Acute risk factors for myocardial infarction

Short-term vascular responses to spring and fall daylight savings time shifts

Daylight saving time (DST) is a Western biannual time transition, setting the clock back 1 h in the fall and forward 1 h in the spring. There is an epidemiological link between DST and acute myocardial infarction risk in the first week following the spring shift; however, the mechanisms underlying the effect of DST on cardiovascular function remain unclear. The purpose of this study was to explore the short-term cardiovascular changes induced by fall and spring shifts in DST in a convenience sample of healthy adults. We hypothesized that spring, but not fall, DST shifts would acutely increase central pulse wave velocity, the gold standard measurement of central arterial stiffness. Twenty-one individuals (fall: n = 10; spring: n = 11) participated in four visits, occurring 1 wk before and at +1, +3, and +5 days after spring and fall time transitions. Central, brachial, and radial pulse wave velocity as well as carotid augmentation index were assessed with applanation tonometry. Sleep quality and memory function were assessed via questionnaire and the Mnemonic Similarities Task, respectively. Neither fall or spring transition resulted in changes to cardiovascular variables (carotid-femoral pulse wave velocity, carotid-brachial pulse wave velocity, carotid-radial pulse wave velocity, heart rate, mean arterial pressure, or augmentation index), sleep quality, or cognitive function (all P > 0.05). Our findings do not provide evidence that DST shifts influence cardiovascular outcomes in healthy adults. This study emphasizes the need for further research to determine the mechanisms of increased cardiovascular disease risk with DST that help explain epidemiological trends.NEW & NOTEWORTHY The debate of whether to abolish daylight savings time (DST) is, in part, motivated by the population-level increase in all-cause mortality and incidence of cardiovascular events following DST; however, there is an absence of data to support a physiological basis for risk. We found no changes in pulse wave velocity or augmentation index during the subacute window of DST. Large multisite trials are necessary to address the small, but meaningful, effects brought on by a societal event.

Cannabis and Pain Control After Total Hip and Knee Arthroplasty

Cannabis use among the elderly has increased over the previous 2 decades. This has translated to a greater proportion of orthopedic procedures being undertaken on these patients. This review provides clinicians with evidence-based information on the effects of cannabis on pain control in THA and TKA, to help counsel these patients and facilitate their perioperative management. The review specifically focuses on the following: origins of cannabis; biochemistry of cannabis; medical versus recreational cannabis; pharmacology of cannabis; effects of cannabis on bone metabolism; preoperative pain control; preoperative systemic considerations; intraoperative considerations; postoperative pain control, postoperative systemic considerations; and scope for future work.

A 28-year-old male with spontaneous coronary artery dissection complicated by apical thrombus and acute ischemic stroke: An interesting case

Spontaneous coronary artery dissection is described as the intramural bleeding that separates the layers of an epicardial coronary artery wall, either with or without an intimal tear. Atherosclerosis, iatrogenic damage, or trauma are not linked to this syndrome. Here we present a 28-year-old male with 1 month history stroke but no any chronic disease as well family history of heart disease who presented with 2 days' duration of typical cardiac chest pain. Based on an emergency electrocardiogram that showed biphasic T-wave inversion with ST-elevation myocardial infarction, the patient was taken to the a  catheterization laboratory(cath-lab), with the result of spontaneous coronary artery dissection of the left anterior dissenting artery with thrombolysis in myocardial infarction flow grade 0 and normal of other vessels. Then we successfully did angioplasty, and the patient was discharged with aspirin 100 mg 1 × 1, clopidogrel 75 mg 1 × 1, and rivaroxaban 20 mg 1 × 1.

Influence of Intermittent Fasting During Ramadan on Circadian Variation of Symptom-Onset and Prehospital Time Delay in Acute ST-Segment Elevation Myocardial Infarction

Ramadan interferes with circadian rhythms mainly by disturbing the routine patterns of feeding and smoking. The objective of this study was to investigate the circadian pattern of ST elevation acute myocardial infarction (STEMI) during the month of Ramadan. We studied consecutive STEMI patients 1 month before and after Ramadan (non-Ramadan group-NRG) and during Ramadan (Ramadan group-RG). The RG group was also divided into two groups, based on whether they chose to fast: fasting (FG) and non-fasting group (NFG). The time of STEMI onset was compared. A total of 742 consecutive STEMI patients were classified into 4 groups by 6 h intervals according to time-of-day at symptom onset. No consistent circadian variation in the onset of STEMI was observed both between the RG (P = .938) and NRG (P = .766) or between the FG (P = .232) and NFG (P = .523). When analyzed for subgroups of the study sample, neither smoking nor diabetes showed circadian rhythm. There was a trend towards a delay from symptom onset to hospital presentation, particularly at evening hours in the RG compared with the control group. In conclusion, there was no significant difference in STEMI onset time, but the time from symptom onset to hospital admission was significantly delayed during Ramadan.

The Impact of Meteorological Factors and Air Pollutants on Acute Coronary Syndrome

Purpose of Review

Several studies have found that air pollution and climate change can have an impact on acute coronary syndromes (ACS), the leading cause of death worldwide. We synthesized the latest information about the impact of air pollution and climate change on ACS, the latest data about the pathophysiological mechanisms of meteorological factors and atmospheric pollutants on atherosclerotic disease, and an overall image of air pollution and coronary heart disease in the context of the COVID-19 pandemic.

Recent Findings

The variation of meteorological factors in different seasons increased the risk of ACS. Both the increase and the decrease in apparent temperature were found to be risk factors for ACS admissions. It was also demonstrated that exposure to high concentrations of air pollutants, especially particulate matter, increased cardiovascular morbidity and mortality.

Summary

Climate change as well as increased emissions of air pollutants have a major impact on ACS. The industrialization era and the growing population cause a constant increase in air pollution worldwide. Thus, the number of ACS favored by air pollution and the variations in meteorological factors is expected to increase dramatically in the next few years.

Patient Experience and Perspective on Medical Cannabis as an Alternative for Musculoskeletal Pain Management

Introduction:

The current rate of opioid prescription is disquieting because of their high abuse potential, adverse effects, and thousands of overdose deaths. This situation imposes urgency in seeking alternatives for adequate pain management. From this perspective, this study aimed to evaluate the experience and the perceived analgesic efficacy of medical cannabis in managing the pain associated with musculoskeletal conditions.

