Cardiac autonomic control buffers blood pressure variability responses to challenge: a psychophysiologic model of coronary artery disease

Selective breeding for an infant phenotype: rat pup ultrasonic vocalization (USV)

To examine processes underlying generational and developmental influences on anxiety, this laboratory produced two lines of (N:NIH strain) rats, selectively bred on the basis extreme rates of ultrasonic vocalization in 2 minutes of isolation at Postnatal Day 10. The research reviewed in this article focuses on: (1) establishment of the selectively bred lines; (2) defining infant behavioral and physiological phenotypes and (3) determining whether infantile USV phenotypes endure over development. The High and Low lines have diverged widely in their USV rates from each other and from the Random control line, which has maintained N:NIH strain rates overall from generation to generation. Beginning in the 11th generation, High USV pups have shown significantly higher frequencies of defecation and urination during isolation screening than the Low USV and random control line. Both lines show altered autonomic regulation of heart rates (HR) in response to stressors as juveniles and adults. These differences in HR responses in High and Low lines appear to be mediated by changes in the balance of sympathetic versus parasympathetic mechanisms. Other behavioral characteristics of the High line are consistent with an "anxious"/ "depressive" phenotype, such as vocalizations to touch in a novel environment, and performance in the Porsolt Swim, whereas Low line shows few differences in anxiety behavior. Future work will resolve the similarities and differences in the High and Low phenotypes and provide a developmental perspective to the growing body of information about affective regulation in humans and animals provided by selectively bred animal models.

Overcommitment to work is associated with changes in cardiac sympathetic regulation

OBJECTIVE

Work stress is associated with an increased risk for cardiovascular disease (CVD). Exaggerated cardiovascular reactivity to work-related stressors or incomplete recovery after work is a proposed mechanism underlying this increase in risk. This study examined the effects of work stress on 24-hour profiles of the pre-ejection period (PEP), a measure of cardiac sympathetic activity, obtained from ambulatory measurement of the impedance cardiogram.

METHODS

A total of 67 male white-collar workers (age 47.1 +/- 5.2) underwent ambulatory monitoring on 2 workdays and 1 non-workday. Work stress was defined according to Siegrist's model as 1) a combination of high effort and low reward at work (high imbalance) or 2) an exhaustive work-related coping style (high overcommitment).

RESULTS

High overcommitment was associated with shorter absolute PEP levels during all periods on all 3 measurement days, reduced wake-to-sleep PEP differences and reduced PEP variability, as indexed by the SD.

CONCLUSIONS

Overcommitment to work was associated with an increase in basal sympathetic drive and a reduction in the dynamic range of cardiac sympathetic regulation. Both findings are compatible with the hypothesis that overcommitment induces beta-receptor down-regulation.

Developmental, gender, and ethnic group differences in moods and ambulatory blood pressure in adolescents

BACKGROUND

Adolescence is characterized by profound changes in physical, psychological, and social functioning thought to be accompanied by intense and varying moods.

PURPOSE

Within a psychophysiological framework, this study examined the prevalence of 12 self-reported mood states of adolescents; investigated associations between specific mood states and ambulatory blood pressure readings; and explored effects of interactions among moods, gender, ethnic group, and maturation on ambulatory blood pressures.

METHODS

The sample included 371 African American, European American, and Hispanic American adolescents 11 to 16 years old. Systolic (SBP) and diastolic (DBP) blood pressures were measured every 30 min with an ambulatory monitor and were synchronized with electronic activity monitoring and moods self-recorded during waking hours in a checklist diary.

RESULTS

Moods differed significantly by gender, ethnic group, and maturation. Controlling for height, maturation, gender, ethnic group, mother's education, position, location, activity, other moods, and interactions of moods with other variables in a multilevel, random coefficients regression model, both positive and negative mood states were associated with higher levels of SBP and DBP; being relaxed or bored, or having a feeling of accomplishing things were associated with lower SBP and DBP. There were significant interaction effects of moods with physical maturity, gender, and ethnic group on ambulatory SBP and DBP.

CONCLUSIONS

Further study of the modifying effects of gender, ethnic group, and stage of development on reports of moods, and their associations with cardiovascular responses is recommended.

