Posttraumatic stress disorder is associated with attenuated baroreceptor sensitivity among female, but not male, smokers

Autonomic dysfunction and cardiovascular risk in post-traumatic stress disorder

BACKGROUND

Patients with post-traumatic stress disorder (PTSD) have an increased risk for cardiovascular disease. The underlying mechanisms are unclear but impaired autonomic function may contribute. However, research in this field has shown contradictory results and the causal links between PTSD, autonomic dysfunction, and cardiovascular risk remain unknown. This brief review summarizes the current knowledge on alterations in autonomic function and cardiovascular risk in patients with PTSD.

LITERATURE SEARCH STRATEGY

A PubMed search of the literature was performed using the following keywords: autonomic function, heart rate variability, blood pressure variability, sympathetic activity, baroreflex function, and cardiovascular risk in combination with PTSD. Evidence-based studies conducted between 2000 and 2021 were selected.

RESULTS

In total 1221 articles were identified and of these, 61 (48 original research papers, 13 review articles) were included in this review. Many, though not all, studies have reported increased activity of the sympathetic nervous system and decreased activity of the parasympathetic nervous system (namely, autonomic imbalance) in PTSD patients. There seems to be enough evidence to suggest impairments in baroreflex function in PTSD, leading to blood pressure dysregulation. It appears that the chronicity of PTSD diagnosis and symptom severity are independent risk factors for cardiovascular disease, which may be linked with impaired autonomic function.

CONCLUSIONS

Increased cardiovascular risk may be associated with autonomic dysfunction in PTSD. Whether autonomic dysfunction can serve as a biomarker for the onset and progression of PTSD remains to be determined. It also needs to determine if autonomic imbalance increases the risk of developing PTSD.

The cardiac, vasomotor, and myocardial branches of the baroreflex in fibromyalgia: Associations with pain, affective impairments, sleep problems, and fatigue

This study investigated the cardiac, vasomotor, and myocardial branches of the baroreflex in fibromyalgia using the spontaneous sequence method. Systolic blood pressure (SBP), interbeat interval (IBI), stroke volume (SV), pre-ejection period (PEP), and total peripheral resistance (TPR) were continuously recorded in 40 fibromyalgia patients and 30 healthy individuals during a cold pressor test and a mental arithmetic task. Sequences of covariation between SBP and IBI (cardiac branch), SV and PEP (myocardial branch), and TPR (vasomotor branch) were identified. Baroreflex sensitivity (BRS) was represented by the slope of the regression line between values in the sequences; baroreflex effectiveness (BEI) was indexed by the proportion of progressive SBP changes that elicited reflex responses. Patients exhibited lower BRS in the three branches, lower BEI in the cardiac and vasomotor branches, and reduced reactivity in cardiac BRS and BEI, SBP, IBI, SV, and PEP. Moreover, BRS and BEI were inversely related to clinical pain, cold pressor pain, depression, trait anxiety, sleep problems, and fatigue. Reduced function of the three baroreflex branches implies diminished resources for autonomic inotropic, chronotropic, and vascular regulation in fibromyalgia. Blunted stress reactivity indicates a limited capacity for autonomic cardiovascular adjustment to situational requirements. The associations of BRS and BEI with pain perception may reflect the antinociceptive effects arising from baroreceptor afferents, where reduced baroreflex function may contribute to the hyperalgesia characterizing fibromyalgia. The associations with affective impairments, sleep problems, and fatigue suggest that baroreflex dysfunctions are also involved in the secondary symptoms of the disorder.

Sex differences in post-traumatic stress disorder risk: autonomic control and inflammation

AIM

Over 7 million U.S. adults and about 20% of the military population have post-traumatic stress disorder (PTSD), a debilitating condition that is independently linked to a significantly greater risk of developing cardiovascular disease (CVD). Women have twice the probability of developing PTSD after experiencing a traumatic event compared to men. Existing literatures have reported higher inflammation and autonomic dysfunction including impaired baroreflex sensitivity, increased sympathetic reactivity and decreased parasympathetic activity in PTSD. However, most of these findings stem from studies conducted predominantly in males.