Methods:

A 28-question survey was distributed to patients at a major medical cannabis center in Puerto Rico for 2 months. Demographics, medical history, cannabis usage, cannabis use perspective, and analgesic efficacy were assessed in the questionnaire.

Results:

One hundred eighty-four patients completed our survey. The majority (67%) were males, and the participants' average age was 38 years. This study showed an average pain reduction score of 4.02 points on the Numeric Rating Scale among all the participants. Those with musculoskeletal conditions reported a notable average pain reduction score of 4.47 points. In addition, 89% of the participants considered medical cannabis to be more effective than narcotics for adequate pain management.

Conclusions:

This study demonstrated that the use of medical cannabis among patients with musculoskeletal conditions effectively reduced pain levels based on their Numeric Rating Scale reported scores.

Effects of Exercise Training on the Autonomic Nervous System with a Focus on Anti-Inflammatory and Antioxidants Effects

Studies show that the autonomic nervous system (ANS) has an important impact on health in general. In response to environmental demands, homeostatic processes are often compromised, therefore determining an increase in the sympathetic nervous system (SNS)’s functions and a decrease in the parasympathetic nervous system (PNS)’s functions. In modern societies, chronic stress associated with an unhealthy lifestyle contributes to ANS dysfunction. In this review, we provide a brief introduction to the ANS network, its connections to the HPA axis and its stress responses and give an overview of the critical implications of ANS in health and disease—focused specifically on the immune system, cardiovascular, oxidative stress and metabolic dysregulation. The hypothalamic–pituitary–adrenal axis (HPA), the SNS and more recently the PNS have been identified as regulating the immune system. The HPA axis and PNS have anti-inflammatory effects and the SNS has been shown to have both pro- and anti-inflammatory effects. The positive impact of physical exercise (PE) is well known and has been studied by many researchers, but its negative impact has been less studied. Depending on the type, duration and individual characteristics of the person doing the exercise (age, gender, disease status, etc.), PE can be considered a physiological stressor. The negative impact of PE seems to be connected with the oxidative stress induced by effort.

Effects of ambient temperature on cardiovascular disease: a time-series analysis of 229288 deaths during 2009-2017 in Qingdao, China

The association between ambient temperature and cardiovascular mortality varied by regions, populations, and climates. We estimated the relative risk (RR) of cardiovascular mortality using 229,288 death cases of cardiovascular disease in Qingdao China from 1 January 2009, to 31 December 2017. A distributed lag non-linear model was used. The temperature showed a negative association with the cardiovascular mortality. The RR of cardiovascular death at -4.8 °C was 2.05 (95% CI: 1.55, 2.69). The high temperature had acute and short-term effects with the maximum risk occurring 0 day of exposure. The low temperature had the greatest effect on the 4th lag day. The cold temperature effect was stronger for males than females. The estimates of temperature-related cardiovascular mortality risk were higher in people age ≥75 years. Our study showed that the cold and hot ambient temperature had a relationship with the risk of cardiovascular mortality.

Circadian Rhythms, Disease and Chronotherapy

Circadian clocks are biological timing mechanisms that generate 24-h rhythms of physiology and behavior, exemplified by cycles of sleep/wake, hormone release, and metabolism. The adaptive value of clocks is evident when internal body clocks and daily environmental cycles are mismatched, such as in the case of shift work and jet lag or even mistimed eating, all of which are associated with physiological disruption and disease. Studies with animal and human models have also unraveled an important role of functional circadian clocks in modulating cellular and organismal responses to physiological cues (ex., food intake, exercise), pathological insults (e.g. virus and parasite infections), and medical interventions (e.g. medication). With growing knowledge of the molecular and cellular mechanisms underlying circadian physiology and pathophysiology, it is becoming possible to target circadian rhythms for disease prevention and treatment. In this review, we discuss recent advances in circadian research and the potential for therapeutic applications that take patient circadian rhythms into account in treating disease.

A time-series prediction model of acute myocardial infarction in northern of Iran: the risk of climate change and religious mourning

BACKGROUND

Although various studies have been conducted on the effects of seasonal climate changes or emotional variables on the risk of AMI, many of them have limitations to determine the predictable model. The currents study is conducted to assess the effects of meteorological and emotional variables on the incidence and epidemiological occurrence of acute myocardial infarction (AMI) in Sari (capital of Mazandaran, Iran) during 2011-2018.

METHODS

In this study, a time series analysis was used to determine the variation of variables over time. All series were seasonally adjusted and Poisson regression analysis was performed. In the analysis of meteorological data and emotional distress due to religious mourning events, the best results were obtained by autoregressive moving average (ARMA) (5,5) model.

RESULTS

It was determined that average temperature, sunshine, and rain variables had a significant effect on death. A total of 2375 AMI's were enrolled. Average temperate (°C) and sunshine hours a day (h/day) had a statistically significant relationship with the number of AMI's (β = 0.011, P = 0.014). For every extra degree of temperature increase, the risk of AMI rose [OR = 1.011 (95%CI 1.00, 1.02)]. For every extra hour of sunshine, a day a statistically significant increase [OR = 1.02 (95% CI 1.01, 1.04)] in AMI risk occurred (β = 0.025, P = 0.001). Religious mourning events increase the risk of AMI 1.05 times more. The other independent variables have no significant effects on AMI's (P > 0.05).

CONCLUSION

Results demonstrate that sunshine hours and the average temperature had a significant effect on the risk of AMI. Moreover, emotional distress due to religious morning events increases AMI. More specific research on this topic is recommended.

Acute Myocardial Infarction and Daylight Saving Time Transitions: Is There a Risk?

Available evidence on the risk of acute myocardial infarction (AMI) in the days after the spring daylight saving time (DST) transition suggests either a modest increase or no risk increase. Partial sleep deprivation and enhanced circadian clock misalignment have been implicated as the underlying mechanisms for increased AMI risk, probably via enhanced thrombo-inflammatory processes and activation of the sympathetic nervous system. Most of the studies, as we suggest as a perspective here, have used potentially inappropriate control periods, including the two post-transitional weeks, because adjustment after the spring DST transition lasts at least four weeks for all chronotypes and probably even beyond this period for late chronotypes. The most plausible conclusions, at the moment, for the risk of AMI after the spring DST transition are: (1) the risk is increased, (2) a relatively modest risk increase could be currently underestimated or in some studies undetected, (3) late chronotypes and/or individuals with high levels of social jetlag (a proxy for circadian clock misalignment) could be more affected by the phenomenon, and (4) underlying pathophysiological mechanisms should be further explored. As a significant part of world’s population continues to be affected by the biannual clock change, the question of increased AMI risk in the post-transitional period remains an intriguing public health issue.

