Haemodynamic Adjustments to Mental Stress in Normotensives and Subjects with Mildly Elevated Blood Pressure

Cardiac output, heart rate, stroke volume, pre-ejection period, total peripheral resistance, systolic and diastolic blood pressure, and oxygen consumption were monitored or derived in young men with mildly elevated casual blood pressures and unambiguously normotensive control subjects before, during, and after exposure to a mental arithmetic stress. Measurements were also taken while subjects underwent graded dynamic exercise. This permitted cardiac output-oxygen consumption regression equations to be calculated and, as a consequence, cardiac output during mental stress to be represented as additional cardiac output. Systolic and diastolic blood pressure were higher during all phases of the study in the mildly elevated blood pressure group. An overall groups effect during the mental stress phase of the experiment was observed for cardiac output and pre-ejection period, and the effect for stroke volume was close to significance. Significant Groups X Periods interactions were found for cardiac output and additional cardiac output, and the heart rate effect was nearly significant. Post-hoc comparisons here indicated that, in the main, group differences in these cardiac variables were more evident during the mental arithmetic stress than during the pre- and post-task baseline periods. Total peripheral resistance did not differ reliably between groups and the cardiac effects were specific to the mental stress phase of the study.     

Cardiovascular reactivity and resistance to opposing viewpoints during intragroup conflict

This study examined how the outcomes of joint decision making relate to cardiovascular reactions when group members disagree about the decision to be taken. A conflict was experimentally induced during a joint decision‐making task, while cardiovascular markers of challenge/threat motivational states were assessed following the biopsychosocial model of challenge and threat (BPSM; J. Blascovich, 2008 ). Results show that individuals were less likely to adjust their initially preferred decision alternative the more they exhibited a cardiovascular pattern indicative of threat (i.e., relatively high total peripheral resistance and low cardiac output) compared to challenge. This finding extends the BPSM by showing a link between threat and rigidity, and emphasizes the importance of psychophysiological processes for studying intragroup conflict and decision making.     

Influence of control and physical effort on cardiovascular reactivity to a video game task

This study investigated the influences of both perceived control and physical effort on cardiovascular reactivity. Undergraduates (N = 32) played a video game task interrupted by aversive noise. Perceived control of the noise was manipulated by instructions indicating the presence or absence of a contingency between performance and noise presentations. Physical effort was manipulated by controlling the physical force required to perform the task. There was a significant main effect of control on systolic blood pressure (SBP) and total peripheral resistance (TPR), with both increasing more during low than high control conditions. The results suggest that high perceived control over aversive noise in an effortful task reduces SBP and TPR reactivity relative to low perceived control. The results are consistent with the idea that control buffers the reactivity associated with task performance under aversive conditions.     

Hemodynamic response patterns: responder type differences in reactivity and recovery

We examined whether responder type groups reflecting patterns of hemodynamic reactivity might also differ in recovery responses. Cardiac output (CO), total peripheral resistance (TPR), systolic and diastolic blood pressure, heart rate, and Heather index were assessed at rest and during speech and cold pressor tasks in young adults. Participants (n = 152) were classified as myocardial, vascular, or mixed-mild responders based on CO and TPR responses to speech presentation. Vascular responders exhibited slower CO and TPR speech recovery than the myocardial and/or mixed-mild groups. Responder type differences in reactivity showed limited task-generalizability. The sustained vascular response pattern of the vascular group is consistent with that seen in hypertension. In light of associations of heightened TPR with markers of disease risk, this suggests potentially negative health implications for vascular responders.     

The cold pressor test: Vascular and myocardial response patterns and their stability

The purposes of the present study were to compare the cardiovascular response patterns evoked by three versions of the cold pressor test (either forehead stimulation or hand or foot immersion) and to determine the reproducibility of the responses over a 2-week interval. Blood pressure, heart rate, stroke volume, cardiac output, total peripheral resistance, and systolic time intervals were obtained during rest and during the cold pressor test in 42 young men. Across conditions, the pressor response was supported by peripheral resistance increases with concomitant stroke volume decreases. Although the response panerns were generally similar across sites, exceptions were apparent for heart rate. Forehead stimulation was characterized by no significant change in heart rate, whereas limb (hand or foot) immersion was associated with significant heart rate acceleration. The responses elicited by the three cold pressor test conditions were reliable and showed little evidence of attenuation over the test-retest interval.     

