Physical Activity and Anger or Emotional Upset as Triggers of Acute Myocardial Infarction: The INTERHEART Study

Smyth A, O’Donnell M, Lamelas P, et al; on behalf of the INTERHEART Investigators.

Circulation2016;134:1059-1067.

Background

According to the INTERHEART study, >90% of the myocardial infarction (MI) risk is associated with long-term exposure to 9 risk factors [1]. According to local observational studies with small sample sizes, physical exertion and anger or emotional upset may trigger an acute MI (AMI) [2,3].
In this analysis of the INTERHEART study (a case-control study), the association of physical activity and anger or emotional upset with AMI was assessed in a large, international population in 52 countries. Hereto, 12461 consecutive cases with first AMI (defined by characteristic symptoms and ischemic ECG changes) were recruited. Only the cases of AMI were analysed, because only for them, and not for the age- and sex-matched controls exposure to potential triggers was collected systematically. By means of a structured questionnaire patients were asked dichotomous questions on physical exertion and emotional state in the hour before the onset of symptoms, and during the same hour on the previous days.

Main results

• Compared with the control period, the adjusted odds of AMI associated with physical exertion occurring in the 1 hour before AMI symptom onset was 2.31 (99%CI: 1.96–2.72) with a risk of 7.7% (99%CI: 6.3–8.8).
• Compared with the control period, the adjusted odds anger or emotional upset occurring during the case period was 2.44 (99% CI: 2.06–2.89) with a risk of 8.5% (99% CI: 7.0–9.6).
• Compared with exposure to neither trigger during the control period, the adjusted odds of AMI associated with exposure to both physical exertion and anger or emotional upset occurring during the case period was 3.05 (99% CI: 2.29–4.07; P for interaction <0.001).
• There was no statistically significant effect modification for physical exertion or anger or emotional upset in analyses stratified by CV prevention medications before AMI, including aspirin, β-blockers, ACE inhibitors, and cholesterol-lowering therapy.
• There was no effect modification by geographical region for either trigger. The conditional relationship between physical exertion and AMI was consistent by time of onset (P for homogeneity=0.08) and day of onset (P for homogeneity=0.95). Similarly, the conditional relationship between anger or emotional upset and AMI was consistent by time of onset (P for homogeneity= 0.17) and day of onset (P for homogeneity=0.99).
• The odds of AMI occurring with either trigger tended to be highest between 6 pm and midnight and lowest between midnight and 6 am.

Conclusion

Physical exertion and anger or emotional upset were common in the 1 hour before the onset of symptoms of AMI. The greatest magnitude of association was seen in those with both triggers and it was independent of geographical region and CV medications. These findings support the clinical practice of advising patients to minimise exposure to extremes of anger or emotional upset or vigorous physical exertion (but not any physical activity).

Find this article online at Circulation

References

1. Yusuf S, Hawken S, Ounpuu S, et al; INTERHEART Study Investigators. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet. 2004;364:937–952.
2. Culić V, Eterović D, Mirić D. Meta-analysis of possible external triggers of acute myocardial infarction. Int J Cardiol. 2005;99:1–8.
3. Nawrot TS, Perez L, Künzli N, et al. Public health importance of triggers of myocardial infarction: a comparative risk assessment. Lancet. 2011;377:732–740.