Christmas holiday triggers of myocardial infarction

Objectives: Christmas holidays have been associated with the highest incidence of myocardial infarction (MI). We wanted to assess possible triggers of MI during Christmas. Design: A nationwide, retrospective postal survey with case-control design. All individuals suffering an MI during the Christmas holidays 2018 and 2019 in Sweden were identified through the SWEDEHEART registry and a control group matched in age and gender with chronic coronary syndrome who did not seek medical attention during Christmas were asked for participation. Subjects completed a questionnaire asking them to rate 27 potential MI-triggers as having occurred more or less than usual. Results: A total of 189 patients suffering an MI on Christmas Eve, Christmas Day, or Boxing Day, and 157 patients in the control group responded to the questionnaire, representing response rates of 66% and 62%, respectively. Patients with MI on Christmas experienced more stress (37% vs. 21%, p = .002), depression (21% vs. 11%, p = .024), and worry (26% vs. 10%, p < .001) compared to the control group. The food and sweets consumption was increased in both groups, but to a greater extent in the control group (33% vs. 50%, p = .002 and 32% vs. 43%, p = .031). There were no increases in quarrels, anger, economic worries, or reduced compliance with medication. Conclusions: Patients suffering MI on Christmas holiday experienced higher levels of stress and emotional distress compared to patients with chronic coronary syndrome, possibly contributing to the phenomenon of holiday heart attack. Understanding what factors increase the number of MI on Christmas may help reduce the excess number of MIs and cardiovascular burden.

Mortality due to circulatory causes in hot and cold environments in Greece

Ambient temperature can affect the survival rate of humans. Studies have shown a relationship between ambient temperature and mortality rate in hot and cold environments. This effect of ambient temperature on mortality seems to be more pronounced in older people. The aim of this study is to examine the effects of thermal stress on cardiovascular mortality and the associated relative risk per degree Celsius in Greek individuals ≥70 years old. Mortality data 1999-2012 were matched with the midday temperature. The present study found a higher circulatory mortality when ambient temperature is below or above the temperature range 6 to 39 °C.

The effectiveness of planned discharge education on health knowledge and beliefs in patients with acute myocardial infarction: a randomized controlled trial

BACKGROUND

To the best of our knowledge, no other studies investigated acute myocardial infarction patients' beliefs and knowledge level after the discharge education.

AIMS

The aim of the study was to investigate the effectiveness of planned discharge education on the beliefs and knowledge levels of CVD risk factors, medication compliance, dietary compliance, and individual follow-up in patients with acute myocardial infarction (AMI).

METHODS

A double-blind randomized controlled study was carried out with 100 AMI patients. All participants were randomly assigned to the intervention (n = 50) and control groups (n = 50). The first evaluation of all participants in both groups was on the day of discharge. Both groups were re-evaluated after 4 weeks. Patients' beliefs on medication, diet, and individual monitoring were assessed by the Beliefs about Medication Compliance Scale (BMCS), the Beliefs about Dietary Compliance Scale (BDCS), and the Beliefs about Individual Follow-up Scale (BIFS), respectively. The knowledge of CVD risk factors was questioned with the Cardiovascular Disease Risk Factors Knowledge Level (CARRF-KL) Scale.

RESULTS

The mean age of the patients was 59.10 ± 9.38 years in the intervention group and 58.86 ± 9.19 in the control group. After the planned discharge education, beliefs and knowledge levels of CVD risk factors, medication compliance, dietary compliance, and individual follow-up were significantly increased compared with the control group.

CONCLUSION

Planned discharge education had a positive effect on the knowledge level of cardiovascular diseases risk factors, drug compliance, nutritional compliance, and individual follow-up in patients with acute myocardial infarction.

Public health impact of daily life triggers of sudden cardiac death: A systematic review and comparative risk assessment

BACKGROUND

Sudden cardiac death (SCD) may be triggered by daily circumstances and activities such as stressful psycho-emotional events, physical exertion or substance misuse. We calculated population attributable fractions (PAFs) to estimate the public health relevance of daily life triggers of SCD and to compare their population impacts.

METHODS

We searched PubMed, Scopus and the Web of Science citation databases to retrieve studies of triggers of SCD and cardiac arrest that would enable a computation of PAFs. When more studies investigated the same trigger, a meta-analytical pooled risk random-effect estimate was used.

RESULTS

Of the retrieved studies, eight provided data enabling computation of PAFs. The prevalence of exposure within population for SCD triggers in the control periods ranged from 1.06% for influenza infection to 8.73% for recent use of cannabis. Triggers ordered from the highest to the lowest risk increase were: physical exertion, recent cocaine use, episodic alcohol consumption, recent amphetamine use, episodic coffee consumption, psycho-emotional stress within the previous month, influenza infection, and recent cannabis use. The relative risk increase ranged from 1.10 to 4.98. By accounting for both the magnitude of the risk increase and the prevalence in the population, the present estimates of PAF assign 14.5% (95% confidence interval [CI] 4.9-28.5) of all SCDs to episodic alcohol consumption, 9.4% (95% CI 1.2-29.3) to physical exertion, 6.9% (95% CI 0.3-25.0) to cocaine, 6% (95% CI 1.2-14.6) to episodic coffee consumption, 3% (95% CI 0.4-6.8) to psycho-emotional stress in the previous month, 1.7% (95% CI -0.9 to 12.9) to amphetamines, 0.9% (95% CI -4.9 to 12.5) to cannabis, and 0.3% (95% CI 0.2-0.4) to influenza infections.

CONCLUSIONS

In addition to episodic alcohol consumption, a trigger with the greatest public health importance for SCD, episodic physical exertion, cocaine use and coffee consumption also show a considerable population impact.

