Echocardiography is a good tool to detect individuals with high risk of atrial fibrillation and stroke, according to the results of Sweta Tiwari‘s PhD thesis.


  1. Enlarged left atrium measured by echocardiography associates with a fourfold increased risk of atrial fibrillation.
  2. Persons with a large left atrium and at least one risk factor for stroke have nine times higher stroke risk.
  3. Individuals with atrial fibrillation, but without stroke, have increased cognitive decline.


Thesis: Atrial Fibrillation: A prospective population study of risk factors and complications. The Tromsø Study
Candidate: Sweta Tiwari
Time: April 26, 2018 at 12:15
Place: UiT The Arctic University of Norway: MH-building, Auditorium 7
Link to university website (in Norwegian)


(1) Both women and men with a severely enlarged left atrium have fourfold increased risk of atrial fibrillation. The association is independent of established risk factors. A moderately enlarged left atrium is associated with 60 % increased risk.

The study followed 2406 participants from the Tromsø Study from 1994 to 2010. 193 women og 269 men had confirmed atrial fibrillation during follow-up.

(2) Enlarged size of the left atrium combined with one or more established risk factors for stroke can identify individuals with high risk of stroke. The model is at least as good for people without diagnosed atrial fibrillation as it is for people with the diagnosis.

Those who had at least one of the risk factor in the CHA2DS2-VASc model, had four times higher risk of stroke during follow-up compared to those who had no risk factors. In those who also had severely enlarged left atrium, the risk was increased more than ninefold. 2884 men and women were included in the study, and 325 of them had a stroke during 18 years of follow-up.

(3) Atrial fibrillation is independently associated with cognitive decline as measured with the tapping test. The study includes analyses from 2491 stroke-free persons who performed three cognitive tests in the two Tromsø studies in 2001 and 2007/2008. The two other cognitive tests, however, did not show increased cognitive decline in those with atrial fibrillation compared to those without atrial fibrillation.


(1) Tiwari, S., Schirmer, H., Jacobsen, B. K., Hopstock, L. A., Nyrnes, A., Heggelund, G., Njølstad, I., Mathiesen, E. B., & Løchen, M. L. (2015). Association between diastolic dysfunction and future atrial fibrillation in the Tromsø Study from 1994 to 2010Heart101(16), 1302-1308.

(2) Tiwari, S., Løchen, M. L., Jacobsen, B. K., Hopstock, L. A., Nyrnes, A., Njølstad, I., Mathiesen, E. B., & Schirmer, H. (2016). CHA2DS2-VASc score, left atrial size and atrial fibrillation as stroke risk factors in the Tromsø StudyOpen heart3(2), e000439.

(3) Tiwari, S., Løchen, M. L., Jacobsen, B. K., Hopstock, L. A., Nyrnes, A., Njølstad, I., Mathiesen, E. B., Arntzen, K. A., Ball, J. E., Stewart, S., Wilsgaard, T., & Schirmer, H. (2017). Atrial fibrillation is associated with cognitive decline in stroke‐free subjects: the Tromsø StudyEuropean journal of neurology24(12), 1485-1492.

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