1. Ventricular Septal Defect
Dr. M. A. Sofi ME; FRCP (London); FRCPEdin; FRCSEdin

2. Ventricular Septal Defect (VSD)
A ventricular septal defect (VSD) is a hole or a defect in the septum that divides the 2 lower chambers of the heart, resulting in communication between the ventricular cavities.
A VSD may occur as a primary anomaly, with or without additional major associated cardiac defects.
It may also occur as a single component of a wide variety of intracardiac anomalies, including tetralogy of Fallot (TOF), complete atrioventricular (AV) canal defects, transposition of great arteries, and corrected transpositions.
VSDs were first clinically described by Roger in 1879 ; the term maladie de Roger is still used to refer to a small asymptomatic VSD.
In 1898, Eisenmenger described a patient with VSD, cyanosis, and pulmonary hypertension. This combination has been termed the Eisenmenger complex.

3. Introduction
The most common form of CHD, accounting for up to % of patients diagnosed with CHD
Impact may range from asymptomatic to pulmonary HTN, LV volume overload and RVH
Morphology: 4 types
Membranous – most common type in adults (80%)
Muscular – most common type in young children
Complete AV septal (endocardial cushion) defects
Supracristal (subarterial)

4. Epidemiology VSDs affect 2-7% of live births.
An echocardiographic study revealed a high incidence of VSDs per 1000 newborns.
The defects in this study were small restrictive muscular VSDs, which typically spontaneously close in the first year of life
VSDs are the most common lesion in many chromosomal syndromes, including trisomy 13, trisomy 18, trisomy 21, and relatively rare syndromes
Sex-related demographics
VSDs are slightly more common in female patients than in male patients (56% vs 44%).
Race-related demographics
Reports are inconclusive regarding racial differences in the distribution of VSDs. However, the doubly committed or outlet defect occurs is most common in the Asian population. These constitute 5% of the defects in the Unites States but 30% of those reported in Japan.

5. Pathophysiology Defect size is often compared to aortic annulus
Large: > 50% of annulus size
Medium: 25-50% of annulus size
Small: <25% of annulus size

6. VSD Types

7. Pathophysiology
Restrictive VSD is typically small, such that a significant pressure gradient exists between the LV and RV (high velocity), with small shunt
Moderately restrictive VSD  moderate shunt
Large / non-restrictive VSD  large shunt
Eisenmenger VSD  irreversible pulmonary HTN and shunt may be zero or reversed

8. Natural History
Restrictive: typically does not have hemodynamic impact and may close spontaneously
Location: Subaortic may result in progressive AI
Moderately restrictive: does create LV overload and dysfunction along with variable increase in PVR
Large / non-restrictive: LV volume overload earlier in life with progressive pulmonary hypertension and ultimately Eisenmenger’s syndrome

9. Sweating while feeding Frequent respiratory infections
Symptoms:
Patients with ventricular septal defects may not have symptoms. However, if the hole is large, the baby often has symptoms related to heart failure
Fast heart rate
Sweating while feeding
Frequent respiratory infections
Shortness of breath
Fast breathing
Hard breathing
Pallor
Failure to gain weight

10. Exams and Tests
Listening with a stethoscope usually reveals a heart murmur. The loudness of the murmur is related to the size of the defect and amount of blood crossing the defect.
Chest radiograph, MRI, and ECG may all provide useful information in the workup of a ventricular septal defect (VSD).
Tests may include:
Cardiac catheterization (rarely needed, unless there are concerns of high blood pressure in the lungs)
Chest x-ray -- looks to see if there is a large heart with fluid in the lungs
ECG -- shows signs of an enlarged left ventricle
Echocardiogram -- used to make a definite diagnosis
MRI of the heart -- used to find out how much blood is getting to the lungs

11. Radiography:
Chest radiography may reveal the following:
Large VSDs with markedly increased pulmonary vascular resistance (PVR)
Right ventricular (RV) hypertrophy with the cardiac apex rotated slightly upward, to the left, and posteriorly
Markedly prominent main PA and adjacent vessels
Decreased pulmonary vascularity in the outer third of the lung fields
Essentially normal-sized heart
Small VSDs
Normal pulmonary vascularity
Moderate or large VSDs
Increased cardiac silhouette
Increased pulmonary vascular markings with a prominent main pulmonary artery (PA) segment
Enlarged left atrium (LA), which is visible on lateral radiographs

12. Ventricular septal defect
Echocardiographic image of a moderate ventricular septal defect in the mid-muscular part of the septum
Ventricular septal defect

13. Treatment
Small VSD: no treatment may be needed. But closely monitored to make sure that the hole eventually closes properly and signs of heart failure do not occur.
Large VSD: who have symptoms related to heart failure may need medicine to control the symptoms and surgery to close the hole. Medications may include digoxin and diuretics.
If symptoms continue, even with medication, surgery to close the defect with a patch is needed.
Some VSDs can be closed with a special device during a cardiac catheterization, which avoids the need for surgery, but only certain types of defects can successfully be treated this way.
Having surgery for a VSD with no symptoms is controversial.

14. Treatment
Most cases do not need treatment and heal at the first years of life. Treatment is either conservative or surgical. Smaller congenital VSDs often close on their own, as the heart grows, and in such cases may be treated conservatively. Some cases may necessitate surgical intervention, i.e. with the following indications:
1. Failure of congestive cardiac failure to respond to medications
2. VSD with pulmonic stenosis
3. Large VSD with pulmonary hypertension
4. VSD with aortic regurgitation

15. Clinical Scenarios & Recommendations
Symptomatic young infant with Pulm HTN
Early surgery within 3 months.
Medical therapy with diuretics +/- ACEI pre-op
Asymptomatic pt without Pulm HTN but with LV overload
Closure usually recommended to avoid late LV dysfunction
Asymptomatic pt, small VSD, no LV dilation
Conservative
Asymptomatic pt, small VSD but with AI/ prolapse
Peri-membranous VSD with more than trivial AI should have surgery