Left To Right Shunt Lesions: Ventricular Septal Defect (VSD)
Decreased Cardiac Output
This is the commonest congenital heart disease in the pediatric age group. This is characterized by one or more defects in the ventricular septum. The main types are:
- Infracristal (Subarotic)
- Supracristal (subpulmonic)
- Canal type, and
- Muscular defect
Crista is considered to be a part of the right ventricle, which demarcates the outflow tract from the body. Infracristal type of defects are the commonest. Ventricular septal defect may occur as an isolated anomaly in the majority, or in association with other cardiac anomalies such as ASD, right ventricular outflow obstruction, coarctation of aorta and transposition of great vessels. The blood flows from left ventricle to the right and then to the pulmonary circulation. This leads on to enlargement of left and right ventricles, pulmonary artery and the left atrium.
Large VSDs can result in congestive cardiac failure in infancy. Recurrent respiratory infection and failure to thrive may also be noticed. Those who survive develop varying degrees of pulmonary hypertension. Small VSDs are asymptomatic and they are detected on routine examination. Moderate VSDs present with palpitation and recurrent respiratory infections.
A 6 months Old Patient
Clinical Features And Treatment
Small VSDs are characterized by a harsh pansystolic murmur associated with thrill, best heard in the left third and fourth intercostals spaces. Moderate and large VSDs produce pansystolic murmur and cardiac enlargement. The apex beat is forcible with hyperactive precordium. Pulmonary artery pulsation may be felt. There may be left ventricular third heart sound and mid-diastolic murmur heard over the cardiac apex, suggestive of increased blood flow across the mitral valve.
Complications may occur. These include congestive cardiac failure, Eisenmenger syndrome, infective endocarditis and aortic incompetence due to prolapsed of the aortic valve cusp through the defect.
Small VSD usually does not require surgery, but in view of the complication of infective endocarditis, some surgeons prefer to close small VSDs also. Moderate and large VSDs have to be closed surgically. More than 80% of small VSDs close spontaneously by the age of 5-7 years. The size of moderate and large VSDs may also reduce in course of time of the defect may even close completely.
© 2014 Funom Theophilus Makama