Neurocardiology: therapeutic implications for cardiovascular disease

Influence of Primary Neurologic Disease on Cardiovascular Health in Females

Neurocardiology is an interdisciplinary field that examines the complex interactions between the nervous and the cardiovascular systems, exploring how neurological processes, such as autonomic nervous system regulation and brain-heart communication impact heart function and contribute to cardiovascular health and disease. Although much of the focus on cardiovascular health has centered on traditional risk factors, the influence of the nervous system, especially in females, is increasingly recognized as a key determinant of cardiovascular outcomes. This article reviews existing literature on the neurological mechanisms that impact cardiovascular function in females. Specifically, we analyze how primary neurological disorders including cerebrovascular disease, headache disorders, and multiple sclerosis have specific downstream effects on cardiac function. By understanding the complex relationship between neurological and cardiovascular health, this review highlights the need for sex-specific approaches to prevention, diagnosis, and treatment of cardiovascular disease in females, ultimately encouraging the discovery of more effective care strategies and improving health outcomes.

Somatovisceral influences on emotional development

Frameworks of emotional development have tended to focus on how environmental factors shape children's emotion understanding. However, individual experiences of emotion represent a complex interplay between both external environmental inputs and internal somatovisceral signaling. Here, we discuss the importance of afferent signals and coordination between central and peripheral mechanisms in affective response processing. We propose that incorporating somatovisceral theories of emotions into frameworks of emotional development can inform how children understand emotions in themselves and others. We highlight promising directions for future research on emotional development incorporating this perspective, namely afferent cardiac processing and interoception, immune activation, physiological synchrony, and social touch.

A Heart without Life: Artificial Organs and the Lived Body

The use of artificial organs is likely to increase in the future, given technological advances, increases in chronic diseases, and limited donor organs. This article examines how artificial organs could affect people's experience and conceptualization of bodies and our understanding of the relation of body to self. I focus on artificial heart devices and argue that these have two conflicting potential influences. First, they may influence people to regard the body as machinelike and separable from the self. Second, they may effect changes to subjective experience that can be understood as changes to the self, confirming the self's embodiment. My primary purpose is to increase our understanding of what might change if it becomes more usual to have a body that is partly nonorganic. But I also argue that the analysis points to potential ethical concerns related to strengthening biomedical conceptions of the body and to the devaluing of bodies and body parts.

Vagal effects of endocrine HPA axis challenges on resting autonomic activity assessed by heart rate variability measures in healthy humans

BACKGROUND

The hypothalamic-pituitary-adrenal axis (HPA axis) and the autonomic nervous system (ANS) are considered to play the most crucial role in the pathophysiology of stress responsiveness and are increasingly studied together. However, only few studies have simultaneously assessed HPA axis and ANS activity to investigate their direct interaction in pathophysiology, while no study so far has assessed the dynamic interplay between the two systems in healthy subjects through endocrine challenges.

METHODS

The present study assessed the direct effects of overnight pharmacoendocrine HPA axis challenges with dexamethasone (suppression) and metyrapone (stimulation) on ANS activity at rest as determined by linear and nonlinear measures of heart rate variability (HRV) in 39 young healthy individuals.

RESULTS

Findings indicated significant effects of metyrapone, but not dexamethasone on autonomic activity at rest based on HRV measures. HRV after metyrapone was overall significantly reduced in comparison to baseline or post-dexamethasone conditions, while the combined metyrapone-related reduction of HRV measures RMSSD, NN50(%) and HF(%) with concomitant increase of the unifractal scaling coefficient α_fast value jointly indicated a specifically diminished vagal activity.

CONCLUSIONS

We provide first data that HPA axis stimulation (metyrapone) is associated with reduced vagal tone, while HPA axis suppression (dexamethasone) has no effect on autonomic modulation of heart function. Our results support a vital role of the parasympathetic nervous system in the interplay between ANS and HPA axis and, thus, in the modulation of stress-related cardiovascular responsiveness and the susceptibility to stress-related disorders.

