Ventricular Septal Defects (VSD): Complete Case Discussion & Key Points
Model Case Presentation
Patient Demographics
Name: Master Aarav, Age: 4 months, Gender: Male, Informant: Mother (Reliable)
Chief Complaints
- Fast breathing and chest indrawing – 2 months
- Poor weight gain since birth
- Difficulty in feeding – 2 months
History Summary
Baby takes long to feed, actively sucks for a few minutes then leaves the breast, breathes rapidly, and sweats from the forehead before resuming (suck-rest-suck cycle). Fast breathing even during sleep. Had two episodes of fever with cough in the last 2 months requiring nebulization. No cyanosis, no squatting spells, no edema.
Born at term via NVD, cried immediately. Birth weight 2.8 kg. Antenatal period uneventful. Non-consanguineous marriage. No family history of CHD.
Examination Summary
| Parameter | Finding | Significance |
|---|---|---|
| Weight | 3.8 kg | Failure to Thrive (expected ~6 kg) |
| RR | 62/min | Tachypnea |
| HR | 150/min | Tachycardia |
| SpO2 | 98% | Normal (rules out cyanotic CHD) |
| Pallor | Present | — |
| Cyanosis | Absent | Acyanotic lesion |
Precordium: Prominent left precordium. Hyperdynamic apex at 5th ICS lateral to MCL (cardiomegaly). Systolic thrill at LLSB.
Auscultation: Loud, harsh, Grade 4/6 pansystolic murmur at left lower sternal border. Loud P2. Mid-diastolic murmur at apex (flow murmur – large shunt).
Other systems: Bilateral basal crepitations (pulmonary congestion). Hepatomegaly 3 cm below RCM (CCF).
✅ Complete Diagnosis
Acyanotic Congenital Heart Disease — Large Ventricular Septal Defect (Perimembranous) with Left-to-Right Shunt, in Congestive Heart Failure with Failure to Thrive and Moderate Pulmonary Arterial Hypertension.
📝 History — Exam Q&A
VSD is the most common congenital heart disease, accounting for ~25-30% of all CHDs.
- Failure to thrive / poor weight gain
- Feeding difficulty (suck-rest-suck cycle, diaphoresis during feeds)
- Tachypnea, recurrent lower respiratory tract infections
- Features of congestive heart failure (tachycardia, hepatomegaly)
At birth, pulmonary vascular resistance (PVR) is high (equal to systemic). There is minimal pressure gradient across the VSD → minimal shunt → no/soft murmur. As PVR falls over the first 4-8 weeks, the left-to-right shunt increases and the murmur becomes audible.
The infant sucks briefly, then stops to breathe rapidly, then resumes feeding. This occurs because feeding increases metabolic demand in a heart that is already working overtime due to volume overload. The baby becomes breathless and sweaty and needs to rest between efforts.
- No cyanosis — Rules out cyanotic CHD (TOF, TGA)
- No squatting episodes — Rules out Tet spells
- No edema — Degree of heart failure
- Antenatal: No maternal rubella, drugs, diabetes — Rules out teratogenic causes
- Family: No CHD in siblings — Recurrence risk assessment
| Type | Location | Frequency |
|---|---|---|
| Perimembranous | Adjacent to TV & aortic valve | ~80% (most common) |
| Muscular | Entirely within muscular septum | ~5-20% |
| Supracristal (Doubly committed subarterial) | Below aortic & pulmonary valves | ~5-7% (higher in Asians) |
| Inlet (AV canal type) | Near AV valves | ~5-8% |
| Feature | Small (Restrictive) | Moderate | Large (Non-Restrictive) |
|---|---|---|---|
| Size | < 1/3 of aortic annulus | 1/3 to 2/3 | > 2/3 or equal |
| Symptoms | Asymptomatic | Mild FTT, mild symptoms | CCF, severe FTT |
| Murmur | Loud, Grade 3-4 PSM | Loud PSM | Soft PSM (paradox) |
| PA pressure | Normal | Mildly elevated | Near-systemic |
| Shunt (Qp:Qs) | < 1.5:1 | 1.5-2:1 | > 2:1 |
💡 Maladie de Roger
A small restrictive VSD with a loud murmur but no hemodynamic significance is called Maladie de Roger. These often close spontaneously.
