Chiari network

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]

The Chiari network is a filamentous structure seen in the right atrium.

History

The Chiari network was first described in 1897 in an autopsy series by Dr Chiari.

Prevalence

The Chiari network was noted to be present in 2-3% of the population. It was detected in approximately 1.5% of transthoracic echocardiographic studies in a series in 1984. Technical improvements in image quality may have increased the incidence of its detection.

Pathophysiology

The Chiari network is an embryological remnant of one of the valves of sinus venosus. This embryonic remnant has no known purpose and is not pathological. Although the Chiari network has no clinical significance, it must be distinguished from other pathological masses in the right atrium including thrombus, vegetation, and myxoma.

The Chiari network appears to be a web-like structure with a variable number of thread-like components.

Chiari network is characterized by whip-like motion within the right atrium and attachment to the wall of the right atrium in close proximity to the entrance of the inferior vena cava.

Diagnosis

Entrapment of catheters during right heart catheterization has been reported.

Echocardiography

Autopsy Findings

Images courtesy of Professor Peter Anderson DVM PhD and published with permission © PEIR, University of Alabama at Birmingham, Department of Pathology

Chiari Network: Gross; fixed tissue, close-up of coronary sinus with fenestrae in valve
Chiari Network: Gross; fixed tissue, close-up view, an excellent example

Additional Resources

JA Werner, MD Cheitlin, BW Gross, SM Speck and TD Ivey. Echocardiographic appearance of the Chiari network: differentiation from right-heart pathology. Circulation 1981, Vol 63, 1104-1109,
H. Tanaka, K. Ueda, M. Murakami, S. Hasegawa, and M. Sunamori A prominent Chiari network Ann. Thorac. Surg., June 1, 2002; 73(6): 1985 – 1985.
D. M. Payne, R. J. F. Baskett, and G. M. Hirsch Infectious endocarditis of a Chiari network Ann. Thorac. Surg., October 1, 2003; 76(4): 1303 – 1305.
H. Hara, R. Virmani, E. Ladich, S. Mackey-Bojack, J. Titus, M. Reisman, W. Gray, M. Nakamura, M. Mooney, A. Poulose, et al. Patent Foramen Ovale: Current Pathology, Pathophysiology, and Clinical Status J. Am. Coll. Cardiol., November 1, 2005; 46(9): 1768 – 1776.

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