Citation, DOI and article data
Prevalence estimates for the general population vary widely, ranging from 2% - 10% of randomly selected, asymptomatic patients 2.
While thought to be of no innate clinical significance, the presence of a Chiari network is associated with the following 3:
- tricuspid regurgitation
- infectious endocarditis
- embolic transient ischemic attack and/or stroke
- requires presence of patent foramen ovale
Resorption of the right valve of the embryologic sinus venosus occurs during the normal development of the right atrium, forming the Eustachian valve and the crista terminalis. Incomplete resorption, however, may result in either the persistence of a prominent Eustachian valve or a Chiari network, which shares the same point of anatomical attachment but differs in appearance.
A Chiari network may be visualized with both transthoracic (TTE) or transesophageal (TEE) approaches, most often an incidental finding when the former is utilized to investigate an unrelated pathology.
Multiple transthoracic windows and views should be used to adequately assess the right atrium, including the apical 4 chamber view, parasternal right ventricular inflow tract view, and a basally angulated parasternal short axis view. The following grey scale features are characteristic of a Chiari network;
- reticulated network of hyperechoic membranous structures located within the right atrium
- freely mobile throughout systole and diastole
- most often tethered to the orifice of the inferior vena cava, around which it may appear to rotate 1
Chiari network can sometimes be seen as a lacelike filling defect but can be challenging due to heterogeneity of contrast enhancement within the right atrium. Identification of its attachment to the inferior vena cava ostium can aid establish a diagnosis.
History and etymology
Originally described in 1897 by the Austrian pathologist Dr. Hans Chiari (1851-1916) 4.
- 1. Werner JA, Cheitlin MD, Gross BW, Speck SM, Ivey TD. Echocardiographic appearance of the Chiari network: differentiation from right-heart pathology. (1981) Circulation. 63 (5): 1104-9. Pubmed
- 2. Schwimmer-Okike N, Niebuhr J, Schramek GG, Frantz S, Kielstein H. The Presence of a Large Chiari Network in a Patient with Atrial Fibrillation and Stroke. (2016) Case reports in cardiology. 2016: 4839315. doi:10.1155/2016/4839315 - Pubmed
- 3. Fredericks P, Liu T, Colla J. Right Atrial Thrombus or Chiari Network?. (2017) Clinical practice and cases in emergency medicine. 1 (3): 258-259. doi:10.5811/cpcem.2017.2.32820 - Pubmed
- 4. Tubbs RS, Cohen-Gadol AA. Hans Chiari (1851-1916). (2010) Journal of neurology. 257 (7): 1218-20. doi:10.1007/s00415-010-5529-0 - Pubmed
- 5. Scott D Solomon, Justina Wu, Linda D. Gillam. Essential Echocardiography: A Companion to Braunwald’s Heart Disease E-Book. (2017) ISBN: 9780323508728
- 6. Prabhakar Rajiah, James MacNamara, Abhishek Chaturvedi, Ravi Ashwath, Nicholas L. Fulton, Harold Goerne. Bands in the Heart: Multimodality Imaging Review. (2019) RadioGraphics. 39 (5): 1238-1263. doi:10.1148/rg.2019180176 - Pubmed