🩺 Examination — Exam Q&A
Inspection: Precordial bulge (chronic cardiomegaly), visible pulsations.
Palpation: Apex beat location (displaced = cardiomegaly), character (hyperdynamic = volume overload), thrills (location = origin of murmur), parasternal heave (RV overload).
Auscultation: S1, S2 (split, P2 intensity), murmurs (timing, location, grade, radiation), added sounds.
Pansystolic (holosystolic) murmur — starts with S1, continues up to S2 without a gap. Best heard at the left lower sternal border (3rd-4th ICS). It radiates to the right sternal border. Grade depends on size of VSD and pressure gradient.
A loud P2 (pulmonary component of S2) indicates pulmonary arterial hypertension (PAH). In VSD, it suggests the large left-to-right shunt is causing elevated pulmonary artery pressures due to increased pulmonary blood flow.
It indicates a large shunt (Qp:Qs > 2:1). Massive pulmonary venous return to the left atrium creates relative mitral stenosis — blood rushes across a normal-sized mitral valve producing a flow murmur. It is a sign of hemodynamic significance.
Murmur intensity depends on the pressure gradient and velocity of flow across the defect.
- Small VSD: High pressure gradient between LV and RV → high velocity jet through a narrow hole → loud turbulent murmur.
- Large VSD: Pressures equalize between LV and RV → low gradient → slow, laminar flow → soft murmur.
This is the "inverse relationship" — a softer murmur paradoxically implies a more dangerous defect.
- Tachycardia, tachypnea, diaphoresis (especially during feeds)
- Hepatomegaly (most reliable sign in infants)
- Failure to thrive / poor weight gain
- Gallop rhythm (S3)
- Bilateral basal crepitations
- Periorbital/pedal edema (late sign in infants)
Eisenmenger Syndrome occurs when a chronic left-to-right shunt causes irreversible pulmonary vascular disease → PVR exceeds SVR → shunt reverses to right-to-left → cyanosis.
Examination changes:
- Central cyanosis and clubbing appear
- Pansystolic murmur becomes softer or disappears
- Loud single S2 (P2 = A2)
- Graham-Steell murmur (early diastolic murmur of pulmonary regurgitation)
- Signs of polycythemia (plethora)
🚨 Key Point
Once Eisenmenger develops, surgical closure is contraindicated. The only option is medical management or heart-lung transplant.
🔬 Investigations — Exam Q&A
- Cardiomegaly (CT ratio > 0.55 in infants)
- Biventricular enlargement
- Prominent main pulmonary artery segment
- Pulmonary plethora — increased vascular markings extending to the periphery of both lung fields
| VSD Size | ECG Pattern |
|---|---|
| Small | Normal ECG |
| Moderate | Left ventricular hypertrophy (tall R in V5-V6) |
| Large | Biventricular hypertrophy + Left atrial enlargement |
| Eisenmenger | Pure RVH with right axis deviation |
2D Echocardiography with Color Doppler — It provides:
- Location and size of defect
- Direction and volume of shunt
- Chamber dimensions (LA, LV dilatation)
- Estimation of PA pressure (from TR jet velocity)
- Associated anomalies (AR in supracristal VSD)
Not routinely needed. Indications include:
- Assessment of pulmonary vascular resistance (PVR) when PAH is suspected
- Testing reactivity of pulmonary vasculature (O2 or iNO challenge) to determine if patient is operable
- Before surgery if echo findings are inconclusive
- Interventional: Device closure of muscular VSDs
Operability criteria: PVR < 8 Wood units, PVR/SVR ratio < 0.66, Qp:Qs > 1.5:1.