Alexithymia predicts attenuated autonomic reactivity, but prolonged recovery to anger recall in young women

Alexithymia has been prospectively associated with all-cause mortality and with cardiovascular morbidity. Here, stress-induced autonomic reactivity and recovery were examined as potential pathways linking alexithymia to cardiovascular disease. The relation of alexithymia to blood pressure, heart rate, and other cardiovascular parameters derived from impedance cardiography (N = 80) and heart rate variability (N = 40) was evaluated during rest, an anger recall task and recovery in women (ages 18-30). During anger recall, alexithymia was associated with significantly attenuated heart rate and stroke index reactivity, greater low frequency power, and with marginally dampened blood pressure and high frequency power reactivity. Overall, this response pattern suggests blunted sympathetic activation and diminished vagal withdrawal. Alexithymia was also related to slower diastolic blood pressure and quicker preejection period recovery implying abbreviated sympathetic arousal and possibly greater vagal modulation. These results impart some evidence for the hypoarousal model of alexithymia during reactivity, but the hyperarousal model during recovery. Autonomic dysregulation during and following acute emotional stress is suggested as a possible physiological pathway connecting alexithymia to cardiovascular disease.

Linear and nonlinear measures of blood pressure variability: increased chaos of blood pressure time series in patients with panic disorder

Arterial blood pressure (BP) variability increases progressively with the development of hypertension and an increase in BP variability is associated with end organ damage and cardiovascular morbidity. On the other hand, a decrease in heart rate (HR) variability is associated with significant cardiovascular mortality. There is a strong association between cardiovascular mortality and anxiety. Several previous studies have shown decreased HR variability in patients with anxiety. In this study, we investigated beat-to-beat variability of systolic and diastolic BP (SBP and DBP) in normal controls and patients with panic disorder during normal breathing and controlled breathing at 12, and 20 breaths per minute using linear as well as nonlinear techniques. Finger BP signal was obtained noninvasively using Finapres. Standing SBPvi and DBP BPvi (log value of BP variance corrected for mean BP divided by HR variance corrected for mean HR) were significantly higher in patients compared to controls. Largest Lyapunov exponent (LLE) of SBP and DBP, a measure of chaos, was significantly higher in patients in supine as well as standing postures. The ratios of LLE (SBP/HR) and LLE (DBP/HR) were also significantly higher (P<.001) in patients compared to controls. These findings further suggest dissociation between HR and BP variability and a possible relative increase in sympathetic function in anxiety. This increase in BP variability may partly explain the increase in cardiovascular mortality in this group of patients.

Twenty-four-hour ambulatory assessment of heart rate and blood pressure in chronic PTSD and non-PTSD veterans

This study examined 24-hr levels of ambulatory heart rate (HR) and blood pressure (BP) in 2 groups of male veterans: 19 with chronic posttraumatic stress disorder (PTSD) and 17 who never met criteria for PTSD. The relationships between diagnostic status, basal cardiovascular activity, and cardiovascular reactivity to stress were examined. Hierarchical linear modeling analyses revealed that the PTSD group had higher resting HR than the non-PTSD group. Moreover, the PTSD group showed greater BP reactivity during times of affective distress than the non-PTSD group. The health care implications of these findings are discussed, as are directions for future research.

Differential analysis in the time domain of the baroreceptor cardiac reflex sensitivity as a function of sequence length

Analysis of baroreceptor sensitivity (BRS) in the time domain through the spontaneous sequence method used a measure of BRS based on the average of all sequences detected, without making any distinction in cardiac cycle length. In this article, we study differentially the functioning of the baroreflex as a function of the length of the cardiac sequences (3, 4, 5, or 6 cardiac cycles). One hundred and four students performed three mental stress tasks: mental arithmetic, memory, and visual attention. The results show that (1) as sequence length decreases, the relationships between BRS and indexes of vagal cardiac control increase, (2) the BRS associated with the more short sequences (3 and 4 beats) is the most vulnerable to mental stress, particularly the mental arithmetic task, and (3) BRS increases progressively as sequence length decreases. These results suggest that the nature and functioning of the baroreflex differ as a function of the length of the cardiac sequences.