METHODS

We attempt in this narrative review to summarize the mixed literature available on sex differences in autonomic dysfunction and inflammation in PTSD, at rest and in response to stress in PTSD.

RESULTS

This review reveals that there is a paucity of research exploring autonomic function in females with PTSD. Recent studies have included female participants without probing for sex differences. A small number of studies have been conducted exclusively in women. Available data suggest that sympathetic nervous system output tends to be heightened, while parasympathetic activity and arterial baroreflex sensitivity appear more blunted in females with PTSD. Although few studies have investigated sex differences in inflammation in PTSD, data within females suggest chronic increases in inflammation with PTSD. This autonomic dysregulation and inflammation have also been described in males with PTSD.

CONCLUSION

In sum, given the inherent biological differences in CVD clinical presentation and characteristics between men and women, human and animal studies aiming at elucidating sex differences in the pathophysiology of PTSD are needed.

Concussion and the autonomic nervous system: An introduction to the field and the results of a systematic review

BACKGROUND

Recent evidence suggests that autonomic nervous dysfunction may be one of many potential factors contributing to persisting post-concussion symptoms.

OBJECTIVE

This is the first systematic review to explore the impact of concussion on multiple aspects of autonomic nervous system functioning.

METHODS

The methods employed are in compliance with the American Academy of Neurology (AAN) and PRISMA standards. Embase, MEDLINE, PsychINFO, and Science Citation Index literature searches were performed using relevant indexing terms for articles published prior to the end of December 2016. Data extraction was performed by two independent groups, including study quality indicators to determine potential risk for bias according to the 4-tiered classification scheme of the AAN.

RESULTS

Thirty-six articles qualified for inclusion in the analysis. Only three studies (one Class II and two Class IV) did not identify anomalies in measures of ANS functioning in concussed populations.

CONCLUSIONS

The evidence supports the conclusion that it is likely that concussion causes autonomic nervous system anomalies. An awareness of this relationship increases our understanding of the physical impact of concussion, partially explains the overlap of concussion symptoms with other medical conditions, presents opportunities for further research, and has the potential to powerfully inform treatment decisions.

Noradrenergic dysregulation in the pathophysiology of PTSD

A central role for noradrenergic dysregulation in the pathophysiology of post-traumatic stress disorder (PTSD) is increasingly suggested by both clinical and basic neuroscience research. Here, we integrate recent findings from clinical and animal research with the earlier literature. We first review the evidence for net upregulation of the noradrenergic system and its responsivity to stress in individuals with PTSD. Next, we trace the evidence that the α₁ noradrenergic receptor antagonist prazosin decreases many of the symptoms of PTSD from initial clinical observations, to case series, to randomized controlled trials. Finally, we review the basic science work that has begun to explain the mechanism for this efficacy, as well as to explore its possible limitations and areas for further advancement. We suggest a view of the noradrenergic system as a central, modifiable link in a network of interconnected stress-response systems, which also includes the amygdala and its modulation by medial prefrontal cortex. Particular attention is paid to the evidence for bidirectional signaling between noradrenaline and corticotropin-releasing factor (CRF) in coordinating these interconnected systems. The multiple different ways in which the sensitivity and reactivity of the noradrenergic system may be altered in PTSD are highlighted, as is the evidence for possible heterogeneity in the pathophysiology of PTSD between different individuals who appear clinically similar. We conclude by noting the importance moving forward of improved measures of noradrenergic functioning in clinical populations, which will allow better recognition of clinical heterogeneity and further assessment of the functional implications of different aspects of noradrenergic dysregulation.

