The most common type of total anomalous pulmonary venous connection is –
**Core Concept**
Total anomalous pulmonary venous connection (TAPVC) is a congenital heart defect where all four pulmonary veins connect anomalously to the systemic venous system, rather than normally connecting to the left atrium. This results in oxygenated blood from the lungs returning to the right atrium, instead of the left atrium, leading to desaturation of systemic circulation.
**Why the Correct Answer is Right**
The most common type of TAPVC is supracardiac, accounting for approximately 50% of cases. In this type, the pulmonary veins connect to the superior vena cava or the innominate vein, forming a common chamber before returning to the right atrium. This is due to the abnormal development of the pulmonary veins and the absence of the left atrium. The supracardiac type is the most common type of TAPVC because it is often associated with a more favorable anatomy, allowing for surgical repair.
**Why Each Wrong Option is Incorrect**
**Option A:** This option does not provide any information about the types of TAPVC, making it an incorrect choice.
**Option B:** This option may refer to another type of TAPVC, but it does not specify the most common type.
**Option C:** This option is also incorrect, as it does not accurately describe the most common type of TAPVC.
**Clinical Pearl / High-Yield Fact**
Remember that TAPVC is a cyanotic congenital heart defect, and the most common type is supracardiac. This knowledge is crucial for diagnosing and managing patients with TAPVC.
**Correct Answer: C. Supracardiac**