Is depression a major risk factor for coronary disease? A systematic review of the epidemiologic evidence

My objective is to examine systematically the status of the current evidence for and against depression as an independent major risk factor for coronary disease. From English-language reports on depression and coronary disease in MEDLINE (1966-2002) and PsycINFO (1967-2002), and from informal searches, I selected all studies that addressed the specific questions related to the established criteria for risk-factor status: (1) strength of association, (2) prediction, (3) specificity, (4) consistency, (5) dose-response effect, (6) biological plausibility, and (7) response to treatment. I find that the evidence for depression as a coronary disease risk factor is good for four criteria: strength of association, prediction, consistency, and dose-response effect. The evidence on specificity and biological plausibility is fair. Due to the lack of definitive studies, there is currently insufficient evidence for cardiac risk reduction in response to treatment for depression. My conclusion is that the evidence for depression's role as an independent major risk factor for coronary disease is good in four areas, but not yet conclusive in three, pointing to the need for three types of studies: (1) prospective, observational studies that address specificity questions, (2) studies of biological mechanisms linking depression and coronary disease, and (3) clinical trials of treatments for depression in people with coronary disease or at high risk for developing coronary disease.

Low respiratory sinus arrhythmia and prolonged psychophysiological arousal in posttraumatic stress disorder: heart rate dynamics and individual differences in arousal regulation

BACKGROUND

There is extensive evidence that the parasympathetic branch of the autonomic nervous system can modulate psychophysiological arousal. To date, no studies have investigated associations between cardiac vagal tone and the time course of arousal during exposure to trauma-related stimuli in posttraumatic stress disorder (PTSD).

METHODS

Thirty-one subjects, 29 with PTSD and 2 with partial PTSD, had electrocardiograms recorded during baseline and 2-minute traumatic and neutral script-driven imagery periods. Heart rate, respiratory sinus arrhythmia (RSA), and heart rate half-recovery to the trauma script were quantified, and subjects were divided into low and high baseline RSA groups.

RESULTS

Across all participants, heart rate significantly increased from the neutral to the trauma script and RSA significantly decreased from baseline to trauma script (p < .05). As predicted, low RSA subjects had more prolonged heart rate increases to the trauma script than high RSA subjects (p < .001), and heart rate half-recovery was negatively correlated to baseline RSA (r = -.50, p =.005).

CONCLUSIONS

This study is the first to find decreased RSA in response to a traumatic reminder and an association between low baseline RSA and sustained conditioned arousal in PTSD. Low vagal tone may account for deficient arousal and emotion regulation capacities often observed in PTSD.

Cardiovascular reactivity to mental arithmetic and cold pressorin African Americans, Caribbean Americans, and white Americans

BACKGROUND

Caribbean Americans and African Americans, two of the largest Black ethnic groups in the United States, differ in cardiovascular-disease-related mortality rates.

PURPOSE

Cardiovascular reactivity to psychological stress may be an important marker or mediator of risk for cardiovascular disease development in Blacks in the United States, yet little attention has been paid to ethnicity among Blacks in reactivity research. This study examined cardiovascular reactivity to psychological stress in African American, Caribbean American, and White American participants.

METHODS

Forty-five women and 43 men performed mental arithmetic and hand cold pressor (CP) tasks.

RESULTS

Caribbean Americans displayed larger decreases in heart period variability during mental arithmetic than White Americans (p =.02). White Americans exhibited a pre-ejection period decrease, whereas African Americans and Caribbean Americans displayed pre-ejection period increases during CP (p =.023). African Americans exhibited greater decreases in interbeat interval during CP than White Americans (p =.013). Caribbean Americans displayed greater decreases in cardiac output than White Americans during CP (p =.009). White Americans exhibited significantly greater increases in systolic blood pressure than Caribbean Americans during CP (p =.014).

CONCLUSIONS

These findings suggest that differences in reactivity to psychological stress exist among Black ethnic groups in the United States and underscore the need to consider ethnicity as a factor in reactivity research with Black Americans.

Vital exhaustion as a risk factor for ischaemic heart disease and all-cause mortality in a community sample. A prospective study of 4084 men and 5479 women in the Copenhagen City Heart Study

BACKGROUND

Vital exhaustion, a psychological measure characterized by fatigue and depressive symptoms, has been suggested to be an independent risk factor for ischaemic heart disease (IHD) but the generality of the phenomenon remains in question. The aim of this study is to describe prevalence of these symptoms in a community sample and determine whether they prospectively predict increased risk of IHD and all-cause mortality in men and women.

METHODS

The study base was 4084 men and 5479 women aged 20-98 free of IHD examined in 1991-1993 in the Copenhagen City Heart Study. Events were ascertained through record linkage until 1998 for IHD and September 2000 for all-cause mortality. There were 483 first hospital admissions and deaths caused by IHD and 1559 deaths from all causes during follow-up.

