Final answer:
Tetralogy of Fallot is a congenital heart defect involving anatomical abnormalities and hemodynamic changes that lead to symptoms like heart murmurs, dyspnea, and cyanosis. It reduces blood oxygen saturation and is treated surgically, though it has significant mortality rates.
Step-by-step explanation:
Classification and Hemodynamic Changes in Tetralogy of Fallot
Tetralogy of Fallot (TOF) is a congenital heart defect with several key features, primarily involving four anatomical abnormalities of the heart, although not all patients exhibit all four. These features include: pulmonary infundibular stenosis hindering blood flow from the right ventricle to the lungs, overriding aorta positioned above the ventricular septum, a ventricular septal defect allowing oxygen-poor and oxygen-rich blood to mix, and right ventricular hypertrophy as a compensatory mechanism to overcome the obstruction. The combination of these defects results in significant hemodynamic changes. As the pulmonary trunk is obstructed, less blood reaches the lungs for oxygenation, and the mixing of oxygen-poor blood from the right ventricle with the oxygen-rich blood from the left ventricle through the ventricular septal defect leads to decreased oxygen saturation of blood throughout the body.
Symptoms manifesting from these hemodynamic alterations include heart murmurs, dyspnea, and cyanosis, which may lead to a condition colloquially referred to as "blue baby" syndrome post-birth. Additionally, polycythemia may occur as a compensatory response to chronic hypoxemia. Diagnosis is primarily made via echocardiography. The occurrence of tetralogy of Fallot is about 400 cases per million live births. Treatment involves surgical intervention to correct the anatomical defects and improve oxygenation. Despite surgical treatment, the mortality rates are of concern with survival rates decreasing with age.