Admissions for myocardial infarction and World Cup football: database survey

Acute risk factors for myocardial infarction

Increased knowledge concerning the triggering of acute cardiovascular diseases has yielded a change in philosophical approach to this field. During the last decade, clinical evidence suggested that the term acute risk factors can be used for the activities and events that suddenly and transiently increase the risk of acute cardiac diseases. External triggers, such as heavy physical activity, emotional stress, eating, cold or heat exposure, coffee or alcohol consumption, cocaine or marijuana use and sexual intercourse are recognized as most important acute risk factors. It is likely that the morning hours may be considered as an endogenous, external triggering independent acute risk factor related to physiological sympathetic arousal. The features of triggering have been best described for an acute myocardial infarction whose moment of onset appears to be the result of a dynamic interaction between an endogenous response to acute risk factors and patient vulnerability. In this article, pathophysiological changes implicated as internal triggering mechanisms are summarized and the terms sympathetic and parasympathetic triggering patterns are introduced. A highly individual approach tailored both to protect against acute risk factors and to reduce patient vulnerability could provide a more complete protection from myocardial infarction and other coronary incidents. Lifestyle modifications, regular physical activity and adequate drug regimens may at least prove able to defer the occurrence of coronary thrombosis, thereby providing time for the development of collateral vessels, plaque stabilization or invasive/surgical treatment.

Mental stress-induced hemoconcentration and its recovery: A controlled study of time course and mechanisms

Hemoconcentration to mental stress has been implicated in acute cardiovascular events. Participants were exposed to a 30-min baseline, a 4-min stress task, and a 40-min recovery; they also undertook a 74-min no-stress control session. Hemodynamic activity was recorded and blood sampled regularly and analyzed for hematocrit, colloid osmotic pressure, and coagulation time. Hematocrit increased with stress and fully recovered after 20 min. Colloid osmotic pressure showed a similar time course. No such changes occurred in the control session. Coagulation time was not perturbed by stress. The pattern of increase in hematocrit correlated with contemporary colloid osmotic pressure and blood pressure. In recovery, only colloid osmotic pressure was strongly associated with hematocrit. The mechanisms of stress-induced hemoconcentration may differ from those responsible for recovery, which may depend primarily on colloid osmotic pressure.

The hazards of watching football — are Australians at risk?

OBJECTIVE

To review whether watching football increases the population cardiac event risk in New South Wales.

DESIGN

Analysis of hospital admissions for acute myocardial infarction, other cardiovascular disease, and other acute injuries at the time of two stressful sporting events in NSW in 2005: the Sydney Swans playing in the Australian Football League (AFL) Grand Final, and the Socceroos' penalty shoot-out in their World Cup qualifying match against Uruguay.

RESULTS

There were no increases in any of the studied admission events at the time of, or in the days immediately following, these football matches.

CONCLUSIONS

Australians appear to be resistant to acute stressors associated with watching sporting events, possibly due to higher rates of motivational deficiency disorder (MoDeD) than in European populations.

Mass community cycling events: who participates and is their behaviour influenced by participation?

BACKGROUND

Participation in mass physical activity events may be a novel approach for encouraging inactive or low active adults to trial an active behaviour. The public health applicability of this strategy has not been investigated thoroughly. The purpose of this study to was describe participants in a mass cycling event and examine the subsequent effect on cycling behaviour.

METHODS

A sample of men and women aged 16 years and older (n = 918) who registered online for a mass cycling event reported cycling ability and number of times they rode a bicycle during the month before the event. One month after the event participants completed an online follow-up questionnaire and reported cycling ability, lifestyle physical activity, and number of times they rode a bicycle during the month after the event. McNemar's test was used to examine changes in self-rated cycling ability, and repeated measures mixed linear modeling was used to determine whether average number of monthly bicycle rides changed between pre-event and post-event assessment.

RESULTS

Participants in the cycling event were predominantly male (72%), 83% rated themselves as competent or regular cyclists, and 68% rated themselves as more active than others of the same sex and age. Half of the survey respondents that rated their cycling ability as low before the event subsequently rated themselves as high one month after the event. Respondents with low pre-event self-rated cycling ability reported an average 4 sessions of bicycle riding the month before the event and an average 6.8 sessions of bicycle riding a month after the event. This increase in average sessions of bicycle riding was significant (p < .0001). Similarly, first-time participants in this particular cycling event significantly increased average sessions of cycling from 7.2 pre-event to 8.9 sessions one month after the event.

CONCLUSION

Participants who were novice riders or first time participants significantly increased their number of bicycle rides in the month after the event. Further knowledge about the public health applicability of mass events is needed, and methods for attracting less active and novice individuals to participate remain to be developed.

Time course and mechanisms of hemoconcentration in response to mental stress

Hemoconcentration with mental stress exposure may be involved in the triggering of acute cardiovascular events. In the present study, hematocrit was measured repeatedly at baseline, during a 4 min mental stress task and during 20 min of recovery. Blood was sampled every 1-2 min throughout. Blood pressure, heart rate and R-wave to pulse interval, a measure of cardiac contractility, were measured with the same periodicity. The stress task elicited a 1.3% increase in hematocrit, which was sustained with full return to baseline level occurring only after 16 min of recovery. Between-subject correlations between hematocrit and hemodynamic activity were low. Aggregate within-subject coefficients were more impressive; the temporal profile of hematocrit correlated significantly with all hemodynamic variables. Similar within-subject analyses indicated that whereas cardiac contractility was correlated with hematocrit both during stress-related increase and subsequent recovery, blood pressure was related to hematocrit only during the increase. This suggests that stress-induced hemoconcentration may driven by different mechanisms than those which underlie its recovery.