RESULTS

The 17 items on the vital exhaustion questionnaire were frequently endorsed with prevalence ranging from 6 to 47 per cent, higher in women. All but 4 of the 17 items were significantly associated with IHD with significant relative risks (RR) ranging between 1.36 (95% CI: 1.08, 1.72) and 2.10 (95% CI: 1.63, 2.71). Associations with all-cause mortality were also observed, but were weaker. RR of both IHD and all-cause mortality increased with increasing item sum score and were similar in men and women. For IHD, RR reached a maximum of 2.57 (95% CI: 1.65, 4.00) for subjects endorsing >9 items. The similar RR for all-cause mortality was 2.50 (95% CI: 2.09, 2.99). Multivariate adjustment for biological, behavioural, and socioeconomic risk factors did not substantially affect the association for IHD but attenuated the association with all-cause mortality.

CONCLUSIONS

Measures of fatigue and depression were common symptoms in this population sample and convey increased risk of IHD and of all-cause mortality. We propose this knowledge begin to be implemented in risk assessment in clinical practice.

Hostility, interpersonal interactions, and ambulatory blood pressure

OBJECTIVE

This study examined aspects of the transactional model of hostility and health by investigating relationships among hostility, interpersonal interactions, and ambulatory blood pressure in a healthy community sample.

MATERIALS AND METHODS

Participants included 65 female and 39 male healthy adults between the ages of 18 and 46 years. Ambulatory blood pressure (ABP) and diary data on mood and social interactions were obtained every 20 minutes for 1 day. Mixed models regression analyses were used to evaluate the relationships among hostility, interpersonal interactions, and ABP.

RESULTS

Trait hostility was positively associated with the frequency and intensity of negative interactions and was negatively associated with the frequency and intensity of positive interactions. Interacting with others was associated with increases in systolic blood pressure (SBP) and diastolic blood pressure (DBP). The magnitude of the increase in blood pressure was positively associated with the degree to which the interaction was perceived as negative. Hostility was not directly associated with ABP/heart rate (HR) or ABP/HR responses during any interactions or negative interactions. However, there was an interaction between hostility and negative interaction intensity for DBP, suggesting that hostility moderates the effects of negative interactions on DBP. Specifically, increases in the intensity of negative interactions were associated with increases in DBP for participants with high, but not low, hostility.

CONCLUSIONS

The results provide partial support for the notion that hostility may be associated with risk for cardiovascular disease through its effects on interpersonal interactions and their cardiovascular correlates.

Autonomic responses to psychological stress: The influence of menopausal status

Cardiovascular disease is the leading killer of women in developed countries. Menopause, stress, and lack of social support may contribute to the increased risk of heart disease morbidity and mortality in women. This study examined the effects of psychological stress and social support on autonomic nervous system control of the heart in 18 pre- and 34 postmenopausal women. Autonomic activity, as indexed by high-frequency heart rate variability and pre-ejection period, was assessed at rest and during a public speech task. Social support was determined using the Berkman Social Support Inventory. Postmenopausal women had higher heart rate (F = 4.4, p pound.04) and less parasympathetic activity (F = 11.9, p pound.001) compared with premenopausal women at rest. In response to stress, sympathetic nervous system activity increased in postmemopausal women (F = 6.1, p pound.02); however, this effect was no longer significant when age was used as a covariate in the analysis. Social support did not significantly affect measures of autonomic activity in either the pre- or postmenopausal women. Postmenopausal women have greater sympathetic and less parasympathetic activity than premenopausal women, which may account for their increased risk of coronary artery disease.

Anxiety and hostility are associated with reduced baroreflex sensitivity and increased beat-to-beat blood pressure variability

OBJECTIVE

The purpose of this study was to determine whether psychological factors are associated with heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) among healthy middle-aged men and women.

METHODS

A population-based sample of 71 men and 79 women (35-64 years of age) was studied. Five-minute supine recordings of ECG and beat-to-beat photoplethysmographic finger systolic arterial pressure and diastolic arterial pressure were obtained during paced breathing. Power spectra were computed using a fast Fourier transform for low-frequency (0.04-0.15 Hz) and high-frequency (0.15-0.40 Hz) powers. BRS was calculated by cross-spectral analysis of R-R interval and systolic arterial pressure variabilities. Psychological factors were evaluated by three self-report questionnaires: the Brief Symptom Inventory, the shortened version of the Spielberger State-Trait Anger Expression Inventory, and the Toronto Alexithymia Scale.