Early warning signals for critical transitions in cardiopulmonary health, related to air pollution in an urban Chinese population

Respiratory, and cardio-cerebrovascular health-related diseases significantly threaten human health and together with air pollution form a complex pathophysiological system. Other complex biological systems show that increased variance and autocorrelations in time series may act as valid early warning signals for critical transitions. On population level, we determined the likelihood that increased variance and autocorrelation of hospital visit on cardiopulmonary disease preceded critical transitions in population health by human-pollution interactions. We investigated long-term hospital visits from a hospital in Nanjing City, China during 2006-2016 for the most important cardiopulmonary diseases likely to be influenced by air pollution: cerebrovascular accident disease (CVAD), coronary artery disease (CAD), chronic obstructive pulmonary disease (COPD), lung cancer disease (LCD), and the grouped categories of respiratory system disease (RESD) and cardio-cerebrovascular system disease (CCD). The time series of standard deviations (SDs) and autocorrelation at-lag-1 (AR-1) were studied as potential Early-Warning Indicators (EWIs) of transitions in population health. Elevated SDs provided an early warning for critical transitions in visit for LCD and overall CCD and CVAD, for the period of 2012-2013, after which a real transition of increased visit occurred for these disease categories. Statistical testing showed that these SDs were significantly increased (p < 0.1). The long-term air pollution together with intermittent pollution episodes may have triggered critical transitions in population health for cardiopulmonary disease. It is recommended to consider significant increases in variability in time series of relevant system parameters, such as visit, as early warning signs for future transitions in populations' health states.

Cardiovascular complications after radiotherapy

Over the past decades, effective cancer therapies have resulted in a significant improvement in the survival rates for a number of cancers and an increase in the number of cancer survivors. Radiation therapy is widely used in the treatment of cancer, and it can induce various cardiotoxicities that differ considerably from chemotherapy-induced cardiotoxicity. They occur primarily as late radiation-induced complications, several years from the end of anticancer treatment and present as coronary artery disease, heart failure, pericardial disease, valvular heart disease and arrhythmias. Patients who recovered from cancer disease suffer from cardiac complications of anticancer treatment, it affects the quality of their lives and life expectancy, especially if the diagnosis is delayed. These patients may present distinct symptoms of cardiac injury, resulting from radiation-induced neurotoxicity and altered pain perception, which makes diagnosis difficult. This review highlights the need for a screening programme for patients who have undergone radiation therapy and which will subsequently have a potentially profound impact on morbidity and mortality.

Autonomic dysfunction is associated with cardiac remodelling in heart failure patients

Aims

Orthostatic hypotension (OH) is a cardinal sign of autonomic dysfunction and a common co‐morbidity in heart failure (HF). The role of autonomic dysfunction in the development of structural cardiac anomalies in HF patients has not been sufficiently explored. We aimed to assess relations between orthostatic blood pressure (BP) responses during active standing and echocardiographic changes in a series of patients admitted for HF.

Methods and results

One hundred and forty‐nine patients hospitalized for HF [mean age: 74 years; 30% women; ejection fraction (LVEF) 40 ± 16%] were examined with conventional echocardiograms and active‐standing test. Associations of cardiac remodelling parameters with the difference between supine and standing (after 3 min) systolic/diastolic BP were examined. Systolic BP decreased (−1.1 ± 15 mmHg), whereas diastolic BP increased (+1.0 ± 9.5 mmHg) after 3 min of active standing. A total of 34 patients (23%) met conventional OH criteria; i.e. systolic/diastolic BP decreases by ≥20/10 mmHg. In the multivariable linear regression analysis, adjusted for traditional cardiovascular risk factors and LVEF, a decrease in systolic BP upon standing was associated with greater left atrial volume [β per −10 mmHg: 2.37, standard error (SE) = 1.16, P = 0.043], and greater left ventricular mass (β per −10 mmHg: 5.67, SE = 2.24, P = 0.012), but not with other echocardiographic parameters. No significant associations were observed between signs of cardiac remodelling and decrease in diastolic BP.

Conclusions

Orthostatic decrease in systolic BP among older HF patients is associated with structural cardiac changes such as increased left atrial volume and left ventricular mass, independently of traditional risk factors and left ventricular dysfunction.

Studying the pathophysiologic connection between cardiovascular and nervous systems using stem cells

