Congenital Heart Disorders – Disorders with Increase Pulmonary Blood Flow
Classification of Congenital Heart Diseases
Congenital Heart disorders were formerly classified as either cyanotic and acyanotic heart diseases. Cyanotic heart diseases occur when deoxygenated blood is shunted from the venous circulation to the arterial circulation, resulting to the bluish discoloration of the skin (cyanosis) due to decreased oxygen levels in the systemic circulation. With this classification, blood is shunted directly from the right to the left part of the heart. Acyanotic heart diseases involve narrowing or stricture of the blood that moves the blood from the arterial to the venous circulation (left to right shunt). However, some patients with heart diseases under the cyanotic type do not show cyanosis until they are seriously ill. And those with cyanotic heart diseases can also exhibit cyanosis.
Because of the confusion the former system created a second classification system has been established. This classification system identifies four types of disorders which is classified according to the blood flow patterns of the disease not their signs and symptoms. The following are:
- Increased pulmonary blood flow
- Obstruction to blood flow
- Mixed blood flow
- Decreased pulmonary blood flow
Congenital heart disorders classified with increased pulmonary blood flow follows the movement pattern of the blood from the left side of the heart (greater pressure) to the right side of the heart (lower pressure). This abnormal blood movement is due to an opening between two systems or arteries. Disorders of this type include the following:
- Ventricular Septal Defect (VSD)
With this cardiovascular defect, an opening between the two ventricles is present. Because pressure in the left side of the heart is greater than the right side, blood will be shunted from the left to the right. Thus, more blood enters the pulmonary circulation (from the right side) and less to the aorta.
- Easy fatigability
- Loud harsh pansystolic murmur at the left sterna border
- Atrial Septal Defect (ASD)
Presence of an opening in between the two atria resulting to the shunt of the oxygenated blood from the left side of the heart to the right side is noted with ASD. This congenital heart disease is more common in girls than boys.
- Harsh systolic murmur (at 2nd or 3rd interspace)
- Second heart sound auscultated as split (fixed splitting)
- Atrioventricular Canal Defect (AVC) or Endocardial Cushion Defect
Endocardial cushion is the septum of the heart at the junction of the atrium and ventricle. When this endocardial cushion fails to fuse the disorder is called AVC or Endocardial Cushion Defect.
- Patent Ductus Arteriosus (PDA)
Ductus arteriosus is a fetal accessory that links the pulmonary artery to the aorta. Failure of this accessory structure to close at birth (Patent Ductus Arteriosus) will result to the shunting of the oxygenated blood from the aorta to the pulmonary artery. Blood is shunted from the aorta to the pulmonary artery because of the increase pressure in the aorta.
- Wide pulse pressure
- Continuous machinery murmur on auscultation
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