Changes In Interbeat Interval Research Articles

Feelings in words: Emotion word use and cardiovascular reactivity in marital interactions.

Putting feelings into words is often thought to be beneficial. Few studies, however, have examined associations between natural emotion word use and cardiovascular reactivity. This laboratory-based study examined emotion word use (i.e., from computerized text analysis) and cardiovascular reactivity (i.e., interbeat interval changes from baseline) across two interaction contexts (i.e., conflict and positive conversations) in 49 mixed-sex married couples (age: M = 43.11, SD = 9.20) from diverse socioeconomic backgrounds. We focused on both frequency (i.e., relative proportion of emotion words) and diversity (i.e., relative proportion of unique emotion words) of emotion words. Data were collected between 2015 and 2017 and analyzed treating both partners and conversations as repeated measures, resulting in 196 observations overall (four per dyad). Findings showed that (a) when spouses used more negative emotion words (especially anger), they showed higher cardiovascular reactivity. This finding was robust when controlling for covariates; generalized across gender, interaction contexts, and socioeconomic status. Moreover, (b) when spouses used a more diverse negative emotion vocabulary, they showed higher cardiovascular reactivity, but this was not robust when controlling for negative emotion word frequency. Associations between (c) positive emotion word use and cardiovascular reactivity were not statistically significant. Verbalizing negative emotions thus seems to go along with higher cardiovascular reactivity, at least in the short term. Replication is needed across other relationship types, genders, and sexual orientations. These findings highlight emotion word use as an indicator of cardiovascular reactivity, which has implications for the identification of potential health risks that emerge during marital interactions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Dynamic Phase Extraction: Applications in Pulse Rate Variability.

Pulse rate variability is a physiological parameter that has been extensively studied and correlated with many physical ailments. However, the phase relationship between inter-beat interval, IBI, and breathing has very rarely been studied. Develop a technique by which the phase relationship between IBI and breathing can be accurately and efficiently extracted from photoplethysmography (PPG) data. A program based on Lock-in Amplifier technology was written in Python to implement a novel technique, Dynamic Phase Extraction. It was tested using a breath pacer and a PPG sensor on 6 subjects who followed a breath pacer at varied breathing rates. The data were then analyzed using both traditional methods and the novel technique (Dynamic Phase Extraction) utilizing a breath pacer. Pulse data was extracted using a PPG sensor. Dynamic Phase Extraction (DPE) gave the magnitudes of the variation in IBI associated with breathing [Formula: see text] measured with photoplethysmography during paced breathing (with premature ventricular contractions, abnormal arrhythmias, and other artifacts edited out). [Formula: see text] correlated well with two standard measures of pulse rate variability: the Standard Deviation of the inter-beat interval (SDNN) (ρ = 0.911) and with the integrated value of the Power Spectral Density between 0.04 and 0.15Hz (Low Frequency Power or LF Power) (ρ = 0.885). These correlations were comparable to the correlation between the SDNN and the LF Power (ρ = 0.877). In addition to the magnitude [Formula: see text], Dynamic Phase Extraction also gave the phase between the breath pacer and the changes in the inter-beat interval (IBI) due to respiratory sinus arrythmia (RSA), and correlated well with the phase extracted using a Fourier transform (ρ = 0.857). Dynamic Phase Extraction can extract both the phase between the breath pacer and the changes in IBI due to the respiratory sinus arrhythmia component of pulse rate variability ([Formula: see text], but is limited by needing a breath pacer.

Heart Rate and Breathing Are Not Always in Phase During Resonance Frequency Breathing.