Leptin increases sympathetic nerve activity via induction of its own receptor in the paraventricular nucleus

Whether leptin acts in the paraventricular nucleus (PVN) to increase sympathetic nerve activity (SNA) is unclear, since PVN leptin receptors (LepR) are sparse. We show in rats that PVN leptin slowly increases SNA to muscle and brown adipose tissue, because it induces the expression of its own receptor and synergizes with local glutamatergic neurons. PVN LepR are not expressed in astroglia and rarely in microglia; instead, glutamatergic neurons express LepR, some of which project to a key presympathetic hub, the rostral ventrolateral medulla (RVLM). In PVN slices from mice expressing GCaMP6, leptin excites glutamatergic neurons. LepR are expressed mainly in thyrotropin-releasing hormone (TRH) neurons, some of which project to the RVLM. Injections of TRH into the RVLM and dorsomedial hypothalamus increase SNA, highlighting these nuclei as likely targets. We suggest that this neuropathway becomes important in obesity, in which elevated leptin maintains the hypothalamic pituitary thyroid axis, despite leptin resistance.

Cannabis Use Is an Independent Predictor for Acute Myocardial Infarction Related Hospitalization in Younger Population

PURPOSE

This study aimed to evaluate the risk of various substances in young acute myocardial infarction (AMI) inpatients and analyze patient demographics and hospital outcomes for significant substance use risk factors.

METHODS

We conducted a retrospective analysis of the Nationwide Inpatient Sample data (2010-2014). Patients (aged 15-22 years) with a primary diagnosis for AMI (N = 1,694) were compared with non-AMI (N = 9,465,255) inpatients for odds ratio (OR) of substance use by logistic regression model, adjusted for demographics, medical risk factors, and comorbid substance use.

RESULTS

Tobacco (28.4%) and cannabis (14.9%) use were most prevalent in AMI inpatients. Cocaine (OR = 3.9), amphetamine (OR = 2.3), and cannabis (OR = 1.3) users were at higher risk of AMI hospitalizations. Higher proportion of cannabis users (14.7%) had major severity of illness at admission and higher mean total charge ($53,608) compared with that seen in cocaine and amphetamine users. Angioplasty was used more in cannabis users (19.4%) than others. The in-hospital mortalities were 2.7% and 2% in overall AMI cohort and cannabis users, respectively, and none in cocaine and amphetamine users.

CONCLUSIONS

Our study demonstrates a higher prevalence and significant odds of AMI inpatients with cannabis use, along with the potential cost burdens because of severe morbidity and higher use of treatment modalities. Physicians need to familiarize themselves with rising use of cannabis and other substances in adolescent and younger population and the typical presentations of cannabis-induced myocardial infarction.

CANNABIS USE INCREASES RISK FOR REVISION AFTER TOTAL KNEE ARTHROPLASTY

As an increasing number of states begin to legalize marijuana for either medical or recreational use, it is important to determine its effects on joint arthroplasty. The purpose of this study is to determine the impact of cannabis use on total knee arthroplasty (TKA) revision incidence, revision causes, and time to revision by analyzing the Medicare database between 2005 and 2014. A retrospective review of the Medicare database for TKA, revision TKA, and causes was performed utilizing Current Procedural Terminology (CPT) and International Classification of Disease ninth revision codes (ICD-9). Patients who underwent TKA were cross-referenced for a history of cannabis use by querying ICD-9 codes 304.30-32 and 305.20-22. The resulting group was then longitudinally tracked postoperatively for revision TKA. Cause for revision, time to revision, and gender were also investigated. Our analysis returned 2,718,023 TKAs and 247,112 (9.1%) revisions between 2005 and 2014. Cannabis use was prevalent in 18,875 (0.7%) of TKA patients with 2,419 (12.8%) revisions within the cannabis cohort. Revision incidence was significantly greater in patients who use cannabis (p < 0.001). Time to revision was also significantly decreased in patients who used cannabis, with increased 30- and 90-day revision incidence compared to the noncannabis group (P < 0.001). Infection was the most common cause of revision in both groups (33.5% nonusers versus 36.6% cannabis users).Cannabis use may result in decreasing implant survivorship and increasing the risk for revision within the 90-day global period compared to noncannabis users following primary TKA.

Cultural factors and the circadian rhythm of ST elevation myocardial infarction in patients in a Mediterranean island

INTRODUCTION

The circadian rhythm of onset of myocardial infarction shows an increased risk during the morning hours. However, it is not clear whether habits, culture and sunshine hours differentiate circadian rhythm. The aim of this study was to investigate the influence of cultural factors on the circadian rhythm of acute myocardial infarction with ST segment elevation in a Mediterranean island.

METHOD

The study was a retrospective correlational survey. It included 123 patients with ST elevation myocardial infarction (mean age 60.7±12.6; 82% men). The 24 h of a day were divided into four six-hour periods of time for study purposes (00:01-06:00; 06:01-12:00; 12:01-18:00; and 18:01-24:00) and the chi-square test was used for the analysis.

RESULTS

A morning peak of symptoms onset of ST-elevation myocardial infarction was detected during the period 06:01-12:00 (p=0.044). In patients who were smokers, a bimodal pattern involving a morning (06:01-12:00) and an afternoon-to-night peak (18:01-24:00) (p=0.005) was detected. For patients with a history of hypertension, a morning peak of their symptoms was also detected (p=0.028). Different circadian variations were found between patients over the age of 60 years old and patients under the age of 60 years old (p=0.025).

CONCLUSIONS

Patients with ST elevation myocardial infarction seem to follow a circadian rhythm with a peak of onset of symptoms in the morning. In the smokers' subgroup, a different circadian pattern was found. The habit of smoking is likely to affect the circadian rhythm of the onset of ST elevation myocardial infarction in the Mediterranean area and culture.

Exposure to Total Hydrocarbons During Cleanup of the Deepwater Horizon Oil Spill and Risk of Heart Attack Across 5 Years of Follow-up

Exposure to total hydrocarbons (THC) and volatile organic compounds from air pollution is associated with risk of coronary heart disease. THC exposure from oil spills might be similarly associated, but no research has examined this. We assessed the relationship between THC exposure during the response and cleanup of the Deepwater Horizon oil spill (Gulf of Mexico) and heart attack risk among 24,375 oil spill workers enrolled in the Gulf Long-Term Follow-up Study. There were 312 first heart attacks (self-reported physician-diagnosed myocardial infarction, or fatal coronary heart disease) ascertained during the study period (2010-2016). THC exposures were estimated using a job-exposure matrix incorporating self-reported activities and personal air measurements. We used Cox proportional hazards regression to estimate hazard ratios, with inverse-probability weights to account for confounding and censoring. Maximum THC levels of ≥0.30 parts per million (ppm) were associated with heart attack risk, with a 1.8-fold risk for exposure of ≥3.00 ppm versus <0.30 ppm (hazard ratio = 1.81, 95% confidence interval: 1.11, 2.95). The risk difference for highest versus lowest THC level was 10 excess cases per 1,000 workers. This is the first study of the persistent health impacts of THC exposure during oil spill work, and results support increased protection against oil exposure during cleanup of future spills.

