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Biomedical subjects

P Grossman

Publications and source records attributed to P Grossman.

At least 37 records · Page 2Linked to original sources
PubMed1992

Cardiac autonomic mechanisms associated with borderline hypertension under varying behavioral demands: evidence for attenuated parasympathetic tone but not for enhanced beta-adrenergic activity.

Elevated blood pressure in psychophysiological studies of borderline hypertension is frequently attributed to the effects of increased sympathetic tone, and with few exceptions, the potential parasympathetic contributions have not been considered. Furthermore, of the investigations that have addressed vagal influences upon blood pressure, most have employed invasive pharmacological assessment of parasympathetic tone. In this study, cardiac parasympathetic and beta-adrenergic influences in borderline hypertension were evaluated noninvasively employing respiratory sinus arrhythmia as a vagal index and preejection period as a sympathetic index of cardiac functioning. Subjects were 30 borderline hypertensive and 23 normotensive males (age range, 24-45 years). The ECG, blood pressure, impedance cardiography, and respiration were measured during two baselines (initial and post-task), a memory-comparison reaction time task, the cold pressor, and CO2-rebreathing. Results indicated tonic differences between groups in all cardiovascular variables across tasks, with the exception of pre-ejection period, which showed no group effects at all. Hypertensives additionally manifested somewhat heightened systolic blood pressure reactivity and attenuated cardiac parasympathetic responsivity to specific tasks. Our findings provide no support for an exaggerated cardiac beta-adrenergic tonic level or reactivity in borderline hypertensives. On the other hand, the consistently lower magnitude of respiratory sinus arrhythmia in our hypertensives suggests that reduced parasympathetic control may be involved in the pathophysiology of hypertension.

Adult↗
PubMed1991

Prediction of tonic parasympathetic cardiac control using respiratory sinus arrhythmia: the need for respiratory control.

Respiratory sinus arrhythmia (RSA) has received much attention in recent years due to the large body of evidence indicating that variations in this phenomenon represent alterations in parasympathetic cardiac control. Although it appears that respiratory sinus arrhythmia is mediated by vagal mechanisms, the extent to which the well-known respiratory influences (i.e., rate and tidal volume) on respiratory sinus arrhythmia (in altering its magnitude) may moderate the relationship between RSA and cardiac vagal tone has never been systematically studied. We addressed this issue by examining intraindividual relationships among RSA magnitude, respiration (rate and tidal volume), and heart period among six healthy male adults after intravenous administration of 10 mg propranolol, a beta-adrenergic blocker. Subjects were exposed to various behavioral tasks which altered all physiological variables measured. Variations in heart period after beta blockade were assumed to be predominantly vagally mediated. Within-subject regression analyses consistently showed that respiratory parameters influenced RSA magnitude, but not tonic variations in beta-blocked heart period, suggesting that respiratory-mediated RSA alterations are not associated with changes in cardiac vagal tone. Only when respiratory variables were statistically controlled was there evidence of a reasonable correspondence between beta-blocked heart period and RSA amplitude, providing support for the idea that respiratory parameters need to be controlled when using RSA amplitude as an index of cardiac vagal tone. Repeated-measures analyses of variance of mean levels of heart period and respiratory sinus arrhythmia across subjects supplemented and supported the intraindividual results. These findings point to the importance of controlling for respiratory parameters when using respiratory sinus arrhythmia as a cardiac vagal index.

Adult↗
PubMed1991

A model of cardiovascular activation components for studies using autonomic receptor antagonists.

Alpha-adrenergic, beta-adrenergic, and cholinergic responses are often considered important activation components when conceptual and empirical analyses are made of single physiological variables and of patterns of cardiovascular reactivity; these autonomic distinctions are also of particular significance in autonomic blockade studies. A Model of Cardiovascular Activation Components is introduced that relates these components to both the measured cardiovascular variables and the protocol of autonomic blockade studies. It is pointed out that a restricted form of the complete model is often implicitly used in cardiovascular psychophysiology. The differential consequences of an erroneous employment of the restricted model are discussed for single and dual blockade protocols. Critical evaluations of autonomic blockade as a tool in cardiovascular psychophysiology are examined and are proposed to be often the consequence of the restricted model assumptions. Lastly, the utility of the Activation Components Model for a componential description of tasks and for componential intertask relationships is illustrated with data from the literature.

