Corrective Transposition of the Great Arteries: Understanding the Risks and Complications

Corrective transposition of the great arteries (CTGA) is a rare congenital heart defect characterized by discordant connections between the ventricles and great arteries, as well as between the atria and ventricles. Despite these anatomical anomalies, blood flow often follows a near-normal pattern, with systemic venous return still directed to the pulmonary artery and oxygenated pulmonary venous blood flowing into the aorta. As a result, patients typically do not exhibit early symptoms such as cyanosis. However, this condition poses serious long-term health risks, including heart failure and progressive cardiac dysfunction.

Progressive Heart Failure Due to Anatomical Strain

In CTGA, the right ventricle is connected to the aorta and thus must pump blood to the entire body, a task it is not designed for anatomically. While the right ventricle can initially handle the volume load, it is not suited to manage the high-pressure demands of systemic circulation. Over time, this mismatch leads to ventricular dilation, myocardial fatigue, and eventually heart failure.

As the right ventricle enlarges, it can cause secondary complications such as tricuspid valve regurgitation. Structural changes in the heart alter the geometry of the tricuspid valve, impairing its ability to close properly. This regurgitation further exacerbates heart strain, creating a cycle of worsening cardiac function and increasing the risk of chronic heart failure.

Electrophysiological Risks and Arrhythmias

Increased Risk of Conduction Disorders

Patients with CTGA also face unique electrophysiological challenges. The conduction pathways in these individuals often follow an abnormal and elongated course, making them more prone to arrhythmias. One of the most concerning complications is the development of spontaneous atrioventricular (AV) block.

This condition can progress without warning and may require the implantation of a permanent pacemaker. AV block in CTGA patients can lead to severe bradycardia, syncope, and in extreme cases, sudden cardiac arrest. Therefore, regular cardiac monitoring and early intervention are crucial for managing these patients effectively.

Long-Term Management and Prognosis

Although some individuals with CTGA may appear asymptomatic in early life, the long-term prognosis can be significantly affected by progressive heart failure and rhythm disturbances. Timely diagnosis, close follow-up with a cardiologist, and appropriate interventions are essential to improve quality of life and reduce the risk of life-threatening complications.