For many years it has been an axiom among practitioners of heart rate variability biofeedback that heart rate and breathing vary in phase with each other when people do resonance frequency breathing. When people breathe at the frequency of the baroreflex system, about 0.1Hz, heart rate and blood pressure have been found to oscillate 180° out of phase, while heart rate and breathing are in phase (zero-degree phase). Thus breathing stimulates the baroreflex by augmenting the baroreflex response with each breath, an effect that is magnified by resonance properties in the baroreflex system. The original data on these relationships came from a study of highly athletic healthy young people. To test this relationship we analyzed phase relationship data between cardiac interbeat interval and breathing during 5-min periods of resonance frequency breathing among 24 adults from a recent study of heart rate variability biofeedback to treat adults with mild to moderate currently symptomatic asthma, ages between 18 and 70. For the specific frequency near 0.1Hz with the highest amplitude of HRV we calculated coherence and phase between cardiac interbeat interval (IBI) and the respiration curve using the WinCPRS program. Among records with coherence > 0.8, we found a phase relationship of 109° rather than the expected 180°, with IBI changes leading breathing. We computed Spearman correlation coefficients between phase and various subject characteristics, including age, gender, height, and asthma severity. We found no relationship between phase and gender, height, or asthma physiology or symptoms. However, when controlled for gender and height, we found a moderate size significant correlation between phase and age, with younger participants having values closer to 180°, r = 0.47, p < 0.03. It is possible that cardiovascular characteristics of older people affect the phase relationship. Despite the deviation from the in-phase relationship among older individuals, breathing nevertheless stimulated the baroreflex and produced high-amplitude heart rate oscillations. Implications are discussed for HRV biofeedback training protocols. Replication in a healthy population is needed in order to determine the universality of these findings.

Multi-lag HRV analysis discriminates disease progression of post-infarct people with no diabetes versus diabetes.

Diabetes mellitus is associated with multi-organ system dysfunction including the cardiovascular and autonomic nervous system. Although it is well documented that post-infarct patients are at higher risk of sudden cardiac death, diabetes adds an additional risk associated with autonomic neuropathy. However it is not known how the presence of diabetes in post-infarct patients affects cardiac rhythm. The majority of HRV algorithms for determining cardiac inter-beat interval changes describe only beat-to-beat variation determined over the whole heart rate recording and therefore do not consider the ability of a heart beat to influence a train of succeeding beats nor whether or how the temporal dynamics of the inter-beat intervals changes. This study used Poincaré Plot derived features and incorporated increased lag intervals to compare post-infarct patients with no history of prior infarct with or without diabetes and found that for the nondiabetic post-infarct patients only increased lag of short term correlation (SD1) predicted mortality, whereas in the diabetic post-infarct group only long-term correlations (SD2) significantly predicted mortality at a follow-up period of eight years. Temporal dynamics measured as a complex correlation measure (CCM) was also a significant predictor of mortality only in the diabetic post-infarct cohort. This study highlights the different pathophysiological progression and risk profile associated with presence of diabetes in a post-infarct patient population at eight year follow-up.

Applying imagined contact to improve physiological responses in anticipation of intergroup interactions and the perceived quality of these interactions

AbstractThis experiment (N = 49) is the first to show that imagined contact can buffer anticipatory physiological responses to future interactions, and improve the quality of these interactions. Participants imagined a positive interaction with a person with schizophrenia, or in a control condition, a person who did not have schizophrenia.They then interacted with a confederate whom they believed had schizophrenia. Participants in the imagined contact condition reported more positive attitudes and less avoidance of people with schizophrenia, displayed smaller anticipatory physiological responses, specifically smaller changes in interbeat interval and skin conductance responses, and had a more positive interaction according to the confederate. These findings support applying imagined contact to improve interactions with people with severe mental illnesses.

Depression is associated with increased vagal withdrawal during unpleasant emotional imagery after cardiac surgery.

The aim of this study was to examine the influence of depression on heart rate and heart rate variability (HRV) during emotional imagery in patients after cardiac surgery. Based on the scores of the Center for Epidemiological Studies of Depression (CES-D) scale, 28 patients after cardiac surgery were assigned either to the group with depression (CES-D scores ≥ 16; N = 14) or the one without depression (CES-D scores<16; N = 14). Each patient completed a rest period and an emotional imagery including pleasant, neutral and unpleasant scripts. Inter-beat intervals (IBIs) and HRV were measured during the entire protocol. Compared to nondepressed patients, those with depression had greater reductions in high frequency expressed in normalized units (HF n.u.) during the imaging of the unpleasant script (p = .003, Cohen's d = 1.34). Moreover, HF n.u. were lower during the imaging of the unpleasant script than the pleasant one in depressed patients only (p = .020, Cohen's d = 0.55). CES-D scores were also inversely correlated with residualized changes in IBIs (r = -.38, p = .045) and HF n.u. (r = -.49, p = .008) from rest to the imaging of the unpleasant script. The relationship between depression and increased vagal withdrawal during unpleasant emotional imagery extends to patients after cardiac surgery. The present study suggests that increased vagal withdrawal to negative emotions in patients after cardiac surgery may mediate the conferral of cardiac risk by depression.

