7th May 2025

Ventricular Septal Defects

Ventricular_septal_defect-en

Image Source: Wikimedia Commons (2008). Ventricular Septal Defect, Licensed under a creative commons licence. Available for free at:

https://upload.wikimedia.org/wikipedia/commons/e/e1/Ventricular_septal_defect-en.png?20080222192725 (Accessed 2 May 2025).

Ventricular Septal Defects (VSD) are often congenital abnormalities in the development of the interventricular septum (Figure Three). These anomalies result in an abnormal conduit between the left and right ventricles, which results in an often acyanotic left-to-right shunt. It is important to note that an untreated VSD can result in Eisenmenger syndrome, which results in a cyanotic right-to-left shunt. The key details of VSD are detailed in Table Four.

Feature	Summary
Epidemiology	The most common CHD in infants and children Isolated VSD occurs in 3.5 per 1000 live births but often close spontaneously. VSD can accompany other congenital defects, not just in isolation Acquired VSD secondary to trauma or myocardial infarction is rare Unusual for VSD to present in adults.
Aetiology	Multiple classification systems exist, but the easiest is to think of them as congenital vs acquired. Congenital No known definitive cause High incidence in those with Down’s syndrome Acquired Are rare causes Penetrating chest wall trauma 2-5 days after an acute myocardial infarction
Clinical History	Failure to thrive in infancy Shortness of breath on exertion Risk factors: Maternal alcohol use in pregnancy, Down’s syndrome, family history of CHD Repeated pulmonary infections: in shunt reversal associated with large defects
Clinical Examination	Holosystolic Systolic Murmur Loudest in the left parasternal region, the smaller the defect, the louder the murmur Loud pulmonary component of the second heart sound Indicative of pulmonary hypertension
Diagnostic Investigations	Echocardiogram – to visualise the VSD and confirmation of the left-to-right shunt. Chest x-ray – may be normal or show cardiomegaly. ECG – dependent on the size of the VSD, not diagnostic but supportive. In medium VSD can show signs of left ventricular hypertrophy.
Management	Once a diagnosis has been made utilising an echocardiogram, the pulmonary-systemic blood flow ratio (Qp:Qs) is calculated. Prophylactic antibiotics should be considered in all VSDs to prevent endocarditis. Congenital Small VSD (Qp:Qs <1) – monitoring and observation, they may spontaneously close. Medium/Large VSD (Qp:Qs ≥1.5) Asymptomatic Surgical closure to prevent progression into heart failure Symptomatic Preoperative medical treatment, e.g. diuretics, ACEi and digoxin Followed by surgical closure Eisenmenger’s Syndrome Supportive medical management, e.g. vasodilators Cardiopulmonary transplant Acquired Surgical repair
Follow Up	Annual follow-up of asymptomatic patients to monitor for development of complications. Patients who have corrective closure require monitoring for the development of heart block or arrhythmia. Potential complications include aortic regurgitation, heart block, arrhythmia and infective endocarditis. The prognosis is dependent on the size of the VSD. Asymptomatic: 50% will spontaneously close, and 50% will remain asymptomatic. Moderate VSD: if untreated, it will progress to congestive cardiac failure. If treated with surgical closure, then progress is excellent. Large VSD: if untreated, will progress faster to Eisenmenger syndrome, with a poor prognosis.

Table 4: This table describes the key features of ventricular septal defects. Sourced and adapted from Aggarwal, Ventricular septal defects: BMJ Best Practice; 2022.

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