Introduction: Congenitally Corrected Transposition of the Great Arteries (CCTGA) is a rare defect consis-ting in the abnormal twisting of the heart during fetal development. As a result, the two ventricles and their valves are reversed. CCTGA is frequently associated with other cardiac abnormalities. 25% of patients are developing heart failure related to perfusion mismatch (the morphological left ventricle is supplied by a single coronary artery) and to the progressive deterioration of the structural right ventricle situated on the systemic side of the circulation.

Methods: A 45-year-old male was referred to our ho-spital for fatigue and dyspnea, ocurring in the last five months. Physical examination revealed tachypnea, a slightly intense systolic murmur at the apex, and pul-monary congestion, in the absence of cyanosis, pe-ripheral edema or jugular venous distension. Heart rate and blood pressure were normal. Usual laboratory work-up indicated increased levels of NT-proBNP, without any other abnormalities. ECG presented signs of pressure overload of the systemic ventricle. Transtho-racic echocardiography (TTE) highly suggested the diagnosis of CCTGA, due to the atrioventricular valve displacement, with the morphological tricuspid valve closer to the apex in 4-chamber view. TTE showed also dilated and dysfunctional left ventricle, mild left atrio-ventricular regurgitation, and normally functional ri-ght ventricle.

Results: Cardiac computed tomography emphasized a specific feature of CCTGA: the parallel emergence of the aorta and pulmonary trunk, with the aortic arch crossing over the left pulmonary artery. Cardiac mag-netic resonance imaging confirmed dilatation and low ejection fraction of the systemic ventricle (20%), and displayed presence of trabeculations and the modera-tor band in the systemic ventricle. None of these eva-luations found additional cardiac structural anomalies. Thus, patient was diagnosed with heart failure due to isolated CCTGA.

Conclusions: Discussions and relevance of case report. This case emphasizes a very rare cause of heart failu-re in adults. CCTGA is reported in 0.5-1% of all con-genital diseases, especially in males. Isolated CCTGA accounts for less than 10% of all cases, and represents the phenotype that is usually diagnosed in adulthood. In the absence of associated anomalies, the prognosis of these patients is particularly affected by the occur-rence of heart failure in the 4th or 5th decade of life. Meanwhile, this case highlights the importance of a multimodal approach in CCTGA, and the specific con-tribution of each imaging method in the process of an accurate diagnosis.