Day-of-the-week variations in myocardial infarction onset over a 27-year period: the importance of age and other risk factors

Potential Role of Life Stress in Unexplained Sudden Cardiac Arrest

Background

The etiology of sudden cardiac arrest (SCA) in individuals without known cardiovascular heart disease remains elusive in nearly half of all patients after systematic testing. We investigated the relationship between stressful life events and SCA risk in cases of explained and unexplained SCA (USCA) events.

Methods

Individuals who previously experienced SCA were enrolled prospectively and divided into a USCA or explained SCA (ESCA) subgroup dependent on whether a diagnosis was ascribed after SCA. Participants completed either the 1997 Recent Life Changes Questionnaire, Student Stress Scale, or Social Re-adjustment Rating Scale for Non-Adults recalling events during the year preceding their SCA, depending on age at SCA presentation; all measure stress in life change units (LCUs). SCA group scores were compared with an age- and sex-matched control group.

Results

We compared 36 SCA group participants (22 USCA, 14 ESCA, age 47 ± 15 years, age at SCA 40 ± 14 years, 50% male) with 36 control participants (age 47 ± 15 years, 50% male). There was no significant difference in LCU score between the control group and the SCA group (248 ± 181 LCU vs 252 ± 227 LCU; P > .05). The ESCA subgroup had significantly lower mean LCU scores than the USCA subgroup (163 ± 183 LCU vs 308 ± 237 LCU; P = .030).

Conclusions

Stressful life events, especially those producing chronic stress, might predispose otherwise healthy individuals to lethal arrhythmias. Further investigation into the role of stress in SCA precipitation is warranted.

Asian dust exposure triggers acute myocardial infarction

Aims

To elucidate whether Asian dust is associated with the incidence of acute myocardial infarction (AMI) and to clarify whether patients who are highly sensitive to Asian dust will develop AMI.

Methods and results

Twenty-one participating institutions located throughout Kumamoto Prefecture and capable of performing coronary intervention were included in the study. Data for ground-level observations of Asian dust events were measured at the Kumamoto Local Meteorological Observatory. Data collected between 1 April 2010 and 31 March 2015 were analysed, and 3713 consecutive AMI patients were included. A time-stratified case-crossover design was applied to examine the association between Asian dust exposure and AMI. The occurrence of Asian dust events at 1 day before the onset of AMI was associated with the incidence of AMI [odds ratio (OR), 1.46; 95% confidence interval (CI), 1.09-1.95] and especially, non-ST-segment elevation myocardial infarction was significant (OR 2.03; 95% CI, 1.30-3.15). A significant association between AMI and Asian dust was observed in patients with age ≥75 years, male sex, hypertension, diabetes mellitus, never-smoking status, and chronic kidney disease (CKD). However, Asian dust events had a great impact on AMI onset in patients with CKD (P < 0.01). A scoring system accounting for several AMI risk factors was developed. The occurrence of Asian dust events was found to be significantly associated with AMI incidence among patients with a risk score of 5-6 (OR 2.45; 95% CI: 1.14-5.27).

Conclusion

Asian dust events may lead to AMI and have a great impact on its onset in patients with CKD.

Does acute myocardial infarction kill more people on weekends? Analysis of in-hospital mortality rates for weekend admissions in Portugal

Objectives To investigate a possible weekend effect in the in-hospital mortality rate for acute myocardial infarction in Portugal, and whether the delay in invasive intervention contributes to this effect. Methods Data from the National 2011-2015 Diagnostic-Related-Group databases were analysed. The focus was on adult patients admitted via the emergency department and with the primary diagnosis of acute myocardial infarction. Patients were grouped according to ST-elevation myocardial infarction and non-ST-elevation myocardial infarction episodes. We employed multivariable logistic regressions to determine the association between weekend admission and in-hospital mortality, controlling for episode complexity (through a severity index and acute comorbidities), demographic characteristics and hospital identifications. The association between the probability of a prompt surgery (within one day) and the day of admission was investigated to explore the possible delay of care delivery for patients admitted during weekends. Results Our results indicate that in-hospital mortality rates were not significantly higher for weekend admissions than for weekday admissions in both ST-elevation myocardial infarction (STEMI) and non-STEMI episodes. This result is robust to the inclusion of a number of potential confounding mechanisms. Patients admitted on weekends had lower probabilities of undergoing invasive cardiac surgery within the day after admission, but delay in care delivery during the weekend was not associated with worse outcomes in terms of in-hospital mortality. Conclusions There is no evidence for the existence of a weekend effect due to admission for acute myocardial infarction in Portugal, in both STEMI and non-STEMI episodes.

Temporal changes in myocardial infarction incidence rates are associated with periods of perceived psychosocial stress: A SWEDEHEART national registry study

BACKGROUND

Psychosocial stress might trigger myocardial infarction (MI). Increased MI incidence coincides with recurrent time periods during the year perceived as particularly stressful in the population.

METHODS

A stress-triggering hypothesis on the risk of MI onset was investigated with Swedish population data on MI hospital admission date and symptom onset date (N=156,690; 148,176) as registered from 2006 through 2013 in the national quality registry database Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies (SWEDEHEART). Poisson regression was applied to analyze daily MI rates during days belonging to the Christmas and New Year holidays, turns of the month, Mondays, weekends, and summer vacation in July compared with remaining control days.

RESULTS

Adjusted incidence rate ratios (IRRs) for MI rates were higher during Christmas and New Year holidays (IRR=1.07 [1.04-1.09], P<.001) and on Mondays (IRR=1.11 [1.09-1.13], P<.001) and lower in July (IRR=0.92 [0.90-0.94], P<.001) and over weekends (IRR=0.88 [0.87-0.89], P<.001), yet not during the turns of the month (IRR=1.01 [1.00-1.02], P=.891). These findings were also predominantly robust with symptom onset as alternative outcome, when adjusting for both established and some suggested-but-untested confounders, and in 8 subgroups.

CONCLUSIONS

Fluctuations in daily MI incidence rates are systematically related to time periods of presumed psychosocial stress. Further research might clarify mechanisms that are amenable to clinical alteration.

Chronobiology of Takotsubo Syndrome and Myocardial Infarction: Analogies and Differences

Several pathophysiologic factors, not harmful if taken alone, are capable of triggering unfavorable events when presenting together within the same temporal window (chronorisk), and the occurrence of many cardiovascular events is not evenly distributed in time. Both acute myocardial infarction and takotsubo syndrome seem to exhibit a temporal preference in their onset, characterized by variations according to time of day, day of the week, and month of the year, although with both analogies and differences.

Short-term effects of air pollution on hospitalization for acute myocardial infarction: age effect on lag pattern

The aim of the present study is to analyse the age effect on the lag patterns of relative risk of hospitalization for acute myocardial infarction and NO₂, PM₁₀ and O₃. Daily hospitalizations for AMI during the period 2008-2011 were extracted from administrative data. Analyses were performed using the quasi-Poisson regression model adjusted for seasonality, long-term trend, day of the week and temperature. We observed very different patterns depending on age. For NO₂ and PM₁₀, the younger group (25-54 years) shows a more delayed effect in comparison with the two older age groups (55-64 and ≥ 65 years). Overall, the associations between NO₂ and AMI are higher compared to PM₁₀. There are no associations between O₃ and AMI. This study indicates that age plays a major role in the lag pattern. Younger people have delayed effects, but they are nevertheless sensitive to air pollution.