​Pathology - Ventricular Septal Defect (VSD)

​Pathology -  Ventricular Septal Defect (VSD)
The most prevalent congenital cardiac defect is due to the incomplete fusion of the interventricular septum with the aortic septum. It is frequently observed alongside other congenital cardiac abnormalities such as tetralogy of Fallot and transposition of the great arteries (TGA). Linked to fetal alcohol syndrome and Down syndrome, it can also arise as a consequence of myocardial infarction (MI).

Pathology: There is a structural abnormality in the ventricular septum that creates a connection between the right and left ventricles. This defect can take different forms, such as membranous ventricular septal defect (VSD) (90% of cases), infundibular VSD, and muscular VSD.
Pathophysiology refers to the study of the functional changes that occur in the body as a result of a disease or injury. At first, there is a left-to-right shunt because the resistance in the pulmonary blood vessels is lower than the resistance in the systemic blood vessels. Continued presence of a shunt leads to a chronic increase in the amount of blood flowing to the right side of the heart, causing a progressive rise in pulmonary vascular resistance. with the potential reversal of the shunt from left to right
Minor ventricular septal defects (VSDs) typically do not exhibit any symptoms. In babies, moderate to massive ventricular septal defects (VSDs) might manifest as heart failure.

Symptoms and signs 
Failure to thrive, perspiration during feeding, or recurrent respiratory infections. Among elderly patients, dyspnea and cyanosis may manifest after physical exertion.

A physical examination may reveal a loud, continuous heart murmur at the lower left edge of the sternum (if the ventricular septal defect is significant) and an enlargement of the right ventricle.
Complications may arise, such as pulmonary hypertension, late cyanosis, aortic insufficiency, and endocarditis.

Therapy 
Minor ventricular septal defects (VSDs) have the potential to heal spontaneously. Surgery is recommended for big ventricular septal defects (VSDs) with shunt fractions more than 1.5 or in cases when the patient has experienced shunt reversal accompanied by Eisenmenger syndrome.

Eisenmenger syndrome is characterized by the development of cyanosis in adulthood due to a reversal of blood flow from the left side of the heart to the right side. The condition is a result of untreated, physiologically significant ventricular septal defects (VSDs), atrial septal defects (ASDs), and patent ductus arteriosus (PDAs).