Arousal↗
PubMed1990

Paced respiratory sinus arrhythmia as an index of cardiac parasympathetic tone during varying behavioral tasks.

This study addresses a number of unresolved issues regarding the employment of respiratory sinus arrhythmia as an index of tonic parasympathetic cardiac control in psychophysiological investigations. These questions include the following: (1) Does respiratory sinus arrhythmia reflect cardiac vagal tone under conditions in which alterations in parasympathetic control are expected to be mild to moderate? (2) Are variations in human respiratory sinus arrhythmia that occur in response to varying behavioral demands independent of beta-adrenergic effects on the heart? (3) To what extent do typical experimental tasks apparently affect tonic cardiac vagal control? Twelve healthy male subjects were administered a joint alpha- and beta-adrenoreceptor pharmacological blocker on one day and a placebo on another (balanced across subjects). On both days, respiratory sinus arrhythmia and heart period were monitored during a number of different experimental tasks while subjects continuously paced their respiration. Results indicated that respiratory sinus arrhythmia, under controlled respiratory conditions, is uninfluenced by variations in sympathetic activity, and provides a reasonably sensitive index of cardiac vagal tone, even when alterations in parasympathetic tone are not large. Furthermore, our findings suggest that cardiac vagal tone is responsive to varying behavioral demands and may interact in different ways with beta-adrenergic mechanisms.

Adult↗
PubMed1990

A comparison of three quantification methods for estimation of respiratory sinus arrhythmia.

The empirical literature has shown that respiratory sinus arrhythmia is a sensitive noninvasive index of parasympathetic cardiac control. Nevertheless there has been no general agreement among investigators as to the most preferable quantification technique for assessing respiratory sinus arrhythmia, although there has been much speculation that specific estimation techniques are more or less reflective of vagal processes and could be more or less contaminated by other influences upon heart period variability unrelated to respiration. This study compared three quantification procedures for estimating respiratory sinus arrhythmia (RSA): (1) a spectral analytic technique, (2) a complex detrending approach removing periodic and aperiodic cardiac variations unrelated to respiration, and (3) a time-domain, peak-valley procedure employing inspiratory and expiratory periods as windows for determining range of cardiac-interval fluctuations associated with respiratory phase. Measures derived from these techniques were intra- and interindividually compared using three different samples of male subjects, including students, adult normotensives, and adult hypertensives. All interindividual correlations between measures yielded coefficients above .92 and the mean within-subject correlation across 42 individuals was .96, thus indicating a marked degree of comparability between measures. Additionally, given that much evidence indicates lawful within-individual relations between RSA amplitude and respiratory parameters, we employed respiratory period as an external criterion and compared intraindividual correlations between this variable and (2) and (3); results showed that (3) was significantly more highly associated with respiration than was (2), although the mean r's for the two measures did not diverge greatly (.91 vs. .84). Finally, inspection of the data and further regression analyses did not suggest that any of the RSA estimates were differentially contaminated by other components of cardiac variability. Our findings suggest that the three techniques are almost equivalent as indices of cardiac vagal tone and would appear to ease concerns about the inferiority of any of the procedures. Choice of a quantification procedure should therefore be tailored to the specific empirical needs of an investigation. The advantages and disadvantages of each method are discussed.

Adult↗
PubMed1986

Depressive symptoms and life events in physically ill hospitalized adolescents.

To study life events and depressive symptoms in adolescents hospitalized for physical illness, we administered the Coddington Life Events Survey and the Beck Depression Inventory (BDI) to 43 acutely ill adolescents, 42 chronically ill adolescents, and 140 adolescents from a general population. There were no differences between the three groups in total BDI, Psychological BDI, and Coddington Life Change Categories adjusted for hospitalization. The Somatic BDI was significantly greater in the acutely ill and chronically ill than in the general population sample (p less than 0.01). In the chronically ill, the Family Life Change score correlated with the psychological BDI (r = 0.44, p less than 0.01) but the Undesirable Life Change score did not. In the acutely ill and the general population, the Undesirable Life Change Score correlated with the Psychological BDI (r = 0.44, p less than 0.01), (r = 0.43, p less than 0.01) but the Family Life Change Score did not.