Distinctive cardiac autonomic dysfunction following stress exposure in both sexes in an animal model of PTSD

It is unclear whether the poor autonomic flexibility or dysregulation observed in patients with posttraumatic stress disorder (PTSD) represents a pre-trauma vulnerability factor or results from exposure to trauma. We used an animal model of PTSD to assess the association between the behavioral response to predator scent stress (PSS) and the cardiac autonomic modulation in male and female rats. The rats were surgically implanted with radiotelemetry devices to measure their electrocardiograms and locomotor activity (LMA). Following baseline telemetric monitoring, the animals were exposed to PSS or sham-PSS. Continuous telemetric monitoring (24h/day sampling) was performed over the course of 7days. The electrocardiographic recordings were analyzed using the time- and frequency-domain indexes of heart rate variability (HRV). The behavioral response patterns were assessed using the elevated plus maze and acoustic startle response paradigms for the retrospective classification of individuals according to the PTSD-related cut-off behavioral criteria. During resting conditions, the male rats had significantly higher heart rates (HR) and lower HRV parameters than the female rats during both the active and inactive phases of the daily cycle. Immediately after PSS exposure, both the female and male rats demonstrated a robust increase in HR and a marked drop in HRV parameters, with a shift of sympathovagal balance towards sympathetic predominance. In both sexes, autonomic system habituation and recovery were selectively inhibited in the rats whose behavior was extremely disrupted after exposure to PSS. However, in the female rats, exposure to the PSS produced fewer EBR rats, with a more rapid recovery curve than that of the male rats. PSS did not induce changes to the circadian rhythm of the LMA. According to our results, PTSD can be conceptualized as a disorder that is related to failure-of-recovery mechanisms that impede the restitution of physiological homeostasis.

Exploring the relationship between posttraumatic stress disorder symptoms and momentary heart rate variability

OBJECTIVE

Exposure to trauma-related cues has been associated with a prolonged decrease in heart rate variability (HRV) under laboratory conditions, however the relationship between PTSD symptoms and HRV has not been evaluated during everyday life. The present study sought to determine whether Posttraumatic Stress Disorder (PTSD) symptoms reported during everyday life were related to reduced HRV.

METHODOLOGY

Eighty-three young adults with PTSD underwent 24-hour Holter monitoring, during which PTSD symptoms were measured using ecological momentary assessment (EMA). Multilevel modeling was used to examine the association between PTSD symptom severity and low frequency (LF) and high frequency (HF) HRV.

RESULTS

PTSD symptoms were associated with reductions in LF HRV, independently of age and activity level. There was no significant association between PTSD symptom levels and HF HRV.

CONCLUSIONS

These results indicate that an association between momentary PTSD symptom severity and reduced LF HRV is significant and observable in young adults with PTSD. Findings highlight the need for cardiovascular screening in young adults with PTSD and early interventions that target physiological reactivity in PTSD.

Metabolic, autonomic and immune markers for cardiovascular disease in posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) has been associated with significantly greater incidence of heart disease. Numerous studies have indicated that health problems for individuals with PTSD occur earlier in life than in the general population. Multiple mechanistic pathways have been suggested to explain cardiovascular disese (CVD) risk in PTSD, including neurochemical, behavioral, and immunological changes. The present paper is a review of recent research that examines cardiovascular and immune risk profiles of individuals with PTSD. First, we address the relatively new evidence that the constellation of risk factors commonly experienced in PTSD fits the profile of metabolic syndrome. Next we examine the findings concerning hypertension/blood pressure in particular. The literature on sympathetic and parasympathetic responsivity in PTSD is reviewed. Last, we discuss recent findings concerning immune functioning in PTSD that may have a bearing on the high rates of CVD and other illnesses. Our primary goal is to synthesize the existing literature by examining factors that overlap mechanistically to increase the risk of developing CVD in PTSD.