Using extended contact to improve physiological responses and behavior toward people with schizophrenia

Extended contact has been shown to improve explicit and implicit attitudes toward a number of outgroups, but not yet toward people with mental health conditions. Using people with schizophrenia as the target group, this experiment is the first to demonstrate that extended contact can reduce explicit prejudice, buffer stress responses to future interactions, improve non-verbal behavior, and improve the quality of interactions in a manner detectable by the target group member. Participants watched a video of a brief, positive interaction between two strangers, one of whom they were led to believe had schizophrenia. Control participants watched the same video without being told that the person had schizophrenia. They then participated in a social interaction with a confederate whom they were led to believe had the disorder. Participants' cardiovascular and electrodermal activity were monitored immediately before the interaction. The interaction was also secretly recorded to allow independent judges to assess the participants' non-verbal behaviors. The confederate also rated the positivity of each interaction. Participants in the extended contact condition reported more positive attitudes toward people with schizophrenia, displayed more positive non-verbal behaviors, and had a more positive interaction with the confederate. Moreover, just prior to the interaction, participants in the extended contact condition displayed smaller anticipatory stress responses, as reflected in smaller changes in interbeat interval and non-specific skin conductance responses during this phase. Together, these findings support the use of the extended contact as an intervention that could lead to genuine changes in attitudes toward and treatment of people with severe mental health disorders.

Effects of muscarinic receptor stimulation on Ca2+ transient, cAMP production and pacemaker frequency of rabbit sinoatrial node cells

We investigated the contribution of the intracellular calcium (Cai2+) transient to acetylcholine (ACh)-mediated reduction of pacemaker frequency and cAMP content in rabbit sinoatrial nodal (SAN) cells. Action potentials (whole cell perforated patch clamp) and Cai2+ transients (Indo-1 fluorescence) were recorded from single isolated rabbit SAN cells, whereas intracellular cAMP content was measured in SAN cell suspensions using a cAMP assay (LANCE®). Our data show that the Cai2+ transient, like the hyperpolarization-activated “funny current” (I f) and the ACh-sensitive potassium current (I K,ACh), is an important determinant of ACh-mediated pacemaker slowing. When I f and I K,ACh were both inhibited, by cesium (2 mM) and tertiapin (100 nM), respectively, 1 μM ACh was still able to reduce pacemaker frequency by 72%. In these I f and I K,ACh-inhibited SAN cells, good correlations were found between the ACh-mediated change in interbeat interval and the ACh-mediated change in Cai2+ transient decay (r 2 = 0.98) and slow diastolic Cai2+ rise (r 2 = 0.73). Inhibition of the Cai2+ transient by ryanodine (3 μM) or BAPTA-AM (5 μM) facilitated ACh-mediated pacemaker slowing. Furthermore, ACh depressed the Cai2+ transient and reduced the sarcoplasmic reticulum (SR) Ca2+ content, all in a concentration-dependent fashion. At 1 μM ACh, the spontaneous activity and Cai2+ transient were abolished, but completely recovered when cAMP production was stimulated by forskolin (10 μM) and I K,ACh was inhibited by tertiapin (100 nM). Also, inhibition of the Cai2+ transient by ryanodine (3 μM) or BAPTA-AM (25 μM) exaggerated the ACh-mediated inhibition of cAMP content, indicating that Cai2+ affects cAMP production in SAN cells. In conclusion, muscarinic receptor stimulation inhibits the Cai2+ transient via a cAMP-dependent signaling pathway. Inhibition of the Cai2+ transient contributes to pacemaker slowing and inhibits Cai2+-stimulated cAMP production. Thus, we provide functional evidence for the contribution of the Cai2+ transient to ACh-induced inhibition of pacemaker activity and cAMP content in rabbit SAN cells.

