Intracardiac Masses or “U.E.O.”
Not all masses seen in the cardiac chambers are going to be vegetations or thrombus. Even with the most experienced echocardiographer, there remains Unidentified Echogenic Objects. Having a systematic approach to assessing these intracardiac masses and a list of potential differential causes, can be helpful to nail the diagnosis.
Useful thoughts – is it there? Can it be seen from multiple planes? Left or right? What is the haemodynamic impact? Single or multiple? What else could it be? Think Sean Connery saying “MMASSH”
- mass location
- haemodynamic impact (embolize, outflow obstruction)
True masses can generally be divided to (DVT-OT):
*Infective endocarditis will be discussed separately here.
- BENIGN (75%) – Myxoma (adult, 25% cardiac tumours), Papillary fibroelastoma, Rhabdomyoma (children- Tuberous Sclerosis), Fibroma, Lipoma
- MALIGNANT – Sarcomas – angio-, fibro-, myosarcomas, Mesothelioma, Lymphoma
- Most common cardiac tumour (50% benign cardiac tumours)
- Mostly LA (75%), RA (10%), LV and RV (5%), multiple (5%)
- Mainly pedunculated, 10% sessile
- Attached at fossa ovalis
- Globular and irregular in shape (grape cluster), and heterogeneous, occasionally demonstrating cavitations and protruding frond-like extensions.
- Can prolapse through MV in diastole, impede LA emptying
- ages of 30 and 60 years, and can be sporadic, familial, or complex (syndrome myxoma)
- Can embolize
- Associated conditons: NAME, LAMB syndrome, Carney’s Complex
- generally small (<1 cm), often confused with vegetation.
- Most common benign neoplasm of cardiac valves. Second most common cardiac tumour after myxomas.
- usually single, but can be multiple.
- almost always attached to valve surfaces, particularly the aortic valve and anterior mitral valve leaflet.
- can be upstream or downstream to valves
- can embolize systemically.
- may be pedunculated with some mobility
- round, oval, or irregular with well-demarcated borders and a homogeneous texture
- Patients who have symptoms should be offered surgery as well as those who are asymptomatic and have pedunculated lesions or tumours larger than 1 cm in diameter.
- LV, intramural
- septum, anterior apex (Can be confused with thrombus), and free wall
- Appear disproportionate, irregular hypertrophy
- Benign but frequently have a malignant course infiltrative nature, causing dysrhythmias and intractable heart failure associated with dyspnea and fatigue
- Fatty cells
- Can occur any where in the heart, including pericardium (LV, RA, IAS)
- Subepicardium, subpericardium
- Mostly small, but can be large
- Can cause arrythmias, conduction problems
- preferential to the RA.
- typically spares the fossa ovalis producing a characteristic dumbbell appearance, with infiltrate in the superior and inferior portions of the atrial septum
- When the atrial septum is massively infiltrated by fat, the amount of adipose tissue in other parts of the heart is always increased – RV epicardial surface.
- thin (≤2 mm) and elongated (>3 mm) structures with independent, hypermobility seen near the leaflet’s line of closure, on the atrial side of the mitral and tricuspid valves and on the ventricular side of the aortic valve, mitral (70% to 85%) and aortic valves (62% to 90%), but also on the right-sided valves (8% to 20%).
- Small risk of embolic event. Prevalance similar between patients with cardioembolic phenomenon and non embolic phenomenon.
- Infective vegetations have a valve distribution, leaflet and chamber location and mobility similar to those of valve excrescences. Although infective vegetations are generally >3 mm in diameter, in patients with suspected endocarditis, it may be difficult to differentiate a small or an early infective mass from an excrescence. In this setting, an infective vegetation, in contrast to an excrescence, may resolve or change in appearance over time.
- Valve excrescences vs ruptured chordae tendineae. Ruptured chordae tendineae are generally >3 mm thick and disrupt valve function (regurgitation, prolapse)
Pitfalls- anatomical variants, artifacts
- Calcification (cords, muscle, valves)
- Moderator band
- Cardiac suture lines (heart transplant)
- Redundant valvular apparatus, leaflets
- Atrial cords
- Pectinate muscles in LA appendage
- Crista terminalis – dense muscle ridge that
runs along the origin of the SVC, IVC and continues cephalad to
open into the RA appendage
- Eustachian valve (IVC) – incompetent
valve flap close to the orifice of the IVC.
- Dilated coronary sinus (persistent left SVC)
- Lambl’s excrescences
- Chiari network – network of fibres with attachments extending from the region of the crista terminalis to the eustachian valve
or floor of the RA
PLAX view showing dilated coronary sinus. The descending aorta lies beneath it. This can resemble a mass in the left atrium. Associated with left SVC (think of this when the left sided CVC you have just inserted, takes a different path..). This can be confirmed by injecting agitated saline and visualising bubbles in the coronary sinus.
Chiari network seen in this TOE bicaval view.
Lambl’s excrescences of the aortic valve which can be mistaken for a vegetation. Note how it appears thin and long.
Distinguishing one mass from another can be quite tricky. Like anything in echocardiography, it is useful to correlate findings with the clinical picture. Here is a useful slide..
Intravenous contrast can be used to identify certain pathologies including thrombus, calcified papillary muscles, non-compaction cardiomyopathy, trebeculations. It is also important to understand the principles of various artifacts which can resemble mass lesions. Therefore, being able to see a suspicious mass in more than one echo view, would make it less likely to be an artifact.
Thrombus or not?
Compare these two loops of the left atrial appendage. The first patient has atrial fibrillation undergoing CABG. The second patient has had a heart transplant. Notice any difference between the LAA?
Up close and personal with the LAA during CABG with LAA thrombus seen.
LAA in a post heart transplant patient whereby the appendage has been removed to facilitate the creation of the left atrial cuff for anastamosis.
Using pulsed wave doppler, atrial contraction velocities can be assessed to determine LAA function as seen here..
Reduced flow velocities <40cm/s during atrial contraction.
A case of “UEO”
This is an example of a “UEO” in a patient, who unfortunately, did not have a post mortem. This man was in his 70’s, who presented with back pain and multi-system organ failure of unknown aetiology. He grew group G strep from an embolic lesion from his foot but never had a positive blood culture.
Multiple mobile masses attached to the ventricular surface of the mitral valve.
- The Echocardiographic Evaluation of Intracardiac Masses: A Review. JASE 2006
- Recommendations for echocardiography use in the diagnosis and management of cardiac sources of embolism. EHJ 2010
- Valve Excrescences: Prevalence, Evolution and Risk for Cardioembolism. Carlos A. Roldan et al. J Am Coll Cardiol. 1997;30(5):1308-1314
- Papillary Fibroelastoma of the Aortic Valve. Operative Approaches upon Incidental Discovery. Raja R. Gopaldas et al. Tex Heart Inst J. 2009; 36(2): 160–163
- Agmon Y, Khandheria B, Gentile F, Seward J. Echocardiographic assessment of the left atrial appendage. J Am Coll Cardiol. 1999;34(7):1867-1877.