Stress, life events, and socioeconomic disparities in health: results from the Americans' Changing Lives Study

It has been hypothesized that exposure to stress and negative life events is related to poor health outcomes, and that differential exposure to stress plays a role in socioeconomic disparities in health. Data from three waves of the Americans' Changing Lives study (n = 3,617) were analyzed to investigate prospectively the relationship among socioeconomic indicators, five measures of stress/negative life events, and the health outcomes of mortality, functional limitations, and self-rated health. The results revealed that (1) life events and other types of stressors are clearly related to socioeconomic position; (2) a count of negative lifetime events was positively associated with mortality; (3) a higher score on a financial stress scale was predictive of severe/moderate functional limitations and fair/poor self-rated health at wave 3; and (4) a higher score on a parental stress scale was predictive of fair/poor self-rated health at wave 3. The negative effects of low income on functional limitations attenuated to insignificance when waves 1 and 2 stress/life event measures were controlled for, but other socioeconomic disparities in health change remained sizable and significant when adjusted for exposure to stressors. The results support the hypothesis that differential exposure to stress and negative life events is one of many ways in which socioeconomic inequalities in health are produced in society.

Behavioral and emotional triggers of acute coronary syndromes: a systematic review and critique

OBJECTIVE

The objective of this study was to review the evidence that behavioral and emotional factors are triggers of acute coronary syndromes.

METHOD

Systematic review of the published literature from 1970 to 2004 of trigger events, defined as stimuli or activities occurring within 24 hours of the onset of acute coronary syndromes.

RESULTS

There is consistent evidence that physical exertion (particularly by people who are not normally active), emotional stress, anger, and extreme excitement can trigger acute myocardial infarction and sudden cardiac death in susceptible individuals. Many triggers operate within 1 to 2 hours of symptom onset. There are methodologic limitations to the current literature, including sampling, retrospective reporting, and presentation biases, the role of memory decay and salience, and reverse causation because of silent prodromal events.

CONCLUSIONS

Behavioral and emotional factors are probable triggers of acute coronary syndromes in vulnerable individuals, and the pathophysiological processes elicited by these stimuli are being increasingly understood. The benefits to patients of knowledge to these processes have yet to accrue.

Increased C reactive protein in response to acute stress in patients with rheumatoid arthritis

OBJECTIVE

To assess the effects of acute stress on inflammatory, haemostatic, rheological, and haemodynamic activity in patients with rheumatoid arthritis (RA) in comparison with patients with osteoarthritis (OA).

METHODS

21 patients with RA and 10 with OA underwent a brief mental stress task while standing. Inflammatory, haemostatic, rheological, and haemodynamic variables were measured at baseline, during the task, and at recovery.

RESULTS

At baseline, erythrocyte sedimentation rate and fibrinogen were higher in RA than OA. White blood cell count, fibrinogen, blood pressure, and pulse rate increased, whereas prothrombin time and plasma volume decreased during the task in both patient groups. The stress task increased C reactive protein (CRP) only in patients with RA, and more specifically in those patients with RA with high disease activity.

CONCLUSIONS

The increase in the inflammatory marker CRP, which was specific to patients with RA, combined with the haemostatic, rheological, and haemodynamic reactions to the stress task, over and above the already high baseline levels, could underlie the increased risk for myocardial infarction in this vulnerable patient group.

Anger, Anxiety, and Depression as Risk Factors for Cardiovascular Disease: The Problems and Implications of Overlapping Affective Dispositions

Several recent reviews have identified 3 affective dispositions--depression, anxiety, and anger-hostility--as putative risk factors for coronary heart disease. There are, however, mixed and negative results. Following a critical summary of epidemiological findings, the present article discusses the construct and measurement overlap among the 3 negative affects. Recognition of the overlap necessitates the development of more complex affect-disease models and has implications for the interpretation of prior studies, statistical analyses, prevention, and intervention in health psychology and behavioral medicine. The overlap among the 3 negative dispositions also leaves open the possibility that a general disposition toward negative affectivity may be more important for disease risk than any specific negative affect.

The influence of hydration status on stress-induced hemoconcentration

This study examined the effects of hydration status on rheological and hemodynamic activity during rest, mental stress, postural stress, and combined mental/postural stress in 24 men when euhydrated and hyperhydrated. The stress tasks elicited hemoconcentration, although the effects were less pronounced during mental stress. Hyperhydration was associated with higher plasma volume throughout. All stress tasks also perturbed hemodynamic activity, irrespective of hydration status, with the exception of heart rate reactivity, which was attenuated when hyperhydrated. As expected the combined stress during euhydration was associated with an unfavorable rheological and cardiovascular profile, which may help explain the increased incidence of cardiovascular events in the morning.

Mental stress-induced hemoconcentration: Sex differences and mechanisms

Given the possible role of hemoconcentration in myocardial infarction and apparent sex differences in susceptibility, three studies examined sex differences in mental stress-induced hemoconcentration, and explored possible underlying mechanisms. Blood pressure, heart rate, and hematocrit were monitored at rest and in response to a mental stress task that was contrived to be increasingly provocative across the three studies. This was confirmed by self-report, performance, and cardiovascular reactivity data. The most convincing evidence for hemoconcentration effects and sex differences in hemoconcentration emerged from exposure to the more provocative of the stress tasks, with men also showing greater hemoconcentration than women. Blood pressure reactivity was a strong and consistent predictor of stress-induced hemoconcentration. These findings may help to explain sex differences in susceptibility to myocardial infarction.