Answer to quiz: A round cyst-like structure in the right atrium Correct answer is #2: Atrial septal aneurysm (ASA) protruding from the left atrium into the right atrium. This conclusion became clear after receiving other echocardiographic images, particularly the apical four chamber view (Fig. 1). It is possible to notice on this image that in fact this formation is not a cyst, but a deep protrusion of the atrial septum in its central part from left to right. This protrusion remains practically the same by its size during both systole and diastole. Using the color Doppler we could not visualize the shunt of blood in the atrium from left to right side or vice versa, so it was not possible to prove the presence of a patent foramen ovale (PFO) or atrial septal defect, which often happens in such cases.

Quiz: A round cyst-like structure in the right atrium Case A 43-year-old woman with a history of severe COVID infection and 6-week treatment in the intensive care unit (2 years ago) visited her family doctor complaining on nonspecific chest pain and palpitations. On 12-lead electrocardiogram, a few
premature atrial contractions were recorded. Doctor recommended to perform an echocardiography (echo). During the echo-examination normal cardiac
chambers with good contractility and normal structure and function of valves were visualized. But from the modified apical right ventricular inflow view
a round cyst-like structure was revealed in the right atrium not entering the right ventricle but partially obstructing the right ventricular inflow tract