Assessing baroreflex sensitivity by the transfer function method: what are we really measuring?

by governing the autonomic outflow to the heart and blood vessels, arterial baroreceptors play a central role in controlling short-term blood pressure responses to the hemodynamic perturbations continuously occurring in daily life. Abnormalities in baroreflex function are thought to play an

Effects of variation in posture and respiration on RSA and pre‐ejection period

The extent to which variation in posture and respiration can confound pre-ejection period and respiratory sinus arrhythmia (RSA) as indices of cardiac sympatho-vagal activity was examined. Within-subjects changes in these measures were assessed in 36 subjects during different postures and (paced) respiratory frequencies. Changes from supine to sitting to standing led to reduced RSA values and longer pre-ejection periods, reflecting the known decrease in vagal but not the increase of sympathetic activity. Multilevel path analysis showed that within-subjects changes in sympatho-vagal balance were faithfully reflected by changes in interbeat interval, but imperfectly by changes in RSA and pre-ejection period. It was concluded that pre-ejection period should be stratified for posture and RSA for respiratory frequency to reliably index changes in sympatho-vagal balance when these factors are prone to change (e.g., during 24-h ambulatory recording).

Respiratory sinus arrhythmia as an index of emotional response in young adults.

The relationship between respiratory sinus arrhythmia (RSA) and valence and arousal remains unclear. In the present study, the associations between emotion responses and tonic or task-related changes in RSA were assessed. Specifically, the sensitivities of changes in interbeat interval, RSA, and skin conductance to the valence and arousal values of emotional stimuli were examined. This study also explored the association between tonic RSA and subjective, expressive, and physiological emotional responses. Response measures were collected from 56 adults during baseline and film-viewing periods. Tonic RSA was not significantly related to any of the response measures. Increased skin conductance and decreased RSA were associated with arousal independent of valence. Interbeat interval was related to affective valence and not arousal. These findings suggest that RSA may be a useful adjunct to skin conductance measures in assessing emotional arousal.

Influence of preparatory schema on the speed of responses to spatially compatible and incompatible stimuli

We investigated the inhibitory regulation of perceptual–motor processing streams in a task that switched between spatially compatible and incompatible stimulus–response mappings. Thirty male and female college‐aged participants performed a reaction time (RT) task in which the response was either spatially compatible or not depending on a cue immediately preceding the stimulus. The cue‐to‐stimulus interval (CI) was either 50 or 500 ms. Incompatible mapping yielded the typical slower responses than compatible mapping at 500 ms, but not at 50 ms. Changes in cardiac interbeat interval (IBI) and performance suggested that automatic responses to compatible stimuli were suppressed at 50 ms. Both performance and IBI changes as well as individual differences in these measures suggested a precue preparatory schema or set biased toward suppressing the compatible mapping. An alternate hypothesis of a cue‐induced suppression was questioned. The results illustrate the operation of different supervisory processes in the anticipatory and online control of action.

The relationship of respiratory sinus arrhythmia to the co‐activation of autonomic and facial responses during the Rorschach test

We studied the relationship of respiratory sinus arrhythmia (RSA) to the co-activation of autonomic and facial expressive responses in 37 adult men during Rorschach testing. Interbeat interval (IBI), electrodermal activity, and facial electromyography were recorded continuously during the experiment. Prevailing mood and variability in the experience of valence and arousal were also measured. Bivariate intraindividual time series analysis was used to quantify spontaneously coupled phasic physiological responses. The results suggested that (a) spontaneous autonomic and expressive responses tend to parallel in time; (b) baseline, task-level, and task-induced change of RSA were positively related to coupled autonomic-expressive responses, a change in mood toward a more energetic state, and a tendency to have more variability in the emotional experience during the task; and (c) especially cardiac-expressive response coupling was related to mood change. It is concluded that the vagal system is related to the control of facial muscle activity and may mediate both tonic and phasic emotion-related changes in IBI. The role of phasic intraindividual response patterns in emotional and social behavior is highlighted.