Sex differences in the sympathoexcitatory response to insulin in obese rats: role of neuropeptide Y

KEY POINTS

Intracerebroventricular insulin increased sympathetic nerve activity (SNA) and baroreflex control of SNA and heart rate more dramatically in obese male rats; in obese females, the responses were abolished. In obese males, the enhanced lumbar SNA (LSNA) responses were associated with reduced tonic inhibition of LSNA by neuropeptide Y (NPY) in the PVN. However, PVN NPY injection decreased LSNA similarly in obesity prone/obesity resistant/control rats. Collectively, these results suggest that NPY inputs were decreased. In obese females, NPY inhibition in the PVN was maintained. Moreover, NPY neurons in the arcuate nucleus became resistant to the inhibitory effects of insulin. A high-fat diet did not alter arcuate NPY neuronal InsR expression in males or females. Obesity-induced 'selective sensitization' of the brain to the sympathoexcitatory effects of insulin and leptin may contribute to elevated basal SNA, and therefore hypertension development, in males with obesity. These data may explain in part why obesity increases SNA less in women compared to men.

ABSTRACT

Obesity increases sympathetic nerve activity (SNA) in men but not women; however, the mechanisms are unknown. We investigated whether intracerebroventricular insulin infusion increases SNA more in obese male than female rats and if sex differences are mediated by changes in tonic inhibition of SNA by neuropeptide Y (NPY) in the paraventricular nucleus (PVN). When consuming a high-fat diet, obesity prone (OP) rats accrued excess fat, whereas obesity resistant (OR) rats maintained adiposity as in rats eating a control (CON) diet. Insulin increased lumbar SNA (LSNA) similarly in CON/OR males and females under urethane anaesthesia. The LSNA response was magnified in OP males but abolished in OP females. In males, blockade of PVN NPY Y1 receptors with BIBO3304 increased LSNA in CON/OR rats but not OP rats. Yet, PVN nanoinjections of NPY decreased LSNA similarly between groups. Thus, tonic PVN NPY inhibition of LSNA may be lost in obese males as a result of a decrease in NPY inputs. By contrast, in females, PVN BIBO3304 increased LSNA similarly in OP, OR and CON rats. After insulin, PVN BIBO3304 failed to increase LSNA in CON/OR females but increased LSNA in OP females, suggesting that with obesity NPY neurons become resistant to the inhibitory effects of insulin. These sex differences were not associated with changes in arcuate NPY neuronal insulin receptor expression. Collectively, these data reveal a marked sex difference in the impact of obesity on the sympathoexcitatory actions of insulin and implicate sexually dimorphic changes in NPY inhibition of SNA in the PVN as one mechanism.

Deepwater Horizon oil spill exposures and nonfatal myocardial infarction in the GuLF STUDY

BACKGROUND

Workers involved in the response and clean-up of the 2010 Deepwater Horizon oil spill faced possible exposures to crude oil, burning oil, dispersants and other pollutants in addition to physical and emotional stress. These exposures may have increased risk of myocardial infarction (MI) among oil spill workers.

METHODS

Gulf Long-term Follow-up (GuLF) STUDY participants comprise individuals who either participated in the Deepwater Horizon response efforts or registered for safety training but were not hired. Oil spill-related exposures were assessed during enrollment interviews conducted in 2011-2013. We estimated risk ratios (RR) and 95% confidence intervals for the associations of clean-up work characteristics with self-reported nonfatal MI up to three years post-spill.

RESULTS

Among 31,109 participants without history of MI prior to the spill, 77% worked on the oil spill. There were 192 self-reported MI during the study period; 151 among workers. Among the full cohort, working on the oil spill clean-up (vs not working on the clean-up) and living in proximity to the oil spill (vs further away) were suggestively associated with a possible increased risk of nonfatal MI [RR: 1.22 (0.86, 1.73) and 1.15 (0.82, 1.60), respectively]. Among oil spill workers, working for > 180 days was associated with MI [RR for > 180 days (vs 1-30 days): 2.05 (1.05, 4.01)], as was stopping working due to heat [RR: 1.99 (1.43, 2.78)]. There were suggestive associations of maximum total hydrocarbon exposure ≥3.00 ppm (vs < 0.30 ppm) [RR: 1.69 (0.90, 3.19)] and working on decontaminating oiled equipment (vs administrative support) [1.72 (0.96, 3.09)] with nonfatal MI.

CONCLUSION

This is the first study to assess the associations between oil spill exposures and MI. Results suggest that working on the spill for > 180 days and stopping work due to heat increased risk of nonfatal MI. Future research should evaluate whether the observed associations are related to specific chemical exposures or other stressors associated with the spill.

The association between exposure to air pollutants including PM10, PM2.5, ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide concentration and the relative risk of developing STEMI: A case-crossover design

BACKGROUND

Unfavorable associations between air pollution and myocardial infarction are broadly investigated in recent studies and some of them revealed considerable associations; however, controversies exists between these investigations with regard to culprit components of air pollution and significance of correlation between myocardial infarction risk and air pollution.

METHODS

The association between exposure to PM₁₀, PM_2.5, ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide concentration of background air that residents of Tehran, the capital city of Iran, which is ranked as the most air polluted city of Iran and the relative risk of developing ST-elevation myocardial infarction (STEMI) were investigated by a case-crossover design. Our study included 208 patients admitted with a diagnosis of STEMI and undergone primary percutaneous intervention. Air pollutant concentration was averaged in 24-h windows preceding the time of onset of myocardial infarction for the case period. Besides, the mean level of each element of air pollution of the corresponding time in one week, two weeks and three weeks before onset of myocardial infarction, was averaged separately for each day as one control periods. Thus, 624 control periods were included in our investigation such that. Each patient is matched and compared with him/herself.

