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 Table of Contents  
INTERESTING CASE REPORT
Year : 2021  |  Volume : 5  |  Issue : 1  |  Page : 50-53

Cardiac Magnetic Resonance Imaging to Detect Right Atrial Thrombus in Right Ventricular Endomyocardial Fibrosis


Department of Cardiology, Little Flower Hospital and Research Centre, Angamaly, Kerala, India

Date of Submission23-Apr-2020
Date of Decision30-Aug-2020
Date of Acceptance18-Sep-2020
Date of Web Publication08-Mar-2021

Correspondence Address:
Dr. Stigi Joseph
Department of Cardiology, Little Flower Hospital and Research Centre, Angamaly, Kerala
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jiae.jiae_18_20

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  Abstract 

Tropical endomyocardial fibrosis (EMF) is endemic in southern districts of Kerala state in India, and sporadic cases are reported from other parts of Kerala. Transthoracic echocardiogram (TTE) is the initial imaging tool and is diagnostic for this condition. The inherent limitation of TTE is its limited sensitivity in the detection of intracardiac thrombus. Transthoracic echocardiography, contrast-enhanced cardiac computed tomography, and cardiac magnetic resonance imaging (CMR) are the imaging modalities for the detection of intracardiac thrombus. This report describes a 46-year-old male with right ventricular EMF (RVEMF) who presented with right heart failure. The TTE diagnosed RVEMF but failed to demonstrate the right atrial thrombus which was clearly seen on CMR. The merits of different imaging modalities for the detection of intracardiac thrombus are discussed.

Keywords: Contrast-enhanced computed tomography scan, delayed gadolinium hyperenhanced cardiac magnetic resonance imaging, endomyocardial fibrosis, transesophageal echocardiography, transthoracic echocardiography


How to cite this article:
Joseph S, Varghese AC, Narayanan S, Rajesh G. Cardiac Magnetic Resonance Imaging to Detect Right Atrial Thrombus in Right Ventricular Endomyocardial Fibrosis. J Indian Acad Echocardiogr Cardiovasc Imaging 2021;5:50-3

How to cite this URL:
Joseph S, Varghese AC, Narayanan S, Rajesh G. Cardiac Magnetic Resonance Imaging to Detect Right Atrial Thrombus in Right Ventricular Endomyocardial Fibrosis. J Indian Acad Echocardiogr Cardiovasc Imaging [serial online] 2021 [cited 2021 Jul 23];5:50-3. Available from: https://www.jiaecho.org/text.asp?2021/5/1/50/310978


  Introduction Top


The southern districts of Kerala state in India have been a hot spot of tropical endomyocardial fibrosis (EMF). The prevalence is coming down, probably due to improving living standards.[1] Patients with EMF may present with biventricular, isolated right ventricular (RV) or left ventricular (LV) involvement. Apical obliteration of the involved chamber with atrioventricular (AV) valve regurgitations and markedly dilated atrial chambers are characteristic echocardiographic features. Atrial fibrillation and calcification of the obliterated cavity occur in the late stages.[1],[2] Thrombus formation in the atrial chamber may occur even without atrial fibrillation. Transthoracic echocardiography (TTE) has low sensitivity in detecting atrial thrombus. Transesophageal echocardiography is the imaging modality of choice for atrial thrombus; cardiac magnetic resonance imaging (CMR) and contrast-enhanced cardiac computed tomography (CT) scan are other imaging options with high sensitivity and specificity.


  Clinical Presentation Top


A 46-year-old male presented with gradually progressive pedal edema. He was otherwise asymptomatic. Clinical evaluation showed bilateral pitting pedal edema, an irregular pulse with normal rate, and normal blood pressure. Jugular venous pulse was elevated with prominent “V” wave, varying S1 and 3/6 systolic murmur at the tricuspid area. Electrocardiogram (ECG) showed atrial fibrillation with controlled ventricular rate, “qr” pattern in V1 with right axis deviation.

