To the Editor
I have read the article entitled “Predictors of new-onset atrial fibrillation in elderly patients with coronary artery disease after coronary artery bypass graft” by Anatoĺevna, et al.[1] with great interest. The investigators reported that independent predictors of postoperative atrial fibrillation (POAF) after coronary artery bypass graft (CABG) in elderly patients were left atrium dimension (LA) and the increased postoperative concentration of Interleukin (IL)-6, IL-8 and superoxide dismutase.[1]
Development of atrial fibrillation (AF) after cardiac surgery is associated with increased morbidity, mortality, longer hospital stay and it is associated with a twofold to threefold increase in postoperative stroke. Older age, obesity, hypertension, prior AF and congestive heart failure associated with higher risk of developing AF after cardiac surgery.[2]
Vitamin D is transformed in the liver and kidney to calcidiol and calcitriol, respectively, and effects specific target tissues via vitamin D receptors (VDR). VDR are found in other tissues, including the brain, cardiomyocytes, vascular smooth muscle cells, endothelial cells, pancreatic beta-cells, skeletal muscle, prostate, colon, macrophages.[3]
There was a strong relationship between vitamin D deficiency and AF. The role of vitamin D deficiency in the onset of AF was suggested because of several potential mechanisms described previously. Vitamin D regulates inflammatory responses and up-regulates the expression of anti-inflammatory cytokines such as IL-10 according to in-vitro experiments.[4] Also, vitamin D regulates renin-angiotensin-aldosterone system (RAAS) activity. Activated RAAS can lead to oxidative stress and inflammation, both of which can culminate in AF. It is assumed that tissue angiotensin II can induce apoptosis of cardiomyocytes and can contribute to changes in atrial structure.[5]
In the light of these knowledges, patients' vitamin D level should be mentioned, and also discussed relationship between vitamin D level and POAF.
References
- 1.Anatoĺevna RO, Veniaminovich FO, Mikhaylovich KS. Predictors of new-onset atrial fibrillation in elderly patients with coronary artery disease after coronary artery bypass graft. J Geriatr Cardiol. 2016;13:444–449. doi: 10.11909/j.issn.1671-5411.2016.05.017. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Amar D, Shi W, Hogue CW, et al. Clinical prediction rule for atrial fibrillation after coronary artery bypass grafting. J Am Coll Cardiol. 2004;44:1248–1253. doi: 10.1016/j.jacc.2004.05.078. [DOI] [PubMed] [Google Scholar]
- 3.Dusso AS, Brown AJ, Slatopolsky E, Vitamin D. Am J Physiol Renal Physiol. 2005;289:8–28. doi: 10.1152/ajprenal.00336.2004. [DOI] [PubMed] [Google Scholar]
- 4.Canning MO, Grotenhuis K, de Wit H, et al. 1-alpha,25-Dihydroxyvitamin D3 (1,25(OH)(2)D(3)) hampers the maturation of fully active immature dendritic cells from monocytes. Eur J Endocrinol. 2001;145:351–357. doi: 10.1530/eje.0.1450351. [DOI] [PubMed] [Google Scholar]
- 5.Frustaci A, Chimenti C, Bellocci F, et al. Histological substrate of atrial biopsies in patients with lone atrial fibrillation. Circulation. 1997;96:1180–1184. doi: 10.1161/01.cir.96.4.1180. [DOI] [PubMed] [Google Scholar]