The relationship of respiratory sinus arrhythmia to the co-activation of autonomic and facial responses during the Rorschach test

We studied the relationship of respiratory sinus arrhythmia (RSA) to the co-activation of autonomic and facial expressive responses in 37 adult men during Rorschach testing. Interbeat interval (IBI), electrodermal activity, and facial electromyography were recorded continuously during the experiment. Prevailing mood and variability in the experience of valence and arousal were also measured. Bivariate intraindividual time series analysis was used to quantify spontaneously coupled phasic physiological responses. The results suggested that (a) spontaneous autonomic and expressive responses tend to parallel in time; (b) baseline, task-level, and task-induced change of RSA were positively related to coupled autonomic–expressive responses, a change in mood toward a more energetic state, and a tendency to have more variability in the emotional experience during the task; and (c) especially cardiac–expressive response coupling was related to mood change. It is concluded that the vagal system is related to the control of facial muscle activity and may mediate both tonic and phasic emotion-related changes in IBI. The role of phasic intraindividual response patterns in emotional and social behavior is highlighted.

Maturational changes in heart rate and heart rate variability in low birth weight infants.

To provide insight into the maturation of neural mechanisms responsible for variability in heart rate during quiet and active sleep, 6-hour continuous electrocardiographic recordings and simultaneous minute-by-minute behavioral activity state assignments were performed in 61 healthy, growing low birth weight infants. The infants weighed 795-1600 g at birth and ranged between 31-38 weeks in postconceptional age. During this age interval there was a decrease in heart rate during quiet sleep and an increase in both time domain and frequency domain measures of the variability in cardiac interbeat intervals. In quiet sleep, global variability, measured as SD of R-R intervals, increased in relation to age, as did higher frequency variability, measured as the square root of the mean of squared successive differences in R-R intervals. Developmental changes in the 0.5-2.0 Hz spectral power band of RR-interval variability, another measure of high frequency variability, paralleled the changes seen in the time domain measure. Evaluation of patterns of changes in the magnitude and direction of successive interbeat intervals provided evidence that the incidence of sustained accelerations or decelerations increased whereas the incidence of no change in consecutive RR-intervals decreased as infants matured. Among the various measures of heart rate variability, the incidence of sustained change and no change in successive interbeat intervals were most closely related to postconceptional age in both sleep states. The overall decrease in heart rate, increase in heart rate variability, and increase in the pattern of changes in interbeat interval with postconceptional age are consistent with the maturation of the autonomic cardio-regulatory activity from 31-38 weeks age.

Graphical and statistical techniques for cardiac cycle time (phase) dependent changes in interbeat interval: Problems with the Jennings et al. (1991) proposals

Two apparently new effects in human cardiac responding, “primary bradycardia” and “vagal inhibition”, were first described by the Laceys. These effects have been considered by some researchers to reflect differential cardiac innervation, analogous to similar effects observed in animal preparations with direct vagal stimulation. However, it has been argued that such effects arise merely from the data-analytic techniques introduced by the Laceys, and hence are not genuine cardiac cycle effects. Jennings, van der Molen, Somsen and Ridderinkhoff ( Psychophysiology, 28 (1991) 596–606) recently proposed a plotting technique and statistical procedure in an attempt to resolve this issue. The present paper demonstrates that the plotting technique fails to achieve their stated aim, since it identifies data from identical cardiac responses as showing cardiac-cycle effects. In addition, the statistical procedure is shown to be reducible to a trivial test of response occurrence. The implication of these demonstrations, in the context of other work, is that this area of investigation has reached a dead end.

Dynamic analysis of cardiac R-R intervals in normal infants and in infants who subsequently succumbed to the sudden infant death syndrome.

Infants who subsequently succumb to the sudden infant death syndrome (SIDS) have higher heart rates and reduced heart rate variation compared with other infants. We examined dynamic changes in cardiac interbeat intervals to explore these differences in cardiac control. Recordings of electrocardiographic activity and respiratory movement were acquired from 13 SIDS victims before their deaths. Moment-to-moment changes in R-R intervals during quiet sleep, rapid eye movement sleep, and waking were compared with values of 13 matched control infants. For each sleep-waking state, every R-R interval was plotted against the previous interval (Poincaré plots), and each change in interbeat interval was plotted against the previous change. Dispersion of interbeat intervals at different heart rates was reduced in SIDS victims, resulting in Poincaré plots markedly different from those of controls. The dispersion, sampled at the 10th and 90th percentiles of heart rates, was reduced across all sleep-waking states in SIDS victims. At high heart rates, the difference between groups disappeared after correcting for basal rate; however, the reduced range at low heart rates was independent of basal rate. SIDS victims also showed smaller beat-to-beat changes in heart rate and fewer sustained runs of consistent heart rate changes during waking relative to controls. The differences in cardiac rate dynamics suggest altered autonomic control in infants who succumb to SIDS. We speculate that the autonomic disturbance may lead to cardiac instability or may indicate CNS alterations with the potential to affect other vital functions.