The acute post-exercise response of blood pressure varies with time of day

The reactivity of ambulatory blood pressure following a given change in everyday physical activities is highest in the morning. Whether the acute response of blood pressure following a controlled bout of steady-state exercise is influenced by time of day is examined in this study. After 45 min of supine rest, 12 male normotensives completed 30 min of cycling at 70% [Formula: see text] which began at either 0800 or 1600 hours. Arterial blood pressure, cardiac output, total peripheral resistance, cutaneous blood flow and temperature were determined before, and up to 90 min after, exercise. Mean +/- SE arterial pressure, averaged over the acute (20-min) period, reduced by 7 +/- 2 mmHg following exercise at 1600 hours but increased by 3 +/- 3 mmHg following exercise at 0800 hours (P = 0.03). Total peripheral resistance fell by 4.2 +/- 0.8 mmHg l(-1) min(-1) after exercise at 1600 hour, but increased slightly by 0.1 +/- 0.5 mmHg l(-1) min(-1) after morning exercise (P = 0.02). We conclude that the acutely hypotensive effects following 30 min of steady state exercise are less marked in the morning, probably because the exercise-mediated decrease in peripheral resistance is not as apparent at this time of day.     

Shifting hemodynamics of blood pressure control during prolonged mental stress

The present study examined the hemodynamics underlying blood pressure elevations for evidence of a shift in the control of blood pressure during prolonged mental stress. Mean arterial pressure (MAP), cardiac output (CO), and total peripheral resistance (TPR) were measured at rest, during a 28-min mental arithmetic stress task, and during recovery, in 30 young healthy men and women. The stress task elicited a sustained increase in MAP: CO rose during the first half of the task but returned to baseline levels during the last quarter of the task, whereas TPR increased as the task progressed. When participants' hemodynamic reactions were classified as cardiac, vascular, or neither, there were more cardiac reactors early relative to late in the task, whereas there were more vascular reactors late relative to early. Thus, the sustained pressor response was initially supported mainly by cardiac mechanisms but subsequently by predominantly vascular mechanisms.     

Central and peripheral hemodynamics during maximal leg extension exercise

Summary The purpose of this study was to examine the central and peripheral hemodynamic adaptations to maximal leg extension exercise. Seventeen men (¯X=25 years, 84 kg) performed leg extension exercise (Universal equipment) for 12 repetitions (90s) to fatigue. Each repetition consisted of a 3s lifting motion, 1s pause, and 3s lowering motion. Impedance cardiography was used to measure stroke volume (SV), cardiac output ( ), systolic time intervals, and impedance contractility indices on a beat-by-beat basis. There were significant increases in systolic, diastolic, mean arterial pressure, total peripheral resistance, and HR during exercise. The mean remained similar throughout the protocol. SV decreased even though indices of myocardial performance indicated an enhancement of contractility. The magnitude of and SV were dependent upon the phase of leg extension. SV and during the lifting portions of the exercise were smaller than the lowering portions. The differences in SV and during the concentric and eccentric phases of the exercise most likely reflect the large static forces in exercising muscle which impeded venous return and increased afterload.     

Myocardial and Peripheral Vascular Responses to Behavioral Challenges and Their Stability in Black and White Americans

The purpose of this study was to assess the short term stability of myocardial and peripheral vascular responses to behavioral challenges, and to compare the response patterns of Black and White men. Blood pressure and heart rate, as well as stroke volume, cardiac output, total peripheral resistance, and systolic time interval measures derived from the impedance cardiogram were obtained in 12 Black and 12 White men. These measures were taken prior to and during an evaluative speech stressor, a mirror star tracing task, and a forehead cold pressor test presented during two laboratory sessions scheduled two weeks apart. In general, total peripheral resistance and impedance-derived baseline measures showed acceptable reproducibility (G greater than .85). With a few exceptions, adequate reliability was also demonstrated for change (delta) scores. All tasks raised blood pressure responses above resting levels. Blacks demonstrated significantly greater increases in total peripheral resistance responses across tasks. Whites but not Blacks also revealed increases above baseline in cardiac output and contractility as estimated by the Heather Index. These findings are consistent with the view that Blacks show greater vascular responsiveness than Whites across a variety of tasks, but reveal less myocardial responsiveness.     

