Key points
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Anatomic variants occurring in normal cardiac developments often simulate pathologic entities.
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Anatomic variants are particularly common in the right atrium.
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Due to the physical properties of ultrasound waves and specifics in ultrasound image reconstruction, cardiologists often encounter ultrasound image artifacts. It is particularly important to recognize such artifacts to avoid misdiagnosis of conditions ranging from aortic dissection to thrombosis and endocarditis.
| Structures potentially mimicking cardiac masses in echocardiography | ||
| Left ventricle webs, heartstrings, chords Apical trabeculations Dilated coronary sinus (PLAX view) Dilated descending aorta (A4C view) Multiple lobes of the left atrial appendage Pectinate muscles of the right/left atrial appendage Prominent moderator band Prominent crista terminalis | Nodules of Arantius Dystrophic calcification of the mitral valve Noncompaction cardiomyopathy Prominent papillary muscle Lipomatous hypertrophy of the interatrial septum Pacemaker wires Central venous catheters Valvular interventional devices | Near beam artifact Reverberation Enhancement Refraction Mirror image |
| Prominent Eustachian valve Prominent Chiari network Redundant mitral chordae or redundant leaflet tissue Prominent epicardial fat pad Apical hypertrophic cardiomyopathy Interatrial septal aneurysm Lambl’s excrescence | Occluder interatrial/interventricular devices | |
Accessory mitral valve tissue (AMWT) is a rare congenital cardiac anomaly sometimes responsible for left ventricular outflow tract (LVOT) obstruction. AMVT is most often associated with other cardiac and vascular congenital malformations such as septal defects and transposition of the great arteries ( Supplementary Video 3.1 ).
Patients with AMVT may be asymptomatic with the presence of a murmur; nonetheless, more frequently, they experience symptoms like dyspnea. Usually, patients become symptomatic when the mean gradient across the LVOT reaches 50 mmHg.
Signs of LVOT obstruction generally develop during the first decade of life in one-third of the patients and include typical symptoms. The current approach is intervention only for patients with significant LVOT obstruction (mean gradient ≥ 25 mmHg) and those undergoing correction of other congenital malformations or exploration of an intracardiac mass. For patients without significant LVOT obstruction, a follow-up with serial echocardiography to assess the progression of the gradient is indicated.
Benign lipomatous tumors of the heart are exceptionally rare. They encompass mainly lipoma and lipomatous hypertrophy of the atrial septum. Cardiac lipomatosis is characterized by the accumulation of nonencapsulated mature adipose tissue caused by hyperplasia of lipocytes. The etiology is unknown, but it may be associated with obesity and advancing age. The most frequent manifestation is lipomatous hypertrophy of the interatrial septum, but massive epicardial lipomatous hypertrophy is less well documented. Although histologically benign, it has been reported to cause cardiac tamponade, requiring decompressive pericardiectomy. Usually, lipomatosis remains asymptomatic and represents an incidental finding on echocardiography. Furthermore, it can be mistaken for other benign or malignant cardiac tumors, leading to unwarranted radical surgical resection ( Supplementary Video 3.2 ).
The usual imaging to evaluate lipomatous hypertrophy is transthoracic and transesophageal echocardiography, where the septum appears unusually thick and spares the membrane of the fossa ovalis. Surgical resection is essentially not necessary and should be reserved for patients who show evidence of right or left outflow obstruction or vena cava superior obstruction .
Persistent left superior vena cava (PLSVC) is a rare congenital anomaly; nevertheless, it is the most common abnormality of the thoracic venous system and the commonest cause of a dilated coronary sinus. Two types of PLSVC are known in the literature. In 92% of cases, PLSVC is connected to the right atrium through the coronary sinus without significant hemodynamic consequences, while in 8% of cases, PLSVC connects directly or through the pulmonary veins to the left atrium, causing a right-to-left shunt. It is most commonly an isolated finding but can be associated with other congenital heart defects. PLSVC should be suspected when a dilated coronary sinus is identified via echocardiography. This is often discovered incidentally during an echocardiographic examination or other cardiovascular imaging because it is almost always asymptomatic. Therefore the evidence of a dilated coronary sinus must always be investigated in search of a congenital malformation and especially PLSVC. Usually, agitated saline injected into the brachial left vein drains through the abnormal connection between the left-sided venous return and the coronary sinus, where the bubbles can be clearly seen first in the coronary sinus and the successive opacification of the right atrium. However, considering that physicians should attempt to rule out causes of right atrial pressure/volume overload such as atrial septal defect, coronary fistula, and other anomalous drainage patterns into the coronary sinus, nowadays, multislice computed tomography is more frequently applied by cardiologists and radiologists to visualize the coronary anatomy, coronary anomalies, and aortic pathology .
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