The cardiovascular and nervous systems are deeply connected during development, health, and disease. Both systems affect and regulate the development of each other during embryogenesis and the early postnatal period. Specialized neural crest cells contribute to cardiac structures, and a number of growth factors released from the cardiac tissue (e.g., glial cell line-derived neurotrophic factor, neurturin, nerve growth factor, Neurotrophin-3) ensure proper maturation of the incoming parasympathetic and sympathetic neurons. Physiologically, the cardiovascular and nervous systems operate in harmony to adapt to various physical and emotional conditions to maintain homeostasis through sympathetic and parasympathetic nervous systems. Moreover, neurocardiac regulation involves a neuroaxis consisting of cortex, amygdala, and other subcortical structures, which have the ability to modify lower-level neurons in the hierarchy. Given the interconnectivity of cardiac and neural systems, when one undergoes pathological changes, the other is affected to a certain extent. In addition, there are specific neurocardiac diseases that affect both systems simultaneously, such as Huntington disease, Lewy body diseases, Friedreich ataxia, congenital heart diseases, Danon disease, and Timothy syndrome. Over the last decade, in vitro modeling of neurocardiac diseases using induced pluripotent stem cells (iPSCs) has provided an invaluable opportunity to elevate our knowledge about the brain-heart connection, since previously primary cardiomyocytes and neurons had been extremely difficult to maintain long-term in vitro. Ultimately, the ability of iPSC technology to model abnormal functional phenotypes of human neurocardiac disorders, combined with the ease of therapeutic screening using this approach, will transform patient care through personalized medicine in the future. © 2016 Wiley Periodicals, Inc.

Rightward dominance in temporal high-frequency electrical asymmetry corresponds to higher resting heart rate and lower baroreflex sensitivity in a heterogeneous population

OBJECTIVE

Explore potential use of a temporal lobe electrical asymmetry score to discriminate between sympathetic and parasympathetic tendencies in autonomic cardiovascular regulation.

METHODS

131 individuals (82 women, mean age 43.1, range 13-83) with diverse clinical conditions completed inventories for depressive (CES-D or BDI-II) and insomnia-related (ISI) symptomatology, and underwent five-minute recordings of heart rate and blood pressure, allowing calculation of heart rate variability and baroreflex sensitivity (BRS), followed by one-minute, two-channel, eyes-closed scalp recordings of brain electrical activity. A temporal lobe high-frequency (23-36 Hz) electrical asymmetry score was calculated for each subject by subtracting the average amplitude in the left temporal region from amplitude in the right temporal region, and dividing by the lesser of the two.

RESULTS

Depressive and insomnia-related symptomatology exceeding clinical threshold levels were reported by 48% and 50% of subjects, respectively. Using a cutoff value of 5% or greater to define temporal high-frequency asymmetry, subjects with leftward compared to rightward asymmetry were more likely to report use of a sedative-hypnotic medication (42% vs. 22%, P = 0.02). Among subjects with asymmetry of 5% or greater to 30% or greater, those with rightward compared to leftward temporal high-frequency asymmetry had higher resting heart rate (≥5% asymmetry, 72.3 vs. 63.8, P = 0.004; ≥10%, 71.5 vs. 63.0, P = 0.01; ≥20%, 72.2 vs. 64.2, P = 0.05; ≥30%, 71.4 vs. 64.6, P = 0.05). Subjects with larger degrees of rightward compared to leftward temporal high-frequency asymmetry had lower baroreflex sensitivity (≥40% asymmetry, 10.6 vs. 16.4, P = 0.03; ≥50% asymmetry, 10.4 vs. 16.7, P = 0.05).

CONCLUSION

In a heterogeneous population, individuals with rightward compared to leftward temporal high-frequency electrical asymmetry had higher resting heart rate and lower BRS. Two-channel recording of brain electrical activity from bilateral temporal regions appears to hold promise for further investigation as a means to assess cortical activity associated with autonomic cardiovascular regulation.

Feasibility and preliminary findings from a pilot study of allostatic load in adolescent-young adult childhood cancer survivors and their siblings

Adolescent-young adult (AYA) childhood cancer survivors experience at least 2 types of chronic stress that can increase their risk for cardiovascular disease: the physiological stress of cancer and its treatment and the psychosocial stress inherent in the cancer experience. Their siblings can also experience ongoing cancer-related psychosocial stress. The composite biomarker allostatic load (AL) describes the cumulative impact of responses to chronic stress on interrelated organ systems and risk for stress-related diseases including cardiovascular disease. AL could be useful as a surrogate response indicator in research and care that aims to improve cardiovascular outcomes of childhood cancer. However, the measurement of AL has requirements to which AYA might not agree or adhere. This study aimed to (a) evaluate the feasibility of studying AL in AYA cancer populations and (b) briefly describe preliminary findings concerning psychological distress, cancer-related stress symptoms, health behavior and AL in AYA survivors and their siblings within the context of a small pilot study. The results support the feasibility of studying AL in AYA survivors and their siblings, and also suggest that further study of AL and risk for cardiovascular disease in both groups is indicated.