The Effects of Caffeine and Stress on Blood Pressure in Individuals with and without a Family History of Hypertension

The effects of two doses of caffeine (125 mg, 250 mg) were compared to a placebo dose (3 mg) in a randomized double-blind cross-over design in 36 male caffeine users, half with and half without a family history of hypertension. Systolic blood pressure, heart rate, and respiration were recorded during rest, a mental arithmetic task, and recovery periods. I inter both resting and mental stress conditions, the two doses of caffeine on the average increased systolic pressure by 6.7 mini In compared to the placebo. The effects for the 125 me and 250 mg doses did not differ significantly. The pressor effects of caffeine and mental stress combined in an additive fashion. Systolic blood pressure levels were significantly greater in individuals with a family history of hypertension across all conditions, but not specifically in response to caffeine. The results arc comparable to those previously reported in caffeine-naive subjects.     

Cardiovascular patterns associated with appetitive and defensive activation during affective picture viewing

In this study we assessed blood pressure (BP), heart rate (HR), stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) in response to 13 picture series in 37 participants in order to investigate their hemodynamic response associated with activation of the appetitive and defensive motivational systems underlying emotional experience. BP and SV, but not TPR, increased with increasing self‐rated arousal, whereas HR decelerated more in response to negative than positive and neutral pictures. These findings suggest that modulation of the cardiovascular response to pictures is primarily myocardial. The observed response pattern is consistent with a configuration of cardiac sympathetic–parasympathetic coactivation. The relationships between self‐rated arousal, BP, and SV were mainly exhibited by men, suggesting that increases in the sympathetic inotropic effect to the heart with self‐rated arousal may be larger in men than in women.     

A new model of individual differences in hemodynamic profile and blood pressure reactivity

A quantitative, theory-driven model of hemodynamics was developed, relating reactivity in blood pressure to orthogonal dimensions of "hemodynamic profile" and "compensation deficit," which were derived from the (multiplicative) interaction of cardiac output and total peripheral resistance. A Finapres 2300e was used to estimate blood pressure, cardiac output, and total peripheral resistance in 100 healthy men and women during mental arithmetic and cold pressor tasks on two occasions. Results were consistent with model predictions. As predicted, cardiac output and peripheral resistance reactions were curvilinearly related, and blood pressure reactivity was strongly related to compensation deficit (r = .76-.89). Conversely, the orthogonally defined hemodynamic profile remained independent of blood pressure reactivity (r = .11 or less). The data show that the present model overcomes several difficulties and inconsistencies in previous attempts to obtain an independent measure of hemodynamic profile. The new model could help to elucidate sources of cardiovascular pathogenesis not suggested from the study of blood pressure reactivity alone.     

Stimulus dimensions of the cold pressor test and the associated patterns of cardiovascular response

Hemodynamics of the cold pressor response in relation to its pain and nonpain stimulus components were investigated in normotensive college men using the foot and forehead cold pressor tasks. Mechanisms of pain- and non-pain-related increases in blood pressure were analyzed as residual effects of concurrent changes in total peripheral resistance and cardiac output. The identified partial relationships suggested that the response pattern associated with pain included positive change both in cardiac output and in total peripheral resistance, whereas the nonpain-related response was limited to an increase in total peripheral resistance. Analyses of individual differences in car-diovascular responses to pain further indicated that pain-related increments in blood pressure were mediated by a steeper rise in total peripheral resistance, an increase in heart rate, and an apparent increase in preload. At baseline, high reactors to pain manifested relatively elevated total perpheral resistance, diminished cardiac output, and an indication of a reduced inotropic state, suggesting that altered basal homeostasis may discriminate normotensive individuals displaying heightened cardiovascular reactivity to aversive cold stimulation.     

