Prominent Chiari Network Research Articles

Chiari Network: Cause of an Unusual Difficulty during Atrial Septal Defect Device Closure

We report an unusual difficulty in unscrewing and releasing the atrial septal defect device during device closure because of the entrapment of the delivery cable in the prominent Chiari network. We suggest careful pre- and intra-procedure transesophageal guidance in recognizing and managing this rare challenge.

Utility of intracardiac echocardiography during ablation of atrial premature depolarizations with a prominent Chiari network

Utility of intracardiac echocardiography during ablation of atrial premature depolarizations with a prominent Chiari network

Giant Chiari Network, Foramen Ovale, and Paradoxical Embolism

A Chiari network is identified in the course of 1.3% to 4% of all autopsies and in 2% of patients who undergo transesophageal echocardiography. This network is associated with patent foramen ovale (PFO) in up to 80% of cases. Moreover, a number of scientific articles have linked this association to the development of stroke. The patient, a 78-year-old man with a history of embolic stroke and no evidence of cerebrovascular disease, complained of progressive breathlessness and dyspnea even on minimal exertion (New York Heart Association class III). A transesophageal echocardiogram revealed severe degenerative mitral regurgitation, severe functional tricuspid regurgitation, and a prominent Chiari network, in the shape of an inverted conewith a cul-de-sac (Figure A, white arrow), the distal end of which reached the PFO (Figure B, white arrowheads). We also observed turbulent flow from the left atrium to the right atrium through the PFO (Figure B, white arrow). The patient underwent mitral valve replacement, tricuspid valve repair, and PFO closure by means of simple suture with cardiopulmonary bypass. In the right atrium, we observed a large Chiari network (6.2 cm 6 cm), which we resected completely (Figures C and D, black arrow. TV, tricuspid valve). Although this malformation is uncommon, the characteristics of the Chiari network described here might explain the pathophysiology of a paradoxical embolism. The cul-de-sac would promote blood stasis and thrombosis, the inverted cone morphology would enable the mobilization of the thrombus toward the fenestrated region (Figure D, arrow), and the proximity of this region to the PFO could explain the embolism, especially during atrial diastole and Valsalva maneuvers. TV B A

Two-and three-dimensional echocardiographic views of a prominent Chiari network prolapsing into right ventricle

Two-and three-dimensional echocardiographic views of a prominent Chiari network prolapsing into right ventricle

Resolution of atrial thrombosis with heparin in a newborn with atrial flutter

Atrial thrombosis is a relatively rare event in children. We report a case of a newborn with AFI who after restoration of sinus rhythm, developed atrial thrombus on a prominent Chiari network floating between the right and left atrium through the patent foramen ovale. The thrombus was resolved following treatment with heparin without events. Atrial stunning was proposed as a key mechanistic phenomenon because the thrombus occurred after the cardioversion of AFI to sinus rhythm. Heparin may be effective in the resolution of atrial thrombus within a few days.

Pulmonary embolism, right ventricular strain, and intracardiac thrombus-in-transit: Evaluation using comprehensive cardiothoracic computed tomography

A 67-year-old woman presented with symptoms of exertional chest discomfort and dyspnea that had been progressive over the past few days. Her initial evaluation was significant of a mildly elevated troponin-T level and T-wave inversion in leads V(1)-V(2) on an electrocardiogram (ECG). Initial suspicion was for acute coronary syndrome. However, a transthoracic echocardiogram showed normal left ventricular systolic function, moderate right ventricular enlargement with moderate decrease in systolic function, possible left atrial mass or thrombus, and a possible right atrial mass or thrombus versus a prominent Chiari network. ECG-gated comprehensive cardiothoracic computed tomography (CT) with a 64-slice multidetector CT was done to assess for pulmonary embolism or acute coronary syndrome and to further evaluate the possible right and left atrial masses. This showed large bilateral pulmonary embolism, interatrial thrombus in transit through a patent foramen ovale, and minimal coronary atherosclerosis. Dynamic imaging showed right ventricular enlargement with severe systolic dysfunction. The patient underwent successful pulmonary thromboembolectomy, removal of intracardiac thrombus, and closure of patent foramen ovale.

Three-dimensional Imaging of Redundant Chiari’s Network Prolapsing into Right Ventricle

An asymptomatic 1-month-old girl was studied in another institution because of the presence of a cardiac murmur, and referred to our center for further evaluation as a result of tricuspid valve abnormalities detected in the echocardiographic study. Echocardiography revealed a very redundant, thin, freely mobile structure in the right atrium, moving rapidly in (systole) and out (diastole) of the right ventricle through the tricuspid orifice. It arose from near the border of the inferior vena cava and attached to the atrial wall close to the coronary sinus ostium, suggesting an unusually prominent Chiari's network. Three-dimensional imaging allowed definition of the structure in all the planes and dimensions, and the relationship of the structure with right atrium and ventricle. Chiari's network is an embryonic remnant present in 2% to 3% of the population. The identification of a Chiari's network is important because the widely mobile structure within the right atrium can be confused with other entities, such as right heart vegetation, flail tricuspid leaflet, ruptured chordae tendinae, or a thrombus.

Chiari Network Entanglement and Herniation into the Left Atrium by an Atrial Septal Defect Occluder Device

The Chiari network is a fenestrated membrane consisting of threads and strands in the right atrium. First described in 1897 by anatomist Hans Chiari, 1 it is a congenital remnant of embryonic development resulting from incomplete resorption of the right valve of the sinus venosus. Found in 2% to 3% of the population, 2,3 it is generally not of clinical importance. Rarely, however, the network may be associated with serious complications such as thrombus formation, 2 embolus entrapment, 4 arrhythmia, 5 tumor development, 6 and catheter entrapment. 7 We report the entanglement of an Amplatzer septal occluder device catheter in a prominent Chiari network that was herniated into the left atrium. Transesophageal echocardiographic recognition of this before deployment and guidance during disentanglement is described below. (J Am Soc Echocardiogr 1999;12:601-3.)

Unusual Case of Prominent Chiari Network Trapped in the Left Atrium

We describe a case of an unusually prominent Chiari network in a premature neonate who was evaluated with echocardiography. The network, which is an embryologic remnant, was extensive, mobile, and moved in and out of the right ventricle. Later, tissue strands passed the foramen ovale and ultimately became trapped in the left atrium. The differential diagnosis included thrombus, tumor, vegetation, and ruptured chordae. (J Am Soc Echocardiogr 1998;11:71-3.)

Identification of an Unusual Right Atrial Mass as a Chiari Network By Biplane Transesophageal Echocardiography

An unusual right atrial mass was visualized on the transthoracic and single planar transesophageal echocardiograms of a young female patient. Biplane transesophageal echocardiography, however, clearly demonstrated this structure to be a prominent Chiari network. Large eustachian valves and Chiari networks may mimic tumor or thrombus formation when conventional noninvasive diagnostic techniques are used. Multiplanar imaging can be essential in defining anatomical relationships of normal variant structures, eliminating concern for pathological entities and the need for further invasive work‐up.

Identification of Chiari's Network with Transesophageal Echocardiography

A prominent Chiari's network may be difficult to distinguish from pathologic right atrial masses on transthoracic echocardiography. We report a 38-year-old woman who had a cerebrovascular accident. Transthoracic echocardiogram revealed an atrial septal aneurysm and a mobile right atrial mass. This mass was correctly identified as Chiari's network on the basis of the transesophageal echocardiographic findings of a broad base of attachment in the right atrium and filamentous nature of the mass. These findings were confirmed at surgery.