Anger expression, hostility, anxiety, and patterns of cardiac reactivity to stress.

The majority of studies investigating the relationships between psychological characteristics and cardiovascular reactivity to stress use a research strategy in which discrete traits are evaluated in isolation. The present study examined the effects of additive and/or interactive relationships among traits on cardiac reactivity to a mental arithmetic task. In addition, impedance cardiographic techniques were employed to examine potential relationships between such psychological traits and a specific measure--pre-ejection period (PEP)--of sympathic influence on the heart. Forty-nine undergraduate men performed a mental arithmetic task while continuous measures of PEP and interbeat interval (IBI) were collected. The subjects then completed questionnaires measuring anger expression, hostility, and trait anxiety. Analyses of variance (ANOVAs) showed a significant main effect for anger-out on PEP change from baseline, but not for IBI. Results also showed that anger-in interacted with anger-out and hostility to affect both PEP and IBI changes significantly. Other results indicated that subjects in the high anger-in/low anger-out and high anger-in/low hostility groups did not show significant PEP change, although they nevertheless showed significant IBI change. These results highlight the importance of the consideration of interactions among traits in predicting cardiac reactivity and of the importance of measuring specific indexes of sympathetic arousal.

Graphical and Statistical Techniques for Cardiac Cycle Time (Phase) Dependent Changes in Interbeat Interval

Cardiac cycle time effects refer to the relative lengthening or shortening of a single cardiac cycle as a function of when in the cycle brief sensorimotor events occur. These effects may provide short-latency measures of cardiac sensitivity to psychological events. Conventional representations have, however, failed to clearly separate changes in interbeat interval due to cycle time--i.e., phase dependent changes--from other types of change. This paper advocates a particular technique of plotting to solve these representation problems. Heartbeat timing is represented in real time and in the context of beats both preceding and following the event of interest. The plot, a phase-sensitive plot, conceptualizes phase-sensitive (cardiac cycle time) effects as a change in linear or higher order trend. Thus, an adaptation of trend analysis is proposed as an efficient statistical analysis that follows directly from the proposed representational technique.

Human Pavlovian HR-decelerative conditioning with negative tilt as US: evidence of vagal and sympathetic influences on the UR in dogs

Following a review of studies employing negative tilt in human Pavlovian conditioning of heart rate (HR) deceleration (Furedy et al., in press), this paper reports data based on animal subjects on such physiological aspects of the decelerative unconditioned response (UR) as the degree of vagal involvement. Five anesthetized dogs underwent 90° negative body tilts pre- and postbilateral vagotomy, while interbeat interval (IBI), left ventricular pressure (LVP) and its first derivative, d(LVP)/dt, which is a measure of sympathetic cardiac drive, were recorded. Consistent with the vagal interpretation of the tilt-induced decelerative UR, the results indicated that vagotomy markedly changed the tilt-induced bradycardic reflex from a fast-recruiting, large-magnitude (over 45%), and sustained (throughout the 20–27-s tilt) IBI increase, to slower-recruiting, and markedly smaller (less than 5%) IBI increase. However, there was also evidence of an initial sympathetic excitation of about 5 s, as indicated by a 45% increase in d(LVP)/dt, which returned to baseline level by 9 s following tilt onset. Vagotomy increased this tilt-induced sympathetic excitation to about 100%, and it remained at above 70% throughout the tilt. Prevagotomy LVP showed a slight (about 10%) and delayed (about 6 s following tilt onset) depressor response, which was eliminated by vagotomy. Finally, unaveraged data from individual dogs suggested that prevagotomy, LVP changes preceded IBI changes. Regarding implications of these results for human HR deceleration-inducing preparations, we conclude that the different physiological mechanisms that accompany and/or produce a given change in HR need continuing investigation with multiple dependent physiological variables (which are assessed for topographical differences), and in both human and animal preparations.