RESULTS

Psychological factors were not related to HRV. Anxiety was associated with decreased BRS (p = 0.001) and higher low-frequency (p = 0.002) power of systolic arterial pressure variability. These associations were independent of age, gender, other psychological factors, heart rate, and systolic and diastolic blood pressures. Hostility was an independent correlate of increased low-frequency power of diastolic arterial pressure (p = 0.001) and increased high-frequency power of systolic arterial pressure (p = 0.033) variability.

CONCLUSIONS

Anxiety and hostility are related to reduced BRS and increased low-frequency power of BPV. Reduced BRS reflects decreased parasympathetic outflow to the heart and may increase BPV through an increased sympathetic predominance.

Cardiovascular reactivity of Singaporean male police officers as a function of task, ethnicity and hostility

OBJECTIVE

This research examined hemodynamic processes in cardiovascular reactivity (CVR) as a function of task, ethnicity and trait hostility.

METHOD

One hundred and fourteen male patrol officers from the Singapore Police Force participated in this experimental study. Trait hostility was measured using the interpersonal hostility assessment technique to derive a hostile behavior index (HBI). Heart rate, blood pressure and hemodynamic measures were taken while participants performed three tasks: mental arithmetic, number reading and anger recall (AR).

RESULTS

AR elicited the greatest blood pressure, vascular and cardiac output reactivity. HBI scores were positively related to systolic blood pressure reactivity during AR for Malays whereas this was not true for Indians and Chinese. Across tasks Indians with high HBI scores appeared to be cardiac reactors whereas the reactivity patterns for Malays and Chinese were undifferentiated. Self-report of negative mood was not related to CVR.

CONCLUSION

These results are consistent with the higher rates of coronary heart disease deaths among Indians as well as the higher rates for hypertension among Malays in Singapore.

Do depressive symptoms increase the risk for the onset of coronary disease? A systematic quantitative review

OBJECTIVE

The objectives of this study were to systematically review the recent studies of the contribution of depression to the onset of coronary disease and to estimate the magnitude of the risk posed by depression for onset of coronary disease.

METHOD

We searched MEDLINE (1966-2000), PsychInfo (1967-2000), and cross references and conducted informal searches for all community studies of depression symptoms in samples with no clinically apparent heart disease at baseline. From these studies we selected all published cohort studies of 4 years or more follow-up that controlled for other major coronary disease risk factors and reported relative risks (or a comparable measure) of baseline depression for the onset of coronary disease. Following methods for the meta-analysis of epidemiologic studies, we used a random-effects model to estimate the combined overall relative risk.

RESULTS

Ten studies met our inclusion criteria. Relative risks ranged from 0.98 to 3.5. Nine studies reported significantly increased risk, including two with mixed results; one study reported no increased risk. The combined overall relative risk of depression for the onset of coronary disease was 1.64 (95% CI = 1.41-1.90).

CONCLUSIONS

This quantitative review suggests that depressive symptoms contribute a significant independent risk for the onset of coronary disease, a risk (1.64) that is greater than the risk conferred by passive smoking (1.25) but less than the risk conferred by active smoking (2.5). Future prospective community studies should examine the effect of severity and duration of depressive symptoms and disorders on the risk for the onset of coronary disease.

Posttraumatic stress disorder, hostility, and health in women: a review of current research

A large body of evidence indicates that hostility is related to increased morbidity and mortality and evidence is growing that posttraumatic stress disorder (PTSD) is associated with poorer health outcomes. The majority of this research, however, has been conducted in male samples. As a result, the connections between PTSD and hostility and the ramifications of these variables on health in women are less clear. We review the current literature examining PTSD, hostility, and health in women and discuss possible mechanisms underlying the relationship between PTSD and hostility on health outcomes in the context of a proposed theoretical model. Although the current literature suggests that hostility and PTSD are related to health in women, more rigorous, focused research is lacking. A number of suggestions for future research are provided.

