Giant LA is a rarely seen in clinical practice, usually associated with rheumatic mitral valve disease [11]. Giant LA is uncommonly related with severe mitral stenosis [12], but most often is related with mitral regurgitation or mixed mitral disease [2]. Giant LA is defined by Kothari as LA diameter more than 8cm [11]. Other investigators [3,13] have used decreased LA diameter (more than 6.5cm) for the definition of giant LA. It was first described in 1849 by Hewett in autopsy series of mitral valve disease [14]. The mechanism of formation of giant LA is proposed due to rheumatic pancarditis because of the strong relation with rheumatic heart disease. Rheumatic pancarditis damages whole heart, including both atria by causing chronic inflammation, fibrosis within the walls with consecutive weakening of its walls. In such conditions LA enlarges more easily [2,15,16]. Intracavitary chronic pressure overload and volume overload produced by mitral valve disease are additional factors for LA enlargement. AF secondary to LA enlargement is always present. AF causes further growth of LA size due to diffuse atrophy of atrial muscle [15]. Both factors, LA wall weakening produced by rheumatic pancarditis and pressure overload produced by stenosis of mitral prosthesis were involved in development of giant LA in our patient. Permanent AF additionally caused further LA enlargement. Complications of giant atria include thromboembolism, AF, hemodynamic, respiratory complications, intracardiac and extracardiac compression symptoms [2,15,17]. Increased LA pressure is transmitted retrograde into pulmonary veins and capillaries and in the end into pulmonary arteries with consecutive increased pulmonary pressure enough to produce pulmonary edema. Pulmonary hypertension leads to increased right ventricular systolic pressure and to right heart failure [18]. Cardiac output can be reduced due to compression of the posterior and lateral wall of LV by severely enlarged LA [17], as it was in our case. In our patient, congestive heart failure symptoms were present, while extra cardiac compressive symptoms or thromboembolic events were absent.

Initial diagnostic tools are imaging modalities. TTE is most feasible and best non-invasive method to establish diagnose, to monitor MV disease progression and to assess LA size [4]. Additional imaging modalities, such magnetic resonance imaging (MRI) or cardiac CT are reliable in providing a precise measurement of LA size and in assessing its relations with surrounding organs. They are also helpful in diagnosing a thrombus in left atrial appendage or LA cavity [19]. There are several reports of giant LA described before [2,15,16,20,21]. The largest reported LA size was 22.3x19.2x20.1cm on MRI in a 50-year-old female patient with rheumatic mitral valve disease [20]. In our case, the maximal diameter of LA was smaller compared to this case and was 17cm on CT scan.

Role of medical therapy is limited to antiarrhythmics, anticoagulation and heart failure therapy. Management of most patients with giant LA is surgery, presented by mitral valve replacement with or without LA volume reduction [17]. Presence of a giant LA significantly increases mortality rates in mitral valve surgery, from 7% to 20% [22]. Delaying mitral valve replacement surgery may lead to deadly outcome. When surgery is delayed, elevated pulmonary pressure leads to to elevation in right heart pressure and this critically affects mortality rates [16]. Optimal timing is of vital importance. We advised our patient to undergo cardiac surgery on numerous occasions, but she has been continuously refusing operation.

The EV is an embryologic remnant of IVC valve, luying at junction of IVC and inferior RA. In fetal heart directs oxygenated blood from IVC towards foramen ovale and left atrium into systemic circulation. After birth, following closure of foramen ovale, EV has no particular function in adults and disappears completely in most of the cases. Sometimes, on echocardiographic examinations the EV may appear as a leaflike linear structure from orifice of IVC [23]. However, prominent EV is rarely seen on echocardiography with different presentations in shape, thickness and size [7]. Prominent EV is defined as a prominence over 1 cm into the RA [23]. Our patient had very elongated (at least 6 cm) giant EV extending from IVC to inferior portion of the interatrial septum, which seemed on echocardiography as a septal structure dividing the cavity of RA into two chambers. Such echocardiographic appearance of a divided RA cavity by giant EV has been reported before in very few case reports [7-9]. The septation created by the giant EV is generally incomplete, thus this condition is hemodynamical­ly insignificant in most adults, as it was in our case [24]. Diagnostic pitfalls with EV variants mimicking pathology on echocardiography are often reported in the medical literature. Knowledge about anatomic variants of EV ensures accurate interpretation of echo­cardiographic findings avoiding misinterpretation from pathology. On pre-operative echocardiography, giant EV should be accurately identified as benign structure, especially should be differentiated from cor triatriatum dexter in order to avoid unnecessary surgical correction [7-10,23-25].

In summary, giant LA is extremely rarely observed in present era. Generally it is due to severe rheumatic mitral valve disease. TTE is accurate noninvasive method to diagnose and monitor the mitral valve disease progression and to evaluate left atrial size. Surgery is the mainstay of treatment, optimal timing can be life saving. Giant EV in adults is incidentally diagnosed by cardiac imaging techniques, usually without clinical consequences, but it is important to be recognized as benign structure on preoperative imaging. As far as we know, this seems to be a first echocardiographic report of a patient with giant LA and giant EV.

Acknowledgements: None.