The behavioral impact of baroreflex function: a review

The baroreflex consists of a negative feedback loop adjusting heart activity to blood pressure fluctuations. This review is concerned with interactions between baroreflex function and behavior. In addition to changes in baroreflex cardiac control subject to behavioral manipulations, interindividual differences in reflex function predicted psychological and central nervous features. The sensitivity of the reflex was inversely related to cognitive performance, evoked potential amplitudes, experimental pain sensitivity, and the severity of clinical pain. Possible variables moderating the strength of the associations are tonic blood pressure, gender, and psychiatric disease. It is suggested that these observations reflect inhibition of higher brain function by baroreceptor afferents. While in many cases increased baroreflex function implies stronger inhibition, individual and situational factors modulate the behavioral impact of cardiac regulation.

They know their trauma by heart: an assessment of psychophysiological failure to recover in PTSD

BACKGROUND

Posttraumatic stress disorder (PTSD) develops following exposure to atraumatic event and is characterized by persistent intense reactivity to trauma related cues. Equally important, but less studied, is the failure to restore physiological homeostasis after these excessive reactions. This study investigates psychophysiological markers of sustained cardiac activity after exposure to reminders of traumatic event in PTSD patients.

METHODS

Participants passively listened to neutral and personal traumatic event while electrocardiogram was continuously recorded. Heart rate (HR) and heart rate variability (HRV) were analyzed in 19 PTSD patients and 16 trauma-exposed controls.

RESULTS

Both PTSD patients and trauma exposed controls exhibited a significant increase in HR to the exposure of their personal trauma. PTSD patients sustained the increase of HR while controls recovered to basal levels. In PTSD patients, sustained HR was positively associated with re-experiencing symptoms. The PTSD group also showed a reduced HRV (a measure of parasympathetic influence on the heart) during personal trauma exposure and lack of recovery.

LIMITATIONS

The sample size was small and PTSD patients were under medication.

CONCLUSIONS

Our findings provide an experimental account of the failure of PTSD patients to exhibit physiological recovery after exposure to trauma-related stimuli. PTSD patients exhibited a sustained tachycardia with attenuation of HRV that persisted even after cessation of the stressor. Re-experiencing symptoms facilitated engagement in the trauma cues, suggesting that, in their daily-life, patients most likely present repeated episodes of sustained over-reactivity, which may underpin the emotional dysregulation characteristic of PTSD.

Medial prefrontal cortex N-methyl-D-aspartate receptor/nitric oxide/cyclic guanosine monophosphate pathway modulates both tachycardic and bradycardic baroreflex responses

Neural reflex mechanisms, such as the baroreflex, are involved in regulating cardiovascular system activity. Previous results showed that the ventral portion of the medial prefrontal cortex (vMPFC) is involved in modulation only of the cardiac baroreflex bradycardic component. Moreover, vMPFC N-methyl-D-aspartate (NMDA) receptors modulate the bradycardia baroreflex, but the baroreflex tachycardic component has not been investigated. Furthermore, glutamatergic neurotransmission into the vMPFC is involved in activation of the cardiac sympathetic and parasympathetic nervous system. Finally, it has been demonstrated that glutamatergic neurotransmission into the vMPFC can be modulated by the endocannabinoid system and that activation of the CB1 cannabinoid receptor by anandamide, an endocannabinoid, can decrease both cardiac baroreflex bradycardic and tachycardic responses. Thus, there is the possibility that glutamatergic neurotransmission into the vMPFC does not modulate only the cardiac bradycardic component of the baroreflex. Therefore, the present study investigated whether glutamatergic neurotransmission into the vMPFC modulates both cardiac baroreflex bradycardic and tachycardic responses. We found that vMPFC bilateral microinjection of the NMDA receptor antagonist AP7 (4 nmol/200 nl), of a selective inhibitor of neuronal nitric oxide (NO) synthase N-propyl (0.08 nmol/200 nl), of the NO scavenger carboxy-PTIO (2 nmol/200 nl), or of the NO-sensitive guanylate cyclase ODQ (2 nmol/200 nl) decreased the baroreflex activity in unanesthetized rats. Therefore, our results demonstrate the participation of NMDA receptors, production of NO, and activation of guanylate cyclase in the vMPFC in the modulation of both cardiac baroreflex bradycardic and tachycardic responses.

