Question

1. What is the pathophysiology of cyanotic Vs non-cyanotic congenital heart defects?

2. Explain what is Fallot tetralogy (ToF) and how it compares to any other cyanotic congenital heart disease (any other you want)

3. Explain what is a Blalock-Taussig shunt, how it relates to fetal circulation and how/why it’s done in certain cyanotic heart diseases. Briefly explain other surgical procedure(s) that fixes a cyanotic heart defect.

Answer 1

1. In cyanotic heart defects, less oxygen-rich blood reaches the tissues of the body,because of which there is development of a bluish tint to the skin, lips, and nail beds, this condition occurs due,to  deoxygenated blood bypassing the lungs and entering the systemic circulation, or a mixture of oxygenated and unoxygenated blood entering the systemic circulation. It is type congenital heart defect, meaning heart problems or abnormalities that have been present since birth. Examples include, tetralogy of fallot.

There are other type of congenital heart defect, in which there is no  interference with the amount of oxygen or blood that reaches the tissues of the body known as, acyanotic heart defects, in which a bluish tint of the skin isn't common in babies, example ventricular septic defect.

2. Fallot tetralogy is type of defects, which affect the structure of the heart which  causes oxygen-poor blood to flow out of the heart and to the rest of the body. Infants and children with tetralogy of Fallot usually have blue-tinged skin because their blood doesn't carry enough oxygen, these conditions may occur due to various of reasons like, a very large opening in the wall between the lower heart chambers, narrowing of pulmonary valves or due to thickening of ventricles.

In other type of defect known as ventral septal defect, occurs due an opening in the heart wall (septum), as opposed to fallot tetralogy which occurs due to opening in the wall between ventricles.

3.Blalock-Taussig shunts, is a type of procedure  are used for defects that affect the flow of blood from the right ventricle, through the pulmonary artery, and to the lung, this shunt creates a alternative pathway that allows enough blood to pass through the lungs and pick up more oxygen.

In this procedure,  a connection is made between the first artery that branches off the aorta called the right subclavian artery and the right pulmonary artery. Some of the blood traveling through the aorta towards the body will "shunt" through this connection and flow into the pulmonary artery to receive oxygen. This type of procedure helps in babies with cyanotic heart defect, where deoxygenated blood by passes the lungs. In babies with cyanotic heart defect, The Blalock-Taussig shunt helps babies get enough oxygen until they can have surgery to fix the defect.