flights. Cardiovascular control was inferred from linear and nonlinear heart rate variability (HRV) parameters, separately during 2-hour day and 2-hour night recordings. RESULTS: No remarkable differences were found in the postflight recovery between astronauts from short- and long-duration spaceflights. Five days after return to Earth, vagal modulation was significantly decreased compared to the preflight condition (day: p=0.001; night: p=0.019), while the sympathovagal balance was strongly increased, but only at night (p=0.017). A few nonlinear parameters were reduced early postflight compared to preflight values, but these were not always statistically significant. No significant differences remained after 30 days of postflight recovery. CONCLUSIONS: Our results show that 5 days after return from both short- and long-duration space missions, neural mechanisms of heart rate regulation are still disturbed. After 1 month, autonomic control of heart rate recovered almost completely.

Cardiac autonomic dysfunction in West syndrome.

BACKGROUND: West syndrome is an age-dependent epileptic encephalopathy. Autonomic changes are increasingly being recognized in patients with epilepsy: cardiac autonomic function is mediated by sympathetic and parasympathetic efferent activity to the heart and can provide information on the functional state of the autonomic nervous system. The goal of the study is to evaluate the effect of an early epileptic encephalopathy on the autonomic nervous system by measuring heart rate variability. METHODS: Cardiac autonomic function was evaluated in 13 patients with West syndrome by measuring heart rate variability during 5 min epochs of ECG in wake, stage 2 and slow wave sleep. In 5 patients who developed subsequently another type of epilepsy, a second evaluation was performed after 3 years of follow-up. RESULTS: Results showed a lower heart rate in stage 2 sleep in patients with West syndrome. Spectral components did not show significant differences compared to age matched controls at the moment of presentation. After follow-up of 3 years we were able to demonstrate higher low frequency (LF), lower high frequency (HF) and a higher LF/HF ratio during slow wave sleep. CONCLUSION: This study shows a lower heart rate in patients presenting with West syndrome, already at the onset of the syndrome and before ACTH treatment. The epileptic encephalopathy is not sufficient to alter spectral components of heart rate at the moment of presentation. However, already after 3 years of epilepsy, chronic autonomic changes appear.

Autonomic effects of refractory epilepsy on heart rate variability in children: influence of intermittent vagus nerve stimulation.

AIM: Vagus nerve stimulation (VNS) is a therapeutic option for individuals with refractory epilepsy. Individuals with refractory epilepsy are prone to dysfunction of the autonomic nervous system. Reduced heart rate variability is a marker of dysfunction of the autonomic nervous system. Our goal was to study heart rate variability in children with refractory epilepsy and the influence of VNS on this parameter. METHODS: In 17 children (13 male; four female; mean age 7 y 6 mo; age range 3-16 y) with refractory epilepsy, electroencephalographic and electrocardiographic data were obtained before and after implantation of VNS during stage 2 and slow-wave sleep. Time and frequency domain parameters were calculated and the results were compared with an age- and sex-matched group of individuals without refractory epilepsy. RESULTS: Our results show that autonomic cardiac control is affected in individuals with refractory epilepsy. There is a striking reduction in vagal tone during slow-wave sleep and modulation capacity is smaller than in individuals without refractory epilepsy. Implantation of VNS induces a shift in sympathovagal balance towards sympathetic predominance and an improvement in autonomic modulation. INTERPRETATION: Heart rate variability is affected in children with refractory epilepsy, and changes after implantation of VNS. The observed changes could be of importance in the cardiac complications of individuals with epilepsy and should be explored in more detail.

Instantaneous changes in heart rate regulation due to mental load in simulated office work.

The cardiac regulation effects of a mental task added to regular office work are described. More insight into the time evolution during the different tasks is created by using time-frequency analysis (TFA). Continuous wavelet transformation was applied to create time series of instantaneous power and frequency in specified frequency bands (LF 0.04-0.15 Hz; HF 0.15-0.4 Hz), in addition to the traditional linear heart rate variability (HRV) parameters. In a laboratory environment, 43 subjects underwent a protocol with three active conditions: a clicking task with low mental load and a clicking task with high mental load (mental arithmetic) performed twice, each followed by a rest condition. The heart rate and measures related to vagal modulation could differentiate the active conditions from the rest condition, meaning that HRV is sensitive to any change in mental or physical state. Differences between physical and mental stress were observed and a higher load in the combined task was observed. Mental stress decreased HF power and caused a shift toward a higher instantaneous frequency in the HF band. TFA revealed habituation to the mental load within the task (after 3 min) and between the two tasks with mental load. In conclusion, the use of TFA in this type of analysis is important as it reveals extra information. The addition of a mental load to a physical task elicited further effect on HRV parameters related to autonomic cardiac modulation.

Time-frequency heart rate variability characteristics of young adults during physical, mental and combined stress in laboratory environment.

The goal of this study was to evaluate the changes in heart rate variability (HRV) parameters due to a specific physical, mental or combined load. More specifically, the difference in effect between mental load and physical activity is studied. In addition, the effect of the combined physical and mental demand on the HRV parameters was examined and compared with the changes during the single task. In a laboratory environment, 28 subjects went through a protocol with different types of load (physical and/or mental), each followed by a period of rest. Continuous wavelet transformation was applied to create time series of instantaneous power and frequency in specified frequency bands (LF and HF). HF could distinguish the active conditions from the rest condition, meaning that HRV is sensitive to any change in mental or physical state. Differences in HRV parameters were observed between physical, mental and the combined load. In conclusion, we were able to distinguish between rest, physical and mental condition by combining different HRV characteristics. The addition of a mental load to a physical task had an extra effect on the HRV characteristics.

Heart rate variability during REM and non-REM sleep in preterm neonates with and without abnormal cardiorespiratory events.

AIM: Analyse heart rate variability (HRV) of preterm neonates undergoing a polysomnography in relation to the occurrence of abnormal cardiorespiratory events on one hand and the type of sleep states on the other hand. METHODS: To quantify nonlinear HRV, the numerical noise titration technique is used, adapted to neonatal heart rate data. HRV is calculated for 30 preterm neonates with mean post-conceptional age of 36.4weeks, divided into three groups according to the occurrence of abnormal events during the polysomnographies and the eventual home monitoring. RESULTS: Periods of non-REM sleep have lower noise limit values and can be distinguished significantly from periods of REM sleep and from the total recording period. The presence of abnormal events does not influence this finding. Significant differences between groups are only found during non-REM segments by means of the noise limit value computed via numerical noise titration while the linear HRV parameters were not able to discriminate. CONCLUSION: ECG measurement of a relatively short non-REM sleep period without specific abnormal events is sufficient to define a mature cardiorespiratory pattern in preterm infants.

Complexity of cardiovascular regulation in small animals.

Oscillations of heart rate and blood pressure are related to the activity of the underlying control mechanism. They have been investigated mostly with linear methods in the time and frequency domains. Also, in recent years, many different nonlinear analysis methods have been applied for the evaluation of cardiovascular variability. This review presents the most commonly used nonlinear methods. Physiological understanding is obtained from various results from small animals.