Posttraumatic stress disorder, cardiovascular, and metabolic disease: a review of the evidence

BACKGROUND

Posttraumatic stress disorder (PTSD) is a significant risk factor for cardiovascular and metabolic disease.

PURPOSE

The purpose of the current review is to evaluate the evidence suggesting that PTSD increases cardiovascular and metabolic risk factors, and to identify possible biomarkers and psychosocial characteristics and behavioral variables that are associated with these outcomes.

METHODS

A systematic literature search in the period of 2002-2009 for PTSD, cardiovascular disease, and metabolic disease was conducted.

RESULTS

The literature search yielded 78 studies on PTSD and cardiovascular/metabolic disease and biomarkers.

CONCLUSIONS

Although the available literature suggests an association of PTSD with cardiovascular disease and biomarkers, further research must consider potential confounds, incorporate longitudinal designs, and conduct careful PTSD assessments in diverse samples to address gaps in the research literature. Research on metabolic disease and biomarkers suggests an association with PTSD, but has not progressed as far as the cardiovascular research.

Sleep disturbance and baroreceptor sensitivity in women with posttraumatic stress disorder

In a previous study, women with posttraumatic stress disorder (PTSD) had greater objective sleep disturbance than those without PTSD. In a separate previous study, women with PTSD were also found to have lower baroreceptor sensitivity (BRS), an index of blood pressure regulation. In the present study, the authors concurrently assessed BRS and objective sleep by diagnostic status. A comparison of 32 women with PTSD with 21 women without PTSD revealed an interaction between BRS and sleep efficiency, wake after sleep onset percentage, and sleep fragmentation. Lower BRS was associated with poorer sleep in women with PTSD, but not in those without. Future research should investigate causal relationships between sleep and blood pressure regulation in those with PTSD.

Is posttraumatic stress disorder related to development of heart disease? An update

It has long been hypothesized that posttraumatic stress disorder (PTSD) increases coronary heart disease (CHD) risk; however, empirical evidence is limited. In the first prospective study to date, individuals with higher PTSD symptom levels had a significantly increased risk for CHD, after controlling for known coronary risk factors. PTSD indicates a chronic stress reaction and is hypothesized to influence CHD either by causing biological alterations that lead to cardiovascular damage, or by leading to adverse health behaviors that increase CHD risk. A key issue is whether PTSD contributes to the development of CHD, if PTSD and CHD share common pathways, or if CHD causes PTSD. Research combined across different disciplines suggests that prolonged or chronic stress does influence the development of CHD. A better understanding of the relationship will increase prevention and intervention efforts. Cardiologists may be most effective when they can recognize and manage emotional distress in practice.

Ambulatory cardiovascular activity and hostility ratings in women with chronic posttraumatic stress disorder

BACKGROUND

The objective of the current study is to evaluate the relationship between hostility and ambulatory cardiovascular activity in women with and without posttraumatic stress disorder (PTSD).

METHODS

One hundred and one women completed 24 hours of ambulatory monitoring and standardized diagnostic and hostility measures. Generalized estimating equations analysis was used to examine the effects of group and hostility factor scores (hostile beliefs, overt hostility, and covert hostility) on ambulatory heart rate (AHR) and ambulatory systolic (ASBP) and diastolic (ADBP) blood pressure.

RESULTS

After controlling for covariates, there was an interaction between PTSD and both hostile beliefs and overt hostility for AHR. Increases in hostility were associated with greater increases in heart rate among women with PTSD relative to those without PTSD. There was a similar interaction between hostile beliefs and group for ADBP.