Acute Disease↗
PubMed1985

A controlled study of a breathing therapy for treatment of hyperventilation syndrome.

A therapy directed toward slowing and regularizing the ventilatory pattern was compared with a partial-treatment, comparison procedure for individuals with somatic and psychological symptoms attributable to hyperventilation episodes (i.e. hyperventilation syndrome). Comparing repeated measures between a pretreatment baseline session and a post-treatment followup, we found that the experimental therapy, in contrast to the comparison procedure, produced a greater number of, and more extensive, improvements in psychological, symptom complaint and ventilatory dimensions. Results also suggest changes in central respiratory control mechanisms as a consequence of treatment.

Adult↗
PubMed1984

Diagnosis of hyperventilation syndrome on the basis of reported complaints.

Four hundred consecutive patients referred for diagnosis of hyperventilation syndrome were studied to assess the utility of self-reported complaints for making primary diagnoses of the syndrome. One-half of the subjects were unequivocally diagnosed as positive for the disorder, the other half as negative. This diagnosis was determined by the presence or absence of two criteria with established validity: (a) recognition of major presenting symptoms during a period of voluntary hyperventilation, and (b) slow return of end-tidal CO2 levels to pre-hyperventilation baseline values after the voluntary period of overbreathing. Analyses focused on differences in presenting symptoms between those patients with and those without the syndrome. Results revealed many significant differences in frequency of specific complaints between groups. However, there was much overlap between groups with regard to all complaints. A discriminant analysis of the complaint items led to a correct classification of 66 per cent of the subjects. Our findings thus indicate that the risks of misclassification of hyperventilation syndrome are relatively large when diagnosis is solely based on presenting complaints. Consequently, reported symptoms characteristic of the disorder should be used as preliminary indications requiring further evaluation.

Adolescent↗
PubMed1983

Multiple gastric lipomas.

A patient with gastric ulceration and hemorrhage due to multiple antral gastric submucosal lipomas is presented. The number and close apposition of the lipomas resulted in loss of the usual gastroscopic and radiologic findings associated with these benign tumors. Complications arising from both singly occurring and multiple gastric lipomas are discussed.

Gastrectomy↗
PubMedDate not supplied

Overreactivity of the psyche or the soma? Interindividual associations between psychosomatic symptoms, anxiety, heart rate, and end-tidal partial carbon dioxide pressure.

Current research has all but refuted previous suggestions about the role of hyperventilation as a proximal, common cause of psychosomatic symptoms. As an alternative, it has been proposed that the experience of psychosomatic symptoms is primarily associated with psychological mechanisms, i.e., with enhanced tendencies of distressed individuals to focus their attention on bodily sensations and to evaluate these in a catastrophic manner. Although this hypothesis has received considerable empirical support, physiological influences on symptom reporting have not, as yet, been fully explored. In this study, contributions of psychological and physiological factors were studied among a group of 83 normal healthy male subjects by an assessment of the interindividual relationships between symptom experience in daily life, situational and dispositional anxiety, baseline end-tidal partial carbon dioxide pressure (PCO2), and heart rate. Trait anxiety and end-tidal PCO2 each contributed separately to the prediction of the psychosomatic symptom score. Trait anxiety explained nearly one third of the symptom variance, and an additional 4% was explained by PCO2. Psychological symptoms were more strongly associated with anxiety and somatic symptoms, more strongly with PCO2. Heart rate only tended to be correlated with symptom reporting. Analysis of covariance among subgroups of extreme-symptom reporters supported the correlational findings by demonstrating that the association between hyperventilation and symptom reporting remained intact when psychological influences were factored out. The findings suggest that reports of psychosomatic symptoms represent two distinct components: one that is primarily psychological (and is unrelated to physiological factors) and a second that reflects objective variance in physiological functioning. The influence of the first component is probably greater than that of the second.

Adult↗
PubMedDate not supplied

Anxiety and vagal control of heart rate.