Transthoracic echocardiography [Figure 1] and [Figure 2] showed hugely dilated right atrium and RV inflow, obliteration of RV apex with specks of calcium, moderate tricuspid regurgitation, normal RV systolic pressure, and moderate pericardial effusion. He was diagnosed as a case of RVEMF. For further evaluation, he underwent CMR. The contrast-enhanced CMR [Figure 3] showed dilated right atrium and RV inflow, obliterated RV apex, and pericardial effusion. An organized thrombus was seen at the right atrial (RA) free wall which was not seen in the transthoracic echocardiogram.
Figure 1: Transthoracic echocardiographic parasternal short-axis view showing dilated right atrium. Thrombus is not seen in this view.

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Figure 2: Transthoracic echocardiography showing dilated right atrium, right ventricular inflow, obliterated right ventricular apex, and pericardial effusion. This does not show any right atrial thrombus.

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Figure 3: Contrast-enhanced cardiac magnetic resonance imaging showing dilated right atrium, right ventricular inflow, obliterated right ventricular apex, and pericardial effusion. The organized right atrial clot is well seen which is not seen in the echocardiogram

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  Discussion Top


Patients with EMF may present with biventricular, isolated RV or LV involvement. ECG changes suggest an atrial abnormality, both pressure and volume overload.[2] Tall and peaked “p” in lead II, qR pattern in V1 (with diminutive R in V1), and low-voltage complexes from pericardial effusion are the usual ECG features of RVEMF. The early transition of S in V1 to R in V2 is also a suggestive finding.[2] Atrial fibrillation is an end-stage atrial rhythm and may occur in up to 50% of the patients. RVEMF patients usually have atrial fibrillation with controlled ventricular rate, whereas LVEMF patients more often have atrial fibrillation with rapid ventricular rate.[2]

Transthoracic echocardiography is the initial imaging modality and is diagnostic. Apical obliteration of the ventricular chamber involved, AV valve regurgitation, hugely dilated ventricular inflow, and atrial chamber are the typical echocardiographic features. Plastering of the posterior valve leaflets to ventricular endocardium and fibrosis of papillary muscles aggravate AV regurgitation.[1] Pericardial effusion is usual. Calcification of the obliterated ventricular cavity occurs in the late stages. The fibrotic obliterative process stops at the outflow of the ventricles. Histologically, the obliterative tissue has a superficial layer of mucopolysaccharides and a deeper layer of lymphatics with lymphocytic infiltrates.[1]

Right heart thrombus is rare. RV EMF is one condition usually associated with RA thrombus.[3] This is due to RA dilatation secondary to RV apical obliteration and resultant stagnation of blood. Other causes of right heart thrombus include embolization from peripheral venous source, iatrogenic causes such as indwelling catheters and pacemaker leads, RV infarction, and Behcet's disease.[3]

Although TTE is a diagnostic imaging modality for EMF, it has a low sensitivity of 40%–60% for intracardiac thrombus.[4] Transesophageal echocardiography carries a high sensitivity and specificity for detection of RA and appendage thrombus.[5] A delayed contrast-enhanced CT scan also has high sensitivity and specificity for intracardiac thrombus.[6] Delayed contrast-enhanced CT scan imaging is done 1 min after contrast injection to differentiate the filling defect due to sluggish flow from true filling defect due to a thrombus.[7] CMR is another useful imaging modality for the detection of intracardiac thrombus. Depending on the study technique, the sensitivity and specificity for the detection of intracardiac thrombus with CMR vary.[8] Cine CMR has a sensitivity of 66.6% and specificity of 92.5%, and contrast-enhanced CMR also carries similar results (sensitivity of 66.7% and specificity of 95.2%). Delayed gadolinium hyperenhancement (DHE) with long T1 of 600 ms has 100% sensitivity and 99.2% specificity.[8]

Comparative efficiency of different imaging modalities for intracardiac thrombi has been studied mostly among left-sided chamber thrombi.[9],[10] There are limited data comparing different imaging modalities for thrombus in right-sided chambers.[4]

A right heart thrombus may either be a long, thin, extremely mobile mass resembing a worm or a snake (type A) or it may be a nonmobile sessile mass (type B). Type A thrombus originates in the peripheral veins and carries a high risk for pulmonary embolism and mortality, whereas type B is in situ right heart thrombus and carries a low risk for pulmonary embolism and mortality.[11] A group neither fitting with type A or type B is also described. These type C thrombi are rare, share a similar appearance to myxoma, and are highly mobile.[11],[12]

The CMR in our patient showed RVEMF with a large organized thrombus consistent with an in situ thrombus (type B). It was not picked by TTE as it was a layered thrombus attached to the RA free wall. The patient was started on oral anticoagulants in addition to decongestive therapy for symptomatic right heart failure.