RESULTS

The mean level of PM₁₀ in case periods (61.47µg/m³) was significantly higher than its level in control periods (57.86µg/m³) (P-value = 0.019, 95% CI: 1.002-1.018, RR = 1.010). Also, the mean level of PM_2.5 in case periods (95.40µg/m³) was significantly higher than that in control days (90.88µg/m³) (P-value = 0.044, 95% CI: 1.001-1.011, RR = 1.006). The level of other components including NO₂, SO₂, CO and O₃ showed no significant differences between case and control periods. A 10µg/m³ increase in PM₁₀ and PM_2.5 would result in 10.10% and 10.06% increase in STEMI event, respectively. Furthermore, the results of sub-group analysis showed that older patients (equal or more than 60 year-old), diabetic patients, non-hypertensive ones and patients with more than one diseased vessel may be more vulnerable to the harmful effect of particular matters including PM₁₀ and PM_2.5 on development of STEMI.

CONCLUSION

Air pollution is a worldwide pandemic with great potential to cause terrible events especially cardiovascular ones. PM_2.5 and PM₁₀ are amongst ambient air pollutant with a high risk of developing STEMI. Thus, more restrictive legislations should be applied to define a safe level of indoor and outdoor air pollutant production.

Acute triggers of myocardial infarction: A case-crossover study

BACKGROUND

Acute myocardial infarction (AMI) is one of the most preventable non-communicable diseases in human. Identifying triggers of myocardial infarction (MI) and prevention ways of exposure-induced complications can reduce morbidity and mortality in people at risk.

AIM

The aim of this study was to identify the emotional, environmental, physical and chemical dimensions of acute triggers in patients with AMI.

METHODS

This case-crossover study was conducted on 269 patients with AMI, hospitalized at two remedial centers in Rasht in 2015. The study samples were selected by convenient sampling method. Data were collected using researcher-made questionnaire through interviews. Hazard and control periods for each trigger and its effects on the development of MI were studied. The collected data were analyzed using descriptive and analytical statistical methods, Cochran test, and generalized estimating equation (GEE) model with logistics function default in SPSS version 21, and p < 0.05 was considered statistically significant.

RESULTS

The results showed that quarrel (P = 0.008, OR = 2.01) and hearing the sudden news (P = 0.001, OR = 2.19) were the most common emotional triggers. Respiratory infections (P = 0.0001, OR = 6.78) and exposure to hot or cold weather (P = 0.005, OR = 2.19) were the most frequent environmental triggers. Doing heavy activities (P = 0.005, OR = 1.66) and sexual activities (P = 0.003, OR = 2.36) were among the most common physical triggers. High-fat foods consumption and overeating (P = 0.0001, OR = 3.79) were the most frequent chemical triggers of AMI.

CONCLUSION

It seems that given the importance of the triggers in the incidence of AMI, planning is necessary to train vulnerable individuals to reduce exposure to triggers.

Ambient temperature and cardiovascular mortality: a systematic review and meta-analysis

INTRODUCTION

Our study aims at identifying and quantifying the relationship between the cold and heat exposure and the risk of cardiovascular mortality through a systematic review and meta-analysis.

MATERIAL AND METHODS

A systematic review and meta-analysis were conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Peer-reviewed studies about the temperature and cardiovascular mortality were retrieved in the MEDLINE, Web of Science, and Scopus databases from January 2000 up to the end of 2015. The pooled effect sizes of short-term effect were calculated for the heat exposure and cold exposure separately. Also, we assessed the dose-response relationship of temperature-cardiovascular mortality by a change in units of latitudes, longitude, lag days and annual mean temperature by meta-regression.

RESULT

After screening the titles, abstracts and full texts, a total of 26 articles were included in the meta-analysis. The risk of cardiovascular mortality increased by 5% (RR, 1.055; 95% CI [1.050-1.060]) for the cold exposure and 1.3% (RR, 1.013; 95% CI [1.011-1.015]) for the heat exposure. The short-term effects of cold and heat exposure on the risk of cardiovascular mortality in males were 3.8% (RR, 1.038; 95% CI [1.034-1.043]) and 1.1%( RR, 1.011; 95% CI [1.009-1.013]) respectively. Moreover, the effects of cold and heat exposure on risk of cardiovascular mortality in females were 4.1% (RR, 1.041; 95% CI [1.037-1.045]) and 1.4% (RR, 1.014; 95% CI [1.011-1.017]) respectively. In the elderly, it was at an 8.1% increase and a 6% increase in the heat and cold exposure, respectively. The greatest risk of cardiovascular mortality in cold temperature was in the 14 lag days (RR, 1.09; 95% CI [1.07-1.010]) and in hot temperatures in the seven lag days (RR, 1.14; 95% CI [1.09-1.17]). The significant dose-response relationship of latitude and longitude in cold exposure with cardiovascular mortality was found. The results showed that the risk of cardiovascular mortality increased with each degree increased significantly in latitude and longitude in cold exposure (0.2%, 95% CI [0.006-0.035]) and (0.07%, 95% CI [0.0003-0.014]) respectively. The risk of cardiovascular mortality increased with each degree increase in latitude in heat exposure (0.07%, 95% CI [0.0008-0.124]).

CONCLUSION

Our findings indicate that the increase and decrease in ambient temperature had a relationship with the cardiovascular mortality. To prevent the temperature- related mortality, persons with cardiovascular disease and the elderly should be targeted. The review has been registered with PROSPERO (registration number CRD42016037673).

Baseline aortic pulse wave velocity is associated with central and peripheral pressor responses during the cold pressor test in healthy subjects

Cold environmental temperatures increase sympathetic nerve activity and blood pressure, and increase the risk of acute cardiovascular events in aged individuals. The acute risk of cardiovascular events increases with aortic pulse wave velocity as well as elevated central and peripheral pulse pressures. The aim of this study was to examine the independent influence of aortic pulse wave velocity upon central and peripheral pressor responses to sympathetic activation via the cold pressor test (CPT). Twenty‐two healthy subjects (age: 18–73 years) completed a CPT with the left hand immersed in 2–4°C water for 3 min. During the CPT, central (from: 36 ± 7 to: 51 ± 12 mmHg) and peripheral pulse pressure increased (from: 54 ± 7 to: 66 ± 11; both P < 0.05). In all subjects the increase in central pulse pressure during the CPT was independently associated with baseline aortic pulse wave velocity (r² = 0.221, P = 0.027) but not age (P > 0.05). In a subset of subjects with higher arterial stiffness, the increase in peripheral pulse pressure during the CPT was independently associated with baseline aortic pulse wave velocity (r² = 0.415, P = 0.032) but not age (P > 0.05). These data indicate that central and peripheral pulse pressure responses during sympathetic activation are positively and independently associated with aortic pulse wave velocity through a wide age range. Decreasing aortic pulse wave velocity in aged individuals with elevated arterial stiffness may help reduce the incidence of acute cardiovascular events upon exposure to cold environmental temperatures.

