Case report: We present a case of an asymptomatic patient with atrial flutter and giant right atrial myxoma. 60-year-old male was referred to a cardiologist after a preoperative assessment where atrial flutter was verified for the first time. The patient was asymptomatic, and his history was unremarkable, without cardiovascular risk factors or burdening family history. During the examination, right atrial (RA) flutter with fast ventricular response was verified. During the echocardiography (ECHO), a large (9x10cm), isoechogenic, hypermobile, lobulated, and partially calcified mass was verified on the free anterior/lateral wall of the RA. During diastole, the mass completely protruded through the tricuspid valve in the right ventricle cavity but did not reach the right ventricular outflow tract; during systole, it protruded into the superior vena cava. Coronary angiography was performed, and coronary artery disease was excluded. Blood analysis was unremarkable, except for elevated brain natriuretic peptide (NT-proBNP 1877pg/mL). The patient was referred to a cardiac surgeon, and the tumor was removed. Due to severe tricuspid annular dilatation and tricuspid regurgitation (TR), tricuspid valvuloplasty with tricuspid ring implantation was performed. Postoperative recovery was unremarkable. Pathological analysis revealed a large tumor consisting of mesenchymal cells and a prominent stroma with areas of bleeding, coinciding with myxoma. Seven days after surgery, ECHO was performed which confirmed dilated RA with mild TR, and no residual tumor masses. A second check-up was performed after three months, revealing regression in the size of the RA, minimal TR, and the patient reported no symptoms.
Conclusion: We present this case because of the unusual localization of the tumor, its size, and the complete absence of symptoms (1). Atrial flutter acted as a compensatory mechanism, as it enabled right ventricle filling during early diastole, resulting in absence of symptoms. Effective atrial contraction would occlude the tricuspid valve and drastically reduce the filling of the right ventricle.