CONCLUSIONS

Increased AHR and blood pressure have been linked to poor cardiovascular outcomes in nonpsychiatric populations. Individuals with PTSD display increased hostility, a construct that has also been linked to poorer cardiovascular outcomes. Increases in hostile beliefs were associated with a greater increase in ADBP among women with PTSD as compared with control subjects. These data suggest that PTSD might in part moderate the relationship between hostility and cardiovascular outcomes.

A prospective test of anxiety sensitivity as a moderator of the relation between gender and posttraumatic symptom maintenance among high anxiety sensitive young adults

The primary aim of this study was to evaluate the individual and combined influence of anxiety sensitivity (AS) and gender on the longitudinal prediction of posttraumatic symptoms. A large nonclinical sample of young adults (n=404) was prospectively followed over approximately 18 months. The primary findings indicated that gender and AS were uniquely associated with posttraumatic symptom levels during the follow-up period. Moreover, AS appeared more strongly (positively) related to posttraumatic stress symptoms during the follow-up period among females than males. These data provide novel prospective evidence regarding the interplay of relatively well-established risk factors implicated in the maintenance of posttraumatic stress symptoms.

Baroreceptor sensitivity at rest and during stress in women with posttraumatic stress disorder or major depressive disorder

The relationship between posttraumatic stress disorder (PTSD) and parasympathetic nervous system functioning was investigated during a baseline rest period and anger recall speaking task using noninvasive estimates of baroreceptor sensitivity. Participants (N = 124) were women categorized into one of four diagnostic groups: PTSD without major depressive disorder (MDD), PTSD with comorbid MDD, MDD without PTSD, and controls with neither psychiatric diagnosis. Women with PTSD (with or without MDD) exhibited significantly lower resting baroreceptor sensitivity than women not diagnosed with PTSD. Baroreceptor sensitivity decreased during the anger recall task, and the decrease was less among the psychiatric groups. Taken together, these findings suggest that PTSD is associated with reduced parasympathetic nervous system functioning.

Baroreflex mechanisms in major depression

BACKGROUND

Recent studies have shown that depressive disorder is associated with impaired baroreceptor or baroreflex sensitivity, which is proposed to be a predisposing factor for sudden death in patients with manifest cardiac disease. These studies have not evaluated the afferent and efferent components of the cardiac baroreflex loop or other baroreflex mechanisms that regulate target processes (cardiac metabolism and blood pressure variability) related to the impairment. The objective of this study was to gain more insight into autonomic functioning in depressive disorder to more fully examine the potential basis for increased cardiac mortality.

METHODS

The subjects were 28 women and men with unipolar major depression who were taking antidepressant medications and who were in partial remission and free of cardiovascular or other serious disease, and 28 healthy control subjects matched for sex, age, and ethnicity. The two samples were compared for negative affective dispositions (anger expression, hostility, defensiveness, anxiety), spontaneous (closed-loop) baroreflex activity, heart rate, heart rate variability, systolic blood pressure, and heart rate-systolic blood pressure double product under resting conditions.

RESULTS

Depressed patients showed a general disposition to anger suppression coupled with higher hostility and anxiety, and lower defensiveness. The patients showed higher general sympathetic activity (high levels of blood pressure, low-frequency heart rate variability) and lower parasympathetic-related activity (high heart rate and reduced high frequency heart rate variability) with affected cardiac metabolism estimated by the double product. Depressed patients had lower baroreflex sensitivity related to a higher gain of the afferent component of the baroreflex without respective gain adjustment of its efferent component (reflex gain 'de-afferentation'). It was coupled with a compensatory higher number of effective baroreflex reactions (reflex gating 're-afferentation'). Antidepressant agents and depressed mood had additional independent effects on baroreflex sensitivity through the efferent component of the cardiac baroreflex loop.

CONCLUSIONS

The data indicate that different baroreflex components and mechanisms may be impaired in patients with depression and may contribute to their increased cardiac risk.