Impact of long-hours family caregiving on non-fatal coronary heart disease risk in middle-aged people: Results from a longitudinal nationwide survey in Japan

AIM

The effects of family caregiving, especially long-hours caregiving, on coronary heart disease (CHD) are debatable. We examined the impact of family caregiving on incident non-fatal CHD.

METHODS

We used data from the Longitudinal Survey of Middle-Aged and Elderly Persons from 2005 to 2010, a nationwide panel survey for Japanese people aged 50-59 years in 2005 (baseline). After we excluded non-respondents and people with missing key variables at baseline, 25 121 individuals without CHD, stroke or cancer were followed up for a mean of 4.6 years. The exposure was assessed at baseline by three indicators: (i) family caregiving; (ii) hours spent caregiving; and (iii) kinship type of care recipient. The non-fatal CHD incidence was identified according to questionnaire responses from 2006 to 2010.

RESULTS

Cox's proportional hazards analysis did not show a statistically significant association between family caregiving and incident non-fatal CHD (hazard ratio [HR] 1.13, 95% confidence interval [CI] 0.92-1.40). Caregivers who spent 20-69 h per week on care showed a statistically significant increased risk for non-fatal CHD (HR 1.78, 95% CI 1.23-2.58) compared with non-caregivers; whereas this increased risk was statistically significant only among women (HR 1.98, 95% CI 1.27-3.08), but not among men (HR 1.35, 95% CI 0.67-2.71). Kinship type of care recipient did not make a significant difference to the effects of family caregiving on incident non-fatal CHD.

CONCLUSIONS

Long-hours family caregiving could be an independent risk factor for incident non-fatal CHD among middle-aged women in Japan. Geriatr Gerontol Int 2017; 17: 2109-2115.

The clinics of acute coronary syndrome

Risk stratification and management of patients with chest pain continues to be challenging despite considerable efforts made in the last decades by many clinicians and researchers. The throutful evaluation necessitates that the physicians have a high index of suspicion for acute coronary syndrome (ACS) and always keep in mind the myriad of often subtle and atypical presentations of ischemic heart disease, especially in certain patient populations such as the elderly ones. In this article we aim to review and discuss the available evidence on the value of clinical presentation in patients with a suspected ACS, with special emphasis on history, characteristics of chest pain, associated symptoms, atypical presentations, precipitating and relieving factors, drugs, clinical rules and significance of clinical Gestalt.

Association of daylight saving time transitions with incidence and in-hospital mortality of myocardial infarction in Finland

INTRODUCTION

Circadian rhythm disturbance increases cardiovascular risk but the effects of daylight saving time (DST) transitions on the risk of myocardial infarction (MI) are unclear.

METHODS

We studied association of DST transitions in 2001-2009 with incidence and in-hospital mortality of MI admissions nationwide in Finland. Incidence rations (IR) of observed incidences on seven days following DST transition were compared to expected incidences.

RESULTS

Incidence of MI increased on Wednesday (IR 1.16; CI 1.01-1.34) after spring transition (6298 patients' cohort). After autumn transition (8161 patients' cohort), MI incidence decreased on Monday (IR 0.85; CI 0.74-0.97) but increased on Thursday (IR 1.15; CI 1.02-1.30). The overall incidence of MI during the week after each DST transition did not differ from control weeks. Patient age or gender, type of MI or in-hospital mortality were not associated with transitions. Renal insufficiency was more common among MI patients after spring transition (OR 1.81; CI 1.06-3.09; p < 0.05). Diabetes was less common after spring transition (OR 0.71; CI 0.55-0.91; p = 0.007), but more common after autumn transition (OR 1.21; 1.00-1.46; p < 0.05).

CONCLUSIONS

DST transitions are followed by changes in the temporal pattern but not the overall rate of MI incidence. Comorbidities may modulate the effects DST transitions.

Associations between short-term exposure to particulate matter and ultrafine particles and myocardial infarction in Augsburg, Germany

BACKGROUND

Short-term exposure to increased particulate matter (PM) concentration has been reported to trigger myocardial infarction (MI). However, the association with ultrafine particles remains unclear.

OBJECTIVES

We aimed to assess the effects of short-term air pollution and especially ultrafine particles on registry-based MI events and coronary deaths in the area of Augsburg, Germany.

METHODS

Between 1995 and 2009, the MONICA/KORA myocardial infarction registry recorded 15,417 cases of MI and coronary deaths. Concentrations of PM<10μm (PM10), PM<2.5μm (PM2.5), particle number concentration (PNC) as indicator for ultrafine particles, and meteorological parameters were measured in the study region. Quasi-Poisson regression adjusting for time trend, temperature, season, and weekday was used to estimate immediate, delayed and cumulative effects of air pollutants on the occurrence of MI. The daily numbers of total MI, nonfatal and fatal events as well as incident and recurrent events were analysed.

RESULTS

We observed a 1.3% risk increase (95%-confidence interval: [-0.9%; 3.6%]) for all events and a 4.4% [-0.4%; 9.4%] risk increase for recurrent events per 24.3μg/m(3) increase in same day PM10 concentrations. Nonfatal events indicated a risk increase of 3.1% [-0.1%; 6.5%] with previous day PM10. No association was seen for PM2.5 which was only available from 1999 on. PNC showed a risk increase of 6.0% [0.6%; 11.7%] for recurrent events per 5529 particles/cm(3) increase in 5-day average PNC.

CONCLUSIONS

Our results suggested an association between short-term PM10 concentration and numbers of MI, especially for nonfatal and recurrent events. For ultrafine particles, risk increases were notably high for recurrent events. Thus, persons who already suffered a MI seemed to be more susceptible to air pollution.

Triggers of acute myocardial infarction: a neglected piece of the puzzle

The existence of specific risk factors for the development of coronary heart disease, both chronic and acute, has been extensively investigated and is well understood by cardiology professionals. Diabetes, hypertension, hypercholesterolemia, psychological patterns and smoking are assumed to interact in a complex way with individual heritable predisposition, thus determining the long-term probability of coronary disease. However, the possibility that defined circumstances and activities may act as immediate triggers of acute coronary syndromes, particularly acute myocardial infarction, has not been given comparable attention in clinical research. For example, the recently issued 2012 European guidelines on cardiovascular disease prevention completely overlook the topic of triggers and their possible prevention. This review presents a picture of the most reliable evidence regarding the triggering of myocardial infarction and contributes to further investigation in the field.