Mindfulness meditation, anxiety reduction, and heart disease: a pilot study

Heart disease is the leading cause of death among Americans each year, yet the misperception still exists that cardiovascular disease is not a serious health problem for women. Evidence indicates that anxiety contributes to the development of heart disease. The primary purpose of this study was to assess the effectiveness of Kabat-Zinn's mindfulness-based stress reduction program to reduce anxiety in women with heart disease. Anxiety, emotional control, coping styles, and health locus of control were compared in a treatment and control group of women with heart disease. Post-intervention analyses provide initial support for beneficial effects of this program.

Dissociated autonomic regulation during stress and physical complaints

OBJECTIVE

In order to evaluate the relevance of individual differences in the regulation of autonomic subsystems to psychosomatic processes, reactivity of the autonomic nervous system to an emotional stressor was related to the occurrence of physical complaints. In contrast to most other studies, the measures were related to the degree of actually experienced stress.

METHODS

In a large sample (n=111), electrodermal activity (EDA) and heart rate variability (HRV) were obtained at rest and during emotional stress. Physical complaints were assessed by a standardized symptom checklist providing subscales for different physiological systems.

RESULTS

Subjects who were actually stressed by the stress induction procedure but showed only weak reactivity of EDA, and subjects who were only slightly stressed but showed a marked EDA response reported a high amount of gastrointestinal complaints. A greater decrease of high-frequency HRV from the rest to the stress condition was associated with reports of relatively more cardiovascular complaints.

CONCLUSION

Findings indicate that the link between regulation of EDA and gastrointestinal functions has to be localized in higher brain structures and support the hypothesis that minor autonomic dysregulation may represent one pathway linking negative affect and the development of physical disorders.

Posttraumatic stress disorder in women: assessment and treatment in primary care

The focus of this article is to provide primary care clinicians with a better understanding of women who have undergone sexual trauma and have related post-traumatic stress disorder. Victimization has adverse physical and mental health effects and affects a woman's clinical presentation, her coping skills, and the primary care intervention strategies needed to treat her. The article reviews issues of victimization and related PTSD among women, including the prevalence and sequel of victimization, and provides a theoretical framework for primary care intervention, treatment, and referral.

Cardiovascular indices of peripheral and central sympathetic activation

OBJECTIVE

A number of sympathetic nervous system (SNS) parameters have been used in cardiovascular psychophysiology. This study aimed to describe the pattern and redundancy of a set of SNS parameters during peripherally induced changes of cardiac sympathetic activation and reflex modulation of central SNS control. Preejection period (PEP) was assessed as a marker of peripheral sympathetic activation. Low-frequency blood pressure variability (BPV) was assessed as an estimate of central SNS control.

METHODS

Peripheral beta-sympathetic stimulation and blockade were achieved with epinephrine and esmolol hydrochloride (beta1-blockade), respectively. Changes in central SNS output were induced by loading and unloading arterial baroreceptors with norepinephrine and nitroprusside sodium, respectively. This single-blinded, crossover study in 24 healthy men also included two placebo control periods. PEP was derived from impedance cardiography and adjusted individually for heart rate. BPV was calculated by power spectral analyses of beat-to-beat heart rate and systolic blood pressure (Finapres system) data.

RESULTS

PEP decreased during epinephrine infusion (-40.1 +/- 3.8 ms, p <.0001) and increased during esmolol infusion (+6.6 +/- 3.5 ms, p =.05). PEP was shortened after central SNS activation by nitroprusside (-16.8 +/- 2.9 ms, p < 0.0001). Systolic BPV in the low-frequency range (0.07-0.14 Hz, Mayer waves) increased during nitroprusside infusion (+0.44 +/- 0.19 ln mm Hg(2), p =.03) and decreased during norepinephrine infusion (-0.67 +/- 0.13 ln mm Hg(2), p < 0.0001). Low-frequency BPV did not change significantly during epinephrine or esmolol infusion.

CONCLUSIONS

Our data provide empirical evidence of separable peripheral and central sympathetic response components. The combined report of low-frequency BPV and PEP gives distinct information on both central SNS control and the level of sympathetic cardiac activation achieved.