  Conclusion Top


Transthoracic echocardiography is diagnostic of RVEMF but has limited sensitivity in the detection of intracardiac thrombus. Transesophageal echocardiography, CMR (DHE) and delayed contrast-enhanced cardiac CT scan have higher sensitivity in the detection of intracardiac thrombus compared to TTE. Cardiac MRI (DHE) is superior to all other imaging modalities as it also helps in tissue characterization.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for images and other clinical information to be reported in the journal. The patient understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Vijayaraghavan G, Sivasankaran S. Tropical endomyocardial fibrosis in India: A vanishing disease! Indian J Med Res 2012;136:729-38.  Back to cited text no. 1
    
2.
Tharakan JA. Electrocardiogram in endomyocardial fibrosis. Indian Pacing Electrophysiol J 2011;11:129-33.  Back to cited text no. 2
    
3.
Mocumbi AO. Right ventricular endomyocardial fibrosis (2013 Grover Conference series). Pulm Circ 2014;4:363-9.  Back to cited text no. 3
    
4.
Turhan S, Ulas Ozcan O, Erol C. Thrombosis. Review article – Special issue. Imaging of intracardiacthrombus. Cor Vasa 2013;5:e176-83.  Back to cited text no. 4
    
5.
Suratkal V, Ahmed A. Right atrial thrombus and challenges in its management. J Assoc Physicians India 2018;66:65-8.  Back to cited text no. 5
    
6.
Weinsaft JW, Kim RJ, Ross M, Krauser D, Manoushagian S, LaBounty TM, et al. Contrast-enhanced anatomic imaging as compared to contrast-enhanced tissue characterization for detection of left ventricular thrombus. JACC Cardiovasc Imaging 2009;2:969-79.  Back to cited text no. 6
    
7.
Romero J, Husain SA, Kelesidis I, Sanz J, Medina HM, Garcia MJ. Detection of left atrial appendage thrombus by cardiac computed tomography in patients with atrial fibrillation: A meta-analysis. Circ Cardiovasc Imaging 2013;6:185-94.  Back to cited text no. 7
    
8.
Kitkungvan D, Nabi F, Ghosn MG, Dave AS, Quinones M, Zoghbi WA, et al. Detection of LA and LAA Thrombus by CMR in patients referred for pulmonary vein isolation. JACC Cardiovasc Imaging 2016;9:809-18.  Back to cited text no. 8
    
9.
Srichai MB, Junor C, Rodriguez LL, Stillman AE, Grimm RA, Lieber ML, et al. Clinical, imaging, and pathological characteristics of left ventricular thrombus: A comparison of contrast-enhanced magnetic resonance imaging, transthoracic echocardiography, and transesophageal echocardiography with surgical or pathological validation. Am Heart J 2006;152:75-84.  Back to cited text no. 9
    
10.
Manning WJ, Weintraub RM, Waksmonski CA, Haering JM, Rooney PS, Maslow AD, et al. Accuracy of transesophageal echocardiography for identifying left atrial thrombi. A prospective, intraoperative study. Ann Intern Med 1995;123:817-22.  Back to cited text no. 10
    
11.
The European Cooperative Study on the clinical significance of right heart thrombi. European Working Group on Echocardiography. Eur Heart J 1989;10:1046-59.  Back to cited text no. 11
    
12.
Finlayson GN. Right heart thrombi: Consider the cause. Can J Cardiol 2008;24:888.  Back to cited text no. 12
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]



 

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