How to cite this article: Tempe DK, Garg M, Dutta D, Virmani S, Agarwal S. Right atrial spontaneous echo-contrast: Transesophageal echocardiographic features. Ann Card Anaesth 2011;14:55-7
How to cite this URL: Tempe DK, Garg M, Dutta D, Virmani S, Agarwal S. Right atrial spontaneous echo-contrast: Transesophageal echocardiographic features. Ann Card Anaesth [serial online] 2011 [cited 2021 Dec 4];14:55-7. Available from: https://www.annals.in/text.asp?2011/14/1/55/74402
A 37-year-old male presented with the complaints of episodes of dyspnea (New York Heart Association class-III), fatigue, palpitation, pain in the hypochondrium, and swelling of the lower limbs. On routine physical examination, the radial pulse was 92 beats/min, irregularly irregular, and the blood pressure was 108/60 mmHg. Hepatomegaly as well as pitting edema of both the lower limbs were present. On auscultation, pansystolic murmur was present in the mitral area that was conducted to the left axilla. Preoperative transthoracic echocardiography revealed severe mitral regurgitation (MR) with eccentric jet of 10 cm 2 . Severe tricuspid regurgitation (TR) with right ventricular systolic pressure (RVSP) 60 mmHg was also reported. Liver function tests were deranged and abdominal ultrasonography revealed congestive hepatomegaly and ascites. The patient was scheduled for mitral valve replacement after maximal decongestion. A standard anesthesia and cardiopulmonary bypass (CPB) technique with transesophageal echocardiography (TEE) monitoring was followed to manage the patient intraoperatively. TEE confirmed the presence of severe MR with vena contracta of 1.16 cm. In the right atrium, spontaneous echo-contrast (SEC) that swirled in a circular pattern was noted ([Figure 1], Video 1) with moderate TR, while the RVSP was 50.7 mmHg. The mitral valve was replaced with a 27 mm Carpentier−Edwards PERIMOUNT prosthesis (Edwards Lifesciences Corporation, Irvine, CA, USA). The patient was weaned from CPB with moderate inotropic support. During the post-bypass period, the TEE examination showed resolution of the right atrial SEC with trace TR ([Figure 2], Video 2). After chest closure, the patient was transferred to the ICU where rest of the postoperative course was uneventful.
SEC detected by TEE is defined as the presence of swirling echo-dense shadows within the cardiac chambers or vessels caused by increased ultrasonic backscatter due to stasis of cellular components. It has been well described in the left atrium in patients with atrial fibrillation or mitral stenosis, but is seen occasionally in the right atrium or left ventricle (LV).
Figure 1 :Mid-esophageal four chamber view at 0° showing the right atrial spontaneous echo-contrast. The mitral valve is thickened and calcified with minimal spontaneous echo-contrast in the left atrium (RA: right atrium, LA: left atrium, RV: right ventricle, LV: left ventricle)
Figure 2 :Mid-esophageal four chamber view at 0° after mitral valve replacement showing disappearance of the right atrial spontaneous echo-contrast and a bioprosthetic mitral valve in situ (RA: right atrium, LA: left atrium, RV: right ventricle, LV: left ventricle)
In a series of 648 consecutive patients undergoing TEE, DeGeorgia et al.  have reported right atrial SEC in only 8 (1.2%) patients, whereas 50 (7.7%) patients had left atrial SEC. They concluded that right atrial enlargement, markedly elevated right ventricular pressure, atrial fibrillation, and TR are the most commonly associated factors with right atrial SEC. In the present patient, all these factors were present and may have been responsible for the SEC in the right atrium. However, it is relatively common to identify one or more of these factors at TEE in patients who do not have right atrial SEC; hence, other factors such as abnormal blood rheology because of elevated fibrinogens levels may be involved in the genesis of SEC. 
In another series of 580 consecutive patients for the assessment of cardioversion using TEE, Bashir et al.  found a prevalence of right atrial SEC in 14% of patients with atrial arrhythmia. They also reported that the right atrial thrombi are a rare finding and were seen in less than 1% of patients with atrial arrhythmia with a corresponding prevalence of left atrial thrombi 10%−15%. It has been suggested that this decreased predilection for thrombus in the right atrium/appendage among patients with atrial fibrillation may be related to larger right atrial appendage width and lack of anatomic remodeling of the right atrial appendage. 
It is of interest that severe TR does not prevent the right atrial SEC whereas severe MR tends to prevent the left atrial SEC. The explanation of these findings may relate to the higher pressure differential across the mitral valve compared to the tricuspid valve when these valves are incompetent, i.e., the high force of a regurgitant jet from LV to left atrium is more likely to prevent stasis of blood than the lower force associated with regurgitation from right ventricle to right atrium. 
It is essential to set proper gain setting for the diagnosis of SEC, as excessive gain setting can mislead the diagnosis. Beppu et al.  suggested that SEC should be graded as severe when smoke like echoes are concentrated and visible at the normal gain, whereas SEC should be graded as mild when smoke like echoes can be barely discerned at high gain. Fatkin et al.  have categorized left atrial SEC from 1+ to 4+. Their description of the severity of SEC was based on the following criteria: 1+ = mild (minimal echogenicity located in the left atrial appendage or sparsely distributed in the left atrial cavity), 2+ = mild to moderate, 3+ = moderate (dense swirling pattern in the left atrial appendage with somewhat lesser intensity in the left atrial cavity), and 4+ = severe. Such a classification has not been followed for the right atrial SEC and has been categorized simply as positive or negative.
SEC is considered a marker of a hypercoagulable state and is a manifestation of the red cell aggregation arising from an interaction between red cells and plasma proteins such as fibrinogen. SEC within the cardiac chambers is associated with an increased risk of thromboembolism.  However, most studies have focused on the relationship between left atrial SEC and systemic thromboembolic phenomenon, including silent cerebral infarction. Yasuoka et al.  have investigated the relationship between right atrial SEC and silent pulmonary embolism in 210 patients with nonvalvular atrial fibrillation and concluded that right atrial SEC may be a predictable factor for a high risk of pulmonary embolism and possibly indicate a predisposition to thrombus formation in the lower limbs.
In conclusion, echocardiographic features and clinical significance of a rare condition of right atrial SEC are presented.
Bashir M, Asher CR, Garcia MJ, Abdalla I, Jasper SE, Murray RD, et al. Right atrial spontaneous echo contrast and thrombi in atrial fibrillation: A transesophageal echocardiography study. J Am Soc Echocardiogr 2001;14:122-7. [PUBMED] [FULLTEXT]
Subramaniam B, Riley MF, Panzica PJ, Manning WJ. Transesophageal echocardiographic assessment of right atrial appendage anatomy and function: Comparison with the left atrial appendage and implications for local thrombus formation. J Am Soc Echocardiogr 2006;19:429-33. [PUBMED] [FULLTEXT]
Yasuoka Y, Naito J, Hirooka K, Chin W, Miyatake K, Kusuoka H, et al. Right atrial spontaneous echo contrast indicates a high incidence of perfusion defects in pulmonary scintigraphy in patients with atrial fibrillation. Heart Vessels 2009;24:32-6. [PUBMED] [FULLTEXT]
Correspondence Address: Deepak K Tempe Department of Anaesthesiology & Intensive Care, G. B. Pant Hospital, New Delhi 110 002 India
Source of Support: None, Conflict of Interest: None