Continuous monitoring of haemodynamic parameters in humans during the early phase of simulated diving with and without breathholding

This study examined the integrative changes of blood pressure (BP) and stroke volume (SV) leading to the initial biphasic heart rate (f _c) response (first 15 s) in simulated diving manoeuvres with and without breathholding (BH). Simulated diving was studied in ten young healthy volunteers by application of a gel-filled pack at 0°C and 18°C on the forehead with and without BH. Beat-by-beat and second-to-second f _c, BP, SV, and total peripheral vascular resistance (TPR) were followed by continuous non-invasive monitoring. In all conditions (BH with forehead cooling at 0° and 18°C) there was an early rise in BP triggering the first tachycardial response (f _c acceleration) which was immediately counteracted by the concurrent further increase of SV leading to the second phase of early bradycardic response (f _c deceleration). Furthermore, the continuous beat-by-beat and second-to-second monitoring allowed the documentation of a highly significant increase of TPR within the first few seconds of the manoeuvres. Our data further indicated that the differences in haemodynamics observed during the stimuli at different temperatures was overruled by BH. Detailed comparisons of the beat-by-beat and second-to-second analyses were unable to show that one method was better than the other. Using continuous non-invasive monitoring of haemodynamic variables during simulated diving manoeuvres it was possible to provide better insights into the physiological principles and meaning of the diving reflex in humans. Accepted: 2 September 1999     

Heart Rate and Oxygen Consumption during Mental Arithmetic,a Video Game,and Graded Exercise: Further Evidence of Metabolically-Exaggerated Cardiac Adjustments?

Heart rate, plus various metabolic and ventilatory indices, were monitored while 20 young male subjects were exposed to a video game and a stressful mental arithmetic task. Measurements were also made while subjects undertook graded isotonic exercise. All measures changed as a function of psychological challenge, and during exercise physiological activity increased as an orderly function of workload. For each subject, heart rate was plotted against oxygen consumption over the various exercise loads. For the majority of subjects the analogous data points for the video game and mental arithmetic lay reliably above the exercise heart rate-oxygen consumption regression lines. When these regression lines were used to predict heart rate values during psychological challenge, the predicted values were significantly less than the values actually recorded for both tasks; although the discrepancy between predicted and actual values was on average greater with mental arithmetic, the difference was not statistically reliable. Pre-stressor baseline conditions were also associated with heart rate levels greater than predicted, albeit to a lesser extent. Finally, while both stressors produced heart rate adjustments additional to expectancies, inter-task consistency was low.     

Cardiovascular reactivity, Type A behavior, and coronary heart disease: Comparisons between myocardial infarction patients and controls during laboratory-induced stress

Cardiovascular responses to a series of laboratory stressors were examined in middle-aged Type A and Type B men. The subjects were 30 patients with diagnosed myocardial infarction (NYHA Class 1) and 26 age-matched healthy controls. All subjects were nonsmokers in the normotensive range, and none were on medication. Blood pressure, heart rate, forearm blood flow and resistance, and impedance cardiography-determined response variables were obtained during performance and recovery periods of both mental and physical tasks. The patients showed elevated reactivity in systolic blood pressure and cardiac output and prolonged systolic lime ratio during mental stress tasks and elevated total peripheral resistance and lower cardiac output and stroke volume during physical tasks, as compared with control subjects. Thus, the difference in blood pressure reactivity between patients and controls appeared to be primarily dependent on the vascular component during physical tasks, whereas the mental tasks promoted a hemodynamic response pattern more consistent with beta adrenergic activation. Type A men, irrespective of coronary status, showed larger systolic and diastolic blood pressure response to both mental and physical stress than did Type B men.     