Predictors of cardiac patients' psychophysiological responses to caregiving

Patients who are hospitalized for treatment of cardiac problems are at risk from life-threatening cardiovascular changes related to autonomic nervous system (ANS) arousal. Physical care during hospitalization can increase ANS arousal, yet caregiving is an essential feature of patient treatment. The purpose of this study was to identify the degree to which a patient's vulnerability to sensory stimuli, perceptions of previous caregiving and stressful events during hospitalization may contribute to ANS arousal during caregiving. Fifty-nine patients, who were hospitalized for treatment of coronary artery or valvular disease, received a standardized protocol designed to simulate aspects of physical caregiving. Heart rate, incidence of arrhythmias, blood pressure and state anxiety were measured during the protocol to determine ANS arousal. Regression analyses provided evidence that sensory vulnerability was the most consistent predictor across all indices of arousal during caregiving. Previous caregiving experiences that were perceived as 'negative' by the patient also contributed to higher blood pressure and anxiety. Stressful hospital events involving the family predicted higher blood pressure during caregiving.

Hostility, gender, and cardiac autonomic control

OBJECTIVE

Although considerable evidence implicates hostility in the development of coronary artery disease (CAD), the pathogenic mechanisms remain poorly understood. We have developed a psychophysiological model that holds that altered autonomic nervous system function links psychological traits with CAD outcomes. In laboratory studies, stressors reduce high-frequency (HF) heart period variability, an index of cardiac vagal modulation. With ambulatory electrocardiographic recording, we demonstrated in a predominantly male sample that hostility was inversely associated with HF power, but only during waking hours. These findings are consistent with the hypothesis that hostile individuals experience multiple stressful interpersonal transactions each day, resulting in overall lower HF power during the day but not at night.

METHODS

To further evaluate this hypothesis, we screened 96 subjects using the Cook-Medley Hostility Scale and selected 15 men and 15 women representing a wide distribution of hostility. These subjects were studied in a laboratory session assessing reactivity to psychological and orthostatic challenges with continuous electrocardiographic, blood pressure, and respiration monitoring. We predicted that for men and women, hostility would be inversely related to reductions in HF power in response to challenge.

RESULTS

In response to mental stressors, all measures of heart period variability change were inversely related to hostility as predicted. No such relationships were found for responses to tilt. The data suggested a possible effect of gender on these relationships.

CONCLUSIONS

These data add to the growing body of evidence showing that hostility influences vagal modulation of the cardiovascular system and suggest that altered autonomic control is a pathogenic mechanism linking hostility and CAD.

Sustained anxiety and 4-year progression of carotid atherosclerosis

Several studies have shown that anxiety disorders are associated with a higher risk of coronary artery disease. However, the relationship between anxiety disorders and atherosclerosis has been studied to a lesser extent. The goal of this study was to examine whether high and stable trait anxiety was associated with the progression of atherosclerosis. The study group consisted of 726 subjects (297 men and 429 women), aged 59 to 71 years, recruited from the electoral rolls of the city of Nantes. The subjects had no history of coronary artery disease at baseline evaluation and or at the 2-year follow-up. Two follow-up examinations were conducted 2 and 4 years after the baseline evaluation. Trait anxiety was evaluated by means of the French translation of the Spielberger Inventory (a 20-item trait inventory, form X-2). The "sustained anxiety" group consisted of men and women with the highest Spielberger Inventory scores at baseline and at the 2-year follow-up examination. Each ultrasound examination included measurement of intima-media thickness and the sites of plaque in the extracranial carotid arteries. Men with sustained anxiety showed a higher 4-year increase of common carotid intima-media thickness than did men without sustained anxiety (adjusted means 0.08 versus 0.04 mm, respectively; P=0.05) and a higher risk of 4-year plaque occurrence (adjusted OR 3.5, 95% CI 1.4 to 8.5). Among women, sustained anxiety was associated with a higher 4-year increase of common carotid intima-media thickness (0.07 versus 0.04 for women with versus women without sustained anxiety, respectively; P=0.07). These results suggest that chronically high levels of anxiety may contribute to accelerating the evolution of carotid atherosclerosis.

Psychological factors associated with coronary heart disease

Objectives: Psychological coronary-proncncss is most probably one of the first recognised risk factors for coronary heart disease (CHD). The mechanisms by which psychological risk factors might exert their influence on the cardiovascular system arc less clear than those for the more standard biological risk factors. The aim of this review was to classify all possible mechanisms of potentiation of CHD by psychological factors.

Method: A MEDLINE search was conducted by selecting literature on both standard biological risk factors (eg. dyslipidaemia, hypertension, smoking) and psychological risk factors (eg. personality traits, behavioural characteristics, coping with stress) for CHD.