SEDASYS(®), airway, oxygenation, and ventilation: anticipating and managing the challenges

In May 2013, the FDA (Federal Drug Administration) approved SEDASYS(®), a device that enables non-anesthesia physicians to provide mild-to-moderate sedation to patients undergoing colonoscopy and esophagogastroduodenoscopy. SEDASYS(®) is the first among the devices being built to provide computer-assisted personalized sedation. Although the intention of this approval is to cut the anesthesia related expenses, it is likely to create new challenges to the users-both clinical and administrative-that might even increase the cost. Deep sedation is required frequently for a successful completion of the procedure, which poses unforeseen challenges. The present review aims to provide clear information to the users regarding pre-procedure assessment, possible sedation related complications and management options.

Evaluation of Phyllanthus emblica extract on cold pressor induced cardiovascular changes in healthy human subjects

Background:

Acute and chronic stress is a risk factor for the development and progression of coronary artery disease. Increased arterial stiffness is an independent marker for cardiovascular disease. Cold pressor test (CPT) is known to be associated with substantial activation of the autonomic nervous system.

Objective:

The aim of this study was to evaluate the effect of Phyllanthus emblica extract on cold pressor stress test induced changes on cardiovascular parameters and aortic wave reflections in healthy human subjects.

Materials and Methods:

This was a double-blind, placebo-controlled, crossover study. Participants were randomized to receive either two capsules of P. emblica extract 250 mg (containing aqueous extract of P. emblica, highly standardized by high-performance liquid chromatography to contain low molecular weight hydrolysable tannins emblicanin-A, emblicanin-B, pedunculagin and punigluconin) or two capsules of placebo twice daily for 14 days. Pharmacodynamic parameters such as heart rate, augmentation pressure, augmentation index (AIx), subendocardial viability ratio (SEVR), radial and aortic blood pressure (BP) were recorded before and after CPT at baseline and end of treatment. After washout period of 14 days, subjects crossed over to the other treatment and the same test procedure was repeated again. Safety assessments were done at baseline and at the end of treatment.

Results:

A total of 12volunteers completed the study. Compared with baseline and placebo, P. emblica extract produced a significant decrease of mean percent change in the indices of arterial stiffness (AIx, radial and aortic BP) and increase in SEVR, an index of myocardial perfusion with CPT. Both treatments were well-tolerated and no serious adverse events were reported.

Conclusion:

Proprietary P. emblica extract, showed a significant decrease in cold pressor stress test induced changes on aortic wave reflections.

Low erythrocyte catalase enzyme activity is correlated with high serum total homocysteine levels in Tunisian patients with acute myocardial infarction

Background

An imbalance between pro-oxidants and antioxidant systems has been suggested to be implicated in the physiopathology of acute myocardial infarction (AMI). We aimed to evaluate the antioxidant capacity in Tunisian patients and to assess the possible relationship between erythrocyte catalase enzyme activity and hyperhomocysteinaemia.

Methods

108 patients with AMI and 81 healthy subjects were enrolled in this study. Catalase erythrocyte enzyme activity was determined spectrophotometrically whereas “total antioxidant status” (TAS) concentration was measured by a commercially available method. Serum total homocysteine (tHcy) level was determined by a fluorescence polarization immunoassay (FPIA). Lipid peroxidation was measured with a fluorimetric method as “thiobarbituric acid reactive substances” (TBARS).

Results

Compared with healthy subjects, patients with AMI had significantly lower catalase activity (P<0.001), TAS concentrations (P<0.001), and significantly higher serum tHcy (P<0.001) and TBARS levels (P<0.001). Erythrocyte catalase enzyme activity was negatively correlated with serum tHcy and TBARS while serum tHcy and TBARS were in positive correlation. Furthermore, the unbalance between pro-oxidants and antioxidants seems to be more aggravated in patients with Q wave AMI compared to patients with non-Q wave AMI.

Conclusion

Our results suggest the involvement of hyperhomocysteinaemia in the drop of erythrocyte catalase activity related to myocardial ischemia reperfusion. Hyperhomocysteinaemia may increase the myocardial wall dysfunction under ischemia reperfusion by excessive production of reactive oxygen species which is made evident by increased lipid peroxidation.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1623509866881834

Head and neck cooling decreases tympanic and skin temperature, but significantly increases blood pressure

BACKGROUND AND PURPOSE

Localized head and neck cooling might be suited to induce therapeutic hypothermia in acute brain injury such as stroke. Safety issues of head and neck cooling are undetermined and may include cardiovascular autonomic side effects that were identified in this study.

METHODS

Ten healthy men (age 35±13 years) underwent 120 minutes of combined head and neck cooling (Sovika, HVM Medical). Before and after onset of cooling, after 60 and 120 minutes, we determined rectal, tympanic, and forehead skin temperatures, RR intervals, systolic and diastolic blood pressures (BP), laser-Doppler skin blood flow at the index finger and cheek, and spectral powers of mainly sympathetic low-frequency (0.04-0.15 Hz) and parasympathetic high-frequency (0.15-0.5 Hz) RR interval oscillations and sympathetic low-frequency oscillations of BP. We compared values before and during cooling using analysis of variance with post hoc analysis; (significance, P<0.05).

RESULTS

Forehead skin temperature dropped by 5.5±2.2°C with cooling onset and by 12.4±3.2°C after 20 minutes. Tympanic temperature decreased by 4.7±0.7°C within 40 minutes, and rectal temperature by only 0.3±0.3°C after 120 minutes. Systolic and diastolic BP increased immediately on cooling onset and rose by 15.3±20.8 mm Hg and 16.5±13.4 mm Hg (P=0.004) after 120 minutes, whereas skin blood flow fell significantly during cooling. RR intervals and parasympathetic RR interval high-frequency powers increased with cooling onset and were significantly higher after 60 and 120 minutes than they were before cooling.

CONCLUSIONS

Head and neck cooling prominently reduced tympanic temperature and thus might also induce intracerebral hypothermia; however, it did not significantly lower body core temperature. Profound skin temperature decrease induced sympathetically mediated peripheral vasoconstriction and prominent BP increases that are not offset by simultaneous parasympathetic heart rate slowing. Prominent peripheral vasoconstriction and BP increase must be considered as possibly harmful during head and neck cooling.