Cardiac papillary fibroelastoma: Retrospective clinicopathologic study of 17 tumors with resection at a single institution and literature review

Cardiac papillary fibroelastomas (PFEs), which are mainly found in the valves, are rare benign tumors that can cause embolism. Single-center surgical experience in the treatment of this tumor is uncommon.     

Antibiotic resistance associated with the COVID-19 pandemic: a systematic review and meta-analysis

BackgroundCOVID-19 and antimicrobial resistance (AMR) are two intersecting global public health crises.ObjectiveWe aimed to describe the impact of the COVID-19 pandemic on AMR across health care settings.Data sourceA search was conducted in December 2021 in WHO COVID-19 Research Database with forward citation searching up to June 2022.Study eligibilityStudies evaluating the impact of COVID-19 on AMR in any population were included and influencing factors were extracted. Reporting of enhanced infection prevention and control and/or antimicrobial stewardship programs was noted.MethodsPooling was done separately for Gram-negative and Gram-positive organisms. Random-effects meta-analysis was performed.ResultsOf 6036 studies screened, 28 were included and 23 provided sufficient data for meta-analysis. The majority of studies focused on hospital settings (n = 25, 89%). The COVID-19 pandemic was not associated with a change in the incidence density (incidence rate ratio 0.99, 95% CI: 0.67–1.47) or proportion (risk ratio 0.91, 95% CI: 0.55–1.49) of methicillin-resistant Staphylococcus aureus or vancomycin-resistant enterococci cases. A non-statistically significant increase was noted for resistant Gram-negative organisms (i.e. extended-spectrum beta-lactamase, carbapenem-resistant Enterobacterales, carbapenem or multi-drug resistant or carbapenem-resistant Pseudomonas aeruginosa or Acinetobacter baumannii, incidence rate ratio 1.64, 95% CI: 0.92–2.92; risk ratio 1.08, 95% CI: 0.91–1.29). The absence of reported enhanced infection prevention and control and/or antimicrobial stewardship programs initiatives was associated with an increase in gram-negative AMR (risk ratio 1.11, 95% CI: 1.03–1.20). However, a test for subgroup differences showed no statistically significant difference between the presence and absence of these initiatives (p 0.40).ConclusionThe COVID-19 pandemic may have hastened the emergence and transmission of AMR, particularly for Gram-negative organisms in hospital settings. But there is considerable heterogeneity in both the AMR metrics used and the rate of resistance reported across studies. These findings reinforce the need for strengthened infection prevention, antimicrobial stewardship, and AMR surveillance in the context of the COVID-19 pandemic.     

Primary cardiac sarcomas: a clinicopathologic analysis of a series with follow-up information in 17 patients and emphasis on long-term survival

Although cardiac sarcomas are rare in comparison to their soft tissue counterparts, they are the second most common type of primary cardiac neoplasm. Of the few hundred cases reported, most has been based on autopsy series. A series of 27 cardiac sarcomas removed at surgery for curative and diagnostic intent were reviewed for clinicopathologic features with correlation to available postoperative follow-up data in 17 patients. There were 6 angiosarcomas, 6 myxofibrosarcomas, 3 malignant peripheral nerve sheath tumors, 3 leiomyosarcomas, 2 synovial sarcomas, 1 epithelioid hemangioendothelioma, 1 chondrosarcoma, 1 osteosarcoma, and 4 poorly differentiated sarcomas. There was a wide age and size range with slight female predilection. There were 20 cases that arose in the atria/pulmonary vessels, 4 in the ventricles, 1 in mitral valve, and 2 in epi/pericardium. There was a slight left predilection. The histologic grade was low in 4, moderate in 3, and high in 20 cases. Six high-grade and 1 low-grade tumors were also treated with adjuvant chemotherapy and/or radiation. In 17 patients with follow-up data, 6 of 12 patients with high-grade tumor died (4 within 5 days of the initial surgery, 1 in 21 months, and 1 in 131 months), and 1 patient with moderate-grade tumor and all 4 patients with low-grade tumor were alive without evidence of disease at the end of follow-up. Tumor grade appeared to be prognostically important in cardiac sarcoma. Long survival was achieved in patients who survived the initial surgery well.