In her PhD thesis, Andrea Milde Øhrn has found several differences between clinically recoginzed and unrecognized myocardial infarction.

MAIN RESULTS:

1. Pain tolerance is higher in persons with silent myocardial infarction than in those with known myocardial infarction.
2. Unrecognized myocardial infarction does not improve cardiovascular risk prediction beyond traditional risk factors.
3. Silent myocardial infarction is more associated with small vessel disease.

THESIS DEFENCE:

Thesis: Unrecognized Myocardial Infarction. Pain tolerance, prognosis and pathogenesis in men and women
Candidate: Andrea Milde Øhrn
Time: March 22, 2018 at 12:15
Place: UiT The Arctic University of Norway, the MH building: Large auditorium
Link to university website (in Norwegian)

SUMMARY:

(1) Persons who have a heart attack without noticing have higher tolerance of pain compared to heart attack patients who experience chest pain. 387 of the 4 849 participants in the study had a previously unrecognized myocardial infarction, and they performed better at a pain test

Diabetes, hypertension, depression, anxiety, physical activity and smoking can be related to both pain tolerance and risk of silent myocardial infarction, but the association remained borderline statistically significant even after adjustment for all these variables. The associating between pain tolerance and silent infarction seemed to be strongest in women.

(2) A previously unrecoginzed myocardial infarction does not in itself seem to increase the risk of early death or a new cardiovascular event. Persons with silent infarctions do have higher risk compared to those who never had a heart attack, but the increased risk could be explained by differences in traditional risk factors between the two groups.

The study includes information from more than 5000 participants in the Tromsø Study.

(3) Silent myocardial infarctions more often seems to affect small coronary vessels and less often large vessels, when compared to a known infarction. Thus, the pathophysiology of an unrecognized myocardial infarction might differ from known infarctions.

REFERENCES:

(1) Øhrn, A. M., Nielsen, C. S., Schirmer, H., Stubhaug, A., Wilsgaard, T., & Lindekleiv, H. (2016). Pain Tolerance in Persons With Recognized and Unrecognized Myocardial Infarction: A Population‐Based, Cross‐Sectional Study. Journal of the American Heart Association, 5(12), e003846.

(2) Øhrn, A. M., Schirmer, H., Njølstad, I., Mathiesen, E. B., Eggen, A. E., Løchen, M. L., Wilsgaard, T., & Lindekleiv, H. (2018). Electrocardiographic unrecognized myocardial infarction does not improve prediction of cardiovascular events beyond traditional risk factors. The Tromsø Study. European journal of preventive cardiology, 25(1), 78-86.

(3) Øhrn, A. M., Schirmer, H., von Hanno, T., Mathiesen, E. B., Arntzen, K. A., Bertelsen, G., Njølstad, I., Løchen, M.-L., Wilsgaard, T., Merz, N. B., & Lindekleiv, H. (2018). Small and large vessel disease in persons with unrecognized compared to recognized myocardial infarction: The Tromsø Study 2007–2008. International journal of cardiology, 253, 14-19.