Chiari network: An interesting transesophageal echocardiographic finding

Chiari Network: An Interesting Transesophageal Eehocardiographie Finding To the Editor Clements et al, 1 in their article "Coronary Sinus Catheterization Made Easy for Port-Access Minimally Invasive Cardiac Surgery," mentioned the presence of valves (fibrous bands) at the opening of the coronary sinus that can make the coronary sinus catheterization difficult. In reference to this article, we want to mention the presence of the Chiari network (Figs 1 and 2), which is shown on transesophageal echocardiography. An anesthesiologist not familiar with this may misinterpret it as a right atrium (RA) mass, clot, or Eustachian valve. The Chiari network 2,3 is seen as a perforated flagellar structure with undulating irregular motion in the RA. It is supposed to be the degenerated remnant of a valve of the coronary sinus. It may be large with a chaotic movement and may be confused with an RA mass. 4 An important differential diagnosis is the Eustachian valve, 5 which is developmentally a venous valve at the junction of the inferior vena cava (IVC) and RA. It directs the oxygenated blood from the IVC toward the atrial septum and left atrium during fetal circulation. It may persist in adults as a membrane near the opening of the IVC, showing undulating motion, and it may be so prominent as to obstruct IVC flow. The presence of the Chiari network, Eustachian valve, and RA masses may lead to problems in the insertion of a retrograde coronary sinus catheter during Port-Access surgery.

Fig1. Multiplane transesophagsel echocardiographic image (modified bicaval view) of the right atrium (RA) showing the inferior vena cava (IVC) and coronary sinus opening on the left and superior vena cava (SVC) on the right. A filamentous structure (two arrows) is seen between the coronary sinus and IVC opening. Abbreviation: PAC, pulmonary artery catheter.

Fig2. Multiplane transesophagsel echocardiographic image showing the short-axis view of the heart at the level of great vessels. The inferior vena cava (IVC) is opening into the right atrium (RA). A filamentous structure (two arrows) is present at its base (Chlari network). Abbreviations: AO, aorta; RVOT, right ventricular outflow tract; TV, tricuspid valve; PAC, pulmonary artery catheter.

Sanjay Mittal, MD Milind Bhise, MD Yatin Mehta, MD, DNB, FRCA Naresh Trehan, MD Department of Anesthesia and Cardiology Escorts Heart Institute and Research Centre New Delhi, India

REFERENCES

1. Clements F, Wright SJ, de Bruijn N: Coronary sinus catheterization made easy for Port-Access minimally invasive cardiac surgery. J Cardiothorac Vasc Anesth 12:96-100, 1998 2. Wemer JA, Cheitlin MD, Gross BW, et al: Echocardiographic appearance of the Chiari network: Differentiation from fight heart pathology. Circulation 63:1104-1109, 1981 3. Cujec B, Mycyk T, Khouri M: Identification of Chiari's network

with transesophageal echocardiography. J Am Soc Echocardiogr 5:9699, 1992 4. Katz ES, Freedberg RS, Rutkovsky L, et al: Identification of an unusual fight atrial mass as a Chiari network by biplane transesophageal echocardiography. Echocardiography 9:273-275, 1992 5. Schrem SS, Freedberg RS, Gindea AJ, Kronzon I: The association between usually large Eustachian valves and atrioventricular valvular prolapse. Am Heart J 120:204-206, 1990

Journal of Cardiothoracic and Vascular Anesthesia, Vo113, No 2 (April), 1999: pp 243-245

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