Tetralogy of Fallot Nursing NCLEX | Congenital Heart Disease Defects

Tetralogy of Fallot is a congenital heart defect characterized by four structural defects of the heart. It's one of the most common complex congenital heart defects, occurring during fetal development. It is a cyanotic heart defect, meaning there's decreased pulmonary blood flow leading to poor blood oxygenation and a bluish tint (cyanosis) in the baby or child.

Understanding normal blood flow is key to understanding this defect. The right side of the heart pumps deoxygenated blood to the lungs, where it gets oxygenated. The left side then pumps this oxygenated blood to the rest of the body. Blood flows from the superior/inferior vena cava, right atrium, tricuspid valve, right ventricle, pulmonic valve, pulmonary artery to the lungs, then back to the left atrium via pulmonary veins, through the bicuspid (mitral) valve, left ventricle, aortic valve, and aorta to the body.

The four structural defects are: Right Ventricular Hypertrophy (R), Aortic Displacement (A), Pulmonary Stenosis (P), and Septal Defect (S), specifically a Ventricular Septal Defect (VSD). These defects cause deoxygenated and oxygenated blood to mix and reduce blood flow to the lungs, leading to a right-to-left shunt, where deoxygenated blood is pumped to the body.

Signs and symptoms collectively known as 'AFFLICT' include: Activity intolerance (leading to Tet spells), Fingernail clubbing (due to chronic hypoxia), Fatigue/Fainting easily, Lift knee-to-chest position or squatting (a compensatory mechanism during Tet spells to increase systemic vascular resistance and reduce shunting), Inability to grow (smaller for age), Cardiac sounds (harsh systolic murmur at the left sternal border due to pulmonary stenosis), and Trouble feeding and thriving (leading to low weight and developmental delays).

Treatment primarily involves surgery to fix the structural defects. This can include temporary palliative surgery (like placing a shunt or stent to increase pulmonary blood flow) or a complete repair, usually performed around 6-12 months of age. A patch is placed to correct the Ventricular Septal Defect. A medication called Alprostadil (a prostaglandin) may be given to newborns to keep the ductus arteriosus open, increasing blood flow to the lungs until surgery can be performed.