Echocardiographic appearance of the Chiari network: differentiation from right-heart pathology.

Abstract

SUMMARY As echocardiography is being used more often, its value and accuracy are becoming more fully appreciated. Coincident with wider application of this imaging technique is the potential for identifying normal anatomic variants and their possible erroneous interpretation as pathologic states. In this report we describe the M-mode and two-dimensional echocardiographic features of a congenital remnant known as the Chiari network. This structure can present as a highly mobile, highly reflectant echo target that can be seen in several locations in the right atrium. We report here an index case that could be well examined echocardiographically and that was a cause of considerable concern due to the presence of congestive heart failure and a history of staphylococcal endocarditis. The presence of the Chiari network was confirmed pathologically. Subsequently, we found similar echocardiographic findings in 19 of 1248 patients (1.5%) studied in our laboratory. This congenital remnant, which is found pathologically in 2-3% of normal hearts, could be confused with valve disruption, vegetation or other mass lesion, particularly when associated with a suggestive clinical situation.M-MODE and two-dimensional echocardiography have gained wide acceptance for providing safe, repeatable and accurate diagnostic information in a variety of complicated clinical situations. Suspicion of valvular heart disease, particularly infection of the valves, represents an important indication for echocardiographic examination.1 2 Increasing experience with these techniques has allowed a better, and in some cases new, appreciation of normal and abnormal cardiac anatomy, motion and structural relationships.3 These include structures often described at cardiac surgery or at postmortem examination, but not previously demonstrable in ambulatory patients. We describe the echocardiographic appearance of the Chiari network, a not uncommon anatomic finding that might be considered a "normal variant."4 This structure, particularly in the setting of fever, congestive heart failure, pulmonary infiltrates and a history of i.v. drug abuse, could be mistaken for evidence of active infection or disruption of normal right-sided structures, possibly requiring urgent cardiac surgery. Materials

Prolapse of posterior leaflet of tricuspid valve presenting as an undulating artifact in right atrium: A rare case report

“…Commonest differential diagnosis in the present case is a Chiari network [2,3] (a fenestrated remnant of right valve of sinus venosus resulting from incomplete regression during embryogenesis). Other differentials diagnosis for such a curvilinear, highly mobile, cyclically recurring echo mass include; vegetation on tricuspid valve, ruptured chordae tendineae to the tricuspid apparatus, a small right-atrium thrombus or a pedunculated right-heart tumor.…”

Chiari Network in Right Atrium of Heart

“…In order to make definite diagnosis and differentiate from other structures real time three dimensional TTE (3D-TTE) and cardiac magnetic r e s o n a n c e i m a g i n g ( M R I ) a r e complimentary 2,4 The Chiari network is mostly benign without any clinical significance but it has high association with patent foramen ovale (PFO) and atrio-septal aneurysm (ASA) facilitating paradoxical embolism (embolic stroke). 2,5 It has to be differentiated from other right atrial normal structures like Eustachian and Thebesian valves and abnormalities such as right atrial thrombi, tumors, vegetations, cor triatriatum dexter, Ebstein anomaly of the tricuspid valve or tricuspid-chordal rupture. 6 There are reports of its association with atrial fibrillation, supraventricular arrhythmias, t r i c u s p i d r e g u rg i t a t i o n a n d i n f e c t i v e endocarditis.…”

The Prevalence of Eustachian Valve on Transoesophageal Echo Examination

“…A Eustachian valve, or valve of the inferior vena cava, was found to be present in some form in all but seventeen of these hearts" -86% (ref 2 ). The echocardiographic features of Chiari network were described in 1981 (ref 3 ). Identification of the Eustachian valve is not a major issue in most echocardiographic studies.…”