Results: It was suggested that six biological mechanisms could mediate psychological influences specifically for CHD, of course, together with the seventh mechanism of general alterations in health-related behaviours. These are: increased oxygen demand of the heart muscle, decreased blood supply to the heart muscle, increased concentration of blood, enhanced blood clotting, increase in cholesterol and other plasma lipids, disturbances of blood sugar level, and alterations in health-related behaviours.

Conclusions: If more studies of CHD were conducted with both physical and psychological risk factors simultaneously, it would be possible to investigate which of the above suggested mechanisms are important, which could in turn substantially improve both primary and secondary preventive measures.

Heart rate variability in depressive and anxiety disorders

Loss of normal autonomic nervous system control of heart rate and rhythm is an important risk factor for adverse cardiovascular events. After myocardial infarction, reduction in beat-to-beat heart rate variability, a measure of cardiac autonomic innervation by the brain, is a strong predictor of death. With loss of vagal innervation, as is noted in patients with severe neuropathy and in heart transplant recipients, there is loss of heart rate variability. It is speculated that decreased parasympathetic innervation exposes the heart to unopposed stimulation by sympathetic nerves. Individuals with high hostility scores and patients with anxiety or depressive disorders have low heart rate variability and may be at increased risk for cardiovascular death associated with coronary heart disease and arrhythmias. After myocardial infarction, depressed patients exhibit higher mortality rates compared with nondepressed patients. Men with "phobic anxiety," a construct that appears to overlap substantially with panic disorder, also have higher rates of sudden cardiac death and coronary artery disease than control populations. The reduction in autonomic nervous system control to the heart may be one link between psychopathology and heart disease. Although tricyclic antidepressants reduce heart rate variability, at least one study has suggested that, in patients with panic disorder, treatment with the selective serotonin reuptake inhibitor paroxetine normalizes heart rate variability. Hence there is potential for the treatment of psychiatric disorders to affect positively the development and course of cardiovascular disease.

The relationship between depression and cardiovascular disorders

Expanding scientific evidence supports a long-recognized link between cardiovascular disease and depression. As an independent risk factor, depression increases patient vulnerability to both cardiac events and mortality. Several important pathophysiologic mechanisms have been proposed, including hypothalamic-pituitary axis hyperactivity, autonomic nervous system dysfunction, and increased platelet reactivity, among others. The recently completed Sertraline Antidepressant Heart Attack Randomized Trial (SADHART) inaugurates a series of studies intended to address the impact of antidepressant therapy on cardiovascular risk.

Cerebral activation, hostility, and cardiovascular control during mental stress

OBJECTIVE

Hostility has been established as a risk factor for the development of coronary artery disease. Putatively pathogenic hemodynamic and neuroendocrine responses to psychological stressors are associated with hostility, but the cerebral effects of hostility and their relationship to these responses are unknown. This pilot study examined cardiovascular and cerebral blood flow responses to stress in subjects with high and low levels of trait hostility.

METHODS

Regional cerebral blood flow was measured by single-photon emission computed tomography (SPECT) during a control condition and in response to mental arithmetic stress.

RESULTS

The stressor was associated with reduced blood flow to the prefrontal cortex, and this reduction was greater in the high hostility subjects.

CONCLUSION

These preliminary findings support the hypothesis that mental arithmetic stress is associated with reduced blood flow to prefrontal cortex, and that trait hostility is associated with a stronger effect.

Cardiovascular pathways: socioeconomic status and stress effects on hypertension and cardiovascular function

In westernized societies there is a consistent and continuous gradient between the prevalence of cardiovascular disease (including both coronary heart disease and stroke) with SES, such that people from lower SES have more disease. Several studies have examined the roles of the major cardiovascular risk factors for explaining this gradient. There is a strong SES gradient for smoking, which parallels the gradient in disease, but the gradients for hypertension and cholesterol are weak or absent. Central obesity and physical inactivity may also be contributory factors. In the United States there is a strong association between SES and race, and it is suggested that the higher prevalence of hypertension and cardiovascular disease in blacks may be attributed to psychosocial factors, including those related to SES. The possible pathways by which SES affects cardiovascular disease include effects of chronic stress mediated by the brain, differences in lifestyles and behavior patterns, and access to health care. At the present time, the second of these is the strongest candidate; the effects of stress have been little studied.