OBJECTIVE: Prospective studies have demonstrated that anxiety predicts sudden cardiac death, but the mechanism underlying this increased risk is unclear. This study examined whether anxiety is associated with reductions in vagal control of heart rate in healthy volunteers. METHOD: Trait anxiety (T-ANX) was measured, using the Spielberger State-Trait Anxiety Inventory (STAI), in 93 healthy men and women 25 to 44 years of age. Power spectral analysis was used to measure two indices of vagal control: baroreflex control of heart rate (BRC) and respiratory sinus arrhythmia (RSA). RESULTS: High trait anxiety (T-ANX > 41, N = 23) was associated with significantly reduced vagal control of the heart, compared with low trait anxiety (T-ANX < 31, N = 22), as indicated by a 36% reduction in BRC (p< .001) and an 8% reduction in RSA (p<.05). Furthermore, T-ANX scores were negatively correlated with levels of BRC (r = -.30, p<.005), and levels of RSA (r = -.26, p <.05). CONCLUSIONS: These findings provide evidence that trait anxiety is associated with reductions in vagal control of the heart. Additional studies are needed to examine whether low vagal control is involved in the increased risk of sudden cardiac death associated with anxiety.

Adult↗
PubMedDate not supplied

Anxiety reduces baroreflex cardiac control in older adults with major depression.

OBJECTIVE: Although depression and anxiety predict risk of cardiac mortality, the contributions of depression and anxiety to vagal cardiac control have not been systematically evaluated. The goal of this study was to examine the relationship between state anxiety and vagal control of heart rate in older adults with major depressive disorder (MDD). Older adults (50-70 years old) were selected for this study because of the greater cardiac risk associated with low vagal cardiac control across this age range. METHODS: Fifty-six men and women with MDD were evaluated. MDD was diagnosed using the Diagnostic Interview Schedule, and severity of depression was measured using the Beck Depression Inventory and the Hamilton Rating Scale for depression. State anxiety was measured using the Spielberger State Anxiety Inventory. Power spectral analysis was used to measure two indices of vagal control: baroreflex control of heart rate (BRC(SPEC)) and respiratory sinus arrhythmia (RSA). RESULTS: State anxiety was negatively correlated with levels of BRC(SPEC) (r = -0.32, p < .05), whereas depression severity was not related to either RSA or BRC(SPEC). Furthermore, BRC(SPEC) was reduced by approximately 33% in MDD patients with state anxiety scores (ST-ANX) in the highest quartile (ST-ANX > 41, N = 13), compared with patients with ST-ANX scores in the lowest quartile (ST-ANX < 25, N = 14; p < .05). CONCLUSIONS: Anxiety, but not depression severity, is associated with reduced BRC(SPEC) in older men and women. Future studies are needed to determine whether comorbid anxiety contributes to the increased cardiovascular risk associated with MDD.

Aged↗
PubMedDate not supplied

Gender differences in psychophysiological responses to speech stress among older social phobics:: congruence and incongruence between self-evaluative and cardiovascular reactions.

OBJECTIVE: Evidence suggests increased cardiovascular risk and autonomic impairment among individuals with chronic anxiety. Little attention, however, has been paid to the anxiety disorder of social phobia despite its high prevalence. Additionally, gender- and age-related cardiovascular profiles have not been examined in relation to social phobia. This study investigated cardiovascular responses to a socially threatening situation among older men and women with social phobia and control subjects. METHODS: Thirty subjects with social phobia and 30 control subjects (mean age = 65 years) were assessed during baseline, paced breathing, speech preparation, and speech presentation. Electrocardiographic variables, blood pressure, respiration, and emotional state (self-reported) were monitored. Hemodynamic variables included heart rate, blood pressure, cardiac output, and systemic vascular resistance; autonomic measures were respiratory sinus arrhythmia and baroreflex sensitivity, both markers of cardiac vagal control, and 0.10-Hz systolic blood pressure variability, an index of sympathetic vasomotor tone. RESULTS: Subjects with social phobia, in contrast to nonanxious control subjects, manifested more anxiety, embarrassment, and somatic complaints in response to stress; however, physiological measures generally did not distinguish groups. Interaction effects indicated that socially phobic women were hyperresponsive to the stressor with respect to self-reported, hemodynamic, and autonomic parameters. Socially phobic men manifested no physiological differences in comparison with control subjects, but they reported more psychological and somatic complaints. CONCLUSIONS: Gender differences in subjective and physiological responses to a socially threatening situation indicate congruence between perceived social anxiety and physiological responses in older women but not men. We found no evidence of impaired cardiovascular autonomic regulation among socially phobic men despite other reports that phobically anxious men are at greater cardiovascular risk.

Aged↗