Congenitally corrected transposition of the great arteries A timely diagnosis in a "normal" life.

Abstract

Introduction: Transposition of the great arteries with congenital correction (TGA- CC) is a rare congenital heart defect, accounting for approximately 0. 0.5% of all congenital heart diseases. It is characterized by a double discordance (atrioventricular and ventriculoarterial), resulting in physiologically corrected circulation. Despite this correction, most patients develop symptoms due to associated abnormalities and, primarily, progressive dysfunction of the systemic right ventricle (RV), which can lead to early death.

Clinical Case: A 34- year- old woman, active and with no significant medical history or functional limitations, reported sporadic paroxysmal palpitations over the past two years, which had increased in frequency and for which she was prescribed bisoprolol. Chest X- ray showed the "humpback" appearance of the left margin of the cardiac silhouette, a characteristic finding in TGA- CC. Transthoracic echocardiography raised suspicion of TGA- CC when it revealed that the ventricle attached to the left atrium had morphological features of a right ventricle, including a moderator band and anterior tricuspid valve implantation. Systemic right ventricular function was preserved. Cardiac magnetic resonance imaging confirmed the diagnosis of TGA without associated defects and demonstrated good systemic right ventricular function (ejection fraction 68%) and normal left ventricle. During right catheterization, intracardiac and pulmonary vascular pressures were within normal limits.

Management: A conservative approach with ongoing outpatient follow- up was selected, given the absence of associated defects and preserved ventricular function.

Discussion: The presentation of asymptomatic TGA- CC until adulthood (34 years in this case) represents an atypical clinical course. Diagnosing CC- TGA in asymptomatic adults is a significant echocardiographic challenge due to the subtlety of double discordance, highlighting the importance of high clinical suspicion and the use of CMR for confirmation. The main long- term complication is the progressive dysfunction of the systemic right ventricle. It is noted that pregnancy can cause early deterioration of systemic RV function. Management is tailored to the individual, with the "arterial double switch" (anatomical repair) preferred in symptomatic patients, while conservative follow- up may be appropriate for asymptomatic individuals.