💊 Management — Exam Q&A
- Diuretics: Furosemide (1-2 mg/kg/day) + Spironolactone (1-2 mg/kg/day)
- ACE Inhibitor: Enalapril/Captopril — reduces afterload, decreases L→R shunt
- Digoxin: Mild inotropic, helps with heart failure symptoms
- High-calorie feeds: 120-150 kcal/kg/day, frequent small feeds or NG tube if needed
- Treat infections: Prompt treatment of respiratory infections
- Large VSD with heart failure not responding to medical therapy
- Large VSD with failure to thrive despite optimal nutrition
- Moderate-large VSD with Qp:Qs > 2:1
- Developing PAH (before Eisenmenger occurs)
- Supracristal VSD — early closure to prevent aortic regurgitation
- Infective endocarditis (relative indication)
Ideal timing: Within 3-6 months if symptomatic. By 1-2 years if moderate with PAH.
- Small perimembranous and muscular VSDs can close spontaneously
- Rate: ~30-40% close by 3-5 years of age
- Supracristal VSDs do NOT close spontaneously (no tissue to cover the defect)
- Large VSDs rarely close on their own
Mechanism: Adherence of septal leaflet of tricuspid valve ("aneurysm of membranous septum") or muscular hypertrophy.
- Eisenmenger Syndrome — irreversible PAH with shunt reversal
- Infective Endocarditis
- Aortic Regurgitation — especially in supracristal VSD (prolapse of right coronary cusp)
- DCRV (Double Chambered Right Ventricle) — muscular bundles obstruct RV outflow
- Recurrent pulmonary infections
- Growth failure
As per AHA 2007 guidelines (latest):
- IE prophylaxis is NOT routinely recommended for unrepaired VSD
- Recommended only for: First 6 months after surgical repair with prosthetic material, or if there is a residual defect near prosthetic patch, or history of previous IE
🔭 Recent Advances — Exam Q&A
A minimally invasive alternative to open heart surgery. A catheter-delivered occluder device is placed across the defect.
- Best suited for: Muscular VSDs (especially in the mid-muscular septum)
- Devices used: Amplatzer Muscular VSD Occluder, Amplatzer Perimembranous VSD Occluder
- Advantage: No sternotomy, shorter hospital stay, no cardiopulmonary bypass
- Limitations: Not ideal for all perimembranous VSDs (risk of heart block due to proximity to conduction system)
A combined surgical + interventional approach where the surgeon makes a small incision (mini-sternotomy) and the device is deployed under direct vision using echocardiographic guidance, without cardiopulmonary bypass. Useful in small infants where vascular access is limited.
In patients with borderline operability (elevated but reactive PVR):
- Sildenafil (PDE-5 inhibitor) — used to reduce PVR pre-operatively
- Bosentan (Endothelin receptor antagonist) — used in established Eisenmenger to improve functional capacity
- Inhaled Nitric Oxide — used in the cath lab to test pulmonary vasoreactivity
These are NOT curative but improve quality of life and help in borderline surgical decisions.
⚡ Key Points — Quick Revision
One-Liners for Exam
- Most common CHD: VSD
- Most common type: Perimembranous (80%)
- VSD murmur: Pansystolic at LLSB
- Maladie de Roger: Small VSD, loud murmur, no hemodynamic significance
- Eisenmenger: Irreversible PAH → shunt reversal → cyanosis → surgery contraindicated
- Loud P2: Indicates pulmonary hypertension
- Apical MDM in VSD: Indicates large shunt (Qp:Qs > 2:1)
- Supracristal VSD risk: Aortic regurgitation (RCC prolapse)
- Gold standard: 2D Echo with Color Doppler
- CXR: Cardiomegaly + Pulmonary plethora
- Medical Rx: Furosemide + ACE inhibitor + Digoxin + High-calorie feeds
- Surgical Rx: Patch closure under CPB — within 6 months if symptomatic
- Spontaneous closure: Small perimembranous & muscular VSDs; NOT supracristal
- Device closure: Best for muscular VSDs (Amplatzer device)